采用Py-IR分析研究了硼(B)、镁(Mg)及B-Mg复合改性对HZSM-5分子筛表面酸性和催化性能的影响。结果表明,Mg、B及B-Mg复合改性后的HZSM-5,其B酸中心和L酸中心均降低。B元素的加入有利于对位选择性的提高,但会降低催化剂的稳定性。Mg元素的加入减缓了B元素的流失,提高了催化剂的稳定性,从而使得甲苯甲醇烷基化反应中对-二甲苯的收率大大提高。
The effects of B, Mg and B-Mg modifications on the surface acidity and the catalytic performance of HZSM-5 were studied by Py-IR. The modification on HZSM-5 by Mg and B could reduce the Broensted and Louis acid sites. The addition of B increased the selectivity of p-xylene, but decreased the stability. The addition of Mg increased the stability of B-HZSM-5, and the yield of p-xylene increased.