Q. Li et al. / Journal of Molecular Catalysis A: Chemical 270 (2007) 44–49
49
oxygen in carbonyl of 2-hydroxypropyl carbamate interacted
References
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The synthesis of propylene carbonate from urea and 1,2-
propanediol was stepwise reaction, and the second step was
rate-determined. The acid–base properties of metal oxides had a
great influence on the catalytic performance for the reaction. The
amphoteric ZnO had the best catalytic activity, while the activ-
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oxides showed no activity. Urea was catalyzed decomposition to
form the isocyanate species in the process of alcoholysis at first.
The metal cations of amphoteric and basic oxides with strong
electrophilicity were favorable to the formation of isocyanate
species. The acidic oxides hardly had any catalytic activity
toward urea decomposition. There were consistency between
the catalytic performance for synthesis of propylene carbonate
and the catalytic activity of urea decomposition. The formation
of isocyanate species played an important role in the reaction.
The catalysis in the conversion of 2-hydroxypropyl carbamate
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