Magnesioaluminophosphate molecular sieves with ATS topology: Synthesis by dry-gel conversion method and catalytic properties in the isopropylation of biphenyl

The selectivity for 4,4′-diisopropylbiphenyl (4,4′-DIPB) was about 30-35% among DIPB isomers in the isopropylation of biphenyl (BP) over MgAPO-36: this value is lower than MOR and other zeolites with straight channels. Because the selectivity of 4,4′-DIPB is higher than the composition in equilibrium, the catalysis is controlled by the pores of MgAPO-36. The relative low selectivity for MgAPO-36 is not due to their pore entrance, but to differences in their pore structure. ATS channel with annular side pocket is too loose for selective formation of the transition state to 4,4′-DIPB, and the formation of bulkier transition states for the other isomers, such as 3,3′- and 3,4′-DIPB, are also allowed inside the channel.