Dimerization of 2-phenylpropene to produce 2,4-diphenyl-4-methyl-1-penteneover H-Y zeolite

Dimerization of 2-phenylpropene using H-Y zeolite in the presence of diethy lcarbonate (co-catalyst) in a liquid phase gave an industrially important l inear dimer, 2,4-diphenyl-4-methyl-1-pentene (1-PT), as a major product. By the addition of diethylcarbonate, the formation of undesirable products, 2 ,4-diphenyl-4-methyl-2-pentene (2-PT), 1,1,3-trimethyl-3-phenylindan (IND), and trimers, was suppressed with a decrease in the dimerization rate. Neit her Na-Y zeolite nor amorphous silica-alumina Al2O3-SiO2 showed any signifi cant activity for the dimerization. Low reaction temperature favored the fo rmation of 1-PT. The maximum yield of the target product, 1-PT, was obtaine d over the catalyst: 78% yield at 86% conversion under optimum conditions a t 353 . (C) 2000 Elsevier Science B.V. All rights reserved.