Aldehydes manganese acetate

In a batch operation process, aldehyde having 0.5 per cent of manganese acetate dissolved in it is warmed to 20° to 25° C. in an autoclave. Air is then introduced until the total pressure rises to from 75 to 120 pounds per square inch. The temperature rises to about 65° C. during... 

The toluic aldehyde/HBF complex is then decomposed by heating between 130 and 180 C in the presence of a solvent (benzene). The BF3. HF and unconverted toluene are recovered and recycled. The o- and p-tohiic aldehydes are separated by crystallization. Purified p-toluic aldehyde is air-oxidized (in solution m acetic add) in the presence of manganese acetate, cobalt acetate and sodium bromide, by the technique employed for p-xylene. This takes place around 200°C, at 2.10 Pa absolute ... 

The ring synthesis of the tetrahydro-1,3-azoles is simply the formation of N,N-, N,0-or A, S-analogues of aldehyde cyclic acetals the ring synthesis of the 4,5-dihydro-heterocycles requires an acid oxidation level in place of aldehyde. A good route to the aromatic systems is therefore the dehydrogenation of these reduced and partially reduced systems. Nickel peroxide, " manganese(IV) oxide, copper(II) bromide/ base, and bromotrichloromethane/diazabicycloundecane have been used. The example shown uses cysteine methyl ester with a chiral aldehyde to form the tetrahydrothiazole. 

It is proposed to oxidize a batch of 1000 liters of -butyraldehyde dissolved in n-bulyric acid in the presence of 0.1 % manganese acetate as a catalyst at essentially atmospheric pressure in a mechanically agitated contactor by passing air continuously through it. Given the following data, calculate the time required to obtain a conversion corresponding to a drop in the aldehyde concentration [.B]j from 6.0 to 0.85 x 10 niol/cm ... 

Manganese dioxide at 200° oxidises alcohol to aldehyde and is itself reduced to Mn203 at 250° the Mn303 brings about further oxidation and tho products are acetaldehyde, carbon dioxide, and acetic acid. 

The most important applications of peroxyacetic acid are the epoxi-dation [250, 251, 252, 254, 257, 258] and anti hydroxylation of double bonds [241, 252, the Dakin reaction of aldehydes [259, the Baeyer-Villiger reaction of ketones [148, 254, 258, 260, 261, 262] the oxidation of primary amines to nitroso [iJi] or nitrocompounds [253], of tertiary amines to amine oxides [i58, 263], of sulfides to sulfoxides and sulfones [264, 265], and of iodo compounds to iodoso or iodoxy compounds [266, 267] the degradation of alkynes [268] and diketones [269, 270, 271] to carboxylic acids and the oxidative opening of aromatic rings to aromatic dicarboxylic acids [256, 272, 271, 272,273, 274]. Occasionally, peroxyacetic acid is used for the dehydrogenation [275] and oxidation of aromatic compounds to quinones [249], of alcohols to ketones [276], of aldehyde acetals to carboxylic acids [277], and of lactams to imides [225,255]. The last two reactions are carried out in the presence of manganese salts. The oxidation of alcohols to ketones is catalyzed by chromium trioxide, and the role of peroxyacetic acid is to reoxidize the trivalent chromium [276]. 

Many other metal ions have been reported as catalysts for oxidations of paraffins or intermediates. Some of the more frequently mentioned ones include cerium, vanadium, molybdenum, nickel, titanium, and ruthenium [21, 77, 105, 106]. These are employed singly or in various combinations, including combinations with cobalt and/or manganese. Activators such as aldehydes or ketones are frequently used. The oxo forms of vanadium and molybdenum may very well have the heterolytic oxidation capability to catalyze the conversion of alcohols or hydroperoxides to carbonyl compounds (see the discussion of chromium, above). There is reported evidence that Ce can oxidize carbonyl compounds via an enol mechanism [107] (see discussion of manganese, above). Although little is reported about the effectiveness of these other catalysts for oxidation of paraffins to acetic acid, tests conducted by Hoechst Celanese have indicated that cerium salts are usable catalysts in liquid-phase oxidation of butane [108]. 

The roles of manganese in TPA manufacture are better understood than in the Witten process, and include decomposition of the CH2COOH radical (derived from the acetic acid solvent) and regeneration of the bromine atom promoter [13], In an effort to eliminate halogen compounds which are highly corrosive to oxidation equipment, use of acetaldehyde [14] and paraldehyde [15] has been developed. These aldehyde promoters are ultimately converted to acetic acid in high yield. For economic reasons, these aldehyde processes have been abandoned in favor of the bromine-promoted Amoco process. 

Pinacol coupling and attylation. Either activated manganese alone" or Mn-CrClj-MejSiCl effects pinacol coupling of aromatic aldehydes. The reaction can also be mediated by Mn in aqueous acetic acid, but with Mn-Cu and in the presence of allyl halides allylation becomes the major reaction course. ... 

When single metallic oxide catalysts such as magnesium oxide supported on wood charcoal are used at a temperature of 420° to 430° C., a mixture of butanol, ethyl acetate, and aldehyde is obtained from ethanol. When manganese carbonate or zinc oxide supported on wood charcoal is used at 450°, ethanol decomposes into only butanol and aldehyde.65... 

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