SCI和EI收录∣中国化工学会会刊

›› 2017, Vol. 25 ›› Issue (10): 1435-1441.DOI: 10.1016/j.cjche.2017.03.012

• Catalysis, Kinetics and Reaction Engineering • Previous Articles     Next Articles

Kinetics of water-isocyanate reaction in N,N-dimethylformamide

Zhirong Chen, Weitao Yang, Hong Yin, Shenfeng Yuan   

  1. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
  • Received:2016-12-01 Revised:2017-03-08 Online:2017-03-22 Published:2017-10-28
  • Supported by:
    Supported by the Key Science and Technology Innovation Team of Zhejiang Province(2011R50007).

Kinetics of water-isocyanate reaction in N,N-dimethylformamide

Zhirong Chen, Weitao Yang, Hong Yin, Shenfeng Yuan   

  1. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
  • 通讯作者: Hong Yin,E-mail address:yinh@zju.edu.cn
  • 基金资助:
    Supported by the Key Science and Technology Innovation Team of Zhejiang Province(2011R50007).

Abstract: The uncatalyzed reaction of p-tolyl isocyanate (p-TI) with water in N,N-dimethylformamide (DMF) was investigated by high performance liquid chromatography (HPLC). The reactions were carried out at different temperatures from 293 K to 323 K, using various molar ratios of water to p-TI. DMF, as a special amide, was proved to be an efficient catalyst for water-isocyanate reaction. Under the reaction conditions in this study, substituted urea was the only final product observed. An appreciable amount of intermediate p-toluidine was detected. Concentrations of the isocyanate group as well as the amine and urea were determined as a function of time. New kinetic equations were deduced for each of the substance on the basis of a multistep mechanism, instead of a simple second order reaction as usual. Kinetic constants were calculated using the software MATLAB. Furthermore, the effects of temperature and concentrations of reactants on the reaction rate and amine content were discussed. The activation energy of each step was also determined.

Key words: Kinetics, Isocyanate, Polyurethane, Catalysis, HPLC, Kinetic modeling

摘要: The uncatalyzed reaction of p-tolyl isocyanate (p-TI) with water in N,N-dimethylformamide (DMF) was investigated by high performance liquid chromatography (HPLC). The reactions were carried out at different temperatures from 293 K to 323 K, using various molar ratios of water to p-TI. DMF, as a special amide, was proved to be an efficient catalyst for water-isocyanate reaction. Under the reaction conditions in this study, substituted urea was the only final product observed. An appreciable amount of intermediate p-toluidine was detected. Concentrations of the isocyanate group as well as the amine and urea were determined as a function of time. New kinetic equations were deduced for each of the substance on the basis of a multistep mechanism, instead of a simple second order reaction as usual. Kinetic constants were calculated using the software MATLAB. Furthermore, the effects of temperature and concentrations of reactants on the reaction rate and amine content were discussed. The activation energy of each step was also determined.

关键词: Kinetics, Isocyanate, Polyurethane, Catalysis, HPLC, Kinetic modeling