Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (4): 477-485.DOI: 10.1016/S1872-2067(19)63281-X

• Article • Previous Articles     Next Articles

Tuning the product selectivity of SAPO-18 catalysts in MTO reaction via cavity modification

Jiawei Zhonga,b,d, Jingfeng Hana, Yingxu Weia, Shutao Xua, Tantan Suna, Shu Zenga, Xinwen Guob, Chunshan Songb,c, Zhongmin Liua   

  1. a National Engineering Laboratory for Methanol to Olefins, State Energy Low Carbon Catalysis and Engineering R & D Center, Dalian National Laboratory for Clean Energy, iChEM(Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    b State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China;
    c EMS Energy Institute, Departments of Energy and Mineral Engineering, and of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA;
    d University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-11-13 Revised:2018-12-19 Online:2019-04-18 Published:2019-03-14
  • Supported by:

    This work was supported by the Key Research Program of Frontier Sciences, CAS (QYZDY-SSW-JSC024), the National Natural Science Foundation of China (21603223, 21473182, 91334205, 91545104), and the Youth Innovation Promotion Association of the CAS (2014165).

Abstract:

The AEI cavity of SAPO-18 catalyst was modified with zinc cations with the conventional ion exchange procedure. The cavity modification effectively tunes the product selectivity, and shifts the products from mainly propylene to comparable production of ethylene and propylene in methanol to olefin (MTO) reaction. The incorporation of zinc ions and the generation of bicyclic aromatic species in the AEI cavity of SAPO-18 catalysts introduce additional diffusion hindrance that exert greater influence on the relatively bulky products (e.g. propylene and higher olefins), which increase the selectivity to small-sized products (e.g. ethylene). It appears that the incorporated zinc cations facilitate the generation of lower methylbenzenes which promote the generation of ethylene. The cavity modification via incorporating zinc ions effectively tunes the product selectivity over SAPO molecular sieves with relatively larger cavity, which provides a novel strategy to develop the potential alternative to SAPO-34 catalysts for industrial MTO reaction.

Key words: SAPO-18, Methanol to olefin, Cavity modification, Product selectivity