Characterization and catalytic application of MnCl2 modified HZSM-5 zeolites in synthesis of aromatics from syngas via dimethyl ether

The conversion of syngas to aromatics via dimethyl ether was investigated over MnCl2 modified HZSM-5 zeolites. The results demonstrated that 2%MnCl2 modified HZSM-5 (SiO2/Al2O3 = 38) exhibited higher p-xylene selectivity than other catalysts and further decreased 1,2,4,5-tetramethylbenzene selectivity. The CO conversion was obviously increased after 5%MnCl2 modification to HZSM-5. The catalysts were characterized by XRD, BET, XPS, FT-IR, NH3-TPD, SEM, element analysis and O-2-TPO. The loading amount of MnCl2 affected the adsorption and reaction of DME molecules on zeolites. Appropriate amount of MnCl2 introduction could adjust the acidity and pore volume of HZSM-5 to increase p-xylene selectivity and CO conversion. (C) 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.