摘要
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 effects of zeolite type, the SiO2/Al2O3 mol ratio of HZSM-5 on the methylation of (4-methylbiphenyl) (4-MBP) with methanol were investigated by using a fixed-bed down-flow reactor. The results showed that the products of methylation of 4-methylbiphenyl (4-MBP) with methanol catalyzed by zeolites with 12-membered ring, such as HY, HM and Hβ, yielded all the possible isomers, no selectivity of the target product 4,4'-dimethylbiphenyl ((4,4'-DMBP) )was observed.The 10-membered ring zeolite ZSM-5 catalyst showed moderate selectivity to 4,4'-DMBP. The conversion of 4-MBP decreased and the selectivity to 4,4'-DMBP increased with an increase of the SiO2/Al2O3 mol ratio of ZSM-5. With HZSM-5 (n(SiO2)/(n(Al2O3)=80) )as the precursor, HZSM-5 zeolites with different phosphorus loading were prepared by impregnation method modified with ammonium hydrogen phosphate (AHP) and tri-phenyl phosphine (TPP), respectively.The prepared samples were characterized by XRD, TPD, N2 low-temperature physical adsorption and evaluated with methylation of 4-MBP with methanol.The results showed that both inorganic and organic phosphorus modification greatly improved the selectivity to 4,4'-DMBP.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2004年第3期37-42,共6页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
教育部留学回国人员科研启动基金资助项目(教外司留[2003]14号)
