Promotional effect of CH3I on hydroxycarbonylation of cycloalkene using homogeneous rhodium catalysts with PPh3 ligand

Tomoharu Oku, Masaki Okada, Maneeporn Puripat, Miho Hatanaka, Keiji Morokuma, Jun Chul Choi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The reaction mechanism of the hydroxycarbonylation of cyclohexene with formic acid to form cyclohexanecarboxylic acid using organorhodium complexes was investigated both experimentally and computationally. It was found that excess CH3I and PPh3 promote this reaction. The active catalyst species was determined to be a five-coordinated rhodium hydride 16-electron complex derived from a mononuclear rhodium 16-electron complex (Vaska-type complex). PPh3 and CH3I played the following roles: i) to promote the formation of the Vaska-type Rh complex from Rh2Cl2(CO)4 (1), ii) to aid the elimination of the PPh3 ligand from the Vaska-type complex by stabilizing the free energy of formation of a mononuclear three-coordinated rhodium 14-electron complex through the formation of phosphonium iodide ([Ph3P(CH3)]I), and iii) to generate the active rhodium hydride species.

Original languageEnglish
Pages (from-to)1-5
Number of pages5
JournalJournal of CO2 Utilization
Publication statusPublished - 2018 May
Externally publishedYes


  • CO
  • Formic acid
  • Hydroxycarbonylation
  • Organorhodium complex
  • Reaction mechanism

ASJC Scopus subject areas

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


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