Ketones oxidation products

Carlsson and Wiles have in an early work (14) discussed the ketonic oxidation products of PP films. The volatile products were analysed in GC with a flame ionization detector (FID) and a thermal conductivity detector (TCD) giving the major oxidation products carbon monoxide and acetone. Other products detected were water, formaldehyde, formic acid, propane, acetic acid and iso-propylalcohol. 

Table VI. Rates of Methyl Ethyl Ketone Oxidation Products" Formed by Bimolecular (W2) and Unimolecular (Wi) Routes in Reaction Involving R02 in Benzene Solution (145°C., 50 atm.)...

When methyl ethyl ketone is oxidized in aqueous solutions, the over-all reaction rate drops because of solvation of the peroxy radicals, and w1 decreases more than w2. The reaction rates for formation of methyl ethyl ketone oxidation products in aqueous solutions are shown, as an example, in Tables VII and VIII. 

Melochinine (22) has been correlated with cassine (23) by transformation into the pyridine ketone (24), obtainable by dehydrogenation of cassine. It follows that the ring substituents in the two alkaloids have the same arrangement (Scheme 6).32 Other constituents of the leaves of Melochia pyramidata L. include melochinine D-glucoside and melochinone [the ketonic oxidation product of (22)].33... 

The catalytic cycle involving [RuCbCPPhsjs], one of the more active transfer-hydrogenation catalysts, is shown in Scheme 10. The catalyst first forms an alkoxido complex, with elimination of HCl, when allowed to react with the secondary alcohol. This pentacoordinate complex forms an 18-electron species by coordinating a molecule of alkene. The alkoxido ligand transfers its Q -deuterium atom to the metal, after which the ketone oxidation product of the secondary alcohol is eliminated. The steps are believed to occur in... 

Carbohydrates are aldehyde or ketone oxidation products of normal poly-hydroxy alcohols of the same number of carbon atoms, in which one carbon group only is oxidized to aldehyde or ketone, the aldehyde group being the end carbon group and the ketone group being next to the end. 

Polypropylene usually exhibits an ultraviolet absorption extending beyond 290 nm, although the pure polymer is not expected to show an absorption beyond 200 nm. Photodegradation of polypropylene is thus likely to be initiated by impurities such as hydroperoxides or ketonic oxidation products formed during the processing of the sample. Such behaviour is similar to that already discussed for polyethylene. 

Oxidation begins with the breakdown of hydroperoxides and the formation of free radicals. These reactive peroxy radicals initiate a chain reaction that propagates the breakdown of hydroperoxides into aldehydes (qv), ketones (qv), alcohols, and hydrocarbons (qv). These breakdown products make an oxidized product organoleptically unacceptable. Antioxidants work by donating a hydrogen atom to the reactive peroxide radical, ending the chain reaction (17). 

Acids are usually the end products of ketone oxidations (41,42,44) but vicinal diketones and hydroperoxyketones are apparent intermediates (45). Acids are readily produced from vicinal diketones, perhaps through anhydrides (via, eg, a Bayer-ViUiger reaction) (46,47). The hydroperoxyketones reportedly decompose to diketones as well as to aldehydes and acids (45). Similar products are expected from radical— radical reactions of the corresponding peroxy radical precursors. 

McGarry, J. D., and Foster, D. W., 1980. Regulation of hepatic fatty acid oxidation and ketone body production. Annual Review of Biochemistry 49 395-420. 

Roussel lijs studied ilie oxidation products of cedrenc, from which he obtained the ketone eedrone, C,5lJ., 0, by means of chromic acid. On rediKitlon ihis yields an alcohol, isocedrol, isomeric with cedrol,... 

The mixture of n-hutenes (1- and 2-hutenes) could he oxidized to different products depending on the reaction conditions and the catalyst. The three commercially important oxidation products are acetic acid, maleic anhydride, and methyl ethyl ketone. 

Figure 18-10 summarizes the successive oxidation products that can be obtained from alcohols. When the hydroxyl group, OH, is attached on an end carbon atom, an aldehyde and a carboxylic acid can be obtained through oxidation. When the hydroxyl group is on a carbon atom attached to two other carbon atoms, oxidation gives a ketone. Huge amounts of aldehydes and ketones are used industrially in a variety of chemical processes. Furthermore, these functional groups are important in chemical syntheses of medicines, dyes, plastics, and fabrics. 

Predict the oxidation products of aldehydes and ketones (Section 19.5). 

Alkenes have also been converted to more highly oxidized products. Examples are (1) Treatment with KMn04 in aqueous acetone containing acetic acid gives a-hydroxy ketones. (2) 1,2-Disubstituted and trisubstituted alkenes give a-chloro ketones when oxidized with chromyl chloride in acetone RCH=CR R"—> RCOCCIR R". (3) a-Iodo ketones can be prepared by treating alkenes with... 

Thirdly, if it is not possible to apply the SRS technique, it can be established whether a primary, secondary or tertiary alcohol is present by oxidizing the alcohol on the chromatographic zone and then subjecting the oxidation product to a detection reaction. On oxidation primary alcohols form aldehydes, secondary alcohols ketones and tertiary alcohols are not oxidized. 

The hydrogen transfer reaction (HTR), a chemical redox process in which a substrate is reduced by an hydrogen donor, is generally catalysed by an organometallic complex [72]. Isopropanol is often used for this purpose since it can also act as the reaction solvent. Moreover the oxidation product, acetone, is easily removed from the reaction media (Scheme 14). The use of chiral ligands in the catalyst complex affords enantioselective ketone reductions [73, 74]. 

Increased fatty acid oxidation is a characteristic of starvation and of diabetes meUims, leading to ketone body production by the Ever (ketosis). Ketone bodies are acidic and when produced in excess over long periods, as in diabetes, cause ketoacidosis, which is ultimately fatal. Because gluconeogenesis is dependent upon fatty acid oxidation, any impairment in fatty acid oxidation leads to hypoglycemia. This occurs in various states of carnitine deficiency or deficiency of essential enzymes in fatty acid oxidation, eg, carnitine palmitoyltransferase, or inhibition of fatty acid oxidation by poisons, eg, hypoglycin. 

Inspired by Gif or GoAgg type chemistry [77], iron carboxylates were investigated for the oxidation of cyclohexane, recently. For example, Schmid and coworkers showed that a hexanuclear iron /t-nitrobenzoate [Fe603(0H) (p-N02C6H4C00)n(dmf)4] with an unprecedented [Fe6 03(p3-0)(p2-0H)] " core is the most active catalyst [86]. In the oxidation of cyclohexane with only 0.3 mol% of the hexanuclear iron complex, total yields up to 30% of the corresponding alcohol and ketone were achieved with 50% H2O2 (5.5-8 equiv.) as terminal oxidant. The ratio of the obtained products was between 1 1 and 1 1.5 and suggests a Haber-Weiss radical chain mechanism [87, 88] or a cyclohexyl hydroperoxide as primary oxidation product. 

The Pacman catalyst selectively oxidized a broad range of organic substrates including sulfides to the corresponding sulfoxides and olefins to epoxides and ketones. However, cyclohexene gave a typical autoxidation product distribution yielding the allylic oxidation products 2-cyclohexene-l-ol (12%) and 2-cyclohexene-1-one (73%) and the epoxide with 15% yield [115]. 

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