Patent ID: 7253316

Claim:
A process for the joint preparation of (i) formic acid (III); (ii) a carboxylic acid having at least two carbon atoms (II) and/or derivatives thereof; and (iii) a carboxylic anhydride (VII); said process comprising: (a) transesterifying a formic ester (I) with a carboxylic acid having at least two carbon atoms (II) to form formic acid (III) and the corresponding carboxylic ester (IV); (b) carbonylating at least part of the carboxylic ester (IV) formed in step (a) to form the corresponding carboxylic anhydride (V); and (c) transanhydriding at least part of the carboxylic anhydride (V) formed in step (b) with a carboxylic acid (VI) to form a carboxylic anhydride (VII) and the carboxylic acid (II).