Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (1): 34-42.doi: 10.3866/PKU.WHXB201311121

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Proton Transfer in Reaction between 2,4-Diisocyanatotoluene and Amine Compounds

WANG Xiao-Xuan1, HU Wei2, GUI Da-Yong1, CHI Xu-Hui2, WANG Ming-Liang1, TIAN De-Yu1, LIU Jian-Hong1, MA Xin-Gang2, PANG Ai-Min2   

  1. 1 College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P. R. China;
    2 Hubei Institute of Aerospace Chemotechnology, Xiangfan 441003, Hubei Province, P. R. China
  • Received:2013-07-15 Revised:2013-11-12 Published:2014-01-01
  • Contact: WANG Ming-Liang E-mail:wangml@szu.edu.cn
  • Supported by:

    The project was supported by the National Defense Foundation of China (973) (613142), National Natural Science Foundation of China (20673073), and Foundation of Shenzhen Key Laboratory of Functional Polymer, China (FP20130007).

Abstract:

The effects of proton transfer on the reaction between 2,4-diisocyanatotoluene (2,4-TDI) and active-hydrogen-containing amine compounds were calculated using density functional theory (DFT) at the B3LYP/6-31+G(d, p) level. The energy barriers are significantly reduced when a methanol molecule serves as a proton transporter or a reactive catalyst, indicating that the labile hydrogen-containing compound plays a key role in accelerating the reaction rate and proton transfer. The catalytic addition of 2,4-TDI and methyl N-methylcarbamate follows a one-step mechanism, with a transition state characterized by a sixmembered ring. However, the catalytic additions of 2,4-TDI and aromatic amines such as N-methyl-p-nitroaniline, diphenylamine, and 1,2-dihydro-2,2,4-trimethylquinoline involve two steps, with the first step as the rate-limiting step. The reactions between 2,4-TDI and aromatic amines have lower energy barriers than that between 2,4-TDI and methyl N-methylcarbamate. The aromatic amines are more active than methyl N-methylcarbamate in the reaction with 2,4-TDI, which is in a good agreement with experimental results.

Key words: Density functional theory, Proton transfer, 2,4-Diisocyanatotoluene, Urethane formation

MSC2000: 

  • O643.12