4,4 - bis (carboxyphenylsulfonyl) diphenyl ether, process for their production and their use.

摘要

Novel aromatic carboxylic acids are represented by the general formula [V]: CHEM wherein R1 is hydrogen or a carboxyl group, and R2 and R3, which may be the same or different, are hydrogen, a lower alkyl group containing from 1 to 5 carbon atoms or a carboxyl group; and n is the number of substituents other than hydrogen and is an integer of from 0 to 4; Preferably R1 is hydrogen. The carboxylic acids may be used in producing useful polymers such as polyesters, polyamides and polyimides. The carboxylic acids may be made by a process which comprises the step of oxidizing a compound represented by the general formula [IV]: CHEM wherein R4 is hydrogen or a methyl group; R5 and R6, which may be the same or different, are hydrogen or a lower alkyl group containing from 1 to 5 carbon atoms; and n is the number of substituents other than hydrogen and is an integer of from 0 to 4, with molecular oxygen in a liquid phase in an aliphatic carboxylic acid solvent in the presence of a cobalt-manganese-bromine catalyst.