Catalysts for the Hydroalkylation of Benzene, Toluene and Xylenes

• Published in: Chemical & pharmaceutical bulletin Vol. 29; no. 1; pp. 15 - 24
• Main Authors: KAMIYAMA, TSUTOMU, ENOMOTO, SABURO, INOUE, MASAMI
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 01.01.1981; Japan Science and Technology Agency
• Subjects: bicyclohexyl
• DOI: 10.1248/cpb.29.15
• ISSN: 0009-2363

The catalytic hydroalkylation of benzene over palladium and fused salt (NaCl-AlCl3) was examined under hydrogen pressure. The combination catalyst of palladium and fused salt showed good activity for hydroalkylation, providing cyclohexylbenzene as the main product, with a small amount of bicyclohexyl. With 0.24% palladium supported on alumina, suitable reaction conditions were : a temperature of 120-140°, and a reaction time of 5-10 hr in the presence of fused salt (NaCl-AlCl3 ; molar ratio 1 : 1). Under these conditions, the yields of cyclohexylbenzene and bicyclohexyl were 54.7 and 5.1%, respectively. This catalyst system was applied to the hydroalkylation of toluene, xylenes and trimethylbenzenes. Based on the behavior of the fused salt, we suggest that NaAlCl4 represents an active species in the hydroalkylation reaction.