HZSM-23/γ-Al_2O_3丁烯异构化催化剂的活性和表面酸性

Catalytic Activity and Surface Acidity of HZSM 23/γ Al 2O 3 Catalyst for Isomerization of n Butene to Isobutene

研究了ＨＺＳＭ－２３分子筛和γ－Ａｌ２Ｏ３配比对ＨＺＳＭ－２３／γ－Ａｌ２Ｏ３改性分子筛催化正丁烯异构化反应的转化率和选择性的影响．在中温及低空速条件下，随着配比中γ－Ａｌ２Ｏ３的增加，转化率降低而选择性有所提高．ＸＲＤ．ＴＰＤ及ＦＴ－ＩＲ对催化剂进行表征的结果显示：经改性后的ＨＺＳＭ－２３的总酸量和强酸位减少，而Ｌ酸的浓度增加，正丁烯异构化反应的选择性主要取决于Ｌ酸位浓度．

The effect of ratio between HZSM 23 and γ Al 2O 3 on conversion and selectivity of promoted HZSM 23/γ Al 2O 3 catalyst for isomerization of n butylene has been studied. The valuations of activity show that reducing conversion and enhancing some selectivity are accompanied with increasing the content of γ Al 2O 3 in HZSM 23/γ Al 2O 3 catalyst under the moderate reaction temperature and the lower flowing rate of feed. Characterizations of catalyst by XRD,TPD and FT IR showed that both total acidity and strong acid sites of the promoted catalysts were decreased but the concentration of L acid was increased. The selectivity for isomerization of n butene to isobutene is mainly dependent on the concentration of L acid.