process for the production of c8 to c12 alpha, omega - dicarbonsaeuren

摘要

Straight-chain a - o -dicarboxylic acids with 8 to 12 carbon atoms are prepared by oxidising C8-C12 cyclic alcohols or ketones with nitric acid in the presence of an ammonium vanadate/copper catalyst. The nitric acid concentration is maintained at 50-70%, and the products are filtered from the mixture at 35-90 DEG C., and at least a portion of the filtrate is recycled. The feedstock may be a mixture of alcohols and ketones obtained by the air oxidation of cyclodecane or cyclooctane, and the oxidation is preferably in an aqueous slurry. A two-stage process with oxidation and filtration in separate stages is preferred, and examples are given.