Salt effects on the rates of protonation of amides

Abstract

The rates of protonation of three NN-dimethylamides have been measured in various electrolyte solutions using n.m.r. line broadening techniques. Activity coefficients of the amides in the electrolyte solutions have also been determined. The protonation rates increase rapidly with increasing electrolyte concentration. The results are discussed in relation to the behaviour of other acid catalysed reactions involving protonated intermediates. A comparison of the results in Li⁺ solutions with those of the other alkali metals provides some evidence to support recent reports of strong interactions between Li⁺ and various amides.