Hydrocarbon chemistry degradation processes

Owing to the halogen substituents, HFC and HCFC atmospheric degradation leads to a number of products that do not occur in the oxidation of the unsubstituted hydrocarbons. It is important to understand the chemistry of these secondary species to assess the atmospheric impact of a particular HFC or HCFC. In some cases they continue to undergo gas-phase chemistry. Other species are resistant to gas-phase attack and are removed by photolysis or heterogeneous processes. 

Several historic publications that provided early evidence into the chemistry involved in this process were published between the 1920s and 1940s. Christiansen [4] and Backstrom [5] provided data in 1924 and 1927, respectively, that a chain reaction was involved. Next, in the early 1930s, Backstrom [6] and Ziegler and Ewald [7] demonstrated that the oxidation of hydrocarbons was initiated by free radicals. In 1942, Farmer and coworkers reported that an autocatalysis process involving free radicals and the formation of hydroperoxides was involved [8]. This 1942 paper identified the three steps responsible for the auto-oxidation of polyethylene that result in the degradation of polyethylene properties. These three steps were free-radical initiation, propagation and termination. 

All currently important industrial organic chemicals such as hydrocarbons, alcohols, polyols, ketones, acids, and phenol derivatives can be obtained by chemical processing of wood [106]. Plastics and synthetic fibres produced could be synthesized using the above chemicals from plant components. In order to develop both current and new polymers, eombining petrochemistry with wood chemistry has been considered. In this section, novel polymers synthesized using lignin degradation products are described [107, 108]. 

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