Process for preparing cyclohexanoneoxime by ammoxidation of cyclohexanone

摘要

Heteropoly acids containing tungsten as the co-ordinating element and phosphorus, silicon, boron, selenium or iodine as the hetero element are made by reacting an aqueous solution of a tungstate with an oxy-acid salt of the hetero element. When the hetero element is phosphorus, a part of the tungsten may be replace by vanadium or molybdenum. Specified acids have the formulae H3[PW12O40].30H2O H4[SiW12O40].7H2O H5[BW12O40].30H2O H3[PW10V2O39].nH2O H4[SeW12O40].nH2O. Example 1 describes the preparation of phosphotungstic acid by heating sodium tungstate with disodium hydrogen phosphate in aqueous hydrochloric acid.ALSO:Cyclohexanone oxime is made by reacting cyclohexanone with ammonia and hydrogen peroxide in the liquid phase in the presence of a catalyst comprising phosphotungstic acid, silicotungstic acid, borotungstic acid, selenotungstic acid, iodotungstic acid, phosphotungstovanadic acid, phosphotungstomolybdic acid or a salt of any of these acids (see Division C1). The reaction may be effected at 5-40 DEG C. in the presence or absence of a solvent, e.g. water or a water-soluble saturated alcohol. The reaction mixture may also include a condensation inhibitor for cyclohexanone, e.g. a phenol derivative, sulphur, a sulphur-containing organic compound, boric acid, phosphoric acid, a borate, a phosphate or a silicate. Examples are given.