A titanosilicate Ti-ECNU-8 with a FER type sub-zeolite structure was developed by pots-synthesis and applied to the epoxdiation of alkenes with hydrogen peroxide.A controlled acid treatment on the pure silica layered precursor PLS-3 of FER topology gave rise to a sub-zeolite ECNU-8.Composed of a collection of FER sheets without an ordered stacking manner along layer related[100]direction,the structure of ECNU-8 was constructed by a reorientation of interlayer hydrogen bond moieties caused by partial removal of interlayer organic structure directing agent.ECNU-8 possessed an external surface area enlarged by ca.30% in comparison to corresponding three-dimensional FER zeolite.Through a solid-gas reaction with TiCl4 vapor,tetrahedral Ti active sites were introduced into the framework.The resultant Ti-ECNU-8 retained the structural properties of ECNU-8,and exhibited an excellent catalytic performance for the epoxidation of cycloalkenes owing to the accessible Ti sites located in open reaction space.
采用常规水热法合成SAPO-11和ZSM-22分子筛,制备分别含有分子筛的催化剂,借助XRD、SEM和NH3-TPD表征2种催化剂的结构和酸性,并以加氢预精制溶剂脱蜡油为原料,采用固定床反应器研究Pt/SAPO-11和Pt/ZSM-22催化剂的加氢异构反应性能.结果表明:催化剂的反应活性和选择性主要取决于催化剂的酸量和酸强度,相对而言,由于SAPO-11分子筛催化剂弱酸含量较高,具有更佳的异构化选择性.利用1 H NMR和13 C NMR核磁共振研究加氢异构反应前后基础油的化学结构变化,Pt/SAPO-11催化剂有较高的加氢异构选择性.
