24-05 461. Chemical Cmtitution and the Dissociation Constants of Monocurboxylic Acib. Part X VII.* ortho-E'ects in Substituted Salicylic Acids.

The monoacetylbenzoic acids display the order of strengths p-> m-> o-> H (in water a t 2 6 ' ) and the fact that the o-isomer is only a little stronger than the parent benzoic acid is interpreted in terms of the view that the acetyl group is less strongly conjugated with the benzene ring than is the carboxyl group. The greater bulks of benzoyl and toluoyl groups, and their stronger conjugative capacities, account for the relatively large enhancements in strength exhibited when these groups enter the ortho-position.THE dissociation constants of five acylbenzoic acids have been determined in water at 25" by the conductivity method (Table 1). The expectation that the groups Ac, Bz, and P-C,H,Me*CO would enhance the strength of benzoic acid when substituted in the benzene

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