JP6458473B2 - Process for producing lactones - Google Patents

Description

In the present invention, one or more compounds selected from dicarboxylic acid, dicarboxylic acid anhydride and dicarboxylic acid ester (hereinafter, these may be collectively referred to as “dicarboxylic acids”, and “dicarboxylic acid anhydride and dicarboxylic acid ester” Are collectively referred to as “dicarboxylic acid derivatives”.). Specifically, the present invention relates to a method for producing a corresponding lactone by hydrogenation reaction of dicarboxylic acids using biomass resources as raw materials and controlling the saccharide concentration in the reaction mixture during the hydrogenation reaction within a predetermined range.
Lactones are useful as industrial solvents, cleaning agents, and reaction intermediates for polymer chemicals.

  As a method for producing lactones, a method is known in which a dicarboxylic acid is hydrogenated to obtain a corresponding lactone as described above. For example, JP-A No. 64-25771 discloses γ-butyrolactone (hereinafter sometimes referred to as “GBL”) by using succinic anhydride as a raw material and performing a hydrogenation reaction using a ruthenium-based catalyst. Manufacturing is described (Patent Document 1).

  Here, as an industrial production method of dicarboxylic acids used as a raw material, a catalytic oxidation method using a petroleum resource as a raw material is common. However, from the viewpoint of the recent rise in the price of petroleum resources and consideration for the environment, the use of biomass has attracted attention as a raw material that can replace petroleum resources. For example, JP 2010-1007007 discloses dicarboxylic acids and carboxylic acids by fermentation of sugars. A method for producing the derivative is disclosed (Patent Document 2). For example, JP-T-2013-523736 discloses a method for producing GBL by hydrogenation reaction of a dicarboxylic acid obtained by fermentation and a derivative thereof. (Patent Document 3).

  In the production of dicarboxylic acids by fermentation, saccharides are generally used as a raw material, and usually glucose, sucrose, cellulose, or the like is used. However, in the production methods of these dicarboxylic acids, there are cases where polysaccharides are contained as impurities in the dicarboxylic acids to be produced, or unreacted saccharides are mixed.

Japanese Patent Laid-Open No. 64-25771 JP 2010-1007007 A Special table 2013-523736 gazette

  The present invention has a problem that, in the process for producing lactones using raw materials derived from biomass resources as described above, the reaction activity may decrease, and the yield of lactones as products becomes unstable. The object of the present invention is to provide an industrially advantageous process capable of stably obtaining lactones with a high yield.

As a result of intensive studies to solve the above problems, the inventors of the present invention have promoted the lactonization reaction of dicarboxylic acids while the saccharides in the raw materials, particularly monosaccharides and disaccharides, especially monosaccharides, on the other hand, the content thereof Has been found to cause reaction inhibition when above a certain level.
That is, the inventors have found that a lactone can be obtained in a high yield by setting the saccharide concentration in the reaction mixture in the hydrogenation reaction within a predetermined range, thereby completing the present invention.

The gist of the present invention resides in the following [1] to [8].
[1] In the method for producing a corresponding lactone by hydrogenation reaction of a dicarboxylic acid and / or a derivative thereof (hereinafter collectively referred to as “dicarboxylic acids”) obtained from a raw material derived from biomass resources, the hydrogenation reaction The manufacturing method of lactone which makes the sum total density | concentration of the monosaccharide and disaccharide in the reaction mixture of time to 10 mass ppm or more and less than 3000 mass ppm.
[2] The process for producing lactones according to 1 above, wherein the total concentration of monosaccharides and disaccharides is 20 mass ppm or more and 1000 mass ppm or less.
[3] The hydrogenation reaction is carried out using a heterogeneous catalyst and / or a homogeneous catalyst containing a metal belonging to Groups 8 to 11 of the periodic table. [4] The process for producing lactones according to 1 or 2 above [4] The method for producing lactones according to 3 above, wherein the metal belonging to Groups 8 to 11 of the periodic table is ruthenium and / or copper.
[5] The method for producing lactones according to 4 above, wherein the catalyst is a ruthenium complex having an organophosphorus compound as a ligand.
[6] The process for producing a lactone according to any one of 1 to 5 above, wherein the dicarboxylic acid is succinic acid and / or a derivative thereof.
[7] A method for producing a corresponding lactone obtained from a raw material derived from biomass resources by a hydrogenation reaction of dicarboxylic acids has a reaction step, a purification step, and a catalyst circulation step from the purification step to the reaction step, A method for producing lactones, wherein the total concentration of monosaccharides and disaccharides in the reaction mixture in the reaction step is in the range of 20 mass ppm to 1000 mass ppm.
[8] The lactone according to 7 above, wherein in the catalyst circulation step, solvent distillation treatment and catalyst extraction treatment are sequentially performed, and the total amount of monosaccharides and disaccharides circulated to the reaction step during the extraction treatment is adjusted. Manufacturing method.

  According to the present invention, when producing the corresponding lactones by hydrogenation of dicarboxylic acids, by controlling the total concentration of monosaccharides and disaccharides in the reaction mixture during the hydrogenation reaction, high yields are achieved. Lactones can be stably obtained, and an industrially advantageous process capable of producing lactones stably for a long period is constituted.

It is the figure which showed an example of the manufacturing process of lactones of this invention.

  Embodiments of the present invention will be described in detail below, but the following description is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. Moreover, the lower limit value or the upper limit value in this specification means a range including the value of the lower limit value or the upper limit value, respectively.

1. Dicarboxylic acids as lactone raw materials In the present invention, dicarboxylic acids and / or dicarboxylic acid derivatives (“dicarboxylic acids”) are used as raw materials for the production of lactones (hereinafter sometimes simply referred to as “lactones”). Here, the dicarboxylic acid derivative means a dicarboxylic acid anhydride and / or a dicarboxylic acid ester. These raw materials may be used alone or in a mixture.

Although it does not specifically limit as dicarboxylic acid of the dicarboxylic acid of this invention, Aromatic dicarboxylic acid or aliphatic dicarboxylic acid is mentioned.
Specifically, examples of the aromatic dicarboxylic acid include phthalic acid, 2,3-naphthalenedicarboxylic acid, 1,2-naphthalenedicarboxylic acid, 4-methylphthalic acid, 3-methylphthalic acid, trimellitic acid, and the like. Of these, phthalic acid, 4-methylphthalic acid, and 3-methylphthalic acid are preferably used.

  As the aliphatic dicarboxylic acid, a linear or branched saturated or unsaturated dicarboxylic acid having 1 to 17, preferably 2 to 7 carbon atoms in the main chain is suitable. Specifically, oxalic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, malic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 2-oxoglutaric acid, cis-aconitic acid, dodecanediate Examples thereof include maleic acid, fumaric acid, and succinic acid, and succinic acid is particularly preferable.

In addition, as a raw material for the production of lactones, salts of these dicarboxylic acids can also be used, and examples thereof include ammonium salts, sodium salts, potassium salts, calcium salts and the like, and among them, ammonium salts are preferable. "
Moreover, as above-mentioned, in addition to the said various dicarboxylic acid, corresponding acid anhydride and ester can also be used in this invention. As the ester, a linear alkyl ester having 1 to 4 carbon atoms is preferable, and dicarboxylic acid dimethyl ester and dicarboxylic acid diethyl ester are particularly preferable.

2. Production of Dicarboxylic Acids by Biomass Method The dicarboxylic acids used in the present invention are produced by a method of producing biomass resources through a fermentation process (hereinafter sometimes referred to as “bio-method”). The bio-processed product contains monosaccharides and disaccharides, and by controlling the total concentration of these, the hydrogenation reaction of dicarboxylic acids can be promoted, and lactones can be obtained in high yield. It is.

  Suitable biomass resources for use in the present invention include, for example, wood, rice straw, rice husk, rice bran, old rice, corn, sugar cane, cassava, sago palm, okara, corn cob, tapioca cass, bagasse, vegetable oil scum, cocoon, buckwheat, Examples include plant-derived resources such as soybeans, fats and oils, waste paper, and papermaking residues, animal-derived resources such as marine product residues and livestock excrement, and mixed resources such as sewage sludge and food waste, among which plant resources are preferred. Among plant resources, wood, rice straw, rice husk, old rice, corn, sugar cane, cassava, sago palm, straw, oil and fat, waste paper, and papermaking residue are preferable, and corn, sugar cane, cassava, and sago palm are particularly preferable.

  Carbon sources derived from the above biomass resources include hexoses such as glucose, mannose, galactose, fructose, sorbose, tagatose; pentoses such as arabinose, xylose, ribose, xylulose, ribulose; maltose, sucrose, lactose, trehalose Disaccharides and polysaccharides such as starch and cellulose; butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, monoctinic acid, Fatty acids such as arachidic acid, eicosenoic acid, arachidonic acid, behenic acid, erucic acid, docosapentaenoic acid, docosahexaenoic acid, lignoceric acid, ceracolic acid; glycerin, mannitol, xylitol, ribitol, etc. Examples include fermentable sugars such as polyalcohols. Among these, hexoses such as glucose, mannose, galactose, fructose, sorbose, tagatose; pentoses such as arabinose, xylose, ribose, xylulose, ribulose; maltose, sucrose, lactose Disaccharides and polysaccharides such as trehalose, starch, and cellulose are preferable. Among these, glucose, maltose, fructose, sucrose, lactose, trehalose, and cellulose are preferable.

Dicarboxylic acids can be obtained from the above various carbon sources by fermentation using microbial conversion. Examples of microorganisms that can be used for this purpose include coryneform bacteria, Bacillus bacteria, Rhizobium bacteria, and Mycobacterium bacteria, with coryneform bacteria being preferred.
The reaction temperature, pressure, and other reaction conditions during microbial conversion by the fermentation method depend on the activity of microorganisms such as selected cells and molds, and may be appropriately selected according to the purpose.

3. Impurities (sugar content) in biodicarboxylic acids
The dicarboxylic acids produced from the biomass resources may contain saccharides remaining without being utilized (utilized) by microorganisms. In the method for producing lactones of the present invention, polysaccharides remaining without being assimilated by microorganisms may be decomposed into monosaccharides or disaccharides in the raw material dicarboxylic acids.

In the present invention, “monosaccharides and disaccharides” refer to the above-mentioned saccharides derived from biomass resources and derivatives thereof, specifically, compounds having a polyhydroxyketone or a polyhydroxyaldehyde skeleton.
That is, the monosaccharide and disaccharide referred to in the present application have two or more hydroxy groups and one or more aldehyde groups or ketone groups.

  Specific examples of these monosaccharides and disaccharides include hexoses such as glucose, mannose, galactose, fructose, sorbose and tagatose; pentoses such as arabinose, xylose, ribose, xylulose and ribulose; maltose, sucrose, lactose and trehalose. Can be mentioned. Glucose, xylose, maltose, fructose, sucrose, lactose, trehalose and the like are preferable.

In addition, the sugar derivative is not particularly limited as long as it is a compound derived from the above-mentioned sugar, but for example, deoxy sugars such as deoxyribose, fucose, fucose, rhamnose, quinobose, and paratose; sorbitol, mannitol, xylitol, etc. Sugar alcohols; sugar dehydrogenates such as gluconolactone; single-molecule dehydrates such as levoglucosan and 4-deoxy-3-hexosulose; or the reaction product of the above sugar and carboxylic acid.
Such sugar derivatives may be by-produced during sugar fermentation.
4). Formation reaction of lactones

(1) Effect of monosaccharides and disaccharides on the reaction According to the method for producing lactones of the present invention, dicarboxylic acids synthesized by a petrochemical method, for example, containing neither monosaccharides nor disaccharides are used in the reaction system. The lactones can be obtained in a higher yield than the conventional lactone production method.

The reason is not clear, but it is considered that sugar acts on free water, thereby controlling the water concentration in the reaction system and acting on the catalyst to bring about stabilization. The action mechanism is estimated as follows.
Monosaccharides and disaccharides have a high affinity for moisture in the reaction mixture because the proportion of hydrophilic hydroxyl groups is large relative to the proportion of hydrophobic hydrocarbon groups. Therefore, it is considered that the monosaccharide and disaccharide capture the free water in the reaction mixture, thereby having a function of controlling the concentration of free water in the system. If there is too much free water, the equilibrium between the dicarboxylic acid and the dicarboxylic anhydride in the reaction mixture moves to the “acid” side, and the concentration of the highly reactive dicarboxylic anhydride decreases, so the reaction rate decreases. On the other hand, if the free moisture is excessively reduced, the concentration of the dicarboxylic acid that is a nucleophilic ligand in the reaction mixture is remarkably lowered, and the activity of the hydrogenation catalyst is lowered.

A small amount of sugar is coordinated to the hydrogenation catalyst and stabilized, but if the amount of sugar is too large, the coordination field of the hydrogenation catalyst is occupied and the catalytic activity may be reduced. .
That is, by controlling the total concentration of monosaccharides and disaccharides in the reaction mixture within the range specified in the present invention, the concentration of free water is controlled to a concentration suitable for the hydrogenation reaction, and at the same time, the activity of the hydrogenation catalyst is increased. It is considered that the lactone can be stabilized, the lactonization reaction is accelerated, and the lactone can be obtained in a high yield.

Polysaccharides of trisaccharides and higher are coordinated to hydrogenation catalysts because they have a lower affinity with water than monosaccharides and disaccharides, and have a smaller effect on the free water concentration in the reaction mixture, and the greater steric hindrance. Because it is difficult to do so, it does not affect the lactonization reaction so much.
Hereinafter, the sugar concentration used in the hydrogenation of the present invention, the catalyst, and the reaction conditions for the hydrogenation will be described in detail.

(2) Sugar concentration in reaction mixture In the reaction mixture in the production method of the present invention, monosaccharides and / or disaccharides are contained in a total concentration of 10 mass ppm or more and less than 3000 mass ppm. The lower limit of the total concentration of both is preferably 20 ppm by mass or more, and the upper limit is preferably 1000 ppm by mass or less, more preferably 100 ppm by mass or less.

When the total concentration of monosaccharides and disaccharides is less than the above lower limit, the rate of lactonization reaction becomes slow and the yield tends to decrease. On the other hand, when the total concentration of monosaccharides and disaccharides is too high, reaction inhibition is caused and reaction activity tends to decrease.
The concentration of monosaccharides and disaccharides in the reaction mixture can be measured by a method such as high performance liquid chromatography analysis. As a method for maintaining the concentration within the predetermined range of the present application, if the concentration falls below the lower limit, the amount of high-boiling components discharged from the system in the circulation process is reduced or the monosaccharide or disaccharide is added to the reaction system. Can be added directly, hydrolyzing polysaccharides in the circulating fluid to produce monosaccharides and disaccharides, or using raw material succinic acid containing higher concentrations of saccharides, while the concentration is limited to the upper limit. If the value exceeds the value, the amount of high boiling point components released from the system in the circulation process is increased, the saccharides in the circulating fluid are separated by crystallization or extraction, the saccharides are decomposed by heating, and the saccharide content is increased. Examples of the method include using a raw material succinic acid with a low amount or diluting the reaction system with purified lactones.

In the method of the present invention, it is preferable that the total concentration of monosaccharides and disaccharides in the reaction mixture is always maintained within the above range throughout the reaction period (from the start of operation to the stop of operation), but at least 50% or more thereof The total concentration of the monosaccharide and the disaccharide is maintained within a predetermined range in a period of preferably 70% or more, more preferably 80% or more, further preferably 90% or more, and particularly preferably 95% or more. desirable.
Since there is no accumulation of saccharides in the reaction system at the beginning of the operation, it is simply the saccharide concentration in the raw material mixture, and it may not reach the total concentration of monosaccharides and disaccharides of the present invention. It is taken into consideration.

(3) Catalyst The hydrogenation catalyst used in the present invention preferably contains at least one metal selected from metals belonging to Groups 8 to 11 of the periodic table. Examples of the Group 8-11 transition metal include iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, and gold, among which ruthenium and copper are preferable in terms of catalytic activity. Ruthenium having a high catalytic activity is particularly preferable.

The catalyst may be in the form of a solid catalyst or a complex catalyst, but a complex catalyst is preferred in order to obtain higher quality lactones.
Hereinafter, a ruthenium complex catalyst will be described as an example. As the raw material of the catalyst, both metal ruthenium and ruthenium compounds can be used.
As the ruthenium compound, an oxide, a hydroxide, an inorganic acid salt, an organic acid salt, a complex compound, or the like is used. Specifically, ruthenium dioxide, ruthenium tetroxide, ruthenium dihydroxide, ruthenium chloride, ruthenium bromide, ruthenium iodide, ruthenium nitrate, ruthenium acetate, tris (acetylacetonato) ruthenium, sodium hexachlororuthenate, tetracarbonylruthenate Dipotassium, pentacarbonylruthenium, cyclopentadienyldicarbonylruthenium, dibromotricarbonylruthenium, chlorotris (triphenylphosphine) hydridoruthenium, tetra (triphenylphosphine) dihydridolthenium, tetra (trimethylphosphine) dihydrodorenium, bis (tri -N-butylphosphine) tricarbonylruthenium, dodecacarbonyltetrahydridotetraruthenium, dodecacarbonyltrilute Examples thereof include cesium, octadecacarbonyl hexaruthenate dicesium, undecacarbonyl hydridotriruthenate tetraphenylphosphonium, and the like, preferably ruthenium chloride, tris (acetylacetonato) ruthenium, and ruthenium acetate.

  As a ligand of the ruthenium complex catalyst used in the present invention, a phosphorus ligand is preferable. As the phosphorus ligand, those having an aryl group such as triphenylphosphine, diphenylmethylphosphine and dimethylphenylphosphine can be used, but trialkylphosphine, particularly primary alkyl having a phosphorus atom bonded to a primary carbon. A trialkylphosphine constituted by a group or a decomposition product thereof is preferred.

As for carbon number of the alkyl group of such a trialkyl phosphine, about 1-12 are preferable. The three alkyl groups need not all be the same, and they may all be different, or the two may be the same and one may be different, or all may be the same.
Examples of such phosphines include tridecanylphosphine, trinonylphosphine, trioctylphosphine, triheptylphosphine, trihexylphosphine, tripentylphosphine, tributylphosphine, tripropylphosphine, triethylphosphine, trimethylphosphine, dimethyloctylphosphine Dioctylmethylphosphine, dimethylheptylphosphine, diheptylmethylphosphine, dimethylhexylphosphine, dihexylmethylphosphine, dimethylheptylphosphine, diheptylmethylphosphine, dimethylhexylphosphine, dihexylmethylphosphine, dimethylbutylphosphine, dibutylmethylphosphine, tripentylphosphine , Tricyclohexylphosphine, triheptylphos Fin, tribenzylphosphine, dimethylcyclohexylphosphine, dicyclohexylmethylphosphine, 1,1,2,2-dimethylphosphinoethane, 1,1,2,2-dimethylphosphinopropane, 1,1,2,2-dimethylphosphine Finobutane, 1,1,2,2-dioctylphosphinoethane, 1,1,2,2-dioctylphosphinopropane, 1,1,2,2-dioctylphosphinopropane, 1,1,2,2- Dioctylphosphinobutane, 1,1,2,2-dihexylphosphinoethane, 1,1,2,2-dihexylphosphinopropane, 1,1,2,2-dihexylphosphinobutane, 1,1,2, 2-dibutylphosphinoethane, 1,1,2,2-dibutylphosphinopropane, 1,1,2,2-dibutylphosphinobu 1,1-diphosphinane, 1,4-dimethyl-1,4-diphosphane, 1,3-dimethylphosphorinane, 1,4-dimethylphosphorinane, 8-methyl-8-phosphinobicyclooctane, 4, Examples thereof include monophosphites such as -methyl-4-phosphatetracyclooctane, 1-methylphosphorane, and 1-methylphosphonan, bidentate, cyclic, and alkylphosphines having a substituent on the alkyl group.

As the phosphorus ligand, not only the above phosphine but also phosphite, phosphinate, phosphine oxide, aminophosphine, phosphinic acid and the like can be used. These phosphorus ligands are used in an amount of 0. 1 mole per 1 mole of ruthenium metal. 1-1000
The molar range is preferably 1 to 100 mol.
In addition, the ruthenium complex catalyst used in the present invention can be used for the reaction in the form of a cationic complex using a conjugate base of an acid having a pKa of less than 2. Use of a conjugated base is effective in this respect. As the conjugate base of an acid having a pKa of less than 2, any conjugate base may be used as long as it forms such a conjugate base during catalyst preparation or in the reaction system. Or the like.

  Specifically, inorganic acids such as nitric acid, perchloric acid, borohydrofluoric acid, hexafluorophosphoric acid, fluorosulfonic acid, trichloroacetic acid, dichloroacetic acid, trifluoroacetic acid, dodecylsulfonic acid, octadecylsulfonic acid, trifluoromethanesulfonic acid Bronsted acids such as benzene sulfonic acid, paratoluene sulfonic acid, tetra (pentafluorophenyl) boronic acid, organic acid such as sulfonated styrene-divinylbenzene copolymer, alkali metal salts of these acids, alkaline earth metals Examples thereof include salts, ammonium salts, and silver salts.

Further, the above acid conjugate base may be added in the form of an acid derivative that is considered to be produced in the reaction system. For example, the same effect can be expected even if it is added to the reaction system in the form of acid halide, acid anhydride, ester, acid amide or the like.
The amount of these acids or salts thereof used is 1000 mol or less, preferably 100 mol or less, based on the ruthenium metal. 10 mol or less is particularly preferable.

(4) Solvent Production of lactones by the method of the present invention can be carried out using the reaction raw material and reaction product mixture as a solvent, and other solvents and the like do not inhibit the purpose and progress of the reaction to which the method of the present invention is applied. As long as it can be used.
Examples of such solvents include ethers such as diethyl ether, anisole, tetrahydrofuran, ethylene glycol dimethyl ether, and dioxane; alcohols such as methanol, ethanol, n-butanol, benzyl alcohol, phenol, ethylene glycol, and diethylene glycol; formic acid, Carboxylic acids such as acetic acid, propionic acid and toluic acid; esters such as methyl acetate, butyl acetate and benzyl benzoate; aromatic hydrocarbons such as benzene, toluene, ethylbenzene and tetralin; n-hexane, n-octane and cyclohexane Aliphatic hydrocarbons; halogenated hydrocarbons such as dichloromethane, trichloroethane and chlorobenzene; nitro compounds such as nitromethane and nitrobenzene; N, N-dimethylformamide, N Carboxylic acid amides such as N-dimethylacetamide and N-methylpyrrolidone; Hexamethylphosphoric triamide and other amides; Ureas such as N, N-dimethylimidazolidinone; Sulfones such as dimethylsulfone; Sulfoxides such as dimethylsulfoxide Lactones such as caprolactone; polyethers such as tetraglyme and triglyme; carbonates such as dimethyl carbonate and ethylene carbonate, and the like. Preferred are ethers, polyethers, and lactones.

(5) Reaction conditions The hydrogenation reaction carried out by the method of the present invention can be carried out either continuously or batchwise. The reaction temperature is usually 50 to 250 ° C, preferably 100 to 250 ° C, more preferably 150 to 220 ° C. The hydrogen partial pressure in the reaction system is not particularly limited, but is usually 0.01 to 10 MPa · G (gauge pressure, the same shall apply hereinafter) in industrial implementation, and preferably 0.03 to 5 MPa · G. . From the reaction product liquid, lactones which are target products are separated by ordinary separation means such as distillation and extraction.

The water content in the reaction system is preferably 0.01 to 5% by mass, more preferably 0.1 to 5% by mass.
1% by mass. If there is too much water, the equilibrium between the dicarboxylic acid and its anhydride moves to the dicarboxylic acid side, so the dicarboxylic acid anhydride concentration decreases and the lactone production rate decreases. If the water content is too low, the concentration of the dicarboxylic acid serving as the counter anion of the ruthenium catalyst is lowered, and the cationicity of the catalyst is lowered. Therefore, the hydrogenation activity of the catalyst is lowered.

  For removing water from the reaction system, gas stripping or the like can be used. Depending on the reaction process, water may be removed by distillation or a dehydrating agent may be added. When hydrogen is used for gas stripping, the dicarboxylic acid component can be lactonized simultaneously with the removal of water in the reaction solution, which is efficient.

(6) Lactones to be produced In the method of the present invention, lactones can be produced by the procedure as described above.
Specific examples of lactones to which the method of the present invention can be applied are compounds corresponding to the above-mentioned raw material dicarboxylic acids, and most preferred examples include succinic acid, succinic anhydride or succinic acid ester or a mixture thereof as a raw material. Γ-butyrolactone (GBL).

5. Purification of lactones The lactones obtained by the reaction method of the present invention can be purified by general operations such as extraction, distillation, and crystallization after completion of the reaction to obtain highly purified lactones.
In addition to the unreacted raw dicarboxylic acid, the residue after separation of lactones by these purification operations contains monosaccharides, disaccharides and other saccharides contained in the raw materials. . The concentration of monosaccharides and disaccharides in the reaction mixture can be controlled by discharging some of them out of the system and circulating some of them in the reaction system.

  Hereinafter, γ-butyrolactone (GBL) is used as an example to explain the method for purifying lactones according to the steps of distillation-extraction-catalyst circulation, but unless otherwise specified, the object is not limited to GBL. Further, the order of the above processes, the batch / continuous system, the type of individual processing equipment, and the like are not limited to those described below unless they depart from the gist thereof.

(1) Distillation step Separation and purification of the target product from the reaction solution or reaction mixture can be carried out by a conventional method using a distillation method. Depending on the type of solvent used in the reaction, a vacuum distillation method is employed. May be.
In the reaction mixture, in addition to the target product lactones, unreacted dicarboxylic acid components, catalysts, solvents, high-boiling components such as sugars, impurities in raw materials, and by-products purified during the reaction Since low-boiling components are contained, these are separated by distillation.
The above distillation can be performed by using a single distillation column to extract lactones from the middle column of the distillation column. Usually, however, a plurality of stages are preferred for reasons such as stability of operation, column height of the distillation column, and other reasons. Is preferably carried out in a two-stage distillation column. Hereinafter, distillation purification of lactones will be described by taking as an example the case of using a two-stage distillation column.

(First distillation column)
An example of a purification step that can be used in the method of the present invention is shown in FIG.
From the reaction mixture taken out from the reactor of FIG. 1, unreacted dicarboxylic acids, catalysts, solvents, saccharides, and the like, which are components having a higher boiling point than the lactone, are removed in the first distillation column.
Lactones taken out from the top of the distillation column are supplied to the second distillation column, and high-boiling components are discharged from the bottom of the column. This high boiling point component is supplied to the extractor.
The first distillation column used for distilling the lactone is preferably a distillation column having a theoretical plate number of 3 or more and 100 or less, more preferably 5 or more and 50 or less. If the number of theoretical plates is too small, the purity of the target product lactone tends to decrease. If the number of theoretical plates is too large, the amount of heat required for distillation increases, which is not economical.

  The reflux ratio can be adjusted according to the desired purified lactone purity, but is usually preferably 0.01 or more and 100 or less, more preferably 0.1 or more and 50 or less. The pressure at the top of the column is also adjusted according to the type of lactone. For example, in the case of GBL, the absolute pressure is preferably 1 kPa · A or more and 200 kPa · A or less, more preferably 2 kPa · A or more, 100 kPa · A or less, still more preferably 5 kPa · A or more and 50 kPa · A or less. The temperature at the bottom of the column is preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and particularly preferably 120 ° C. or higher and 230 ° C. or lower.

  If the pressure at the top of the column is too high or the temperature at the bottom of the column is too low, the yield of the lactone, which is the target product, tends to be insufficient and the yield decreases. If the temperature at the bottom of the column is too high, not only will the purity of the purified lactone to be obtained be reduced, but also the hydrogenation catalyst may be modified and saccharides may be exothermic and decomposed, making it difficult to operate stably. There is a case.

(Second distillation tower)
The distillate obtained in the first distillation column may be commercialized as a purified lactone as it is, but as shown in FIG. 1, in the second distillation column that removes components having a lower boiling point than the lactone, It is preferable to purify.
There is no particular restriction on the site for recovering the lactone from the second distillation column, but usually the raw material supplied here is the lactone from which the high-boiling components have been removed in the first distillation column, so the lactone is recovered from the bottom of the column. It is common to do.

The second distillation column is preferably a distillation column having a theoretical plate number of 3 or more and 100 or less, more preferably 5 or more and 50 or less. If the number of theoretical plates is too small, the purity of the lactones decreases and the significance of using the second distillation column is reduced. If the number of theoretical plates is too large, the amount of heat required for distillation increases, which is not economical.
Similar to the first distillation column, the reflux ratio can be adjusted according to the desired purified lactone purity, for example, 0.01 or more and 100 or less, preferably 0.1 or more and 50 or less. Although the tower top pressure is also adjusted depending on the type of lactone, for example, in the case of GBL, the absolute pressure is preferably about 1 kPa · A to 200 kPa · A, more preferably 2 kPa · A to 100 kPa · A. Particularly preferred is 5 kPa · A or more and 50 kPa · A or less. The temperature at the bottom of the column is preferably 20 ° C. or higher and 250 ° C. or lower, more preferably 50 ° C. or higher and 230 ° C. or lower, and particularly preferably 80 ° C. or higher and 200 ° C. or lower.

If the pressure at the top of the column is too high or the temperature at the bottom of the column is too low, the purity of the target lactone tends to be insufficient, and the pressure at the top of the column is too low or the temperature at the bottom of the column is too high. This increases the amount of heat required for distillation, which not only is not economical, but also reduces the yield of purified lactone.
Although not shown in FIG. 1, the lactone recovered from the second distillation column may be further distilled.

  As described above, the distillation operation in these distillation towers may be either batch type or continuous type, but continuous distillation is preferable from the viewpoint of productivity. The distillation method may be simple distillation or multi-stage distillation, but from the viewpoint of separation performance, multi-stage distillation is preferable, and the form of the distillation tower may be a plate tower or a packed tower packed with regular and / or irregular packing. Either can be used.

(2) Extraction step In the above distillation step, the catalyst contained in the liquid (hereinafter sometimes referred to as “catalyst liquid”) obtained by distilling the lactones as the target product from the reaction liquid or reaction mixture, The reaction dicarboxylic acid, solvent, saccharide and the like may be circulated as they are to the reaction step, but at least a part of the catalyst solution is separated by extraction treatment, and the component circulated to the reaction system and the component discharged outside the system It is preferable to separate them into As the solvent used for the extraction of the catalyst solution, it is preferable to use a polar solvent and a nonpolar organic solvent.

  In the example of the extraction process using the extractor shown in FIG. 1, after extracting the catalyst in the catalyst solution with a nonpolar solvent, the solvent is distilled off and the remaining catalyst is circulated. The extraction residual liquid (polar solvent phase) contains saccharides, unreacted dicarboxylic acid, or reaction by-products. The extraction residual liquid may be discharged out of the system, but the dicarboxylic acids and the like contained therein may be recycled after being removed by a separation operation such as distillation. In the extraction step, a third phase other than the nonpolar solvent phase and the polar solvent phase may exist. In this case, the third phase may be discharged out of the system, but it is circulated together with the nonpolar solvent phase, or a component such as dicarboxylic acids is extracted by heating or hydrolysis in the presence of a catalyst. Later, it can also be circulated.

  Prior to the extraction operation, it is preferable to distill away the solvent from the catalyst solution because the liquid separation property is often improved. When the solvent is distilled off from the catalyst solution, the amount of the organic solvent remaining in the solution after the distillation is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less. is there. The residual solvent amount is most preferably 1% by mass or less, and particularly preferably 0% by mass.

  As the polar solvent, a solvent having a dielectric constant (ε) at 20 ° C. of 15 or more, preferably 20 or more and a boiling point of 50 to 150 ° C. is used. For example, water, methanol, ethanol, propanol, butanol, etc. Lower alcohols; ketones such as acetone and methyl ethyl ketone, and the like. Water or lower alcohols are preferably used from the viewpoint of economy and safety.

  As the nonpolar organic solvent, a solvent having a dielectric constant (ε) at 20 ° C. of 6 or less, preferably 4 or less, and a boiling point of 50 to 200 ° C., preferably 50 to 150 ° C. may be used. , Aliphatic hydrocarbons such as hexane, heptane, octane, decane, aromatic hydrocarbons such as benzene, toluene, xylene, diethylbenzene, isopropylbenzene (cumene), diethyl ether, propyl ether, butyl ether, ethyl phenyl ether, methyl Ethers such as phenyl ether (anisole), oxanes such as 1,4-dioxane and 1,3,5-trioxane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, halogenated carbonization such as dichloromethane, trichloroethane and chlorobenzene Examples include hydrogen.

The temperature during the extraction operation is usually selected from the range of 0 to 150 ° C, preferably 20 to 100 ° C. If the temperature is too low, the extraction efficiency tends to decrease due to a decrease in solubility or an increase in liquid viscosity. If the temperature is too high, the solvent tends to evaporate.
In order to increase the extraction efficiency, stirring is preferably performed in the extraction step. The stirring time is preferably performed until distribution equilibrium is reached, but may be interrupted halfway. Usually, it is appropriately selected from the range of 10 minutes to 5 hours.
Among the components in the catalyst solution, the saccharide is distributed to the polar solvent phase. At this time, the monosaccharides and disaccharides in the polar solvent are controlled if necessary, by discarding a part or most of them and circulating them in the process. be able to.

(3) Catalyst Circulation Step As shown in FIG. 1, in the method of the present invention, the catalyst or unreacted dicarboxylic acid obtained in the extraction step and a catalyst solution containing monosaccharides and / or disaccharides are circulated in the reaction step. It is preferable.
As the components to be circulated, a solvent and other components may be included in addition to the above active components as long as they do not adversely affect the reaction process, but it is preferable to circulate components having a higher boiling point than the target product.

For example, in FIG. 1, the high-boiling components containing unreacted dicarboxylic acids separated from the lactone and other light-boiling compounds in the first distillation column are circulated to the reaction step through the extraction step. .
In the present invention, by using the above-described method, sugars mixed in the reaction raw material are circulated as a high boiling point component accompanying the catalyst and accumulated in the process. For this reason, in order to make the total concentration of monosaccharides and disaccharides in the reaction step within the scope of the present invention, for example, it is preferable to discharge (purge) a part of the high-boiling components containing the saccharides out of the system. .

The method for purging the high boiling point component out of the system is not particularly limited. For example, even if the catalyst solution in which the high boiling point component is accumulated is purged from the bottom of the distillation column, The part may be purged out of the system.
For example, by extracting the catalyst into a non-polar solvent layer with the extractor shown in FIG. 1 and purging the polar solvent layer containing saccharide separated therefrom, it is possible to purge high boiling components at the same time, which is economically advantageous.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited by a following example, unless the summary is exceeded.
1. Raw material Succinic acid and glucose: Special grade of reagent (Wako Pure Chemical Industries, Ltd.)

2. Analysis [Gas chromatography analysis]
GBL was analyzed using a DB-1 column (nonpolar) manufactured by Agilent with a gas chromatography analyzer (GC-17A model manufactured by Shimadzu Corporation).
[Liquid chromatography analysis]
Sugar analysis was performed using a MCI GEL CK08EH column manufactured by Mitsubishi Chemical Corporation with a high performance liquid chromatography analyzer (LC-10Ai manufactured by Shimadzu Corporation). The eluent was a 0.02% formic acid aqueous solution.
[Inductively coupled plasma optical emission spectrometry (ICP-OES)]
Ru analysis was performed by an organic solvent direct introduction method using an ICP emission spectrometer (iCAP6500Duo, manufactured by Thermo Scientific, Peltier cooled organic solvent introduction system).

3. Examples and Comparative Examples <Example 1>
In a 100 ml autoclave (material: SUS316), 5.9 g (11.8 mass%) of succinic acid and a ruthenium complex having trioctylphosphine as a ligand dissolved in triglyme 5.0 g (Ru: 400 mass ppm) Then, 0.001 g of glucose (glucose: 20 mass ppm) and 33.1 g of triglyme as a solvent were charged, and a magnetic rotary stirrer was put in the autoclave, and then the system was sufficiently replaced with hydrogen. The temperature was raised while stirring using a magnetic stirrer, and hydrogen was injected so that the internal pressure became 0.9 MPa · G (G represents the gauge pressure) when the internal temperature of the autoclave reached 205 ° C. This time was set as the start of the reaction, and the hydrogenation reaction was continued for 2 hours. After completion of the reaction, the resulting reaction solution was collected and analyzed by gas chromatography. As a result, the yield of γ-butyrolactone was 27.3%. The reaction results are shown in Table 1.
<Examples 2 to 4>
A hydrogenation reaction was carried out in the same manner as in Example 1 except that the glucose concentration was 50, 500, and 1000 mass ppm. After completion of the reaction, the reaction solution was collected and analyzed by gas chromatography. The reaction results are shown in Table 1.

<Comparative Example 1>
A hydrogenation reaction was carried out in the same manner as in Example 1 except that the glucose concentration was 3000 ppm by mass. After completion of the reaction, the reaction solution was collected and analyzed by gas chromatography. The reaction results are shown in Table 1.

<Comparative Example 2>
The hydrogenation reaction was carried out in the same manner as in Example 1 except that glucose was not added to the hydrogenation reaction raw material (the glucose concentration in the hydrogenation reaction raw material was less than 20 ppm by mass). After completion of the reaction, the reaction solution was collected and analyzed by gas chromatography. The reaction results are shown in Table 1.

4). Evaluation of results In Examples 1 to 4, the GBL yield was stably increased by keeping the concentration of glucose (monosaccharide) during the hydrogenation reaction within the range specified in the present application.
In Comparative Examples 1 and 2, this concentration exceeds the range of the present application, and the yield is significantly reduced. From the above results, the effects of the present invention are clear.

Claims (7)

In the method for producing a corresponding lactone by hydrogenation reaction of a dicarboxylic acid and / or a derivative thereof (hereinafter collectively referred to as “dicarboxylic acids”) obtained from a raw material derived from biomass resources, the reaction during the hydrogenation reaction The total concentration of monosaccharides and disaccharides in the mixture is 2
A method for producing a lactone, wherein the content is 0 mass ppm or more and 1000 mass ppm or less . The method for producing a lactone according to claim 1 , wherein the hydrogenation reaction is performed using a heterogeneous catalyst and / or a homogeneous catalyst containing a metal belonging to Groups 8 to 11 of the periodic table. The method for producing a lactone according to claim 2 , wherein the metal belonging to Groups 8 to 11 of the periodic table in the catalyst is ruthenium and / or copper. The method for producing a lactone according to claim 3 , wherein the catalyst is a ruthenium complex having an organophosphorus compound as a ligand. The method for producing a lactone according to any one of claims 1 to 4 , wherein the dicarboxylic acid is succinic acid and / or a derivative thereof. A method for producing a corresponding lactone obtained from a raw material derived from biomass resources by hydrogenation reaction of dicarboxylic acids has a reaction step, a purification step, and a catalyst circulation step from the purification step to the reaction step. The total concentration of monosaccharides and disaccharides in the reaction mixture is 20 mass p.
A method for producing a lactone, wherein the range is from pm to 1000 ppm by mass. In the catalyst circulation process, according to claim 6, characterized in that to adjust the total amount of monosaccharides and disaccharides sequentially performs extraction processing of the solvent was distilled off process and catalyst, and recycled to the reaction step in the extraction process A process for producing the lactone according to 1.

Images