The effects of SiO2/Al2O3, MgO modification and hydrothermal treatment on methylation of 4-methylbiphenyl (4-MBP) into 4,4′-dimethylbiphenyl (4,4′-DMBP) with methanol over ZSM-5 under fixed-bed down-flow conditions were investigated and the results show that with an increase in the SiO2/Al2O3 (from 50 to 150, molar ratio), the selectivity to 4,4′-DMBP increases from 25% to 79%. MgO modification enhances the selectivity to 4,4′-DMBP, but lowers catalyst activity and leads to the rapid deactivation. Hydrothermal treatment not only increases the selectivity, but also improves the stability. When CBV1502 (SiO2/Al2O3 = 150) catalyst was hydrothermally treated at 500°C, the selectivity to 4,4′-DMBP can increase up to 85%. The selectivity to 4,4′-DMBP was further improved to about 90% by the increasing in the amount of mesitylene as solvent on the feed.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry