摘要
采用浸渍法对Hβ分子筛进行磷改性 ,用NH3-TPD和IR表征了催化剂的表面酸性质 ,以苯与丙烯烷基化反应考察了Hβ沸石改性前后的选择性和稳定性。结果表明 :磷使强酸受到抑制 ,正丙苯的含量较Hβ分子筛有显著下降 ,多异丙苯生成量有所降低 ,从而提高了Hβ催化剂的选择性 ;总酸量与母体Hβ分子筛比较有所下降 ,但磷质量分数不能过高 ,当磷质量分数在 2 %时 ,B酸中心和L酸中心都显著减少 ,总酸量显著减少 ,致使催化剂的活性和稳定性显著下降 ;在相同条件下 。
Hβ zeolite was modified with phosphorus by means of impregnation. The surface acidity of the modified catalysts was characterized with NH_3-TPD and FTIR. The catalytic performance of the modified zeolites for benzene alkylation with propylene was also studied. The results show that the modification of Hβ zeolite by phosphorus suppresses acid strength and also significantly decreases the total amount of acid and the content of n-propylbenzene, and therefore the alkylation selectivity is increased;both B and L acid sites are greatly decreased when phosphorus content is 2 % by weight, the catalytic stability and activity are also decreased, hence the amount of phosphorus added to the zeolite should not be too high; there is no difference for the modification with different phosphorus sources under the same condition.
出处
《石油化工高等学校学报》
CAS
2004年第4期34-37,共4页
Journal of Petrochemical Universities
关键词
HΒ分子筛
烷基化
磷改性
表面酸性
Hβ zeolite
Alkylation
P Modification
Surface acidity
