UDCaT-4: a novel mesoporous superacid catalyst in the selective synthesis of 4,4′-diisopropylbiphenyl by the isopropylation of biphenyl

A novel superacidic mesoporous catalyst UDCaT-4 was developed in this laboratory, which has been used in the alkylation of biphenyl with isopropanol. UDCaT-4 is a synergistic combination of persulfated alumina and zirconia with hexagonal mesoporous silica. 4,4′-Diisopropylbiphenyl (DIPB) has been increasingly used as an intermediate for manufacturing polymers and films possessing high heat resistance and strength. A variety of solid acid catalysts, especially zeolites, are reported for the alkylation of biphenyl to make DIPB but all of them e.g. mordenites, ZSM-5, H-β etc. suffer from coke formation and require regeneration within a few hours of time-on-stream. We report the efficacy of UDCaT-4, which exhibits tremendous stability, activity and selectivity in the vapor phase isopropylation of biphenyl with isopropanol to DIPB. A systematic investigation of the effects of various operating parameters is done. Furthermore, a mathematical model is developed to describe the reaction kinetics which is validated with experimental results.