CeO2-catalyzed direct synthesis of dialkylureas from CO2 and amines

Masazumi Tamura, Kazuki Ito, Yoshinao Nakagawa, Keiichi Tomishige

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

CeO2 showed higher activity for the direct synthesis of 1,3-dibutylurea (DBU) from CO2 and n-butylamine than the metal oxides tested. The solvent largely influenced the reaction over CeO2, and N-methylpyrrolidone (NMP) was preferable among various solvents tested from the viewpoints of activity and selectivity. The catalyst system composed of CeO2 catalyst and NMP solvent (CeO2 in NMP) was applicable to the reactions of various amines such as linear primary alkylamines or branched primary alkylamines, although tert-butylamine afforded low conversion. In contrast, secondary amines and aniline provided no yield of the ureas. The combination of 2-cyanopyridine with CeO2 in NMP (CeO2 in NMP with 2-cyanopyridine) promoted the transformation of the unreactive amines, showing that tert-butylamine and aniline were converted to the corresponding ureas in 82% and 80% yields, respectively. These yields are much higher than those reported in the previous literatures, indicating that CeO2 in NMP with 2-cyanopyridine drastically promoted transformation of amines with low reactivity.

Original languageEnglish
Pages (from-to)75-85
Number of pages11
JournalJournal of Catalysis
Volume343
DOIs
Publication statusPublished - 2016 Nov 1

Keywords

  • Carbon dioxide
  • Cerium oxide
  • Heterogeneous catalyst
  • N-Methylpyrrolidone
  • Urea

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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