Hydrogen peroxide temperature effect

One of the most effective promoters of the oxidation of hydrocarbons, with a relatively clear mechanism of chemical action, is hydrogen peroxide. The initiation of the partial oxidation of methane with hydrogen peroxide, the effect of which consists in reducing either the temperature of the process or its induction period, was studied in [170]. Of the molecular compounds investigated in [171], H2O2 turned out to be the most effective in reducing the ignition delay time, twice as superior in this respect to methanol. 

TetrabromobisphenoIA. Tetrabromobisphenol A [79-94-7] (TBBPA) is the largest volume bromiaated flame retardant. TBBPA is prepared by bromination of bisphenol A under a variety of conditions. When the bromination is carried out ia methanol, methyl bromide [74-80-9] is produced as a coproduct (37). If hydrogen peroxide is used to oxidize the hydrogen bromide [10035-10-6] HBr, produced back to bromine, methyl bromide is not coproduced (38). TBBPA is used both as an additive and as a reactive flame retardant. It is used as an additive primarily ia ABS systems, la ABS, TBBPA is probably the largest volume flame retardant used, and because of its relatively low cost is the most cost-effective flame retardant. In ABS it provides high flow and good impact properties. These benefits come at the expense of distortion temperature under load (DTUL) (39). DTUL is a measure of the use temperature of a polymer. TBBPA is more uv stable than decabrom and uv stable ABS resias based oa TBBPA are produced commercially. 

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. 

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]. 

Most of the controlled corrosion studies on beryllium have been carried out in the USA in simulated reactor coolants. The latter have usually been water, aerated and de-aerated, containing small amounts of hydrogen peroxide and at temperatures up to 300-350°C. Many variables have been examined, covering surface condition, chemical composition, temperature, pH, galvanic effects and mechanical stress . 

Homolytic scission of the 0-0 bond of hydrogen peroxide may be effected by heat or UV irradiation.245 The thermal reaction requires relatively high temperatures (>90 Photolytic initiation generally employs 254 nm light. Reactions in organic media require a polar cosolvent (e.g. an alcohol). 

The low temperature ALD process for hafnium silicate films using HfCl2[N(SiMe3)2]2 and H2O was modified to improve the film properties by two different methods. With hydrogen peroxide, the silicon content in the film increased to Si/(Hf+Si)=0.2 at 2001 and the impurity levels decreased due to its strong oxidation effect. By introducing TBOS as an additional Si precursor, the silicon content in the film increased to Si/(Hf+Si)=0.5 at 200 °C and the hafiiium silicate films became fully oxidized with O/(Hf+Si)=2.0. 

Returning to the explanation of induced reactions, we can say the following. Friend s proposal , according to which the error in the H2O2 determination is caused by reaction (83) catalyzed by manganese(II) or cerium(III) formed in the primary reaction between hydrogen peroxide and permanganate or cerium(IV) cannot be accepted. The reaction between the ions mentioned and peroxydisulphate at room temperature is very slow, and, furthermore, the increase in acidity —in contrast to its effect on the induced reaction —promotes the oxidation. There is... 

Preparing tert-butyl peroxide by the effect of 50% hydrogen peroxide in the presence of 78% sulphuric acid has led to numerous accidents. They were due to the high exothermicity of the reaction causing a temperature rise and leading to the explosive decomposition of the peroxide formed, if the temperature rise is badly monitored. 

Increased usage of recycled fiber in combination with system closure and Hydrogen Peroxide (HP) bleaching at moderate temperatures, has developed microbe cultures that are very effective in decomposing (HP). As this problem often comes slowly when the mills are closing their water loops and reuses their wastewater it is sometimes difficult to say when it needs to be treated. 

Figure 10.28 Effect of temperature on the whiteness index of linen bleached using urea-activated hydrogen peroxide [243], Treated with 7 g/l hydrogen peroxide and 8 g/l urea for 150 min at pH 6 and 50 1 liquor ratio...

A survey, with many references, of 14 classes of preparative reactions involving hydrogen peroxide or its derivatives emphasises safety aspects of the various procedures [11]. Following the decomposition of 100 1 of 50% aqueous hydrogen peroxide which damaged the 630 1 stainless vessel rated at 6 bar, the effect of added contaminants and variations in temperature and pH on the adiabatic decomposition was studied in a 1 1 pressure vessel, where a final temperature of 310°C and a pressure around 200 bar were attained. Rust had little effect, but addition of a little ammonia (pH increased from 1.8 to 6.0) caused the induction period to fall dramatically, effectively from infinity to a few h at 40°C and a few min at 80°C. Addition of sodium hydroxide to pH 7.5 reduced the induction period at 24°C from infinity to about 4 min [12],... 

Abrahamsson K, Choo KS, Pedersen M, Johansson G, Snoeijs P (2003) Effects of temperature on the production of hydrogen peroxide and volatile halocarbons by brackish-water algae. Phytochemistry 64 725-734... 

There is as yet no known enzyme that breaks the C—F bond in fluoroacetic acid, FCH2COOH, or in related compounds. It is interesting to note, however, that in the course of our investigations2 on peroxidase-catalysed oxidations, we have effected an enzymic cleavage of the C—F bond in p-fluoroaniline.3 In acetate buffer (pH 4-5) and at room temperature, the amine was oxidized by hydrogen peroxide and peroxidase to give mainly the red crystalline 2-amino-5-p-fluoroanilinobenzoquinone di-p-fluoroanil (XX). 

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