The role of local structure on formic acid decomposition in supercritical water: A hybrid quantum mechanics/Monte Carlo study

Tetsuo Honma, Hiroshi Inomata

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

We explored water-assisted decompositions of formic acid in supercritical water in terms of local structure near reactant. A hybrid quantum mechanics/molecular mechanics (QM/MM) simulation used in this paper includes QM part as first solvation shell members around the reactant. A present QM/MM approach can simulate supercritical water solution with a reasonable computational load while keeping the simulation preciseness because a density functional theory of B3LYP/6-31+G(d) level was iterated at every 1000 Monte Carlo solute moves. The formic acid converts mainly decarboxylation by water-assisted mechanism, and the coordinated water molecules play an important role for understanding supercritical water density dependence of the reaction. We analyzed a contour map based on the solute-solvent interaction energy along with the reaction pathway. Coordinated water molecule restricted the dehydration pathway by means of hydrogen bond with formic acid, however, the coordinated water promotes the decarboxylation pathway by means of stabilization of the transition state structure with one catalytic water molecule. The contour map of the pair interaction energy along the reaction path elucidates the role of local structure on reactions in supercritical water.

Original languageEnglish
Pages (from-to)238-243
Number of pages6
JournalFluid Phase Equilibria
Volume257
Issue number2
DOIs
Publication statusPublished - 2007 Aug 25

Keywords

  • Hybrid QM/MM simulation
  • Solvation structure
  • Supercritical water

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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