Abstract
Synthesis of high-silica [Al]-SSZ-31 zeolite by a dry-gel conversion method was performed and the catalyst was tested for the isopropylation of biphenyl with propylene. In the case of the small-scale synthesis, the product phase was found to be dependent on the alkali concentration of the initial gel, and a phase change from BEA to SSZ-31 to MFI was observed with time at the optimum alkali concentration. In the case of the large-scale synthesis, temperature had a profound effect on the crystallization of SSZ-31. A phase transformation from BEA to SSZ-31 was observed when the crystallization temperature was changed from 150 °C to 175 °C. [Al]-SSZ-31 was active in the isopropylation of biphenyl and selectively catalyzed the production of the least bulky isomers. Biphenyl conversion decreased with increasing silica to alumina ratio while selectivity remained nearly constant. Triisopropyl isomer yields were high in the case of lower silica to alumina ratios.