Organic compounds halogenated

Nucleophilic substitution is one of a variety of mechanisms by which living systems detoxify halogenated organic compounds introduced into the environment Enzymes that catalyze these reactions are known as haloalkane dehalogenases The hydrolysis of 1 2 dichloroethane to 2 chloroethanol for example is a biological nude ophilic substitution catalyzed by a dehalogenase... 

Constituents. Complex halogenated organic compounds have been widely used in commerce in the last fifty years. A few representative examples are shown in Eigure 9 pentachlorophenol has been widely used as a wood preservative, and also for termite control. 

Flame retardants designated for nylon include halogenated organic compounds, phosphorous derivatives, and melamine cyanurate (160—163). Generally, flame retardants are difficult to spin in nylon because of the high loading required for effectiveness and their adverse effects on melt viscosity and fiber physical properties. 

Strong oxidizers and strong acids are incompatible with nikanolamines. Reactions, generating temperature and/or pressure increases, may occur with halogenated organic compounds. Alkan olamines are corrosive to copper and brass and may react. Contact with aluminum by alkan olamines, particularly when wet or at elevated temperatures (60°C), should be avoided. 

The toxicity of chlorine residuals to aquatic life has been well documented. Studies indicate that at chlorine concentrations in excess of 0.01 mg/1, serious hazard to marine and estuarine life exists. This has led to the dechlorination of wastewaters before they are discharged into surface water bodies. In addition to being toxic to aquatic life, residuals of chlorine can produce halogenated organic compounds that are potentially toxic to man. Trihalomelhanes (chloroform and bromoform), which are carcinogens, are produced by chlorination. 

Kirk, K L, Biochemistry of the Halogens, Vol II Biochemistry of Halogenated Organic Compounds Plenum New York, 1991 Peters, R A, Wakelm, R W, Buffa, P, Thomas, L C Proc Roy Soc (London), B1953,140, 497... 

G.G. Choudhry, O. Hutzinger, Mechanistic Aspects of Thermal Formation of Halogenated Organic Compounds Including Polychlorinated Dibenzo-p-dioxins, Gordon Breach Publ. New York (1983). 

Pfaffenberger CD, Peoples AJ, Enos HF. 1980. Distribution of volatile halogenated organic compounds between rat blood serum and adipose tissue. Int J Environ Anal Chem 8 55-65. 

Morgan P, RJ Watkinson (1989b) Microbiological methods for the cleanup of soil and ground water contaminated with halogenated organic compounds. FEMS Microbiol Revs 63 277-300. 

Heterogeneous solid catalysts can enhance the performance. Chlorination has the disadvantage that small quantities of undesirable halogenated organic compounds can be formed. 

Teo KC, Xu Y, Yang C (2001) Sonochemical degradation of toxic halogenated organic compounds. Ultrason Sonochem 8 241-246... 

Metal salt of aromatic sulfonamide (+ metal salt of perfluorometal-ate + halogenated organic compounds) Total 0.01-1.0 26-39... 

Leiker, T.J., C.E. Rostad, C.R. Bames, and W.E. Pereira. 1991. A reconnaissance study of halogenated organic compounds in catfish from the lower Mississippi River and its major tributaries. Chemosphere 23 817-829. Littrell, E.E. 1986. Shell thickness and organochlorine pesticides in osprey eggs from Eagle Lake, California. Calif. Fish Game 72 182-185. 

Mazur DJ, Weinberg NL (1987) Methods for the electrochemical reduction of halogenated organic compounds, US, US 4,702,804 Chem Abstr 108 (1988) 175949s... 

Highly halogenated organic compounds such as polychlorinated biphenyls and perchloroethylene appear to be too highly oxidised and low in energy content to serve as sources of electrons and energy for microbial metabolism. Bacteria are more likely to use them as electron acceptors in cell-membrane-based respiration processes [154]. The environmental fate of halogenated polymers such as polyvinylchloride or Teflon may depend on the question of whether it will be appropriate to sustain de-halorespiration processes. 

Halogenated ketones, 10 598 Halogenated organic compounds, bioremediation, 3 772-776... 

Common surfactants such as Tween, Triton,5 and sodium dihexyl sulfosuc-cinate, among many others, have been used to extract organic compounds from soil. In the field, they have been particularly useful in the remediation of soils contaminated with halogenated organic compounds, oils, and other hydrocarbon compounds [24],... 

Removal of soluble toxic halogenated organic compounds... 

Gron [23] has reviewed methods for the determination of halogenated organic compounds (adsorbable, volatile and extractable), with particular reference to their applicability to wastewaters and marine samples (marine sediments and marine organisms). Typical analytical results for marine... 

Laturnus F (1995) Release of volatile halogenated organic-compounds by unialgal cultures of polar macroalgae. Chemosphere 31 3387-3395... 

Laturnus F, Wiencke C, Kloser H (1996) Antarctic macroalgae - sources of volatile halogenated organic compounds. Mar Environ Res 41 169-181 Lebar ML, Heimbegner JL, Baker BJ (2007) Cold-water marine natural products. Nat Prod Rep 24 774-797... 

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