GB2074164A - Manufacture of Oxygenated Compounds - Google Patents

Abstract

Process of reacting carbon monoxide and hydrogen in the presence of halogen-containing ruthenium catalysts to produce acetaldehyde and ethanol. This reaction may be conducted as a first stage mainly for acetaldehyde, followed by a second stage reduction, e.g. a catalytic hydrogenation, mainly for ethanol.

Description

SPECIFICATION Manufacture of Oxygenated Compounds This invention is concerned with the production of acetaldehyde and ethanol by reaction of carbon monoxide and hydrogen in the presence of a catalyst.

Acetaldehyde is a very valuable commercial chemical with a wide variety of uses particularly as an intermediate for production of commercial chemicals. Ethyl alcohol is also an important valuable commercial chemical useful for a wide variety of purposes including as a chemical intermediate, as a solvent, and perhaps more importantly as a component of gasohol.

The reaction of carbon monoxide and hydrogen has long been known and can result in a variety of product depending on reaction conditions and the type of catalyst employed. U.S. Patent 3,833,634 describes the reaction of carbon monoxide and hydrogen over rhodium catalyst to produce ethylene glycol, propylene glycol, glycerol, methanol, ethanol, methyl acetate and other products. French Patent 2,259,077 discloses producing ethanol from carbon monoxide and hydrogen using rhodium on silica gel as catalyst at 300-3500C. and 1000-2500 psi pressure. West German Specification 2,644,185 describes conversion of carbon monoxide and hydrogen to hydrocarbons employing Ru3(CO),2 in tetrahydrofuran as solvent. Use of the same ruthenium carbonyl catalyst on solid supports to produce hydrocarbon products is described in J.A.C.S. 100, 2590 (1978).The conversion of carbon monoxide and hydrogen over ruthenium carbonyl clusters to methanol and methyl formate has been described[ACS/CSJ Chemical Congress Abstracts, INORG. 428 (1979)].

It has now been found that the reaction of carbon monoxide and hydrogen over certain ruthenium catalysts provides C2-oxygenated products, that is acetaldehyde and ethanol. The reaction apparently proceeds in several stages, with acetaldehyde being the predominant product in the early stages and ethanol predominating in later stages, so that the process can give rise to one or the other product, or mixtures of these products, which can be readily separated as by fractionation. Thus, by controlling reaction parameters, the process can be controlled to favor one or the other product, as desired.

Methanol is the principal by-product obtained in the present process.

If desired, the overall process of the invention can be conducted in separate stages, the initial stage resulting in production of acetaldehyde as the principal product, and the final stage resulting in production of ethanol as the principal product.

The process in accordance with the present invention is amenable to commercial production of acetaldehyde and ethanol, not only from the viewpoint of the yield of the products, but also the ease of recovery from the co-produced methanol, e.g., by fractional distillation. The ease of recovery is extremely important since it permits separation of the products from the reaction mixture even in those process runs where methanol may be produced in substantial amount. Thus, for example, even where acetaldehyde is present in amounts corresponding to about 10 mole-percent, and even less, of the reaction product mixture, the ease of separation will permit recovery of the aldehyde.

Acetaldehyde can be produced in a high order of purity. Usually, the initial stage reaction mixture can be used as such in the final stage reaction to produce ethanol by reduction of acetaldehyde.

The results obtainable with the present invention are indeed surprising and unexpected. In particular, ruthenium carbonyl complexes have been known to catalyze the reaction of carbon monoxide and hydrogen to form only one carbon products such as methanol, methane and methyl formate. Further, under the relatively mild reaction conditions employed in the present process, particularly the moderate reaction temperatures, ruthenium catbonyl, Ru3(CO),2, forms little if any of the C- oxygenated products of this invention.

The process of the present invention can be performed by contacting carbon monoxide and hydrogen in the presence of certain ruthenium-containing catalysts in a suitable solvent at elevated temperature and superatmospheric pressure. The major products of the reaction are acetaldehyde and ethanol, with the major by-product being methanol. The manner of contact is not critical since any of the various procedures normally employed in this type of reaction can be used as long as efficient gasliquid contact is provided. Thus, the processes may be carried out by contacting the ruthenium catalyst in reaction solvent with a mixture of carbon monoxide and hydrogen at the selected conditions. Where convenient, trickle phase operation can be used.

In view of the two-stage nature of the present process, the implementation can take several forms to produce ethanol. The reaction can be accomplished by allowing both stages to proceed consecutively at suitable temperature and pressure, or alternatively, the reaction can be stopped at the end of the first phase where the product is acetaldehyde and the second phase can be carried out under any applicable reduction process which will result in conversion of the aldehyde group of acetaldehyde to the primary alcohol group of ethanol. In most cases, however, the production of ethanol occurs quite readily. Usually, ethanol predominates as product when employing usual reaction conditions, the product mix being at least about 50/50 in most cases.

A wide variety of reduction processes can be employed for the second phase reaction including the well-known chemical reducing agents employed in reducing aldehydes to primary alcohols. For commercial processes, however, where possible, catalytic reductions employing hydrogen are usually preferred since they are more practical and efficient especially with catalysts which can be regenerated and thus are re-usable. In the present process, catalytic hydrogenation is preferred for these same reasons, especially with catalysts which can be regenerated. Any hydrogenation catalyst can be employed.

Thus, typical hydrogenation catalysts include, for example, Raney Nickel, cobalt, copper chromite, rhodium, palladium, platinum, and similar such metal catalysts, which can be used conveniently on supports such as charcoal, silica, alumina, kieselguhr and the like. The conditions of catalytic hyrogenation are well-known and, in general, the reaction can be conducted at temperatures ranging from about 300 to about 1 500C., usually at pressures of from about 100 to about 5000 psig. The use of higher temperatures and pressures, though operable, provides no special advantage and usually requires special equipment which economically is disadvantageous and therefore not preferred.

Particularly preferred hydrogenation catalysts.are those which characteristically require short reaction times, e.g., palladium and nickel, which is most desirable for commercial processes for economic reasons.

The active catalyst species of the catalyst system for the present process has not been fully identified but it is assumed to be comprised of ruthenium in complex combination with carbon monoxide together with a halide ligand. It is sufficient that the system initially comprise a source of ruthenium and a source of halide and the active catalyst species then forms on initiation of the process, e.g., the complex ruthenium carbonyl will form an addition of the reactants, i.e., carbon monoxide and hydrogen. Alternatively, the ruthenium source can be a preformed complex carbonyl. Further, the source of both ruthenium, or ruthenium carbonyl complex, and halide can be the same compound, e.g., ruthenium carbonyl halides which are commercially available.The catalyst systems can be formed with ruthenium carbonyl halides or alternatively by the combination of ruthenium carbonyl or hydrocarbonyl complexes with a separate source of halide. The catalyst systems can be employed as such or deposited or affixed to a solid support such as molecular sieve zeolites, alumina, silica, ion exchange resin or a polymeric ligand. The preferred halides are chloride and bromide. The ruthenium halocarbonyl catalysts may be represented by the formula Rua(CO)bXc wherein a, b and c are integers and X is halide. Such catalysts may be prepared by reaction of ruthenium halides with carbon monoxide or by reaction of ruthenium carbonylcomplexes with halogen-containing compounds. Alternatively, ruthenium carbonyl halides are available commercially, (e.g., from Matthey-Bishop, Malverne, PA).

The catalysts of this invention may contain other ligands in additicn to halide ligand which must be present for the present process. As described in U.S. Patent 3,833,634, suitable ligands are compounds which contain at least one nitrogen and/or at least one oxygen atom, said atoms having a pair of electrons available for formation of coordinate bonds with ruthenium. Illustrative organic ligands include various piperazines, dipyridyls, N-substituted diamines, aminopyridines, glycolic acid, alkoxysubstituted acetic acids; tetrahydrofuran, dioxane, 1 ,2-dimethoxybenzene, alkyl ethers of alkylene glycols, alkanolamines, iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetracetic acid and the like. In U.S.Patent 3,527,809 are described phosphorus-containing ligands such as trialkyl, triaryl and tricycloalkyl phophites and phosphines, as well as the analogous antimony and arsenic compounds.

Other ligands such as tin halides, e.g., SnCl,and SnBr3, or NO may be present.

The activity of the ruthenium catalyst systems of this invention may be increased by addition of alkali metal salts, particularly halide salts. in present experience, the most preferred are lithium halides, especially lithium chloride and lithium bromide. At 200 C., a LiCI/Ru ratio of 1 5 results in reduction of 40 moles CO/mole Ru/hr. with a 44% selsctivity to C2-oxygenated products. Comparative figures for lithium bromide activation were 1 3 moles CO and 44% selectivity.

For most purposes, the amount of halide employed can be varied considerably, with molar ratios of at least about 0.1 mole per mole of ruthenium being operable. The alkali metal halides may be present in large molar excess, e.g., about 11 5 mole/mole ruthenium, and even higher.

In lieu of addition of alkali metal salts, preferably halides, the salts can be used with the selected catalyst to produce ruthenium halocarbonyl anions which, for the purpose of this disclosure, are represented by the general formuia MaRubXc(CO)d wherein a, b, c and d are integers, e.g. NaRuBr3(CO)3 and NaRuCl3(CO)3. Such compounds can be preformed and then added to the reaction in solvent as the catalyst system.

The hydrohalic acids HCl and HBr can promote the activity of the ruthenium halocarbonyls of the present new process but to a lesser extent than alkali metal halides. The addition of HCl increased the catalytic activity of [RuCl2(C03]2 only to about 25% that of lithium chloride with a decrease of selectivity to ethanol and acetaldehye, while both HCI and HBr promoted the activity of Ru3(CO)12.

Large excesses of hydrogen halides are of no advantage and are usually avoided since they may tend to decrease catalyst activity.

In addition, the catalyst systems for this invention can also be formed by addition of halide to a suitable ruthenium compound in the selected solvent or in the reaction mixture, if preferred. For example, ruthenium acetylacetonate in combination with hydrogen halide in reaction solvents provides essentially the same results as preformed catalyst, e.g. [Ru(CO)2C1]2. It is noted that, in the absence of halide, e.g. chloride or bromide, the ruthenium catalysts such as ruthenium carbonyl form methanol as the principal product with negligible or trace amounts of ethanol or acetaldehyde. The amounts of halide added to the catalyst need not be stoichiometric since even small amounts will result in the production of some ethanol.For most purposes, however, it is preferred to employ at least an equimolar amount of halide which can be added as aqueous solution, e.g. hydrohalic acid, or solution in organic solvents such as the lower alkanols.

When lithium chloride was employed at equimolar ratios with Ru3(CO)12, at 2000 C, 13 moles CO/mole Ru/hr. were reduced with a selectivity to two-carbon products of 48%. With excess lithium bromide (~60 moles/mole Ru) at 2500C., enhanced productivity to two-carbon products was observed.

The determination suitabiiity of starting ruthenium compounds to be used for in situ formation of the halide-containing catalyst can be accomplished by a simple test procedure which involves running smail scale reactions with the selected ruthenium compound, halide and reactants CO and H2 in solvent. At the completion of the miniature reactions, gas-liquid chromatographic analyses of the reaction mixture will identify the products and, of course, will identify those ruthenium compounds which are suitable, through in situ treatment, for production of ethanol and/or acetaldehyde. Using this test procedure, suitable starting ruthenium compounds are easily identified.

When acetaldehyde is the desired product, of course, only the first stage reaction need be carried out. The product can be separated from the co-produced methanol, any ethanol formed and reaction solvent, if necessary, by fractional distillation.

As should be apparent, the ruthenium catalyst employed in the first stage reaction can also serve as a hydrogenation catalyst for the second stage reaction to produce ethanol. Thus, if the first phase reaction is allowed to continue, eventually the hydrogenation reaction will yield ethanol. In general, the ruthenium catalyst of the first stage reaction is an effective catalyst for the second stage hydrogenation, but other hydrogenation catalysts can be used in lieu of the ruthenium catalyst. If desired, the ruthenium catalyst can be converted to a more effective hydrogenation catalyst by addition of a phosphine ligand, particularly triaryl phosphines such as triphenylsphosphine, although other phosphine ligands as described in U.S. Patent 3,527,809, can be used as well.

It is possible to effect the reduction step over metal catalysts such as palladium and nickel, or copper chromite and to effect the second stage reaction in a separate reactor. Thus, the first stage reaction can be conducted in a first reactor under selected conditions of temperature and pressure, and after completion the first stage product, with or without isolation from the reaction mixture, can then be transferred to a second reactor under selected conditions of temperature and pressure to effect the hydrogenation reaction.

There of course is no criticality about stopping the reaction exactly at the termination of the first stage, or holding the second stage reaction until all acetaldehyde is reduced to ethanol. The reaction can be stopped at any convenient point which will be dictated by the product desired, along with other considerations. Thus, after substantially maximum yield of acetaldehyde is obtained, usually within about 2 hours, the reaction can be stopped and the aldehyde recovered. However, the reaction mixture will undoubtedly contain quantities of ethanol formed through the second stage reaction. The products, however, are easily separable and are almost equally commercially important.Obviously, where ethanol is desired, the reaction can be allowed to proceed, within economic considerations, until reasonably complete to obtain ethanol as the major product, and of course acetaldehyde the minor product.

The present invention, therefore, provides a simplified process for production of acetaldehyde. In addition, this invention affords a simplified process for obtaining ethanol by either allowing the initial process for aldehyde production to continue so that hydrogenation yields ethanol or, alternatively, the aldehyde product of the first stage reaction is reduced employing art-recognized reduction processes to ethyl alcohol. In the latter process, the acetaldehyde product of the first stage reaction can be used in the form of the reaction mixture, or the product can be isolated, as by fractionation, and used in purified form.

The amount of catalyst employed in the present process does not seem to be critical and can vary considerably. At least a catalytically effective amount of catalyst should be used, of course. yin general, an amount of catalyst which is effective to provide a reasonable reaction rate is sufficient. As little as 0.001 gram atoms ruthenium per liter of reaction medium can suffice while amounts in excess of 0.1 gram atoms do not appear to materially effect the rate of reaction. For most purposes, the effective preferred amount of ruthenium is in the range of from about 0.002 to about 0.05 gram atoms per liter.

The reaction conditions are not overly critical in that wide ranges of elevated temperature and superatmospheric pressures are operable. The practical limitations of production equipment will dictate to a great extent the selection of temperatures and pressure at which the reaction is to be effected.

Thus, using available production systems, the selected elevated temperature should be at least about 1 500 C. and can range up to about 3000 C. For most purposes, the preferred operating temperature ranges from about 1750 to about 2750C. The superatmospheric pressure should be at least about 10 atmospheres and can range up to almost any pressure attainable with production apparatus. Since extremely high pressure apparatus is quite expensive, pressures to about 700 atmospheres are suggested. Most desirably, the pressure should be in the range of from about 1 50 to about 400 atmospheres, particularly when employing the aforesaid preferred temperature range.

The reaction is preferably carried out in a solvent which will dissolve polar materials and which preferably is aprotic. The preferred solvents are N-substituted amides in which each hydrogen of the amido nitrogen is substituted by a hydrocarbon group, e.g., 1 -methyl-pyrrolidin-2-one. N,N dimethylacetamide, N,N-diethylacetamide, N-methylpiperidone, 1 ,5-dimethylpyrrolidin-2-one, 1 - benzyl-pyrrolidin-2-one, N,N-dimethylpropionamide, hexamethylphosphoric triamide and similar such liquid amides. The amides are preferred solvents since their use results in the highest yields of product in present experience. Other solvents, usually aprotic, can be used but the yields are substantially less than obtained with the preferred amide solvents.Such solvents include, for example, cyclic ethers such as tetrahydrofuran, dioxane and tetrahydropyran; ethers such as diethyl ether, 1 ,2-dimethoxybenzene; alkyl ethers of alkylene glycols and polyalkylene glycols, e.g., methyl ethers of ethylene glycol, propylene glycol and di-, tri- and tetraethylene glycols; ketones such as acetone, methyl isobutyl ketone, and cyclohexanone; esters, such as ethyl acetate, ethyl propionate and methyl laurate; and alkanols, such as methanol, ethanol, propanol, 2-ethylhexanol and the like; tetramethylurea; ybutyrolactone; and mixtures thereof. The selected solvent should preferably be liquid under the reaction conditions.

The preferred solvents are aprotic orgnic amides. The contemplated amides include cyclic amides, i.e., in which the amido group is part of a ring structure such as in pyrrolidinones and piperidones; acylated cyclic amines, such as N-acyl piperidines, pyrroles, pyrrolidines, piperazines, morpholines, and the like, preferably in which the acyl group is derived from a lower alkanoic acid, e.g., acetic acid; as well as acyclic amides, i.e., wherein the amido group is not part of a ring structure as in acetamides, formamides, propionamides, caproamides and the like. The most preferred of the amides are those in which the amido hydrogen atoms are fully replaced by hydrocarbon groups preferably containing not more than 8 carbon atoms.Exemplary hydrocarbon groups are alkyl, preferably lower alkyl such as methyl, ethyl and butyl; aralkyl, such as benzyl and phenethyl; cycloalkyl, such as cyclopentyl and cyclohexyl; and alkenyl, such as allyl and pentenyl. The preferred amido nitrogen substituents are lower alkyl, especially methyl, ethyl and propyl groups and aralkyl groups, especially benzyl. The most preferred amide solvents include 1 -methylpyrrolidin-2-one, 1 -ethylpyrrolidin-2-one, and 1-benzylpyrrolidin-2-one. Of course, mixtures of the solvents can be used, e.g. amide solvent with other solvent(s).

Water is not critical to the reaction and can be present without serious adverse effect. It tends to react with carbon monoxide to form CO2 and hydrogen (water gas shift). Water can be excluded since it can reduce the selectivity of conversion of carbon monoxide, or the water-gas shift can be used advantageously to generate hydrogen.

The reaction pressures represent the total pressure of the gases contained in the reactor, i.e.

carbon monoxide and H2, and, if present, any diluent gas such as nitrogen. As in any gaseous system, the total pressure is the sum of partial pressures of component gases. In the present reaction, the molar ratio of hydrogen to carbon monoxide can range from about 1/10 to about 10/1 , with the preferred ratio, from about 1/5 to about 5/1, and the reaction pressure can be achieved by adjusting the pressure of these gases in the reactor.

Where the second phase reaction is carried out in a separate reactor whether over the originally present ruthenium catalyst or a different metal hydrogenation catalyst, the reaction is normally conducted under hydrogen gas without diluent gas, as is usual in catalyzed hydrogenation reactions.

As with any process of this kind, the present process can be conducted in batch, semicontinuous, and continuous operation. The reactor should be constructed of materials which will withstand the temperatures and pressures required, and the internal surfaces of the reactor are substantially inert. The usual controis can be provided to permit control of the reaction such as heatexchangers and the like. The reactor should be provided with adequate means for gas-liquid contact such as shaking, stirring, oscillation, trickle column operation and like methods. Catalyst as well as reactants may be introduced into the first stage or the second stage reactor at any time during the process for replenishment. Recovered catalyst, solvent and unreacted starting materials may be recycled.

The relative yields of ethyl alcohol, actaldehyde and methanol are not overly critical since the product mixture can be readily separated into the components by known techniques, especially by fractional distillation, regardless of the proportions contained in the mixture. Therefore, even where the desired product is 1020% of the reaction mixture, it can be readily separated from the mixture, especially under continuous processing. Of course, the preferred processes yield mixtures in which acetaldehyde and ethanol predominate as the reaction product and methanol, as a by-product, is minimal.

The process conditions for the separate first stage reaction are essentialiy the same as employed in the first stage of the combined two-stage reaction. Thus, the reaction is carried out at a temperature of at least about 1 500C. to obtain a reasonable reaction rate and up to about 3000 C. For best results, the temperature should be in the range of about 1 750C. to about 2750C. The total pressure of gas used is generally maintained at from about 10 up to about 700 atmospheres, with from about 1 50 to about 600 atmospheres being preferred. Of course, high pressures and higher temperatures can be used but with no appreciable advantage and, since they require the use of special high pressure equipment, they are usually avoided.

The reaction conditions employed in the second reaction stage, i.e. the hydrogenation, can be any of the standard reaction temperatures and pressures employed for such reactions since neither temperature nor pressure is critical for this reaction. Preferably, the hydrogenation is conducted at a temperature of at least about 100 C. in order to effect a reasonable reaction rate. Of course, lower temperatures can be used if longer reaction times can be tolerated. The pressure of hydrogen gas is not excessively critical as long as sufficient gas is available for the hydrogenation. For convenience, the pressure will range from about 500 psi to as much as 5000 psi, although even higher pressures can be employed.

When the catalyst selected for the hydrogenation step is other than ruthenium, it is preferred to remove the ruthenium catalyst from the first stage reaction mixture. This preference is primarily predicated on the desirability of avoiding concomitant catalytic effects which may tend to reduce the yield of ethanol.

The following examples further illustrate the invention. The equipment, synthetic procedure and analyses employed are as follows: I. Equipment A. Reactors Reactions were carried out in Parr 71 ml reactors constructed of 310SS having one Type A 1/4" coned socket (Cat. #4740, Parr Instrument Co., Moline, IL). Glass liners with open tops were employed. Reactor seal was a modified Bridgeman type, incorporating a special two piece gasket (Cat.

#61 HD), comprising silver (exposed to process) with a nickel back-up ring. This gasket arrangement was necessitated due to attack by carbon monoxide on the originally supplied one-piece nickel gasket.

The reactors were capped with 31 6SS Whitey severe service valves with high temperature Grafoil packing (Cat. #SS3NBS4-GTA-9K-3N, Whitey Co., Oakland, CA). The valves were coupled to the reactors with 316SS Sno-Trik male high pressure to Swagelok adapters (Cat. #SS-44M-A-400, Sno Trik Co., Solon OH) and Swagelok port connectors (Cat. #SS-401-PC, Crawford Fitting Co., Cleveland, OH).

B. Agitation and Heating The arm of a Burrell wrist action shaker was projected into an oven comprising an insulated box and electrical strip-heaters. Reactors were clamped to the shaker arm. Oven temperature was measured by a thermocouple which connected to a controller (on-off type). A timer was used to control reaction time by interrupting power to the temperature controller at the desired time. The temperature controller was used to activate a relay coil. A Variac was used to regulate the voltage going to the heater from the relay.

In cases where more vigorous agitation was required, the reactors (without glass liners) were bolted to a paint shaker by means of a special bracket which prevented whip action of the valve which would cause the port connector to sever.

C. Gas Compression and Delivery Custom carbon monoxide-hydrogen mixtures (Union Carbide Corp., Linde Division, South Plainfield, NJ) were piped into an air driven, double-ended compressor (Cat. #4614035, American Instrument Co., Silver Spring, MD), thence to the reactor through a iine containing shut-off and vent valves and a pressure gauge.

II. Synthesis Procedure Reactor charging and sealing generally were carried out in a nitrogen atmosphere (glove bag).

Catalyst (about .02 gm) and additives were weighed into a glass liner which then was placed in the reactor. Solvent (5 ml) and liquid additives (usually air free) were added by syringe or pipette. The reactor was sealed and capped with a valve.

The reactor was connected to the compressor discharge system and purged with the desired gas by pressurizing, then venting several times. Then gas was compressed into the reactor to the desired pressure (20004500 psig) as indicated on the system gauge. After gays feed-line venting, the reactor was disconnected, and the valve plugged to prevent leakage through the seal.

After heating (80--2500C.) and shaking the reactor for the desired time, it was cooled then vented through a wet test meter with a gas sample being taken. The liquid contents were discharged, and the reactor and liner rinsed with solvent. The combined liquid for analysis was 1 5 gm.

III. GLC Analysis Procedure GLC analyses were performed on a Varian-Aerograph Series 1400 Chromatograph equipped with hydrogen flame detector. A 6'x1/8" O.D.316SS column packed with 80-100 mesh Chromosorb 101 was utilized. The column was operated at 100 C. for 9 minutes then temperature was increased by 6 C/min. to 2000C. This procedure provided reproducable isothermal analysis of lower boiling components and decreased retention times for higher boiling materials.

IV. Product Identification The components of the reaction mixtures employing Ru catalysts were identified by GLC-MS analysis. Besides the major products-methanol, ethanol and acetaldehyde-several other components were found. These were formaldehyde, ethylene glycol, propionaldehyde, n-propanol, acetic acid, methyl acetate, 1,3-dioxolane, 2-methyl-1,3-dioxolane hydroxy-2-propanone and 1,2-propanediol. In a few cases, methane was observed.

Example 1 Using the described Synthesis Procedure, the catalysts produced with various alkali metal chlorides and Ru3(CO)12 were evaluated using the following materials and reaction conditions: 0.093 mmole Ru 0.093 mmole salt 1.5:1 HCO at 4500 psig (200C) 5 ml N-methylprrolydin-2-one The reaction was conducted at 200 C. for two hours.The results are given in Table Table I Turnover Number Products, mmoles Product Moles Product/Mole Ru Mole Ratio Salt CH3OH CH3CHO C2H50H cl/C2 C1 C2 O 0 0 - 0 0 LiCI 1.25 .47 .10 2.2 13 6.1 NaCI .75 .15 tr. 5.0 8.1 1.6 KCI .37 .11 - 3.4 4.0 1.2 RbCI .57 .20 - 2.8 6.1 2.2 RbCl(1) .74 tr. tr. - 8.0 CsCI .48 .07 ~ 6.8 5.2 .8 (1) .5 mmole salt Example 2 Various catalysts formed in situ from lithium salts and Ru3(CO)12 were evaluated using the same procedure as in Example 1 excepting the salts were added at a level of 0.1 mmmole.

The results are given in Table II.

Table II Turnover Number Products, mmoles Product Moles Product/Mole Ru Mole Ratio Salt CH3OH CH3CHO C2H5OH C1/C2 C1 C2 0 0 0 0 - 0 O LiF(1) tr. O 0 - tr. 0 LiCI 1.25 .47 .10 2.2 13 6.1 LiBr .51 .27 0 1.9 5.5 2.9 LiBr (2) 1.59 tr. .06 27 17 .6 Lil .30 .05 0 6.0 3 .5 LiOAc .16 tr. O 1 - Li2CO3 0 0 0 0 0 0 (1) .15 mmole (2) .6 mmole Example 3 Various catalysts formed with hydrogen halides and Ru3(CO)12 were evaluated using the procedure of Example 2. In addition. the effect of hydrogenhalides on preformed ruthenium chlorocabonyls was also evaluated using the same procedure.

The results are shown in Table Ill.

Table III Turnover Number Products, moles Product Moles Product/Mole Ru Mole Ratio Catalyst Acid CH3OH CH3CHO C2H50H Ct/C2 C1 C2 RU3(CO)12 O 0 0 0 - 0 O Ru3(CO)12 HCI .65 .16 .12 2.3 7.0 3.0 Ru3(CO)12 HBr .66 .32 .20 1.3 7.1 5.6 Ru3(CO)12 Hl(1) 0 0 0 - - - [RuCl2(CO)3]2 - 1.2 .20 .20 3.0 12 4 [RuCl2(CO)3]2 HCI 2.0 tr. .26 7.7 20 2.6 [RuCl2(CO)3]2 HBr 1.4 tr..23 6.1 14 2.3 [RuCl2(CO)3]2 HI 0 0 0 - - (1) 8 mmoles HI Example 4 The effect of increasing lithium chloride molar ratio was evaluated using the procedure of Example 2 with the results given in Table IV, with [Ru(CO)3Cl2]2 preformed catalyst.

Table IV Turnover Number Moles LiCI Products, moles Product Moles Product/Mole Ru Mole Ratio Mole Ru CH3OH CH3CHO C2H5OH C1/C2 C1 C2 0 1.18 .20 .20 2.9 12 4.1 .9 2.44 .37 .43 3.0 25 8.2 2.0 3.05 .51 .55 2.9 31 11 7.7 4.08 .62 .88 2.7 42 15 15 4.41 .62 1.1 2.6 45 17 Example 5 Various temperature, catalyst and additive effects on the reaction were evaluated using the procedure of Example 1.

The results are given In Table V.

Table V Turnover Number Mole P Products, mMoles Product Moles Product/Mole Ru Mole Ratio Catalyst Promoter, P Mole Ru Temp., C CH3OH CH3CHO C2H5O C1/C2 C1 C2 Ru3(CO)12 - - 175 0 0 0 0 0 0 Ru3(CO)12 - - 200 .05 0 0 - .5 0 Ru3(CO)12 - - 250 .47 0 0 - 5.0 0 Ru3(CO)12 LiCl 1 175 .38 .29 0 1.3 4.1 3.1 Ru3(CO)12 LiCl 1 200 1.25 .47 .10 2.2 13.4 6.1 Ru3(CO)12 LiCl 16 250 25 0 .24 104 263 2.5 Ru3(CO)12 HBr 1 185 .24 .11 .16 .9 2.6 2.9 Ru3(CO)12 HBr 1 200 .66 .32 .20 1.3 7.1 5.6 Ru3(CO)12 HBr 1 250 11.0 0 .44 25 118 4.7 [RuCl2(CO)3]2 - - 150 tr. tr. tr. - tr. tr.

[RuCl2(CO)3]2 - - 175 .26 tr. .10 2.6 2.6 1.0 [RuCl2(CO)3]2 - - 200 1.20 .20 .20 3.0 12.2 4.1 [RuCl2(CO)3]2 - - 250 7.6 tr. .32 24 78 3.3 [RuCl2(CO)3]2 LiCl 7.5 185 1.4 .32 .47 1.7 14 8.1 [RuCl2(CO)3]2 LiCl 7.7 200 4.1 .62 .88 2.8 42 15 [RuCl2(CO)3]2 LiCl 15 200 4.4 .62 1.1 2.6 45 18 [RuCl2(CO)3]2 LiCl 15 250 23.2 0 1.32 18 237 13 [RuCl2(CO)3]2 LiBr 15 200 1.47 .30 .27 2.6 15 5.8 [RuCl2(CO)3]2 LiBr 15 250 11.7 .27 1.96 5.2 119 23 [RuCl2(CO)3]2 LiBr 58 250 14.5 .35 3.96 3.4 148 44 [RuCl2(CO)3]2 LiBr 115 250 8.0 .47 4.99 1.5 82 56 [RuCl2(CO)2(Ph3P)2 LiCl 1 200 1.02 tr. .03 34 10.4 .31 [RuCl2(CO)2(Ph3P)2 LiCl 1 250 5.8 tr..09 64 59.2 .92 (SnCl3)Ru2Cl3(CO5) - - 200 .89 .08 .16 3.7 9.1 2.4 (SnCl3)Ru2Cl3(CO5) LiCl 54 200 4.36 .81 1.71 1.7 44 26 Referring to Table V, it is noted that the use of higher reaction temperature over 2000C. and preferably above 2250C., results in significant increases in methanol production and, in some cases, in extremely high selectivities to methanol, as evidenced by the Product Mole Ratio C,/C2 values, and the Turnover Number values. This increase in methanol production is further enhanced by added halide, especially chlorides which generally appear to be more effective than other halides in this regard.

The combination of increased reaction temperature and addition of halide, i.e., metal halide and/or hydrogen halide, in present experience gives the best productivities to methanol and therefore comprises a particularly preferred embodiment of this aspect of the present new process.

Example 6 Ruthenium and rhodium chlorocarbonyls are compared with and without lithium chloride as a promoter in the procedure of Example 1 with the results given in Table VI.

From these data, it is apparent that lithium chloride does not promote but rather inhibits the rhodium catalyst.

Table VI Turnover Number Product Yields, mMoles Moles Product/Mole Metal mMole Catalyst Metal Additive, mMole Temp., C CH3OH C3CHO C2H5OH C1 C2 [Rh(CO)2Cl]2 .129 - - 175 .066 .012 .046 .5 .4 [RuCl2(CO)3]2 .098 - - 175 .26 tr. .10 2.6 1.0 [Rh(CO)2Cl]2 .129 LiCl .129 200 .023 .013 0 .2 .1 [RuCl2(CO)3]2 .098 LiCl .098 200 2.44 .37 .43 25 8.2 [Rh(CO)2Cl]2 .129 - - 200 .24 tr. .056 1.9 .4 [RuCl2(CO)3]2 .098 - - 200 1.18 .20 .20 12 4.1 [Rh(CO)2Cl]2 .129 LiCl .75 200 0 0 0 0 0 [Rh(CO)2Cl]2 .098 LiCl .75 200 0 0 0 0 0 [RuCl2(CO)3]2 .098 LiCl .77 200 4.08 .62 .88 42 15 Example 7 Various preformed ruthenium halocarbonyl anions were evaluated using the procedure of Example 1 with the results given in Table VII. The alkali metal salt and ruthenium carbonyl halide of Example 1 are replaced by the indicated anionic complex.

Table VII Yields (mmole) Catalyst Additive T( C.) MeOH CH3CHO EtOH CH4 CsRu(CO)3CI3 - 250 8.4 .22 .54 0 CsRu(CO)3CI3 CsBr 250 6.5 .28 .54 .5 (1.5 mmoles) Cs2Ru(CO)3Cl4 - 250 9.1 .2 .56 .8 Cs2Ru(CO)3CI4 CsBr 250 9.0 tr. .97 1.2 (1.5 mmoles) K2Ru(NO)CI5 - 200 1.2 .31 .37 .4 K2RU(No)cl6 - 250 7.1 tr. 4.3 6.8 LiRu(CO)3Cl3 - 200 2.7 .77 .71 0 LiRu(CO)3C13 - 250 7.7 tr..58 0 LiRu(CO)3Br3 - 200 1.4 .25 .5 0 LiRu(CO)3Br3 - 250 11 .37 1.5 1.9 CsRu(CO)3Cl3 - 200 1.0 .22 .21 0 Cs2Ru(CO)2Cl4 - 200 .93 .14 .26 0 Example 8 The procedure of the preceding examples was repeated employing HBr or HCI with Ru3(CO),2 (at 0.093 mmole Ru) and with H4Ru4(CO),2 (at 0.1 mmole Ru) at H2/CO of 1.5:1 and initial pressure of 4500 psig for two hours at the indicated temperatures. The results are given in Table VIII.

Table VIII

Yields (mmole) Catalyst Additive T( C.) MeOH CH3CHO ETOH CH4 H2RU4(Co)12 HBr 200 .51 .23 .24 0 (.1 mmole) H2Ru4(CO)12 - 200 .06 tr. tr. O Ru3(CO)12 HBr . 200 0 0 0 0 (.5 mmole) Ru3(CO),2 HBr 200 .55 .17 .15 0 (.1 mmole) Ru3(CO)12 - 200 .05 0 0 0 RU3(Co)12 HCI 200 .65 .16 .12 0 (.1 mmole) RU3(Co)12 HBr 200 .66 .32 .2 0 (.1 mmole) Ru3(CO)12 HBr 200 .5 .35 .18 0 (.1 mmole) Ru3(CO),2 HBr 200 .89 tr. .55 0 (.2 mmole) Ru3(CO)12 HBr 185 .24 .11 .16 0 (.1 mmole) RU3(Co)12 HBr 250 11 0 .44 1.1 (.1 mmole) LiCI Ru3(CO)12 # (.1 mmole) 200 2.0 .89 .42 0 HBr t(.1 mmole) Ru3(CO)12 HBr 175 .15 .04 .14 .98 (.1 mmole) LiBr (5.8 mmole) Ru3(CO)12 HBr 200 3.2 .56 .24 0 (.1 mmole) Ru3(CO)12 " 250 14.9 .08 2.19 6.1

Claims (33)

Claims

1. A process for producing acetaldehyde and/or ethanol which comprises reacting carbon monoxide and hydrogen at elevated temperature and superatmospheric pressure in the presence of a ruthenium-containing catalyst, the reaction system initially containing a source of ruthenium and a source of halide.

2. A process according to claim 1 wherein preformed ruthenium carbonyl halide is present in the reaction system.

3. A process according to claim 1 or 2 wherein ruthenium carbonyl halide is formed in situ from feed carbon monoxide.

4. A process according to any of claims 1 to 3 wherein the elevated reaction temperature is from about 1 500C to about 3000 C.

5. A process according to any of claims 1 to 3 wherein the elevated reaction temperature is from about 1 750C to about 2750C.

6. A process according to any of claims 1 to 5 wherein the superatmospheric reaction pressure is about 150 to about 600 atmospheres.

7. A process according to any of claims 1 to 6 wherein the molar ratio of hydrogen to carbon monoxide is from about 1/10 to about 10/1.

8. A process according to any of Claims 1 to 7 wherein the reaction system contains an alkali metal chloride or bromide.

9. A process according to any of Claims 1 to 8 wherein the reaction system contains hydrogen chloride or hydrogen bromide.

10. A process according to Claim 8 wherein the alkali metal is lithium.

11. A process according to any of Claims 1 to 10 wherein the reaction is carried out in the presence of a solvent comprising an aprotic organic amide.

12. A process according to Claim 11 wherein the solvent comprises an N-lower alkyl pyrrolidin-2one.

13. A process according to Claim 11 wherein the solvent comprises an N,N-di(lower alkyl) acetamide.

14. A process according to Claim 11 wherein the solvent comprises N-methyl pyrrolidin-2-one.

1 5. A process according to Claim 11 wherein the solvent comprises N,N-diethyl acetamide.

1 6. A process according to Claim 11 wherein the solvent comprises N,N-diethyl propionamide.

1 7. A process according to any preceding claim wherein the reaction system initially contains an organic compound having at least one nitrogen and/or at least one oxygen atom for co-ordination with ruthenium.

1 8. A process according to any preceding claim wherein the reaction system initially contains an organo-phosphorus, -antimony or -arsenic compound.

19. A process according to any preceding claim which is conducted as a first reaction stage and is followed by a second reaction stage which is an ethanol-producing reduction stage.

20. A process according to claim 1 9 wherein said ruthenium is present during said second reaction stage.

21. A process according to claim 19 wherein the second stage reaction is a catalytic hydrogenation reaction.

22. A process according to claim 21 wherein a hydrogenation catalyst comprising palladium is used in the second stage.

23. A process according to claim 20,21 or 22 wherein said ruthenium is removed from the first reaction stage product prior to the second stage reaction.

24. A process for the production of acetaldehyde and/or ethanol, the process being substantially as hereinbefore described in any Example.

25. A process for producing acetaldehyde and/or ethanol which comprises reacting carbon monoxide and hydrogen in the presence of a source of ruthenium and a source of halide.

26. A process for producing acetaldehyde and/or ethanol which comprises reacting carbon monoxide and hydrogen in the presence of a ruthenium carbonyl halide catalyst.

27. A process for producing acetaldehyde and/or ethanol by reacting carbon monoxide and hydrogen using a halogen-containing ruthenium catalyst.

28. A process for producing acetaldehyde and/or ethanol which comprises reacting carbon monoxide and hydrogen at a temperature of from about 1500 to about 3000C. and superatmospheric pressure in the presence of a catalyst system initially comprised of a source of ruthenium and a source of halide and recovering acetaldehyde and/or ethanol from said reaction.

29. A process according to claim 28 wherein acetaldehyde is formed in a first reaction stage and then ethanol in a second reaction stage, wherein the catalyst system is present at least during said first reaction stage.

30. A process according to claim 29 wherein said ruthenium is present during said second reaction stage.

31. A process according to claim 29 wherein a hydrogenation catalyst is present during said second stage reaction.

32. A process according to claim 31 wherein said ruthenium is removed from the first reaction stage product prior to said second stage reaction.

33. Acetaldehyde and/or ethanol obtained by a process according to any of claims 1 to 32.