Kinetics study of selective solvation of electrons in water--dimethyl sulfoxide mixtures

Dimethyl sulfoxide (DMSO) is known to solvate with difficulty anions including the electron and hence the addition of DMSO to a medium increases the anionic reaction rates. An attempt was made to study this effect in mixtures of H2O--DMSO for specific reactions of the solvated electron using the pulse radiolysis technique. To begin with we chose different solutes among those known as good scavengers of electrons, neutral ones, N2O, and positive and negative ionic ones (NO3- and H+). The experiments were carried out with a Febetron delivering 10-nsec pulses of 1.8-MeV electrons. The rate of disappearance of the solvated electron formed by the pulse was measured by direct observation of the decay absorption at 870 or 600 nm. The ultrapure products were used as supplied except for DMSO which was distilled before use