Peroxides, preparation

Zinc, calcium, and magnesium peroxides prepared from hydrogen peroxide are used as specialized oxidants where a slow release of hydrogen peroxide is desired. These find use in various medicinal treatments. 

Martin, G.P. and Nokhodchi, A. (2006) The microsponge delivery system of benzoyl peroxide preparation, characterization and release studies. International Journal of Pharmaceutics, 308, 124-132. 

SCHEME 30. Preparation of symmetrical dialkyl peroxides TABLE 7. Yields of dialkyl peroxides prepared by different methods... 

Alkyl hydroperoxides can form 2 1 adducts with DABCO. Both nitrogens of DABCO are involved and the resulting adduct contains 2 mol of hydroperoxide per mol of DABCO. Table 4 lists the silyl alkyl peroxides prepared using the DABCO-hydroperoxide adduct techniques. 

Bis(silyl) peroxide, preparation, 776-7 Bis(stannyl)peroxide, peroxide transfer reaction, 825... 

Chlorotetramethyldisiloxane, preparation, 781 Chlorotriorganosilanes, silyl peroxide preparation, 779-83... 

It was not possible to determine the composition of the peroxide by microanalysis since samples tended to explode at room temperature however, it was possible to measure the atomic ratio of chlorine to oxygen in a concentrated solution in toluene of peroxide prepared by oxidation to 10 mole % at 35°C. This ratio was 0.51, close to that required by the repeating unit (C4H5C10o)w. 

When the NMR spectrum of a 30% (w./v.) solution of peroxide in toluene was recorded at 34°C., absorption was observed between 8 2.74 and 5.46. There were seven main resonances, all multiplets, which were interpreted in terms of aliphatic hydrogen shifted by oxygen. Resonance from ethylenic hydrogen amounted to only a fraction of a proton. However, the sample darkened while in the instrument and probably decomposed extensively. When the spectrum of a solution of peroxide prepared by oxidation to 10.4 mole % was recorded using a cold probe at —35°C. a different picture was obtained. There was complex absorption from both ethylenic and saturated hydrogen which was interpreted as arising from a mixture of 1,2 and 1,4 oxygen copolymers in an approximate jatio of 1 to 2. In this sample the residual chloroprene amounted to 0.15% of the monomer units in the peroxide and dimers of chloroprene to 0.6% of the peroxide. 

Applying the method to double-labeling studies used acetyl peroxide prepared from acetic anhydride with a high level of labeling (3.57 atom % excess 180). A sample of this peroxide was recovered after heating at 80°C. for 8700 sec. The oxygen derived from this peroxide showed a... 

Carotanes -m peroxide preparation [PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) -m petroleum [PETROLEUM - COMPOSITION] (Vol 18)... 

Kametani et al. have studied the biotransformations of TV-methyl-homococlaurine (130) and homoorientaline (138) by peroxidase enzyme preparations (100, 111, 112). The peroxidase activity of a potato peel homogenate-hydrogen peroxide preparation resulted in dimer and trimer formation when benzylisoquinolines were used as substrate (Section IV, C), and... 

Acetyl peroxide decomposes explosively when heated rapidly above its melting point, and it must be handled with extreme caution at ordinary temperature. According to Kuhn, Chem. Eng. News., 26, 3197 1948), acetyl peroxide prepared by this method should be used within 24 hours of its preparation, and the preparation itself should be completed without interruption. 

Direct homolytic carboxylation of pyrazine cation has been described. A solution of ethyl pyruvate and hydrogen peroxide prepared at — 10° with a solution of aqueous ferrous sulfate and pyrazine in aqueous sulfuric acid gave 2-ethoxycarbonyl-pyrazine and diethoxycarbonylpyrazine (1358). 

Conjugated dienes (and compounds that behave like conjugated dienes in the Diels-Alder reaction) react with singlet oxygen to form cyclic peroxides as if molecular oxygen acted as a dienophile. The yields of the peroxides, prepared by photochemical oxidation [13, 55] or by chemical oxidations with hydrogen peroxide and sodium hypochlorite, alkaline hydrogen peroxide and bromine, alkaline salts of peroxy acids [14, 26], or the ozonide of triphenyl phosphite [29], are comparable. 

Nickel peroxide, prepared by adding an alkaline solution of 6% sodium hypochlorite to a solution of nickel sulfate hydrate at 20 °C, is used to oxidize alcohols to carbonyl compounds or carboxylic acids. The oxidation... 

Thiboutot D, Jarratt M, Rich P, Rist T, Rodriguez D, Levy S. A randomized, parallel, vehicle-controlled comparison of two erythromycin/benzoyl peroxide preparations for acne vulgaris. Qin Ther 2002 24(5) 773-85. 

The reaction of ozone with strontium peroxide prepared in Freon 12 below 0 °C is reported to produce strontium ozonide, Sr(03)2, and strontium superoxide, Sr(02)2. The ozonide forms only below —70°C and neither... 

Salicylic acid is a mild irritant and similar precautions should be adopted as for benzoyl peroxide. Preparations are applied twice or three times a day. Salicylic acid is readily absorbed through the skin and excreted slowly, and salicylate poisoning can occur if preparations are applied frequently, in large amounts and over large areas. Patients who are sensitive to aspirin should avoid these preparations. 

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