Modified Zeolites as Catalysts of Side-chain Alkylation of Aromatic Compounds

摘要

Toluene methylation producing styrene and ethylbenzene is known from the mid-60s.' X-type zeolites containing potassium, rubidium or cesium cations were used in this reaction. The side-chain alkylation of toluene was shown to proceed on basic sites via a radical mechanism2'3 and the size of introduced cations affects significantly the catalytic properties.4 Conditions of exchange cation introduction are of great importance for efficient catalyst synthesis. Thus, cesium introduction under standard conditions yields a catalyst providing a 1.2-4.2 % yield of styrene.5 To increase the styrene yield, one can modify the catalyst with different additives though it can result in a rapid coke deposition,6 Here to define catalytic properties of zeolites modified under hydrothermal conditions.