| 摘要 |
PURPOSE:To prepare p-xylene in high conversion and selectivity, by the gas-phase methylation of toluene in the presence of H2 using a catalyst comprising Mg and/or its oxide and Pt-modified crystalline aluminosilicate zeolite. CONSTITUTION:p-Xylene is prepared by the gas-phase methylation of toluene with a methylating agent (e.g. methanol) in the presence of hydrogen using a catalyst comprising Mg and/or its oxide and a Pt-modified crystalline aluminosilicate zeolite. The catalyst contains 1-40wt% of Mg and/or its oxide (as Mg) and 0.01-5wt% of Pt, and has a molar ratio of SiO2/Al2O3 of at least 10. The catalyst is resistant to activity lowering, effective at a small amount, has a relatively larger weight- space velocity, and is industrially advantageous. A highly cocentrated xylene mixture containing >=80% of p-xylene can be obtained by this process. |
