Chloroethenes

Vinyl chloride (also known as chloroethylene or chloroethene) is a colorless gas at normal temperature and pressure, but is typically handled as the hquid (bp —13.4° C). However, no human contact with the Hquid is permissible. Vinyl chloride is an OSHA-regulated material. 

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). 

Solvent Evaporation from Solutions of Thermoplastic Polymers. A solution of a copolymer of vinyl chloride (chloroethene) [75-01-4] C2H2CI, vinyl acetate (acetic acid ethenyl ester) [108-05-4] and a hydroxy-functional vinyl monomer having a number average molecular... 

CHLOROETHENE 80 C2H60 METHYL-ETHER -185.257 2.3378E-01 2.7075E-05 -112.93... 

Polyvinyl chloride Poly(chloroethene) Poly( 1 -chloroethylene)... 

Vinyl chloride -78 (Chloroethene) CH2 CHCI 472 4.0-22.0 1.0 2.1 -14 Colourless, sweet smelling liquefiable gas Polymerizes with light, heat, air or catalysts Normally inhibited Human carcinogen... 

Chemical Designations - Synonyms Chloroethene, Chloroethylene, Vinyl C Monomer, VCL,VCM Chemical Formula CH2=CHC1. 

B R22/152a/124 (61/11/28) 1140 1-chloroethene (vinyl chloride) CHC1=CH2... 

The alkoxyazocines in Table 1 are in tautomeric equilibrium with their bicyclic or propellanc forms, the equilibrium normally being shifted to the azocine side with the exception of the pentanoazocine 7. In this case, the compound exists as the propellane 6 below 100°C (in tetra-chloroethene), as revealed by NMR spectroscopy, and the azocine form predominates only above 150C. 

Polyvinyl Chloride. (Chloroethene homopolymer, Chloroethylene polymer, PVC, Vybak, Geon, Breon, Welvic, Deckor, Vinacort, Ultron, Vinyl-ite, Koroseal, Marvinol). A synthetic thermoplastic polymer white powder or colorl granules ... 

Poly(vinyl chloride) is the widely accepted trivial name for poly(l-chloroethene) and, in terms of worldwide production, is one of the three most important polymers in current use, the other two being poly(ethylene) and poly (styrene). PVC has numerous uses, including cable insulation, packaging, and toys. 

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). 

The microbial degradation of contaminants under anaerobic conditions using humic acids as electron acceptors has been demonstrated. These included the oxidations (a) chloroethene and 1,2-dichloroethene to CO2 that was confirmed using C-labeled substrates (Bradley et al. 1998) and (b) toluene to CO2 with AQDS or humic acid as electron acceptors (Cervantes et al. 2001). The transformation of l,3,5-trinitro-l,3,5-triazine was accomplished using Geobacter metallireducens and humic material with AQDS as electron shuttle (Kwon and Finneran 2006). 

Although these issues have already been briefly noted, they deserve a few additional comments. For freely water-soluble substrates that have low volatility, there are few difficulties in carrying out the appropriate experiments described above. There is, however, increasing interest in xenobiotics such as polycyclic aromatic hydrocarbons (PAHs) and highly chlorinated compounds including, for example, PCBs, which have only low water solubility. In addition, attention has been focused on volatile chlorinated aliphatic compounds such as the chloroethenes, dichloromethane, and carbon tetrachloride. All of these substrates present experimental difficulties of greater or lesser severity. 

Combined use of and NMR in a powerful combination to deduce the pathways of degradation of chloroethene (vinyl chloride) (Castro et al. 1992a,b)... 

The aerobic degradation of chloroethene (vinyl chloride) by Mycobacterium aurum strain LI proceeded by initial formation of an epoxide mediated by an alkene monooxygenase (Hartmans and de Bout 1992). This reaction has also been demonstrated to occur with Methylosinus trichosporium, even though subsequent reactions were purely chemical (Castro et al. 1992b). 

Both aerobic and reductive pathways were suggested for the degradation of 1,1,2-trichlo-roethane (Castro and Belser 1990)—a dominant aerobic pathway to chloroacetate and glyoxylate, and simultaneously a minor reductive reaction, which must also involve an elimination reaction with the formation of chloroethene (Figure 7.66). 

Considerable effort has been devoted to the anaerobic transformation of polychlorinated Cj alkanes and C2 alkenes in view of their extensive use as industrial solvents and their identification as widely distributed groundwater contaminants. Early experiments, which showed that tetrachloroethene was transformed into chloroethene (Vogel and McCarty 1985) (Figure 7.67), aroused concern though it has now been shown that complete dechlorination can be accomplished by some organisms. 

There has been snbstantial interest in the complete dechlorination of chloroethene to ethene, since chloroethene is an nndesirable prodnct of partial dechlorination of polychlorinated ethenes. Strains of Dehalococcoides sp., and especially D. ethenogenes that is possibly unique in being able to carry out the dechlorination of tetrachloroethene to chloroethene and ethene (Magnuson et al. 2000 Maymd-Gatell et al. 1999), have attracted particnlar attention ... 

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