Electron behavior in mixed solvents: optical spectra and reactivities in water/alkane diols

Open Access
Publisher Website
Google Scholar
Abstract
Investigation of the effect of solvent structure on the optical absorption spectrum and reactivity of solvated electrons has been extended to diol/water mixed solvents, using 1,2-ethanediol (12ED) and 1,4-butanediol (14BD). The large effects that had been found in mono-ol/water mixed solvents did not occur in diol/water. Although addition of 3 mol% of a diol to water increased the optical absorption energies of e−s by 0.06 eV, similar to the shift caused by addition of 3 mol% of a mono-ol, the variation of the spectrum over the rest of the composition range was nearly ideal in diol/water, in contrast to the very non-ideal variation in mono-ol/water. Reaction rate constants kS at 298 K in the diol/water mixed solvents vary approximately as the inverse viscosity,η−1.0, in the diffusion-controlled limit. However, when reactions are two or three orders of magnitude slower than diffusion controlled, kS at 298 K is independent of η. Toluene reacts with e−s at a 10−3-fold smaller rate than does nitrobenzene; the difference is nearly completely due to a ~50 J/mol K lower entropy of activation of the former reaction.

This publication has 0 references indexed in Scilit: