| abstract |
The invention relates to a carbonylation process for the preparation of a compound of formula (I) XOOC-(CH 2 ) 4 -COOY (I) wherein X and Y can independently represent H and/or alkyl, said carbonylation process comprising reacting: (a) a composition comprising at least one isomeric methyl pentenoate; (b) a source of Pd; (c) a bidentate di-phosphine of formula II, R 1 R 2 P - R 3 - R - R 4 - PR 5 R 6 (II) wherein P represents a phosphorus atom; R 1 , R 2 , R 5 and R 6 can independently represent the same or different optionally substituted organic groups containing a tertiary carbon atom through which the group is linked to the phosphorus atom; R 3 and R 4 independently represent optionally substituted lower alkylene groups and R represents an optionally substituted aromatic group; (d) a source of anions derived from an acid with a pKa < 3; (e) carbon monoxide; and (f) an OH group comprising compound, under conditions wherein (I) is produced, characterized in that the least one isomeric methyl pentenoate comprises methyl 2-pentenoate. The process advantageously has a high conversion rate and may be used without the need to separate methyl 2-pentenoate from mixtures also containing methyl 3- and/or 4 pentenoate in order to isomerise the methyl 2-pentenoate. The process is suitable for the production of dimethyl adipate, adipic acid and hexamethylene diamine and products derived thereof such as nylon 6,6 from renewable sources such as plant waste, sewage waste etceteras instead of using fossil sources. |