Chlorine energy decomposition

The solutions are most stable above pH 11 where the decomposition rate is nearly independent of pH. In this region, the decomposition rate has a second-order dependence on the concentration of hypochlorite. It also increases with increa sing ionic strength. Thus concentrated solutions decompose much faster than dilute solutions. Because of an unusually high activation energy, the decomposition rate increases greatiy with temperature. Nevertheless, solutions with less than about 6% available chlorine and a pH above 11 have acceptable long-term stabiUty below about 30°C. 

The heat of formation of SbCl5 is 105 kcal per equivalent it would therefore require 42 kcal per mol Cl2 to decompose the compound into antimony and chlorine. This reaction can occur only at high temperatures, i.e. above 1000°K, and thus, if only the decomposition reaction is considered, the compound can be said to be very stable. There is, however, another reaction that requires much less energy, viz. the decomposition into a compound of lower valency. The reaction... 

For addition of Cl atoms, the dissociation energy of the radicals AX has been estimated at about 20-22 kcal./mole. At room temperature k ifki(A) should be well below 10-3 and mechanism (C) should be obeyed and has indeed been frequently observed. At higher temperatures (about 225°C.) k 2/k2(A) 10-3 and a change to mechanism (B) should occur. This has been confirmed experimentally by Adam et al. (1) in a study of the photochlorination of tetrachlorethylene. They observed a maximum in the rate and a change in mechanism at about 180°C., as a result of the increased importance of the radical decomposition reaction (—2). From their data they were able to deduce the Arrhenius parameters for this reaction. In extensions of this work Goldfinger and his collaborators have carried out competitive experiments with a number of hydrocarbons and chlorinated hydrocarbons. 

The interaction of fluorine with an organic compound liberates a quantity of energy which is frequently of the order of magnitude of, or greater than, the energy which binds the carbon atoms in chains. It is estimated 63 that the addition of fluorine to a double bond liberates ldS calories per mole, whereas chlorine liberates only 30 calories. Careful control qf the temperature throughout the reacting masses is therefore essential. Even in the most favorable cases, much decomposition occurs and carbon tetrafluoride is frequently the main reaction product.62-6 ... 

Naterer, G.F., et al. (2008), Thermochemical Hydrogen Production with a Copper-chlorine Cycle, I Oxygen Release from Copper Oxychloride Decomposition , International Journal of Hydrogen Energy, 33, 5439-5450. 

The decompositions of bromobenzene [717] and chlorobenzene ions [716] have been studied by the special PIPECO experiment using variable source residence times. In the case of chlorobenzene, increasing the residence time from 0.7 to 8.9 ps resulted in a shift (kinetic shift) in the breakdown curves by 0.4 eV. Detailed analysis of the effects of varying residence time provided information on the k(E) vs. E curve in the vicinity of 104—106 s-1. The k(E) vs. E curve obtained differed significantly [by almost an order of magnitude in k(E) at some energies] from the curve reported in the earlier PIPECO study of metastable ions [22], The initial analysis [716] placed the critical energy for chlorine loss at 3.40 0.05 eV, but this has subsequently been revised to 3.19 0.02 eV [717]. The transition state was found to be loose . 

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