Hydrogen peroxide partial pressure

Isopropyl alcohol can be partially oxidized by a noncatalytic, liquid-phase process at low temperatures and pressure to produce hydrogen peroxide [7722-84-1] and acetone (24—26). 

The reaction with CoII(ACAC)2 was studied in more detail and the rate law was established. The reaction was found to be first-order with respect to the substrate and the catalyst concentrations, and the partial pressure of 02. The corresponding kinetic model postulates reversible formation of a H2DTBC-Con(ACAC)2 02 adduct which undergoes redox decomposition in the rate-determining step. Hydrogen peroxide is also a primary... 

Nitrous oxide is relatively soluble in water (2 x 10 2 M at atmospheric pressure), it reacts very rapidly with eaq( 7 x 109 M 1 s 1) and is practically inert toward OH and H (for the latter, k < 104 M 1 s 1). Because of partial scavenging of e q from the spurs G(OH) in N20-saturated solutions is 6-0. Hydrogen peroxide also converts ejq into OH very efficiently [reaction (6)], but it has... 

The vapour pressure and partial pressure of aqueous hydrogen peroxide are illustrated as a function of temperature in Figures 1.22 and 1.23 respectively. 

Figure 1.23 Partial pressure of hydrogen peroxide-water mixtures.

The experiments of Linnett and Tootal [44] were carried out at 565 °C and a pressure of 230 torr, just above the second limit, with a Pyrex vessel washed with nitric acid and distilled water. The products flowed out of the reaction vessel from the centre of the top via a straight tube of 2 mm diameter, and water and hydrogen peroxide were frozen out in two consecutive traps cooled in liquid air. The contents of the traps were analyzed later. The amounts of water and hydrogen peroxide, expressed as partial pressures in the gases leaving the reaction vessel, are shown in Figs. 8 and 9 as a function of the residence time. The results appear to fall into... 

Fig. 9. Variation of partial pressure of hydrogen peroxide formed with residence time for 2H2 + O2 at 230 torr and 565 °C (after Linnett and Tootal [44]). (By courtesy of The Combustion Institute.)...

The rate coefficients for the gas-phase reaction of OH radicals with dimethyl sulphide were determined using a relative rate method. The kinetic experiments were performed at a total pressure of 1000 mbar diluent gas (N2, synthetic air, or N2/O2 mixtmes), at three different O2 partial pressure ( 0 mbar, 205 mbar, and 500 mbar) and six different temperatures (250 K, 260 K, 270 K, 280 K, 290 K, and 299 K). The photolysis of hydrogen peroxide (H2O2) was used as the OH radical source ... 

Palladium and palladium-silver alloy membranes on porous alumina tubes were prepared by means of simultaneous and sequential electroless plating techniques [234], The membrane reactor was used for the direct formation of hydrogen peroxide by catalytic reaction of H2 and 02 at 293 K. The concentration of H202 increased with increases in the transmembrane partial pressure gradient of H2. A high concentration of H202 was obtained with a membrane that consisted of a palladium layer on the outer surface, porous alumina in the middle, and a palladium-silver alloy layer on the inside. 

Direct measurements have not been made, to my knowledge, regarding the lower limit of partial pressure of H2O in air necessary for formation of hydrogen peroxide. One can reason, however, that the limiting partial pressure ought to be the same as that necessary for a metal to corrode. Based on corrosion information, the critical lower limit for the partial pressure is more properly expressed in terms of relative humidity rather than absolute pressure. The critical relative humidity for corrosion is that which allows moisture to condense on the surface of a metal. This value, in turn, depends on the nature and concentration of hygroscopic impurities present both in the atmosphere and on the metal surface. For commercial steels in ordinary urban air, the critical relative humidity is about 50%, but for high purity metals in filtered air, the critical value is undoubtedly much lower. 

Naphthoquinone (198 mg, 1,25 mmol) was added and the mixture was poured into an autoclave containing a glass liner. The reactor was then pressured to 60 bar partial pressure of air and 10 bar partial pressure of CO in order to form a non-flammable gas mixture and the reaction was carried out for 1 hour at 70°C. At the end of the reaction, the hydrogen peroxide concentration was evaluated by titration with potassium permanganate. 

Also of consideration when comparing technologies is the possibility that, in the future, environmental authorities may specify that the best available practice must be adopted rather than defining specific numerical limits. In that case, sodium hydroxide scrubbing would lose out to its hydrogen peroxide competitor because sulfites in the recirculating solution would always allow some SO2 to escape because of the higher SO2 partial pressure in the gas stream. 

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