ELECTRON-ATTACHMENT TO TOLUENE IN N-HEXANE AND 2,2-DIMETHYLBUTANE AT HIGH-PRESSURE

The effect of dilute concentrations of toluene on the electron mobility in two isomeric hexanes was studied as a function of pressure from 1 bar to 3 kbar and at selected temperatures between 9 and 60-degrees-C. The effect of toluene on the mobility is small at 1 bar but quite large at the higher pressures. The results are interpreted in terms of reversible electron attachment to a toluene species which is the monomer in n-hexane. For this reaction DELTAH(r) is -12.0 kcal/mol in n-hexane at 2.5 kbar. In 2,2-dimethylbutane attachment to a dimeric species is indicated. The volume changes for these attachment reactions are large, between -80 and -100 cm3/mol. In hexane the volume changes are attributed in part to the electrostriction of the solvent by the toluene anion and in part to a positive molar volume of the electron.