1,1,2-Trichloroethene

I. I-dichli)rt)ethene, I. l-dichloroethylene, asymmetric dichloroethene, CH2=CCl2, colourless liquid, b.p. 37 C. Prepared by heating 1,1,1- or 1,1,2-trichloroethene with excess lime at 70-80 C. Polymerizes readily to an insoluble solid. 

HCCI2CHCI2. Colourless toxic liquid with a chloroform-like odour, b.p. 146 C. Manufactured by passing chlorine and ethyne separately into a solution of SbClj in tetra-chloroethane. Reacts with dilute alkalis to give trichloroethene . 

Minor amounts of acetylene are used to produce chlorinated ethylenes. Trichloroethylene (trichloroethene) and perchloroethylene (tetrachloroethene) are prepared by successive chlorinations and dehydrochlorinations (see Chlorocarsons and chlorohydrocarsons). The chlorinations take place in the Hquid phase using uv radiation and the dehydrochlorinations use calcium hydroxide in an aqueous medium at 70—100°C. Dehydrochlorination can also be carried out thermally (330—700°C) or catalyticaHy (300—500°C). 

Chlorination of various hydrocarbon feedstocks produces many usehil chlorinated solvents, intermediates, and chemical products. The chlorinated derivatives provide a primary method of upgrading the value of industrial chlorine. The principal chlorinated hydrocarbons produced industrially include chloromethane (methyl chloride), dichloromethane (methylene chloride), trichloromethane (chloroform), tetrachloromethane (carbon tetrachloride), chloroethene (vinyl chloride monomer, VCM), 1,1-dichloroethene (vinylidene chloride), 1,1,2-trichloroethene (trichloroethylene), 1,1,2,2-tetrachloroethene (perchloroethylene), mono- and dichloroben2enes, 1,1,1-trichloroethane (methyl chloroform), 1,1,2-trichloroethane, and 1,2-dichloroethane (ethylene dichloride [540-59-0], EDC). 

Trichloroethylene [79-01-6J, trichloroethene, CHCL=CCL2, commonly called "tri," is a colorless, sweet smelling (chloroformlike odor), volatile Hquid and a powerhil solvent for a large number of natural and synthetic substances. It is nonflammable under conditions of recommended use. In the absence of stabilizers, it is slowly decomposed (autoxidized) by air. The oxidation products are acidic and corrosive. Stabilizers are added to all commercial grades. Trichloroethylene is moderately toxic and has narcotic properties. 

Zeotropic Blends (% by mass) 1120 trichloroethene CHCl=CCl2... 

Interestingly, it appears that earlier selective pressure by dichlorodiphenyl trichloroethene (DDT) raised the frequency of kdr genes in the population before pyrethroids came to be used. Thus, some pyrethroid resistance already existed before these insecticides were applied in the field. 

Acetylene trichloride 1-chloro-2,2-dichloroethylene 1,1 -dichloro-2-chloroethylene ethylene trichloride trichlororide TCE 1,1,2-trichloroethylene trichloroethene... 

Barrio-Lage G, Parsons FZ, Nassar RS. 1987. Kinetics of the depletion of trichloroethene. Environmental Science and Technology 21 366-370. 

Bimer G, Vamvakas S, Dekant W, et al. 1993. Nephrotoxic and genotoxic N-acetyl-S-dichlorovinyl-L-cysteine is a urinary metabolite after occupational 1,1,2-trichloroethene exposure in humans Implications for the risk of trichloroethene exposure. Environ Health Perspect 99 281-284. 

Dekant W, Koob M, Henschler D. 1990. Metabolism of trichloroethene—vivo and in vitro evidence for activation by glutathione conjugation. Chem Biol Interact 73 89-101. 

Ewers J, Freier-Schroder D, Knackmuss H-J. 1990. Selection of trichloroethene (TCE) degrading bacteria that resist inactivation by TCE. Arch Microbial 154 410-413. 

Eyre RJ, Stevens DK, Parker JC, et al. 1995a. Acid-labile adducts to protein can be used as indicators of the cysteine conjugate pathway of trichloroethene metabolism. J Toxicol Environ Health 46 443-464. 

Henschler D, Vamvakas S, Lammert M, et al. 1995. Increased incidence of renal cell tumors in a cohort of cardboard workers exposed to trichloroethene. Arch Toxicol 69 291-299. 

Khan FM, Kaphalia BS, Prabhakar BS, et al. 1995. Trichloroethene-induced autoimmune response in female MRL +/+ mice. Toxicol Appl Pharmacol 134 155-160. 

Parsons F, Wood PR, Demarco J. 1984. Transformations of tetrachloroethene and trichloroethene in microcosms and groundwater. J Am Water Works Assoc 76 56-59. 

Ruijten MW, Verberk MM, Salle HJ. 1991. Nerve function in workers with long term exposure to trichloroethene. Br J Ind Med 48 87-92. 

For trichloroethene (TCE), the stoichiometric amount of iron and the effect of different preparations determine the outcome of the several competing reactions. Coupling products such as butenes, acetylene and its reduction products ethene and ethane, and products with five or six carbon atoms were formed (Liu et al. 2005). Although a held-scale application successfully lowered the concentration of TCE, there was evidence for the formation of the undesirable di-l,2-dichloroethene and 1-chloroethene (vinyl chloride) in the groundwater (Quinn et al. 2005). 

Experiments have been carried out to compare nanoscale catalysts composed of Fe-, Ni-, and Co-complexes of several porphyrins or cyanocobalamin (Dror et al. 2005). A cobalt-porphyrin complex and cyanocobalamin in the presence of Ti(III)citrate reduced the initial concentrations of tetrachloromethane and tetrachloroethene by —99.5%, and the porphyrin was equally effective with trichloroethene. The advantage of using heterogeneous catalysts was shown by experiments in repetitive cycling of tetrachloromethane. Zero-valent metals degrade vicinal dichlorides such as tetrachloroethene by a-elimination to produce dichloroacetylene and hnally acetylene (Roberts et al. 1996). 

Using a polymer electrolyte membrane cell in which flowed through the anode chamber. The major intermediate chlorinated products from tetrachloroethene or tet-rachloromethane were trichloroethene or trichloromethane, and these were finally reduced to a mixture of ethane and ethene, or methane (Liu et al. 2001). 

Reduction of trichloroethene to ethane took place in a modified fuel cell to which was introduced, although the loss of catalytic activity with time could present a serious limitation (Ju et al. 2006). 

Glod G, W Angst, C Holliger and RP Schwartzenbach (1997) Corrinoid-mediated reduction of tetrachloro-ethene, trichloroethene, and trichlorofluoroethene in homogeneous solution reaction kinetics and reaction mechanisms. Environ Sci Technol 31 253-260. 

Kubatova A, AJM Lagadec, SB Hawthorne (2002) Dechlorination of lindane, dieldrin, tetrachloroethane, trichloroethene and PVC in subcritical water. Environ Sci Technol 36 1337-1343. 

A strain of Rhodococcus sp. was capable of degrading a number of chlorinated aliphatic hydrocarbons including vinyl chloride and trichloroethene, as well as the aromatic hydrocarbons benzene, naphthalene, and biphenyl (Malachowsky et al. 1994). 

The oxidation of a number of chloroalkanes and chloroalkenes including dichlorometh-ane, chloroform, 1,1,2-trichloroethane, and 1,2,2-trichloroethene (Vannelli et al. 1990). Although the rate of cometabolism of trihalomethanes increased with levels of bromine substitution so also did toxicity. Both factors must therefore be evaluated in the possible application of this strain (Wahman et al. 2005). 

The last example is mediated by a monooxygenase that can be induced by benzene, toluene, and ethylbenzene, and also by xylenes and styrene. A plausibly analogous situation exists for strains of Pseudomonas sp. and Rhodococcus erythropolis that were obtained by enrichment with isopropylbenzene, and that could be shown to oxidize trichloroethene (Dabrock et al. 1992). In addition, one of the pseudomonads could oxidize 1,1-dichloroeth-ene, vinyl chloride, trichloroethane, and 1,2-dichloroethane. 

The induction of the monooxygenases for the degradation of trichloroethene by aromatic substrates and vice versa is discussed in Chapter 8, Part 1. 

The degradation of trichloroethene by methylotrophic bacteria involves the epoxide as intermediate (Little et al. 1988). Further transformation of this may produce CO that can toxify the bacterium, both by competition for reductant and by enzyme inhibition (Henry and Grbic-Galic 1991). The inhibitory effect of CO may, however, be effectively overcome by adding a reductant such as formate. 

The degradation of trichloroethene by Alcaligenes eutrophus JMP134 is carried out by either a chromosomal phenol-dependent pathway, or by the plasmid-borne 2,4-dichloro-phenoxyacetate pathway (Harker and Kim 1990). 

Dabrock B, J Riedel, J Bertram, G Gottschalk (1992) Isopropylbenzene (cumene)—a new substrate for the isolation of trichloroethene-degrading bacteria. Arch Microbiol 158 9-13. 

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