Chinese Journal of Chemical Engineering ›› 2019, Vol. 27 ›› Issue (10): 2447-2454.doi: 10.1016/j.cjche.2019.03.005

• Catalysis, kinetics and reaction engineering • Previous Articles     Next Articles

Chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism and kinetics

Xiaoxu Han, Ying Li, Hualiang An, Xinqiang Zhao, Yanji Wang   

  1. Hebei Provincial Key Lab of Green Chemical Technology and Efficient Energy Saving, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China
  • Received:2018-06-13 Revised:2019-03-11 Online:2019-10-28 Published:2020-01-17
  • Contact: Xinqiang Zhao
  • Supported by:
    Supported by National Natural Science Foundation of China (21476058, 21506046) and Natural Science Foundation of Tianjin City (16JCQNJC06100).

Abstract: The chitosan was found to possess an excellent catalytic performance in n-butyraldehyde selfcondensation to 2E2H. Under suitable conditions, the conversion of n-butyraldehyde, the yield and selectivity of 2E2H separately attained 96.0%, 86.0% and 89.6%. The chitosan catalyst could be recovered and used for 5 times without a significant deactivation after being treated with ammonium hydroxide. In order to elucidate the reaction mechanism, the adsorption and desorption of n-butyraldehyde on the surface of chitosan were studied using in situ FT-IR spectroscopy analysis. The result showed that n-butyraldehyde interacts with-NH2 group of chitosan to form an intermediate species with an enamine structure. Then the reaction process of n-butyraldehyde self-condensation was monitored by React-IR technique and it was found that n-butyraldehyde self-condensation to 2-ethyl-3-hydroxyhexanal followed by a dehydration reaction to 2-ethyl-2-hexenal. On this basis, chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism was speculated and its reaction kinetics was investigated. The self-condensation reaction follows auto-catalytic reaction characteristics and then the corresponding kinetic model was established.

Key words: n-Butyraldehyde, Chitosan, Reaction, Mechanism, Kinetics, Autocatalysis