WO2015031561A1

WO2015031561A1 - Catalytic conversion of alcohols

Info

Publication number: WO2015031561A1
Application number: PCT/US2014/053053
Authority: WO
Inventors: Duncan Frank Wass
Original assignee: Bp Corporation North America Inc.
Priority date: 2013-08-30
Filing date: 2014-08-28
Publication date: 2015-03-05

Abstract

The disclosure provides methods of converting a lower alcohol (e.g., ethanol) to a higher alcohol (e.g., butanol) in the presence of a water stable transition metal catalyst comprising a Group VIII transition metal and a polydentate nitrogen donor ligand. The methods described in the disclosure can be carried out in the presence of water and achieve high purities of the higher alcohols.

Description

CATALYTIC CONVERSION OF ALCOHOLS

1. CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 USC § 119(e)(1) of prior U.S. Provisional Patent Application Serial No. 61/872,079, filed August 30, 2013, which is hereby incorporated by reference in its entirety.

2. FIELD OF INVENTION

[0002] This disclosure relates to synthetic processes for converting lower alcohols (e.g., ethanol) to higher alcohols (e.g., butanol) catalyzed by water stable transition metal complexes comprising a Group VIII transition metal and a polydentate nitrogen donor ligand.

3. BACKGROUND

[0003] The desirability for alternative liquid fuels over fossil fuels has led to the emergence and development of so-called biofuels as a valuable alternative. Biofuels include fuels which are derived partly or fully from biomass that may be used as a replacement for fossil fuel or that may be utilized as a component blended with fossil fuels, for example in gasoline. Biofuel alternatives or components for gasoline include ethanol and butanol. In general, the latter alcohol is considered to be a more advanced fuel because its fuel performance parameters, such as energy density, are greater than those of ethanol and are much closer to those of conventional gasoline. Butanol can also be blended into conventional gasoline in higher amounts compared with ethanol. Currently known processes for the manufacture of butanol largely rely on biosynthetic pathways from fermentable sugars. These routes currently have the disadvantage of low conversion rate. An alternative route is to convert biomass- derived ethanol into butanol by a catalyzed reaction sequence, often called the 'Guerbet' or 'borrowed hydrogen' reaction (Nixon et ah, 2009, Dalton Transaction, 753 - 762). This reaction is described in the academic literature as having three stages: (1) dehydrogenation of an alcohol (for example, ethanol) to an aldehyde (for example acetaldehyde); (2) dimerization and dehydration of this aldehyde via an aldol reaction; and (3) re-hydrogenation of the aldol product to a new alcohol (for example, butanol). This reaction sequence has been described for a wide variety of alcohols; however, ethanol is known to be a particularly challenging starting material (Carlini et al, 2003, Journal of Molecular Catalysis A: Chemical, 200:Pages 137-146) and more efficient processes for the conversion of ethanol to butanol are currently unknown. The production of butanol from ethanol using iridium catalysts has been reported (Koda et ah, 2009, Chemistry Letters, 38:838). However, the selectivity of the reaction is relatively poor with butanol accounting for only a small percentage of the products obtained.

[0004] WO/2012/004572, which is hereby incorporated by reference in its entirety, describes a described high selectivity method for the conversion of alcohols to higher alcohols, for example ethanol to butanol. However, the performance of the catalysts described according to this method can be limited by the amount of water present in the starting alcohol. Generally, catalysts, and particularly organometallic catalysts, are sensitive to water, which can lead to catalyst poisoning and catalyst deactivation. Because biosynthetically-produced alcohols such as ethanol are typically diluted by large amounts of water, and the separation of water from alcohols such as ethanol is difficult, it is challenging to achieve very low water concentrations in biosynthetically produced alcohols. Accordingly, the development of a catalyzed process for the conversion of ethanol to higher alcohols that can achieve high selectivity to the desired alcohol(s), for example butanol, in the presence of high water concentrations would be highly advantageous. The catalyzed processes described herein have such advantages.

4. SUMMARY

[0005] The disclosure relates to catalytic methods of converting lower molecular weight alcohols (i.e., lower alcohols) to higher molecular weight alcohols (i.e., higher alcohols). The catalysts of the disclosure comprise a Group VIII transition metal complexed to a polydentate nitrogen donor ligand. Preferably, the catalysts are stable in water and hence, the catalytic conversions can be achieved in the presence of water. Moreover, the catalytic conversions described herein provide higher order alcohols such as 1 -butanol and hexan-l-ol with high selectivities.

[0006] According to one aspect of the disclosure there is provided a method for converting a first alcohol into a second alcohol, the method comprising the step of contacting the first alcohol with a transition metal catalyst comprising a Group VIII transition metal selected from Ru, Fe and Os complexed to a polydentate nitrogen donor ligand. The first alcohol has a molecular weight that is lower than the second alcohol. In certain embodiments, the first alcohol is a lower alcohol containing two or three carbon atoms and the second alcohol is a higher alcohol containing between four and ten carbons (e.g. 4, 5, 6, 7, 8, 9, or 10 carbon atoms). In particular embodiments, the first alcohol is ethanol and the second alcohol is 1 -butanol (also referred to as n-butanol). In other embodiments, the first alcohol is ethanol and the second alcohol is hexan-l-ol.

[0007] In particular embodiments, the transition metal catalyst is water soluble. In other embodiments, the transition metal catalyst is water stable. In other embodiments, the transition metal catalyst is both water stable and water soluble. [0008] The methods of the disclosure can be carried in the presence of water without significant diminuition of catalyst activity. The catalytic conversions of the disclosure can be carried out in the presence of 5% v/v water or more and still retain catalytic activity. For instance, in particular embodiments, the conversion of ethanol to 1-butanol using a transition metal catalyst of the disclosure can be carried out in the presence of 5% v/v water, 10% v/v water, 15% v/v water, 20% v/v water or 25% v/v water. In particular embodiments, the catalytic conversions of the disclosure can be carried out in the presence of 5% v/v water, 6% v/v water, 7% v/v water, 8% v/v water, 9% v/v water, 10% v/v water, 1 1% v/v water, 12% v/v water, 13% v/v water, 14% v/v water, 15% v/v water, 16% v/v water, 17% v/v water, 18% v/v water, 19% v/v water, 20% v/v water, 25% v/v water, and still retain catalytic activity. In particular embodiments, the catalytic conversions of the disclosure can be carried out in the presence of 5% or more v/v water, 6% or more v/v water, 7% or more v/v water, 8% or more v/v water, 9% or more v/v water, 10% or more v/v water, 1 1% or more v/v water, 12% or more v/v water, 13% or more v/v water, 14% or more v/v water, 15% or more v/v water, 16% or more v/v water, 17% or more v/v water, 18% or more v/v water, 19% or more v/v water, 20% or more v/v water, 25% or more v/v water, and still retain catalytic activity. Accordingly, the disclosure provides methods of catalytically converting lower alcohols into higher alcohols in the presence of water.

[0009] In some embodiments, the catalytic methods of the disclosure can be carried out in the presence of a base. In particular embodiments, the base is selected from potassium i-butoxide (KOtBu), potassium ethoxide (KOEt) and potassium hydroxide (KOH).

[0010] The transition metal catalysts of the disclosure can be formed by admixing a source of the Group VIII transition metal such as a transition metal complex with a nitrogen donor polydentate ligand under conditions suitable to coordinate the metal comprising the transition metal complex and at least two nitrogen atoms (and possibly other heteroatoms) of the ligand, thereby forming a transition metal catalyst. In the process, at least two atoms of the transition metal complex are displaced. In particular embodiments, the transition metal catalyst is a salt. In such embodiments, the transition metal catalyst contains a non-coordinating counterion such as CI, Br, I, BF₄, PF₆ or SbF₆.

[0011] In certain embodiments, the polydentate nitrogen donor ligand of the transition metal catalyst can be a bidentate, tridentate or tetradentate ligand with respect to the Group VIII metal. The catalyst can include two or more ligands, which can have the same or different denticity from each other. The catalyst can be in the same phase (i.e., homogeneous catalyst) or in a different phase (i.e., heterogeneous catalyst) than the lower alcohol.

[0012] In certain embodiments, the transition metal catalyst is formed in situ in the reaction vessel without isolation. In other examples, the transition metal can be pre-formed and added to the reaction vessel containing the first alcohol and optionally, a suitable base.

[0013] In some embodiments, the polydentate nitrogen donor ligand has the Formula (I):

(I)

wherein:

(i) Qi and Q₂ are each independently a 5- or 6-membered monocyclic aromatic or non- aromatic heterocyclic ring containing at least one nitrogen atom;

(ii) each (R and (R²)_b are independently selected from:

(a) halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec -butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C₂-Q)alkenyl, -(C₂-Q)alkynyl, and -(Ci-C₆)alkoxy; or

(b) the R¹ and R² groups form a (C₂-C₄)bridge that is either saturated or unsaturated, wherein said bridge is unsubstituted or substituted with 1 , 2, 3, or 4 substitutents selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t- butyl, sec -butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl;

(iii) a is an integer selected from 0, 1 , 2 and 3;

(iv) b is an integer selected from 0, 1 , 2 and 3;

(v) X is selected from:

(a) methylene, ethylene, ethenylene, propylene, ethynediyl, sulfur, and oxygen; or

(b) phenylene, pyridylene, furylene, phenylene, biphenylene, naphthylene, pyrazinylene, pyrimidinylene, pyridazinylene, thienylene, pyrrolylene, imidazolylene, pyrazolylene, thiazolylene, isothiazolylene, oxazolylene, isoxazolylene, furazanylene, and oxadiazolylene, which can be optionally substituted with one or more R³ groups; or

(c) a bond

(vi) each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl. [0014] In certain embodiments, the polydentate nitrogen donor ligand is 1,10-phenantroline or a substituted 1,10-phenanthroline. In some such embodiments, the 1 ,10-phenantroline derivative has one of the following chemical structures:

[0015] In some embodiments in which the polydentate ligand is 1,10-phenanthroline, the transition metal catalyst is selected from [Ru(r|⁶-/ cymene)(phen)Cl]Cl, [Ru(r|⁶-/?-cymene)(phen)Cl]PF₆, [Ru(rj⁶-cymene)(phen)H]PF₆, [Ru(r|⁵-C5H5)(phen)Cl], [Ru(phen)(Cl)^-Cl)]₂, and [Ru(phen)₂Cl₂].

[0016] In particular embodiments, the transition metal catalyst has one of the following chemical structures:

5. BRIEF DESCRIPTION OF FIGURES

[0017] FIG. 1 shows the percent of ethanol conversion as a function of catalyst loading (mol%) after the reaction was run for 4 hours at 150°C in the presence of 5 mol% potassium hydroxide (KOH).

[Ru^⁵-C₅H₅)( phen)Cl] was used as the catalyst.

[0018] FIG. 2 shows the effect of different transition metal catalysts on the conversion of ethanol to 1-butanol.

[0019] FIG. 3 shows the effect of different 1-10-phenanthroline derived ligands on the conversion of ethanol to 1-butanol.

[0020] FIG. 4 shows the catalytic conversion of ethanol to 1-butanol as a function of increasing initial water volume after 4 hours reaction of ethanol in the presence of 0.1 mol% of the transition metal catalyst [Ru(r|⁵-C₅H₅)( phen)Cl] (diamond shapes) or a diphosphine ligand catalyst (square shapes) and 5 mol% of the base sodium ethoxide (NaOEt) at a temperature of 150°C. [0021] FIG. 5 shows selectivity as a function of catalyst loading (mol%) after the reaction was run for 4 hours at 150^°C in the presence of 5 mol% potassium hydroxide (KOH). [Ru(r|⁵-C₅H₅)( phen)Cl] was used as the transition metal catalyst.

[0022] FIG. 6 shows a schematic depiction of an integrated process including production of a lower alcohol followed by conversion of the lower alcohol to a higher alcohol.

6. DETAILED DESCRIPTION 6.1. Alcohols

[0023] According to one aspect of the disclosure, there is provided a catalytic method for converting a first alcohol into a second alcohol. Generally, the first alcohol is a lower molecular weight alcohol such as ethanol or propanol and the second alcohol has a molecular weight that is greater than the first alcohol. In one embodiment, the lower alcohol is ethanol. In one embodiment, the lower alcohol is propanol. Accordingly, the disclosure provides catalytic methods of converting lower alcohols into higher alcohols.

[0024] The second alcohol (higher alcohol) preferably has the general formula H(C₂H₄)_nOH , wherein n = 2, 3 or 4. In certain embodiments, the second alcohol is one of the isomers of butanol, such as 1 -butanol. Where reference is made herein generally to butanol, the term includes isobutanol (or 2-methyl 1 -propanol), 1 -butanol and/or 2-butanol. In particular embodiments described herein, the butanol formed substantially, or completely, consists of 1 -butanol. In other embodiments, the second alcohol is hexan-l-ol.

[0025] In some embodiments, the first alcohol is ethanol and the second alcohol is 1 -butanol. In other embodiments, the first alcohol is ethanol and the second alcohol is hexan-l-ol. In other embodiments, the second (higher alcohol) can represent the final product; in other examples, the second alcohol can be subject to further conversion, to the product, for example to an alkene. For example, 1 -butanol can be converted to 1-butene or hexan-l -ol can be converted to 1-hexene. The further conversion can be effected using the same or additional conversion catalyst, which can be present in combination with the catalyst, or can be physically separate. Similarly, the starting composition can be a pre-cursor to an alcohol in some examples, for example an acetaldehyde or an alkene (e.g., ethylene).

[0026] In some embodiments where butanol is formed as a product, the method can be selective to the production of one or more types of butanol. For example, the butanol produced can be substantially all 1 -butanol. In other embodiments, substantially all the butanol can be 2-butanol. Preferably the conversion products include less than 10% by weight of 2-ethylbutanol and hexan-l-ol e.g. less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2% or less than 1 % by weight.

[0027] The first alcohol (lower alcohol) can be pretreated prior to conversion in order to achieve the preferred conditions for reaction, which will vary according to the alcohol which is to be converted. Pretreatment can include the removal of trace contaminants deleterious to the process, and/or heating/cooling to preferred reaction conditions (phase, temperature and pressure). In some embodiments, the reactant (i.e., lower alcohol) alcohol can be purified prior to reaction to remove unwanted minor components such as the fusel alcohols.

[0028] In other embodiments, fusel alcohols are not removed from the lower alcohol prior to conversion to the higher alcohol. In such embodiments, the fusel alcohols can react to give minor product components. These minor product components can be subsequently separated from the main product if desired.

[0029] In certain embodiments, a single lower alcohol can be converted to a single higher alcohol. In other embodiments, a mixture of lower alcohols can be converted to a mixture of higher alcohol products.

[0030] Additional products can be formed from the 1-butanol produced in by methods of the disclosure. In one such embodiment, 2-ethylhexanol can be produced from 1-butanol manufactured in accordance with methods of the disclosure. The 2-ethylhexanol can be used to produce plasticizers such as 2-ethylhextl phthalate. In other embodiments, the 1-butanol produced in accordance with methods of the disclosure can be used to produce 1-butyylacetate, ethyl acetate, hexan-l-ol, 2- ethylbutan-l-ol, 1-octanol or 2-ethylhexan-l-ol.

6.1.1 Ethanol As the Lower Alcohol

[0031] In certain aspects of the disclosure, the alcohol to be converted (i.e., the lower alcohol) comprises ethanol. The ethanol used in the reaction can be produced synthetically through the hydration of ethylene or acetylene. Alternatively, as discussed below, the ethanol can be produced from biosynthetic conversion (fermentation) of biomass. In particular embodiments, the method can be used to convert bio-ethanol, for example ethanol which is derived from biomass or ethanol produced by the fermentation of sugars. Generally, ethanol derived from biomass or from fermentation contains a certain percentage of water (e.g., about 5% or more water by volume). The amount of water in the ethanol can be reduced using techniques known in the art, such as azeotropic distillation or through the use of adsorption. However, the methods of the disclosure can be carried out readily in the presence of water without significantly compromising yield or selectivity (see, e.g., FIG. 4). Hence, in particular embodiments of the disclosure, the ethanol is not subjected to additional purification (e.g., azeotropic distillation) prior to reaction. [0032] The fermentation of sugars to ethanol can be carried out by one or more appropriate fermenting microorganisms in single or multistep fermentations. Fermenting microorganisms can be wild type microorganisms or recombinant microorganisms, and include Escherichia, Zymomonas, Saccharomyces, Candida, Pichia, Streptomyces, Bacillus, Lactobacillus, and Clostridium.

Particularly suitable species of fermenting microorganisms include Escherichia coli, Zymomonas mobilis, Bacillus stearothermophilus, Saccharomyces cerevisiae, Clostridia thermocellum, kluveromyces, Thermoanaerobacterium saccharolyticum, and Pichia stipitis. Genetically modified strains of E. coli or Zymomonas mobilis can be used for ethanol production (see, e.g., Underwood et al, 2002, Appl. Environ. Microbiol. 68:6263-6272 and US 2003/0162271 Al).

[0033] The fermentation can be carried out in a minimal media with or without additional nutrients such as vitamins and corn steep liquor (CSL). The fermentation can be carried out in any suitable fermentation vessel known in the art. For instance, fermentation can be carried out in an Erlenmeyer flask, Fleaker, DasGip fedbatch-pro (DasGip technology), 2L BioFlo fermenter or 10L fermenter (B. Braun Biotech) or a commercial size fermenter. The fermentation process can be performed as a batch, fed-batch or as a continuous process. Typical fermentable sugars for production of ethanol include glucose, mannose, fructose, sucrose, galactose, xylose, arabinose and cellobiose.

[0034] Fermentation products can be recovered using various methods known in the art. Products can be separated from other fermentation components by centrifugation, filtration, microfiltration, and nanofiltration. Products can be extracted by ion exchange, solvent extraction, or electrodialysis. Flocculating agents can be used to aid in product separation. As a specific example, bioproduced ethanol can be isolated from the fermentation medium using methods known in the art for ABE fermentations (see for example, Durre, 1998, Appl. Microbiol. Biotechnol. 49:639-648; Groot et al., 1992, Process. Biochem. 27:61 -75; and references therein). For example, solids can be removed from the fermentation medium by centrifugation, filtration, decantation, or the like.

[0035] After fermentation, the ethanol can be separated from the fermentation broth by any of the many conventional techniques known to separate ethanol from aqueous solutions. These methods include evaporation, distillation, azeotropic distillation, solvent extraction, liquid-liquid extraction, membrane separation, membrane evaporation, adsorption, gas stripping, pervaporation, and the like.

[0036] The fermentable sugars used to produce ethanol can be produced through hydrolysis of biomass. The term "biomass," as used herein, refers to any composition comprising cellulose (optionally also hemicellulose and/or lignin). The hydrolyzed biomass (i.e., hydro lysate) can be detoxified prior to fermentation.

[0037] Relevant types of biomasses which can be hydrolyzed or detoxified according to the methods of the disclosure can include biomasses obtained from agricultural crops such as, e.g., containing grains; corn stover, grass, bagasse, straw, e.g., from rice, wheat, rye, oat, barley, rape, sorghum; tubers, e.g. , beet and potato. The biomass is preferably lignocellulosic. The lignocellulosic biomass is suitably from the grass family. The proper name is the family known as Poaceae or Gramineae in the class Liliopsida (the monocots) of the flowering plants. Plants of this family are usually called grasses, and include bamboo. There are about 600 genera and some 9,000-10,000 or more species of grasses (Kew Index of World Grass Species).

[0038] Poaceae includes the staple food grains and cereal crops grown around the world, lawn and forage grasses, and bamboo.

[0039] The success of the grasses lies in part in their morphology and growth processes, and in part in their physiological diversity. Most of the grasses divide into two physiological groups, using the C3 and C4 photosynthetic pathways for carbon fixation. The C4 grasses have a photo synthetic pathway linked to specialized leaf anatomy that particularly adapts them to hot climates and an atmosphere low in carbon dioxide. C3 grasses are referred to as "cool season grasses" while C4 plants are considered "warm season grasses".

[0040] Grasses can be either annual or perennial. Examples of annual cool season are wheat, rye, annual bluegrass (annual meadowgrass, Poa annua and oat). Examples of perennial cool season are orchardgrass (cocksfoot, Dactylis glomerata), fescue (Festuca spp.), Kentucky bluegrass and perennial ryegrass {Lolium perenne). Examples of annual warm season are corn, sudangrass and pearl millet. Examples of Perennial Warm Season are big bluestem, indiangrass, bermudagrass and switchgrass.

[0041] One classification of the grass family recognizes twelve subfamilies: These are 1) anomochlooideae, a small lineage of broad-leaved grasses that includes two genera (Anomochloa, Streptochaeta); 2) Pharoideae (aka Poaceae), a small lineage of grasses that includes three genera, including Pharus and Leptaspis; 3) Puelioideae a small lineage that includes the African genus Puelia; 4) Pooideae which includes wheat, barley, oats, brome-grass (Bromus) and reed-grasses (Calamagrostis); 5) Bambusoideae which includes bamboo; 6) Ehrhartoideae, which includes rice, and wild rice; 7) Arundinoideae, which includes the giant reed and common reed 8) Centothecoideae, a small subfamily of 1 1 genera that is sometimes included in Panicoideae; 9) Chloridoideae including the lovegrasses (Eragrostis, ca. 350 species, including teff), dropseed grasses (Sporobolus, some 160 species), finger millet (Eleusine coracana (L.) Gaertn.), and the muhly grasses (Muhlenbergia, ca. 175 species); 10) Panicoideae including panic grass, maize, sorghum, sugar cane, most millets, fonio and bluestem grasses; 11) Micrairoideae; 12) Danthoniodieae including pampas grass; with Poa which is a genus of about 500 species of grasses, native to the temperate regions of both hemisphere.

[0042] Agricultural grasses grown for their edible seeds are called cereals. Three common cereals are rice, wheat and maize (corn). Of all crops, 70% are grasses. [0043] Therefore a preferred biomass is selected from the group consisting of the energy crops. In a further preferred embodiment, the energy crops are grasses. Preferred grasses include Napier Grass or Uganda Grass, such as Pennisetum purpureum; or, Miscanthus; such as Miscanthus giganteus and other varieties of the genus miscanthus, or Indian grass, such as Sorghastrum nutans; or, switchgrass, e.g. , as Panicum virgatum or other varieties of the genus Panicum), giant reed (arundo donax), energy cane (saccharum spp.)., wood (including, e.g., wood chips, processing waste), paper, pulp, and recycled paper (including, e.g., newspaper, printer paper, and the like). In some embodiments the biomass is sugarcane, which refers to any species of tall perennial grasses of the genus Saccharum.

[0044] Other types of biomass include seeds, grains, tuber {e.g., potatoes and beets), plant waste or byproducts of food processing or industrial processing {e.g., stalks), corn and corn byproducts (including, e.g. , corn husks, corn cobs, corn fiber, corn stover, and the like), wood and wood byproducts (including, e.g. , processing waste, deciduous wood, coniferous wood, wood chips {e.g., deciduous or coniferous wood chips), sawdust {e.g., deciduous or coniferous sawdust)), paper and paper byproducts {e.g. , pulp, mill waste, and recycled paper, including, e.g., newspaper, printer paper, and the like), soybean {e.g., rapeseed), barley, rye, oats, wheat, beets, sorghum sudan, milo, bulgur, rice, sugar cane bagasse, forest residue, agricultural residues, quinoa, wheat straw, milo stubble, citrus waste, urban green waste or residue, food manufacturing industry waste or residue, cereal manufacturing waste or residue, hay, straw, rice straw, grain cleanings, spent brewer's grain, rice hulls, salix, spruce, poplar, eucalyptus, Brassica carinata residue, Antigonum leptopus, sweetgum, Sericea lespedeza, Chinese tallow, hemp, rapeseed, Sorghum bicolor, soybeans and soybean products (soybean leaves, soybeans stems, soybean pods, and soybean residue), sunflowers and sunflower products {e.g. , leaves, sunflower stems, seedless sunflower heads, sunflower hulls, and sunflower residue), Arundo, nut shells, deciduous leaves, cotton fiber, manure, coastal Bermuda grass, clover, Johnsongrass, flax, straw {e.g. , barley straw, buckwheat straw, oat straw, millet straw, rye straw amaranth straw, spelt straw), amaranth and amaranth products {e.g., amaranth stems, amaranth leaves, and amaranth residue), alfalfa, and bamboo.

[0045] Yet further sources of biomass include hardwood and softwood. Examples of suitable softwood and hardwood trees include, but are not limited to, the following: pine trees, such as loblolly pine, jack pine, Caribbean pine, lodgepole pine, shortleaf pine, slash pine, Honduran pine, Masson's pine, Sumatran pine, western white pine, egg-cone pine, longleaf pine, patula pine, maritime pine, ponderosa pine, Monterey pine, red pine, eastern white pine, Scots pine, araucaria tress; fir trees, such as Douglas fir; and hemlock trees, plus hybrids of any of the foregoing. Additional examples include, but are not limited to, the following: eucalyptus trees, such as Dunn's white gum, Tasmanian blue gum, rose gum, Sydney blue gum, Timor white gum, and the E. urograndis hybrid; populus trees, such as eastern cottonwood, bigtooth aspen, quaking aspen, and black cottonwood; and other hardwood trees, such as red alder, Sweetgum, tulip tree, Oregon ash, green ash, and willow, plus hybrids of any of the foregoing.

[0046] Any hydrolysis process can be used to prepare lignocellulosic hydrolysates, including acid hydrolysis and base hydrolysis. Acid hydrolysis is a cheap and fast method and can suitably be used. A concentrated acid hydrolysis is preferably operated at temperatures from 20°C to 100°C, and an acid strength in the range of 10% to 45%. Dilute acid hydrolysis is a simpler process, but is optimal at higher temperatures (100°C to 230°C) and pressure. Different kinds of acids, with concentrations in the range of 0.001% to 10% (e.g., 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, or any range bounded by any two of the foregoing values) are preferably used. Suitable acids including nitric acid, sulfurous acid, nitrous acid, phosphoric acid, acetic acid, hydrochloric acid and sulfuric acid can be used in the hydrolysis step. Depending on the acid concentration, and the temperature and pressure under which the acid hydrolysis step is carried out, corrosion resistant equipment and/or pressure tolerant equipment may be needed.

[0047] Variations of acid hydrolysis methods are known in the art and are encompassed by the methods of the present disclosure. For instance, the hydrolysis can be carried out by subjecting the biomass material to a two step process. The first (chemical) hydrolysis step is carried out in an aqueous medium at a temperature and a pressure chosen to effectuate primarily depolymerization of hemicellulose without achieving significant depolymerization of cellulose into glucose. This step yields slurry in which the liquid aqueous phase contains dissolved monosaccharides and soluble and insoluble oligomers of hemicellulose resulting from depolymerization of hemicellulose, and a solid phase containing cellulose and lignin. See, e.g., U.S. Patent No. 5,536,325. In a preferred embodiment, sulfuric acid is utilized to affect the first hydrolysis step. After the sugars are separated from the first-stage hydrolysis process, the second hydrolysis step is run under harsher condition to hydrolyze the more resistant cellulose fractions.

[0048] In another embodiment, the hydrolysis method entails subjecting biomass material to a catalyst comprising a dilute solution of a strong acid and a metal salt in a reactor. The biomass material can, e.g., be a raw material or a dried material. This type of hydrolysis may lower the activation energy, or the temperature, of cellulose hydrolysis, ultimately allowing higher yields of fermentable sugars. See, e.g., U.S. Patent Nos. 6,660,506; 6,423,145.

[0049] A further exemplary method involves processing a biomass material by one or more stages of dilute acid hydrolysis using about 0.4% to about 2% of an acid; followed by treating the unreacted solid lignocellulosic component of the acid hydrolyzed material with alkaline delignification. See, e.g., U.S. Patent No. 6,409,841. Another exemplary hydrolysis method comprises prehydrolyzing biomass (e.g., lignocellulosic materials) in a prehydro lysis reactor; adding an acidic liquid to the solid lignocellulosic material to make a mixture; heating the mixture to reaction temperature; maintaining reaction temperature for a period of time sufficient to fractionate the lignocellulosic material into a solubilized portion containing at least about 20% of the lignin from the lignocellulosic material, and a solid fraction containing cellulose; separating the solubilized portion from the solid fraction, and removing the solubilized portion while at or near reaction temperature; and recovering the solubilized portion.

[0050] Hydrolysis can also comprise contacting a biomass material with stoichiometric amounts of sodium hydroxide and ammonium hydroxide at a very low concentration. See Teixeira et al , 1999, Appl. Biochem. and Biotech. 77-79: 19-34. Hydrolysis can also comprise contacting a lignocellulose with a chemical {e.g. , a base, such as sodium carbonate or potassium hydroxide) at a pH of about 9 to about 14 at moderate temperature, pressure, and pH. See PCT Publication WO 2004/081185.

[0051] Ammonia hydrolysis can also be used. Such a hydrolysis method comprises subjecting a biomass material to low ammonia concentration under conditions of high solids. See, e.g., U.S. Patent Publication No. 20070031918 and PCT publication WO 2006/1 10901.

[0052] Alternatively, biomass hydrolysis can be carried out in the presence of one or more hydrolyzing proteins. Hydrolyzing proteins include cellulases, hemicellulases (including but not limited to xylanases, mannanases, beta-xylosidases), carbohydrate esterases (including but not limited to acetyl xylan esterases and ferulic acid esterases), laccases (which are believed to act on lignin), and non-enzymatic proteins such as swollenins (which are thought to swell the cellulose (non-catalytically and make it more accessible to cellulases). As used herein, the term hydrolyzing proteins refers to a single protein, preferably an enzyme (yet more preferably a cellulase or hemicellulase) or a cocktail of different proteins, including one or more enzymes (preferably a cellulase and/ or hemicellulase) and optionally one or more non-enzymatic proteins such as swollenins. The hydrolyzing proteins can have naturally occurring or engineered polypeptide sequences.

[0053] The fermentable sugars used to produce ethanol can also be produced through hydrolysis of starch from starchy cereal crops such as maize, sorghum or wheat or from the extraction of sucrose from sucrose based crops such as sugarcane or sugar beet. Examples of enzymes used for the hydrolysis of starch include a-amylase, β-amylase, saccharifying a-amylase , Glucoamylase and Pillulanase. These enzymes are produced by various sources of bacteria or fungi including B.

licheniformis, Aspergillus oryzae, B. Subtilis, A. nigex, and B. acidopullulyticus .

[0054] Following hydrolysis, the hydrolyzed product typically comprises a mixture of acid or base, partially degraded biomass and fermentable sugars, particularly where acid or ammonia hydrolysis methods are used. Prior to further processing, the acid or base can be removed from the mixture by applying a vacuum. The mixture can also be neutralized prior to detoxification. 6.2 Transition Metal Catalysts

[0055] The methods of the disclosure are carried out in the presence of a transition metal catalyst comprising a Group VIII transition metal and a polydentate nitrogen donor ligand. The transition metal catalysts are prepared using a source of a Group VIII metal (see Section 5.2.1) and a polydentate nitrogen donor ligand (see Section 5.2.2).

[0056] The transition metal catalysts described herein are capable of catalyzing the conversion of lower alcohols to higher alcohols. The transition metal catalyst can be formed in situ without isolation or can be pre- formed prior to the conversion of the lower alcohol to the higher alcohol. The catalytic conversions of lower alcohols to higher alcohols can be performed in the presence of a base.

[0057] In embodiments where the transition metal catalyst is formed in situ, the molar ratio between the source of the Group VIII transition metal and the polydentate nitrogen donor ligand is typically between 1 : 10 and 10: 1, and more typically is between 1 : 2 and 1 : 1. The source of the Group VIII transition metal catalyst is typically added or present in an amount of 0.005 mol% to about 1 mol % relative to the first alcohol, or about 0.01 mol% to about 0.5 mol% relative to the first alcohol, or about 0.05 mol% to about 0.25 mol% relative to the first alcohol. If a base is added, the molar ratio between the source of a Group VIII metal and the base is typically between 1 : 1 and 1 : 1000, and more typically between 1 : 1 and 1 : 100. The source of the Group VIII transition metal, polydentate nitrogen donor ligand and base can be added in any order, separately or together in the process reactor.

[0058] In other embodiments, the transition metal catalyst can be pre-formed and isolated prior to conversion of the lower alcohol to the higher alcohol. In such embodiments, the method can include the step of reacting the source of the Group VIII transition metal (Section 5.2.1) and polydentate nitrogen donor ligand (Section 5.2.2) to form a catalyst complex prior to conversion of the alcohol. For instance, the source of a Group VIII transition metal can be reacted with the polydentate nitrogen donor ligand in a suitable solvent. In some embodiments, the transition metal catalyst is in salt form. In these embodiments, the transition metal catalysts contain a non-coordinating counterion such as CI, Br, I, BF₄, PF₆ or SbF₆.

[0059] This pre-formed Group VIII transition metal - nitrogen donor ligand complex {i.e., transition metal catalyst) can then be added to the process reactor. In a similar way, the source of a Group VIII transition metal and/or nitrogen donor ligand or pre-formed Group VIII transition metal— nitrogen donor ligand complex can be pre-reacted with the base and then added to the process reactor. In the case of a batch or semi-batch reaction {see discussion in Section 5.4 below), the addition can be at the beginning of the reaction or can be periodic during the reaction or can be continuous throughout the reaction. In the case of a semi-continuous or continuous reaction, the catalyst can be added at a constant rate or the rate can be varied. In particular the rate of catalyst addition can be used to control reaction rate and/or to modify reaction selectivity. Thus, the rate of catalyst addition can be used to control reaction rate. The rate of catalyst addition can be used to modify reaction selectivity. The rate of catalyst addition can be used to control reaction rate and to modify reaction selectivity.

[0060] In embodiments where the transition metal catalyst is a pre- formed transition metal catalyst, the pre- formed catalyst is typically added in or present in an amount of 0.005 mol% to about 1 mol % relative to the first alcohol, or about 0.01 mol% to about 0.5 mol% relative to the first alcohol, or about 0.05 mol% to about 0.25 mol% relative to the first alcohol, or about 0.05 mol% to about 0.25 mol% relative to the first alcohol; or about 0.10 mol% to about 0.20 mol% relative to the first alcohol. In some embodiments, the pre-formed transition metal catalyst is added at about 0.1 mol% relative to the first alcohol. If a base is added, the molar ratio between the pre-formed transition metal catalyst and the base is typically between 1 : 1 and 1 : 1000, and more typically between 1 : 1 and 1 : 100. For instance, in some embodiments, the base can be added in an amount between about 1 mol% to about 10 mol% relative to the first alcohol. In other embodiments, the base can be added in an amount between about 3 mol% to about 7 mol% relative to the first alcohol. In one such embodiment, the base can be added in an amount of about 5 mol% relative to the first alcohol.

[0061] The optimal transition metal catalyst loading will depend in part on the nature of the catalyst and the reaction conditions employed in performing the catalytic conversions. FIG. 1 shows the percent of ethanol conversion as a function of catalyst loading (mol%) after the reaction was run at 4 hours at a 150^°C in the presence of 5 mol% potassium hydroxide (KOH). [Κ ΐ(η⁵-€₅Η₅)( phen)Cl] (see Section 5.2.2.1) was used as the transition metal catalyst. The optimum conversion of ethanol was achieved at a loading of approximately 0.05% transition metal catalyst.

[0062] The transition metal catalysts of the disclosure typically have a turnover number (TON) exceeding 100 and a turnover frequency (TOF) exceeding 25/hour. TON refers to the total number of moles of ethanol converted to product per mole of catalyst. TOF is TON per hour. In some embodiments, the TON is 200 or greater and the TOF is 50/hour or greater. FIGS. 2 and 3 provide TONs and TOFs for the conversion of ethanol to 1 -butanol using 5 mol% of specific transition metal catalysts of the disclosure after four hours reaction time.

6.2.1 Source of Group VIII Metal

[0063] In particular embodiments, the Group VIII transition metal is selected from one or more of Ru, Fe, and Os. In some embodiments, the Group VIII transition metal comprises Ru. The source of a group VIII metal can be the metal itself in some embodiments. The metal can for example be dispersed on a support material such as carbon, silica or alumina, silica alumina and combinations thereof. Alternatively or in addition, the Group VIII metal can comprise a compound of the metal.

[0064] In other embodiments, the transition metal catalyst can be formed by admixing a transition metal complex with the nitrogen donor polydentate ligand under conditions suitable to coordinate the metal comprising the transition metal complex and at least two nitrogen atoms) and possibly other heteroatoms) of the ligand. In such embodiments, the transition metal complex used to prepare the transition metal catalyst can comprise a component of a complex comprising a species of formula [M(L)_n]_m:

wherein:

(i) M is a Group VIII metal,

(ii) L is a ligand,

(iii) n is an integer from 1 to 8, and

(iv) m is an integer representing the nuclearity of the complex.

[0065] The transition metal complex can be charged. In certain embodiments, M of the complex is one or more of Ru and Fe. In some embodiments, M of the complex is one or more of Ru and Os. In some embodiments, M of the complex is one or more of Fe and Os. In some embodiments, M of the complex is Fe. In some embodiments, M of the complex is Os. In some embodiments, M of the complex is Ru. In particular embodiments, M is Ru. When the overall complex has a charge, the charge will preferably be balanced by a suitable counterion, for example CI, Br, I, BF₄, PF₆, or SbF₆.

[0066] The L groups from [M(L)_n]_m can be the same or different and are ligands, for example chloride, bromide, iodide, hydride, alkoxide, amide, acetate, acetylacetonate, alkyl (for example methyl, ethyl, butyl), amine, ether, a hydrocarbon or substituted hydrocarbon ligand (for example η³- allyl, r|⁴-butadiene, r|⁵-cyclopentadienyl, r|⁶-arene) water, CO, NO, phosphines (for example triphenylphosphine, trimethyl phosphine, trimesityl phosphine or triphenoxyphosphine), pyridine, alcohols, alkenes, alkynes, or V-heterocyclic carbenes. L groups can also be solid state materials that act as ligands and produce a supported metal species, for example silica, alumina, zeolites or poly(vinyl pyridine). Particular ligands include chloride, bromide, iodide, hydride, acetate, acetylacetonate, a hydrocarbon or substituted hydrocarbon ligand (for example r| -allyl, r|⁴-butadiene, r|⁵-cyclopentadienyl, r|⁶-arene), water, CO and phosphines. In forming the transition metal catalyst upon admixing with a polydentate ligand, one or more L groups of the transition metal complex can be displaced.

[0067] In embodiments where the Group VIII metal can comprise a component of a complex comprising a species of formula [M(L)_n]_m, n can be an integer from 1 to 8. In certain embodiments, n is an integer from 2 to 6. In other embodiments, n is an integer from 3 to 5.

[0068] In embodiments where the Group VIII metal of the transition metal complex can comprise a component of a complex comprising a species of formula [M(L)_n]_m, m is an integer representing the nuclearity of the complex. When m=l the complex is a monomer, when m=2 the complex is a dimer, etc. and is generally from 1 to 8, preferably 1 or 2 although other values are possible. Generally the nature and number of the ligands (L) is selected to achieve suitable stability of the complex. A single source of a Group VIII transition metal or a mixture of two or more sources can be used. Suitable sources for Fe and Os metal are known in the art. In particular embodiments, single sources of a Group VIII transition metal can be used. Suitable sources for Ru metal include, for example, one of the following transition metal complexes:

RuCl₃.3H₂0

Rul₃

Ru(acetylacetonate)₃

Ru(PPh₃)₃Cl₂

Ru(PPh₃)₃(H)(CO)Cl

[Ru(C₆H₆)Cl₂]₂

[Ru(arene)Cl₂]₂ (where arene is, for example, benzene or cymene)

Ru(CO)₃Cl₂

[Ru(CO)₄]₃

[0069] In a particular embodiment, the transition metal complex used to form the transition metal catalysts of the disclosure is [Ru(cymene)Cl₂]₂, which has the following chemical structure:

6.2.2 Polydentate Nitrogen Donor Ligand

[0070] The polydentate nitrogen donor ligand comprises at least two nitrogen atoms that are capable of binding to the Group VIII metal of the transition metal catalysts. Ligands in which only the two nitrogen atoms bind to the Group VIII metal are bidentate ligands. In certain embodiments, the ligands can contain other heteroatoms in addition to the two nitrogen atoms that are capable of binding to the Group VIII metal of the transition metal catalyst. For example, three heteroatoms of the polydentate nitrogen donor ligand can bind to the Group VIII metal, thereby forming a tridentate ligand. Alternatively, four heteroatoms of the polydentate nitrogen donor ligand can bind to the Group VIII metal, thereby forming a tetradentate ligand.

6.2.2.1 Polydentate Ligands of Formula (I)

[0071] In certain embodiments, the polydentate ligand is comprised of two 5- or 6- membered nitrogen-containing heterocyclic rings which can be bonded together or linked through a linking group. Such ligands are represented by the Formula (I):

(I)

wherein:

(i) Qi and (¾ are each independently a 5- or 6-membered monocyclic aromatic or non- aromatic heterocyclic ring containing at least one nitrogen atom;

(ii) each (R¹^ and (R²)_b are independently selected from:

(a) halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C2-Cg)alkenyl, -(C2-Cg)alkynyl, and -(Ci-C6)alkoxy; or

(b) the R¹ and R² groups form a (C₂-C₄)bridge that is either saturated or unsaturated, wherein said bridge is unsubstituted or substituted with 1 , 2, 3, or 4 substitutents selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t- butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl;

(iii) a is an integer selected from 0, 1 , 2 and 3;

(iv) b is an integer selected from 0, 1 , 2 and 3;

(v) X is selected from:

(c) a bond

(vi) each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, and phenyl.

[0072] In particular embodiments, Qi and Q₂ are independently selected from pyridinyl, pyrazinyl, pyrimidinyl, triazinyl, piperidinyl, pyrrolidinyl, pyrazolidinyl, imidazolidinyl, isoxazolidinyl, oxazolidinyl, dihydropyrrolyl, dihydropyrazolyl, dihydroimidazolyl, dihydroisoxazolyl, dihydrooxazolyl, dihydrothiazolyl, pyrrolyl, pyrazolyl, imidazolyl, isoxazolyl, oxazolyl and isoindoledionyl. In another embodiment, Qi and (¾ are pyridinyl. In another embodiment, Qi is pyridinyl and (¾ is dihydroisoxazolyl. In another embodiment, Qi is pyridinyl and (¾ is dihydrothiazolyl. In another embodiment, Qi and Q₂ are pyrimidinyl.

[0073] The -(5- or 6-membered)heterocycles Qi and (¾ can be attached to linking group X of Formula (I) via a nitrogen or carbon atom. Alternatively, in embodiments where X is a bond, the -(5- or 6-membered)heterocycles Qi and (¾ can be covalently bonded to each other via two carbon atoms on the respective rings. For instance, in particular embodiments where X is a bond, the ligand can be a 2,2-bipyridine or 2,2-bipyrimidine of Formula IA:

(IA)

where Z is -CH- or -N- a nndd ((RR''))a_a aanndd ((RR²)b aarree ddeeffined as above. Particular examples of 2,2- bipyridine ligands include:

[0074] In other embodiments where R is a bond, the ligand can have the Formula (IB)

(IB) where Z is carbon or nitrogen, (R')_a and (R²)_b are defined as above, and T is sulfur, oxygen of -NH-. Particular examples of the ligand of Formula (IB) include:

[0075] In certain embodiments, X in Formula (I) is present as a heterocyclic group that links rings Qi and Q_2. In particular embodiments, X is 1 ,3-phenylene, 1 ,4-phenylene, 1 ,2-phenylene, 2,5-pyridylene, 2,5-pyridylene, 3,6-pyridylene or 2,5- pyrimidylene or 2,5- pyrimidylene. In some such

embodiments, X is a phenylene group selected from 1 ,2-phenylene, 1 ,4-phenylene and 1,3-phenylene. Particular examples of such ligands include:

[0076] In other embodiments, the R¹ and R² groups of Formula (I) can form a (C₂-C₄)bridge that either saturated or unsaturated. In some such embodiments, R¹ and R² can form an ethylene bridg In one such embodiment, the ligand can be a 1,10-phenantroline compound the Formula (IC):

(IC)

where (R')_a and (R²)_b and are defined as above, R4 is selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl, and c is 0, 1 or 2. Specific Examples of 1,10-phenanthroline ligands of Formula (IC) include:

[0077] Examples of pre- formed complexes in which 1,10- phenanthroline (phen) is used as an exemplar polydentate nitrogen donor ligand include: [Ru(r|⁶-cymene)( phen)Cl]Cl, [Ru(r|⁶-cymene)( phen)Cl]PF₆, [Ru(r|⁶-cymene)( phen)H]PF₆, [Ru^⁵-C₅H₅)( phen)Cl], [Ru(phen)(Cl)^-Cl)]₂, and [Ru(phen)₂Cl₂]. In other embodiments, other ligands described herein could be substituted for the phen ligand.

[0078] In particular embodiments, the pre- formed transition metal catalyst has one of the following chemical structures:

6.2.2.2 Polydentate Ligands of Formula (II)

[0079] In certain embodiments, the polydentate ligand is comprised of a 5- or 6- membered nitrogen- containing heterocyclic ring which is bonded directly or through a linker to an amine donor or imine- type donor. Such ligands are represented by the Formula (II):

wherein:

(i) Qi is a 5- or 6-membered aromatic or non-aromatic heterocyclic ring containing at least one nitrogen atom;

(ii)

is selected from halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n- propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C₂-C₆)alkenyl, -(C₂-C₆)alkynyl, and -(Ci-C₆)alkoxy;

(iii) G is selected from:

(a) -CH₂-, -CH₂OCH₂-, -CH₂CH₂OCH₂CH₂-, -CH-, -CH₂CH₂-, -CH₂CH-,

-CH(R⁵)CH(R⁵)-, CH₂N(R⁵)CH₂-, -CH₂CH₂N(R⁵)CH₂CH₂-, 1 ,3-phenylene, 1 ,4-phenylene,

1 ,2-phenylene, 2,5-pyridylene, 2,5-pyridylene, 3,6-pyridylene or 2,5- pyrimidylene and 2,5- pyrimidylene; or

(b) a bond

(iv) each R⁵ is independently selected from:

(a) hydrogen, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, trimethylsilyl, -C(halo)3, CH(halo)₂, -CH₂(halo), methylsulfonyl, and methylsulfinyl; or

(b) benzyl, phenyl, phenylsulfonyl, phenylsulfinyl, pyridyl, furyl, thiophenyl, pyrrolyl, oxazolyl, imidazolyl, thiazolidinyl, thiadiazolyl, thiazolyl, isoxazolyl, pyrazolyl, isothiazolyl, pyridazinyl, pyrimidinyl, triazinyl, morpholinyl, pyrrolidinonyl, pyrrolidinyl, piperidinyl, piperazinyl, 2,3-dihydrofuranyl, dihydropyranyl, pyridinyl, pyrazinyl, pyrazolidinyl, imidazolidinyl, isoxazolidinyl, oxazolidinyl, dihydropyrrolyl,

dihydropyrazolyl, dihydroimidazolyl, dihydroisoxazolyl, dihydrooxazolyl, dihydrothiazolyl, pyrazolyl, imidazolyl, and isoindoledionyl, which can be substituted with one or more R³ groups;

(v) each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, and phenyl; (vi) a is 0, 1 or 2; and

(vii) y is 1 or 2.

[0080] The value of y determines the unsaturation of the nitrogen on the polydentate nitrogen donor ligand. When y is 2, the nitrogen is a fully saturated amine donor, for example dimethylamino if both R¹ groups are methyl. When y is 1, the nitrogen is unsaturated and forms a double bond with G, yielding an imine-type donor of the type -N=C-.

[0081] In some embodiments, the polydentate nitrogen donor ligand can have the Formula (IIA):

where (R')_a, G, R⁵ and y are defined as above. Specific Examples of ligands of Formula (IIA) include:

[0082] In some embodiments, the polydentate nitrogen donor ligand can have the Formula (ΠΒ):

(IIB) where (R')_a, ⁵ and y are defined as above. Specific Examples of ligands of Formula (IIB) include:

6.2.2.3 Polydentate Ligands of Formula (III)

[0083] In certain embodiments, the polydentate ligand is a ligand of Formula (III):

(R⁵)_yN G N(R⁵)_y

(III)

[0084] wherein:

(i) each R⁵ is independently selected from:

(a) hydrogen, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, trimethylsilyl, -C(halo)₃, -CH(halo)2, -CH₂(halo), methylsulfonyl, and methylsulfinyl; and

(ii) G is -CH₂-, -CH₂OCH₂-, -CH₂CH₂OCH₂CH₂-, -CH-, -CH₂CH₂-, -CH₂CH-, -CH(R⁵)CH(R⁵)-, CH₂N(R⁵)CH₂-, -CH₂CH₂N(R⁵)CH₂CH₂-, 1 ,3-phenylene, 1 ,4-phenylene, 1,2- phenylene, 2,5-pyridylene, 2,5-pyridylene, 3,6-pyridylene or 2,5- pyrimidylene and 2,5- pyrimidylene;

(iii) each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl; and

(iv) y is 1 or 2.

[0085] The value of y determines the unsaturation of the nitrogen on the polydentate nitrogen donor ligand. When y is 2, the nitrogen is a fully saturated amine donor, for example dimethylamino if both R¹ groups are methyl. When y is 1, the nitrogen is unsaturated and forms a double bond with G, yielding an imine-type donor of the type -N=C-.

[0086] Specific Examples of ligands of Formula (III) include:

[0087] Other specific Examples of ligands of Formula (III) include ethylenediamine,

di ethyl enetriamine, 1 ,2-diphenylethylenediamine, and N-p-Tosyl-l,2-diphenylethylenediamine.

6.3 Base

[0088] Preferably the base's conjugate acid has a pKa greater than 5. The base can comprise any compound with a conjugate acid having a pKa preferably greater than 5. Suitable bases include metal alkoxides (such as NaOMe, KOMe, NaOEt, NaOBu), metal hydroxides, amines and metal carbonates, or basic solid-state materials. In particular embodiments, the base is a metal alkoxide or hydroxide. For example, the base can be potassium hydroxide, potassium methoxide, potassium ethoxide and potassium butoxide. These can also be formed in the reaction media by reaction of sodium or potassium metal with an alcohol or water.

[0089] In other embodiments, the Group VIII metal and/or polydentate ligand may fulfill the role of the base. For example, the polydentate ligand may contain a basic functionality within its structure (such as an amine) which has a conjugate acid with a pKa greater than 5.

6.4 Catalytic Conversions of Lower Alcohols to Higher Alcohols

[0090] The catalytic conversions of the disclosure can be can be run as batch, semi -batch or continuous processes. The feed alcohol (lower alcohol) and the prepared catalyst can be fed to a reactor. Where base is added, the addition can be made once during a reaction or periodically or continually. The rate of base addition can be used to control reaction rate and/or reaction selectivity. Thus, the rate of base addition can be used to control reaction rate. The rate of base addition can be used to control reaction selectivity. The rate of base addition can be used to control reaction rate and selectivity. More than one base can be added. The base can be added as a solution in a suitable solvent, for example dissolved in the reactant or in an inert solvent. The base can also be added as a solid. The reaction can be configured so that the process stream containing the catalyst first passes over a solid base in a first zone and subsequently enters a reaction zone where the conversion of the first alcohol to the second alcohol occurs. Alternatively a dissolved base can be mixed with the reactant in a first zone and this is then passed over an immobilized form of the catalyst in a subsequent reaction zone. These configurations can be used in batch or continuous mode.

[0091] The catalytic conversions of the disclosure can be carried in the presence of water without significant attenuation of catalyst activity. The catalytic conversions of the disclosure can be carried out in the presence of 5% v/v water or more and still retain catalytic activity. For instance, in particular embodiments, the conversion of ethanol to 1-butanol using a transition metal catalyst of the disclosure can be carried out in the presence of 5% v/v water, 10% v/v water, 15% v/v water, 20% v/v water or 25% v/v water. In certain embodiments, the amount of water can be bounded by any of the two foregoing embodiments, e.g., between 5% v/v water and 25% v/v water, between 5% v/v water and 20% v/v water, between 5% v/v water and 10% v/v water, between 10% v/v water and 20% v/v water, and so on, and so forth.

[0092] FIG. 4 shows the catalytic conversion of ethanol to 1-butanol as a function of increasing initial water volume after 4 hours reaction of ethanol with 0.1 mol% of the transition metal catalyst [Ru^⁵-C₅H₅)( phen)Cl] and 5 mol% of the base sodium ethoxide (NaOEt) at a temperature of 150°C (see diamond shapes). While the yield of 1-butanol decreases with increasing water volume, the catalysts are still highly active in water. In contrast, diphosphine ligand catalyst (square shapes) described in WO/2012/004572 show a significant reduction of catalytic activity when the reaction is conducted under otherwise identical conditions.

[0093] In the reaction section, the lower alcohol to be converted is intimately contacted with the catalyst of the disclosure, which can be in solid or liquid form. Additional chemicals can be added to promote or moderate the reaction, along with hydrogen and/ or other gas to maintain the required pressure. The reactor design will be appropriate to the form of the catalyst, the phase of the reaction and the need to add or remove heat. Lower alcohols may prefer vapor phase operation or require higher pressure to remain in liquid phase at reaction temperature, while higher alcohols may prefer liquid phase operation or require lower pressure operation to enable vaporization at reaction temperature. Intimate contacting of the reactant and catalyst may be effected naturally (as with the flow of vapor phase reactant through a solid catalyst bed), mechanically by use of an agitator or hydraulically by liquid or vapor jet mixing. The catalyst can be placed in an immobilized form within a distillation column and the reactant allowed to distil through the catalyst bed. A reactive distillation takes place where more volatile reactant passes up the distillation column and reacts. Unreacted alcohol can be removed above the reaction zone and returned lower in the column for further reactive distillation. Product alcohol with lower vapor pressure passes down the distillation column and can be removed lower in the column. This configuration allows for a continuous reaction with high conversion. In another configuration the catalyst, reactant and other materials such as base are mixed in solution and introduced to a reactor. The stream is allowed to react and then leaves the reactor where the reaction is then terminated by cooling or quenching by for example reducing the pH of the stream or by separating reactant from the catalyst.

[0094] The material leaving the reactor can undergo a primary separation in a primary separator to separate the desired product(s) from unreacted feed materials which can then be recycled to the reactor. This primary separation can take a number of forms, including flash separation, distillation, liquid liquid extraction, size selective absorption or adsorption, pressure swing adsorption, membranes or a combination of suitable techniques. Primary separation can also be combined with reaction in a reactive distillation system. Any unreacted feed materials in gas or vapor phase leaving the primary separation can be treated to remove trace contaminants deleterious to the process and/or heated/cooled and/or compressed/pumped to the appropriate conditions for recycle to the reactor.

[0095] In an alternative configuration any dissolved solids such as catalyst or base are fully or partially separated from the stream to give a liquid mixture of product and unreacted feed material which are then separated from each other in a subsequent step.

[0096] A higher boiling solvent can be added prior to the reaction, during it or subsequently, which can then be used to maintain the catalyst system and/or base in solution whist fully or substantially removing the reactant alcohol(s) and the product alcohol(s)

[0097] For some applications it is not necessary to separate the reactants and products. A product stream comprising reactant alcohol(s) and product alcohol(s) is separated from the dissolved solids and gases but is then not further separated. This mixture can be used directly, for example as a fuel composition or can be used as a reactant mixture. By modifying the extent of reaction a balance between production economics and product properties can be achieved.

[0098] In the process reactor, the transition metal catalyst can be in the same phase as the lower alcohol (for example a homogeneous reaction in the liquid phase) or in a different phase (for example a solid catalyst and liquid or gaseous ethanol). The amount of catalyst in the process reactor (based on molar ratio ethanol to the Group VIII transition metal) will vary depending on the specific reactor configuration used but will typically be between 10⁸ and 100 to 1. In a homogeneous reaction, the higher alcohol product can also act as a diluent, or an additional diluent solvent can be added.

Suitable diluents include alkanes (such as butane, pentane, hexane, cyclohexane), arenes (such as benzene, toluene, xylene), alcohols (such as methanol, ethanol, propanol, butanol), ethers (such as diethyl ether, dibutyl ether, tetrahydrofuran), carboxylic acids and carboxylic acid derivatives (such as acetic acid, ethyl acetate), water, or mixture thereof.

[0099] The catalyst system can optionally be used in dissolved form during the reaction period but then recovered in solid form outside the reaction zone and re-solubilized for subsequent use. In another configuration the catalyst can be recovered in its dissolved form by leaving it in contact with a suitable solvent throughout which can be the reactant the product or another solvent. In a further embodiment, the catalyst can be recovered in dissolved form by extracting it from the reaction mixture with a solvent. Process variables such as pH or temperature can be varied to modify catalyst solubility to effect such separations.

[00100] Certain diluents can also be used as entrainers in a reactive distillation configuration so as to be able to remove water from the reactive distillation whilst leaving the reactant alcohol in the distillation column. Cyclohexane for example would be a suitable diluent and entrainer to use with ethanol allowing water to be removed at the top of the reactive distillation column. Removing water in this way can improve reaction rate. In another configuration a diluent can be chosen so that following reaction it then assists in the subsequent separation by breaking azeotropes either with water or between reactants and products.

[0100] Another option is to use a diluent which is the same as a subsequent article of commerce to be produced from the product alcohol or which can be produced from the reactant alcohol in order to obviate the need to then separate the diluent from the reactant or the product. Examples of this approach include using 2-ethylhexyl alcohol as diluent when making 1 -butanol and subsequently using this product to produce 2-ethylhexanol. Similarly butyl acetate could be used and the 1 -butanol product used to make butyl acetate. Ethyl acetate could be used and the residual ethanol be used to produce ethyl acetate.

[0101] The steady state reaction temperature can be between 0 °C and 500 °C, and more typically between 70 °C and 200 °C or between 130 °C and 170 °C. Thus, in some embodiments, the reaction is performed at a temperature between about 131 °C and 170°C; 132°C and 170°C; 133°C and 170°C; 134°C and 170°C; 135°C and 170°C; 140°C and 170°C; 145°C and 170°C; 145°C and 170°C; 150°C and 170°C; 165°C and 170°C; 160°C and 170°C; 165°C and 170°C; 131 °C and 165°C; 132°C and 165°C; 133°C and 165°C; 134°C and 165°C; 135°C and 165°C; 140°C and 165°C; 145°C and 165°C; 145°C and 165°C; 150°C and 165°C; 131 °C and 160°C; 132°C and 160°C; 133°C and 160°C; 134°C and 160°C; 135°C and 160°C; 140°C and 160°C; 145°C and 160°C; 145°C and 160°C; 150°C and 160°C; or 165°C and 160°C. In some embodiments, the catalytic methods of the disclosure are carried out at a temperature between about 145°C and 155°C; 146°C and 154°C; 147°C and 153°; C148°C and 152°C; 149°C and 151 °C. Preferably, the method is carried out at a temperature of about 150°C. The method of the disclosure can be performed under an inert atmosphere, typically argon or hydrogen. The process reaction can be performed under a pressure of hydrogen. Thus, in some embodiments, the process reaction is carried out under a pressure of hydrogen e.g. 0.05, 0.1 , 0.2, 0.3, 0.4, 0.5, 1 , 1.5, 2, 2.5, 3, 3.5, 4, 4.2, 4.5, 5, 10, 15, 20 MPa or higher. In some embodiments, the process reaction is carried out under a pressure of argon e.g. 0.05, 0.1 , 0.2, 0.3, 0.4, 0.5, 1 , 1.5, 2, 2.5, 3, 3.5, 4, 4.2, 4.5, 5, 10, 15, 20 MPa or higher. [0102] The methods of the disclosure can further include the step of separating the higher alcohol product from the reaction composition. The separation can be carried out by any appropriate method, for example by passing the reaction product to a membrane separator. As discussed above, preferably the alcohol product (e.g., 1-butanol) is sufficiently pure that it can be used at least for some applications without further purity being required.

[0103] The process optionally includes a subsequent separation step designed to maximize the recovery of the transition metal catalyst from the process effluent streams. Techniques such as distillation, precipitation, membrane separation, electrolysis, ion exchange and liquid extraction can be used.

[0104] It can be beneficial to integrate the production of the lower alcohol and the catalytic conversion to a higher alcohol into a single integrated process. One such embodiment is depicted schematically in FIG. 6. As shown in FIG 6, hydrolysis of biomass (or starch) results in the production of sugar monomers and oligomers, which can be fermented to a lower alcohol (e.g., ethanol). The lower alcohol is then fed into a reactor along with a transition metal catalyst of the disclosure and a suitable base. Following reaction, the stream leaving the reactor is comprised of a mixture of reactants, impurities and the higher alcohol product. The higher alcohol product can be isolated by using an appropriate separation technique such as flash separation, distillation, or liquid liquid extraction.

[0105] In the case of an integrated process which uses fermentation derived ethanol, it can be important to be able to recover the transition metal catalyst and so fermentation streams with high levels of undissolved solid material cause complications unless the integration is performed in the appropriate way. Therefore in one embodiment the integration can be made by adding the catalytic reactor into the rectification stage of the fermentation process distillation as a reactive distillation zone where solid material is kept in the base of the distillation column and the transition metal catalyst is separated from the solids by a portion of column containing substantially liquid or vapor components. In another embodiment, the catalytic reactor is integrated subsequent to the distillation stage so as to be fed with a substantially solids free process stream.

[0106] The temperature of the catalytic reaction can be significantly higher than the process temperatures of a fermentation process. In one embodiment, this temperature difference can be used to provide heat integration for the ethanol distillation section. In the case of a lignocellulosic ethanol process it can be used to provide heat integration to the pretreatment stage. In a corn or wheat ethanol process it can be used to provide heat integration to the starch liquefaction stage, evaporation and/or the ethanol distillation stage. In a sugarcane ethanol process it can be used to provide heat integration to the evaporation and/or ethanol distillation stage. [0107] Because the lower to higher alcohol process includes its own product separation stage, the integrated process allows a lower separation efficiency in the separation of ethanol from the fermentation broth. For example water need not be so completely removed as in a non integrated ethanol process. Fusel alcohols need not be so completely removed. Other organic components such as furans produced in a lignocellulosic ethanol process need not be so fully removed. These materials can all be subsequently separated in the higher alcohol separation stage.

6.5 Selectivity

[0108] The purity of the second alcohol generated as a product of the catalyzed reaction of the disclosure can reach high levels, for example greater than 80% or 90%. Preferably the reaction products are such that substantially no further reaction and/ or separation of the second alcohol from other reaction products is required.

[0109] In preferred embodiments, the conversion is highly selective giving a high yield of the second alcohol relative to other products, particularly alcohol byproducts. While it is envisaged that the product including the second alcohol can include a mixture of two or more different alcohols, preferably the second alcohol is present as the dominant alcohol product. As used herein, the term "selectivity" refers to the percentage by weight of the second alcohol in the final product based on the weight of all alcohols (excluding the first alcohol) in the conversion products. If the catalytic conversions of the disclosure are run as a batch process, the selectivity may gradually decrease with the extent of conversion as products are formed in the reaction chamber. If the catalytic conversions are performed in a continuous process, the liquid fractions containing the product are continuously removed and hence, selectivity does not vary significantly with extent of conversion.

[0110] In one embodiment involving the catalytic conversion of ethanol to 1-butanol, other alcohol byproducts may form, including 2-ethoxybutanol, hexan-l-ol and 2-ethylhexanol. A selectivity of 90% 1-butanol indicates that 90% of the total alcohol products in 1-butanol. The remaining 10% often comprises a mixture of 2-ethoxybutanol, hexan-l-ol and 2-ethylhexanol.

[0111] In some embodiments, selectivity of at least 80% of the second alcohol can be achieved at a conversion of 20% or greater of the first alcohol. In other embodiments, selectivity of at least 85% of the second alcohol can be achieved at a conversion of 20% or greater of the first alcohol. In particular embodiments, selectivity of at least 90% can be achieved at a conversion of 20% or greater of the first alcohol. For example, the selectivity of the second alcohol produced by methods in accordance with the disclosure can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% at a conversion of 20% or greater of the first alcohol. In certain embodiments, the selectivity of the second alcohol can be bounded by any of the two foregoing embodiments, e.g., a selectivity of between 90% and 95%, a selectivity between 90% and 97%, a selectivity of between 92% and 95%, a selectivity of between 92% and 97%, a selectivity of between 92% and 99%, a selectivity of between 93% and 97%, a selectivity of between 95% and 98%, at a conversion of 20% or greater of the first alcohol.

[0112] FIGS. 2 and 3 show selectivities for the conversion of ethanol to 1-butanol using 5 mol% of specific transition metal catalysts of the disclosure after four hours reaction time.

[0113] As discussed above, FIG. 1 shows the percent of ethanol conversion as a function of catalyst loading (mol%) after the reaction was run at 4 hours at a 150°C in the presence of 5 mol% potassium hydroxide (KOH). [Ru(r|⁵-C₅H₅)( phen)Cl] was used as the transition metal catalyst. FIG. 5 shows the product distribution (i.e., selectivity) at the various catalyst loadings. As shown in FIG. 5, high selectivities were achieved at all levels of catalyst loading, with the optimal selectivities achieved at catalyst loading between about 0.05 mol% and about 0.1 mol%.

It will be understood that any of the preferred features may be combined with one or more of the other preferred features and/or embodiments of the disclosure.

7. EXAMPLES

7.1 General Synthetic Procedures

[0114] For all of the examples described below, the catalytic procedures were performed under an inert atmosphere (Argon or Nitrogen) using degassed and dried reagent-grade solvents unless otherwise stated. Catalyst-screening experiments were performed using a 300ml volume Pan- stainless steel autoclave with stir-bar. Product analysis was performed on a Varian Saturn 2100T GC/MS using a FactorFour capillary column VF-5ms. NMR analysis was performed on an ECP 300MHz spectrometer.

[0115] To perform catalytic conversions, a Group VIII metal source (0.1 mol%), polydentate nitrogen donor ligand (0.1 mol%) (or 0.1mol% of a pre-formed metal-ligand complex) and solid base (5 mol%) were added the autoclave with stir-bar under inert atmosphere. Using standard Schlenk-line techniques, 35mL (599mmol) ethanol was then added with rigorous stirring at room temperature. The reaction vessel was then sealed and mixtures were then heated to 150°C with continued stirring for 4 hours. During this time, the internal pressure of the reaction vessel increased so that in each case the final pressure was between 0.1 and 1.4 MPa. The run was terminated by cooling and release of pressure.

[0116] Conversion is stated as a percentage of maximum possible butanol yield (299mmol) based on the ethanol added. GC/MS analysis was carried out using methanol as a diluent and was calibrated using w-pentanol as a standard. 7.2 Catalytic Conversions with Transition Metal Catalysts Performed In Situ Example 1

[0117] (Cymene)ruthenium dichloride dimer (0.05 mol%), 1,10-phenanthroline (0.1 mol%) and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite (RTM Celite Corporation, US) and analyzed by GC/MS. The GC-trace showed 16.3% conversion to butanol, 89% selectivity. The selectivity was determined by integration of GC signals for butanol compared with all of the other components in the product other than ethanol.

Example 2

[0118] (Cymene)ruthenium dichloride dimer (0.05 mol%), 2,2-bipyridine(0.1 mol%) and sodium ethoxide (5 mol%) were stirred with 35mL ethanol ( 599mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 17.1% conversion, 83.4% selectivity.

Example 3

[0119] (Cymene)ruthenium dichloride dimer (0.05 mol%), terpyridine(0.1 mol%) and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 13.1% conversion, 72.9% selectivity.

Example 4

[0120] (Cymene)ruthenium dichloride dimer (0.05 mol%), 2, 2'-(ethane-l,2- diylbis(azanediyl))diethanol (0.1 mol%), and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 10.2% conversion, 90.9% selectivity.

Example 5

[0121] (Cymene)ruthenium dichloride dimer (0.05 mol%), prolinamide (0.1 mol%) and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 9.4% conversion, 82.1%) selectivity.

Example 6

[0122] (Cymene)ruthenium dichloride dimer (0.05 mol%), (2-amino-l,2-diphenylethyl)(p- tosyl)amide(0.1 mol%) and sodium ethoxide(5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 11.7% conversion, 78.6% selectivity. Example 7

[0123] (Cymene)ruthenium dichloride dimer (0.05 mol%), (E)-2-((pyridine-2- ylmethylene)amino)ethanol (0.1 mol%) and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 13.9% conversion, 84.9% selectivity.

Example 8

[0124] (Cymene)ruthenium dichloride dimer (0.05 mol%), 1,10-phenanthroline (0.1 mol%) and potassium tert-butoxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 18.8% conversion, 87.5% selectivity.

Example 9

[0125] (Cymene)ruthenium dichloride dimer (0.05 mol%), 5 -nitro- 1,10-phenanthroline (0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. GC-trace showed 10.9% conversion, 96.0% selectivity.

Example 10

[0126] (Cymene)ruthenium dichloride dimer (0.05 mol%), 5-amino-l,10-phenanthroline(0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 11.9% conversion, 96.2% selectivity.

Example 11

[0127] (Cymene)ruthenium dichloride dimer (0.05 mol%), 2,4,6,8-tetramethyl-l,10-phenanthroline (0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The Reaction mixture was filtered through Celite and analyzed by GC/MS. The GC- trace showed 13.8% conversion, 95.6% selectivity.

7.3 Synthesis of Pre-Formed Catalysts

[0128] The synthesis of some of the pre-formed catalysts, for example catalyst complexes that can be used in examples of aspects of the invention are now described purely by way of example.

Example 12

[0129] Preparation of Chloro(/?-cymene)(r|²- 1 , 10-phenanthroline- ²/V)ruthenium:

[0130] [RuCl₂(cymene)]₂ was added as a solution in dichloromethane to a solution of 2 equivalents of the ligand 1,10-phenanthroline, also in dichloromethane. The mixture was then stirred at room temperature for 4 hours before the solvent was removed in vacuo, and then dissolved in degassed water to remove excess ligand. The mixture was then filtered to remove the precipitated excess ligand and the water removed in vacuo.

[0131] The analysis by Ή NMR of the product was as follows:

[0132] Ή NMR (D₂0): 59.70 (d, 2H, J=5.30Hz), 58.60 (d, 2H, J=8.52Hz), 57.98 (dd, 2H, j'=8.52Hz, J²=5.30Hz), 57.89 (s, 2H), 52.51 (septet, 1H, J=6.96Hz), 52.1 1 (s, 3H), 50.84 (d, 6H, J=6.96Hz).

Example 13

[0133] Preparation of Chloro(/?-cymene)(r|²- 2,4,6, 8-tetramethyl-l ,10-phenanthroline-K² V)ruthenium: [RuCl₂(cymene)]₂ was added as a suspension in ethanol to a solution of 2 equivalents of the ligand 2,4,6,8-tetramethyl-l ,10-phenanthroline , also in ethanol. The mixture was refluxed for 20 hours before the solvent was removed in vacuo, and then dissolved in dichloromethane. The subsequent solution was precipitated out in hexanes to give a yellow solid. The Product was analyzed by NMR: Ή NMR (300 MHz, CDC1₃) 5 9.82 (s, 2H, H₂, i¾-phen), 8.08 (s, 2H, H₅, 7¾-phen), 6.44 (d, 2H, .7=6.09 Hz, Ar ), 6.24 (d, 2H, .7=6.09, ArH), 2.79 (d, 12H, .7=4.40 Hz, Me₄-phen), 2.67 (sept, 1H, .7=6.89 Hz, C77(CH₃)₂), 2.27 (s, 3H, Me), 0.98 (d, 6H, .7=6.95 Hz, CH(C¾)₂);

Example 14

[0134] Preparation of [RuCl₂(2,2-bipyridine)₂]: To a solution of 2,2-bipyridine (2 equivalents) and lithium chloride (large excess) in dimethylformamide, RuCl₂(DMSO)₄was added, with stirring and the reaction mixture protected from light using aluminum foil. The reaction mixture was refluxed overnight, allowed to cool slightly, then poured into stirring acetone and left to cool in the freezer overnight. The precipitate was collected, washed with water and diethyl ether, and dried under vacuum to give a dark purple solid. The product was analyzed by Ή NMR.

[0135] Ή NMR (400 MHz, DMSO) 59.94 (d, 2H, J=5.16Hz), 58.60 (d, 2H, J=8.00Hz), 58.44 (d, 2H, J=8.00Hz), 58.03 (t, 2H, J=7.57Hz), 57.73 (t, 2H, J=6.50Hz), 57.64 (t, 2H, J=7.57Hz), 57.48 (d, 2H, J=5.33Hz), 57.06 (t, 2H, J=6.50Hz).

7.4 Catalytic Conversions with Pre-Formed Transition Metal Catalysts Example 15

[0136] Chloro(/7-cymene)(η²-l ,10-phenant^lroline- ² V)ruthenium (0.1 mol%) and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 16.6% conversion, 90.2% selectivity.

Example 16

[0137] Chloro(/7-cymene)(η²-l ,10-phenant^lroline- ² V)ruthenium (0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 20% conversion, 95.1% selectivity.

Example 17

[0138] Chloro(/7-cymene)(η²-l ,10-phenanthroline- ² V)ruthenium (0.1 mol%) and potassium hydroxide (10 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 23.6% conversion, 86.0% selectivity.

Example 18

[0139] [RuCl₂(2,2-bipyridine)₂] and sodium ethoxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 20 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 26.6% conversion, 92.3% selectivity.

Example 19

[0140] Chloro(/7-cymene)(η²-2,4,6,8-tetramethyl-l ,10-phenanthroline- ² V)ruthenium (0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 21.5% conversion, 95.0% selectivity.

Example 20

[0141] Chloro(/7-cymene)(l ,10-phenanthroline)ruthenium (0.1 mol%) and sodium hydroxide (5 mol%) were stirred with 35mL Ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 12.8% conversion, >99% selectivity.

Example 21

[0142] Chloro(/7-cymene)(l ,10-phenanthroline)ruthenium (0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) and 1.83mL water (102 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC-trace showed 1 1.1% conversion, 95.0% selectivity.

Example 22

[0143] Essentially the same procedure as Example 21 was followed, only with varying amounts of added water (see FIG. 4). In all cases selectivity was higher than 90% and conversion to 1-butanol is indicated in the graph.

Example 23

[0144] Chloro(/ cymene)(TsDEPN)ruthenium (TsDEPN = N-p-Tosyl- 1 ,2- diphenylethylenediamine) (0.1 mol%) and potassium hydroxide (5 mol%) were stirred with 35mL ethanol (599 mmol) for 4 hours at 150°C. The reaction mixture was filtered through Celite and analyzed by GC/MS. The GC- trace showed 9% conversion, 88% selectivity.

Comparative Example

[0145] Essentially the same procedure as Examples 21 and 22 was followed, only with bis(diphenylphosphino)methane (a bidentate phosphine ligand) in place of 1,10-phenanthroline (a polydentate nitrogen ligand). Conversion to 1-butanol is indicated in FIG. 4 and shows that the polydentate nitrogen donor ligand of Example 22 gives higher conversion after 4 hours reaction time when water is added compared to a bidentate phosphine ligand.

[0146] Features of aspects of the invention have been described above by way of example only and variations may be made within the scope of the invention.

EMBODIMENTS OF THE INVENTION

1. A method for converting a lower alcohol to a higher alcohol comprising the step of contacting said lower alcohol with a transition metal catalyst comprising a Group VIII transition metal complexed to a polydentate nitrogen donor ligand for a time sufficient to form said higher alcohol.

2. The method of embodiment 1, wherein the lower alcohol comprises 2 carbon atoms.

3. The method of embodiment 2, wherein the lower alcohol is ethanol.

4. The method of embodiment 1, wherein the lower alcohol comprises 3 carbon atoms.

5. The method of embodiment 1, wherein the lower alcohol comprises 4 carbon atoms.

6. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

3 carbon atoms.

7. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

4 carbon atoms

8. The method of any one of embodiments 1-6 or 8, wherein the higher alcohol is an isomer of butanol.

9. The method of embodiment 8, wherein the higher alcohol is 1 -butanol.

10. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

5 carbon atoms.

11. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

6 carbon atoms.

12. The method of embodiment 11, wherein the higher alcohol is hexan-l-ol.

13. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

7 carbon atoms.

14. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

8 carbon atoms.

15. The method of any one of the preceding embodiments, wherein the higher alcohol comprises

9 carbon atoms. 16. The method of any one of the preceding embodiments, wherein the higher alcohol comprises 10 carbon atoms.

17. The method of any one of the preceding embodiments, wherein the transition metal is Ru, Fe or Os.

18. The method of embodiment 17, wherein the transition metal is Ru.

19. The method of embodiment 17, wherein the transition metal is Fe.

20. The method of embodiment 17, wherein the transition metal is Os.21. The method of any one of the preceding embodiments, wherein the polydentate ligand is a bidentate ligand.

22. The method of any one of embodiments 1-20, wherein the polydentate ligand is a tridentate ligand.

23. The method of any one of embodiments 1-21 , wherein the polydentate ligand is a tetradentate ligand.

24. The method of any one of the preceding embodiments, wherein the polydentate ligand is a ligand of Formula (I):

(I)

wherein:

(ii) each (R¹^ and (R²)_b are independently selected from:

(a) halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec -butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C2-Cg)alkenyl, -(C2-Cg)alkynyl, and -(Ci-C6)alkoxy; or

(b) the R¹ and R² groups form a (C₂-C₄)bridge that is either saturated or unsaturated, wherein said bridge is unsubstituted or substituted with 1, 2, 3, or 4 substitutents selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t- butyl, sec -butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl;

(iii) a is an integer selected from 0, 1, 2 and 3;

(iv) b is an integer selected from 0, 1, 2 and 3;

(v) X is selected from:

(a) methylene, ethylene, ethenylene, or propylene, ethynediyl, sulfur, and oxygen; or

(c) a bond

each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, and phenyl.

25. The method of embodiment 24, wherein the ligand has the Formula (IC):

(IC) wherein R₄ is selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl and c is an integer selected from 0, 1 and 2.

26. The method of embodiment 25, wherein the ligand is:

The method of embodiment 25, wherein the ligand is:

The method of embodiment 25, wherein the ligand is:

The method of embodiment 25, wherein the ligand i

The method of embodiment 25, wherein the ligand is:

The method of embodiment 25, wherein the ligand is:

The method of embodiment 24, wherein the ligand has the Formula (IA)

(IA)

wherein Z is -CH- or -N-.

The method of embodiment 32, wherein the ligand i

The method of embodiment 32, wherein the ligand

The method of embodiment 32, wherein the ligand

The method of embodiment 32, wherein the ligand i

The method of embodiment 24, wherein the ligand has the Formula (IB):

(IB)

wherein Z is -CH- or -N- and T is or -0-, -S-, or -NH-

The method of embodiment 36, wherein the ligand i

The method of embodiment 36, wherein the ligand

The method of embodiment 36, wherein the ligand i

The method of embodiment 36, wherein the ligand i

The method of embodiment 32, wherein the transition metal catalyst is:

42. The method of embodiment 32, wherein the transition metal catalyst is:

43. The method of embodiment 32, wherein the transition metal catalyst is:

44. The method of any one of embodiments 1-23, wherein the polydentate ligand is a ligand of Formula (II):

(II)

wherein:

(i) Qi is a 5- or 6-membered monocyclic heterocyclic ring containing at least one nitrogen atom which is either saturated non-aromatic, unsaturated non-aromatic or aromatic;

(ii) (R')_a is selected from halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n- propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C₂-C₆)alkenyl, -(C₂-C₆)alkynyl, and -(Ci-C₆)alkoxy; (iii) G is selected from:

(b) a bond

(iv) each R⁵ is independently selected from:

(a) hydrogen, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, trimethylsilyl, -C(halo)₃, -CH(halo)₂, -CH₂(halo), methylsulfonyl and methylsulfinyl; and

(v) each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, and phenyl;

(vi) a is 0, 1 or 2; and

(vii) y is 1 or 2.

The method of embodiment 44, wherein the ligand has the Formula (ΠΑ):

(Rⁿ

IIA

The method of embodiment 45, wherein the ligand is:

47. The method of embodiment 45, wherein the ligand is:

The method of embodiment 45, wherein the ligand

49. The method of any one of embodiments 1-23, wherein the polydentate ligand is a ligand of Formula (III):

(R⁵)_yN G N(R⁵)_y

(III) wherein:

(i) each R⁵ is independently selected from:

(a) hydrogen, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, trimethylsilyl, -C(halo)₃, -CH(halo)₂, -CH₂(halo), methylsulfonyl, and methylsulfinyl; and

(iii) each R³ is independently selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl; and (iv) y is 1 or 2.

50. The method of embodiment 49, wherein the ligand is:

Ph N N Ph

51. The method of embodiment 49, wherein the ligand is:

H,C— -N N CH₃

52. The method of embodiment 49, wherein the ligand is:

I I C N CH ;

CH3 CH3

53. The method of embodiment 49, wherein the ligand is:

54. The method of embodiment 49, wherein the ligand is ethylenediamine.

55. The method of embodiment 49, wherein the ligand is diethylenetriamine.

56. The method of embodiment 49, wherein the ligand is 1 ,2-diphenylethylenediamine

57. The method of embodiment 49, wherein the ligand is N-p-Tosyl- 1 ,2- diphenylethylenediamine.

58. The method of any one of the preceding embodiments, wherein the transition metal catalyst is formed in situ by admixing a source of the Group VIII transition metal with the polydentate nitrogen donor ligand in the presence of the lower alcohol.

59. The method of embodiment 58, wherein the nitrogen donor ligand is 1 ,10-phenanthroline. 60. The method of embodiment 58, wherein the nitrogen donor ligand is 2,2-bipyridine.

61. The method of embodiment 59, wherein the nitrogen donor ligand is terpyridine.

62. The method of embodiment 58, wherein the nitrogen donor ligand is 2,2 '-(ethane- 1,2- diylbis(azanediyl))diethanol.

63. The method of embodiment 58, wherein the nitrogen donor ligand is prolinamide.

64. The method of embodiment 58, wherein the nitrogen donor ligand is 2-amino-l,2- diphenylethyl)(p-tosyl)amide.

65. The method of embodiment 58, wherein the nitrogen donor ligand is (E)-2((pyridine-2- ylmethylene)amino)ethanol.

66. The method of embodiment 58, wherein the nitrogen donor ligand is 5-nitro-l,10- phenanthroline.

67. The method of embodiment 58 , wherein the nitrogen donor ligand is 5-amino- 1,10- phenanthroline.

68. The method of embodiment 58, wherein the nitrogen donor ligand is 2,4,6,8-tetramethyl-l,10- phenanthroline.

69. The method of embodiment 58, wherein the source of the Group VIII transition metal is RuCl₃.3H₂0,

70. The method of embodiment 58, wherein the source of the Group VIII transition metal is Rul₃, Ru(acetylacetonate)₃

71. The method of embodiment 58, wherein the source of the Group VIII transition metal is Ru(PPh₃)₃Cl₂

72. The method of embodiment 58, wherein the source of the Group VIII transition metal is Ru(PPh₃)₃(H)(CO)Cl

73. The method of embodiment 58, wherein the source of the Group VIII transition metal is [Ru(QH₆)Cl₂]₂

74. The method of embodiment 58, wherein the source of the Group VIII transition metal is [Ru(cymene)Cl₂]₂ 75. The method of embodiment 58, wherein the source of the Group VIII transition metal is Ru(benzene)Cl2]2

76. The method of embodiment 58, wherein the source of the Group VIII transition metal is Ru(CO)₃Cl₂

77. The method of embodiment 58, wherein the source of the Group VIII transition metal is [Ru(CO)₄]₃.

78. The method of any one of the preceding embodiments , wherein the source of the Group VIII transition metal is [Ru(cymene)Ci2]2-

79. The method of any one of embodiments 1-57, wherein the transition metal catalyst is preformed prior to said contacting with said lower alcohol.

80. The method of embodiment 79, wherein the pre- formed transition metal catalyst is Chloro( - cymene)(r|²- 1 , 10-phenanthroline-K² V)ruthenium.

81. The method of embodiment 79, wherein the pre- formed transition metal catalyst is Chloro( - cymene)(r|²- 2,4,6, 8-tetramethyl- 1 , 10-phenanthroline- ² V)ruthenium.

82. The method of embodiment 79, wherein the pre-formed transition metal catalyst is

[RuCl₂(2,2-bipyridine)₂] .

83. The method of embodiment 79, wherein the pre-formed transition metal catalyst is Chloro(/ cymene)(r|²-2,4, 6, 8-tetramethyl- 1 , 10-phenanthroline-K²jV)ruthenium.

84. The method of embodiment 79, wherein the pre-formed transition metal catalyst is Chloro(/ cymene)( 1 , 10-phenanthroline)ruthenium.

85. The method of embodiment 79, wherein the pre-formed transition metal catalyst is Chloro(/ cymene) (TsDEPN)ruthenium (TsDEPN = N-/?-Tosyl-l,2-diphenylethylenediamine).

86. The method of embodiment 79, wherein the pre-formed transition metal catalyst is bis(diphenylphosphino) methane.

87. The method of any one of embodiments 79-86, wherein the pre-formed catalyst is a salt.

88. The method of any one of the preceding embodiments, wherein said contacting step is carried out in the presence of a base.

89. The method of embodiment 88, wherein the base is a metal alkoxide base.

90. The method of embodiment 89, wherein the base is sodium ethoxide 91. The method of embodiment 89, wherein the base is potassium methoxide.

92. The method of embodiment 91 , wherein the base is potassium ethoxide.

93. The method of embodiment 91 , wherein the base is potassium butoxide.

94. The method of embodiment 91 , wherein the base is potassium tert-butoxide.

95. The method of embodiment 88, wherein the base is a metal hydroxide base.

96. The method of embodiment 95, wherein the base is potassium hydroxide.

97. The method of embodiment 95, wherein the base is sodium hydroxide.

98. The method of any one of embodiments 88-97, wherein the molar ratio of the source of a Group VIII metal and the base is between 1 :40 and 1 :60

99. The method of any one of embodiments 88-97, wherein the molar ratio of the source of a Group VIII metal and the base is 1 :50 and 1 : 150

100. The method of any one of the preceding embodiments, wherein said contacting is carried out at a temperature between 70°C and 200°C.

101. The method of embodiment 100, wherein said contacting is carried out at a temperature between 140°C and 160°C.

102. The method of embodiment 100 or 101 , wherein said contacting is carried out at a temperature of about 150°C.

103. The method of any one of the preceding embodiments, wherein the method is carried out under an inert atmosphere

104. The method of claim 103, wherein the method is carried out under nitrogen.

105. The method of claim 103, wherein the method is carried out under argon.

106. The method of any one of embodiments 103-105, wherein the inert atmosphere has a partial pressure of 0.05MPa or higher.

107. The method of embodiment 106, wherein the inert atmosphere has a partial pressure of between 0.1 and 1.4 MPa. 108. The method of any one of the preceding embodiments, wherein the reaction mixture comprises at least 5% water by volume.

109. The method of any one of the preceding embodiments, wherein the reaction mixture comprises at least 10% water by volume.

110. The method of any one of the preceding embodiments , further comprising producing said ethanol prior to said contacting step.

111. The method of embodiment 110, wherein the ethanol is produced by a biosynthetic process.

112. The method of embodiment 111, wherein the biosynthetic process comprises fermenting one or more fermentable sugars.

113. The method of embodiment 110 or embodiment 111 , wherein said biosynthetic process is carried out by fermenting microorganism in a medium comprising said fermentable sugars under conditions in which the fermenting microorganism produces the ethanol.

114. The method of embodiment 113, wherein the fermenting microorganism is yeast.

115. The method of embodiment 113, wherein the fermenting microorganism is bacteria.

116. The method of any one of embodiments 112-115, wherein the one or more fermentable sugars are selected from glucose, mannose, galactose and xylose.

117. The method of any one of embodiments 112-116, wherein said fermenting comprises hydrolyzing a lignocellulosic biomass.

118. The method of embodiment 117, wherein the hydrolyzing is carried out in the presence of a dilute acid.

119. The method of embodiment 117, wherein the hydrolyzing is carried out in the presence of at least one hydrolyzing protein.

120. The method of embodiment 119, wherein said at least one hydrolyzing protein is a cellulase enzyme.

121. The method of embodiment 119, wherein said at least one hydrolyzing protein is a hemicellulase enzyme.

122. The method of any one of embodiments 118-121, wherein the lignocellulosic biomass comprises one or more of Napier grass, energy cane, sorghum, giant reed, sugar beet, switchgrass, bagasse, rice straw, miscanthus, switchgrass, wheat straw, wood, wood waste, paper, paper waste, agricultural waste, municipal waste, birchwood, oat spelt, corn stover, eucalyptus, willow, hybrid poplar, short-rotation woody crop, conifer softwood, crop residue.

123. The method of any one of the preceding embodiments, wherein the transition metal catalyst is in the same phase as the lower alcohol.

124. The method of any one of embodiments 1-122, wherein the transition metal catalyst is in a different phase from the lower alcohol.

125. The method of any one of the preceding embodiments, further comprising separating the higher alcohol from the reaction mixture.

126. The method of any one of the preceding embodiment, wherein the higher alcohol undergoes a further processing step.

127. The method of embodiment 126, wherein the further processing step comprises converting the higher alcohol to an alkene.

128. The method of any one of the preceding embodiments, wherein the higher alcohol is 1- butanol, the method comprising a further processing step of converting said 1-butanol to 2- ethylhexanol.

129. The method of embodiment 128, comprising a further step of producing a plasticizer.

130. The method of embodiment 129, wherein the plasticizer is 2-ethylhextl phthalate.

131. The method of any one of the preceding embodiments, wherein the higher alcohol is 1 - butanol, the method comprising a further processing step of converting said 1-butanol to 1- butyylacetate.

132. The method of any one of the preceding embodiments, wherein the higher alcohol is 1- butanol, the method comprising a further processing step of converting said 1-butanol to ethyl acetate.

133. The method of any one of the preceding embodiments, wherein the higher alcohol is 1- butanol, the method comprising a further processing step of converting said 1-butanol to hexan-l-ol.

134. The method of any one of the preceding embodiments, wherein the higher alcohol is 1- butanol, the method comprising a further processing step of converting said 1-butanol to 2-ethylbutan- l-ol. 135. The method of any one of the preceding embodiments, wherein the higher alcohol is 1- butanol, the method comprising a further processing step of converting said 1-butanol to 1-octanol.

136. The method of any one of the preceding embodiments, wherein the higher alcohol is 1- butanol, the method comprising a further processing step of converting said 1-butanol to 2- ethylhexan-l-ol.

137. The method of any one of embodiments 57-58 or embodiments 88-136, wherein the molar ratio between the source of the Group VIII transition metal and the polydentate nitrogen donor ligand is between 1 : 10 and 10: 1.

138. The method of embodiment 137, wherein the molar ratio between the source of the Group VIII transition metal and the polydentate nitrogen donor ligand is between 1 :2 and 1 : 1.

139. The method of any one of the preceding embodiments, wherein the source of the Group VIII transition metal catalyst is added or present in an amount of about 0.005 mol% to about 1 mol % relative to the first alcohol.

140. The method of embodiment 139, wherein the source of the Group VIII transition metal catalyst is added or present in an amount of about 0.01 mol% to about 0.5 mol% relative to the first alcohol.

141. The method of embodiment 140, wherein the source of the Group VIII transition metal catalyst is added or present in an amount of about 0.05 mol% to about 0.25 mol% relative to the first alcohol.

142. The method of any one of the preceding embodiments, wherein the lower alcohol is formed from pre-cursor acetaldehyde.

143. The method of any one of the preceding embodiments comprising a step of forming the lower alcohol from acetaldehyde.

144. The method of any one of embodiments 1-141, wherein the lower alcohol is formed from precursor alkene.

145. The method of embodiment 144, wherein the pre-cursor alkene is ethylene.

146. The method of any one of embodiments 1-141 or 144 or 145 comprising a step of forming the lower alcohol from alkene. 147. The method of any one of embodiments 1-141 or 144-146, comprising a step of forming the lower alcohol from ethylene.

148. Use of a transition metal catalyst comprising a Group VIII transition metal complexed to a polydentate nitrogen donor ligand in a method for producing a higher alcohol from a lower alcohol, wherein the reaction mixture comprises at least 5% water by volume.

149. The use of embodiment 148, wherein the reaction mixture comprises at least 10% water by volume.

150. The use of embodiment 149, wherein the reaction mixture comprises at least 15% water by volume.

151. The use of embodiment 150, wherein the reaction mixture comprises at least 20% water by volume.

152. The use of embodiment 151, wherein the reaction mixture comprises at least 25% water by volume.

153. The use of any one of embodiments 148 to 152, wherein the Group VIII transition metal complexed to a polydentate nitrogen donor ligand is as defined in any one of embodiments 17 to 68.

Claims

WHAT CLAIMED IS:

2. The method of claim 1 , wherein the transition metal is Ru, Fe or Os.

3. The method of claim 2, wherein the transition metal is Ru.

4. The method of claim 2, wherein the transition metal is Fe.

5. The method of claim 2, wherein the transition metal is Os.

6. The method of any one of claims 1-5, wherein the transition metal catalyst is formed in situ by admixing a source of the Group VIII transition metal with the polydentate nitrogen donor ligand in the presence of the lower alcohol.

7. The method of claim 6, wherein the source of the Group VIII transition metal is selected from RuCl₃.3H₂0, Rul₃, Ru(acetylacetonate)₃, Ru(PPh₃)₃Cl₂, Ru(PPh₃)₃(H)(CO)Cl,

[Ru(C₆H₆)Cl₂]₂, [Ru(cymene)Cl₂]₂, Ru(benzene)Cl₂]₂, Ru(CO)₃Cl₂ or [Ru(CO)₄]₃.

8. The method of claim 7, wherein the source of the Group VIII transition metal is [Ru(cymene)Cl₂]₂.

9. The method of any one of claims 1-5, wherein the transition metal catalyst is preformed prior to said contacting with said lower alcohol.

10. The method of claim 9, wherein the pre-formed catalyst is a salt.

1 1. The method of any one of claims 1-10, wherein the polydentate ligand is a bidentate ligand.

12. The method of any one of claims 1-10, wherein the polydentate ligand is a tridentate ligand.

13. The method of any one of claims 1-10, wherein the polydentate ligand is a tetradentate ligand.

14. The method of any one of claims 1-13, wherein the polydentate ligand is a ligand of Formula (I):

(ii) each (R¹^ and (R²)_b are independently selected from:

(a) halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec -butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C₂-C₆)alkenyl, -(C₂-C₆)alkynyl, and -(Ci-C₆)alkoxy; or

(iii) a is an integer selected from 0, 1 , 2 and 3;

(iv) b is an integer selected from 0, 1 , 2 and 3;

(v) X is selected from:

(c) a bond

15. The method of claim 14, wherein the ligand has the Formula (IC):

(IC) wherein R4 is selected from halo, cyano, hydroxyl, nitro, amino, aminoalkyl, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl and phenyl and c is an integer selected from 0, 1 and 2.

16. The method of claim 15, wherein the ligand is selected from:

17. The method of claim 16, wherein the ligand is:

(IA) wherein Z is -CH- or -N-

19. The method of claim 18, wherein the ligand is selected from:

20. The method of claim 14, wherein the ligand has the Formula (IB):

(IB)

wherein Z is -CH- or -N- and T is or -0-, -S-, or -NH-

21. The method of claim 20, wherein the ligand is selected from:

The method of claim 18, wherein the transition metal catalyst is selected from:

23. The method of any one of claims 1-13, wherein the polydentate ligand is a ligand of Formula (II):

(II)

wherein:

(i) Q I is a 5- or 6-membered monocyclic heterocyclic ring containing at least one nitrogen atom which is either saturated non-aromatic, unsaturated non-aromatic or aromatic;

(ii) (R')_a is selected from halo, cyano, hydroxyl, nitro, amino, methyl, ethyl, isopropyl, n- propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, benzyl, phenyl, ortho-tolyl, meta-tolyl, para-tolyl, isopropylphenyl, dimethylphenyl, mesityl, naphthyl, -(C₂-C₆)alkenyl, -(C₂-C₆)alkynyl, and -(Ci-C₆)alkoxy;

(iii) G is selected from:

(b) a bond

(iv) each R⁵ is independently selected from:

(vi) a is 0, 1 or 2; and

(vii) y is 1 or 2.

24. The method of claim 23, wherein the ligand has the Formula (ΠΑ):

IIA

25. The method of claim 24, wherein the ligand is selected from:

26. The method of any one of claims 1-13, wherein the polydentate ligand is a ligand of Formula (III):

(R⁵)_yN G N(R⁵)_y

(III) wherein:

(i) each R⁵ is independently selected from:

(a) hydrogen, methyl, ethyl, isopropyl, n-propyl, t-butyl, sec-butyl, isobutyl, n-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, trimethylsilyl, -C(halo)3, -CH(halo)₂, -CH₂(halo), methylsulfonyl, and methylsulfinyl; and

(b) benzyl, phenyl, phenylsulfonyl, phenylsulfmyl, pyridyl, furyl, thiophenyl, pyrrolyl, oxazolyl, imidazolyl, thiazolidinyl, thiadiazolyl, thiazolyl, isoxazolyl, pyrazolyl, isothiazolyl, pyridazinyl, pyrimidinyl, triazinyl, morpholinyl, pyrrolidinonyl, pyrrolidinyl, piperidinyl, piperazinyl, 2,3-dihydrofuranyl, dihydropyranyl, pyridinyl, pyrazinyl, pyrazolidinyl, imidazolidinyl, isoxazolidinyl, oxazolidinyl, dihydropyrrolyl,

(iv) y is 1 or 2.

27. The method of claim 26, wherein the ligand is selected from:

28. The method of claim 26, wherein the ligand is selected from ethyl enediamine, diethyl enetriamine, 1 ,2-diphenylethylenediamine, and V-/?-Tosyl-l,2-diphenylethylenediamine.

29. The method of any one of claim 1-28, wherein said contacting step is carried out in the presence of a base.

30. The method of claim 29, wherein the base is a metal alkoxide base.

31. The method of claim 30, wherein the base is selected from potassium methoxide, potassium ethoxide and potassium butoxide.

32. The method of any one of claims 1-31, wherein said contacting is carried out at a temperature between 70°C and 200°C.

33. The method of any one of claims 1-32, wherein the reaction mixture comprises at least 5% water by volume.

34. The method of any one of claims 1-32, wherein the reaction mixture comprises at least 10% water by volume.

35. The method of any one of claims 1-34, further comprising separating the higher alcohol from the reaction mixture.

36. The method of any one of claims 1-35, further comprising converting the higher alcohol to an alkene.

37. The method of any one of claims 1-36, wherein the higher alcohol is an isomer of butanol.

38. The method of any one of claims 1-37, wherein the higher alcohol is 1 -butanol.

39. The method of any one of claims 1-38, wherein the lower alcohol is ethanol.

40. The method of claim 39, further comprising producing said ethanol prior to said contacting step.

41. The method of claim 40, wherein the ethanol is produced by a biosynthetic process.

42. The method of claim 41 , wherein the biosynthetic process comprises fermenting one or more fermentable sugars.

43. The method of claim 41 or claim 42, wherein said biosynthetic process is carried out by fermenting microorganism in a medium comprising said fermentable sugars under conditions in which the fermenting microorganism produces the ethanol.

44. The method of claim 43, wherein the fermenting microorganism is yeast or bacteria.

45. The method of any one of claims 42-44, wherein the one or more fermentable sugars are selected from glucose, mannose, galactose and xylose.

46. The method of any one of claims 42-45, wherein said fermenting comprises hydrolyzing a lignocellulosic biomass.

47. The method of claim 46, wherein the hydrolyzing is carried out in the presence of a dilute acid.

48. The method of claim 46, wherein the hydrolyzing is carried out in the presence of at least one hydrolyzing protein.

49. The method of claim 48, wherein said at least one hydrolyzing protein is a cellulase enzyme.

50. The method of claim 48, wherein said at least one hydrolyzing protein is a hemicellulase enzyme.

51. The method of any one of claims 47-50, wherein the lignocellulosic biomass comprises one or more of Napier grass, energy cane, sorghum, giant reed, sugar beet, switchgrass, bagasse, rice straw, miscanthus, switchgrass, wheat straw, wood, wood waste, paper, paper waste, agricultural waste, municipal waste, birchwood, oat spelt, corn stover, eucalyptus, willow, hybrid poplar, short-rotation woody crop, conifer softwood, crop residue

52. The method of any one of claims 1-51, wherein the transition metal catalyst is in the same phase as the lower alcohol.

53. The method of any one of claims 1-51, wherein the transition metal catalyst is in a different phase as the lower alcohol.