Trichloroethylene, fluorination

A number of inhalation anesthetics have been introduced to clinical practice, some of which are Hsted in Table 1. AH agents introduced after 1950, except ethyl vinyl ether, contain fluorine. Agents such as ether, chloroform, trichloroethylene (Tdlene), cyclopropane, and fluoroxene (Fluoromar), which were once used, have been displaced by the newer fluorinated anesthetics. 

In the presence of catalysts, trichloroethylene is readily chlorinated to pentachloro- and hexachloroethane. Bromination yields l,2-dibromo-l,l,2-trichloroethane [13749-38-7]. The analogous iodine derivative has not been reported. Fluorination with hydrogen fluoride in the presence of antimony trifluoride produces 2-chloro-l,l,l-trifluoroethane [75-88-7] (8). Elemental fluorine gives a mixture of chlorofluoro derivatives of ethane, ethylene, and butane. 

The Vapour Phase Fluorination of Trichloroethylene with Cobalt Trifluoride and with Manganese Trifluoride, G. Fuller, M. Stacey, J. C. Tatlow, and C. R. Thomas, Tetrahedron, 18 (1962) 123-133. 

Tests showed that Teflon gaskets containing more than 0.35 wt% of sorbed trichloroethylene were potentially hazardous in contact with liquid fluorine. 

Mixtures of the tetraoxide with dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, trichloroethylene and tetrachloroethylene are explosive when subjected to shock of 25 g TNT equivalent or less [1], Mixtures with trichloroethylene react violently on heating to 150°C [2], Partially fluorinated chloroalkanes were more stable to shock. Theoretical aspects are discussed in the later reference [2,3], The effect of pressure on flammability limits has been studied [4],... 

Mixtures of liquid oxygen with dichloromethane, 1,1,1-trichloroethane, trichloroethylene and chlorinated dye penetrants 1 and T exploded violently when initiated with a blasting cap. Carbon tetrachloride exploded only mildly, and a partly fluorinated chloroalkane not at all. Trichloroethylene has been used for degreasing metallic parts before use with liquid oxygen, but is not safe. 

The data on the reactivities of trichloroethylene and tetrachloroethylene further illustrate the competitive effects of substitutions on the 1- and 2-positions of ethylene. Trichloroethylene is more reactive than either of the 1,2-dichloroethylenes but less reactive than vinylidene chloride. Tetrachloroethylene is less reactive than trichloroethylene—analogous to the difference in reactivities between vinyl chloride and 1,2-dichloroethylene. The case of polyfluor-oethylenes is an exception to the generally observed large decrease in reactivity with polysubstitution. Tetrafluoroethylene and chlorotrifluoroethylene show enhanced reactivity due apparently to the small size of the fluorine atoms. 

With the great commercial interest in chlorofluorocarbons, the addition of HF to unsaturated organic chlorides, particularly vinylic chlorides has received considerable industrial attention.4 3 13-19 While these reactions are more difficult to effect than those of simple alkenes and increasing halogen substitution about the C—C double bond decreases the alkene reactivity, the reactions of simple monochloroalkenes proceed at temperatures from -23 to +120 C and can give good yields. Trichloroethylene or 1,1,2-tri-chloropropene, on the other hand, require temperatures in excess of 200 C, and tetrahaloethylenes fail to react in the absence of a catalyst.3 However, substitution of fluorine for chlorine tends to facilitate HF addition.3... 

SAFETY PROFILE Confirmed carcinogen with experimental carcinogenic, neoplastigenic, and tumorigenic data. A deadly poison by intravenous route. Human systemic effects by inhalation lung fibrosis, dyspnea, and weight loss. Human mutation data reported. See also BERYLLIUM COMPOUNDS. A moderate fire hazard in the form of dust or powder, or when exposed to flame or by spontaneous chemical reaction. Slight explosion hazard in the form of powder or dust. Incompatible with halocarbons. Reacts incandescently with fluorine or chlorine. Mixtures of the powder with CCU or trichloroethylene will flash or spark on impact. When heated to decomposition in air it emits very toxic fumes of BeO. Reacts with Li and P. 

Trichloroethene Trichloroethylene A number of fluorinated hydrocarbons (e.g., Freons)... 

HFC-134a has been found to be especially useful as a substitute for CFC-12 in automobile air conditioners. A fairly direct preparation method is shown in eqs (7) and (8) TCE = trichloroethylene. The reactions shown are typically done separately in several reaction zones. HCFC-133a can be prepared using catalysts such as Cr/Mg [34], Cr203/A1F3 [35], AlCUF [36], Zn/fluorinated alumina [37], and Zn/Cr [38, 39]. 

BERILIO (Spanish) (7440-41-7) Powder forms explosive mixture in air. Contact with acids or alkalis causes evolution of explosive hydrogen gas. Forms shock-sensitive mixtures with some chlorinated solvents, such as carbon tetrachloride and trichloroethylene. Violent reaction with chlorine, fluorine, lithium, phosphorus. Incompatible with alkalis, chlorinated hydrocarbons, halocarbons, oxidizable agents, oxidizers. 

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