Beta分子筛晶种法合成及其加氢脱氧性能

Seed-directed Synthesis of Zeolite Beta and Its Catalytic Properties for Hydrodeoxygenation of Anisole

采用晶种法制备一系列Beta分子筛,考察了晶化温度和时间等因素对合成Beta分子筛的影响,并采用XRD、 XRF、 SEM、 N_2物理吸附、 TG-DSC等手段对产物进行表征,结果显示合成的Beta分子筛具有良好的结晶度、孔道结构、热稳定性和相近的硅铝比;通过对初始凝胶进行老化处理可加快Beta分子筛的晶化速率,产物晶粒尺寸变小、比表面积和孔容变大;在晶种-凝胶体系中加入少量有机模板剂, Beta分子筛的收率和热稳定性均有提升. NH_3-TPD和Pyridine-FTIR分析结果表明不存在有机模板剂的晶种-凝胶体系中合成的Beta分子筛催化剂有更多的总酸量和Br?nsted酸的数量,使其在苯甲醚加氢脱氧反应中表现出高活性和环己烷选择性.

The seed-directed synthesis of zeolite Beta were successfully synthesized and characterized using a wide range of characterization techniques such as XRD,XRF,SEM,TG-DSC and BET.These as-synthesized zeolite Beta samples from different initial reactant gels have similar relative crystallinity,Si/Al ratios and thermal stability.The effect of synthesis conditions such as crystallization temperature,crystallization time,impurity of MOR zeolite and the composition of initial reactant gel were investigated in detail.It is found that aging treatment or introduce low content of TEAOH to the initial reactant gel could accelerate the crystallization rate,and obtain Beta zeolites with smaller average crystal size,larger surface area and more micro pores.It is also found that the yield and thermal stability of zeolite Beta were improved when a small amount of TEAOH was added.NH3-TPD and pyridine-IR results indicate that zeolite Beta synthesized in the absence of TEOAH possess abundant acidic sites,in particular Br?nsted sites,and show good catalytic properties as catalysts for the hydrodeoxygenation of anisole to a range of hydrocarbons,such as cyclohexane and toluene.