Barium manganate oxidant

A somewhat similar process to the Lahousse has been protected by French patent 447688, 1912, in the names of T eissier and Chaillaux. In this process barium sulphate is heated with manganous oxide, when the following reaction takes place.—... 

When the reaction is complete, steam under pressure is passed over the mixture of barium sulphide and manganous oxide, with the production of hydrogen, in accordance with the following equation —... 

Barium manganate [7787-35-] J M 256.3. Wash with conductivity H2O by decantation until the supernatant gives a faint test for Ba . Remove excess H2O in vac (IMPORTANT), then heat at 100° and the last traces of H2O are removed in a vac desiccator over P2O5. Store over KOH. It disproportionates in hot H2O or dil acid to Ba(MnO2)2 and Mn02, and is a mild oxidant. [7ACS 44 1965 1924-, Inorg Synth 11 56 I 960]. 

Barium manganate (BaMn04) was a little known oxidant in organic synthesis till Firouzabadi et al. published in 1978 83 two foundational papers76 showing that it behaves against alcohols in a similar way as active MnC>2. 

Cyclopentanone has been prepared from adipic acid by distilling the calcium salt,1 heating alone 2 or with acetic anhydride,3 or in the presence of various catalysts such as barium hydroxide,4 thorium oxide,5 manganous oxide,5 uranium nitrate,6 ferrous sulfate 6 and others.7... 

Teissier and Chaillaux8 suggest the employment of barytes and manganous oxide which are heated together to redness with the production of manganese dioxide and barium sulphide ... 

Selective oxidation. The diol 1 is oxidized to the lactone 3 (cinnamolide) in 55% yield by Collins reagent. The same oxidation with AgiCOi/Celite (Fetizon reagent) is essentially quantitative. The cheaper barium manganate is equally effective, and has the advantage that the intermediate lactol 2 can also be obtained if desired. 

OXIDATION, REAGENTS Barium mangan-ate. Benzyl(triethyl)ammonium permanganate. Bispyridinesilver permanganate. Bis(trimethylsilyl)peroxide. t-Butyl hydroperoxide. t-Butyl hydroperoxide-Benzyltri-methylammonium tetrabromooxomolyb-dale. t-Butyl hydroperoxide-Bisoxobis-(2,4-pentadionato)molybdenum. t-Butyl hydroperoxide-Chromium carbonyl. t-Bu-tyl hydroperoxide-Dialkyl tartrate-Titan-ium(IV) isopropoxide. t-Butyl hydroper-... 

The selective oxidation of diols in which one or both hydroxy groups are allylic has been reported on a number of occasions. Reagents which have proved use for this include silver carbonate on Celite, barium manganate/ and manganese dioxide, as illustrated in equations (29)-(31). 

Baeyer-Villiger oxidation, 56, 196, 324, 509 Barium manganate, 23 Barium oxide, 23 Beckmann rearrangement, 472 Benzal chlorides, 465 Benzeneboionic acid, 23-24 7) -Benzenechiomium tricarbonyl, 117 Benzeneselenenic acid, 24 Benzeneselenenic anhydride, 2S Benzeneselenenyl bromide, 25-32 Benzeneselenenyl chloride, 25-32 Benzeneseleninic acid, 32 Benzeneseleninic anhydride, 32-34 Benzeneselenocyanate-Copper(II) chloride, 34-35... 

Oxidation of allylic aicohols. Barium manganate is also effective for this oxidation. Thus 1 is oxidized to the ketone 2 in 80-85% yield. The yield with MnOj as oxidant is 38%. Two-phase Jones oxidation gives a complex mixture. 

Barium manganate, BaMn04, is commercially available. The dark-blue crystals are obtained from aqueous solutions of barium chloride and potassium permanganate [552, 555]. It oxidizes alcohols, especially benzylic alcohols, to carbonyl compounds [552, 555] hydroquinone to quinone [555] benzylamines to benzaldehydes [555] aromatic amines to azo compounds [555] and phosphines to phosphine oxides [555],... 

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 oxidation of diols having alcoholic groups of the same nature, for example, both alcoholic groups are primary, secondary, allylic, or benzylic, is usually carried out at both groups to yield dialdehydes [832] or diketones [552], Such reactions are achieved by chromium trioxide [582], barium manganate [832], dimethyl sulfoxide activated with acetic anhydride [1013], and others (equations 284 and 285). 

More common oxidation reagents are oxygen in the presence of cobalt peroxide [1136], manganese dioxide [Si3], barium manganate [S53], silver permanganate [897], and nickel peroxide [936] (equation 495). 

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