Alcohols, benzylic with permanganates

The final residue from the mother liquor is an oil which does not solidify in a freezing mixture, and appears to be a mixture of p- and w-tolylcarbinols. Only a trace of phthalic acid (phenolphthalein test) was obtained by oxidizing this oil with permanganate the portion of it which was more readily soluble in water yielded a phenylurethan which depressed the melting point of the phenylurethan of either />-tolylcarbinol or benzyl alcohol. 

Alkyl groups can be oxidized, as for example the benzyl group in compound (148), to a benzoyl group by permanganate or (better) by selenium dioxide.42 Similarly, the benzyl alcohol in compound 149 is oxidized by manganese dioxide.87 The thiol 150, treated with ferricyanide, gives the disulfide 151.65 Oxidation of thiol 150 with nitric acid is thought to... 

Benzyl alcohol readily undergoes the reactions characteristic of a primary alcohol, such as esterification and etherification, as well as halide formation. In addition, it undergoes ring substitution. In the presence of acid, polymerization is observed, and the alcohol can be thermally dehydrated to toluene [108-88-3], Catalytic oxidation over copper oxide yields benzaldehyde benzoic acid is obtained by oxidation with chromic acid or potassium permanganate. Catalytic hydrogenation of the ring gives cyclohexylmethanol [100-49-2]. 

Solid-phase extraction is routinely used to clean up extracts prior to quantitation (19,42,70, 80-82). Alternatively, endogenous fluorescent artifacts in food samples can be eliminated by oxidation with potassium permanganate/hydrogen peroxide/sodium metabisulphite. Benzyl alcohol has been used to extract riboflavin selectively without the coenzymes, permitting the determination of free riboflavin. 

Similar results are obtained when saturated and benzylic alcohols are stirred at room temperature or refluxed in dichloromethane with cupric permanganate octahydrate, Cu(Mn04)2 8H20. The octahydrate reacts faster than the anhydrous salt. Decanol and benzyl alcohol give 91 and 84% yields of decanoic acid and benzoic acid, respectively, at room temperature after 24 h [894. ... 

D) Action of Alcoholic Alkali. Use alcoholic potassium hydroxide solution containing 30 g of the solid dissolved in 90 ml of 90 per cent methyl or ethyl alcohol. Place 3 ml of the alkali solution in each of three tubes. Add to seperate respective tubes 1 ml of n-amyl bromide, amyl bromide, and benzyl chloride. Shake gently for a minute, cork, label each tube, and set aside for the next laboratory period. If it is desired to observe the rate at which the halides react, examine after 30 minutes the extent of the reaction as judged by the amount of potassium halide formed. After 24 hours add 3 ml of water, shake, and allow to separate. Note the odor. With a clean dropper or pipette withdraw two drops from each and test with bromine water and dilute permanganate. n -Amyl bromide yields a considerable amoimt of ether, but little olefin. Benzyl chloride yields entirely carbinol. Put the contents of the three tubes into bottles provided by the instructor. 

Kumar A, Jain N, Chauhan SMS (2004) Oxidation of benzylic alcohols to carbonyl compounds with potassium permanganate in ionic liquids. Synth Commun 34 2835-2842... 

Kinetic studies of the oxidation of aromatic hydrocarbtSns with potassium permanganate show that reaction is first order with respect to each reactant. With toluene, oxidation takes place almost exclusively at the methyl group to give successively benzyl alcohol, benzaldehyde, and benzoic acid with ethyl benzene, attack is predominantly at the alpha carbon atom to yield acetophenone and with n- and isopropylbenzene, the products are propiophenone and acetophenone, respectively, plus benzoic acid. These results are of interest primarily for mechanism studies. 

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