Peroxides peroxy acids

Hydroperoxides Organomineral Hydroperoxides a-Oxy and a-Peroxy-Hydroperoxides and Peroxides Ozonides Peroxides Peroxy Acids Diacyl Peroxides Peroxy Esters and Poly Peroxides... 

Hydrogen peroxide reacts with some acids (sulphuric acid for instance) and forms peroxy-acida, and with some bases [such as Ca(OH2), Ba(OH)2, Mg(OH)2, Zn(OH)2] and forms peroxides. Oxides of the IV and VI group of the periodic system (i. e. oxides of Ce, Ti, V, Nb, Ta, Cr, Mo, W, U) also react with hydrogen peroxide to form peroxides, peroxy-acids and persalts. Many additive compounds of hydrogen peroxide are known such as with sodium metaborate, urea and hexamethylene-tetramine. 

Nitroso compounds are readily oxidized to the corresponding nitro compounds by peroxides, peroxy acids, oxygen, ozone and dinitrogen tetroxide. ... 

The oxidation reagents used most frequently for the conversion of sulfides into sulfoxides and sulfones are hydrogen peroxide, peroxy acids, and periodates. Periodates usually do not oxidize sulfoxides to sulfones [770 771, 772, 776, 775], In addition, many other, even rather exotic, oxidants have been used especially for chemoselective oxidations of sulfides containing functional groups vulnerable to attack by peroxy compounds, such as double bonds and carbonyl groups. 

Selenoxides are useful intermediates in the preparation of a,3-unsat-urated carbonyl compounds and esters. The treatment of aldehydes, ketones, or esters with benzeneselenyl chloride, C6H5SeCl, followed by the oxidation of the selenides to selenoxides by hydrogen peroxide, peroxy acids, or sodium periodate, gives a,3-unsaturated aldehydes, ketones, or esters. Thus, dehydrogenation with the formation of a carbon-carbon double bond is accomplished under very mild conditions [167, 169] (equation 593). 

Primary amines are oxidized to hydroxlyamines, which in turn are oxidized to ni-troso compounds, which are oxidized to nitro compounds. Hydrogen peroxide, peroxy-acids, and other common oxidizing agents are used to oxidize amines. The oxidation reactions generally take place by mechanisms that involve radicals, so they are not well characterized. 

The oxidative workup used to produce acids from ozonides such as 349 uses reagents such as hydrogen peroxide, peroxy acids, silver oxide, chromic acid or permanganate. The conversion of cyclohexene to adipic acid by treatment with (1) O3 and (2) H2O2 is a simple example of a typical oxidative workup. When the ozonide is disubstituted (two carbon groups on the initial carbon of the alkene), the product is a ketone and... 

Ozonation of Heteroatoms. Phosphines are converted to phosphine oxides and phosphites to phosphates by ozone. These reactions are quite general and a wide range of sub-stitutents can be tolerated. Phosphine oxides also can be produced by the ozonation of alkylidenetriphenylphosphoranes or of thio- or selenophosphoranes. Organic sulfides are converted to sulfoxides and sulfones by ozonation. Tertiary amines are converted to amine oxides, while nitro compounds can be produced in modest yields by ozonation of primary amines. This preparation of nitroalkanes compares well with alternate approaches using peroxides, peroxy acids, permanganate, or Monoperoxysulfuric Acid, but ozonation on silica gel has proven to be superior (see Ozone-Silica Get). Selenides are converted to selenoxides by ozone and this reaction is often used to achieve overall production of unsaturated carbonyl compounds. An example is shown in eq 25. ... 

Peroxy acids and diacyl peroxides are mono- and di-acyl derivatives of hydrogen peroxide. Peroxy acids form esters of which the t-butyl compounds are the best known. In contrast to carboxylic acids which form intermolecular hydrogen-bonded dimers, the peroxy acids exist as intramolecular hydrogen-bonded monomers. This leads to several differences in the properties of these two types of acids. 

One equivalent of a peroxy acid or of hydrogen peroxide converts sulfides to sulf oxides two equivalents gives the corresponding sulfone... 

Section 16 16 Oxidation of sulfides yields sulfoxides then sulfones Sodium metaper lodate IS specific for the oxidation of sulfides to sulfoxides and no fur ther Hydrogen peroxide or peroxy acids can yield sulfoxides (1 mole of oxidant per mole of sulfide) or sulfone (2 moles of oxidant per mole of sulfide)... 

Conversion of Aromatic Rings to Nonaromatic Cyclic Structures. On treatment with oxidants such as chlorine, hypochlorite anion, chlorine dioxide, oxygen, hydrogen peroxide, and peroxy acids, the aromatic nuclei in lignin typically ate converted to o- and -quinoid stmctures and oxinane derivatives of quinols. Because of thein relatively high reactivity, these stmctures often appear as transient intermediates rather than as end products. Further reactions of the intermediates lead to the formation of catechol, hydroquinone, and mono- and dicarboxyhc acids. 

Safety. Since organic peroxides can be initiated by heat, mechanical shock, friction or contamination, an enormous problem in safety presents itself. Numerous examples of this problem have already been shown in this article. Additional examples include the foilowing methyl and ethyl hydroperoxides expld violently on heating or jarring, and their Ba salts also are extremely expl the alkylidene peroxides derived from low mw aldehydes and ketones are very sensitive and expld with considerable force polymeric peroxides of dimethyl ketene, -K>-0-C(CH3)2C(0)j-n, expld in the dry state by rubbing even at —80° peroxy acids, especially those of low mw, and diacetyl, dimethyl, dipropkmyl and methyl ethyl peroxides, when pure, must be handled only in small amts and... 

The great utility of hydrogen peroxide as a reagent for the conversion of sulphoxides to sulphones spurred the investigation of other peroxy-containing compounds. Probably the most commonly used species is peracetic acid which is formed by the reaction of acetic acid with hydrogen peroxide. In addition, other peroxy acids such as pertrifluoroacetic acid and m-chloroperbenzoic acid and hydroperoxides and hydrotrioxides are often used to convert sulphoxides to sulphones. 

Numerous methods of preparing peroxy acids are described in the literature,2 3 and many of them have been applied to the synthesis of peroxybenzoic acid. A common way of preparing it has been by the action of sodium methoxide on benzoyl peroxide followed by acidification.3 The present method is adapted from one in a recent publication.4... 

Oxidation, of acids to peroxy acids by hydrogen peroxide, 43, 96 of alkylarenes to aromatic carboxylic acids, 43, 80... 

Peroxides, test for, 41, 92 Peroxy acids from carboxylic acids and 70% hydrogen peroxide, 43, 96 Peroxybenzoic acid, 43,93 iodometric analysis of, 43, 94 Peroxystearic acid, 43,96 Phenacylamine hydrochloride, 41, 82... 

The preparation of Pans-1,2-cyclohexanediol by oxidation of cyclohexene with peroxyformic acid and subsequent hydrolysis of the diol monoformate has been described, and other methods for the preparation of both cis- and trans-l,2-cyclohexanediols were cited. Subsequently the trans diol has been prepared by oxidation of cyclohexene with various peroxy acids, with hydrogen peroxide and selenium dioxide, and with iodine and silver acetate by the Prevost reaction. Alternative methods for preparing the trans isomer are hydroboration of various enol derivatives of cyclohexanone and reduction of Pans-2-cyclohexen-l-ol epoxide with lithium aluminum hydride. cis-1,2-Cyclohexanediol has been prepared by cis hydroxylation of cyclohexene with various reagents or catalysts derived from osmium tetroxide, by solvolysis of Pans-2-halocyclohexanol esters in a manner similar to the Woodward-Prevost reaction, by reduction of cis-2-cyclohexen-l-ol epoxide with lithium aluminum hydride, and by oxymercuration of 2-cyclohexen-l-ol with mercury(II) trifluoro-acetate in the presence of ehloral and subsequent reduction. ... 

The data in Tables 19 and 20 show that both peroxysulphuric and peroxyacetic acid give the induced reduction of hydrogen peroxide by thiocyanate. The induced reduction depends strongly on the pH of the solution and on the concentration of thiocyanate. At pH > 3 both peroxy acids reacts more slowly... 

On the basis of these results it can be stated that the fast oxidation of thiocyanate by peroxy acids gives rise to the induced reduction of hydrogen peroxide. In order to elucidate the mechanism of this interesting reaction let us have a look at reactions of thiocyanate with peroxy compounds of different types. 

The reactions of peroxysulphuric acid and of hydrogen peroxide with the thiocyanate are obviously very similar. In both reactions the reactive intermediate is the same or at least has a very similar structure, and the subsequent reactions of this entity are equally fast either with peroxy acid or with hydrogen peroxide. Accordingly it can be said that if both peroxy acid and hydrogen peroxide are present in the solution a competition between these two substances for the intermediate occurs, as a result of which not only the peroxy acid but also the hydrogen peroxide will be reduced. 

In solutions of pH > 3, when the rate of reduction of peroxy acid is much lower, the induced disappearance of hydrogen peroxide will be considerably reduced. 

---