Hydrogen peroxide, spontaneous decomposition

Because the electrolyte contains excess alkaH which could cause spontaneous decomposition of the hydrogen peroxide, the H2O2 in the product... 

A hydrogen peroxide still is used to concentrate peroxide by removing water. The still is of high-purity aluminum, a material that is noncatalytic to the decomposition of peroxide vapor. The still is designed to produce 78% hydrogen peroxide. It will explode spontaneously at about 90%. Illustrate some recommended design features for this still. 

An exactly similar reaction of phenylhydrazine will be discussed later (p. 296). A simple example of this type is provided by the spontaneous decomposition, of hydrogen peroxide into oxygen and water ... 

The spontaneous decomposition of hydrazobenzene, like that of hydrogen peroxide, is catalyticaUy accelerated by metallic platinum. 

Frimer, A. A., J. Org. Chem., 1977, 42, 3194-3196, footnote 7 A new method of preparation involves interaction of ally lie halides in solvents with 98% hydrogen peroxide in presence of silver ion and base at ambient temperature under argon. The reactions must be run in the dark to prevent precipitation of metallic silver, which will catalyse decomposition of the hydroperoxide or excess hydrogen peroxide. In an experiment not run in the dark, the hydroperoxide from 3-chlorocyclohexene ignited spontaneously after isolation and concentration. 

Chemical/Physical. Releases toxic nitrogen oxides when heated to decomposition (Sax and Lewis, 1987). Ignites spontaneously in air or in contact with hydrogen peroxide, nitric acid, or other oxidizers (Patnaik, 1992). 

The decomposition of hydrogen peroxide to gaseous O2 and water is a spontaneous process, yet H2O2 is stable for long periods of time. Explain. 

The shift in the redox potentials for O2 within aprotic solvents [-0.65 V in dimethylformamide (DMF) versus -0.16 V in H2O] is the result of a much weaker solvation of anions by such media relative to water (for O2 -, about 88 kcal mol in DMF versus 100 kcal mol l in H2O). Likewise, the addition of base to hydrogen peroxide results in its spontaneous decomposition. 

E Koubek, ML Haggett, CJ Battalgia, Ml-r Kairat, HY Pyun, and JO Edwards. Kinetics and mechanism of the spontaneous decomposition of some peroxoacids, hydrogen peroxide and t-butyl hydroperoxide. J. Am. Chem. Soc. 85 2263-2268, 1963. 

Radicalar polymerizations are very commonly used. In this case, the active site is an atom bearing a unpaired electron (free bond). The initiator is an organic material which can spontaneously split by homolytic breaking and in this way can produce radicals able to attack the monomer and thus to initiate the process. Actually, as initiators, one uses peroxides (R -O-O-R"), hydroperoxides (R -O-OH) (for instance hydrogen peroxide H202, or cumene hydroperoxide) and aliphatic azoics (R -N=R"). For each initiator, there is a domain of temperature often narrow (about 10 degrees) in which the homolytic decomposition occurs with an acceptable velocity. 

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