Aminolysis of O-methyl-N-methylcarbamate as a model for the production of polyureas. a DFT study

Model reaction of the formation of aliphatic polyureas—the reaction of O-methyl-N-methylcarbamate with methylamine was studied at the M06 and B3LYP levels. Concerteted non-catalytic nucleophilic substitution reactions involving a monomer and dimer of methylamine proceed through large free energy barriers. Non-catalytic reactions with a monomer or dimer of methylamine proceed according to the “addition–elimination” pathway, the stages that determine the reaction rate are the formation of a tetrahedral intermediate. They also have large free energy barriers. Catalysis with zinc acetate, phenol, and 1,4-diazabicyclo[2.2.2]octane does not significantly change the energy barrier. A sharp decrease in activation barriers to the reaction occurs during catalysis with sodium hydroxide and sodium methoxide.