DE19706876A1 - Process for the preparation of carboxylic acids or their esters by carbonylation of olefins - Google Patents

Abstract

The invention relates to a method for producing carboxylic acids or their esters from olefins and carbon monoxide in the presence of water or alcohols at temperatures of between 100 and 270 DEG C and pressure of between 30 and 100 bar. Said method is characterized in that as halogen-free catalyst system it uses a mixture of a) nickel or a nickel compound; b) at least one of the metals of a group including chromium, molybdenum, wolfram, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver and gold, or a compound of these metals; c) at least one non-metallic compound from the group of tertiary or quaternary nitrogen, phosphorus or arsenic compounds and nitrogen-containing heterocyclic compounds.

Description

The present invention relates to a method for manufacturing of carboxylic acids or their esters by reacting an olefin with carbon monoxide in the presence of water or alcohol and a halogen-free catalyst system, a mixture of nickel or a nickel compound, at least one noble metal or its connection and a non-metallic nitrogen, Ar sen or phosphorus compound, at a pressure of 30 to 100 bar and 100 to 270 ° C.

Weissermel et al. describe in industrial organic chemistry, 1978, 2nd edition, Verlag Chemie, p. 132 the carbonylation of Olefins by the Reppe process, for example the production of propionic acid from ethylene, carbon monoxide and water in counter were from catalysts. Nickel propionate is used as a catalyst set that under reaction conditions to nickel carbonyl implements. A high conversion of ethylene is only possible at high pressures (200-240 bar). These reaction conditions require one high technical effort when building suitable reactors and - due to the corrosiveness of the product under the reaction conditions - special and expensive materials.

GB-A 1 063 617 teaches the carbonylation of olefins Nickel and cobalt catalysts in the presence of boric acid. Also this requires high pressures and temperatures.

Carbonylations of olefins can be carried out with noble metal catalysts at pressures of approx. 100 bar. This is how she teaches EP-A 1 495 547 catalysts consisting of a palladium source and bidentate phosphine ligands exist. Such catalysts who but often after a short reaction time by deposition metallic palladium deactivated; in particular are the one put phosphine ligands under the desired reaction conditions not thermostable.

DE-A 44 24 710 describes the carbonylation of olefins a mixture of nickel or a nickel compound and one Noble metal or a noble metal compound as a catalyst system. However, the method described is in terms of Selectivity and activity regarding the pro to be manufactured  Products, especially at pressures below 100 bar, have not yet been cleared digend.

It was therefore the task of a process for carbony tion of olefins to provide the above Avoids disadvantages and in terms of its selectivity and Activity, at pressures up to 100 bar, is improved.

Accordingly, a new and improved process for the production of carboxylic acids or their esters from olefins and carbon monoxide in the presence of water or alcohols and a halogen-free catalyst system at temperatures from 100 to 270 ° C and pressures from 30 to 100 bar, preferably 30 to 80 bar , characterized in that a mixture of

• a) nickel or a nickel compound,
• b) at least one of the metals from the group chromium, molybdenum, Tungsten, rhenium, ruthenium, osmium, rhodium, iridium, Palladium, platinum, silver, gold or a combination of these Metals and
• c) at least one non-metallic compound from the group the tertiary or quaternary nitrogen, phosphorus or Ar sen compounds and the nitrogen-containing heterocyclic Connections

The activity and the Selectivity compared to that described in DE-A 44 24 710 Catalyst system, especially at low pressures up to 100 bar, can be significantly improved. It is also in the The catalyst system used according to the invention also in low water concentrations of 0.5 to 5 moles of water per mole Olefin so active that it enables the production of carboxylic acids which already has a water content of Have less than 1%, whereby the workup of the reaction pro product is significantly simplified.

The following reaction equation illustrates the process according to the invention using the example of the conversion of ethylene to propionic acid:

Coming as starting materials for the process according to the invention aliphatic and cycloaliphatic alkenes with preferably 2 to 20, particularly preferably 2 to 7 carbon atoms. Examples are ethylene, propylene, isobutene, 1-butene, 2-butene and the isomers of pentene and hexene and cyclohexene nen, of which ethylene is preferred.

These olefins are used to make carboxylic acids with water or for the production of carboxylic acid esters with alcohols puts. These alcohols include aliphatic and cycloaliphatic Compounds with preferably 1 to 20 carbon atoms, especially preferably with 1 to 6 carbon atoms, such as methanol, ethanol, n-propanol, iso-propanol, tert-butanol, stearyl alcohol, diols such as ethylene glycol, 1,2-propanediol and 1,6-hexanediol and cyclo hexanol. If diols are converted, depending on the selected stoichiometric ratios of mono- and diesters are obtained which, for the production of diesters, the diol and the olefin in a molar ratio of about 1: 2 and to produce the Monoesters are used in excess of the diol.

The starting compounds mentioned are reversed with carbon monoxide sets, this in pure form or diluted with inert Gases such as nitrogen or argon can be used.

The molar ratios of the starting compounds olefin and Water or alcohol can vary widely, however is usually at least an equimolar amount of water or Alcohol used. In the manufacture of carboxylic acids 0.5 to 10 mol water per mol olefin, preferably 0.5 to 5 mol, be used.

The molar ratio of olefin to carbon monoxide can also be strong are varied, with a molar ratio of 5: 1 to 1: 5 mol Olefin per mole of carbon monoxide is preferred.

In the process of the invention, a mixture of is used as the halogen-free catalyst system

• a) nickel or a nickel compound,
• b) at least one of the metals from the group chromium, molybdenum, Tungsten, rhenium, ruthenium, osmium, rhodium, iridium, Palladium, platinum, silver, gold or a combination of these Metals and  
• c) at least one non-metallic compound from the group the tertiary or quaternary nitrogen, phosphorus or Ar sen compounds and the nitrogen-containing heterocyclic Connections.

To enable the active nickel compounds to form, compounds which are soluble therein, such as acetates, propionates, acetyl acetonates, hydroxides and carbonates or mixtures of these compounds, are expediently added to the reaction mixture. However, it is also possible to add Ni (CO) ₄ and nickel metal to the reaction mixture. It is particularly preferred to enter the nickel component in the form of salts of the carboxylic acids formed in the reaction.

At least one of the serves as the second catalyst component Metals or a combination of these metals from the group chromium, Molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, Palladium, platinum, silver, gold, of which rhodium and palladium preferred, ruthenium and platinum are particularly preferred. This Metals can, for example, as salts, as for above Nickel are specified, are introduced into the reaction solution, that is, as acetates, propionates, acetylacetonates, hydroxides or carbonates. Furthermore carbonyl compounds come in Be traditional, especially chrome hexacarbonyl, molybdenum hexacarbonyl, Tungsten hexacarbonyl, dirhenium decacarbonyl, triruthenium dodeca carbonyl, triosmium dodecacarbonyl and carbonyl compounds, the carry other ligands such as rhodium dicarbonylacetylacetonate or by donor ligands such as phosphines, arsines and nitrogen bases like olefins stabilized metal compounds. Platinum can too can be used as dibenzalacetone platinum. Ruthenium will come before preferably used as acetylacetonate. The metals are in the reaction mixture depending on the solubility ratios ge dissolves or suspends. The metals or compounds of these Metals of the catalyst component b) can also be organic or inorganic inert carriers, such as activated carbon, Graphite, alumina, zirconia and silica are used will.

At least one nonme serves as the third catalyst component metallic compound from the group of tertiary or quaternary Nitrogen, phosphorus or arsenic compounds and the nitrogen containing heterocyclic compounds.

Under quaternary nitrogen, phosphorus or arsenic compounds the quaternary ammonium, arsonium and phosphonium salts are ver stood.  

The third catalyst component c) preferably contains a compound of the general formula (I) as the quaternary nitrogen, arsenic or phosphorus compound

wherein E is nitrogen, phosphorus or arsenic, X ^{- is} a halogen-free anion such as a nitrate ion or a hydroxide ion, but particularly preferably an anion of the carboxylic acid formed in the reaction, and R ¹ , R ² , R ³ and R ^{4 are} aliphatic radicals such as alkyl groups which preferably carry 1 to 18 carbon atoms and are straight-chain or branched, particularly preferably C ₁ to C ₈ alkyl groups such as methyl, ethyl, n-propyl, n-butyl and octyl.

R ¹ , R ² , R ³ and R ⁴ can also represent a cycloaliphatic radical such as cyclopentyl or cyclohexyl, an aromatic radical such as phenyl or an aromatic radical substituted by alkyl groups such as tolyl or an araliphatic radical such as benzyl.

The third catalyst component c) preferably contains a compound of the general formula (II) as tertiary nitrogen, phosphorus or arsenic compound

wherein E, R ¹ , R ² and R ^{3 have} the meaning given above under formula I.

Suitable nitrogen-containing heterocyclic compounds are the third catalyst component c) pyridine, pyridine, quinoline, isoquinoline, pyrimidine, pyridazine, pyrazine, pyrazole, imidazole, thiazole and oxazole, preferably optionally substituted by C ₁ - to C ₄ -alkyl C ₁ - to C ₄ alkyl monosubstituted pyridine, quinoline, isoquinoline, pyrimidine, pyridazine, pyrazine, pyrazole, imidazole, thiazole and oxazole and their nitrogenated NC ₁ - to C ₄ -alkylated or N, NC ₁ - to C ₄ -dialkylated salts with halogen-free anions X-, where X has the meaning given above, preferably pyridine, N-methylpyridinium salts, imidazole and N, N-dimethylimidazolinium salts.

The molar ratio of the in the first component a) Catalyst system contained nickel for the second catalyst Component b) is 1: 1 to 100,000: 1, preferably 100: 1 up to 50,000: 1. The content of the reaction solution in the catalytic active metals of components a) and b) is 0.1 in total up to 5% by weight, calculated as metal. The molar ratio of nickel component a) to the third non-metallic catalyst Component c) is generally 2: 1 to 1:20, preferred at 1: 1 to 1: 10. The content of the reaction solution is not metallic catalyst component c) is 1 to 50 wt .-%.

The reaction can be carried out without or with a solvent will. In addition there are solvents such as acetone, ether, dioxane, Dimethoxyethane, tetraethylene glycol dimethyl ether, aprotic polar solvents such as N-methylpyrolidone and aromatic Hydrocarbons such as toluene. It is preferred that Implementation for the production of carboxylic acids in the 20 to 95 % By weight, preferably 50 to 80% by weight, aqueous carboxylic acid perform.

The preparation of the carboxylic acid esters according to the invention Ancestor is preferred in the respective alcohol, the 1 to Can contain 5 wt .-% water, carried out as a solvent.

In the manufacture of propionic acid, the use of aqueous propionic acid is preferred as the solvent.

The reaction is usually at 100 to 270 ° C, preferably 170 up to 250 ° C and pressures from 30 to 100 bar, preferably 30 to 80 bar, particularly preferably 40 to 60 bar.

The starting compounds olefin, water and the catalyst system can optionally in a solvent before the reaction be mixed in a reactor. You can then click on the Reaction temperature are heated, the reaction pressure by squeezing carbon monoxide or briefly when used chain olefins by injecting a mixture thereof Olefin and carbon monoxide is discontinued.  

As a rule, the reaction is complete after 0.5 to 3 hours. she can continuously or discontinuously in reactors such as boilers, Bubble columns, tubular reactors or circulation reactors who run the.

The reaction product is used to isolate the process products relaxed in a preferred embodiment. Then will Nickel carbonyl by passing gases such as air or stick substance removed from the liquid. Nickel carbonyl can be dated Inert gas separated and worked up to a nickel compound which can then be returned to the reaction. The liquid phase of the reaction discharge, which in addition to the process Contains product soluble or suspended catalyst worked up by distillation, the process product being given if necessary after a subsequent fine distillation, isolated becomes. The catalyst-containing distillation sump is in the Response returned. Likewise, before the Distillation separated catalyst components and as Low boilers or separated as a side stream of a distillation volatile catalyst components after appropriate work-up tion can be returned.

The inventive method allows the production of Process products in high space-time yield with high Selectivity.

Examples example 1 Discontinuous attempts to produce propionic acid

A solution of 2.13 g of basic nickel carbonate and 12 mg of ruthenium acetyl acetonate in a mixture of 90 g of propionic acid and 10 g of water was placed in a 300 ml autoclave with a magnetic stir bar. Then 20 g of a 40% aqueous solution of trabutylammonium hydroxide ([NBu ₄ ] OH) were added. A pre-pressure of 30 bar was then set with a gas mixture of 50% by volume of CO and 50% by volume of ethylene and the reaction solution was heated to 200.degree. After the reaction temperature had been reached, the final pressure was set at 60 bar and maintained by pressing the CO / ethene gas mixture for a quarter of an hour. After one hour, the mixture was cooled to room temperature, the pressure was released and the reaction product was examined by titrimetry and gas analysis. The result is summarized in Table 1.

Example 2

The test was carried out as described in Example 1. Instead of tetrabutylammonium hydroxide, however, 10 g of triethylamine (NEt ₃ ) were used. The result is shown in Table 1.

Example A

The experiment was as described in Example 1, but without Added a nitrogen compound. The result is summarized in Table 1.

Example B

The experiment was as described in Example 1, but without Ruthenium catalyst performed. The result is in Table 1 summarized.

Example C

The experiment was carried out as described in Example 1, but without a nickel catalyst. The result is summarized in Table 1.

In Examples 1 and 2 according to the invention, a Nickel, ruthenium and tetrabutylammonium hydroxide catalyst or triethylamine at 60 bar, significantly higher space-time yields and selectivities are achieved than in comparative experiment A. the two metallic catalyst components alone. The Comparative examples B and C illustrate that by adding Tetrabutylammonium hydroxide to one of the two catalyst metals no active catalyst system results. Experiments 1, 2, A and C show that the nitrogen components added mainly accelerate the carbonylation reaction, but far less the formation of the by-products ethane, propionaldehyde and diethyl ketone.

Example 3

In a 300 ml autoclave equipped with a gassing stirrer (1000 rpm) became a solution of 2.13 g basic nickel carbonate and 12 mg of ruthenium acetylacetonate in a mixture of 60 g Propionic acid and 40 g of a 40% aqueous tetrabylammoniumhy submitted hydroxide solution. Then it was made with a gas mixture 50 vol .-% CO and 50 vol .-% ethylene a pre-pressure of 30 bar provides and the reaction solution heated to 200 ° C. After reaching the reaction temperature was set at 75 bar and by continuously repressing the CO / ethene gas mixture kept constant. After two hours the temperature dropped to room temperature cooled, relaxed and the reaction discharge titrimetric and ga examined by analysis. The result is summarized in Table 2 composed.

Example D

A solution was found in the autoclave described in Example 3 from 2.13 g basic nickel carbonate and 12 mg ruthenium acetyl acetonate in a gas mixture of 50 vol.% CO and 50 vol.% Ethylene set a pre-pressure of 30 bar and the reaction solution heated to 200 ° C. After reaching the reaction temperature the final pressure of 75 bar was set and by continuous repressing the CO / ethene gas mixture kept constant. After two hours, the mixture was cooled to room temperature and the pressure was released and the reaction discharge under titrimetry and gas analysis is looking for. The result is summarized in Table 2.  

Example 4

The experiment was described as in Example 3, but with one Pressure of 55 bar carried out. The result is in Table 2 summarized.

Example 5

The experiment was described as in Example 3, but with 60 g Propionic acid, 25 g of a 40% aqueous tetrabylammonium hydro xid solution and 15 g water as a solvent and a pressure of 55 bar carried out. The result is summarized in Table 2 composed.

Example E

The test was carried out as described in Example D, but at a pressure of 55 bar. The result is summarized in Table 2.

Example 6

A solution of 2.13 g of basic nickel carbonate and 12 mg of ruthenium acetyl acetonate in a mixture of 80 g of propionic acid and 20 g of a 40% strength aqueous tetrabutylammonium hydroxide solution was placed in a 300 ml autoclave with a magnetic stir bar ([H ₂ O] = 12 G). A pre-pressure of 30 bar was then set with a gas mixture of 50% by volume CO and 50% by volume ethylene and the reaction solution was heated to 200.degree. After the reaction temperature had been reached, the final pressure was set at 100 bar and maintained by pressing the CO / ethene gas mixture for half an hour. After two hours, the mixture was cooled to room temperature and let down. 126 g of liquid reaction product were obtained. Gas chromatographic and titrimetric analysis gave the following composition, summarized in Table 3.

Example 7

A solution of 2.13 g of basic nickel carbonate and 12 mg of ruthenium acetyl acetonate in a mixture of 90 g of propionic acid and 10 g of water and 10 g of triethylamine was placed in a 300 ml autoclave with a magnetic stir bar. A pre-pressure of 30 bar was then set with a gas mixture of 50% by volume of CO and 50% by volume of ethylene and the reaction solution was heated to 200.degree. After the reaction temperature had been reached, the final pressure was set at 100 bar and maintained by pressing the CO / ethene gas mixture for half an hour. After two hours, the mixture was cooled to room temperature and let down. 134 g of liquid reaction product were obtained. The gas chromatographic and titrimetric analysis gave the following composition summarized in Table 3.

Examples 6 and 7 illustrate that the catalyst system consisting of a nickel compound, a ruthenium compound and a nitrogen-containing compound such as triethylamine or Tetrabutylammonium hydroxide even at very low water concentration has a high activity.

Claims (11)

1. A process for the preparation of carboxylic acids or their esters from olefins and carbon monoxide in the presence of water or alcohols at temperatures from 100 to 270 ° C and pressures from 30 to 100 bar, characterized in that a mixture of halogen-free catalyst system

• a) nickel or a nickel compound,
• b) at least one of the metals from the group chromium, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium palladium, platinum, silver, gold or a compound of these metals and
• c) at least one non-metallic compound from the group of tertiary or quaternary nitrogen, phosphorus or arsenic compounds and the nitrogen-containing heterocyclic compounds used.

2. Process for the preparation of carboxylic acids or their esters according to claim 1, characterized in that the components of the catalyst system in a molar ratio of a): b): c) from 1: 1: 0.5 to 100,000: 1: 200,000. 3. A process for the preparation of carboxylic acids or their esters according to claims 1 or 2, characterized in that the catalyst system is a quaternary compound of the general formula (I)
wherein E is nitrogen, phosphorus or arsenic, R ¹ , R ² , R ³ , R ^{4 is} an aliphatic, cycloaliphatic, araliphatic or aromatic radical and X is a halogen-free anion. 4. A process for the preparation of carboxylic acids or their esters according to claims 1 to 3, characterized in that the catalyst system is a tertiary compound of the general formula (II)
wherein E represents nitrogen, phosphorus or arsenic and R ¹ , R ² and R ^{3 represent} an aliphatic, cycloaliphatic, araliphatic or aromatic radical. 5. Process for the preparation of carboxylic acids or their esters according to claims 1 or 2, characterized in that the Content of the reaction solution in the non-metallic Ver bond c) is 1 to 50 wt .-%. 6. Process for the preparation of carboxylic acids or their esters according to claims 1 to 5, characterized in that the Reaction solution contains 0.5-10 mol water per mol olefin. 7. Process for the preparation of carboxylic acids or their esters according to claims 1 to 6, characterized in that the reaction at temperatures of 170 to 250 ° C and pressures from 40 to 60 bar. 8. Process for the preparation of carboxylic acids or their esters according to claims 1 to 7, characterized in that Carbon monoxide and the olefin in a molar ratio of 5: 1 to 1: 5 starts. 9. Process for the preparation of carboxylic acids or their esters according to claims 1 to 7, characterized in that uses ethylene as olefin. 10. Halogen-free catalyst system as in at least one of the Claims 1 to 4 defined, suitable for carrying out Process for the preparation of carboxylic acids or their esters as defined in at least one of claims 1 to 9.   11. Use of a catalyst system as in at least one of claims 1 to 4 defined for the production of carbon acids or their esters from olefins and carbon monoxide in Presence of water or alcohol.