GB642459A - Improvements in or relating to organic oxidation reactions - Google Patents

Abstract

Organic compounds are oxidized by reacting with an alkali metal hypochlorite and a minor proportion, e.g. up to 7 per cent, of an alkali metal permanganate or manganese dioxide in the presence of an alkaline medium such as caustic soda or caustic potash solution or lime. Sodium hypochlorite is the preferred hypochlorite, particularly when used with potassium permanganate, the preferred permanganate. When manganese dioxide is used it should preferably be freshly precipitated. The oxidation effected may result in ring rupture, e.g. naphthalene to phthalic acid, oxidation of side chains, e.g. toluene to benzoic acid and p-toluic acid to terephthalic acid or non-cyclic compounds may be oxidized, e.g. 1,1,2-trichloro3,3,3-trifluoropropene-1 to trifluoroacetic acid. In examples: (1) 1,1,2-trichloro-3,3,3-trifluoropropene is slowly added to an aqueous solution of sodium hydroxide, sodium hypochlorite and potassium permanganate at 80 DEG C. over 2 1/2 hours maintaining a reflux and then for 11 1/2 hours at 89 DEG C., when unchanged trichloro-trifluoropropene is removed and the remainder made slightly acid with sulphuric acid, sulphur dioxide then being passed in until no colour is obtained with starch-iodide when the solution is neutralized with soda ash after filtration, evaporated to dryness and dried, the powdered residue being extracted with absolute alcohol and sodium trifluoroacetate obtained on removal of the alcohol; (2) toluene is added to a solution composed of the above oxidants maintained at 95 DEG C. for 13 1/2 hours when benzoic acid is recovered in a conventional manner; and (3) naphthalene is added to an aqueous solution of caustic potash, sodium hypochlorite and potassium permanganate and refluxed for 29 hours when phthalic acid is isolated in a known manner. Specification 577,481 is referred to.