Alcohols, primary permanganate

Lead tetraacetate-Manganese(II) acetate, 157 Osmium tetroxide, 222 Potassium ruthenate, 259 Samarium(II) iodide, 270 reagents specific for primary alcohols Osmium tetroxide, 222 reagents specific for benzylic alcohols Cetyltrimethylammonium permanganate, 69... 

Oxidation.1 Hydrated copper permanganate oxidizes alcohols in CH2C12 rapidly and in high yields. Ketones are obtained from secondary alcohols, and carboxylic acids from primary and benzylic alcohols. Primary or secondary allylic alcohols are also oxidized efficiently. Anhydrous reagent is much less active. 

This is not new information. We learned, during our study of the mild oxidation of alcohols (Sec. 13.5.3), that aldehydes undergo mild oxidation to carboxylic acids but ketones are resistant to mild oxidation. Mild oxidation of a primary alcohol with permanganate or dichromate proceeds initially to yield an aldehyde and then the aldehyde is oxidized to a carboxylic acid. Mild oxidation of a secondary alcohol yields a ketone which does not oxidize further. 

By oxidation of primary alcohols with alkaline potassium permanganate solution or with a dichromate and dilute sulphuric add, for example ... 

Oxidation of primary alcohols (Section 15 10) Potassi um permanganate and chromic acid convert primary al cohols to carboxylic acids by way of the corresponding aldehyde... 

Secondary alcohols (C q—for surfactant iatermediates are produced by hydrolysis of secondary alkyl borate or boroxiae esters formed when paraffin hydrocarbons are air-oxidized ia the presence of boric acid [10043-35-3] (19,20). Union Carbide Corporation operated a plant ia the United States from 1964 until 1977. A plant built by Nippon Shokubai (Japan Catalytic Chemical) ia 1972 ia Kawasaki, Japan was expanded to 30,000 t/yr capacity ia 1980 (20). The process has been operated iadustriaHy ia the USSR siace 1959 (21). Also, predominantiy primary alcohols are produced ia large volumes ia the USSR by reduction of fatty acids, or their methyl esters, from permanganate-catalyzed air oxidation of paraffin hydrocarbons (22). The paraffin oxidation is carried out ia the temperature range 150—180°C at a paraffin conversion generally below 20% to a mixture of trialkyl borate, (RO)2B, and trialkyl boroxiae, (ROBO). Unconverted paraffin is separated from the product mixture by flash distillation. After hydrolysis of residual borate esters, the boric acid is recovered for recycle and the alcohols are purified by washing and distillation (19,20). 

Potassium permanganate (KMn04) will also oxidize primary alcohols to carboxylic acids. What is the oxidation state of manganese in KMn04 ... 

Carboxylic acids can be prepared by oxidizing primary alcohols and aldehydes with a strong oxidizing agent, such as acidified aqueous potassium permanganate solution. In some cases, an alkyl group can be oxidized directly to a carboxyl group. This process is very important industrially. 

Primary and secondary alcohols are oxidized slowly at low temperatures by benzyltriethylammonium permanganate in dichloromethane primary alcohols produce methylene esters (60-70%), resulting from reaction of the initially formed carboxylate anion with the solvent, with minor amounts of the chloromethyl esters and the carboxylic acids. Secondary alcohols are oxidized (75-95%) to ketones [34] the yields compare favourably with those obtained using potassium permanganate on a solid support. 1,5-Diols are oxidized by potassium permanganate under phase-transfer catalytic conditions to yield 8,8-disubstituted-8-valerolactones [35] (Scheme 10.1). 

Acidified potassium permanganate solution, KMn04(aq), acts as an oxidizing agent when it comes in contact with alcohols. In this investigation, you will discover how potassium permanganate reacts with a primary, a secondary, and a tertiary alcohol. 

Primary alcohols are readUy oxidised to carboxylic acids with common oxidising agents such as potassium permanganate (KMn04) in neutral, acidic or alkaline media or by potassium dichromate (K2Cr207) and chromium trioxide (CrOg) in acidic media (Jones reagent). 

Compounds containing susceptible C—H bonds can be oxidized to alcohols.134 Nearly always, the C—H bond involved is tertiary, so the product is a tertiary alcohol. This is partly because tertiary C—H bonds are more susceptible to free-radical attack than primary and secondary bonds and partly because the reagents involved would oxidize primary and secondary alcohols further. In the best method the reagent is ozone and the substrate is absorbed on silica gel.135 Yields as high as 99% have been obtained by this method. Other reagents, which often give much lower yields, are chromic acid,136 alkaline permanganate,137 potassium... 

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]. 

Permanganate ion, Mn04G, oxidizes both primary and secondary alcohols in either basic or acidic solution. With primary alcohols the product normally is the carboxylic acid because the intermediate aldehyde is oxidized rapidly by permanganate ... 

Primary and secondary alcohols are readily oxidized by permanganate while tertiary alcohols are stable.284,311 Primary alcohols are transformed into carboxylic acid via the formation of aldehydes. Secondary alcohols are cleanly oxidized to ketones.294... 

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