PROTON SOLVATION IN METHANOL SOLUTIONS OF HCL

The MFTIR IR spectra of solutions of HCl in methanol were obtained in the 900-4000 cm-1 frequency range. It was found that each proton binds two molecules of methanol. The spectra exhibit intense, continuous ab sorption (CA) with an intensity coefficient at 2000 cm-1 of 174 +/- 10 liter/(mole.cm), which is in agreement with the corresponding coeffic ient for H5O2+. The optical densities of CA are linear functions of th e concentration of HCI at 900-1600 cm-1; there is no linearity at high er frequencies for C(HCl) > 4 M, and there are less than two molecules of MeOH for each (MeOH)2H+ ion. The results obtained are in agreement with the model in which CA arises in solutions of strong acids becaus e of the interaction of proton vibrations in a strong symmetric H bond with the vibrations of other groups of the proton disolvate.