Benzophenone preparation from benzhydrol

Barium manganate, prepared from potassium manganate and barium chloride [5JJ] or by the reduction of potassium permanganate with potassium iodide in the presence of barium chloride and sodium hydfoxide [5J2], is used for the quantitative oxidation of benzhydrol to benzophenone. The reaction mixture is refluxed in benzene for 0.5-2 h [SJ5]. The result is comparable with and even better than that of oxidation with manganese dioxide [250, 525]. 

The preparation of benzhydrol from benzophenone is described as an example of reduction of an aromatic ketone 325... 

Benzophenone added to N-lithium-N-benzyl-ferf-butylamide prepared from ben-zyl-r rr-butylamine and methyllithium in ether, and the product isolated after 5 min. benzhydrol. Y 90%. F. e. s. G. Wittig, G. Hteler, and A. Hesse, A. 746, 185, 149, 174 (1971). 

Hypochlorites are very good oxidizers of alcohols and are frequently selective enough to oxidize secondary alcohols in preference to primary alcohols see equations 288-291). Solutions of sodium hypochlorite in acetic acid react exothermically with secondary alcohols within minutes [693]. Calcium hypochlorite in the presence of an ion exchanger (IRA 900) oxidizes secondary alcohols at room temperature in yields of 60-98% [76 5]. Tetrabutylammonium hypochlorite, prepared in situ from 10% aqueous sodium hypochlorite and a 5% dichloromethane solution of tetrabutylammonium bisulfate, oxidizes 9-fluorenol to fluorenone in 92% yield and benzhydrol to benzophenone in 82% yield at room temperature in 35 and 150 min, respectively [692]. Cyclohexanol is oxidized to cyclohexanone by teit-butyl hypochlorite in carbon tetrachloride in the presence of pyridine. The exothermic reaction must be carried out with due precautions [709]. 

Oxo compds. from alcohols. Ba(Mn04)2 added to a soln. of benzhydrol in acetonitrile, and the mixture refluxed for 1 h - benzophenone. Y 99%. Ba(Mn04)2 is a mild, stable oxidant, efficiently oxidizing prim, and sec. alcohols in aprotic media, whilst leaving double bonds unaffected sec. benzylic hydroxyl groups are oxidized more rapidly than non-benzylic hydroxy groups. F.e., also oxidation of (3-hydroxyketones, and preparation of disulfides from mercaptans, s. H. Firouzabadi et al.. Synthesis 1989, 378-80. 

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