| 摘要 |
Carboxylic acid anhydrides of the general formula R-CO-O-CO-R'(I) in which R and R' are identical or different and represent an optionally substituted alkyl group having 1 to 18 carbon atoms, an optionally substituted cycloalkyl group having 3 to 12 carbon atoms or an optionally substituted aryl group, or represent an optionally substituted 5-membered or 6-membered heterocyclic radical which additionally can be fused to a benzene ring, are obtained in high yields by a process in which a trimethylsilyl carboxylate of the general formula R-CO-OSi(CH3)3 (II) in which R has the meaning given above, is reacted with a carboxylic acid-halide of the general formula R'CO-X (III) in which R' has the meaning given above, and X represents a halogen atom, if appropriate in the presence of a catalyst and, if appropriate, in the presence of a diluent, at a temperature between 20 DEG and 250 DEG C. The carboxylic acid anhydrides are valuable intermediate products for organic syntheses. They can be used, for example, for the preparation of certain herbicidally active compounds.
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