Addition of hydrogen peroxide

Aqueous solutions containing titanium(IV) give an orange-yellow colour on addition of hydrogen peroxide the colour is due to the formation of peroxo-titanium complexes, but the exact nature of these is not known. 

Addition of hydrogen peroxide to a solution of a dichromate yields the blue colour of "peroxochromic acid. This is a test for soluble chromates and dichromates. 

Analytical Methods. A classical and stiU widely employed analytical method is iodimetric titration. This is suitable for determination of sodium sulfite, for example, in boiler water. Standard potassium iodate—potassium iodide solution is commonly used as the titrant with a starch or starch-substitute indicator. Sodium bisulfite occurring as an impurity in sodium sulfite can be determined by addition of hydrogen peroxide to oxidize the bisulfite to bisulfate, followed by titration with standard sodium hydroxide (279). 

YeUowing of wool can occur during dyeing, depending on pH, temperature and time, and chlorinated wools ate especially sensitive. Bleaching agents that can be added to the dyebath have been developed based on sodium bisulfite and hydroxylamine sulfate (108). Addition of hydrogen peroxide to the dyebath after exhaustion can also be effective. 

The preparation of neopentyl alcohol from diisobutylene herein described represents an example of acid-catalyzed addition of hydrogen peroxide to a branched olefin, followed by an acid-catalyzed rearrangement of the tertiary hydroperoxide formed. In addition to neopentyl alcohol, there are formed acetone and also small amounts of methanol and methyl neopentyl ketone by an alternative rearrangement of the hydroperoxide. 

Formaldehyde, benzaldehyde and aniline react violently with 90% performic acid (Ref 1). An unspecified organic compd was added to the acid, and soon after the initial vigorous reaction had subsided, the mixt expld violently (Ref 3). Reaction with aikenes is vigorously exothermic, and adequate cooling is necessary. Reactions with performic acid can be more safely accomplished by the slow addition of hydrogen peroxide to a soln of the compd in formic acid (Ref 4)... 

The oxidation is autocatalytic, being catalyzed by the product, benzeneseleninic acid. If the temperature drops significantly below 30°, the addition of hydrogen peroxide should be stopped, and the ice-salt bath should be removed to maintain the rate of oxidation and avoid an accumulation of hydrogen peroxide in the flask. 

A bi-enzymatic system (glucose oxidase -I- HRP) was also used to catalyze the synthesis of phenolic polymers. The polymerization of phenol, albeit in moderate yield, was accomplished in the presence of glucose avoiding the addition of hydrogen peroxide (Scheme 2 ), which was formed in situ by the oxidation of glucose catalyzed by glucose oxidase. 

Direct addition of hydrogen peroxide or organic peroxides Exposure to autoxldizing agents (e.g. 

Krishnamurty, K. V. et al., At. Abs. Newslett., 1976, 15, 68-70 When preparing soil and sediment samples for atomic absorption spectral analysis for trace metals, pre-oxidation with nitric acid before addition of hydrogen peroxide eliminates the danger of explosion. 

Lucigenin produces a weak light in an alkaline solution, and the intensity of its light is substantially increased by the addition of hydrogen peroxide [49], As to the reaction mechanism, it has been postulated [50, 51] that lucigenin is oxidized to form a peroxide, which is then decomposed to yield an excited state of A-methylacridine, as shown in Figure 6. 

Phenol formed in the system due to acid-catalyzed decomposition of hydroperoxide retards the cumene oxidation. The aqueous phase withdraws phenol from the hydrocarbon phase. This is the reason why the emulsion oxidation of cumene helps to increase the yield of hydroperoxide. The addition of hydrogen peroxide into the system helps to increase the yield of hydroperoxide. 

The oxidation of primary and secondary alcohols in the presence of 1-naphthylamine, 2-naphthylamine, or phenyl-1-naphthylamine is characterized by the high values of the inhibition coefficient / > 10 [1-7], Alkylperoxyl, a-ketoperoxyl radicals, and (3-hydroxyperoxyl radicals, like the peroxyl radicals derived from tertiary alcohols, appeared to be incapable of reducing the aminyl radicals formed from aromatic amines. For example, when the oxidation of tert-butanol is inhibited by 1-naphthylamine, the coefficient /is equal to 2, which coincides with the value found in the inhibited oxidation of alkanes [3], However, the addition of hydrogen peroxide to the tert-butanol getting oxidized helps to perform the cyclic chain termination mechanism (1-naphthylamine as the inhibitor, T = 393 K, cumyl peroxide as initiator, p02 = 98 kPa [8]). This is due to the participation of the formed hydroperoxyl radical in the chain termination ... 

PAL [peroxide assisted leach] An improved cyanide process for extracting gold from its ores. Addition of hydrogen peroxide to the system improves the yield of gold and reduces the usage of cyanide. First operated in South Africa in 1987. 

FoS had obvious antioxidant effect. In cell-free system after the addition of hydrogen peroxide solution the extinguishing of fluorescence of 2 ,7 -dichlorofluo-rescein was evident with H202 concentrations at 97 and 194pM. At the substantially higher concentration of the latter (970 pM) a slight nonsignificant overlap of control level was evident (Fig. 7.2). These data confirm the antioxidant activity of pristine C60. On the other hand, they indicate that it is limited to a certain antioxidant capacity (Fig. 7.2). 

The rate of addition of hydrogen peroxide is fairly fast initially but is slowed to maintain the indicated temperature. It is important to get the reaction over in a short time (5-7 minutes) for the best yield. 

The early work on catalase expression was carried out largely in E. coli and revealed two main response mechanisms. One or the other or both responses have been identified in most other bacteria expressing a catalase. The expected and most obvious response is to oxidative stress. Addition of hydrogen peroxide directly or of ascorbate, which... 

O3yhydroperoxides. Peroxides of the oxyhydro type are obtained by the addition of hydrogen peroxide to ketones. High yields of alkyl radicals are then often obtained by reaction with ferrous salts. 1-Meth-oxycyclohexyl hydroperoxide is easily obtained from cyclohexanone and hydrogen peroxide in methanol. It gives rise to the 5-(methoxy-carbonyl)-pentyl radical, which has been used to alkylate protonated heteroaromatic bases in high yield [Eq. (6)]. 

Another interesting dialkylperoxide explosive, which probably has the structure of (47), is synthesized by the addition of hydrogen peroxide and nitric acid to a solution of urea and formaldehyde. ... 

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