高岭土为原料合成Y/MCM-41复合分子筛及其催化性能

Preparation and catalytic performance of Y/MCM-41 composite molecular sieve

以高岭土为原料,采用水热法合成了复合分子筛Y/MCM-41.采用X射线粉末衍射和氮气物理吸附等手段进行了表征,研究了各种因素对合成样品结构性能的影响,考察了该分子筛对苯酚与叔丁醇烷基化反应的催化性能.结果表明:120℃下水热反应24 h,成功合成了复合分子筛;复合分子筛具有介孔和微孔双重孔结构,比表面积为628.9 m2.g-1,平均孔径为2.73 nm;复合分子筛对苯酚与叔丁醇的烷基化反应具有良好的催化性能,最佳反应条件为n(叔丁醇)/n(苯酚)=2.0,空速为1.0 h-1,反应时间为1 h,反应温度为140℃,苯酚的转化率可达62.2%,4-叔丁基苯酚的选择性可达86.0%;反应温度对催化性能有明显影响,低温范围内升温有利于烷基化反应的进行,而温度过高时,脱烷基化反应为主要反应.

Composite molecular sieve was hydrothermal synthesized by using kaolin as raw material. The samples were characterized by XRD and N2 physical adsorption, and the effects of various factors on sam-ple textural properties were also discussed. The catalytic performance of the compo-site molecular sieve was investigated by alkylation reaction of phenol and tert-butyl alcohol. The results show that the compo- site molecular sieve with mesoporous and microporous structure was successfully hydrothcrmal synthesized for 24 h at 120 ~Cwith specific surface area of 628.9 m^-2^·g^-1 and average pore size of 2.73 nm. The composite molecular sieve exhibits good catalytic performance for the alkylation reaction of phenol and tea-butyl alcohol. The optimum molar ratio of tert-butanol to phenol is 2.0 at 140 ℃ with reaction time of 1 h and WHSV of 1.0 h^-1, and the conversion of phenol is 62.2% with 4-tert-butyl-phenol（4-TBP） se-lectivity of 86.0%. The reaction temperature has obvious effect on the catalytic performance of composite molecular sieve. The increase of reaction temperature at low temperature range is favorable for the alkyla-tion dominant, while the dealkylation is dominant at high temperature.