| This paper dealt with the catalyst for benzene methylation with methanol, mainly discusses the application of acid soaking, alkali treatment on ZSM-5 zeolite catalysts. Combined with BET, XRD, NH3-TPD, the modified catalysts were characterized. The physicochemical properties and catalytic performance of catalyst were correlated and discussed. The results show that:the acidity, acid strength, pore structure, specific surface area of ZSM-5 zeolite can influence performances of catalysts notably.Through HCl and Pt composite modified, the selectivity of TX increased to nearly 90%, when the concentration of HCl was 1%, the selectivity of TX reached the highest value of 90.33%. Phosphosic acid dopping after modification, the selectivity of TX increased significantly, reaching 89.3%.When the catalyst is modified, the conversion rate of the catalyst increase significantly, reached 50%. Among them, the benzene conversion of the catalyst treated by phosphate catalyst, NaOH reached 52.6%, higher than that of the nearly 14 percentage points formerly. Selective toluene decreases obviously, is about 55%, and xylene selectivity increased significantly, is about 33%.Ethylbenzene selectivity decreases obviously, trimethyl benzene selective increase slightly. After further loading MgO, the conversion of benzene decreased, while the selectivity of TX obviously increased.Through the study of phosphate concentrations showed that the effect of the concentration of phosphoric acid is not great. The conversion of the catalyst modified by 1.5 mol/L phosphate is 52.6%, and the selectivity of TX is nearly 90%. Loading MgO will decrease the benzene conversion, but is conducive to increase in toluene and xylene selectivity, conversion of ZSM-5 molecular sieve 2.0 mol/L phosphate processing rate of benzene was 47.80%, the selectivity of TX reached 90.30%. It has good value in development. |
