Alkylation of resorcinol with tertiary butanol over zeolite catalysts: Shape selectivity vs acidity

The catalytic performance of various zeolites such as H-ZSM-5, H-Y, H-beta, H-Mordenite in resorcinol alkylation with tertiary butanol demonstrated that pore characteristics have major influence on product selectivity, whereas acid strength and number of acid sites influenced resorcinol conversion. The passivation of external surface of H-beta zeolite by silylation and amine poisoning produced shape selectively O-alkylated resorcinol methyl tert butyl ether (RMTBE) and 4-tert butyl resorcinol (4-TBR). We propose that 4-TBR formation goes over external acid sites through RMTBE isomerization, whereas formation of 4-TBR takes place inside the pores through direct C-alkylation mechanism.