Synthesis mechanism of dimethylhexane-1,6-dicarbamate from 1,6-hexamethylenediamine, urea and methanol: A molecular scale study based on density functional theory

Tao Yu; Yitao Si; Jiancheng Zhou; Maochang Liu

doi:10.1016/j.jmgm.2022.108349

Synthesis mechanism of dimethylhexane-1,6-dicarbamate from 1,6-hexamethylenediamine, urea and methanol: A molecular scale study based on density functional theory

J Mol Graph Model. 2023 Jan:118:108349. doi: 10.1016/j.jmgm.2022.108349. Epub 2022 Sep 29.

Authors

Tao Yu¹, Yitao Si², Jiancheng Zhou³, Maochang Liu²

Affiliations

¹ School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China; State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi'an Modern Chemistry Research Institute, Xi'an, 710065, China. Electronic address: fischer@wo.cn.
² International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow, Xi'an Jiaotong University, Xi'an, 710049, China.
³ School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.

PMID: 36198249
DOI: 10.1016/j.jmgm.2022.108349

Abstract

This work provides a molecular scale insight into non-phosgene synthesis based on the reaction of dimethylhexane-1,6-dicarbamate from 1,6-hexamethylenediamine, urea and methanol with computational electronic method. By exploring almost all possible reaction modes and comparing the effective barrier of each channel, this work analyzes the optimal reaction mechanism for both non-catalytic and self-catalytic systems. The mechanism without catalysis has a high effective free energy barrier (FEB) of 47.0 kcal mol^-1. As for self-catalytic system, after sorting out the reaction pathway network, an effective FEB of 24.6 kcal mol^-1 is confirmed which corresponds to dissociation of urea.

Keywords: Carbamate; Isocyanate; Non-phosgene; Reaction mechanism; Urea.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Catalysis
Density Functional Theory
Methanol*
Urea*

Substances

Methanol
Urea
1,6-diaminohexane