Hydrogen peroxide action

Hydrogen peroxide, action on carbohydrates and related compounds, 19, 149-179 Hydrolysis,... 

Saponification in the presence of sodium, potassium, ammonium, or calcium hydroxides is performed between 40 and 100°C for 1-4 h. The amount of alkali used to treat 100 g/L wheat bran ranges from 0.5 to 2.0 mol/L. Saponification breaks mainly ester bonds with ferulic acid, which dissolves the chains of arabi-noxylans. The yield of soluble hemicellulose is 20% [7] to 70% [8] if completed by hydrogen peroxide action. Complementary acid hydrolysis is required when monomeric sugars are targeted. 

By the 5th day, infusorians incubated in hydrogen peroxide died. Adding of ascorbic acid (1 tM) to the cell medium subjected to hydrogen peroxide action almost two-fold increased the ninnber of species in the first 24 hours. At the same time, ascorbic acid prevented death of culture cells that was noted in all test days (Figs. 3.2 and 3.3). 

By the action of an alkaline solution of hydrogen peroxide upon the corresponding nitrile, for example ... 

Thiazole-N-oxides are prepared by the action at low temperature (-10°C) of hydrogen peroxide in acetic acid (474). 4-MethyIthiazole and 2,4-dimethylthiazole afforded the corresponding N-oxides with yields of 27 and 58%, respectively (Scheme 88). Thiazole-N-oxides without a methyl group in the 2-position are so unstable that they have a tendency to form 2-hydroxythiazoles and are decomposed by oxidation, whereas a 2-methyl group would prevent such rearrangement (474). 

Hydrogen peroxide may react directiy or after it has first ionized or dissociated into free radicals. Often, the reaction mechanism is extremely complex and may involve catalysis or be dependent on the environment. Enhancement of the relatively mild oxidizing action of hydrogen peroxide is accompHshed in the presence of certain metal catalysts (4). The redox system Fe(II)—Fe(III) is the most widely used catalyst, which, in combination with hydrogen peroxide, is known as Fenton s reagent (5). 

The direct conversion of aniline into aminophenols may be achieved by hydrogen peroxide hydroxylation in SbE —HE at —20 to —40° C. The reaction yields all possible aminophenols via the action of H20" 2 on the anilinium ions the major product is 3-aminophenol (64% yield) (70,71). This isomer may also be made by the hydrolysis of 3-aminoaniline [108-45-2] in dilute acid at 190°C (72). Another method of limited importance, but useful in the synthesis of derivatives, is the dehydrogenation of aminocyclohexenones (73). 

D,L-Arahinitol can be prepared by the action of hydrogen peroxide in the presence of formic acid on divinyl carbinol (36) and, together with ribitol (Fig. ld),fromD,L-erythron-4-pentyne-l,2,3-triol,HOCH2CHOHCHOHC=CH (37). 

The action of hydrogen peroxide on freshly precipitated hydrated Ti(IV) oxide or the hydrolysis of a peroxide compound such as K2[Ti(02)(S0 2] yields, after drying, a yellow soHd, stable below 0°C, of composition TiO 2H2O. There is one peroxo group per titanium, but the precise stmcture is not known. The yellow soHd loses oxygen and water when heated and Hberates chlorine from hydrochloric acid. When freshly prepared, it is stable in acid or alkah, giving peroxy salts. 

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

Figure S.l The enzyme superoxide dismutase (SOD). SOD is a P structure comprising eight antiparallel P strands (a). In addition, SOD has two metal atoms, Cu and Zn (yellow circles), that participate in the catalytic action conversion of a superoxide radical to hydrogen peroxide and oxygen. The eight p strands are arranged around the surface of a barrel, which is viewed along the barrel axis in (b) and perpendicular to this axis in (c). [(a) Adapted from J.S. Richardson. The stmcture of SOD was determined in the laboratory of J.S. and D.R. Richardson, Duke University.)...

The hydrogen peroxide produced in the glucose oxidase catalyzed reaction has an antibacterial action. If the presence of hydrogen peroxide is undesirable in the product, catalase is added to remove the peroxide. 

A dimer is formed by the action of hydrogen peroxide on the quaternary salt of 3,4-dihydroisoquinoline (235). The other similar reactions are of small importance. 

The reaction is reversible and (24) can be recovered by the action of hydrogen peroxide. 

The action of ferric chloride and hydrogen peroxide on isopropyli-dene and benzylidene derivatives of 2-hydrazinoselenazole yields deeply colored compounds of the 2,2 -dioxo-A -biselenazol-5,5 -inylidene bis-hydrazone type. (Cf. Table VIII.)... 

A mixture of hydrochloric and nitric acids (3 1 by volume) known as aqua regia is a very potent solvent largely due to its oxidising character, and the addition of oxidants such as bromine or hydrogen peroxide frequently increases the solvent action of acids. 

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