Synthesis of high-silica [Al]-SSZ-31 by a steam-assisted conversion methodand its catalytic performance in the isopropylation of biphenyl

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 biphen yl with propylene. In the case of the small-scale synthesis, the product ph ase was found to be dependent on the alkali concentration of the initial ge l, and a phase change from BEA to SSZ-31 to MFI was observed with time at t he 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 te mperature was changed from 150 degreesC to 175 degreesC. [Al] SSZ-31 was ac tive in the isopropylation of biphenyl and selectively catalyzed the produc tion of the least bulky isomers. Biphenyl conversion decreased with increas ing silica to alumina ratio while selectivity remained nearly constant. Tri isopropyl isomer yields were high in the case of lower silica to alumina ra tios.