NL7906415A - PROCESS FOR PREPARING ALIPHATIC CARBONIC ACIDS AND THE ESTER DERIVATIVES THEREOF. - Google Patents

Description

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-1- 20879 / Uk / iv

Applicant: Texaco Development Corporation, White Plains, New York, United States of America.

Short designation: Process for the preparation of aliphatic carboxylic acids and their ester derivatives.

5

The invention relates to a process for the preparation of aliphatic carboxylic acids and their ester derivatives with two or more carbon atoms, starting from an aliphatic alcohol and / or ester reactant of the formula ROH and R'-C (sO) -OR, wherein R and R 'are saturated hydrocarbyl radicals with 1-12 carbon atoms. In particular, the invention relates to a process for the selective synthesis of aliphatic carboxylic acids and their esters from aliphatic alcohols by reaction with carbon monoxide in the presence of a ruthenium-containing catalyst and a halogen-containing promoter. Reaction equation 11 below lists this process, where R is a linear, branched chain or a cyclic saturated hydrocarbyl radical containing 1-12 carbon atoms. The carbonylation of methanol to acetic acid is a specific example of this general synthesis.

ROH + CO-RC00H 1.

A large number of aliphatic carboxylic acids with different number of carbon atoms and different structures are important materials today. Acetic acid production today exceeds 1 billion kg per year in the United States as noted in "Trends in Petrochemical Technology", A.M. Brownstein (1976), Chapters 4 and 5 and "Petrochemicals 25 from Coal", P.M. Spitz, Chemtech, May 1977, biz. 295. Important uses for this acid are the production of cellulose acetate and vinyl acetate.

There are several partially important pathways for the preparation of acetic acid, including the oxidation of ethylene via acetaldehyde, the liquid phase oxidation of saturated hydrocarbons, the oxidation of n-butene and the carbonylation of methanol. Since methanol is now also prepared from synthesis gas (a mixture of CO and hydrogen), the synthesis of acetic acid via the methanol carbonylation becomes effective and falls under the "syngas" chemistry. Because syngas can be obtained from a variety of sources including heavy oil residues and coal as indicated in "Trends in Petro-35 chemical Technology", A.M. Brownstein (1976), chapters 4 and 5, and in 7906415 1. -2- 20879 / Vk / iv / "Petrochemicals from Coal ,.", P.M. Spitz, Chemtech, May 1977, biz. 295, the syngas pathway to obtain acetic acid is gaining importance because petroleum is deficient.

The carbonylation process for the preparation of carboxylic acids from alcohols is known to the extent that they are directly aimed at the preparation of acetic acid by the carbonylation of methanol. In particular, a number of soluble forms and shapes on cobalt, nickel, iron, iridium and rhodium supports have been published as catalysts for the carbonylation of methanol to acetic acid. In the known processes with *. with regard to carbonylation, the metal carbonyl compounds or modified metal carbonyl compounds of cobalt, iron and nickel are used, it being necessary to use high pertial pressures of carbon monoxide in order to keep the carbonyl compounds stable at temperatures above 200 ° C, which normally become normal. used as described in "Carbon Monoxide in Organic Synthesis", J. Falbe 15 (1967), Chapters II and III. For example, when using dikobalt octacarbonyl, it is necessary to use a partial carbon monoxide pressure of 270 to 700 atmospheres. Furthermore, the cobalt, nickel, and iron catalysts used heretofore have relatively poor selectivity to the desired carboxylic acid due to the relatively large amount of unwanted by-products that are formed. These by-products include significant amounts of ethers, aldehydes, higher carboxylic acids, carbon dioxide, methane and water as indicated by N. von Kutepow et al., Chemie-Ing. Techn. 37, 383 (1965).

More recently, a number of highly active carbonylation catalysts have been described, such as in Belgian Patent 713,296, U.S. Patent 3,772,380 and 3,717,670, wherein the active ingredients contain a rhodium or iridium component in combination with a halogen promoter. These catalyst combinations are characterized by their effectiveness under relatively mild operating conditions that achieve high selectivity over the desired acetic acid in the carbonylation of methanol.

However, both iridium and rhodium are rare, precious metals and rhodium in particular is difficult to obtain because this metal is increasingly used in petrochemical catalysis and in catalytic muffler applications. Moreover, it is clear from the latest publications that much dimethyl ether is formed during the carbonylation of methanol, catalyzed with rho-35 dium, in pure methanol as a solvent, as reported by Matsumato et al. 7906415 • 9 · -3- 20879 / Vk / iv /

Bull. Chem. Soc. Japan, 50, 2337 (1977) »

One of the objects of the invention is to use certain ruthenium containing catalysts that are effective in the selective carbonylation of aliphatic alcohols to the corresponding aliphatic carboxylic acids with an additional carbon atom per molecule. The process of the invention is primarily directed to the synthesis of acetic acid from methanol. The ruthenium-based process gives a selectivity to acetic acid of more than 90 mol%, a high yield of liquid and a suppression of the formation of gaseous by-product. In particular, preferably those ruthenium catalysts are used according to the process which minimizes the formation of carbon dioxide by the displacement of the water gas and of methane by the methane formation as shown in equations 2 and 3. Other products, in particular the formation of methyl acetate as shown in reaction equation 4 are in equilibrium 15 and are controlled so that this ultimately results in an acetic acid yield. CO + H2 O - * CO2 + H2 2.

CO + 3H2-> CH ^ + H20 3.

CHgCOOH + CH30H ^ CH3C00CH3 + H20 4.

In order to obtain the desired selectivity greater than 90% acetic acid and the yields via the ruthenium catalyzed carbonylation process, it has been found that preferably all methanol carbonylations are conducted in such a way that the ruthenium catalyst / methanol / acetic acid reaction mixtures do not contact cores with iron or steel-containing walls and fittings commonly used in the construction of pressurized reactors. Therefore, the examples listed below have been carried out in glass-coated or silver-coated equipment.

It has also been found necessary with ruthenium catalysts to add an iodide or bromide-containing promoter to the reaction mixture before carbonylation takes place in order to achieve the desired rapid and selective acetic acid formation. The preferred structure for the compositions of these catalyst components are explained in more detail below.

In general, according to the invention, carboxylic acids and the ester-7906415, i-* -A-20879 / Vk / iv derivatives are prepared from alcohol reactants and their ester derivatives by contacting the reactants with carbon dioxide in the presence of one or heating more ruthenium-containing catalyst precursors and a halogen-containing promoter and the reaction mixture under superatmospheric pressure until the desired yield of acidic product is obtained.

More specifically, according to the process of the invention, aliphatic carboxylic acids and the ester derivatives with two or more carbon atoms are prepared from aliphatic alcohol reactants with 1-12 carbon atoms or esters thereof by a process characterized by *.

A) Contacting the aliphatic alcohol and / or ester with at least a catalytic amount of ruthenium-containing compound in the presence of a halogen-containing promoter where the halogen is bromine or iodine, b) the reaction mixture under an elevated pressure of 3A atmosphere or higher is heated with sufficient carbon monoxide to satisfy the stoichiometry of the desired aliphatic acid product, until sufficient formation of the desired acids and esters is accomplished, and c) the acids and esters are separated from the reaction mixture.

To further explain this method and to gain a better understanding of. the process used follows a further explanation of the various parameters below.

a) The catalyst composition.

The catalyst which has been found to be suitable in the practice of the process according to the invention mainly contains a ruthenium compound and a halogen compound wherein halogen is bromine or iodine. A large number of ruthenium compounds can be used as a catalyst. It is generally believed that, without limiting the invention thereto, the catalytically active ruthenium compounds of the invention are present in the alcohol carbonylation in the form of a coordination complex of ruthenium and halogen.

These coordination compounds generally include carbon monoxide ligands, and ruthenium complexes such as RuiCO 2 are separated from typical product mixtures, as further illustrated in Examples XIV and XV.

Other units may also be present if desired and ruthenium may be added to the reaction zone as a coordination complex of ruthenium with halogen ligands or may be supplied as separate components using the ruthenium compound and a halogen compound.

7906415

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Specific examples of the ruthenium compounds suitable in the process of the invention include iodine-containing ruthenium salts such as ruthenium (III) triiodide, ruthenium (II) diiodide and tricarbonyl ruthenium (II) diiodide. On the other hand, the carbonylation of typical n-alcohols can be accomplished by adding ruthenium to the reaction mixture in an oxide form, such as, for example, in ruthenium (IV) dioxide hydrate, anhydrous ruthenium (IV) dioxide and ruthenium (VIII) tetraoxide. These substances can also be added to the reaction zone as the salts of a mineral acid such as ruthenium (III) chloride hydrate, ruthenium (III) bromide, anhydrous ruthenium (III) chloride and ruthenium nitrate or as the salt of a suitable organic carboxylic acid. Examples include ruthenium (III) acetate, ruthenium (III) propionate, ruthenium hexafluoroacetylacetonate, ruthenium (III) trifluoroacetate, ruthenium octanoate, ruthenium naphthenate, ruthenium valerate and ruthenium (III) acetylacetonate. Ruthenium can further also be fed to the reaction zone 15 as a carbonyl or hydrocarbonyl derivative. Suitable examples of this include triruthenium dodecacarbonyl, hydrocarbonyl compounds such as HgRu (iCO) ^ and H ^ Ru ^ (CO) ^ 2 and substituted carbonyl compounds such as tricarbonyl ruthenium (II) chloride dimer, RufCOJ ^ Clg.

Another important class of catalyst precursors includes compounds in which ruthenium is fed to the reaction zone as one or more of the forms such as oxide, salt or carbonyl derivative in combination with one or more tertiary donor ligands of group VB-. group VB are nitrogen, phosphorus, arsenic and antimony. These trivalent oxidation state elements, especially tertiary phosphorus and nitrogen, may be bonded to one or more of the following radicals, alkyl, cycloalkyl, aryl, substituted aryl, aryloxide, alkoxide, and mixed alkaryl. up to 12 carbon atoms or may be part of a heterocyclic ring system or mixtures thereof. Examples of suitable ligands suitable for use in the process of the invention include: triphenylphosphine, tri-n-butylphosphine, triphenylphosphite, triethylphosphite, trimethylphosphite, trimethylphosphine, tri-p-methoxyphenylphosphine, triethylphosphine, trimethylarsine, triethylarsine tri-p-tolylphosphine, tricyclohexylphosphine, dimethylphenylphosphine, trioctylphosphine, tri-o-tolylphosphine, 1,2-bis (diphenylphosphine) ethane, triphenylstibine, trimethylamine, triethylamine, tri-propyridine-triine 2,2,2-dipyridyl, 1,10-phenanthroline, 7906415-6-2079 / Vk / iv quinoline, N, N'-dimethyipiperazine, 1,8-bis (dimethylamino) naphthalene and N, N-dimethylaniline.

One or more of this ruthenium-tertiary group of VB donor ligands in certain combinations may first be formed before being fed to the reaction zone, for example the tris (triphenylphosphine) ruthenium (II) chloride and tricarbonylbis (triphenylphosphine) ruthenium or, alternatively, the complexes in be formed in situ. The operation of each class of the ruthenium catalyst precursors is further illustrated by the examples set forth below, especially Examples I-XI.

As mentioned earlier, it is possible that the halogen component of the catalyst system is combined with ruthenium, for example as ruthenium (III) iodide and Ru (CO2) 3 · J2, although it is generally preferred to use an excess of halogen in the catalyst system to be present as a promoter. By excess is meant an amount of halogen greater than 3 atoms of halogen per atom of ruthenium in the catalyst system.

This catalyst system promoter may consist of halogen and / or a halogen compound. Suitable halogen compounds include hydrogen halides such as hydrogen iodide and hydrous hydroiodic acid, alkyl and aryl halides of 4-12 carbon atoms such as methyl iodide, ethyl iodide, 1-iodopropane, 2-iodo-20-butane, 1-iodobutane, ethyl bromide, iodobenzene and benzyl iodide such as acyl iodides such as acetyl. As suitable halogen co-reactants, the alkali and alkaline earth alkene halides, ammonium and phosphonium halides can also be used. Suitable examples include sodium iodide, cesium iodide, potassium iodide, tetramethylaromonium iodide, tetrabutylphosphonium iodide and potassium bromide. Preferably, iodide-containing promoters are co-reactants for the ruthenium catalyzed carbonylation reaction of the invention, especially alkyl iodide having 1-12 carbon atoms, the alkyl radical corresponding to the number of carbon atoms and the structure to the alkyl radical of the aliphatic alcohol reactant.

B) The composition of the alcohol.

Suitable alcohol reactants for the ruthenium catalyzed carbonylation of the invention include saturated aliphatic hydrocarbyl alcohols, ROH and its ester derivatives. The saturated hydrocarbyl radicals (R) can include straight-chain and cyclic saturated radicals having 1-12 carbon atoms. Generally, these radicals contain one carbon 790 6 4 1 5-7 20879 / Vk / iv * ft.

atom less than the desired acid. Examples of alcohols that can be carbonated to the corresponding aliphatic carboxylic acids by the process of the invention include methanol, ethanol, n-propanol, iso-propenol, the butanols, pentanols, heptanols, including n-heptanol, 5-decanols , dodecanols, as well as cyclohexanol and cyclopentanols.

Suitable reactants for the carbonylation process of the invention are the corresponding aliphatic carboxylic acid esters of the alcohols mentioned above. These esters generally have formula R '- (sO) -OR, where R and R * are saturated hydrocarbyl radicals that are straight, branched or cyclic and contain 1-12 carbon atoms. Suitable examples of these esters are methyl acetate, ethyl acetate, propyl acetate, propyl propionate, ethyl propionate, pentyl acetate and the like.

The alcohol reactants may also be mixtures of one or more aliphatic alcohol reactants in combination with one or more aliphatic carbonic acid esters. This is indicated, for example, in Example XXVII below, using a mixture of methanol and methyl acetate.

The preferred starting mixture for the carbonylation are alcohols with 1-12 carbon atoms. Methanol is particularly preferably used here.

C) The composition of the solvent.

As described above, the carbonylation to obtain the desired carboxylic acids is generally carried out by contacting the above reactant component, preferably in an alcohol, with gaseous carbon monoxide in a liquid phase containing the catalyst system, in particular the ruthenium-containing component and a halogen-containing promoter such as methyl iodide. Generally, the liquid phase for the carbonylation consists essentially of the alcohol supplied, and preferably the ruthenium-iodide catalyst combinations are first dissolved in the alcohol reactant for the carbonylation. In the subsequent carbonylation, the ruthenium catalyst combinations are then first dissolved in the aliphatic carboxylic acid products. Examples I-III give a further elaboration of this in which the methanol carbonylation to acetic acid is effected.

In a second embodiment of this process, as the liquid phase components with the ruthenium catalyst herein, significant amounts of the carboxylic acid ester, the carboxylic acid product, for the carbonylation, are the 7906415% by weight 20879 / Vk / iv aqueous co. product and / or inert solvent. The first addition of the different amounts of alcohol, acid, acid ester and water can change considerably as can the control of the distribution of the final product. Examples illustrating this relate to the liquid mixing feed supplied from an aliphatic alcohol, an acid with a carbon atom more than the alcohol, and the ester of the acid and alcohol. Example XXVII illustrates this in which the liquid consists of methanol, methyl acetate and methyl iodide and acetic acid as the major fraction. Example XXVIII illustrates the use of the liquid feed consisting of methanol, water and acetic acid.

The ruthenium-catalyzed alcohol carbonylation can also be carried out in the presence of one or more inert diluents. Preferably, these diluents should have a boiling point higher than that of the acid and / or ester obtained. Suitable inert diluents which can be used to promote the solubility of the ruthenium iodide catalysts and as adjuvants in the desired carbonylation include aromatic hydrocarbons of 6-20 carbon atoms, higher boiling organic carboxylic acids and the esters composed of the above acids in combination with the starting material that is subjected to the carbonylation. Examples XXVI and XXIX give a further elaboration of this in which xylene and toluene are added as an inert diluent during the carbonylation of methanol to acetic acid. Quaternary ammonium and phosphonium salts are also suitable as inert diluents in this process, especially the low boiling salts such as tetrabutylphosphonium acetate.

D) The catalyst concentration.

The amount of ruthenium catalyst used in the process of the invention is not critical and can vary within wide limits.

In general, it is desirable to carry out the carbonylation in the presence of a catalytically effective amount of the active ruthenium compound giving the desired acid and / or ester products in a reasonable yield. The reaction takes place when a small amount of about 6 1 x 10 wt% is used and even a smaller amount of ruthenium based on the total weight of the reaction mixture. The upper limit for the concentration is determined by various factors including the catalyst cost, the carbon monoxide partial pressure, the processing temperature, and the selection of the diluent and reactant 79 0 6 4 1 5 -9- 20879 / Vk / iv. A concentration of -5.

the ruthenium catalyst from about 1 x 10 to about 10 wt% ruthenium, based on the total weight of the reaction mixture, is generally desirable in the practice of the process of the invention.

E) The temperature at which the method according to the invention is carried out.

The temperature may generally vary in the synthesis of the ester depending on other experimental factors including the choice of the starting alcohol, the pressure and the concentration, and in particular the choice of the catalyst. When ruthenium is again used as the active metal, it is preferable to work at a temperature of from 30 ° C to 350 ° C when a superatmospheric pressure of syngas is applied. A preferred temperature is at 170-240 ° C when an aliphatic carboxylic acid and ester derivative thereof is prepared as the main product. Table C shows the importance of the preferred range.

f) Press.

A superatmospheric pressure of 34 atmospheres or higher results in a significant yield of desired carboxylic acid and its esters by using the process of the invention. A preferred range for solutions of ruthenium (UI Jacetylacetonate in methanol ranges from 34 to 340 atmospheres, although pressures above 340 atmospheres also yield a suitable yield of the desired ester. Table C clearly indicates the impact of the limited Range of Pressure The pressures referred to are the total pressure generated by all reactants, although this pressure can be attributed almost entirely to carbon monoxide in the examples.

g) Gas composition.

As far as can be determined, the best selectivity and yield of carboxylic acid / ester can be obtained within a reasonable reaction time using a mainly carbon monoxide gas atmosphere.

With each synthesis, the amount of carbon monoxide present in the reaction mixture is a variable, but sufficient carbon monoxide must be present to satisfy the stoichiometric equation shown in Reaction Equation 1.

7906415 -10- 20879 / Uk / iv

In particular in a continuous process, but also in a non-continuous operation, carbon monoxide can be used together with up to 50% by volume of one or more other gases. These other gases may include one or more inert gases such as nitrogen, argon, neon and the like or they may include gases which may or may not participate in the CO carbonylation reaction under the indicated conditions such as carbon dioxide, hydrogen, hydrocarbons such as methane, ethane, propane and the like, ethers such as dimethyl ether, methyl ethyl ether and diethyl ether, alcohols such as methanol and acid esters such as methyl acetate.

H) Product distribution.

As far as can be determined, without limiting the invention thereto, the use of the ruthenium catalyst in the one-step carbonylation process which results in the formation of two kinds of primary products. The first type of primary products is the carboxylic acid, preferably aliphatic carboxylic acids with two or more carbon atoms. The second type of primary products is an ester derivative of these carboxylic acids. When methanol is used as an alcoholic reactant, the main product is acetic acid and methyl acetate. Smaller amounts of by-products that can be determined in the liquid product include small amounts of water, ethyl acetate, propyl acetate, ethanol and dimethyl ether. Carbon dioxide, methane and dimethyl ether can also be determined in the waste gas together with the unreacted carbon monoxide.

i) Method of implementation.

The method according to the invention can be effected continuously, semi-continuously or non-continuously. During the carbonylation of a specific alcohol reactant to be mentioned, it is desirable to minimize the formation of gaseous by-products, in particular the formation of CO2 and methane, by achieving a certain equilibrium between the water gas shift and the methanation as shown in the Equations 2 and 3. It has been found hereby that when using ruthenium catalysts, gaseous by-product formation can be minimized by avoiding contact between the ruthenium-containing liquid reaction mixture and iron or steel-containing metal surfaces during carbonylation. . It is of particular importance here that the metal surface, such as a surface made of stainless steel 316, from which reactors operating under high pressure are usually made, is avoided. One possibility by which this contact can be minimized is when carbonylation of the alcohol is carried out in a glass-lined reactor. A second alternative method is to coat the carbonylation reactor with other inert materials such as using a silver-coated reactor before the alcohol-carbonyl 5 ring takes place. Other alternatives include the use of titanium-coated pressure reactors, tantalum-coated reactors, and reactors consisting of a Hastelloy alloy or copper-nickel alloy. Example XXXII indicates the necessity of using a lined pressure reactor during ruthenium catalyzed acetic acid synthesis. The ruthenium catalyst of the present invention may first be fed to the reaction zone which is batchwise or may be continuously or intermittently supplied to such zone during the course of the synthesis reaction. The operating conditions can be adjusted to optimize the formation of the desired acid and / or the desired ester and the material to be recovered in a manner known to those skilled in the art to which distillation, fractionation, extraction and the like may be employed. A fraction rich in the ruthenium catalyst component can then be recycled to the reaction zone if desired and additional acid and / or ester products obtained by the CO carbonylation. Example XXXI illustrates the suitability of the recirculation.

, j) Analyzes to be performed.

The product obtained by the carbonylation can be determined by performing one of the analytical operations listed below, in particular a gas-liquid phase chromatography (glc), infrared (ir), mass spectrometry, nuclear magnetic resonance (nmr ) and elemental analysis or by a combination of these techniques. The analyzes are usually expressed in percentages by weight, the temperatures in ° C and the pressures in atmosphere.

The invention is further illustrated by the following non-limiting examples.

Example I

To a nitrogen purged sample of 25 g of methanol (0.78 mol) and 5.0 g (35 mmol) of methyl iodide in a glass-lined reactor, on which reactor means are applied to provide higher pressure, heating, cooling and stirrers were added 0.954 g of ruthenium dioxide 7906415-12-2079 / Vk / iv hydrate (5 mmol). The mixture was stirred to dissolve most of the solid to give a dark, almost black liquid. The reactor was closed, rinsed with CO, pressurized to 136 atmospheres with CO and then heated to a temperature of 220 ° C with shaking for 3 hours. The maximum pressure was 292.5 atmospheres, the gas absorption being 102 atmospheres. After cooling, a sample was taken while releasing the pressure of the reactor and 45 g of a clear, deep red liquid product were obtained. The liquid samples were analyzed by gas chromatography and according to a Karl-Fischer titration.

The analytical data of the liquid product, after the gas-liquid chromatography using a column of 182.9 x 0.317 cm consisting of 60/80 mesh Poropak-QS, at a temperature of 140-280 ° C are: methanol conversion> 98% acetic acid concentration 96.9 wt% 15 methyl acetate concentration 0.8 wt% water 2.1 wt% mixture 0.2 wt%

The analysis of the gas samples on a 348 cm x 3.2 mm column consisting of 5A molecular sieves at a temperature of 25-99 ° C, in combination with a 182.9 x 0.317 cm column of Porapak-Q (at a temperature of 70-240 ° C) gave the following results: 96.6% CO, 0.5% CO2 and 1.1% CH2.

The acetic acid and methyl acetate fractions could be recovered from the crude liquid product by fractional distillation at atmospheric pressure. The remaining ruthenium catalyst could be recycled for reuse in the next carbonylation starting from a fresh methanol feed.

Example II

To a nitrogen purged sample of methanol in an amount of 20 g (0.63 mmol) and 3.97 g of methyl iodide (28 mmol) in a glass lined reactor was added 0.608 g of ruthenium iodide. The mixture was stirred to dissolve most of the solid to give a dark, almost black liquid. The reactor was closed, rinsed with CO, pressurized to 136 atmospheres with CO, then heated to 220 ° C for 18 hours with shaking. The maximum pressure was 253.5 / 7906415 -13-20879 / Vk / iv atmosphere with a gas uptake of 100.4 atmosphere. After cooling, a gas sample was taken while decreasing the pressure on the reactor and 35.1 g of a clear, deep red liquid product were obtained. The samples were analyzed by gas-liquid chromatography and by Karl-Fischer titration.

The analysis data regarding the liquid product obtained via the glc determination were: methanol conversion> 98% acetic acid concentration 97.3 wt% methyl acetate concentration 1.4 wt% ethyl acetate concentration / 0.7 wt% water 0.2 wt% mixture 0.5 wt%

The analysis of the gas gave the following results: 93.2% CO, 5.5% CO2 and 1.3% CH2

The acetic acid fraction and the methyl acetate could be obtained from the iodide-containing liquid product by fractional distillation at atmospheric pressure. The remaining ruthenium catalyst could be recycled by subsequent carbonylation using fresh methanol feed.

Example III

To a nitrogen purged sample of 25 g (0.78 mol) of methanol and 5.0 g (35 mmol) of methyl iodide in a glass-lined reactor, 0.477 g of ruthenium (IV) dioxide hydrate (2.5 mmol) was added. The mixture was stirred to dissolve most of the solid, then the reactor was closed, rinsed with CO and pressured to 34 atmospheres with CO. The mixture was heated to 220 ° C with shaking and at this temperature the pressure was raised to 272 atmospheres by adding CO. The pressure was maintained at 272 atmospheres using a pressure regulator connected to a CO2 feed tank. After 5 hours, the reactor was cooled quickly and a sample of bicycle off-gas was taken while releasing the pressure of the reactor, and 39.1 g of a clear yellow liquid was obtained. No solid fraction was present.

The liquid sample was analyzed by gas-liquid chromatography and according to a Karl-Fischer titration.

The data concerning the liquid product are: 35 79 0 6 4 1 5, "β *" -14-20879 / Vk / iv raethanol concentration 0.3 wt% acetic acid concentration 73.4 wt% methyl acetate concentration 16.4 wt. % ethyl acetate concentration site 2.3 wt% 5 water concentration 3.7 wt%

A similar product distribution is obtained when the above experiment was repeated using 3.8 g (35 mmol) ethyl bromide instead of methyl iodide as a halogen promoter and 23 g ethanol as an alcohol reactant. When the carbonylation step was accomplished, liquid product was obtained and analyzed and found to contain 25% propionic acid plus propionate esters.

Examples IV-XI

The carbonylation of methanol to acetic acid was carried out using the method as described in Example II using different soluble ruthenium catalysts but under comparable conditions in terms of temperature, pressure and initial methanol-ruthenium ratio. As will be apparent from the data summarized in Table A, a number of ruthenium oxides, salts and complexes in combination with Group VB tertiary donor ligands are effective in the conversion of methanol to acetic acid and / or methyl acetate. The water concentration in the liquid product was determined according to the Karl-Fischer titration while the other components were analyzed by a gas-liquid chromatographic determination.

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Table A

pre-catalyst solution / Ru] maximum image medium1 ^ (wt%) rature pressure (° C) (atmosphere) ^ 5 IV Bu (acac) 3-Hel ^ MeOH 0.41 220 277.3 V RuCl3- MeI MeOH 0.42 220.282.4 VI Ru02-Mel MeOH 0.42 220 246.6 VII Ru3 (C0) l2-MeI MeOH 0.42 220 270.5 VIII RuCl2 (PPh3) 3-MeI MeOH 0.40 220 292.6 10 IX _ Ru (acac-Fg) 3-MeI ^ MeOH 0.41 220 284.0 X (iu (C0) 3Cl272-MeI MeOH 0.42 220 302.8 XI Rul3-Mel MeOH 0.39 220 262.0

pre-concentration (wt%) in liquid product 15 image water HOAc MeOAc MeOH

IV 3.48 82.1 10.9 V 4.12 75.7 13.3 VI 1.54 86.5 9.0 VII 4.67 68.1 21.4 0.5 20 VIII 15.1 15, 2 33.7 9.3 IX 3.15 72.0 19.7 0.3 X 1.80 81.1 '12.9 0.1 XI <0.1 97.3 1.4 25 ^ supplied 50 g of methanol (1.56 mol), 10 g (71 mmol) of methyl iodide and 2.5 mmol of ruthenium 0 initial pressure 136 atmospheres D ruthenium (III) acetylacetonate, ruthenium (IIHExafluoroacetylacetonate).

30 7906415, ^. % c · .. ..

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Examples XII-XXIII

In these examples, the method as described in Example I was used, in which the influence of varying the processing temperature, pressure and molar ratio was investigated. The methanol carbonylation to acetic acid and methyl acetate are the standard reactions using ruthenium dioxide, ruthenium (III) chloride and ruthenium (III) acetylacetonate as catalyst pre-cursors. The results obtained herein are summarized in Tables B and C. From these data it is clear that the methanol carbonylation to acetic acid can be accomplished under a wide range of conditions such as: 1) an initial molar ratio of methanol to ruthenium to at least 3 at least 10 or higher, 2) the operating temperature from 30 to 240 ° C, 3) super-atmospheric pressure of 34 atmospheres or higher.

When the solution of the crude product obtained after the carbonylation as in Examples XIV and XV is left to stand for 1 or more days, significant amounts of 0.1 to 1.2 g of a yellow crystalline solid are precipitated. This solid was separated by filtration, washed with diethyl ether and dried under reduced pressure. The resulting substances were examined in more detail by spectroscopic determination and elemental analysis and were found to contain tricarbonyl-ruthenium (II) iodide, RuiCO 2 Jg. The data from the elemental analysis are:

Ru (%) C (%) J (%) calculated for RuJgC ^ O ^ 23.0 8.20 57.8 25 found 23.8 7.198 56.7

The crude liquid product spectrum indicates the presence of these and similar ruthenium carbonyl compounds.

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Table B

pre-mix_ time concentration (wt%) in image precursor Ru MeJ MeOH (hours) liquid product

(mmol) (mmol) (mol) HgO HOAc MeOAc MeOH

5 _____ XII RuC13xH20 1.25 71 1.56 6 7.6 43.8 36.3 0.9 XIII RuC13xH20 5.0 71 1.56 6 3.8 70.8 20.2 0.9 XIV RuC13xH20 10, 0 71 1.56 6 3.5 79.1 13.4 1.3 XV RuOjjXJ ^ O 10.0 35 0.78 1.5 8.0 47.4 30.0 0.7 10 XVI Ru (acac) 3 1.25 71 0.78 6 12.5 24.8 43.0 2.6 XVII Ru (acac) 3 1.25 4.4 0.78 6 13.5 1.0 28.7 46.8

Table C

pre-precursor taupe pressure concentration (wt%) in liquid product

15 image rature atmosp- HgO HOAc MeOAc MeOH

(° C) feer ____________— - XVIII Ru (acac) 39 240 285.8 4.6 86.0 4.8 XIX Ru (acac) 3 ') 170 251.7 8.7 12.9 33.1. 5.6 XX Ru (acac) 3 0 30 204.1 ^ 0.2 4.7 - 95.0 20 XXI RuC13xH2o9 220 336.8 2.5 83.2 9.5 XXII RuC ^ xHgO *) 220 173, 5 39.6 5.0 15.5 17.9 XXIII RuC13xH202) 150 34.03) 19.8 <5.0 28.8 11.6 9 supply of 50 g of methanol (1.56 mol), 10 g of methyl iodide (71mmol) and 2.5mmol of ruthenium (III) acetylacetonate 9 feed 10.0mmol of ruthenium (III) chloride hydrate 5 experiment at constant pressure.

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Example XXIV

Following the procedure described in Example 1, 0.702 g (2.5 mmol) of ruthenium chloride hydrate, 50 g of methanol and 18.0 g of iodohydroic acid as 50% aqueous solution were fed to a glass-5. dress reactor. The reactor was flushed with CO, pressurized to 136 atmospheres with carbon monoxide and heated to a temperature of 220 ° C for 6 hours. After cooling, 79 g of a clear, yellow, liquid product were obtained which, after analysis, was found to have the following composition: acetic acid 54.1 wt.% Methyl acetate 16.0 wt.% Water 11.5 wt.% Methanol 0.5 wt. %

Example XXV

0.702 g of ruthenium chloride hydrate was added to a nitrogen purged sample of 50 g of methanol. The mixture was fed to a glass-lined reactor, frozen with carbonated ice, and 9.0 g of hydrogen iodide was injected from an ampule. The reactor was pressurized to 136 atmospheres with CO and heated to 220 ° C with shaking for 6 hours.

The maximum pressure was 285.8 atmospheres, a gas uptake taking place from 102 atmospheres. After cooling and depressurizing the reactor, 22.5 g of a bright yellow liquid product were recovered. There was no indication of a solid precipitate. The results of the analysis carried out with respect to the liquid product (gas-liquid chromatography) and using a Karl-Fischer titration were as follows: acetic acid 60.2 wt.% Methyl acetate 24.7 wt.% Water 4.8 wt% methanol 1.0 wt%

Example XXVI

The methanol carbonylation was carried out in the manner described in Example I, except that the feed mixture consisted of 1.25 g of ruthenium chloride hydrate (4.5 mmol), 24 g of methanol, 56 g of xylene and 10.56 g (71 mmol) sodium iodide. The reactor was pressurized with CO and heated to 220 ° C with shaking for 6 hours. Analysis of the liquid product indicated the presence of a significant amount of methyl acetate and 7906415 t * 1 C * -19-20879 / Vk / iv acetic acid.

Example XXVII

Following the procedure described in Example I, 1.25 g (4.5 mmol) ruthenium chloride hydrate, 5-24 g methanol, 10 g methyl iodide and 56 g <0.76 mol) methyl acetate were added in a glass-lined reactor. done. The reactor was pressurized with CO and heated to 220 ° C with shaking.

The analysis of the liquid product, carried out in an amount of 95 g, for which a gas-liquid chromatography was carried out, indicated an almost quantitative conversion of the methyl acetate and methanol-10 fractions to acetic acid. The acetic acid concentration and the crude product were greater than 90% by weight. An analysis of the off-gas indicated that it contained 96.7% CO, 1.2% CO2 and 1.2% CH2.

Example XXVIII

Following the procedure outlined in Example I, 1.25 g (4.5 mmol) of ruthenium chloride hydrate, 24 g of methanol, 10 g of methyl iodide together with 12.9 g of water and 43.1 were added to a glass-lined reactor. g (0.72 mol) acetic acid. The reactor was closed, rinsed with CO and pressurized to 136 atmospheres with carbon monoxide. The mixture was heated to 220 ° C with shaking and kept at a temperature of 220 ° C for 6 hours. After gas-liquid chromatography and a Karl-Fischer titration, the liquid product was found to have the following composition: acetic acid 72.9 wt.% Methyl acetate 5.0 wt.% Water 16.2 wt.% Methanol 0.3 wt. %

Example XXIX

Following the procedure of Example 1, 1.25 g (4.5 mmol) of ruthenium chloride hydrate, 24 g of methanol, 5 g of methyl iodide and 61 g of toluene were fed to a glass-lined reactor. The reactor was flushed with CO, pressurized to 136 atmospheres with carbon monoxide and heated to a temperature of 220 ° C for 6 hours. The gas uptake was 56.1 atmospheres. After cooling, a sample was taken from the exhaust gas while the pressure of the reactor was lowered and 101 g of a clear liquid product were obtained. No solid was present. The liquid was analyzed by gas-liquid chromatography and a Karl-Fischer titration was carried out, 7906415 V> -20-20879 / Vk / iv which showed that the product had the following composition: acetic acid 40.7 wt% methyl acetate 7 »1 wt% water 2.1 wt% methanol 0.3 wt% toluene as solvent 48.7 wt%.

The analysis of the waste gas indicated that it had the following composition: 95.1% CO, 2.0% CO2 and 2.0% Cl 2.

Example XXX

In this example, the carbonylation of n-heptanol was carried out using the procedure described in Example 1. The feed mixture consisted of 0.351 g (1.27 mmol) of ruthenium chloride hydrate, 5 g of methyl iodide and 90.6 g (0 .78 mol) n-heptanol. The glass-lined reactor was closed, purged with CO and pressurized with carbon monoxide. The reactor J5 was heated to 220 ° C with shaking, the gas intake being 51 atmospheres. After cooling and lowering the pressure of the reactor, a clear, pale yellow product was obtained, whereby after a gas-liquid chromatographic analysis, the product was found to contain 66.3% n-octanoic acid.

Example XXXI

To a glass-lined pressure vessel as indicated in Example I and equipped with pressurization, heating, cooling and stirring means, 2.77 g (10 mmol) of ruthenium chloride hydrate, 50 g (1.56 mol) of methanol, and 10 g of methyl iodide. The reactor was closed, rinsed with CO, pressurized with carbon monoxide to a pressure of 136 atmospheres, and heated to a temperature of 220 ° C for three hours. The gas uptake was about 68 atmospheres. After cooling and depressurizing the reactor, 86.5 g of a clear, yellow, liquid product were recovered. No solid residue or precipitate was present. Both methyl acetate and acetic acid are recovered as a clear water-like liquid by fractional distillation of the crude liquid product under a pressure of 1 atmosphere. The residual bottom fraction in the amount of 12.1 g was fed back into the reactor with the addition of 50 g of methanol and 10 g of methyl iodide, whereby the carbonylation was effected as indicated above. After performing a fractional distillation of the liquid product again, methyl acetate and acetic acid were recovered, after which the carbonylation of a third sample with 50 g of methanol 7906415. <'.

20879 / Vk / iv was performed in the same manner using 12 g of the residual ruthenium catalyst. Samples of the liquid product were analyzed from the three ruthenium catalyst operations by gas-liquid chromatography and Karl Fischer titration. 5 The data obtained hereby are summarized in table D.

Table D

cycle composition composition liquid product (concentration as% by weight)

H20 HOAc MeOAc EtOAc MeOH

10 _ 1 RuCl3xH20-MeI .3.47 79.1 13.4 0.7 1.3 2 recycling 7.5 61.9 24.1 1.3 0.8 3 recycling 1.73 76.2 16.4 3.0 0.1

Example XXXII

A glass-lined reactor described in Example I, equipped with pressurizing, heating, cooling and stirring means was charged with 0.966 g (2.5 mmol) ruthenium (III) acetylacetonate, 10 g (71 mmol) methyl iodide and 50 g (1.55 mol) of methanol. The mixture was stirred to dissolve any solid that formed and had a deep red color. The reactor was closed, rinsed with CO, pressurized to 136 atmospheres with CO, then heated to a temperature of 220 ° C overnight with shaking. The maximum gas pressure was 272 atmospheres and the gas uptake was 54.4 atmospheres. After cooling and depressurizing the reactor, 78 g of a clear yellow liquid product were recovered. No solid was present and the analysis of the liquid indicated that it contained 82.1 wt% acetic acid, 10.9 wt% methyl acetate and 3.4 wt% water with the methanol conversion being 98%.

To compare these data, a second experiment was conducted with a stainless steel reactor without glass cladding, adding the same mixture consisting of Ru (acac) ^ / MeOH / MeJ. The reactor was made of stainless steel 316. The reactor was again brought to a pressure of 136 atmospheres with carbon monoxide and heated to a temperature of 7906415 ί * τι »n * - 1, -22- 20879 / Vk / iv at 220 ° C. . However, after cooling and pressure reduction, the reactor was found to contain only 15.3 g of a green colored suspension. The analysis of the liquid by carrying out a gas-liquid chromatography and a Karl Fischer titration showed that water constituted the major part of the product since the product consisted of: 8.7 wt.% Acetic acid, 28.0 wt. % methyl acetate, 33.9% by weight water and 18.5% by weight unreacted methanol.

An analysis of the resulting off-gas confirmed the presence of large amounts of carbon dioxide and methane, since the off-gas 40.8% CO2, 14.2% CH2, 3.7% CO, 4.6% H2 and 9.6% MegO contained.

From the above examples and the considerations given herein, it appears that it has a number of advantages when using a method according to the invention. A relatively large group of ruthenium catalyst combinations can. are considered suitable in the preparation of acetic acid and its ester derivatives by reacting methanol in one step. It has further been found that using the ruthenium-catalyzed methanol carbonylation, it is possible to use within a wide range in terms of temperature, pressure and initial catalyst / reactant ratio.

- CONCLUSIONS - 7906415

Claims (10)

A process for preparing aliphatic carboxylic acids and their ester, derivatives thereof with 2 or more carbon atoms, starting from an aliphatic alcohol and / or ester reactant of the formula ROH and R'-C (= O) 0R, wherein R and R 'are saturated hydrocarbyl radicals having 1-12 carbon atoms, characterized in that a) the aliphatic alcohol and / or ester is contacted with at least a catalytic amount of ruthenium-containing compound in the presence of a halogen-containing promoter wherein the halogen is bromine or iodine, b) the reaction mixture is heated under an elevated pressure of 34 atmospheres or higher with sufficient carbon monoxide to satisfy the stoichiometry of the desired aliphatic acid product to form the desired acids sufficiently and esters have been accomplished and c) the acids and esters are separated from the reaction mixture. 2. Process according to claim 1, characterized in that the ruthenium-containing compound is selected from one or more of the ruthenium iodide salts, oxides of ruthenium, ruthenium salts of a mineral acid, ruthenium salts of an organic carboxylic acid and ruthenium carbonyl or hydrocarbonyl derivatives. 3. Process according to claim 2, characterized in that the ruthenium-containing compound is selected from ruthenium (III) triiodide, tricarbonyl ruthenium (II) iodide, ruthenium (IV) dioxide hydrate, anhydrous ruthenium (IV) chlorochloride. ride, ruthenium (VIII) tetraoxide, ruthenium (III) chloride hydrate, ruthenium acetate, ruthenium propionate, ruthenium (III) hexafluoroacetylacetonate, ruthenium (Ill) acetylacetonate, triruthenium dodecacarbonyl and tricarbonyl chloride. 4. Process according to claims 1-3, characterized in that the halogen-containing promoter is hydrogen iodide or an alkyl halide with 1-12 carbon atoms. 5. Process according to claims 1-4, characterized in that methanol is used as the aliphatic alcohol. 6. Process according to claim 4, characterized in that the alkyl halide promoter contains an alkyl radical with the same number of carbon atoms and structure as the alkyl radical of the aliphatic alcohol * Process according to claims 1-6, characterized in that the aliphatic carboxylic acids are prepared in the presence of water. 8. Process according to claims 1-7, characterized in that the alcohol reactant is carbonylated in the presence of one or more aliphatic carboxylic acids. Process according to claims 1-8, characterized in that the alcohol and / or ester reactant are carbonylated in the presence of an inert organic diluent. 10 7906415