摘要
以四丙基氨为微孔模版剂, 阳离子高分子聚合物为介孔模版剂, 合成了具有多级介孔的ZSM-5分子筛, 并用于甲醇气相脱水合成二甲醚. 结果表明, 加入阳离子高分子聚合物后, 合成的HZSM-5分子筛样品既保持了其MFI典型结构, 又呈现了多级介孔特征; 随着阳离子高分子聚合物模板剂加入量的增加, 其多级介孔特征更为明显. 具有多级介孔的HZSM-5分子筛表现出比常规微孔HZSM-5分子筛高的反应稳定性和二甲醚选择性, 这主要是由于其织构和酸性的双重作用.
Hierarchical mesoporous ZSM‐5 zeolites were synthesized using small organic cations of tetrapropylammonium and meso‐sized cationic polymers of dimethyldiallyl ammonium chloride acrylamide copolymer as templates.The zeolites were used for the dehydration of methanol to dimethyl ether(DME).Characterization results showed that the basic MFI‐type structure was still obtained after adding the cationic polymers,while their nitrogen isotherms exhibited a broad hysteresis loop at relative pressures higher than 0.4,which proved the presence of mesopores.The mesoporosity of the hierarchical mesoporous ZSM‐5 can be adjusted simply by adding different amounts of the cationic polymer.Catalytic tests showed that the hierarchical mesoporous HZSM‐5 zeolites exhibited better stability than conventional HZSM‐5 and excellent DME selectivity.The activity for methanol dehydration strongly depended on the textural property and acidity of the catalyst.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第8期1576-1582,共7页
基金
supported by the National Basic Research Program of China (973 Program,2007CB210207,2013CB228104)
the High Technology Research and Development Program of China (863 Program,2007AA05Z415)~~
关键词
多级孔
HZSM-5分子筛
表面酸性
甲醇脱水
二甲醚
Hierarchical mesopore HZSM‐5 zeolite Surface acidity Methanol dehydration Dimethyl ether