The effect of the solvent on reaction velocity. III.-The interaction of persulphate ions and iodide ions

Abstract

Although in homogenous bimolecular gaseous reactions, the constants A and B of the empirical equation of Arrhenius, k = Be -A/RT , have now a precise meaning, their exact significance for reactions occurring in solution is still doubtful. Inspection of the results obtained by various workers shows that changes of solvent may cause, for any one reaction, very marked changes in B so that, although in certain cases B is the same for the reaction in solution as for the reaction in the gaseous state, it appears necessary to conclude that, in general, this constant embodies factors which are dependent on the solvent environment. The considerable changes in B on change of solvent are shown for three reactions in Table I. Values of RT ln B have been calculated for the interaction of dimethyl aniline and methyl iodide, for bromoacetophenone and aniline, and for pyridine and allyl bromide.