Hydrogen peroxide, 90% concentration

The decomposition of aqueous hydrogen peroxide is minimized by various purification steps during manufacture, use of clean passive equipment, control of contaminants, and the addition of stabilizers. The decomposition is zero-order with respect to hydrogen peroxide concentration. 

Hydrogen peroxide concentrations of 35% and above may, and 50% and above do, cause spontaneous combustion of dry grasses, wood, and leaves. Spills of concentrated hydrogen peroxide should be diluted with excess amounts of water immediately. Practically all soHd combustible materials contain sufficient quantities of catalytic impurities to rapidly decompose hydrogen peroxide, especially at 70% concentration and above. 

The reaction in equation 55 occurs when there is insufficient hydrogen peroxide reductant in the absorber solution. Monitoring of the hydrogen peroxide concentration is important because is unstable in strong alkaline solutions, decomposing to water and oxygen. A small excess of sodium hydroxide is... 

Cotton linters and viscose grade wood pulp were grafted with acrylamide using the xanthate method. The effects of monomer concentration, reaction time, hydrogen peroxide concentration, reaction temperature, and liquor ratio on the grafting process were studied. Optimum conditions for the grafting reaction were established [26]. 

Figure 5 Effect of hydrogen peroxide concentration on grafting yield and grafting efficiency, wood pulp.

For determination of low hydrogen peroxide concentrations, a chemiluminescent reagent system was developed consisting of oxalyldiimidazole and an immobilized fluorophore (3-aminofluoranthene) on an acrylate polymer.[47]... 

Fig. 14.13 (a) Bubble temperatures estimated using the MRR method as a function of thermal conductivity for the rare gases, (b) Hydrogen peroxide concentration following sonication of pure water as a function of gas solubility in different rare gases ( ) He ( ) Ne (a) Ar ( ) Kr ( ) Xe ( ) He/Xe mixture [42] (reprinted with permission from the American Chemical Society)... 

Catalase was immobilized with gelatin by means of glutaraldehyde and fixed on a pretreated Teflon membrane served as enzyme electrode to determine hydrogen peroxide [248], The electrode response reached a maximum when 50mM phosphate buffer was used at pH 7.0 and at 35°C. Catalase enzyme electrode response depends linearly on hydrogen peroxide concentration between 1.0 X 10-5 and 3.0 X 10-3 M with response time 30 s. 

If the hydrogen peroxide concentration is large, the exchange reaction between R02 and H202 occurs rapidly, and this reaction becomes the rate-limiting stage of cyclic chain termination. 

Philippou, J.L., Johns, W.E. and Nguyen, T. (1982). Bonding wood by graft polymerisation. The effect of hydrogen peroxide concentration on the bonding and properties of particleboard. Holzforschung, 36(1), 37-42. 

FIGURE 4-43 Hydrogen peroxide concentrations at Riverside, California, in August 1970. Reprinted with permission from Bufalini et al. ... 

Effect of Hydrogen Peroxide. Hydrogen peroxide had two different effects on lignin peroxidase. Firstly it caused a lag time in the assay of activity. The length of the lag time before the onset of the reaction varied depending on the hydrogen peroxide concentration, pH and contact time. After the lag time the reaction star-... 

Gonzalez-Flecha, B. Demple, B. Homeostatic regulation of intracellular hydrogen peroxide concentration in aerobically growing Escherichia coli. J. Bacteriol. 1997, 179, 382-388. 

In cases like this, assay determination of hydrogen peroxide concentration would be the most sensitive metric. Titrametric determination will give a reliable measure of the specific ingredient that is most crucial to the polishing process. Assay by titration of low-concentration ingredients, such as hydrogen peroxide or ammonium hydroxide, both of which degrade over... 

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