Self-diffusion and conduction in hydrogen-bonded solids. Part 1.—Labile proton diffusion in pivalic acid

Abstract

A study has been made of the self-diffusion of labile protons in the plastic phase of pivalic acid using (CH₃)₃·C·COO³H as the tracer. The carboxyl protons diffuse approximately 10³ times more rapidly than the molecules and with a significantly different activation energy. Both differences are confirmed by high-resolution n.m.r. measurements. Conductimetric measurements show that the proton migration is not accompanied by an equivalent charge transport. This leads to the conclusion that the proton migrates via an exchange mechanism which involves molecular rotation.