PROCESS FOR THE CARBONYLATION OF A CONJUGATED DIENE TO A DICARBOXYLIC ACID

摘要

A process for the carbonylation of a conjugated diene to a dicarboxylic acid, comprising the steps of (a) contacting a conjugated diene with carbon monoxide and water in the presence of a catalyst system including a source of palladium, a source of an anion and a bidentate phosphine ligand, to obtain a mixture comprising an ethylenically unsaturated acid and reversible diene adducts; (b) separating the obtained reaction mixture into a gaseous stream comprising unreacted conjugated diene and carbon monoxide, a first normally liquid stream comprising at least part of the ethylenically unsaturated acid and the reversible diene adducts, and a second normally liquid stream comprising the catalyst system in admixture with the ethylenically unsaturated acid; (c) recycling the second liquid stream obtained in step (b) to step (a) ; (d) separating the first liquid product stream obtained in step (b) into a stream comprising the ethylenically unsaturated acid and a stream comprising the reversible diene adducts; and (e) contacting the stream comprising the ethylenically unsaturated acid obtained in step (d) with carbon monoxide and water in the presence of a second catalyst system including a source of palladium, a source of an anion and a bidentate phosphine ligand.