| PATENT ASSIGNEE'S COUNTRY | Taiwan |
| UPDATE | 01.00 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 04.01.00 |
| PATENT TITLE |
Catalyst composition for preparing 3-pentenoic ester from butadiene |
| PATENT ABSTRACT |
A catalyst composition for the preparation of 3-pentenoic ester from butadiene. The catalyst composition includes a palladium complex; and a bidentate phosphine with the following formula: .sub.1 R.sub.2 P--(CH.sub.2)n--PR.sub.3 R.sub.4, wherein n is a integer from 1 to 6; and a bulky benzoic carboxylic acid. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 19.06.98 |
| PATENT REFERENCES CITED | This data is not available for free |
| PATENT CLAIMS |
What is claimed is: 1. A catalyst composition for preparing a 3-pentenoic ester from butadiene and an alcohol, comprising: (a) a palladium complex; (b) a bidentate phosphine ligand with the following formula: R.sub.1 R.sub.2 P--(CH.sub.2).sub.n --PR.sub.3 R.sub.4 ; wherein n is an integer from 1to 6, R.sub.1, R.sub.2, R.sub.3, R.sub.4, are, independently phenyl, naphenyl, or aromatic fused ring substituants, and (c) a bulky benzoic carboxylic acid, selected from the group consisting of 2,4,6-tri-isopropyl benzoic acid, 2,4,6-tri-tert-butyl benzoic acid, 2,4,6-tri-isobutyl benzoic acid, 2,6-di-isopropyl benzoic acid, 2,6-tri-tert-butyl benzoic acid, and 2,6-di-isobutyl benzoic acid. 2. The catalyst composition as claimed in claim 1, wherein the palladium complex is selected from the group consisting of palladium acetate, palladium acetylacetonate, and palladium hexafluoroacetylacetoneate. 3. The catalyst composition as claimed in claim 1, wherein the amount of the palladium complex is about 0.1 to 10 parts by mole. 4. The catalyst composition as claimed in claim 1, wherein the amount of the bidentate phosphine ligand is about 0.6 to 60 parts by mole. 5. The catalyst composition as claimed in claim 1, wherein the bulky benzoic carboxylic acid is selected from the group consisting of 2,4,6-tri-isopropyl benzoic acid, 2,4,6-tri-tert-butyl benzoic acid, 2,4,6-tri-isobutyl benzoic acid, 2,6-di-isopropyl benzoic acid, 2,6-tri-tert-butyl benzoic acid and 2,6-di-isobutyl benzoic acid. 6. The catalyst composition as claimed in claim 1, wherein the amount of the bulky benzoic carboxylic acid is about 1.0 to 100 parts by mole. 7. A catalyst composition for preparing a 3-pentenoic ester from butadiene and an alcohol, comprising: (a) a palladium complex; (b) a bidentate phosphine ligand with the following formula: R.sub.1 R.sub.2 P--(CH.sub.2).sub.n --PR.sub.3 R.sub.4 ; wherein n is an integer from 1 to 6, R.sub.1, R.sub.2, R.sub.3, R.sub.4, are, independently, phenyl, naphenyl, or aromatic fused ring substituants; and (c) wherein said bidentate phosphine ligand is selected from the group consisting of .alpha.,.alpha.'-diphenyl phosphino-o-xylene and 2,2'-bis(diphenylphosphino methyl)-1,1'-biphenyl. 8. A catalyst composition as claimed in claim 7, wherein the palladium complex is selected from the group consisting of palladium acetate, palladium acetylacetonate, and palladium hexafluoroacetylacetonate. 9. A catalyst composition as claimed in claim 7, wherein the amount of the palladium complex is about 0.1 to 10 parts by mole. 10. A catalyst composition as claimed in claim 7, wherein the amount of the bidentate phosphine ligand is about 0.6 to 60 parts by mole. 11. A catalyst composition as claimed in claim 7, which further comprises a bulky benzoic carboxylic acid selected from the group consisting of 2,4,6-tri-isopropyl benzoic acid, 2,4,6-tri-tert-butyl benzoic acid, 2,4,6-tri-isobutyl benzoic acid, 2,6-di-isopropyl benzoic acid, 2,6-tri-tert-butyl benzoic acid, and 2,6-di-isobutyl benzoic acid. 12. A catalyst composition as claimed in claim 11, wherein the amount of the bulky benzoic carboxylic acid is about 1.0 to 100 parts by mole. |
| PATENT DESCRIPTION |
FIELD OF THE INVENTION The present invention relates to a catalyst composition for preparing 3-pentenoic ester from butadiene. More specially, the invention relates to a catalyst composition which allows hydrocarbonylation of butadiene in the presence of carbon monoxide and an alcohol. BACKGROUND OF THE INVENTION The hydrocarbonylation of butadiene to obtain 3-pentenoic ester is a valuable process since 3-pentenoic ester is the starting material for the preparation of 5-formylvalerate esters, which are important intermediates for the preparation of caprolactam. Processes for preparing 3-pentenoic ester from hydrocarbonylation of butadiene are disclosed in U.S. Pat. No. 5,028,734 and U.S. Pat. No. 5,495,041. Both processes involve using butadiene to undergo the hydrocarbonylation reaction, providing 3-pentenoic ester as the major product. The catalyst for the hydrocarbonylation of butadiene disclosed in U.S. Pat. No. 5,028,734 is composed of a palladium complex, bidentate phosphine ligands and a benzoic carboxylic acid. The catalyst composition converts 75% of the butadiene to 3-pentenoic ester. The disadvantage of the catalyst is that another side reaction product, 2-pentenoic ester, is produced in addition to the 3-pentenoic ester in the reaction mixture. Thereby, the selectivity for 3-pentenoic ester using this catalyst composition is low. The other disadvantage of the invention is that the catalyst composition comprises benzoic acid, which can easily undergo esterfication in the presence of alcohols, thereby necessitating a constant feeding of the benzoic acid into the catalyst system to maintain efficient reactivity. Moreover, the co-catalyst can not be reused before hydrolysis and recovery. The hydrocarbonylation catalyst disclosed in U.S. Pat. No. 5,495,041 is composed of a palladium complex, bindenate phosphine ligands and 3-pentenoic acid. The drawback of this invention is that the conversion rate of butadiene is about 80%; however, the selectivity of 3-pentenoic ester is less than 50%. Therefore, the yield of 3-pentenoic esters according to the invention is too low. Both catalyst systems suffer from the disadvantage of that either extra benzoic acid must be constantly fed into the catalyst system to maintain sufficient catalytic activity or the selectivity of 3-pentenoic esters is low. Consequently, it is necessary to develop a catalyst composition which converts butadiene to give 3-pentenoic ester with high selectivity and which undergos hydrocarbonylation reaction without the requirement of constant feeding of co-catalyst. SUMMARY OF THE INVENTION It is therefore an object of the invention to develop a catalyst composition for preparing 3-pentenoic ester with high selectivity. More specially, the object of the invention is to develop a catalyst composition containing a bulky co-catalyst, which allow hydrocarbonylation to take place in the presence of carbon monoxide and an alkyl alcohol. The catalyst composition disclosed in the present invention comprises the following components: (a) 0.1 to 10 parts by mole of a palladium complex; (b) 0.6 to 60 parts by mole of a bidentate phosphine ligand; (c) 1.0 to 100 parts by mole of a bulky benzoic carboxylic acid. wherein the palladium complex is selected from the group consisting of palladium acetate, palladium acetylacetonate, or palladium hexafluoroacetylacetoneate; and the bidentate phosphine ligand can be expressed by the following formula: R.sub.1 R.sub.2 P--(CH.sub.2)n--PR.sub.3 R.sub.4, wherein n is a integer from 1 to 6, and R.sub.1, R.sub.2, R.sub.3, R.sub.4 can be independent phenyl, naphthyl, or aromatic compounds with fused ring structures. According to this invention, the ligands can be selected from .alpha.,.alpha.'-diphenyl phosphino-o-xylene or 2,2'-bis(diphenylphosphino methyl)-1,1'-biphenyl; the bulky benzoic carboxylic acid is selected from the group consisting of 2,4,6-tri-isopropyl benzoic acid, 2,4,6-tri-tert-butyl benzoic acid, 2,4,6-tri-isobutyl benzoic acid, 2,6-di-isopropyl benzoic acid, 2,6-tri-tert-butyl benzoic acid and 2,6-di-isobutyl benzoic acid. The improved catalyst composition disclosed in the present invention can be used in the presence of carbon monoxide and an alkyl alcohol for hydrocarbonylation of butadiene to provide 3-pentenoic esters with high selectivity and good yield. One of the advantage of the catalyst composition disclosed in the present invention is that the selectivity of 3-pentenoic ester is high, thereby providing 3-pentenoic ester with good yield. Another advantage of the catalyst composition disclosed in the present invention is that bulky benzoic acid derivatives which can not undergo esterfication in the presence of alkyl alcohols are used as the co-catalyst instead of conventional benzoic acid. Therefore, the undesired esterification of co-catalyst can be prevented, and supplemental amounts of co-catalyst are not needed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention discloses a catalyst composition for hydrocarbonylation of butadiene to give 3-pentenoic ester. The catalyst composition disclosed in the present invention allows the reaction to take place in the presence of carbon monoxide and a bulky carboxylic acid to give 3-pentenoic ester with high selectivity and provides a novel process of preparing 3-pentenoic ester that does not require supplemental amounts of co-catalyst. The catalyst composition disclosed in the present invention comprises the following components: (a) a palladium complex; (b) a bidentate phosphine ligand with a formula as R.sub.1 R.sub.2 P--(CH.sub.2).sub.n --PR.sub.3 R.sub.4 ; and (c) a bulky benzoic carboxylic acid. wherein the palladium complex is selected from the group consisting of palladium acetate, palladium acetylacetonate, or palladium hexafluoroacetylacetoneate, and the amount of the palladium complex is about 0.1 to 10 parts by mole; the bidentate phosphine ligand is selected from the group consisting of .alpha.,.alpha.'-diphenyl phosphino-o-xylene and 2,2'-bis(diphenylphosphino methyl)-1,1'-biphenyl, and the amount of the bidentate phosphino ligand is about 0.6 to 60 parts by mole; the bulky benzoic carboxylic acid is selected from the group consisting of 2,4,6-tri-isopropyl benzoic acid, 2,4,6-tri-tert-butyl benzoic acid, 2,4,6-tri-isobutyl benzoic acid, 2,6-di-isopropyl benzoic acid, 2,6-tri-tert-butyl benzoic acid and 2,6-di-isobutyl benzoic acid, and the amount of the bulky benzoic acid is about 1.0 to 100 parts by mole. The hydrocarbonylation process related to present invention can be conducted in a high-boiling inert solvent, such as C.sub.7 .about.C.sub.20 alkanes, arylalkanes or aryl ethers, thereby allowing the desired reaction product, 3-pentenoic ester, to be removed from the reaction mixture by distillation. The remaining catalyst components can be reused by feeding in another portion of the butadiene and charging the solution with carbon monoxide and alcohols for hydrocarbonylation. The present invention will now be described more specifically with reference to the following examples. It is to be noted that the following descriptions of examples, including the preferred embodiment of this invention, are presented herein for purposes of illustration and description, and are not intended to be exhaustive or to limit the invention to the precise form disclosed. |
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