Selective zeolite catalyst for alkylation of benzene with ethylene to produce ethylbenzene

Abstract

In this work, a selective catalyst of BXE ALKCAT zeolite has been developed with about 30 % of ZSM-5 balanced with kaolinite, and applied for gas-phase alkylation of benzene (BZ) with ethylene (E). The catalyst has been tested in a fixed-bed down-pass flow reactor under different conditions of temperatures ranging between 300 and 450 °C with BZ to E mole ratios ranging between 1:1, 3:1 and 6:1 under atmospheric pressure and space velocity ranges between 0.1 and 150 h−1. The BXE ALKCAT zeolite catalyst has been characterized using: scanning electron microscope, X-ray diffraction, specific surface area, pore volumes, pore size distributions, X-ray photoelectron spectroscopy, and differential thermal analysis, and thermo-gravimetric analyses. Ethylbenzene was the main product of alkylation, and diethylbenzene isomers (ortho-, meta-, and para-) were the minor products. In the case of 1:1 mol ratio of BZ to E, the selectivity of EB about 85.5 % at highest conversion of BZ was obtained after 1 h of reaction on stream at 450 °C. A decrease in the temperature to 300 °C (with 1:1 mol ratio) caused the selectivity of EB to decrease to 73.0 %. EB and DEBs yields were found to increase with increasing the reaction temperature and decreasing the mole ratio of BZ to E. The conversion of BZ appeared to be depending strongly on mole ratio of BZ to E at a given temperature. The study has shown that the BXE ALKCAT zeolite is active as a catalyst for the alkylation reaction and selective to EB compared with other zeolite catalysts.