GB2169614A - Producing alpha-olefins and their conversion into lubricants - Google Patents

Abstract

C5-20 alpha-olefins are made by contacting a mixture of hydrogen and carbon monoxides, e.g., syngas, at 200-260 DEG C with a catalyst comprising iron to produce a mixture of alpha-olefins. In a subsequent stage, the mixture of olefins may be polymerized in the presence of an acidic or acid-acting catalyst or a Ziegler-Natta polymerization catalyst to produce synthetic lubricants, e.g. having an average molecular weight of 300 to 10,000.

Description

SPECIFICATION Process for producing alpha-olefins and for their conversion into lubricants This invention relates to the production of alpha-olefins and more particularly to the production of CH to C20 alpha-olefins with improved yield and selectivity, by a Fischer-Tropsch process. This invention relates also to the production of hydrocarbon fluids having superior lubricating properties from such alpha-olefins.

Processes for the conversion of coal and hydrocarbons, such as natural gas, to a gaseous mixture consisting essentially of hydrogen, carbon monoxide and/or carbon dioxide are well-known. One of the oldest, and probably best known, processes of this kind is the so-called Fisher-Tropsch synthesis process wherein coal is first burned in the presence of steam or oxygen to produce predominantly carbon-monoxide, some carbon dioxide and hydrogen, and then the thus-obtained synthesis gas is converted in the presence of nickel, iron or cobalt catalysts to a mixture of hydrocarbons, such as lower olefins of 2 to 6 carbons, alcohols, e.g., methanol, aldehydes, ketones and fatty acids.

For example, Pier et al, U.S. Patent 2,318,626, disclose the production of hydrocarbons rich in unsaturates by reacting the mixture of carbon monoxide and hydrogen at a temperature of about 162" to about 350"C in the presence of catalysts, such as cobalt or nickel, mixtures of iron and copper, sintered metals of the iron group, metals of the iron group with manganese and copper or with aluminum.

Fischer et al, U.S. Patent 1,746,464, disclose a process producing paraffin hydrocarbons by contacting oxides of carbon mixed with hydrogen or hydrogen-containing gases with a catalyst, such as a mixture of zinc oxide and iron, cobalt, iron and copper, and potassium carbonate-modified metal catalysts, such as potassium carbonate-modified iron. The use of lower temperatures, such as 250"C, increases the yield of higher molecular weight paraffins.

Brennan et al, U.S. Patent 4,269,783, disclose a process of converting syngas (i.e., a mixture of carbon monoxide and hydrogen) to high octane naphtha containing olefins having predominantly internal double bonds in the presence of a catalyst comprising a Fischer-Tropsch catalytic component and an acidic cracking catalyst.

Kortbeek et al, U.S. Patent 4,410,637, disclose a process for the preparation of hydrocarbon mixture of acyclic, gasoline range hydrocarbons by contacting a mixture of hydrogen and carbon monoxide with a Fischer-Tropsch catalyst containing a crystalline silicate, e.g., magadiite.

Chang et al, U.S. Patent 4,418,155, disclose a process for converting syngas to hydrocarbons enriched in linear alpha-olefins, comprising contacting the syngas with a catalyst comprising a ZSM-5 type zeolite having deposited thereon a carbon oxide reducing component, such as Fischer-Tropsch catalyst, e.g., iron, cobalt and ruthenium. The reaction is carried out at a temperature of about 260 to about 345"C, preferably at about 287 to about 316"C.

Bussemeir et al, 'Lower Olefins Via Fischer-Tropsch', Hydrocarbon Processing, November 1976, pages 105-112, teach that the Synthol process, operating at temperatures of 320 to 340"C, produces a higher proportion of lower olefins than the Arge process, operating at temperatures of 220 to about 240"C.

It is also known that synthetic lubricants and viscosity index improvers for lubricants can be produced by polymerizing olefins or a mixture of olefins and other hydrocarbons. For example, Wietzel et al, U.S.

Patent 1,798,288, disclose a two-step process for making lubricants comprising, converting a mixture of hydrogen and carbon oxides to low boiling point range hydrocarbons in the presence of a catalyst containing a metal from Group VIII of the Periodic Table at a temperature of 270"C to 350"C, and then converting the low boiling point hydrocarbons to lubricating oils in the presence of a metal-containing catalyst, e.g., aluminum chloride. The characteristics of the lubricating oils, e.g., viscosity index or molecular weight, are not disclosed.

Anderson, U.S. Patent 2,620,365, also discloses a two-stage process for synthesizing lubricants, comprising isomerizing C5-C25 alpha-olefins in the presence of a solid alumina type catalyst, and then polymerizing the isomerized product in the presence of a Friedel-Crafts type catalyst, e.g., aluminum chloride.

Smith et al, U.S. Patent 3,682,823, Shubkin, U.S. Patent 3,780,128, Cupples et al, U.S. Patent 4,282,392, Dorden et al, U.S. Patent 4,400,565 and Larkin et al, U.S. Patent 4,417,082, disclose the preparation of synthetic lubricants by polymerization and oligomerization of alpha-olefins.

According to the invention, higher alpha-olefins having 5 to 20 carbon atoms (C5-C20 alpha-olefins), are produced in a process comprising contacting, at a temperature of about 200 to about 260"C, a reactants stream comprised of carbon monoxide and hydrogen with a catalyst which is comprised of iron. The product of the reaction comprises at least 20% by weight of C0C20 alpha-olefins. The catalyst may also contain a promoter which is at least one element or a compound of an element of the group consisting of: alkali metals, alkaline earth metals, metals of Group VIA of The Periodic Chart of the Elements, titanium, zirconium, aluminum, arsenic, vanadium, manganese, copper, silver, zinc, cadmium, bismuth, lead, tin, cerium, thorium and uranium.Maintaining the temperature in the reaction zone within the aforementioned range of 200 to 260"C assures high selectivity and yield of the reaction to C5-C20 alpha-olefins.

According to a further aspect of the invention, hydrocarbon fluids having superior lubricating properties are produced in a three step process, the production of C, to C20 alpha-olefins forming the first of those steps. In the second step of the process, at least one fraction comprising hydrocarbons having a boiling point of between about 75"F and about 600OF is separated from the product of the first step. Subsequently, in the third step or stage of the process, that fraction is polymerized in the presence of an acidic or acid-acting polymerization catalyst. The resulting liquid hydrocarbon fluids have a viscosity index of at least about 90, an average carbon number of at least about 24, and average molecular weight of about 300 to about 10,000.

The reactants stream used in the first step of the invention as the feed comprises a mixture of hydrogen and carbon monoxide. In a typical operation, reactor feed hydrogen plus carbon monoxide partial pressure is from 2 to 50 atmospheres, preferably 6 to 35 atmospheres. Additionally, carbon dioxide may be present in the feed in amounts of about 0.1 volume percent to about 80 volume percent, along with methane, nitrogen, oxygen, light paraffins and olefins (C2 to about C10), and other products of the Fischer Tropsch reaction recycled to conserve unreacted syngas or cool the reactor. The reactant stream introduced into the reactor zone of the first step has the molar ratio of hydrogen to carbon monoxide of about 0.3 to about 4, preferably about 0.5 to about 2, and most preferably about 0.50 to about 1.Such hydrogen/carbon monoxide mixtures can be suitably prepared by steam gasification or partial combustion of a carbon-containing material, as is known to those skilled in the art. Examples of suitable carbon-containing materials which can be used in such a gasification or combustion process are coal, anthracite, coke, crude mineral oil and fractions thereof, tars and oils extracted from tar sands and bituminous shale. The steam gasification or partial combustion is carried out in a conventional manner, preferably at the temperature of about 900" to about 1600"C and the pressure of about 10 to about 100 atmospheres.

The first step of the process of this invention is carried out in a manner conventional to that of other Fischer-Tropsch reactions of prior art. Thus, the first step of the process can be carried out in a fixed bed or a slurry operation process, both of which are described, e.g., in H. Koelbel and M. Ralek CATALYSIS REVIEWS-SCIENCE & ENGR. 21(2), 225-274 (1980) and M.E. Dry, CATALYSIS SCIENCE AND TECHNOL OGY (Anderson & Boudart ed) Chapter 4, Vol. 1, 1981, pp. 159-255, the contents of both of which are incorporated herein by reference.

The catalyst compositions used in the first step of the present invention are those known in the art as Fischer-Tropsch catalysts. Such catalysts comprise iron, iron compounds or a mixture thereof, optionally with one or more promoters to increase the activity, stability and/or selectivity of the reaction.

Suitable promoters for the catalyst of the first step are at least one element or a compound of an element selected from the following group: alkali metals, alkaline earth metals, metals of group VIA of the Periodic Chart of the Elements, titanium, zirconium, aluminum, silicon, arsenic, vanadium, manganese, cooper, silver, zinc, cadmium, bismuth, lead, tin, cerium, thorium and uranium. The term 'Periodic Chart of the Elements', as used herein, designates a table of The Periodic Chart of the Elements, published by the Fisher Scientific Company, Catalogue No. 6-702-10, 1978. The preferred promoters are sodium, potassium, rubidium, cesium or copper, preferably a combination of potassium and copper or compounds thereof. The amount of the promoter is about 0.05 to about 100.0 grams, preferably about 0.2 to about 20.0 grams, per 100 grams of iron.The above amounts define the content of each component of the promoter in the catalyst. Therefore, for example, if the catalyst is promoted with silica and manganese, it may contain about 0.05 to about 100 grams of silica and about 0.05 to about 100 grams of manganese per 100 grams of iron. In the most preferred embodiment, the catalyst comprises iron (Fe), promoted with potassium carbonate (K2CO3) and copper (Cu), in the following proportions: about 0.1 to about 1.0 gram of Cu per 100 grams of Fe, and about 0.1 to about 1.0 gram of K2CO3 per 100 grams of iron.

The catalyst composition may be unsupported or supported on alumina, silica, titania, silica-alumina, natural or synthetic zeolites or molecular sieves, and such supports may be modified with alkali metals, especially Na, K or Cs.

The temperature of the reaction is maintained at about 200 to about 350"C, preferably about 200 to about 260 , more preferably about 210 C to about 250"C, and most preferably about 220 to about 245"C.

Maintaining the reaction temperature within these temperature ranges improves the yield and selectivity of the reaction to higher alpha-olefins containing 5 to 20 carbon atoms.

The molar ratio of hydrogen to carbon monoxide within the reaction zone of the first step is also important for increasing the yield and selectivity of the reaction to higher alpha-olefins. Thus, the molar ratio of hydrogen to carbon monoxide in the reaction zone must be maintained between about 0.3 and about 4, preferably about 0.5 and about 2, and most preferably about 0.5 and about 1. For example, at the temperature of about 220"C and the H2/CO molar ratio of 0.65 in the feed and 0.68 in the effluent, the effluent of the reaction of the first step contains about 20% by weight of C8-C20 linear alpha-olefins, on the basis of total hydrocarbons in the reaction effluent. The amount of alpha-olefins decreases progressively with increasing temperature at substantially constant H2/CO molar ratio.

Alpha-olefins produced in the first step of the process of the present invention can be branched or unbranched alpha-olefins and they may contain more than one double bond. Thus, some of the alphaolefins produced in the first step are 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1nonene, 1-undecene 3- or 4-methyl-pentene-1, 3-, 4-or 5-methyl-hexene-1, 3-, 4- or 5-methyl-octene-1, 2-, 4-dimethyl-decene-1 and 3-ethyl-nonene-1.

The first step of the present invention is suitably carried out by conducting the feed in an upward or downward direction through a vertically-mounted reactor containing a fixed bed of the catalyst. This step can also be carried out by using a suspension of the catalyst in a hydrocarbon oil. The process is con ducted at a pressure of about 50 to about 1000 psig, preferably at about 100 to about 400 psig. After the reaction effluent is recovered from the first step of the reactor, the desired stream rich in alpha-olefins is recovered therefrom by any conventional technique, such as fractionation, and the remainder of the stream is recycled into the reaction zone for additional conversion to alpha-olefins.

The hydrocarbon effluent product of the first step comprises at least 20%, preferably about 20% to about 40%, and most preferably about 20% to about 30% by weight (% wt) of C5-C20, alpha olefins. The hydrocarbon effluent product comprises at least 15%, preferably about 15% to about 35% and most preferably about 15% to about 25% by weight of C8-C20 alpha-olefins. The hydrocarbon effluent product also comprises at least 8%, preferably about 8% to about 25%, and most preferably about 8% to about 16% by weight of C,2-C20 alpha-olefins.

After the reaction effluent is recovered from the first step reactor, at least one hydrocarbon product having a boiling point of between about 75"F and about 600OF, preferably about 220OF to about 440OF, is separated thereform, in the second step of the process, by any conventional technique, such as fractionation, and the remainder of the stream is treated to produce useful hydrocarbon products, i.e., fuels, gasoline or diesel fuel. The hydrocarbon product, separated from the effluent of the first step, comprises at least 50%, preferably at least 60%, and most preferably about 65% to about 95% by weight of alphaolefins based on total olefins in the hydrocarbon product.

The hydrocarbon product obtained from the second step is polymerized, in the third step of the process, in the presence of an acidic or acid-acting catalyst, or at least one Ziegler-Natta polymerization catalyst. Suitable acidic or acid-acting catalysts used in the third step or stage of the process of the invention are usually referred to in the art as acidic catalysts (see e.g., Kirk-Othmer ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY, Third Edition, Volume 5, pages 33-36 (1979), the contents of which are incorporated herein by reference.Such catalysts are Lewis Acid catalysts, acid resins, solid phosphoric acid catalysts, clays, acidic amorphous porous silicates, acidic crystalline metallo-silicates, such as suitable zeolites, and other acidic oxides, or a catalyst composition comprising a reaction product of a particular type of crystalline aluminosilicate zeolite and the particular type of an organometallic compound.

Suitable Lewis Acid catalysts are metal halide catalysts, also known in the art as Friedel-Crafts catalysts. Such catalysts have an electron-deficient central metal atom capable of accepting electrons from basic reagents. Examples of Lewis Acid catalysts are aluminum chloride (AICI2), aluminum bromide (AlBr81, boron trifluoride (BF2), zirconium tetrachloride (ZrCI4), antimony pentafluoride (SbF,), antimony pentachloride (SbCI5), antimony trichloride (SbCI3), zinc chloride (ZnCI2), boron chloride (BCI2), beryllium chloride (BeCI2), cadmium chloride (CdCI2), boron bromide (BBr2), gallium chloride (GaCI2), gallium bromide (GaBr3), titanium tetrachloride (TiCi4), tin chloride (SnCI4), tin bromide (SnBr4), bismuth chloride (BiCI2), iron chloride (FeCI3) and uranium chloride (UCI4) (see Kirk-Othmer 'Encyclopedia of Chemical Technology', Third Edition, Vol. 11, John Wiley and Sons, New York, 1980, pages 269-297, the entire contents of which are incorporated herein by reference).

If a Lewis Acid catalyst is used, it may be promoted with about 0.1 to about 10% wt. of a known promoter, such as methanol, 1-butanol, isopropanol, amyl alcohol, tertiary butyl alcohol, water, hydrogen chloride, hydrogen bromide, ethyl chloride, tertiary butyl chloride and tertiary butyl bromide. The Lewis Acid-catalyzed reaction is conducted in the presence of a solvent, such as paraffins, e.g., Fisher-Tropsch paraffins, hexane, pentane, heptane, octane, petroleum ether, naphtha and other known solvents, e.g., chloroform and ethyl chloride. The reaction of this stage is conducted at a temperature of about 0 C to about 120"C, preferably about 25"C to about 60"C, and pressure of about 1 to about 15 atmospheres for 0.5 hours to 70 hours.The reaction is terminated by any conventional means, such as quenching, e.g., with ammonia, water or aqueous-based fluids, such as ammonium hydroxide. The reaction product is separated from the reaction medium by any suitable means, e.g., filtration. The filtrate is washed with a suitable solvent, e.g., water, to remove unreacted reactants, and dried. The volatiles are removed by any suitable means, e.g., evaporation, and a hydrocarbon fluid, having a desirable boiling point range (e.g., at least 600OF for synthetic lubricants) is separated from the product mixture of any conventional means, e.g., fractional or vacuum distillation.

Any Ziegler-Natta olefin polymerization catalyst may be used in this step of the reaction. Suitable Ziegler-Natta catalysts are those, for example, disclosed by Stevens et al, U.S. Patent 3,787,384, Strobel et al, U.S. Patent 4,148,754, Graff, U.S. Patent 4,173,547, Karol et al, 4,302,566, and Nowlin et al, U.S. Patent 4,481,301, the entire contents of all of which are incorporated herein by reference. The most preferred Ziegler-Natta polymerization catalyst is that of Nowlin et al, U.S. Patent 4,481,301, referred to herein as 'a highly active Ziegler-Natta catalyst of Nowlin et al'.

If a Ziegler-Natta catalyst is used in this step of the process, the reaction is conducted under the operating conditions suitable for a given Ziegler-Natta catalyst in suspension, in solution or in the gas phase process, except fluidized bed process, as disclosed in the aforementioned patents. It will be apparent to those skilled in the art that gas phase fluidized bed processes disclosed in these patents are not suitable for this step of the process of the present invention.

The aforementioned Ziegler-Natta catalysts used in the third step of the invention may be used in the as-synthesized form (disclosed in the aforementioned patents), or they may be combined with a suitable support prior to the introduction thereof into the third step of the process of this invention. Suitable supports for such Ziegler-Natta catalysts are amorphous materials, such as silica-alumina, silica, alumina, and zeolites, such as mordenite, faujasite-type materials, e.g., ultrastable Y zeolite and rare earth-exchanged X and Y zeolites (disclosed e.g., by Lindsley, U.S. Patent 4,125,591), zeolite Beta (see U.S. Patent 3,308,069) and zeolites having a Constraint Index of about 1 to 12, such as ZSM-5 (see U.S. Patent 3,702,886), ZSM-5/1 1 intermediate (see U.S. Patent 4,229,424), ZSM-11 (see U.S. Patent 3,709,979), ZSM12 (see U.S.Patent 3,832,449), ZSM-23 (see U.S. Patent 4,076,842), ZSM-35 (see U.S. Patent 4,016,245), ZSM-38 (see U.S. Patent 4,046,859), and ZSM-48 (see U.S. Patent 4,375,573). The entire contents of each of the above patents are incorporated herein by reference.

Acid resin catalysts useful in the third step of the invention comprise a polymeric resin matrix having at least one acidic functional group, such as a sulfonic, phosphonic, phenyl sulfonic, phenylphosphonic or phenylsulfonic groups. The polymeric resin matrix is any suitable resin known to those skilled in the art, as discussed below. Preferably, the polymeric resin matrix is porous, either initially or it becomes porous during the course of the third step of the process of this invention. Preferred resin materials are phenolic resin, polystyrene resin, copolymers of styrene with polyfunctional polymerizable monomers such as styrene-divinyl aryls, e.g., divinyl benzene, or acrylates, such as polyacrylic or polymethacrylic acid resins, and halogenated derivatives of the aforementioned resin materials.Most preferably, the acid resin catalysts are cation exchange resins, such as Dowex 50 (Dow Chemical Company) or Amberlyst 15 (Rohm and Haas Company). The relative proportions of the acidic functional groups in the resin are about 1 to about 10 millimole equivalents (Meq) of acidic functional groups per gram of matrix preferably, about 1 to about 5 Meq per gram of matrix.

Solid phosphoric acid catalysts may also be used herein. Such catalysts comprise phosphoric acid supported on a suitable porous matrix, such as clays, silica, silicate, carbon and kieselguhr. Relative proportions of the phosphoric acid to the porous matrix can vary widely, as will be obvious to those skilled in the art, and they are not critical. For example, a suitable catalyst of this type comprises 60 wt % of amorphous pentoxide supported on 40 wt % of kieselguhr.

Acidic clay materials useful in this step of the invention are known to those skilled in the art and they are exemplified by kaolinite treated with 5 to 50 Meq per 100 gr of sulfuric acid.

Acidic crystalline metallo-silicates useful in the third step of the process have the formula: Mz,,O Me2O2 y SiO2 z H2O, wherein M is a cation; n is its valency; Me is a tri-valent ion, such as aluminum, iron, or gallium; y is moles of silica; and z is moles of water. Preferred acidic crystalline metallo-silicates are aluminosilicates.

Examples of suitable aluminosilicates are large pore zeolites, e.g., faujasite and mordenite, and zeolites having the Constraint Index of 1-12, a silica to alumina molar ratio of at least about 12 and a dried crystal density of at least 1.6 grams/cm3, e.g., ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 or ZSM-48, all of which are described in the patents and publications cited above.

Yet another catalyst useful in the third step of the invention comprises a reaction product of at least one crystalline aluminosilicate zeolite with at least one organometallic compound. The crystalline alumi nosilicate zeolites useful in the preparation of such a catalyst have a silica to alumina molar ratio of at least about 12 and a Constraint Index of about 1 to 12. The organometallic compounds employed are tri or tetra-valent titanium or chromium compounds having alkyl moieties and optional halo moieties, wherein the 'alkyl' moieties thereof include both straight and branched chain alkyl groups, cycloalkyl groups and aralkyl groups.

The silica to alumina mole ratio of the zeolites may be determined by conventional analysis. This ratio is meant to represent, as closely as possible, the ratio in the rigid anionic framework of the zeolite crystal and to exclude aluminum in the binder or in cationic or other form within the channels. Although zeolites with a silica to alumina mole ratio of at least 12 are useful, it is preferred in some instances to use zeo lites having substantially higher silica/alumina ratios, e.g., 1600 and above. In addition, zeolites as other wise characterized herein but which are substantially free of aluminum, that is zeolites having silica to alumina mole ratios of up to infinity, are found to be useful and even preferable in some instances. Such 'high silica' or 'highly siliceous' zeolites are intended to be included within this description.Also to be included within this definition are substantially pure silica analogs of the useful zeolites described herein, that is those zeolites having no measurable amount of aluminum (silica to alumina mole ratio of infinity) but which otherwise embody the zeolite characteristics disclosed herein.

Members of this particular class of zeolites, after activation, acquire an intracrystalline sorption capacity for normal hexane which is greater than that for water, i.e., they exhibit 'hydrophobic' properties. This hydrophobic character can be used to advantage in some applications.

The zeolites useful in preparing the catalyst by reacting the zeolite with the organometallic compound have an effective pore size such as to freely sorb normal hexane. In addition, their structure must provide constrained access to larger molecules. It is sometimes possible to judge from a known crystal structure whether such constrained access exists. For example, if the only pore windows in a crystal are formed by 8-membered rings of silicon and aluminum atoms, then access by molecules of larger cross-section than normal hexane is excluded and the zeolite is not of the desired type. Windows of 10-membered rings are preferred, although in some instances excessive puckering of the rings or pore blockage may render these zeolites ineffective.

Although 12-membered rings in theory would not offer sufficient constraint to produce advantageous conversions, it is noted that the puckered 12-ring structure of TMA offretite does show some constrained access. Other 12-ring structures may exist which may be operative for other reasons and, therefore, it is not the present intention to entirely judge the usefulness of the particular zeolite solely from theoretical structural considerations.

Rather than attempt to judge from crystal structure whether or not a zeolite possesses the necessary constrained access to molecules of larger cross-section than normal paraffins, a simple determination of the 'Constraint Index' as herein defined may be made by passing continuously a mixture of an equal weight of normal hexane and 3-methylpentane over a sample of zeolite at atmospheric pressure according to the procedure disclosed in prior art (e.g., see Haag et al, U.S. Patent 4,374,296 and Daviduk et al, U.S. Patent 4,379,123, the disclosures of both of which are incorporated herein by reference).

The Constraint Index is an important and even critical definition of those zeolites which are useful herein. The very nature of this parameter and the recited technique by which it is determined, however, admit of the possibility that a given zeolite can be tested under somewhat different conditions and thereby exhibit different Constraint Indices. Constraint Index seems to vary somewhat with severity of operation (conversion) and the presence or absence of binders. Likewise, other variables such as crystal size of the zeolite, the presence of occluded contaminants, etc., may affect the Constraint Index. Therefore, it will be appreciated that it may be possible to so select test conditions as to establish more than one value in the range of 1 to 12 for the Constraint Index of a particular zeolite.Such a zeolite exhibits the constrained access as herein defined and is to be regarded as having a Constraint Index in the range of 1 to 12. Also contemplated herein as having a Constraint Index in the range of 1 to 12 and therefore within the scope of the defined class of highly siliceous zeolites are those zeolites which, when tested under two or more sets of conditions within the above-specified ranges of temperature and conversion, produce a value of the Constraint Index slightly less than 1, e.g. 0.9, or somewhat greater than 12, e.g. 14 or 15, with at least one other value within the range of 1 to 12. Thus, it should be understood that the Constraint Index value as used herein is an inclusive rather than an exclusive value.That is, a crystalline zeolite when identified by any combination of conditions within the testing definition set forth herein as having a Constraint Index in the range of 1 to 12 is intended to be included in the instant novel zeolite definition whether or not the same identical zeolite, when tested under other of the defined conditions, may give a Constraint Index value outside of the range of 1 to 12.

The particular class of zeolites useful in preparing the catalyst by reacting a zeolite with an organometallic compound is exemplified by ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other similar materials. These zeolites are disclosed in the patents identified above.

In all of the foregoing zeolites, the original cations can be subsequently replaced, at least in part, by calcination and/or ion exchange with another cation. Thus, the original cations can be exchanged into a hydrogen or hydrogen ion precursor form or a form in which the original cations have been replaced by a metal of, for example, Groups II through VIII of the Periodic Table. Thus, it is contemplated to exchange the original cations with ammonium ions or with hydronium ions. Catalytically active forms of these zeolites would include, in particular, hydrogen, rare earth metals, calcium, nickel, palladium and other metals of Groups II and VIII of the Periodic Chart. It is generally the hydrogen form of such zeolites which can be reacted with the organometallic compounds to form the polymerization catalysts useful in the third step of the present invention.

It is to be understood that by incorporating by reference the foregoing patents to describe examples of specific members of the specified zeolite class with greater particularity, it is intended that identification of the therein disclosed crystalline zeolites be resolved on the basis of their respective X-ray diffraction patterns. As discussed above, the present invention contemplates utilization of such catalysts wherein the mole ratio of silica to alumina is essentially unbounded.The incorporation of the above-identified patents should therefore not be construed as limiting the disclosed crystalline zeolites to those having the specific silica-alumina mole ratios discussed therein, it now being known that such zeolites may be substantially aluminumfree and yet, having the same crystal structure as the disclosed materials, may be useful or even preferred in some applications. It is the crystal structure, as identified by the X-ray diffraction 'fingerprint', which establishes the identity of the specific crystalline zeolite material.

The specific zeolites, when prepared in the presence of organic cations, are substantially catalytically inactive, possibly because the intra-crystalline free space is occupied by organic cations from the forming solution. They may be activated by heating in an inert atmosphere at 540"C for one hour, for example, followed by base exchange with ammonium salts followed by calcination at 5400C in air. The presence of organic cations in the forming solution may not be absolutely essential to the formation of this type zeolite; however, the presence of these cations does appear to favor the formation of this special class of zeolites. More generally, it is desirable to activate this type of zeolite by base exchange with ammonium salts followed by calcination in air at about 540"C for from about 15 minutes to about 24 hours.

Natural zeolites may sometimes be converted to zeolite structures of the class herein identified by various activation procedures and other treatments, such as base exchange, steaming, alumina extraction and calcination, alone or in combinations. Natural minerals which may be so treated include ferrierite, brewsterite, stilbite, dachiardite, epistilbite, heulandite, and clinoptilolite.

The preferred crystalline zeolites reacted with the organometallic compound(s) to form one of the catalyst compositions used in the third stage of the present invention include ZSM-5, ZSM-11, ZSM-12, ZSM23, ZSM-35, ZSM-38 and ZSM-48, with ZSM-5 being particularly preferred.

Crystalline zeolites used for that purpose generally have a crystal dimension of from about 0.01 to 100 microns, more preferably from about 0.02 to 10 microns.

Preferably, such zeolites are selected which have a crystal framework density, in the dry hydrogen form, of not less than about 1.6 grams per cubic centimeter. It has been found that zeolites which satisfy all three of the discussed criteria are most desired for several reasons. Therefore, the preferred zeolites useful in preparing the zeolite/organometallic compound(s) catalyst of the third step of the invention are those having a Constraint Index as defined above of about 1 to about 12, a silica to alumina mole ratio of at least about 12 and a dried crystal density of not less than about 1.6 grams per cubic centimeter. The dry density for known structures may be calculated from the number of silicon plus aluminum atoms per 1000 cubic Angstroms, as given, e.g., on page 19 of the article ZEOLITE STRUCTURE by W. M. Meier.

This paper, the entire contents of which are incorporated herein by reference, is included in PROCEED INGS OF THE CONFERENCE ON MOLECULAR SIEVES, (London, April 1967) published by the Society of Chemical Industry, London, 1968.

When the crystal structure is unknown, the crystal framwork density may be determined by classical pyknometer techniques. For example, it may be determined by immersing the dry hydrogen form of the zeolite in an organic solvent which is not sorbed by the crystal. Or, the crystal density may be determined by mercury porosimetry, since mercury will fill the interstices between crystals but will not penetrate the intracrystalline free space.

When synthesized in the alkali metal form, the zeolite is conveniently converted to the hydrogen form, generally by intermediate formation of the ammonium form as a result of ammonium ion exchange and calcination of the ammonium form to yield the hydrogen form. In addition to the hydrogen form, other forms of the zeolite wherein the original alkali metal has been reduced to less than about 1.5 percent by weight may be used as precursors to the alkaline earth metal-modified zeolites of the present invention.

Thus, the original alkali metal of the zeolite may be replaced by ion exchange with other suitable metal cations of Groups I through VIII of the Periodic Table, including, by way of example, nickel, copper, zinc, palladium, calcium or rare earth metals. As indicated, it is generally the hydrogen form of the zeolite component which is reacted with the organometallic compound(s) to produce the catalyst used in the third stage of the present invention.

In practicing the third stage of the process of the present invention with the zeolite/organometallic compound(s) catalyst, it may be useful to incorporate the above-described crystalline zeolites, prior to their reaction with the organic compound(s), with a matrix comprising another material resistant to the temperature and other conditions employed in the process. Such matrix material is useful as a binder and imparts greater resistance to the catalyst for the temperature, pressure and reactant feed stream velocity conditions encountered in, for example, polymerization processes.

Useful matrix materials include both synthetic and naturally occurring substances, as well as inorganic materials, such as clay, silica and/or metal oxides. The latter may be either naturally occurring or in the form of gelatinous precipitates or gels including mixtures of silica and metal oxides. Naturally occurring clays which can be composited with the zeolite include those of the montmorillonite and kaolin families, which families include the sub-bentonites and the kaolins commonly known as Dixie, McNamee-Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification.

In addition to the foregoing materials, the zeolites may be composited with a porous matrix material, such as alumina, silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, and silica-titania, as well as ternary compositions, such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesia-zirconia. The matrix may be in the form of a cogel. The relative proportions of zeolite component and inorganic oxide gel matrix, on an anhydrous basis, may vary widely with the zeolite content ranging from between about 1 to about 99 percent by weight and more usually in the range of about 5 to about 80 percent by weight of the dry composite.

To form the zeolite/organometallic compound catalyst of the present invention, the crystalline zeolite material is reacted with a particular type of organometallic compound. Organometallic compounds useful in forming the catalysts include trivalent and tetravalent organotitanium and organochromium compounds having alkyl moieties and, optionally, halo moieties. In this context, the term 'alkyl' includes both straight and branched chain alkyl, cycloalkyl and alkaryl groups, such as benzyl. According, the organometallic compounds used to form the catalysts correspond to the general formula: M Y,X,., wherein Mis a metal selected from a group consisting of titanium and chromium; Y is alkyl; X is halogen (e.g., CI or Br); n is 1-4; and m is greater than or equal to n and it is 3 or 4.

Preferably Y is of the formula:

where R1 and R2 are each selected from H and methyl; and R2 is H, alkyl, cyclohexyl, alkylcyclohexyl, cyclohexylalkyl, phenyl, alkylphenyl, benzyl, or dimethylbenzyl.

Examples of organotitanium or organochromium compounds encompassed by such a formula include compounds of the formula CrY4, CrY3, CrY3X, CrY2X, CrY2X2,CrYX2, CrYX2, TiY4, Tit2, TiY3X, TiY2X, TiY2X2, TiYX2 and TiYX3, wherein X can be Cl or Br and Y can be alkyls, e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, isohexyl, neohexyl, 2-ethylbutyl, octyl, 2-ethylhexyl, 2,2-diethylbutyl, 2-isopropyl-3-methylbutyl, etc., cyclohexylalkyls, such as - (CH2), -C6H11 where n is 1 to 4, for example, cyclohexylmethyl, 2-cyclohexylethyl, 3-cyclohexylpropyl, 4-cyclohexylbutyl, and the corresponding alkyl-substituted cyclohexyl radicals, for example, (4-methylcyclohexyl)methyl, neophyl, i.e., beta, beta-dimethyl-phenethyl, benzyl, ethylbenzyl and p-isopropylbenzyl. Preferred examples of Y include C1 5 alkyl, especially butyl.

The organotitanium and organochromium materials employed in the synthesis of the zeolite/organometallic compound can be prepared by reacting a titanium or chromium halide with alkyllithium compound under conditions which promote such a reaction. The alkyl moiety of the alkyllithium compound can be any group which provides upon reaction with the titanium or chromium halide an organotitanium or organochromium compound of the type hereinbefore described. Preferably such an alkyl moiety contains from 1 to about 5 carbon atoms. The molar ratio of alkyllithium compound to metal halide in the reaction medium in which such organometallic compounds are prepared generally is at least 1, prefera buy from about 1:1 to 4:1. Optionally, however, a large excess of alkyllithium compound may be employed.Thus, examples of ranges of such ratios include from about 2:1 to 50:1, and from about 3:1 to 4:1.

Reaction conditions for preparing the organotitanium or organochromium materials used herein include a reaction temperature which is low enough to maintain the stability of the organometallic compound produced. Thus, reaction temperatures will generally range from about -150 C to 50"C, preferably from about -80 C to 0 C, depending upon the temperature stability of the particular organotitanium or organochromium compound being prepared. Reaction time generally varies from between about 0.01 and 10 hours, preferably from about 0.1 to 1 hour.

Reaction conditions used in preparing the organometallic compound also generally include the utilization of an organic solvent or a reaction medium. Examples of suitable solvents include alkanes, cycloalkanes, aromatic hydrocarbons, halogenated hydrocarbons, ethers and the like. Exemplary solvent compounds include pentane, n-hexane, decane, cyclohexane, methylcyclohexane, benzene, xylenes, chloroform, diethyl ether, and mixtures of one or more of these compounds.

The organotitanium or organochromium compounds prepared as described above can be reacted with the above-described particular crystalline aluminosilicate zeolite materials to form the catalysts used in the third step of the process of the present invention. Generally, such a reaction takes place in the same reaction medium used to prepare the organometallic compound as hereinbefore described under conditions which promote the formation of such a reaction product. The zeolite can simply be added to the reaction mixture after formation of the organometallic compound has been completed. Zeolite is added in an amount sufficient to provide from about 0.1 to 10 parts by weight, preferably from about 0.5 to 5 parts by weight, of organometallic compound in the reaction medium per 100 parts by weight of crystalline zeolite.

Temperature of the reaction medium during reaction of organometallic compound with zeolite is also maintained at a level which is low enough to ensure the stability of the organometallic reactant. Thus, temperatures in the range of from about -150 C to 500C, preferably from about -80 C to 0 C can be usefully employed. Reaction times of from about 0.01 to 10 hours, more preferably from about 0.1 to 1 hour, can be employed in reacting the organotitanium or organochromium compound with the zeolite.

Upon completion of the organometallic/zeolite reaction, the catalyst material so formed may be recovered and dried by evaporating the reaction medium solvent under a nitrogen atmosphere. Alternatively, the third step reaction can be conducted in this same solvent based reaction medium used to form the catalyst.

The selection of an inert organic solvent medium to be employed in the third step of the invention when the zeolite/organometallic compound catalyst composition is used therein is not too critical, but the solvent should be inert to the supported organometallic catalyst and olefin polymer produced, and be stable at the reaction temperature used. It is not necessary, however, that the inert organic solvent medium also serve as a solvent for the polymer product of the reaction.Among the inert organic solvents applicable for such purposes are saturated aliphatic hydrocarbons having from about 3 to 12 carbon atoms per molecule, such as hexane, heptane, pentane, isooctane, purified kerosene and the like, saturated cycloaliphatic hydrocarbons having from about 5 to 12 carbon atoms per molecule such as cyclohexane, cyclopentane, dimethylcyclopentane and methylcyclohexane and the like and aromatic hydrocarbons having from about 6 to 12 carbon atoms per molecule, such as benzene, toluene, xylene, and the like.

Particularly preferred solvent media are cyclohexane, pentane, hexane and heptane.

The most preferred catalyst used in this stage of the process is boron trifluoride.

The product of the process, recovered from the third stage of the reaction, is a high quality liquid, synthetic lubricating oil having a viscosity index of at least about 90, preferably about 110 to about 300, average carbon number of at least 24, preferably 30 to 360, and average molecular weight of about 300 to about 10,000, preferably about 300 to about 5,100, and most preferably about 400 to about 2,000. The production of the high quality synthetic lubricating oil in the process of this invention from a mixture of olefins is surprising in view of the prior art teaching that good, versatile synthetic lubricating oils are produced from single pure alpha-olefin monomers, e.g., see Brennan 'Wide-Temperature Range Synthetic Hydrocarbon Fluids', Ind. Eng. Chem. Prod. Res. Dev., 1980, 19, pages 2-6.

The following Examples illustrate the invention.

Example 1 (Continuous Catalyst Preparation with Potassium Promoter) An iron solution was prepared by dissolving 18,000 g of Fe(NO3)-9H20 into 45 liters of distilled water. A copper solution consisting of 22 g Cu(NO3)2-2.5H2O in 200cc of distilled water was added and the entire solution heated to about 175OF. Separately, a 2.5 wt. % of aqueous HN3 solution was prepared. The iron solution was precipitated at about 175OF using a continuous precipitation apparatus containing a cylindrical, thermostated, well-agitated mixing zone 35 cm long and 2.5 cm internal diameter, keeping a constant pH of 6.8, measured after complete precipitation and after brief boiling of the slurry.After filtration and washing with hot water (about 150OF), a 63.75 Ib. wet cake containing 11.33 wt. % solids was obtained.

An aqueous solution (706cc) of K2CO3(8g K2COs/iiter) was added to the vigorously stirred wet cake. Finally, the wet cake was dried at 230OF, crushed to a size passing through an 8 mesh (Tyler screen) and calcined in flowing air (10cc min-' g cat-1) for 6 hrs. at 572OF. The thus-obtained catalyst composition contained about 58% by weight of iron calculated as Fe. This catalyst composition also contained about 0.2 grams of copper as Cu per 100 grams of Fe and about 0.25 grams of potassium, calculated as K2CO2, per 100 grams Fe. A sample of this material was crushed and particles having the size of about 10/30 mesh were used for catalytic testing.

Example 2 {Continuous Catalyst Preparation with Potassium Promoter) An iron solution was prepared by dissolving 21,000 g of Fe(NO3)3-9H2O into 53 liters of distilled water.

A copper solution consisting of 25 g Cu(NO3)2 2.5H2O in 250cc of distilled water was added and the entire solution heated to about 175OF. Separately, a 2.5 wt. % aqueous NH3 solution was prepared. The iron solution was precipitated at a temperature of 175OF using the continuous precipitation apparatus of Example 1, keeping a constant pH of 6.8. After filtration and washing with hot water (about 150OF), a 73.1 Ib.

wet cake containing 11.64 wt. % solids was obtained. An aqueous solution (2025cc) of K2CO3(8g K2CO3/ liter) was added to the vigorously stirred wet cake. Finally, the wet cake was dried at 230OF, crushed to through No. 8 mesh and calcined in flowing air (10cc min-' g cat-') for 6 hrs. at 572OF. The thus-obtained catalyst composition contained about 64 wt. % iron, as Fe. This catalyst composition also contained about 0.2 grams of copper (Cu) per 100 grams of Fe and about 0.6 grams of potassium, calculated as K2CO2, per 100 grams of Fe. A sample of this material was crushed and particles having the size of about 10/30 mesh were used for testing.

Example 3 (Batch Catalyst Preparation With Potassium PromoterJ A precipitated iron Fisher-Tropsch catalyst was prepared in a 3-necked, five liter, spherical, stirred reaction flask from a nitrate solution of iron and copper, using ammonia as ammonium hydroxide. A nitrate solution containing 808 grams of Fe(NO3)39H3O, in 1640 ml of deionized water, and 1.28 grams of Cu(NO3)2-3.1H2O, was precipitated at about 90"C with 8.0 moles of NH3 as a 10% by weight aqueous solution by rapid addition of the ammonia solution to the nitrate solution. The resulting gel was digested at about 96 C for 18 minutes and washed with 3 liters of hot water (about 90"C) by pouring the water through the filter cakes in two 18.5 cm Buchner funnels. The washed filter cake was then divided into six equal portions, each containing about 18 grams of iron (Fe) and about 0.05 grams of copper. One such portion was slurried in about 230 ml of deionized water, then 0.36 grams of K2CO3 was dissolved in about 170 ml of water and was added to the stirred slurry over about 2 minutes. This slurry was stirred occasionally for a period of 1/2 hour. The potassium-containing slurry was filtered, air dried at about 1200C, calcined at 3200C, and crushed to particles having the size of about 10/30 mesh of the standard Tyler mesh screen.The thus-obtained catalyst composition contained about 65% iron by weight, calculated as Fe. This catalyst composition also contained about 0.2 grams of copper, calculated as Cu, per 100 grams of iron and 2.0 grams of potassium, calculated as K2CO3, per 100 grams of iron.

Example 4 (Batch Catalyst Preparation With Cesium Promoter) An iron and copper containing composition was precipitated and washed in the apparatus and in the manner described in Example 3. The 'wet' filter cake was divided into three equal portions, each of which weighed about 380 grams and contained about 37 grams of iron as Fe. One of these portions was charged to a stainless steel mixer bowl, and a 10 ml aqueous solution containing 0.52 grams of CsCO3 was blended into the slurry. The blending continued for about four minutes. This material was then dried, calcined and sized as described in Example 3. The resulting composition contained about 65% by weight of iron, calculated as Fe, and about 0.2 grams of copper, calculated as Cu, per 100 grams of Fe and about 1.4 grams of cesium, calculated as CsCO3, per 100 grams of Fe.

Examples 5-10 (S yn gas Conversion) The catalyst compositions of Examples 1 and 2 were used to convert a syngas containing hydrogen (H2) and carbon monoxide (CO), having the mole ratio of H2/CO = 0.7.

The syngas conversion was carried out in a downflow tubular reactor at 200 psig and at the temperature and other process conditions indicated in Table 1, below. The precipitated iron catalysts of Examples 1 and 2 were diluted in 0.022 liter bed of washed, ignited sea sand. The amounts of catalyst charged into the reactor, calculated in terms of iron (Fe), are indicated in Table 1 for each example. The catalyst was activated, prior to the testing, at 280 C and 35 psi with the syngas having the mole ratio of H2/CO = 0.7 and a flow of 1 liter (STP) per gram iron per hour for about three (3) hours.

TABLE 1 Material Balance Data and Run Conditions Catalystof Example 2 1 Example 5 6 7 8 9 10 Grams of Catalyst as Fe 11.90 3.50 3.50 3.49 1.77 1.77 Temp., C 220.00 240.00 250.00 265.00 240.00 265.00 Pressure, PSIG 200.00 200.00 200.00 200.00 200.00 200.00 Feed H2/CO[MOL] 0.65 0.65 0.65 0.65 0.67 0.67 Liters H2+CO at STP/gr iron/hour (SV:NUG-Fe/Hr) 0.52 0.76 1.49 1.51 1.10 4.33 Hours on Stream 45.30 47.10 166.80 334.10 72.80 169.10 H3 + CO Converted in mole % 38.94 79.66 71.95 82.55 50.96 52.48 Effluent Composition In:H2 3.08 1.24 1.52 1.03 2.36 2.49 Weight CO 63.05 15.63 26.03 14.82 48.63 43.24 Percent CO2 21.30 61.09 53.48 63.23 32.88 39.14 H2O 3.25 1.47 1.10 0.46 3.19 1.50 HC 9.31 20.58 17.87 20.47 12.94 13.62 Hydrocarbon Selectivities, Wt Percent of HC Methane 2.25 3.36 6.84 10.51 4.03 9.68 Ethane 0.53 1.31 3.65 5.96 1.48 4.27 Ethylene 2.83 3.01 3.10 2.16 3.89 3.29 Propane 0.81 0.83 1.78 3.31 1.10 2.04 Propylene 3.71 4.74 8.25 9.75 6.51 9.96 Butane 0.61 0.71 1.53 2.50 1.05 1.88 I-butene 2.62 3.49 6.05 6.84 4.99 7.72 C0 Paraffins 86.63 82.54 68.81 58.97 76.95 61.16 Linear 1-Olefin Selectivity, Wt % of Hydrocarbons C3 2.8 3.0 3.1 2.2 3.9 3.3 C3 3.7 4.7 8.2 9.7 6.5 10.0 C4 2.3 3.3 5.4 5.6 4.5 6.7 C3 + C4 6.0 8.0 13.6 15.3 11.0 16.7 C, - C > 2 9.6 8.6 6.9 3.9 8.1 10.2 C13 - C30 10.7 10.0 4.8 1.0 9.9 0.8 C8 - C20 20.4 18.6 11.7 4.9 18.0 11.0 C2 - C20 33.6 35.0 36.9 31.8 39.2 44.8 Cs - C20 23.8 23.1 19.5 14.2 23.5 24.9 Liquid products were continuously collected in hot (about 1200C) and cold (25"C) traps at reaction pressure. Gaseous products were metered and analyzed.

Hydrocarbon liquids were analyzed using a vitreous silica capillary column (either a Scientific Glass Engineers, 50 QC2/OV-101, Pennington, N.J., or a Supelco, 30 meter SBP 5, Bellefonte, Pa. column) in a temperature programmed gas chromatograph. Individual peaks for n-paraffins, alpha-olefins, and betaolefins were resolved; the remaining peaks were summed as branched compounds.

The significant results are summarized in Figures 1-3, while the detailed results of Examples 6, 8, 9 and 10 are summarized in Figures 4-8. The distribution of alpha-olefins shifts significantly over the temperature of 220 to 265 C. This is illustrated in Figure 3 for the catalyst of Example 2. Olefin products were separated into three groups -- light olefins (C3 and C4), C8 to C,2 olefins which are suited for oligomerization to lubes, and C,3-C20 olefins which are potential detergent precursors. Each of these groups forms a modest fraction of the total hydrocarbon product as indicated below in Table 2.

TABLE 2 Effect of Temperature on l-Olefin Selectivities Within Total Hydrocarbons With Catalyst of Example 2 Temperature, C 220 240 250 265 Wt. % 1-olefin C3 3 3 3 2 C3 + C4 6 8 14 15 C8 to C12 10 9 7 4 C13 to C20 11 10 5 1 C2 to C20 34 35 37 32 For total linear olefins (Figure 3) and light olefins (Figure 2), the yield of olefins is increased by increasing reaction temperature. However, unexpectedly, the opposite trend was observed with heavy olefins, as clearly shown in Figure 1.

The olefin selectivity dependence is shown in detail for the catalysts of Examples 1 and 2 at 240"C and 265"C (Examples 6, 8, 9 and 10) in Figures 4-6. The comparison of the 240 C data for the two catalysts indicates little selectivity differences for the two potassium levels.

Detailed selectivity data for the catalysts of Examples 1 and 2 are presented in Figures 7 and 8. For the catalyst of Example 1 (about 0.2% potassium level), linear olefins comprise 60 to 40% of the products within each carbon number for the process conducted at 2400C, with about 5% selectivity of beta-olefins (or less than 10% of the linear olefins). Selectivity to beta-olefins dramatically increases at the higher temperature. The same results are observed for the catalyst of Example 2 (about 0.6% potassium level).

Examples 11-14 RSyngas Conversion; Effect of the Alkali-Promoter and Its Content on Alpha-Olefin Selectivity) The effect, if any, of the nature and the amount of the alkali metal promoter on the alpha-olefin selectivity was tested by converting the same syngas as in Examples 5-10, in the presence of catalysts having different amounts of the K2CO3 promoter (catalysts of Examples 1, 2, and 3) and of the Cs2CO3 promoter (catalyst of Example 4). The syngas was converted in the presence of these catalysts in the same tubular reactor used in Examples 5-10 at a constant temperature of 240"C, at the total reactor pressure of 200 psig, and at the varying flow rate conditions, as set forth below in Table 3.

TABLE 3 Effect of Alkali Promoter on Alpha-Olefin Selectivity Example 11 12 13 14 Catalyst of Example 1 2 3 4 Promoter K2CO3 K2CO3 K2CO3 Cs2CO3 Amount of Promoter (Grams/100g of Fe) 0.25 0.6 2.0 1.4 Liters of H3 + CO @ STP/gr Fe/Hr(SV::NUG FE/HR) 1.1 0.5 1.5 0.8 H3O CO Converted, Mole % 51.0 79.7 74.0 66.9 LinearAlpha-Olefin Selectivity, two of Hy Hydrocarbons C8-Ct2 8.1 8.6 6.4 10.6 Ct3-C20 9.9 10.0 10.3 13.2 C8-C20 18.0 18.6 16.7 23.9 C6-C26 23.5 23.1 20.3 27.6 The data of Table 3 indicates that the various types and levels of alkali promoters provide catalysts having desired olefins selectivities.

Example 15 (First Step Catalyst Preparation) An iron solution was prepared by dissolving 21,000 g of Fe(NO3)3-9H2O into 53 liters of distilled water.

A copper solution consisting of 25 g Cu(NO3)2-2.5H2O in 250 cc of distilled water was added and the entire solution heated to about 175OF. Separately, a 2.5 wt.% aqueous NH3 solution was prepared. The iron solution was precipitated at the temperature of 175OF in a continuous precipitation apparatus containing a cylindrical thermostatted, well-agitated mixing zone 35 cm long and 2.5 cm internal diameter, keeping a constant pH of 6.8, measured after complete precipitation and after brief boiling of the slurry. After filtration and washing with hot water (about 150OF), a 73.1 lb. wet cake containing 11.64 wt.% solids was obtained.An aqueous solution (2025 cc) of K2CO3 (8 g K2CO3/liter) was added to the vigorously stirred wet cake. Finally, the wet cake was dried at 230OF, crushed to through No. 8 mesh (Tyler screen) and calcined in flowing air (10cc mined g cat-1) for 6 hrs. at 572OF. The thus-obtained catalyst composition contained about 64% iron, as Fe, by weight This catalyst composition also contained about 0.2 grams of copper (Cu) per 100 grams of Fe and about 0.6 grams of potassium, calculated as K2CO3, per 100 grams of Fe. A sample of this material was crushed and particles having the size of about 10/30 mesh were used for testing.

Example 16 (Synthesis of Lubricants) Stage 1. This stage was carried out in a fixed bed reactor having a volume of 0.032 liters and containing such an amount of the precipitated iron catalyst of Example 15, diluted in sand, which had 18.9 grams of iron, calculated as Fe. A syngas comprising hydrogen and carbon monoxide (weight ratio of 0.7 H2/1 CO) was passed through the catalyst at 200 psig at a temperature of 240 to 245'C at a space velocity of 0.33 normal liters (@ STP) per gram iron per hour. Products at reactor pressure were condensed in a hot receiver at 1300C, followed by a room temperature receiver.The room temperature receiver collected about C6 to about C16 products with approximately 80% wt in the C6 to C13 range.

The material used for Stage 2 was a composite of samples taken from the cold receiver at about 55, 70 and 92 days on stream. The stage 1 reactor performance is summarized in Table 4. Compositions of the liquid products which were combined for Stage 2 are summarized in Table 5. The amounts of various fractions used in the composite sample are shown below.

Concentration of Time on Stream, each portion in total sample, Days Wt. Percent 56 19 70 13 71 32 72 15 92 11 93 10 The analysis of the composite sample by capillary gas chromatography (30 meter vitreous silica bonded phase SBP-5 column manufactured by Supelco Inc Bellefonte, Pa.) indicated that 43% of the mixture were linear alpha or beta olefins. It was estimated that about 10% of the sample was comprised of branched terminal olefins, included in the 'other' category in Table 5. The analysis of the composite sample by carbon-13 NMR spectroscopy showed a total olefin content of 52 mol%, of which 74% were terminal (alpha) olefins.

Stage 2. 41.1 g of the product from Stage 1 was stirred at room temperature for 20 hours under a stream of boron trifluoride with 0.33 grams of n-butanol as promoter. After the addition of 100 ml of hexane, the reaction was quenched with ammonia and filtered. The filtrate was washed twice with water and dried over an hydros sodium sulfate. After the removal of volatiles by rotary evaporation, 20gr of the lubricant fraction, boiling at above 580OF was obtained by vacuum distillation. The yield of lubricant was 87% based on the olefin content of the feed. Viscosity data of the lubricant is shown below.

Kinematic Viscosity, cs Viscosity at 400C at 1o0'C Index 16.37 3.73 116 TABLE 4 Stage One Reactor Summary Hours on Stream 1344 1709 2234 Temp, "C 243.00 241.00 243.00 Pressure, psig 200.00 195.00 200.00 Feed H2/CO [mol] 0.65 0.66 0.66 Liters of H2 + CO at STP/gr iron/hr (SV:NL/g-Fe/hr) 0.33 0.33 0.33 Syngas Conversion 86.34 80.27 77.82 H2 Conversion 80.54 75.08 74.59 CO Conversion 90.13 83.68 81.24 Yields in:H2 0.90 1.13 1.23 weight CO 9.81 15.74 18.02 percents CO2 66.90 62.36 60.41 H2O 0.62 0.52 0.63 HC 21.77 20.25 19.71 Hydrocarbon Selectivities, wt percent of total hydrocarbons Paraffins (P) or Olefins (O) CH4 P 7.62 9.12 11.31 C2H6 P 4.33 7.21 3.40 C2H4 0 2.03 1.58 0.51 CH8 P 2.48 3.53 1.83 C3H6 0 7.36 6.54 3.50 C4Hlo P 2.11 3.11 1.62 C4H8 0 5.94 8.49 2.94 C5+ P & 68.11 60.41 74.90 TABLE 5 (Composition in Weight % of the Liquid Products Used as Feedstock in Stage 2J Cis and Trans Normal Linear Linear Carbon No.Paraffins 1-olefins 2-olefins Other HC Sum c - 4 0.71 1.22 0.36 0.35 2.64 c - 5 2.43 2.73 0.71 0.00 5.88 c - 6 3.23 4.27 1.41 3.58 12.48 c-7 4.28 5.13 1.95 4.08 15.44 c - 8 5.62 5.53 1.66 3.73 16.55 c - 9 4.36 5.13 1.61 2.52 13.61 c - 10 3.71 2.40 1.46 3.33 10.90 c- 11 2.97 1.94 0.97 2.17 8.05 cm 12 2.23 1.24 0.68 1.59 5.75 c-13 1.41 0.71 0.51 1.17 3.79 c - 14 1.02 0.38 0.32 0.59 2.31 cm 15 0.59 0.19 0.20 0.32 1.29 c-16 0.34 0.09 0.14 0.15 0.72 cm 17 0.19 0.04 0.04 0.05 0.32 c-18 0.10 0.02 0.04 0.00 0.15 c - 19 0.05 0.00 0.00 0.01 0.06 cm 20 0.03 0.00 0.00 0.00 0.03 c - 21 0.02 0.00 0.00 0.00 0.02 c - 22 0.01 0.00 0.00 0.00 0.01 cm 23 0.00 0.00 0.00 0.00 0.00 cm 24 0.00 0.00 0.00 0.00 0.00 cm 25 0.00 0.00 0.00 0.00 0.00 C4 - 25 33.28 31.02 12.06 23.65 100.00 Average carbon number = 8 The following Examples illustrate such polymerization effectiveness.

Example 17 (Alpha-olefin Polymerization With ZeolitelOrganotitanium Compound Catalyst) A sample of HZSM-5 zeolite material (crystal size 0.05 micron, silica/alumina ratio = 70) was calcined overnight in a dry nitrogen stream at 500-540"C. A sample of the calcined solid (0.8 g.) was suspended in dry heptane.

In a separate vessel, TiCI4 (0.47 g, 2.5 m mole) contained in 10 ml of purified heptane under N2 was cooled to -78 C and 10 m moles of butyllithium (3.84 ml of 2.6N solution) was added dropwise with stirring during five minutes. The solution changed from colorless to yellow to dark brown during the addition. Stirring was continued for 20 minutes at -78 C.

A portion of this resulting butyltitanium solution (0.38 ml, 0.07 m moles) was added to the stirred mixture of 0.8 g of the HZSM-5 in 40 ml of heptane at -78 C. The resulting mixture was stirred for 30 minutes at -78 C. At the end of this time, the solution had become colorless and the zeolite had become dark brown-black in color.

This mixture was heated to 50"C, and ethylene (purified through a 25 percent solution of triethylaluminum at room temperature) was bubbled into the stirred mixture for 1 hour. During this time about 2.3 grams of polyethylene were formed.

Example 18 {Comparative Alpha-Olefin Polymerization with Silica-Supported Catalyst) For comparison purposes, a catalyst preparation reaction and an ethylene polymerization reaction similar to those of Example 17 were carried out using an amorphous silica material as the organotitanium support in place of the HZSM-5 zeolite. The silica used as the support material was a high surface area, amorphous silica (surface area = 300 m2/g.; pore volume of 1.65 cm3 per gram) marketed under the tradename Davison 952 by the Davison Division of W. R. Grace and Co.

This silica material was calcined at 540 C for 16 hours. A 0.8 g. sample of this calcined material was suspended in dry heptane, and a solution of butyltitanium in heptane (0.38 ml, 0.07 m moles) was added thereto as described in Example 17, thereby forming a black solid organotitanium/silica reaction product.

As in Example 17, the mixture was heated to 500C and ethylene (purified through a solution of triethylaluminum at room temperature) was bubbled into the stirred mixture for 1 hour. During this time, only about 0.33 gram of polyethylene was formed.

Example 19 {Comparative Alpha-Olefin Polymerization With Unsupported Organotitanium Catalyst) For further comparison purposes, a catalyst preparation reaction and an ethylene polymerization reaction similar to those of Example 17 were carried out using no silica or zeolite support at all for the butyltitanium materials formed. Accordingly, a blank run was carried out wherein the butyltitanium solution of Examples 17 and 18 (0.38ml; 0.07 m moles) was added to dry heptane (40 ml) containing no silica or zeolite.

After warming to room temperature, a fine suspension of black particles formed which did not settle.

Such a suspension formed only 0.17 gram of polyethylene under polymerization conditions comparable to those of Examples 15 and 16.

Example 20 (Alpha-Olefin Polymerization with ZeolitelOrganochromium Catalyst) An organochromium based, zeolite supported catalyst, similar to the organotitanium based catalyst of Example 17, is prepared as follows: A suspension of anhydrous CrCI2 (0.4 g, 2.5 m moles) in 10 ml of dimethylether at -78"C was reacted with butyllithium (2.8 ml of 2.3N, 7.5 m moles) added during two minutes. The mixture was stirred 20 minutes at -78 C during which time the solution became a dark yellow color. Ten ml of hexane were then added and the excess dimethylether removed under vacuum at low temperature.

Part of this solution (0.5ml) was then added to 0.8 g of HZSM-5 in 40 ml of heptane at -78 C prepared as in Example 17. The mixture was stirred for 10 minutes when the HZSM-5 had acquired a black color.

Ethylene was passed into this stirred mixture at 500C for three hours and there was then isolated 1.38 g of polyethylene.

The data from Examples 17 - 20 demonstrates that, in the ethylene polymerization screening test involved, the zeolite/organometallic catalysts employing an organotitanium or organochromium active component and an HZSM-5 zeolite support are better polymerization catalysts than the organotitanium materials which are unsupported or supported on an amorphous silica material.

Claims (29)

1 A process for the production of C5-C20 alpha-olefins comprising contacting in a reaction zone maintained at a temperature of about 200"C to about 260 C a reactants stream comprised of hydrogen and carbon monoxide with a catalyst comprising iron or a compound of iron, and recovering the product of the reaction comprising at least about 20% by weight of C5-C20 alpha-olefins.

2. A process of claim 1 wherein the reaction zone is maintained at the temperature of about 210 C to about 250 C.

3. A process of claim 2 wherein the reaction zone is maintained at the temperature of about 220"C to about 245 C.

4. A process of claim 3 wherein the catalyst comprises a sufficient amount of a promoter to enhance the activity, stability and/or selectivity of the catalyst.

5. A process of claim 4 wherein the amount of the promoter in the catalyst is about 0.05 to about 100 grams per 100 grams of the iron or compound thereof.

6. A process of claim 5 wherein the promoter is selected from at least one element or a compound of an element of the group consisting of alkali metals, alkaline earth metals, metals of Group VIA of the Periodic Chart of the Elements, titanium, zirconium, aluminum, silicon, arsenic, vanadium, manganese, copper, silver, zinc, cadmium, bismuth, lead, tin, cerium, thorium and uranium.

7. A process of claim 6 wherein the promoter is selected from at least one element or a compound of an element of the group consisting of sodium, potassium, rubidium, cesium and copper.

8. A process of claim 7 wherein the promoter is selected from at least one element or a compound of an element of the group consisting of potassium, cesium and copper.

9. A process of claim 8 wherein the amount of the promoter in the catalyst is about 0.2 to about 20.0 grams per 100 grams of the iron or compound thereof.

10. A process of claim 9 wherein the promoter is potassium carbonate and copper.

11. A process of claim 10 wherein the reaction zone is maintained at the pressure of about 50 to about 1000 psig.

12. A process of claim 11 wherein the reactants stream comprises hydrogen and carbon monoxide at the molar ratio of hydrogen to carbon monoxide of about 0.3 to about 4.0.

13. A process of claim 12 wherein the reactants stream comprises hydrogen and carbon monoxide in the molar ratio of about 0.5 to about 2.0 of hydrogen to carbon monoxide.

14. A process of claim 13 wherein the weight ratio of iron:copper:potassium carbonate in the catalyst is about 100:0.2:0.6.

15. A process of claim 14 wherein the product of the reaction comprises at least about 15% by weight of the Cs-C2g alpha-olefins.

16. A process of claim 15 wherein the weight ratio of iron:copper:potassium carbonate in the catalyst is about 100:0.2:0.25.

17. A process of claim 8 wherein the weight ratio of iron:copper:cesium carbonate is about 100:0.2:1.4.

18. A process for producing a hydrocarbon fluid comprising the steps of: (i) producing C5-C20 alpha-olefins by a process according to any one of claims 1 to 17; (ii) separating from the product of step (i) at least one hydrocarbon product having a boiling point of between about 75"F and about 600OF; and (iii) polymerizing said product in the presence of an acidic or acid-acting catalyst or at least one Zie gler-Natta polymerization catalyst.

19. A process of claim 1 wherein the acid or acidic-acting catalyst of step (iii) is selected from the group consisting of Lewis Acid catalysts, Ziegler-Natta polymerization catalysts, acid resins, solid phosphoric acid catalysts, clays, acidic amorphous porous silicates, acidic crystalline metallo-silicates and a reaction product of a crystalline aluminosilicate zeolite with an organometallic compound.

20. A process of claim 2 wherein the catalyst of step (iii) is selected from the group consisting of a Lewis Acid catalyst and Ziegler-Natta polymerization catalyst.

21. A process of claim 18, wherein in step (iii), the catalyst is selected from the group consisting of boron trifluoride, aluminum trichloride, zirconium tetrachloride, antimony pentafluoride and a highly active Ziegler-Natta catalyst of Nowlin et al.

22. A process of claim 21, wherein in step (iii), the catalyst is selected from the group consisting of boron trifluoride, aluminum trichloride, zirconium tetrachloride and antimony pentafluoride.

23. A process of claim 18, wherein the catalyst of step (iii) comprises a reaction product of (A) a crystalline aluminosilicate zeolite having a silica to alumina molar ratio of at least about 12 and a Constraint Index within the approximate range of about 1 to 12; and (B) an organometallic compound of the formula: MY,X,., wherein M is a metal selected from titanium and chromium; Y is alkyl; X is halogen; n is 1-4; and m is greater than or equal to n and is 3 or 4; under polymerization conditions which include a temperature and a pressure suitable for initiating and promoting the polymerization reaction.

24. A process according to Claim 23, wherein X is Cl or Br and Y has the formula

where R, and R2 are each selected from H and methyl; and R2 is H, alkyl, cyclohexyl, alkylcyclohexyl, cyclohexylalkyl, phenyl or alkylphenyl, benzyl and do methyl benzyl.

25. A process according to Claim 24, wherein said organometallic compound is formed by reacting a halide of a metal selected from titanium or chromium with an alkyllithium compound, wherein the alkyl group contains 1 to 5 carbon atoms, under conditions which promote such a reaction.

26. A process according to Claim 25, wherein the reaction conditions employed in forming said organometallic component include: (A) a molar ratio of alkylithium compound to metal halide of from about 1:1 to 4:1; (B) a reaction temperature of from about -150 C to 50"C; and (C) utilization of an organic solvent selected from alkanes, cycloalkanes, aromatic hydrocarbons, halogenated hydrocarbons and ethers as a reaction medium.

27. A process according to Claim 26, wherein the reaction product of organometallic compound and zeolite is produced in the same reaction medium used to form said organometallic compound.

28. A process according to Claim 27, wherein said reaction product of organometallic compound and zeolite is formed in a reaction medium which contains from about 0.1 to 10 parts by weight of organometallic compound per 100 parts by weight of crystalline zeolite, under reaction conditions which promote formation of said reaction product.

29. A process according to Claim 28, wherein said zeolite is selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48.