Chloroethanes toxicity

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 . 

NIOSH. 1978. Current Intelligence Bulletin 27, chloroethanes review of toxicity. Cincinnati, OH National Institute for Occupational Safety and Health. PB85-119196. 

A major disadvantage of the Wacker chemistry using chloride catalysts is the production of chlorinated byproducts such as chloroethanal. These have to be removed since they are toxic and cannot be allowed in the wastewater. In the small recycle loop the catalyst solution is heated to 160 °C which leads to decomposition of chlorinated aldehydes under the influence of the metal chlorides. The traces going over the top in the gas/liquid separator have to be removed from the wastewater by different means. The toxicity inhibits biodegradation. Chlorine free catalysts have been studied but have not (yet) been commercialised. 

NIOSH Current Intelligence Bulletin 21. Chloroethanes Review of Toxicity, Pub. No. 78-181, p 22. DHEW (NIOSH), 1978... 

Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profile For Chloroethane, pp 1-145. US Department of Health and Human Services, Public Health Service, 1998... 

In short-term renal toxicity studies in rats gavage administration of 1,1,2,2-tetra-chloroethane caused renal toxicity as evidenced by an increased renal tubule cell labeling index, indicating replicative DNA synthesis. In 2-year studies 1,1,2,2-tetrachloroethane administered by gavage produced an increased incidence of hepatocellular carcinomas in mice but not in rats. In one epidemiological study of exposed army workers there was a slight increase in deaths due to genital cancer and leukemia. Exposure levels were not available,... 

Similarly, in another long-term carcinogenicity study (Quast et al., 1988), very slight microscopic hepatotoxic changes were observed in rats of both sexes at 6, 12 and 18 months, but no more at 24 months after exposure to 1500 ppm [8190 mg/m ] 1,1,1-tri-chloroethane for 6 h per day on five days per week for two years. No toxic changes were observed in mice. 

Caution. Boron trifluoride etherate is a moisture-sensitive liquid. Small amounts of highly toxic HF and flammable chloroethane and diethyl ether are produced during the synthesis. Benzeneacetonitrile is toxic by inhalation and skin absorption. It also an eye irritant. Appropriate precautions must be taken, and an efficient hood must be used. 

The IUPAC rules for naming aldehydes append the suffix -al to the parent name. The aldehyde carbon is always the first carbon in the chain, so a locant is not necessary. The simplest aldehyde, methanal, is commonly known as formaldehyde, a highly toxic gas used to preserve biological specimens. Ethanal is the next aldehyde, although most organic chemists call it acetaldehyde. 2,2,2-Tri-chloroethanal, more commonly known as chloral, reacts with water to form the sedative chloral hydrate. Phenylmethanal, more commonly known as benzalde-hyde, is used as artificial cherry or almond flavoring. Nomenclature examples of aldehydes are shown in Figure 11.34. 

SAFETY PROFILE An intense irritant to dssue, skin, and eyes. Flammable by chemical reaction. Ignites or explodes with heat or grinding. Explosive reaction with moisture, chromium trioxide, potassium chlorate, halocarbons (e.g., l,l-diethoxy-2-chloroethane), oxidants, sodium nitrite, air. Can become explosive in storage. Violent reaction with dinitrogen tetraoxide. Will react with water or steam to produce heat and toxic and corrosive fumes of sodium hydroxide and ammonia. When heated to decomposition it emits highly toxic fumes of NH3 and Na20. See also AMIDES. 

Information is also limited on the role of 1,1,1-trichloroethane metabolites in the compound s toxicity. Reactive metabolites are important in the carcinogenicity of other chloroethanes (i.e.,... 

Vinyl chloride, the base for polyvinyl chloride (PVC), is important in the plastics industry. Also called chloroethane or chloroethylene, vinyl chloride s past uses included propellants for pesticides and reagents in trichloroethylene production. PVC also has uses in apparel, building and construction, electrical components, homes, packaging, recreation, transportation, and numerous other aspects of modem society (Warren et al. 1978). Vinyl chloride, a toxic gas, causes numerous physical symptoms (see Table 17-3). Table 17-4 lists psychiatric symptoms attributed to vinyl chloride exposures. 

Ethylene Dichlorlde. 1,2-Dichloroethane syrn-di -chloroethane ethylene chloride EDO Dutch liquid Bro-tide. C2H,CI2 mol wt 98.96. C 24.27%, H 4.07%, Cl 71.66%. CICHjCHjCl. Made from ethylene and chlorine also from acetylene and HCI Reilstein 1, 4 0918). Manuf Faith, Keyes Clark s Industrial Chemicals, F. A. Lowen-htim, M. K. Moran, Eds. (Wiley -Interscience, New York, 4th ed., 1975) pp 392-396. Toxicity data Smyth el aL, Am. Ind. Hyg. Assoc. J. 30,470 (1969). Review of carcinogenicity studies I ARC Monographs 20, 429-444 (1979). 

Contact with amphoteric metals such as aluminum, zinc, and tin generates hydrogen, which is flammable, forming explosive mixtures in air. When heated with tetra-chloroethane or 1,2-dichloroethylene, potassium hydroxide generates chloroacetylene, a toxic gas that ignites spontaneously and explodes in air. 

Bis(l-chloroethyl) ether [ 1, l -oxybis( 1 -chloroethane] [6986-48-7] C4H8CI2O 143.02 Cl Cl 1 1 H3C—CH—0—CH—CH3 Low inhalation toxicity toxicity data not available expected to cause anesthesia at concentrations >2% in air by volume caused cancers in mice at the site of application when given subcntaneonsly Combustible liquid flash point data not available... 

Features Chemically inert low surf, tens. nonhydrolyzable Properties Colorless to straw clear to hazy liq. sol. in IPA, ethanol, 1,1,1-chloroethane, xylene, toluene insol. in water, heptane, min. spirits m.w. 6500 sp.gr. 1.10 dens. 8.4 Ib/gal vise. 440 cst f.p. 18 C HLB8.4 flash pt. (PMCC) > 300 F 100% act. 58% silicone Toxicology Very low order of toxicity... 

In 1939, P. Muller discovered the insecticidal properties of dichloro-diphenyl-tri-chloroethane (DDT). High insecticidal toxicity and low mammalian toxicity made it worldwide the most successful insecticide for years. P. Muller was awarded the Nobel Prize for Medicine in 1948. Within a few years the production grew to more than 100 000 tonnes per year. It was used in huge quantities against moths, lice, mosquitos, flies, etc., many of them transmitters of diseases such as malaria, typhus, cholera. These diseases could be reduced drastically. 

Ultrasonic degreasing is known to produce excellent results for small components. Trichloroethylene, acetone, methylene chloride, tetrachloroethylene, and so on are among good solvents for ultrasonic degreasing. Alcohol, gasoline, and paint thinners are not recommended. An effective solvent is 1,1,1-tri-chloroethane because of its low toxicity and flammability. To verify the cleanliness of a surface that has been degreased, water or dyne liquids are used. If a drop of water forms a film of the surface, then it is free from contamination. If a drop retains its shape, degreasing of the surface must be repeated. 

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