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用改进的快速合成法制备了2个系列的催化剂,并用XRD、N2吸附、FT-IR、27Al MAS、NMR和NH3-TPD等手段对其表征,用环己酮肟气相贝克曼重排反应评价其活性。结果表明,合成的催化剂具有MCM-41的结构,铝和硼进入到分子筛的骨架中。当n(Al)/n(B)的值一定时,随着铝和硼添加量的增多,分子筛的弱酸性位的数量增多,己内酰胺的选择性升高。当添加的铝和硼的总量一定,随着铝含量的减少,相应硼的量增加,己内酰胺的选择性升高。只添加硼时环己酮肟转化率和己内酰胺的选择性均很低。(Al,B)-MCM-41分子筛在气相贝克曼重排反应中的活性主要与骨架中的铝和硼的数量以及弱酸位的数量有关。
Two series of catalysts were prepared by a modified rapid synthesis method. The catalysts were characterized by XRD, N2 adsorption, FT-IR, 27Al MAS, NMR and NH3-TPD. The gas phase Beckmann rearrangement reaction with cyclohexanone oxime Its activity. The results show that the synthesized catalyst has the structure of MCM-41, aluminum and boron into the framework of the molecular sieve. When the value of n (Al) / n (B) is constant, with the increase of the amount of aluminum and boron, the number of weakly acidic sites of the molecular sieve increases and the selectivity of caprolactam increases. When the total amount of aluminum and boron added is constant, as the aluminum content decreases, the amount of boron increases and the selectivity of caprolactam increases. The cyclohexanone oxime conversion and the caprolactam selectivity are very low with boron alone. The activity of (Al, B) -MCM-41 zeolite in gas-phase Beckmann rearrangement reaction is mainly related to the amount of aluminum and boron in the framework and the number of weak acid sites.