硼改性对Hβ沸石表面酸性及丙烯与异丙醇醚化反应性能的影响

EFFECT OF BORON MODIFICATON ON SURFACE ACIDITY OF Hβ ZEOLITE AND PERFORMANCE OF PROPYLENE ETHERIFICATION

研究了硼改性的Ｈβ沸石表面酸性变化及其对丙烯与异丙醇醚化反应性能的影响。样品Ｂ＿２Ｏ＿３－Ｈβ的酸量随Ｈ＿２Ｏ＿３含量增加而增多。含量超过３％时酸量基本不变；对于Ｂ＿２Ｏ＿３－Ｈβ－Ａｌ＿２Ｏ＿３催化剂，Ｂ＿２Ｏ＿３使总酸量明显增大，并以Ｌ酸中心增加为主；Ａｌ＿２Ｏ＿３粘合剂的存在促进了Ｂ＿２Ｏ＿３与Ｈβ沸石间的相互作用；丙烯转化率及水的产率分别与Ｌ酸和Ｂ酸中心有很好的对应关系。丙烯与异丙醇的醚化反应主要在Ｌ酸中心上进行。

The effect of B_2O_3 modification,which causes the change of surface acidity onHβ zeoiite, and the performance of etherification of propylene with isoproanol to isopropylether are studied in this paper. Some interesting results have been obtained as follows :( 1)the acid amount of B_2O_3-Hβ catalyst is increased with the increasing B_2O_3 composition andbecomes a constant when B_2O_3 composition is greater than 3%.(2 ) The addition of B_2O_3greatly enhances the total acid amount on B_2O_3-Hβ,Al_2O_3 catalyst, especially the L acidsite,(3) The strong interaction between B_2O_3 and Hβ zeolite caused by Al_2O_3 has been re-vealed by using XPS.(4) The corresponding relation between propylene conversion to L acidsites and H_2O yield to B acid sites dctmonstrates that propylene etherification occurs mainlyon L acid sites and isopropanol dehydration on B acid sites.