Synergetic combination of catalysis of the phase transfer-electron transfer type for the oxidation of alcohols or hydrocarbons

✍ Scribed by Iwao Tabushi; Noboru Koga

• Publisher: Elsevier Science
• Year: 1979
• Tongue: French
• Weight: 212 KB
• Volume: 20
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)95496-6

✦ Synopsis

Successful synergetic combination of the electron-transfer catalyst, TPPMn, and the phase-transfer catalyst, TOMA, in the oxidation of alcohols or hydrocarbons were reported.

We have already reported that ethers or alcohols were very readily (within a few minutes at room temperature) oxidized by a pontential oxidizing reagent, hematoporphyrin-Mn(IV) complex "* (abbreviated as Hm.Mn(IV)), which also decomposed water in the neutral condition as a possible model of the plant photosystem II.3r4 Since many oxidation reactions of organic compounds with inorganic oxidants, just like many other substitution reactions with inorganic reagents, were effectively catalyzed by a phase transfer reagent, 5 it is quite reasonable to assume that the Mn-porphyrin catalyzed oxidations mentioned above may be further catalyzed by an appropriate phase transfer reagent. In this article, the authors wish to report that the electron transfer type catalyst, TPP.Mn(lIt) (abbreviation of meso-tetraphenylporphyrin), acts synergetically with a common phase transfer catalyst, trioctylmethylammonium salt (abbreviated as TOMA) to promote the oxidation of benzyl alcohol or many other organic substrates. Benzyl alcohol was stoichiometrically and instantaneously oxidized with TPP.Mn(IV) at room temperature in common organic solvents (equation 1) 1 and the resultant TPP*Mn(IU) was readily re-oxidized with NaOCl at room temperature in aqueous alkaline solution above pH 12 (equation 2).1 The direct oxidation of benzyl alcohol with NaOCl (equation 3) was very slow. The direct oxidation was considerably accelerated by a phase transfer catalyst, TOMA, (equation 4) or by