Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (04): 320-326.doi: 10.3866/PKU.WHXB19980407

• ARTICLE • Previous Articles     Next Articles

Structure of Highly Siliceous ZSM-5 Zeolites and Ti-ZSM-5 Zeolites Obtained by Indirect Synthesis

Zhao Qi, Han Xiu-Wen, Liu Xiu-Mei, Liu Xian-Chun, Zhai Run-Sheng, Bao Xin-He, Lin Li-Wu, Guo Xin-Wen, Zhang Fa-Zhi, Wang Xiang-Sheng   

  1. State Key Laboratory of Catalysis,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023|Open Laboratory of Comprehensive Utilization for Carbon Resource,Dalian University of Technology,Dalian 116012
  • Received:1997-07-02 Revised:1997-10-31 Published:1998-04-15
  • Contact: Bao Xin-He

Abstract:

 Solid state NMR with magic angle spinning (MAS) and cross polarization(CP) techniques, and IR spectroscopy have been used to investigate the structural Characterizations of the highly siliceous ZSM-5(S-1) zeolites synthesized using various organic ammoniums or amines as templates and the Ti-ZSM-5 zeolites prepared by the solid reaction of ZSM-5 zeolites with titaniumtetrachloride vapor at 873K . It has been shown that the structure of the ZSM-5 zeolite is strongly governed by the variety of the templates used in the synthesis, and the zeolites templated by TEABr and HDA present the orthorhombic symmetry, while those prepared using TPABr and TPAOH as templates exhibit only monoclinic symmetry . Furthermore, the distribution of the structural defects in the obtained zeolites was found to be also dependent on the templates used. These T-atom defect sites in the framework, defined as Si(OSi)3O-,are available for the insertion of Ti atoms in the subsequent reaction with titaniuintetrachloride vapor at elevated temperatures and the concentration of defects was proved to be correlative to the amounts of Ti atoms being derived into the framework of zeolite.

Key words: MAS NMR, IR, ZSM-5 zeolites, Ti-ZSM-5 zeolites, Indirect synthesis