Polychlorinated ethane

Schanke CA, LP Wackett (1992) Environmental reductive elimination reactions of polychlorinated ethanes mimicked by transition-metal coenzymes. Environ Sci Technol 26 830-833. 

Town C, Leibman KC. 1984. The in vitro dechlorination of some polychlorinated ethanes. Drug Metab Disp 12 4-8. 

Assume that the three polychlorinated ethanes, 1,1,2,2-tetrachloroethane, 1,1,1,2-tetrachloroethane, and pentachloroethane are introduced into a lake by an accident. Calculate the half-life for chemical transformation of each of the three compounds in (a) the epilimnion of the lake (T= 25°C, pH 8.5) and (b) the hypolimnion of the lake (7 = 5°C, pH 7.5). Furthermore, indicate for each compound the pH (for the epilimnion and for the hypolimnion) at which the neutral and the base-catalyzed reaction would be equally important. What is(are) the transformation produces) of these compounds Explain the different reactivities of the three compounds. You can find all necessary data in Table 13.7. 

Allyl chloride or polychlorinated ethanes with a cleavable C-Cl bond were also investigated thermally (250-290 °C) by Haszeldine et al. [267]. Beside normal and reverse monoadducts produced in poor yields, cyclic or thermal rearranged compounds were obtained. 

Arnold WA, Ball WP, Roberts AL. Polychlorinated ethane reaction with zerovalent zinc pathways and rate control. J Contam Hydrol 1999 40 183-200. 

To gain insight into the structural features of halogenated aliphatics that affect the relative rates of the neutral and base-catalyzed hydrolysis pathways, Jeffers et al. (1989) measured k and kb for a series of polychlorinated ethanes, propanes and... 

Mabey WR, Barich V, Mill T. Hydrolysis of polychlorinated ethanes. Extended Abstracts, 186th National Meeting of the American Chemical Society, Washington, D.C., 1980. 

There are several PHA extraction methods found in the literature (Figure 6.1). Solvent extraction is the oldest and most commonly used method to extract PHA from the lyophilised biomass and has been used since the discovery of PHA by Lemoigne [9]. Typically, halogenated solvents, such as chloroform, dichloromethane and polychlorinated ethane, are used in the extraction of PHA [10,11]. These solvents act by weakening the cell membrane and subsequently dissolve the PHA. On a laboratory scale, the PHA-containing... 

Until the 1970s the chemical used as the impregnating and dielectric medium for capacitor units was PCB (polychlorinated biphenyl) liquid. It was found to be toxic and unsafe for humans as well as contamination of the environment. For this reason, it is no longer used. The latest trend is to use a non-PCB, non-toxic, phenyl xylyl ethane (PXE-oil), which is a synthetic dielectric liquid of extremely low loss for insulation and impregnation of the capacitor elements or to use mixed polypropylene or allpolypropylene (PP) liquids as the dielectric. A non-oil dielectric, such as epoxy resin, is also used. 

Neostar A process for destroying waste organic chlorides (e.g., polychlorinated biphenyls) by heating with steam and hydrogen at over 1,000°C. The products are methane, ethane, other chlorine-free hydrocarbons, and hydrochloric acid. Developed by Cerchar, France. 

DDD Dichloro(chlorophenyl)-bis Ethane DDE Dichlorodiphenyldichloroethylene Dichlorobenzene, 1,2 Dichlorobenzene, 1,3 Dichlorobenzene, 1,4 Hexachlorobenzene Polychlorinated Benzenes Polychlorinated Biphenyls PCBs Aroclor Ring-Substituted Aromatics Tetrachlorobenzene Trichlorobenzene, 1,2,4 Saturated Alkyl Halides Bromodichloromethane Bromoform Tribromomethane Butyl Chloride Chlorobutane Carbon Tetrachloride Carbon Tetrafluoride Chloroform Trichloromethane Chloromethane Methyl Chloride Dibromochloromethane Dibromoethane, 1,2 Ethylene Dibromide Dibromomethane... 

Permeation of Protective Garment Materials by Liquid Halogenated Ethanes and a Polychlorinated Biphenyl... 

Chlorinated ethanes are chemical compounds of the general structure C2HxCl x(X 5) and are widely used in the industrial world as solvents, chemical intermediates, cleaning fluids, fumigants, and for numerous other purposes including uses in petroleum-refining. Likewise,.the chemicals in the class of compounds known as polychlorinated biphenyls Cl (2< < 10) (PCBs) have... 

As a result, free-radical chlorination of alkanes is a nonselective process. Except when only one type of replaceable hydrogen is present (methane, ethane, neopentane, unsubstituted cycloalkanes), all possible monochlorinated isomers are usually formed. Although alkyl chlorides are somewhat less reactive than alkanes, di- and polychlorinations always occur. The presence of a chlorine atom on a carbon atom tends to hinder further substitution at that carbon. The one exception is ethane that yields more 1,1-dichloroethane than 1,2-dichloroethane. The reason for this is that chlorination of an alkyl chloride occurs extremely slowly on the carbon atom adjacent to the one bearing the chlorine atom (vicinal effect).115... 

Direct oxidation of the lesser chlorinated ethenes, ethanes, polychlorinated benzenes, and chlorobenzene has been reported. Wiedemeier et al. [25] summarize a number of studies that report direct aerobic oxidation of vinyl chloride (VC), 1,2-dichloroethane, the three dichlorobenzene isomers, 1,2,4-trichlorobenzene, and 1,2,4,5-tetrachlorobenzene. Bradley [33] reports that DCE has served as a primary substrate for energy production with oxygen as the electron acceptor, though use of DCE as a sole carbon source has not been demonstrated. Rittmann and McCarty [29] also report that the two least chlorinated methanes (dichloromethane and chloromethane) as well as chloroethane can be directly oxidized under aerobic conditions. Direct oxidation of the chlorinated compounds is typically modeled using either first-order or Monod kinetics [29,31]. 

Note Binary combinations at the 1188 sites surveyed. MeCl = methylene chloride, PCBs = polychlorinated biphenyls, Perc = perchloroethylene (tetrachloroethylene), 1,1,1-TCA = 1,1,1-trichloro-ethane, TCE = trichloroethylene, Trans-1,2-DCE = trans-l,2-dichloroethylene, 1,1-DCA = 1,1-dichloroethane, 1,1-DCE = 1,1-dichloroethene. 

See also Chlordane DDT (Dichlorodiphenyltrichloro-ethane) Dioxins Food and Drug Administration, US Mercury Methylmercury Polychlorinated Biphenyls (PCBs). 

The first considerations in determining the most appropriate SPE methodology are the structure and polarity of the analytes of interest. Table 7.1 shows a selection of environmentally important compounds as examples for SPE methods development from aqueous solution. The polarity range of environmentally important analytes is broad and stretches from nonpolar compounds, such as polychlorinated biphenyls (PCBs), dioxin, and l,l,l-trichloro-2-2-bis(4-chlorophenyl)ethane (DDT), to moderately nonpolar compounds, such as polynuclear aromatic hydrocarbons (PAHs), to polar compounds such as the herbicides. The most polar compounds are those containing multiple polar functional groups or an ionic functional group, either anionic or cationic. The type of SPE cartridge and elution solvent that are used depends on the polarity of the compound. 

Some important persistent environmental pollutants, such as l,l,l-trichloro-2,2-bis (4-chlorophenyl)ethane (DDT), polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and polybrominated diphenyl ethers (PBDEs), are aryl halides therefore, studies... 

Analytes CB, chlorobenzenes DDE, l,l-dichloro-2,3-bis(4-chlorophenyl)ethane DDT, l,l-dichloro-2,3-bis(4-chlorophenyl)ethylene DBF, decabromobiphenyls HBCD, Hexabromo-cyclododecane HpBB, heptabromobiphenyl PBB, polybrominated biphenyl PBCCH, pentabromochlorocyclohexane PBDE, polybrominated diphenyl ether PBT, Polybutylene terephthalate PCB, Polychlorinated biphenyl PBDD, polybrominated dibenzo-/ -dioxins PBDF, polybrominated dibenzofuranes PCN, polychlorinated naphthalenes PCP, polychlorinated phenols PBB, polybrominated biphenyl PeBDE, pentabromodiphenyl ether PET, Polyethylene terephthalate PXDDs, polyhalogenated dibenzo-p-dioxins PXDFs, polyhalogenated dibenzofurans TBBPA, tetrabromobisphenol A TBPA, tetrabromophthalic anhydride TCBPA, tetrachlorobisphenol A TDBPP, tris(2,3-dibromopropyl)phosphate. 

Analytes DDE, l,l-dichloro-2,3-bis(4-chlorophenyl)ethane DDT, l,l-dichloro-2,3-bis(4-chlorophenyl)ethylene HCB, hexachlorinated benzenes PBB, polybrominated biphenyl OPE, organophosphorus esters PBDE, polybrominated diphenyl ether PCP, polychlorinated phenols. 

This field lists other names by which the chemical is known. Many of these names are trade names. The most commonly used synonyms are given. The following are examples of synonyms by which some chemicals are known calcium carbonate is also known as agricultural limestone 1,1,2-trichloroethane is also known as ethane trichloride or vinyl trichloride and polychlorinated biphenyls are referred to as Aroclors. An exhaustive treatment of synonyms is not possible in a short information sheet. 

Persistent or non-degradable environmental chemicals - even those with low volatility - may be dispersed around the globe. Polychlorinated biphenyls (PCB), polychlorinated dibenzodioxins and dibenzofurans (PCDD, PCDF), l,l,l-trichlor-2,2-bis(4-chlorphenyl)-ethan DDT, hexachlorocyclohexane (HCH) and hexachlorobenzene (HCB) have been found in samples from the Arctic and Antarctic and in the tissues of marine animals. Although the open use of many of these chemicals has been prohibited in most industrialized countries, considerable residues still remain in the environment. It is estimated that about 20% of the global production of PCBs (230 000 t/a) persists in the upper layers of the oceans and that a further 7901 are present in the atmosphere (Fiedler and Lau, 1998). Such contamination may accumulate in organisms and have negative effects that go as far as the death of whole populations in ecosystems (Jdrgensen, 1998). 

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