Differences between Zn/HZSM-5 and Zn/HZSM-11 zeolite catalysts in alkylation of benzene with dimethyl ether

Abstract

HZSM-11 zeolite supported Zn catalysts with different Zn contents (xZn/HZSM-11A) were prepared. In the alkylation of benzene with dimethyl ether (DME) in a fixed bed reactor, the catalyst with Zn content of 6 wt% (6Zn/HZSM-11A) showed appropriate performance. Focus was put on the comparison between 6Zn/HZSM-5 and 6Zn/HZSM-11 with the same crystal size of 600–800 nm, and also with the similar BET surface area, micropore volume, Si/Al2 molar ratio, and acidity. In the alkylation of benzene with DME, the 6Zn/HZSM-11 showed better activity and stability, and especially enhanced the conversion of benzene and selectivities to xylene and trimethylbenzene, compared with the 6Zn/HZSM-5. This was mainly related to the higher adsorption capacity and adsorption-desorption rates to the three adsorbates (benzene, m-xylene and 1,3,5-trimethylbenzene) over the 6Zn/HZSM-11 in comparison with the 6Zn/HZSM-5.