Ethylation of benzene: Effect of zeolite acidity and structure
Zeolite catalysts based on ZSM-5, TNU-9, SSZ-33 and mordenite were prepared and characterized. The catalytic performance of these zeolites containing channels of different sizes has been studied in benzene ethylation with ethanol at three different reaction temperatures (250, 275 and 300 °C) for reaction times of 3, 5, 7, 10, 13, 15 and 20 s. In the ethylation reaction of benzene with ethanol, SSZ-33 catalyst comprising 12-12-10-ring channels gave the highest benzene conversion, which is the result of high acidity of this zeolite together with increased mass transport through large pores. The conversion of benzene in the ethylation reaction of benzene with ethanol over the different zeolite catalysts follows the order: SSZ-33 > TNU-9 > ZSM-5 > mordenite. TNU-9 catalyst behaves like the 10-ring ZSM-5 with respect to ethylbenzene selectivity, while the behavior of SSZ-33 is close to that of a large pore zeolite with potential cage effects. EB selectivity follows the order: ZSM-5 > TNU-9 > SSZ-33 > mordenite, which implies that this order is not directly related to the benzene conversion. In addition, a simplified kinetic model based on reactant-converted deactivation model was developed for the reaction and compared with the obtained experimental data.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (105 K)Download as PowerPoint slideResearch highlights▶ The conversion of benzene in the ethylation reaction follows the order: SSZ-33 > TNU-9 > ZSM-5 > MOR. ▶ Ethylbenzene selectivity follows the order: ZSM-5 > TNU-9 > SSZ-33 > mordenite. ▶ It can be concluded that acidity plays a major role in toluene formation over these zeolites. ▶ Apparent activation energies for benzene ethylation follow the order: Em1 > EZ1 > ES1 > ETNU-1.
Journal: Applied Catalysis A: General - Volume 385, Issues 1–2, 15 September 2010, Pages 31–45