Methylcyclohexane and methylcyclohexene cracking over zeolite Y catalysts

Naphthenes are an important class of molecules in fluid catalytic cracking. The cracking behavior of the model naphthenes, methylcyclohexane and methylcyclohexene was investigated over rare earth Y and USY zeolite catalysts. Initial products from methylcyclohexane are formed by a combination of protolytic and β-scission cracking plus isomerization, H− transfer, H+ transfer and dehydrogenation reactions. Methylcyclohexane is a sensitive probe for characterizing the chemistry occurring on solid acid surfaces. Methylcyclohexene is the key intermediate in the formation of aromatics from methylcyclohexane. Methylcyclohexene cracks at a slower rate than methylcyclohexane but overall conversion is higher because hydride transfer reactions are fast.