WO2000007973A1

WO2000007973A1 - Method for producing sorbic acid and sorbic acid esters or derivatives thereof

Info

Publication number: WO2000007973A1
Application number: PCT/EP1999/005167
Authority: WO
Inventors: Thomas Barth; Norbert Rieber; Klaus Breuer; Martin Schäfer; Justin Wolf; Helmut Werner
Original assignee: Basf Aktiengesellschaft
Priority date: 1998-08-07
Filing date: 1999-07-20
Publication date: 2000-02-17
Also published as: DE19835783A1; AU5285699A; CA2339736A1; EP1102740A1; JP2002522408A

Abstract

The invention relates to a method for producing compounds of formula (I) in which R1 = H, C¿1?-C6 alkyl, C1-C6 alkenyl, C3-C6 cycloalkyl or phenyl and R?2¿ = H or C¿1?-C3 alkyl, whereby propyne is reacted with a compound of formula (II), in which R?1 and R2¿ have the above-mentioned meanings, in the presence of a transition metal catalyst system.

Description

Process for the preparation of sorbic acid and sorbic acid esters or their derivatives

description

The invention relates to a process for the preparation of sorbic acid and sorbic acid esters or their derivatives. Sorbic acid is currently produced on an industrial scale by reacting crotonaldehyde and ketene (DE 1 042 573, DE 1 059 899). However, the manufacture and handling of ketene is complex and requires complicated process engineering.

Other processes for the production of sorbic acid and its esters are also described in the literature.

DE-OS 25 54 403 (US Pat. No. 3,966,798) discloses a process for the catalytic coupling of allyl compounds to substituted olefins, with which sorbic acid esters from allyl alcohol and acrylic acid esters or acrylate and propene (but only "in traces", see Example 5) are producible.

EP 55 936 discloses a process by which sorbic acid can be prepared from butadiene and acetic acid via an intermediate (acetoxyhexenoic acid).

The reaction of acetylene with acrylic compounds is described in JACS 1952, 74, 5636-5640, it being expressly pointed out that 2 moles of acetylene are reacted per reaction step.

From J. of. Organometallic Chemistry, 394 (1990), 569-581 it is known that 1-alkynes can be reacted with 3-butenecarboxylic acid on rhodium catalysts, a series of branched products, but not sorbic acid, being produced in the case of 1-alkyl-acetylenes.

From Tetrahedron Lett. 39 (1998), 7361-7364, it is known that phenylacetylene can be reacted with inactivated olefins such as methyl 4-pentenoate or 4-pentenoate nitrile over a ruthenium catalyst, conjugated dienes being formed, but not with the carboxyl group conjugated alkadiene system such as sorbic acid and its esters.

The object of the present invention was to provide a process for the preparation of sorbic acid and its esters or their derivatives from easily accessible starting materials To provide, which does not have the disadvantages of the prior art and provides the end product in high yields with respect to the acrylic compound reacted.

This object was achieved by a process in which propyne (methylacetylene) and / or propanediene (Allen) in the presence of a transition metal catalyst system with a compound of the formula II

0

H ₂ C

^ C

^" OR ¹ II

R ²

in which R ¹ = H, -C ₆ alkyl, -C ₆ alkenyl, C ₃ -C ₆ cycloalkyl or phenyl, which may optionally be substituted, and R ² = H or -C ₃ alkyl , is implemented.

The process product is a compound of formula I.

in which R ¹ and R ² can have the meanings given above. The alkyl or alkylene groups R ¹ and R ² can be straight-chain or branched.

Preferably R ¹ = H or -CC ₄ alkyl and R ² = H, ie the compound of formula I is preferably sorbic acid or its -C-C ₄ alkyl ester, preferably the methyl, ethyl or butyl ester.

The transition metal catalyst system preferably consists of a transition metal compound and a phosphine ligand.

In a special embodiment of the invention, in addition to the phosphine ligand, a phosphonium salt is additionally added to the catalyst system. Alternatively, an acid can be added to excess phosphine ligand.

The transition metal is preferably rhodium. Suitable catalysts are, for example, rhodium, ruthenium or nickel complexes in combination with monodentate or bidentate phosphine ligands in a range from 0.1 to 10.0 mol% (the mol percentages given in each case relate to the compound of the formula used II.). Especially preferred are, among others Rhodiumtris (riarylphosphin) chloride, Hydridodichlororhodium- bis (triarylphosphine), Alkyldichlororhodiumbis (triarylphosphine) Vinyldichlororhodiumbis (triarylphosphine), cyclopentadienyl rutheniumbis (triarylphosphine) chloride or Nickeldicarbonyl- bis (triarylphosphine), very particularly preferably Rhodiumtris (triphenylphosphine ) chloride, hydridodichlororhodium bis (triphenylphosphine), (R ¹ OOCCHR ² -CH ₂ ) dichlororhodium bis (triphenylphosphine), (C ₃ H ₅ ) dichlororhodium bis (triphenylphosphine), cyclopentadienyl ruthenium bis (triphenylphosphine) chloride or (nickel) dicarbonyl bis (nickel dicarbonyl) in the range of 1.0 to 5.0 mol%.

As the phosphine ligands, the ligands occurring in the complexes are added to the reaction solution in the range from 0.4 to 40 mol%, particularly preferably 1 to 10 mol%. Mixtures of the ligands occurring in the complexes (0.4 to 40 mol%, particularly preferably 1 to 10 mol%) and further monodentate or bidentate phosphine ligands in the range from 0.1 to 10.0 mol% can also be used. %, very particularly preferably 1 to 10 mol%, are used. As ligands e.g. Triphenylphosphine, tributylphosphine, tricyclohexylphosphine, tris (o-methoxyphenyl) phosphine, tris (2,4,6-trimethylphenyl) phosphine, tri-o-tolylphosphine, tris (3-chlorophenyl) phosphine, bis (2-diphenylphosphinoethyl) phe- nylphosphine (triphos) and tris (2-diphenylphosphinoethyl) phosphine (tetraphos) in question. As multidentate ligands e.g. Bis (diphenylphosphino) methane, ethane or propane or 1,1,1-tris (diphenylphosphinomethyl) ethane used.

As phosphonium salts e.g. Trialkylphosphonium chloride, bromide, trifluoromethanesulfonate, tetrafluoroborate or triaryl phosphonium chloride, bromide, trifluoromethanesulfonate, tetrafluoroborate used in the range from 0.001 to 40 mol%. Triphenylphosphonium chloride or triphenylphosphonium bromide in the range from 0.01 to 20 mol% are particularly preferred. In a particular embodiment, an organic or inorganic acid is added to a phosphine. Hydrogen chloride, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid, tetrafluoroboric acid, trifluoromethanesulfonic acid or acetic acid are particularly preferred.

The process according to the invention is preferably carried out in an organic solvent. Suitable solvents are ethers, hydrocarbons, cyclic amides, lactones or alcohols. Tetrahydrofuran, dioxane, ethylene glycol diethyl ether, benzene, toluene, xylene, gasoline, cyclohexane, N-methylpyrrolidone, γ-butyrolactone, methanol, ethanol, propanol or butanol are particularly preferred.

Furthermore, the acrylates used, propyne in condensed form or mixtures thereof can be used as solvents.

The process is preferably carried out at 20 to 200 ° C, particularly preferably at 40 to 120 ° C, and a pressure of 1 to 60 bar, preferably 1 to 20 bar, particularly preferably 1 to 5 bar. The sorbic acid or the sorbic acid esters or their derivatives are obtained as trans-trans and cis-trans isomer mixtures.

The propyne and / or propadiene can be used in the process according to the invention in a mixture with other hydrocarbons. This mixture can e.g. the propyne-containing fraction of the cracking gas treatment of a steam cracker or a propyne-propadiene mixture (MAPD).

It is a particular advantage of this process that mixtures of this type can also be used because these mixtures represent a favorable starting product base and lead to the desired product without a further refining step. The addition of the propyne to the compound II surprisingly leads directly to the hexadiene system of the compound I.

Examples

example 1

32 g of butyl acrylate (0.25 mol), 2.9 g of rhodium tris (triphenylphosphine) chloride (3.13 mol, 1.25 mol%) and 4.12 g of triphenylphosphine (15.7 mmol, 5 , 0 mol%) dissolved. A propyne stream (4 l / h) was introduced into this mixture at 65 ° C. over 20 hours. The reaction discharge was then analyzed by GC analysis. With an acrylate conversion of 10%, a butyl sorbate selectivity of 90% was determined. Acrylate determined. Example 2

32 g of butyl acrylate (0.25 mol), 2.9 g of rhodium tris (triphenylphosphine) chloride (3.13 mmol, 1.25 mol%), 1.25 g of bis (diphenylphosphino) ethane (3, 13 mmol, 1.25 mol%) and 4.12 g triphenylphosphine ^' (15.7 mmol, 5.0 mol%) dissolved. A propyne stream (4 l / h) was introduced into this mixture over 20 hours at 100 ° C. The reaction discharge was then analyzed by GC analysis. With an acrylate conversion of 10%, a butyl sorbate selectivity of 80% was determined. Acrylate determined.

Example 3

33.9 g of butyl acrylate (0.26 mol), 0.92 g of cyclopentadienylruthenium bis (triphenylphosphine) chloride (1.25 mmol, 0.5 mol%) and 0.26 g of sodium hexafluorophosphate (1.5 mmol , 0.6 mol%) dissolved. A propyne stream (2 l / h) was introduced into this mixture over 16 hours at 100 ° C. The reaction discharge was then analyzed by GC analysis. With an acrylate conversion of approx. 21%, a butyl sorbate selectivity of 21% was determined. Acrylate determined.

Example 4

4.3 g of methyl acrylate (0.05 mol), 0.58 g of rhodium tris (triphenylphosphine) chloride (0.626 mmol, 1.25 mol%) and 0.82 g of triphenylphosphine (3.14 mmol, 6 , 3 mol%) dissolved. A stream of propyne (2 l / h) was introduced into this mixture at 65 ° C. over 23 hours. The discharge from the reaction was then examined by GC analysis. With an acrylate conversion of 30%, a methyl sorbate selectivity of 27% was determined. Acrylate determined (after correcting stripping losses on methyl acrylate: selectivity:> 90%).

The following examples were carried out with the addition of a phosphonium salt.

Example 5

in 43 g of methyl acrylate (0.5 mol) were 0.58 g of rhodium tris (triphenylphosphine) chloride (0.625 mmol, 0.125 mol%) and 0.21 g of triphenylphosphine hydrobromide (triphenylphosphonium bromide, PPh ₃ ^• HBr) (0.625 mmol, 0.125 mol%) dissolved. A propyne stream (2 l / h) was introduced into this mixture at 60 ° C. for 20 hours. The reaction discharge was then subjected to GC analysis. is looking for. With an acrylate conversion of 12%, a methyl sorbate selectivity of 10% was determined. Acrylate determined.

Example 6

In 43 g of methyl acrylate (0/5 mol) 0.58 g of rhodium tris (triphenylphosphine) chloride (0.625 mmol, 0.125 mol%) and 0.64 g of triphenylphosphine hydrobromide (triphenylphosphonium bromide, PPh ₃ • HBr) (1.875 mmol, 0.375 mol%) dissolved. A propyne stream (2 l / h) was introduced into this mixture at 60 ° C. for 20 hours. The reaction discharge was then analyzed by GC analysis. With an acrylate conversion of 17%, a methyl sorbate selectivity of 6% was determined. Acrylate determined.

Example 7

In 64 g butyl acrylate (0.5 mol) 0.58 g rhodium tris

(triphenylphosphine) chloride (0.625 mmol, 0.125 mol%) and

0.21 g triphenylphosphine hydrobromide (triphenylphosphonium bromide, PPh ₃ • HBr) (0.625 mmol, 0.125 mol%) dissolved. A propyne stream (2 l / h) was introduced into this mixture at 80 ° C. for 20 hours. The reaction discharge was then analyzed by GC analysis. With an acrylate conversion of 2%, a methyl sorbate selectivity of 18% was determined. Acrylate determined.

Claims

claims

1. Process for the preparation of compounds of formula I.

H ^• H 0

R ¹ = H, Cι-C ₆ -alkyl, C _e alkenyl, C ₃ -C ₆ -cycloalkyl or phenyl and R ² = H or Cι-C ₃ alkyl,

characterized in that propyne and / or propadiene with a compound of formula II

O

II ^HC ^ .C

R ² in which R ¹ and R ^{2 have} the meanings given above, is reacted in the presence of a transition metal catalyst system.

2. The method according to claim 1, characterized in that R ¹ = H or -CC ₄ alkyl.

3. The method according to claim 1, characterized in that R ² = H.

4. The method according to claim 1, characterized in that the transition metal catalyst system from a transition metal

Compound and a phosphine ligand.

5. The method according to claim 1, characterized in that it is carried out in an organic solvent.

6. The method according to claim 4, characterized in that the organic solvent is an ether, a hydrocarbon, a cyclic amide, a lactone, an alcohol or a mixture of these solvents.

7. The method according to claim 1, characterized in that it is carried out at temperatures of 20 to 200 ° C.

8. The method according to claim 1, characterized in that the propyne and / or propadiene is present as a mixture with other hydrocarbons.

9. The method according to claim 1, characterized in that rhodium is used as transition metal.