Alcohol oxidation, molybdenum chloride

Molybdenum- and tungsten-containing heteropolyanions are also effective catalysts for alcohol oxidations with H2O2 (134-136]. For example, H3PM012O40 or H3 PW12O40, in combination with cetylpyridinium chloride as a phase transfer agent, were shown by Ishii and coworkers [137] to be effective catalysts for alcohol oxidations with H2O2 in a biphasic, chloroform/water system. 

Other molybdenum complexes able to catalyze the selective oxidation of secondary alcohols are ammonium molybdate in the presence of H202,30 benzyltrimethylammonium tetrabromooxomolybdate in the presence of r-BuOOH31 and molybdenum hexacarbonyl in the presence of catalytic cetylpyridinium chloride and stoichiometric t-BuOOH.32... 

The pentachloride is a little unstable in air when heated to about 1380° C. or less it leaves a residue of molybdenum when heated in hydrogen at 250° C. it is reduced to amorphous molybdenum trichloride. Its aqueous solution is unstable in air, especially on warming, when hydrogen chloride is more rapidly evolved and the blue oxide (p. 131) remains. Decomposition of its solution in hydrochloric acid also readily takes place. In alcohol and ether it dissolves to a green solution in sulphuric acid its solution is bluish green and in nitric acid colourless alkalies dissolve it with production of the hydrated dioxide and a molybdate. ... 

Electrolytes used are sulfuric acid, hydrochloric acid, sodium hydroxide, inorganic salts, and organic salts. Glacial acetic acid, methyl alcohol, and ethyl alcohol have also been found useful. Promoters are stannous chloride, copper sulfate, mercurous sulfate, antimony oxides, ketones, and salts of lead, titanium, molybdenum, and vanadium. 

Oxidative Methods.— The oxidation of alcohols to carbonyl compounds using DMSO activated by electrophiles, e.g. oxalyl chloride or trifluoroacetic anhydride, has been reviewed/ DMSO-Metal oxide oxidations of alcohols have been described using molar, or catalytic, amounts of a new oxide of molybdenum/ This yellow oxide, Mo-y , is prepared by hydrogen peroxide oxidation of molybdenum or its trioxide/ N Iodosuccinimide in combination with tetra-butylammonium iodide oxidizes primary and secondary alcohols to aldehydes and ketones in dichloromethane solution/ The corresponding bromo-combina-tion gave inferior yields, and the chloro-combination resulted in polychlorination of the carbonyl product. 

Manning, Ball, and Menis (162) have carried out polarographic and coulometric reductions of molybdenum (VI) in a nitrilotriacetic acid medium and have applied their findings to the analysis of thorium-uranium oxide mixtures. The determination of molybdenum in steel using coulometric techniques has been reported by Ibrahim and Nair (163) who reduced molybdenum at —0.40 V vs. SCE in a sodium acetate buffered chloride medium. Chromium interference can be removed by pre-reduction with alcohol. The catalytic effect of lower oxidation states of molybdenum in the reduction of perchlorate has been used as an indirect electro-analytical method for the determination of perchlorate (159, 164). 

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