DE3124720A1 - "METHOD FOR PRODUCING ALIPHATIC CARBONIC ACIDS" - Google Patents

Description

Müller, Schupfner & Gauger Karlstrafde 5

Patent attorneys J. 2110 Buchholz / Nordheide

06/16/1981

T-014 81 DE S / KB D 75,758-1-FB (WDH)

TEXACO DEVELOPMENT CORPORATION

2000 WESTCHESTER AVENUE
WHTIE PLAINS, NY 10650

UNITED STATES.

Process for the preparation of aliphatic carboxylic acids

Texaco Development Corp. T-014 81 DE D 75,758-1-FB

Process for the preparation of aliphatic carboxylic acids

The present invention relates to a process for the preparation of carboxylic acids by the homologation of aliphatic acids Carboxylic acids with synthesis gas using a specific catalyst system.

There is a growing need for a wide variety of aliphatic carboxylic acids having various numbers of carbon atoms and structures that have become important commodities. There are many methods of making these Acids, such as the oxidation of saturated and unsaturated hydrocarbons, the carboxylation of monoolefins, in particular ^ -Olefins and dienes such as the conjugated dienes, e.g. 1,3-butadiene, and the carbonylation of lower aliphatic Alcohols.

A new preparative route to short-chain aliphatic acids is emerging through the homologation of aliphatic carboxylic acids disclosed with low molecular weight. The homologation is achieved by treating the said carboxylic acids achieved with synthesis gas (a mixture of carbon monoxide and hydrogen).

The homologation of carboxylic acids by synthesis gas in the presence of the specific catalyst system of the present The invention has not yet been described. The homologation of saturated alkylbenzyl alcohols and substituted benzyl alcohols

■ "■ ·.: ■ ■.: ■. 312Λ720

by synthesis gas for the production of the corresponding alcohols with higher molecular weight has been intensively investigated. Other relevant examples are the homologation of methanol to ethanol and the conversion of ethanol to propanol, butanol and pentanol isomers (see: "Carbon Monoxide in Organic Synthesis" by J. Falbe, pp. 59-62 and I. Wender, Catal. Rev. Sci. Eng., 14, 97-129 (1976)). Cobalt carbonyls are generally! Applied with or without a phosphine or Metallmodifizierern as catalysts in such Alkoholhomologisierungen (see DE-OS 2 625 62? And USP 'h 111,837).

Related homogeneous cobalt carbonyl catalysts are also at effective in the synthesis of aliphatic carboxylic acids by carbonylation of lower aliphatic alcohols. In the last During the synthesis of acetic acid by carbonylation of methanol, soluble rhodium catalysts were increasingly used as Catalyst used (Chem. Tech., P. 6o5 »October 1971) ·

Another important technique of homologation is the recently described conversion of dimethyl ether and methyl acetate to ethyl acetate (see: G. Braca et al, 9 _S Amer, Chem.,, 100, 6238 (1978)).

The object of the present invention is to provide an improved method for homologating short-chain aliphatic carboxylic acids to their higher homologues by using a new catalyst system.

According to claim 1, the present invention relates to a process for the production of higher homologues of aliphatic Carboxylic acids with 2-6 carbon atoms derived from the Heating the aliphatic carboxylic acid starting material with

-χ- c

Carbon monoxide and hydrogen in the presence of a catalytic effective amount of one or more palladium or nickel containing Compounds in combination with a Group VB tertiary donor ligand and an iodide or bromide promoter a pressure of at least 35 »5 bar.

The method of the present invention is through homologation from acetic acid to higher acids according to equation 1 and specially marked:

CH ₃ COOH + C0 / H ₂ >. C _n H _{2n + 1} COOH (1)

Other lower aliphatic acids like propionic acid and. others with 2-6 carbon atoms can accordingly implemented.

The method of the present invention for manufacture higher homologs of aliphatic carboxylic acids with 2-6 carbon atoms consists of bringing the aliphatic into contact Acid starting material with a catalytically effective amount of a palladium or nickel containing Compound in combination with a tertiary donor ligand of Group VB and in the presence of an iodide or bromide promoters and heating the resulting reaction mixture with carbon monoxide and hydrogen at a pressure of at least 35 »5 bar until a substantial formation of the desired acids with at least 3 carbon atoms has been achieved.

The homologation of the present invention becomes selective carried out to produce higher homologs of the aliphatic carboxylic acid used, it is desirable at least add sufficient carbon monoxide and hydrogen, to meet the stoichiometry of the desired higher carboxylic acid homologues; however, there can also be an excess Carbon monoxide and hydrogen are present.

In contrast to the prior art that concern the carbonylation of lower aliphatic alcohols to carboxylic acids, it was found that homologation can only be achieved with the synthesis gas mixture and that carbon monoxide alone is not sufficient.

It was also found that an iodide or bromide promoter is necessary to carry out the acid homologation according to the scheme described above. Surprisingly, it was finally determined that low Alkyljodid- or Alkylbromidpromoter are much more effective than bromides or alkali metal iodides such, B _a cesium iodide "

The method of the present invention will now be described in detail.

The catalysts suitable for the process according to the invention contain palladium or nickel. They can, as constricting the fol ~ is described in more detail, ₉ complexes are uswo selected from a variety of organic or inorganic compounds is "only important _s that the applied Kätalysatorvorstufe palladium or nickel in ionic form" It is believed that the catalytically the really active compound is a complex of palladium or nickel with carbon monoxide and hydrogen. The catalyst is most effective when the palladium or nickel hydrocarbonyl complex is partially dissolved in the carboxylic acid coreactant used to satisfy the stoichiometry of equation 1 "

The palladium catalyst precursors can be in various forms. Thus, the palladium may be added to the reaction mixture z »B _o as an oxide such as palladium (il) ~ oxide (PdO) ,, It may also be a salt of a mineral acid, for example, as palladium (ll) - ₍₂ PdCl) ₉ palladium = hydrochloride ( il) bromide (PdBr ₃ ) ₉ palladium (ll) iodide (PdJ), anhydrous palladium (ll) -

chloride (PdCl ₂ ) or palladium nitrate (Pd (NO) χ HpO) or as a salt of a suitable organic carboxylic acid, for example palladium (II) acetate or palladium (II) acetylacetonate.

Preferred palladium-containing compounds are palladium oxides, Palladium salts of a mineral acid and palladium salts of organic carboxylic acids. Are particularly preferred Palladium (II) acetate, palladium acetylacetonate and palladium oxide.

The nickel catalyst precursors can also be in various forms. The nickel can be added to the reaction mixture as an oxide, such as nickel (II) oxide (NiO), nickel (III) oxide (Ni ₂ O ₃ 6 H ₂ O) and nickel (II) (III) oxide (NiO , Ni ₂ O ₃ ) can be added. It can also be used as a salt of a mineral acid, e.g. Niekel (II) chloride (NiCl ₂ ), nickel (II) chloride hydrate (NiCl ₂ χ 6 H ₂ O), nickel (II) bromide (NiBr ₂ ), nickel ( II) bromide hydrate (NiBr „χ H„ 0), nickel iodide (NiJ ₀ ) or nickel (il) nitrate hydrate (Ni (NO) χ 6 Η _ρ θ); or as a salt of a suitable organic carboxylic acid such as nickel (II) formate, nickel (II) acetate, nickel (II) propionate, nickel (II) naphthenate, nickel (III) acetylacetonate, etc. are added. The nickel can also be added to the reaction mixture as a carbonyl or hydrocarbonyl derivative. Suitable examples of this are nickel tetracarbonyl (Ni (CO ¹ K), as well as hydrocarbonyls and substituted carbonyls such as bis (triphenylphosphine) nickel dicarbonyl and bis (triphenylphosphite) nickel dicarbonyl.

Preferred nickel-containing compounds are nickel oxides, nickel salts of mineral acids or organic carboxylic acids and nickel carbonyl or hydrocarbonyl derivatives. Particularly nickel (II) acetylacetonate, nickel (II) acetate are preferred, Nickel (il) propionate and Niekelcarbonyl.

In the present invention, the palladium or nickel can be added to the reaction mixture in the form of one or more oxide, salt or carbonyl derivatives as a complex with one or more tertiary donor ligands of Group VB. However, if desired, the ligand can also be added separately to the reaction mixture. The key elements of the group Vβ ligands are nitrogen, phosphorus, arsenic and antimony. These elements, especially nitrogen and phosphorus, can be bound in their trivalent oxidation state to one or more aliphatic, cycloaliphatic, aromatic, substituted aromatic, aryloxy, alkoxy or mixed aliphatic-aromatic radicals, each with up to 12 carbon atoms, or they can be part of a heterocyclic ring system or Be mixtures of the same. Examples of suitable ligands in the present invention are: triphenylphosphine, tri-n-butylphosphine, triphenylphosphite, triethylphosphite, trimethylphosphite, trimethylphosphine, tri-p-methoxyphenylphosphine, triethylphosphine, trimethylarsine, triphenylarsine, trihexylphosphine, trolylphosphine, trihexylphosphine, trolylphosphine Triοctylphosphin, tri-o-tolylphosphinj 1 ₉ 2-bis (dipheny! phosphine) ethane, triphenylstibine, trimethylamine, triethylamine, _{tripropylamine?} Tri-n-octylamine, pyridine ₉ 2j 2 ^! -Dipyridyl, 1, lo-phenanthroline, quinoline, N, N »-dimethyl = piperazine _? 1 ₅ 8-bis (dimethylamine) naphthalene and N ₉ N'-dimethylaniline "

One or more of these combinations of palladium or nickel with tertiary donor ligands of group VB can be preformed before addition to the reaction mixture, for example _o in the case of bis (triphenylphosphine) palladium chloride ₉ bis (triphenylphosphine) palladium (II) acetate and tetrakis (triphenylphosphine) palladium (O), bis (1,2-diphenylphosphine) ethane nickel (II) chloride, dicarbonylbis (triphenylphosphine) nickel and tetrakis (triphenylphosphite) nickel (o). However, the complexes can also be formed in situ, the palladium- or nickel-containing compound and the ligand being added separately. The production of such complex

Combinations of palladium or nickel with tertiary donor ligands Group VB is detailed in U.S. Patent 3,1o2,899 and U.S. Patent 3,560,539.

The amounts of that used with the palladium or nickel compound Group VB tertiary donor ligands can range over a wide range, e.g., from that to form a complex stoichiometric with the palladium or nickel compound necessary amount up to five times or more this amount.

The iodide required for the desired acid homogenization or bromide promoter can be used in combined form along with the palladium or nickel, such as in palladium (II) chloride or nickel iodide are present. But it will generally be a An excess of halogen is preferred as a promoter in the catalyst system. With excess is meant an amount of halogen that is at there is more than 3 atoms of halogen per atom of palladium or nickel in the catalyst system. This promoter of the catalyst system can be composed of a halogen and / or a halogen compound consist of the reaction mixture as a gas or liquid or saturated in a suitable solvent or reactant can be added. Satisfactory halogen promoters are hydrogen halides such as hydrogen iodide and

Hydriodic acid, alkyl, aryl and aralkyl halides with up to 12 carbon atoms, such as methyl iodide, ethyl iodide, 1-iodopropane, 2-iodobutane, 1-iodobutane, ethyl bromide, iodobenzene and benzyl iodide as well as acyl iodides such as acetyl iodide. The quaternary ammonium and phosphonium halides are also suitable as halogen co-reactants; Examples are Tetramethylammonium iodide and tetrabutylphosphonium iodide. Alkali metal and alkaline earth metal halides such as cesium iodide can also be used, but they are homologous for this generally not as effective as the other promoters listed.

Alkyl iodide or bromide promoters having 1 to 6 carbon atoms are the preferred promoters in the palladium or nickel catalyzed Acid Homologation of the Present Invention. Methyl iodide and ethyl iodide are particularly preferred.

Carboxylic acids suitable as starting materials for the process according to the invention are aliphatic carboxylic acids having 2 to 6 carbon atoms. Said acids are preferably also suitable as solvents for the palladium or nickel catalysts. Suitable carboxylic acids are acetic acid, propionic acid, butyric acid, isobutyric acid, VaIeriansäure, trimethylacetic acid and caproic acid, together with aliphatic dicarboxylic acids having 2 to 6 carbon atoms, such as oxalic acid _f malonic acid, succinic acid and adipic acid. The invention further includes the use of substituted aliphatic acids with one or more substituents, such as lower alkoxy, chlorine, fluorine, phenyl, substituted phenyl, cyano, alkylthio and amino groups, examples of which are acetoacetic acid, dichloroacetic acid, trifluoroacetic acid , Chloropropionic acid, trichloroacetic acid, monofluoroacetic acid and the like. In the process according to the invention, mixtures of the said carboxylic acids can also be used in any ratio. The preferred carboxylic acids for homologation according to the present invention are acetic acid and propionic acid, with acetic acid being most preferred »

The amount of palladium or nickel compound used in the present invention is not critical and can be vary over a wide range. In general, the novel process is preferred in the presence of a catalytically active one Amount of one or more active palladium or nickel compounds carried out, whereby the desired products are obtained in sufficient quantities. The reaction is running already from "if amounts as small as 1 χ 1o wt"? £ or even less of palladium or nickel, based on the total = weight of the reaction mixture. The upper concentration limit is determined by a variety of factors

determined as the catalyst cost, partial pressures of carbon monoxide and hydrogen, reaction temperature and choice of the carboxylic acid / reactant tone. In general, a catalyst concentration of 1 χ Io to 1o wt. ° / ₀ palladium or nickel, based on the total weight of the Reakti ons mixtures s, in the practice of the present invent * HS Hangeul chenswert.

The temperature range used in these syntheses is variable and dependent on other experimental factors such as the choice of the carboxylic acid co-reactant, the pressure, and the concentration and type of catalyst, among others. Will If superatmospheric pressures are applied, the temperature will be in a range of 100 to about 35 ° C. The preferred range is around 18o to around 25o C.

Superatmospheric pressures of at least 35> 5 bar lead to substantial yields in the process according to the invention desired higher homologs of the aliphatic carboxylic acids. A preferred pressure range is 69.9 to 518.2 bar, although pressures above 518, 2 bar useful yields of the provide the desired acid. The pressures mentioned here are composed of the total pressure obtained by all reactants, although this is mainly due to the carbon monoxide and hydrogen proportions in these examples.

The relative amounts of carbon monoxide and hydrogen initially included in the synthesis mixture are variable and can vary over a wide range. In general, the CG / H Lm molar ratio will range from about 20: 1 to about 1: 2o, preferably from about 5: 1 to 1: 5, although ratios outside this range can also be employed. Be applied particularly in continuous, but also in batch operations, may the carbon monoxide / hydrogen gas mixture also in conjunction with up to 5 ° vol. ° / o einos or more other gases. These other gases can be one or more inert gases such as nitrogen, argon, neon

and. be similar, or they can be gases that are among the CO hydrogenation conditions react or not react, like carbon dioxide, hydrocarbons like methane, ethane, Propane and similar, ethers such as dimethyl ether, methyl ethyl ether and diethyl ether, alkenols such as methanol and esters such as methyl acetate.

In all of these syntheses must have a high degree of selectivity to achieve the amount of carbon monoxide and hydrogen in the reaction mixture so large that at least the stoichiometry of equation 1 is met. If desired, an excess of carbon monoxide and / or Hydrogen can be applied.

As far as can be determined and without the invention thereby the one-step process of acid homologation disclosed here leads to the formation of acid products, which contain one more carbon atom than the starting material. Usually small amounts of higher acid homologues with 2 or 3 additional carbon atoms are also used, obtain. If acetic acid is the coreactant, Sinti is the main product Propionic acid, butyric acid and valeric acid. In the liquid product phase there are also by-products such as water and ethyl acetate. If propionic acid is the reactant, then so the main products are n-butyric acid and iso-butyric acid. The ratio of normal to iso acids is generally about 3: 1.

The new process of the present invention can be carried out in batch, semi-continuous or continuous operation be performed. The catalyst can be added batchwise to the reaction zone right at the start, or it can continuously or in batches during the synthesis. will be added. The operating conditions can be adjusted so that an optimal formation of the desired acid product is ensured, and the said material can by methods known to those skilled in the art, such as distillation, fractionation,

Extraction and the like have been obtained. A fraction rich in palladium or nickel can, if desired, the Reaction zone are added again and thus serve to produce further products.

The products of this work were prepared by one or more or a combination of the following analytical methods identified: gas chromatography (Ge), infrared spectroscopy pie (IR), mass spectrometry, nuclear magnetic resonance spectroscopy (NMR) and elemental analysis. The analyzes are usually given in parts by weight; all temperatures in C and all pressures in bar.

The following examples show preferred ones. Embodiments the invention.

example 1

To a liquid mixture of 25 g of acetic acid and 8.0 g of methyl iodide (56 mmol) flushed with nitrogen in a glass reactor were 0.4 g of palladium acetate (1.8 mmol) and 4.0 g of triphenylphosphine (15 mmol) given. The mixture was stirred to partially dissolve the palladium acetate and the glass reactor together with its contents placed in a 45o ml shaking autoclave. The reactor was flushed with a gaseous mixture of equimolar parts of carbon monoxide and pulp brought the same gas mixture to a pressure of 138.9 bar and heated to 22o C with shaking. Then there was the pressure with the carbon monoxide / hydrogen gas mixture to 435 »5 bar increased and during the experiment by adding carbon monoxide / water held at this pressure from a storage tank.

After cooling, depressurizing and taking an exhaust gas sample, 32.6 g of a clear, deep red liquid were obtained Product won. There was also a small amount (Xl ml) discovered a lighter liquid phase. The GC analysis of the main phase showed:

13.2% propionic acid

1.1 per cent butyric acid

0.5 % valeric acid

16, ο "/ ο What s he

47.8% unreacted acetic acid

Typical exhaust gas samples had the following analyzes:

45 % carbon monoxide

22 »/ ο hydrogen

13 ° / o carbon dioxide

15 per cent methane

Examples 2 to 4

According to the general method described in Example 1, further catalyst combinations were used.

Ί) Examples 2 and 3 show the use of different initial palladium (II) acetate / triphenylphosphine molar ratios, the reactor initially with a mixture of equimolar amounts of carbon monoxide and Hydrogen is put under a pressure of 276.8 bar and the homologation of acetic acid is carried out under variable pressure conditions,

Z) Example 4 shows the use of bis (triphenylphosphine) palladium (II) chloride as a catalyst precursor,

Examples A-H

Following the method described in Example 1, a series of experiments using a large number of others Catalysts with methyl iodide as promoter and acetic acid carried out as a carboxylic acid starting material »The results summarized in Table I show that platinum, cobalt, Iron, manganese, rhenium, molybdenum and chromium catalysts in the homologation of acetic acid to higher carboxylic acids are ineffective.

Table I.

Composition of the liquid product - _

At- Group VB aliphatic

game catalyst ligand promoter acid HOBu

HOVa

H O HOAc HOPr Iso η tert iso η

Pd (OAc) ₂
Pd (OAc) ₂
Pd (OAc) ₂

Ph ₃ P
Ph ₃ P
Ph P

) ₂ ci

CoJ

Co ₂ (CO) ₈
Fe (AcAc)

Mo (AcAc) "
Cr (AcAc) -

- 31 months

- 31 months

- 31 months

- 28 months

- 1o May

- 5 MeH

- Io MeJ

- 5 months

- 5 months

- 1o May

- 1o May

HOAc HOAc HOAc

- 31 MeJ HOAp

HOAc HOAc HOAc HOAc HOAc HOAc HOAc HOAc 16.0 47.8 13.2 0.7 0.4 0.5 1o, 8 64.8 13.2 0.7 o.4 1.0 0.9 0.8

o, 5 27.9 8, ο 1.8

2o, 1 48.8 1o, o 1.3,

Xv A. J \. X

o.9 37.4 6.3 o.2 o.5

13, S ₁ 63.4 _χ 7, I ₁ o, ^

5.1 8o, 1

2.4 95.4

3.9 9o, 1

2.3 95.2 o, 5 97.8 o, 7 97.5

1.1 93.6 o, 2

5.4 89.7 o, 5

Ο, 1 · | Ο, 4

1 O, 1 CO O, 6th O" 2 N> O,

Table I (continued)

Use: 25 g aliphatic acid, 56 mmol iodide promoter, 1.8 mmol catalyst. Use: 5 ° g aliphatic acid, ko mmol iodide promoter, h, ο mmol catalyst,

Use: 5 ° g aliphatic acid, 112 mmol iodide promoter, 4, ο mmol catalyst. Use: 5 ° g aliphatic acid, 2o mmol iodide promoter, 4, ο nfcnol catalyst.

Operating conditions: initial pressure 276.8 bar of CO / Hp (i: i), 220 ° C, 18 h. Meanings: propionic acid HOPr, butyric acid HOBu and VaXeric acid KOVa.

Two-phase liquid product, the heavier phase (k) is 86 % of the product. Two phase s liquid product, the heavier phase (l) is Sk % of the product.

A small amount of a lighter liquid phase was observed. Operating conditions: constant pressure 435.5 bar, C0 / H ₂ (1: 1) to 22O ⁰ C, 18 h.

Example 5

According to the method described in Example 1, 0.5o g Nickel (il) acetate (2, ο mmol Ni) and 1.43 g triphenylphosphine (5 »4 mmol) used.

After cooling, depressurizing and taking an exhaust sample, 33.9 g of a dark brown liquid product were obtained. The GC analysis showed:

7 »6 % propionic acid
0.6 per cent. Butyric acid
o, 4 ° / o valeric acid 8.2 ° / o water
75 »1 ° / o unreacted acetic acid

Typical exhaust gas samples had the following analyzes:

57% Kohlenstoffmonoxxd 34 o / o hydrogen

2 ° / o carbon dioxide, 2 ° / o methane

Example 6

A second experiment was carried out using a triphenylphosphine-nickel carbonyl complex, (Ni (PPh ") ₂ ( ^c0 ) 2 ^", according to the general method described in Examples 1 and 5. The results are summarized in Table II.

Table II Composition of the liquid product

J "

HOVa

At- Group VB aliphatic ^& HOBu

game catalyst ligand promoter acid H ₀ O HOAc HOPr I so η tert iso n ~

k, m l, m

28 MeJ HOAc 1o MeJ HOAc

8.2 75.1 7.6 o, 2 o, 4
5.2 82.7 4.9 o, 4

Operating conditions: constant pressure 435.5 bar of C0 / H _o (1: 1), 22o C, 18 h.

o, 2 o, 2
o, 9 o, 1

Use: 25 g aliphatic acid, 56 mmol iodide promoter, 2, ο mmol catalyst

Use: 5o g aliphatic acid, 4o mmol iodide promoter, 4, ο mmol catalyst, Catalyst and ligand were added as a complex.

Claims (9)

Claims / 1. A process for the preparation of higher homologues of aliphatic ^ ^ tischen carboxylic acids with 2 to 6 carbon atoms, characterized in that the aliphatic carboxylic acid with carbon monoxide and hydrogen in the presence of a catalytically effective amount of at least one compound containing palladium or nickel, a tertiary donor ligand of Group VB of the periodic table and a dodide or bromide promoter is reacted at a pressure of at least 35.5 bar with heating. 2. The method according to claim 1, characterized in that the reaction is carried out at a temperature in the range of 100 to 35O ⁰ C, preferably in the range of 180 to 25O ⁰ C. 3. The method according to claim 1 or 2, characterized ge indicates that the implementation at a Pressure in the range of 69.9 to 518.2 bar is carried out. Method according to one of Claims 1 to 3, characterized characterized in that the compound containing palladium or nickel is an oxide or a salt a mineral acid or an organic acid. 5. The method according to any one of claims 1 to 4, characterized in that as Palladium-containing compound palladium (II) acetate, Palladium (II) acetylacetonate. Palladium (II) chloride or Palladium oxide is used. 6. The method according to any one of claims 1 to 3, characterized in that as Nickel-containing compound nickel (II) chloride, nickel (II) oxide, nickel (II) acetylacetonate, nickel (II) acetate, Nickel (II) propionate or nickel carbonyl. Is used. 7. The method according to any one of the preceding claims, characterized in that as tertiary donor ligand triphenylphosphine, trimethylphosphine, Tri-n-butylphosphine, triphenyl phosphite, triethyl phosphite, Triphenylarsine, trimethylamine, triethylamine, tripropylamine or tri-n-octylamine is used. 8. The method according to any one of the preceding claims, characterized in that an alkyl iodide or bromide with 1 to 6 carbon atoms, preferably with 1 to 2 carbon atoms, is used as a promoter. 9. The method according to any one of the preceding claims, characterized in that as aliphatic carboxylic acid acetic acid is used as the starting material.