A series of HZSM-5 zeolite catalysts modified with metal oxides (MgO, CaO, SrO, BaO, ZnO, La2O3, and CeO2) were prepared by impregnation method and characterized by XRD, TPD, and N2-adsorption. Methylation of 4-methylbiphenyl (4-MBP) with methanol to 4,4′-dimethylbiphenyl (4,4′-DMBP) was carried out over the prepared catalysts under fixed-bed down-flow conditions. The MgO-modified HZSM-5 could significantly improve the selectivity for target product 4,4′-DMBP. The effects of metal oxides on 4 ,4′-DMBP selectivity were MgO > SrO ≈ ZnO ≈ CaO ≈ La2O3 > BaO, CeO2. During 4-MBP conversion, proper MgO loading could be more effective, and the ion-exchange method was much better than the impregnation method. The high selectivity over HZSM-5 modified with MgO largely resulted from the depression of 4,4′-DMBP second reactions, e.g., isomerization, dealkylation, and alkylation.
|Original language||English (US)|
|Number of pages||5|
|Journal||Chinese Journal of Catalysis|
|State||Published - Dec 1 2003|
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