Ring-expansion of methylcyclopentane to cyclohexane and ring-contraction of cyclohexane to methylcyclopentane on silica-supported 12-tungstophosphoric acid and stoichiometric and nonstoichiometric microporous silver 12-tungstophosphate

Methylcyclopentane is ring-expanded to cyclohexane and cyclohexane is ring- contracted to methylcyclopentane on 12-tungstophosphoric acid (HPW) support ed on silica and on stoichiometric microporous silver 12-tungstophosphate. The conversions of the two reactants increase with the loading of HPW on Si O2 while achieving significantly higher values on silver 12-tungstophosphat e which pass through a maximum as the Ag/H+ preparative ratio increases. Th e ring-expansion and ring-contraction processes on the supported HPW and th e microporous AgPW are catalyzed by the acidic protons in the solid acid an d the residual protons in the silver salt.