Chinese Journal of Catalysis ›› 2024, Vol. 64: 133-142.DOI: 10.1016/S1872-2067(24)60097-5

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Deactivation mechanism of acetone to isobutene conversion over Y/Beta catalyst

Chang Wanga, Tingting Yanb,*(), Weili Daia,*()   

  1. aSchool of Materials Science and Engineering, Nankai University, Tianjin 300350, China
    bCollege of Science, Civil Aviation University of China, Tianjin 300300, China
  • Received:2024-05-30 Accepted:2024-07-09 Online:2024-09-18 Published:2024-09-19
  • Contact: * E-mail: weilidai@nankai.edu.cn (W. Dai),ttyan@cauc.edu.cn (T. Yan).
  • Supported by:
    National Natural Science Foundation of China(22272083);National Natural Science Foundation of China(22302228)

Abstract:

The conversion of acetone derived from biomass to isobutene has attracted extensive attentions. In comparison with Brønsted acidic catalyst, Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity. However, the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now. Herein, the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques, including acetone-temperature-programmed surface reaction, gas chromatography-mass spectrometry, in situ ultraviolet-visible, and 13C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy. A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites. In comparison with the low reaction temperature, a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed, and which could strongly adsorb on the Lewis acidic sites, and thus cause the catalyst deactivation eventually. After a simple calcination, the coke deposits could be easily removed and the catalytic activity could be well restored.

Key words: Deactivation mechanism, Acetone to isobutene, Lewis acid sites, Y/Beta, Spectroscopy