Metalloporphyrin-catalyzed homogeneous oxidation in supercritical carbon dioxide

✍ Scribed by Eva R. Birnbaum; Richard M. Le Lacheur; April C. Horton; William Tumas

• Book ID: 104424064
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 535 KB
• Volume: 139
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(98)00172-1

✦ Synopsis

We report results from a study of the reactivity of the halogenated porphyrins tetrakis pentafluorophenyl porphyrinato Ž .

w Ž . x Ž . Ž . w Ž . x iron III chloride Fe TFPP Cl and b-octabromo-tetrakis pentafluorophenyl porphyrinato iron III chloride Fe TFPPBr Cl 8 with dioxygen and cyclohexene in supercritical carbon dioxide. A lower limit for the solubility of the iron porphyrins in sc CO was determined. Both halogenated metalloporphyrins were active catalysts for oxidation of cyclohexene to epoxide and 2

Ž

. allylic oxidation products in sc CO . In 12 h at 808C, up to 350 and 580 turnovers were observed for Fe TFPP Cl and 2 Ž . Fe TFPPBr Cl, respectively. We have also explored several organic solvent reactions at high temperature and pressure to 8 benchmark relative activity and selectivity. Activity is higher in organic solvent, but accompanied by substantial oxidation Ž . of, or reaction with the solvent. Selectivity for epoxidation with Fe TFPPBr Cl is higher in sc CO than in organic solvents, 8 2

with up to 34% cyclohexene oxide produced.