补铝和镁改性β沸石对烷基化反应的影响

EFFECT ON ALKYLATION USING ALUMINUM-REPLENISHED AND MAGNESIUM-MODIFIED ZEOLITE-β

通过加铝盐一次成型方法制得补铝β沸石催化剂样品,根据样品的红外和27Al-MAS-NMR表征结果,讨论了补铝对表面羟基结构的影响和不同状态铝含量的改变。并通过红外测定吸附吡啶和TPD方法对样品进行了各种酸量的测定,结合反应活性评价试验证明了加铝可使催化剂酸量增加并能提高反应活性。结构测定数据表明,补铝样品有较多的微孔表面积和微孔体积。应用浸渍法对加铝样品进行二次Mg2+改性,调节强B酸和B酸的比例。加速失活试验结果表明,只加铝的β沸石样品具有最好的稳定性。

Aluminum replenished zeolite-β samples were prepared by adding aluminum salt in once forming method. Influence of aluminum replenishment on hydroxyl groups and change of the state of aluminum were discussed according to the characterization of 27AL-MAS-NMR and IR. The amounts of different acids in the sample were measured by pyridine adsorption of AR and temperature-programmed desorption, combined with the activity evaluation, it was proved that both the acid amount and the activity increased with aluminum replenishment. The data of structure measurement indicated that the aluminum-replenished samples had more micropore surface and micropore volumes. The aluminum-replenished samples were modified with Mg2+ by impregnation for adjusting the ratio of strong B acid to B acid. The accelerated deactivition indicated that the aluminum-replenished zeolite-β without secondary modification had the best stability.