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以4 甲基联苯(4 MBP)与甲醇的烷基化反应为探针,在固定床反应器上考察了不同类型的沸石及不同n(SiO2)/n(Al2O3)的HZSM 5的催化性能。以氢型ZSM 5(n(SiO2)/n(Al2O3)=80)为母体,分别用磷酸氢二铵(AHP)和三苯基膦(TPP)为改性剂,采用浸渍法制备了一系列不同磷担载量的HZSM 5,用XRD、TPD和氮气低温物理吸附等手段对其进行了表征,考察磷担载量对甲基化性能的影响。结果表明,Hβ、HM、Y等具有十二元孔的沸石作为催化剂时,产物中几乎包括了所有的异构体,目的产物4,4’ 二甲基联苯(4,4’ DMBP)的选择性很低。而以HZSM 5为催化剂,4,4’ DMBP有一定的选择性;随着n(SiO2)/n(Al2O3)的增加,4 MBP转化率降低,4,4’ DMBP选择性增加。磷改性可以显著提高4,4’ DMBP的选择性。
The catalytic properties of different types of zeolites and HZSM 5 with different n (SiO 2) / n (Al 2 O 3) were investigated on a fixed bed reactor using alkylation of 4-methyl biphenyl (4 MBP) and methanol as probes . Hydrogenated ZSM 5 (n (SiO 2) / n (Al 2 O 3) = 80) was used as matrix to prepare a series of catalysts with diammonium hydrogen phosphate (AHP) and triphenylphosphine (TPP) HZSM 5 with different phosphorus loadings was characterized by XRD, TPD and low temperature physisorption of nitrogen, and the effect of phosphorus loading on the methylation performance was investigated. The results showed that zeolites with twelve-membered pores, such as Hβ, HM and Y, contained almost all of the isomers in the product. The target product, 4,4’-dimethylbiphenyl (4,4’-DMBP) Very low selectivity. 4,4’-DMBP has a certain selectivity to HZSM 5 as a catalyst. With the increase of n (SiO 2) / n (Al 2 O 3), the conversion of 4 MBP decreases and the selectivity of 4,4’-DMBP increases. Phosphorus modification can significantly increase 4,4 ’DMBP selectivity.