Formation of a carboxyl group satellite line in the n.m.r. spectra of solid carboxylic acids

The structural factors resulting in the formation of the carboxyl group satellite line on the low field side of the 1 H n.m.r. spectra of carboxylic acids in the solid state have been determined from the temperature dependences of the carboxyl proton chemical shifts of acetic, dimethylacetic, ethylacetic, phenylacetic, benzoic, o ‐methylbenzoic, p ‐methylbenzoic and adamantyl carboxylic acids. The carboxyl group low field satellite forms at temperatures near the melting point only in the case of carboxylic acids with bulky hydrocarbon radicals ( o ‐methylbenzoic and adamantyl carboxylic acids).