Degradative chlorination

Ozonation can be enhanced by the addition of ultraviolet (uv) radiation. This combination can be effective in degrading chlorinated organic compounds and pesticides. In addition, metal ions such as iron, nickel, chromium, and titanium [7440-32-6] can act as catalysts, as can ultrasonic mixing. 

Nitration with concentrated nitric acid degrades chlorins which are sensitive to oxidation. Here nitronium tetrafluoroborate in sulfolane is the reagent of choice. Both mononitrooc-... 

Shimizu et al. 2002). It was therefore shown that it is possible to produce transgenic plants with the capability of degrading chlorinated aromatic compounds, which are degraded with the formation of 3-chlorocatechol. 

Aerobic degradation has been shown to be most effective in reducing the concentration of aliphatic and aromatic hydrocarbon fuel compounds. Anaerobic reactions are more effective in degrading chlorinated hydrocarbons and long-chain animal fats and oils. Detailed study is necessary to determine the most-effective procedure for a specific site. 

Further investigation is needed to determine the fate of contaminants accumulated during phytoremediation. Evidence has shown that poplar trees degrade chlorinated solvents, such as trichloroethylene (TCE), through naturally occurring metabolic processes. The by-products, possibly carbon dioxide and chloride salts, may be stored in the tissues of the trees. It is not yet certain, however, the fate of many chemicals and metals. Contaminants that collect in the leaves may be released when the leaves drop, or may be eaten by animals and consequently bioaccumulated through the food chain. 

Plastics and elastomers Degrades chlorinated polyethylene, neoprene, nitrile rubber, polysulfide, polyurethane... 

Fava et al. developed a bioreactor to degrade chlorinated hydrocarbons in waste-water. Among other materials, polyurethane cubes were used as scaffolds. The degrading cells were immobilized in a fixed-bed reactor and showed significant... 

Sodium permanganate was used in place of the potassium salt in an experiment to degrade chlorinated materials in oils. Addition of methanol caused a violent reaction, spraying the mix about. The concentration, or acidity, of the material is not stated. However sodium permanganate is far more soluble in water, and presumably methanol, than is the potassium salt. Intimate mixing means more violent reaction. 

Evolution of Microbial Abilities to Degrade Chlorinated 5-Triazines 305... 

There is a general consensus (vide supra) on the environmental importance of catalytic reactions on the surface of many minerals. However, there is limited information in the literature about specific examples [9]. Systematic studies would allow the understanding of the dependence of the catalytic activity on mineral structure, mineral chemistry and surface reactivity. At the same time, this knowledge would be useful in designing remediation techniques based on minerals instead of synthetic catalysts. For example, sphalerite and ilmenite have been shown to be capable of degrading chlorinated carbon compounds via a photo catalytic mechanism [63]. 

In addition, the presence additional chlorinated compounds in the PET mixed plastics such as 3P/PVC/PET and MWP were found to be chlorine derivatives of benzoic acids. Kulesza and German [36] reported the influence of poly(vinyl chloride) on poly(ethylene terephthalate) pyrolysis. They reported that the chloroesters of terephthalic and benzoic acids were found with PVC and PET mixtures (1 1). In our present investigation, the PVC/PET ratio was 1 1 and contains the other plastics such as PE, PP and PS. The ratio of mixed plastics PP PE PS PVC PET was 3 3 3 1 1 and this composition was prepared are similar to the real municipal waste from Sapporo, Japan. 2-Methyl benzoylchloride was identified as one of the additional chlorinated hydrocarbons observed in 3P/PVC/PET and MWP degradation than 3P/PVC degradation chlorinated hydrocarbons. The other chlorinated hydrocarbons could not be identified in 3P/PVC/PET and MWP degradation. It is evident from the studies that the new chlorine compounds obtained due to the presence of PET in plastic samples in either model mixed on MWP. 

Recent work indicates that metallic iron emplaced in a permeable barrier or wall can degrade chlorinated solvents in groundwater by a coupled redox reaction in which the solvent is the oxidant and the reduciant is Fe metal or product Fe or H2 (cf. Wilson 1995 Roush 1995). A similar Fe metal barrier has been used to reduce chromate concentrations to values below detection, and has been suggested as a means of cleaning up groundwaters high in nitrate (Wilson 1995). 

Degradative chlorination. a-Sulfon n the presence of NaOMe (in methanol 1 Chlorination of A-tosyl-Af-alkylhydrazines he formation of chloroalkanes. ... 

Recent irradiation studies with blends of PVC and modifiers such as flexible polymers (EVA [205] or ENR -epox-idized natural rubber [206]) or PFMs (polyfunctional monomers) have shown that the irradiation achieves more crosslinking and less degradation (chlorine loss) at lower doses. Seven PFMs, used at 10 parts per hundred rubber (phr), were compared for effectiveness for increasing softening temperature, gel yield and swelling ratio in PVC wire formulations [207]. 

These reactions do not involve excitation of the aryl halide but are mentioned here because of interest in degrading chlorinated pollutants. Wastewater treatment involving hydroxyl radical production by photolysis of hydrogen peroxide or ozone is a well-known commercial process. Fe +, HjO, and UV have been used in combination (the photo-Fenton reaction) to enhance the degradation of Aroclor 1242, a mixture of PCBs. The conventional Fenton reaction produces hydroxyl radicals from and Fe + ... 

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