Hydrogen peroxide aqueous solutions, concentration

The ammonium hydrogensulphate is returned to the electrolytic cell. A process such as this yields an aqueous solution containing about 30% hydrogen peroxide. The solution can be further concentrated, yielding ultimately pure hydrogen peroxide, by fractional distillation but the heating of concentrated hydrogen peroxide solutions requires care (see below). 

Eatty amine oxides are most frequendy prepared from alkyldimethylarnines by reaction with hydrogen peroxide. Aqueous 2-propanol is used as solvent to prepare amine oxides at concentrations of 50—60%. With water only as a solvent, amine oxides can only be prepared at lower concentrations because aqueous solutions are very viscous. Eatty amine oxides are weak cationic surfactants. 

In the absence of a catalyst, the disproportionation is too slow to be observed at room temperature. Rapid, exothermic, and potentially explosive decomposition of hydrogen peroxide is initiated, however, by heat and by a broad range of catalysts, including transition metal ions, certain anions (such as I-), metal surfaces, blood (Figure 14.9), and even tiny particles of dust. Because decomposition is accelerated by light, hydrogen peroxide is stored in dark bottles. It is best handled in dilute aqueous solutions concentrated solutions and the pure liquid are extremely hazardous materials. 

Because of the instability of pure and concentrated aqueous solutions of hydrogen peroxide, it is usually used in dilute solution. The concentration of such solutions is often expressed in terms of the volume of oxygen evolved when the solution decomposes ... 

In what way does a solution of hydrogen peroxide react with (a) chlorine water, (b) potassium permanganate solution, (c) potassium dichromate solution, (d) hydrogen sulphide 50 cm of an aqueous solution of hydrogen peroxide were treated with an excess of potassium iodide and dilute sulphuric acid the liberated iodine was titrated with 0.1 M sodium thiosulphate solution and 20.0 cm were required. Calculate the concentration of the hydrogen peroxide solution in g 1" ... 

The study of the chemical behavior of concentrated preparations of short-Hved isotopes is compHcated by the rapid production of hydrogen peroxide ia aqueous solutions and the destmction of crystal lattices ia soHd compounds. These effects are brought about by heavy recoils of high energy alpha particles released ia the decay process. 

Neutralizing Lotion. The principal active ingredient of cold wave neutralizers is usually an oxidizing agent. The most popular is hydrogen peroxide [7722-84-1J, employed at a concentration of 1—2% it continues to find widespread use. Aqueous solutions of sodium bromate [7789-38-0] at a concentration of 10—20% occasionally are used and are technically preferred over the peroxide formulations because of excellent stabiUty and absence of hair bleaching. Neutralizing powders appear to be on the decline but formulations stiU in use consist of sodium perborate [7632-04-4] combined with hexametaphosphates to improve solubiUty in hard water. 

In aqueous solution, all the sodium peroxoborates dissociate for the most part into boric acid, or its anion, and hydrogen peroxide. Peroxoborate species are also present in these solutions, depending on the pH and the concentration for the species type. The nature of these species has been extensively examined by classical physicochemical methods (13), by nmr, and by Raman spectroscopy (14—17). Both monomeric and polymeric species are usually present. There is some evidence (18) suggesting that these peroxoborates are more reactive than hydrogen peroxide alone under similar conditions. 

The pure peroxoacid, prepared at —80°C, decomposes explosively at —30°C. Solutions in acetic acid or water of below the limiting concentration (corresponding to a stoicheiometric mixture of 70% aqueous nitric acid and 100% hydrogen peroxide) are stable, while those above the limit decompose autocatalytically, eventually exploding [1], Explosion of the vapour when passed into a mass spectrometer inlet at 427°C (but not at 327°) was noted [2],... 

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