Preparation
Excess ethanolamine and DMDTC were mixed and heated at 60℃ for 15 h. The released malodorous methyl sulfide by-product was absorbed and oxidized by NaOCl solution. When the reaction was complete, the unreacted ethanolamine was removed under reduced pressure by simple distillation, leaving a crude mixture of oxazolidinone and bis(2-hydroxyethyl)urea, which was further purified by recrystallization from methanol/ethyl acetate (1:4.5) to give N,N'-bis(2-hydroxyethyl)urea as colorless crystals.
