Patent ID: 7553991

Claim:
A process for producing carboxylic acid anhydrides, in which a carboxylic acid ester, derived from an alcohol and a carboxylic acid, and carbon monoxide containing a small amount of hydrogen are used as raw materials and subjected to a carbonylation reaction in a liquid reaction medium in the presence of a Group VIII B catalyst to produce a carboxylic acid anhydride, the reaction medium comprising the Group VIII B catalyst, an organic halide, the carboxylic acid ester, an alkali metal salt, the carboxylic acid anhydride, the carboxylic acid and at least one organic promoter selected from at least one of the following structural forms (I), (II) and (III): in which R1˜R5 can be the same or different and are independently selected from the group consisting of hydrogen atom, C 1-12 alkyl group, C 3-12 cycloalkyl group, C 6-20 aryl group, C 7-20 alkylaryl group, C 7-20 arylalkyl group, hydroxyl group, C 1-12 hydroxyalkyl group (—R—OH), carboxyl group, C 2-12 carboxyalkyl group (—R—COOH), C 2-12 alkoxyformyl group (—CO—OR), C 1-12 alkylacyloxy group (—O—CO—R), C 1-12 aminoformyl group (—CO—NRR′), C 1-12 alkylamido group (—NR—CO—R) C 1-12 alkylamino group (—N—RR′), C 2-12 cycloalkylamino group, C 1-12 aminoalkyl group (—R—NRR′), C 4-12 cycloaminoalkyl group, C 2-12 alkylacyl group (—CO—R), C 1-12 cycloalkylacyl group, C 1-12 amidoalkyl group (—R—CO—NRR′), C 1-12 imido group (—N(CO—R) 2 ), C 1-12 imidoalkyl group (—R—N(CO—R) 2 ), C 1-12 alkoxy group (—O—R), C 1-12 cycloalkoxy group, C 1-12 amino acid alkyl group, and R1 and R2 can be coupled to form an aromatic ring, a heteroaromatic ring or a non-aromatic ring, provided that in the structural forms (I) and (III), R1˜R5 are not a hydrogen atom at the same time and in the structural form (I), when R1, R2 and R4 are a hydrogen atom, R3 is not a methyl group.