Ethylation of Benzene over Silica-Alumina Catalyst using Organic Halogen Compounds as Accelerator

Abstract

The vapor phase alkylation of benzene with ethylene over silicaalumina (S. A) catalyst has been studied by a flow method under pressure of 20∼30kg/cm² and within the temperature range of 250∼350°C. By the addition of a small amount of organic halogen compound to the feed, the catalyst showed a remarkably high activity at relatively low temperature and pressure. Among various organic halogen compounds used in the reactions, gem-type halogen compounds, such as carbon tetrachloride, chloroform, trichlorofluoromethane and 1, 1, 1-trichloroethane, served as the accelerators of the reaction, but victype halogen compounds, such as 1, 2-dichloroethane and 1, 2-dichloropropane, decreased the activity of the catalyst.
From an examination of the correlation between the activities and the total acidities of the catalysts, it was found that the activity in the reaction depended upon the acidity of the catalyst. The kinetic study showed that the rate of this reaction was first order with respect to the partial pressure of ethylene and benzene respectively in the initial stage of the reaction, and the apparent activation energy was about 10kcal/mole.