Organic compound modification of CeO2 and 2-cyanopyridine hybrid catalyst in carbonate synthesis from CO2 and alcohols

Masazumi Tamura, Daiki Hiwatashi, Yu Gu, Akira Nakayama, Yoshinao Nakagawa, Keiichi Tomishige

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of surface modification of CeO2 and 2-cyanopyridine hybrid catalyst with organic compounds was investigated by using dialkyl carbonate synthesis from CO2 and alcohols. Phenol is the useful modifier for CeO2 and 2-cyanopyridine hybrid catalyst without drastic decrease of the activity. Based on the characterizations of phenol-modified CeO2 and 2-cyanopyridine hybrid catalyst such as TG-DTA, GC, FTIR and UV–vis, phenol and 2-cyanopyridine were adsorbed on CeO2 at the same time and the adsorption ratio to the surface Ce on CeO2 is estimated to be 0.11 and 0.12, respectively (2-cyanopyridine/Ce on CeO2 surface = 0.12, phenol/Ce on CeO2 surface = 0.11). The reactivity of alcohols was changed by the addition of phenol due to the steric hindrance of phenol adsorbed on CeO2. The effect of the steric hindrance was large at the C2 and C3 positions of alcohols, which corresponds to the C2 and C3 positions of phenol. The reactivity was drastically decreased in the cases of C2 position-branched alcohols compared with the case without phenol addition, and the yield ratio (The yield without phenol/the yield with phenol) increased: 61 in the case of 2-ethyl-1-butanol, 9.9 in the case of 2-methyl-1-butanol, and 3.7 in the case of 1-butanol. From the DFT calculations, phenol is adsorbed nearby 2-cyanopyridine adspecies by the π-π interaction between the aromatic rings of these chemicals to decrease the reaction space over CeO2, resulting in the reactivity decrease of the steric alcohols, particularly the alcohols with substituents at the C2 position. Therefore, phenol can restrict the reaction field of CeO2 and 2-cyanopyridine hybrid catalyst by the steric hindrance, enabling the control of the reactivity of alcohols in the synthesis of dialkyl carbonates from CO2 and alcohols.

Original languageEnglish
Article number101744
JournalJournal of CO2 Utilization
Volume54
DOIs
Publication statusPublished - 2021 Dec

Keywords

  • Carbon dioxide
  • Cerium oxide
  • Dialkyl carbonate
  • Reactivity control
  • Surface modification

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Waste Management and Disposal
  • Process Chemistry and Technology

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