HY/MCM-41包覆型复合分子筛的合成及其在二甲酚加氢脱甲基反应中的催化性能研究

Synthesis of MCM-41 coated HY composite molecular sieve and its catalytic property in hydrodemethylation of xylenol

用HY沸石溶解的硅铝合成出HY/MCM-41包覆型复合分子筛。考察了HY添加量、体系p H、晶化时间对其合成的影响。利用XRD、SEM、N_(2)吸附-脱附、NH_(3)-TPD等对样品进行表征。以3,4-二甲酚为模型化合物,对负载TiO_(2)的HY/MCM-41催化剂加氢脱甲基性能进行评价。结果表明,TiO_(2)/YM-c复合催化剂特殊的孔道结构和酸性质的协同作用在3,4-二甲酚加氢脱甲基反应中表现出较好的催化性能。3,4-二甲酚转化率及苯酚和间甲酚的选择性分别为50.82%、62.17%和36.32%。

HY/MCM-41 coated composite molecular sieve is synthesized by using silica-alumina dissolved from HY zeolite as the"nutrient"substance for synthesizing MCM-41.Effects of the addition amount of HY,p H value of the system,and the crystallization time on the synthesis are investigated.XRD,SEM,N_(2) adsorption-desorption,and NH_(3)-TPD characterization methods are utilized to characterize the samples.Taking 3,4-xylenol as a model compound,the catalytic performance of HY/MCM-41 catalyst supported TiO_(2) in the hydrodemethylation reaction is evaluated.It is shown that TiO_(2)/YM-c composite catalyst exhibits better catalytic performance and stability in the hydrodemethylation reaction of3,4-xylenol due to the synergistic effect between special pore structure and acid properties of the catalyst,and the conversion of 3,4-xylenol,and the selectivity to phenol and m-cresol is 50.82%,62.17%and 36.32%,respectively.