氢氧化铌改性沸石分子筛的表面酸性及其催化活性  

Surface Acidity and Catalytic Activity of Nb(OH)_5-modified Zeolite

作　　者：曾拥军[1] 王一男[1] 王昕[1] 施力[1] 

机构地区：[1]华东理工大学石油加工研究所,上海200237

出　　处：《化学世界》2007年第11期641-645,共5页Chemical World

摘　　要：利用吡啶吸附红外光谱(Py-IR)表征了氢氧化铌改性分子筛的表面酸性,用催化法脱除芳烃中微量烯烃的反应研究其酸催化活性。结果表明,氢氧化铌的引入导致催化剂表面Brφnsted酸中心和Lewis酸中心重新分布,总Brφnsted酸量和Lewis酸量都随氢氧化铌含量的增加而减少;强B酸不利于脱烯烃反应;催化剂的活性随总Brφnsted酸量与总Lewis酸量比例的增加而提高,用磷酸或草酸处理氢氧化铌,总Brφnsted酸量与总Lewis酸量的比例增大,可进一步提高分子筛的活性和寿命。The surface acidity of Nb（OH）5-modified zeolite was characterized by FT IR spectra of pyridine absorbed on the surface. Catalytic activity was determined by the catalytic removal of trace olefins from aromatic hydrocarbons. The results showed that the presence of niobium leads to redistribution of Brφnsted and Lewis acid centers, and the acid site density decreases with an increase of niobium weight on catalysts. The strong B acid is unfavorable to the reaction of removal of trace olefins from aromatic hydrocarbons. The activity of catalysts is enhanced with the increase of the ratio of total Brφnsted acid to total Lewis acid. The resuhs obtained also revealed that treatment of Nb（OH）5 with H3PO4 or H2C2O5 increases the ratio of total Brφnsted acid to total Lewis acid, hence both activity and life span of the catalysts could be filrther enhanced .

关 键 词：表面酸性 氢氧化铌 红外光谱 沸石分子筛 烷基化 

分 类 号：O657.33[理学—分析化学]