Addition of carbon atoms to double and triple bonds

11 ADDITION OF CARBON ATOMS TO DOUBLE AND TRIPLE BONDS 

Despite the fact that hydroxyl radicals are of critical importance in the chemistry of many combustion processes, and are involved in photochemical processes in the atmosphere, there has only been a very slow development of reliable kinetics for the reactions of tiiis radical species. The problem lies very largely in the difficulty of preparing and measuring the concentration of the OH radical. In most instances, the older literature records chemistry which does not actually involve hydroxyl radicals at all, or only as a relatively unimportant species among other reactive radicals. This brief summary will not be exhaustive, but will cite the more reliable studies. The review by Wilson [6] has been of major assistance. 

The decomposition of hydrogen peroxide is also a source of hydroxyl radicals, but the reaction of OH with H2 O2 to give HO2 

Finally, the photolysis of water vapour is also a source of hydroxyl radicals, and may well be considered a good one if recombination of OH to form hydrogen peroxide is kept to a minimum. Here, too, formation of hydrogen atoms must be taken into account. 

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