General Description
A clear colorless liquid with a characteristic odor. Denser (12.3 lb/gal) than water and slightly soluble in water. Hence sinks in water. Nonflammable under most conditions, but burns under extreme conditions. May cause illness by inhalation, skin absorption or ingestion. Used as a solvent, to make other chemicals, as a fumigant.
Reactivity Profile
A mixture of acetone and CHLOROFORM(67-66-3) in a residue bottle exploded. Since addition of acetone to CHLOROFORM(67-66-3) in the presence of base will result in a highly exothermic reaction, CHLOROFORM(67-66-3) is thought that a base was in the bottle. [MCA Case History 1661(1970)]. Powdered aluminum and carbon tetrachloride(also methyl chloride and CHLOROFORM(67-66-3) or mixtures of these chemicals) exploded when heated(to 153°C.) and by impact, [Chem. Eng. News 32:258(1954); UL Bull. Research 34(1945), ASESB Pot. Incid. 39(1968)]. An inadequately cooled addition of sodium to a CHLOROFORM(67-66-3)-methanol mixture (sodium methoxide) caused a violent explosion, [MCA Case History No. 693]. CHLOROFORM(67-66-3) is incompatible with dinitrogen tetraoxide, fluorine, sodium metal and alcohols, nitromethane, and triisopropylphosphine.
Air & Water Reactions
Slightly soluble in water. Dissolves in water to form a corrosive solution of hypochlorous acid which decomposes on standing to chlorine, oxygen, and chloric acid.
Hazard
A possible carcinogen. Toxic by inhalation;
anesthetic; prolonged inhalation or ingestion may
be fatal. It has been prohibited by FDA from use
in drugs, cosmetics, and food packaging, including
cough medicines, toothpastes, etc. Nonflammable.
Will burn on prolonged exposure to flame or high
temperature. Liver and embryo/fetal damage, and
central nervous system impairment.
Health Hazard
CHLOROFORM is classified as moderately toxic. Probable oral lethal dose for humans is 0.5 to 5 g/kg (between 1 ounce and 1 pint) for a 150 lb. person. The mean lethal dose is probably near 1 fluid ounce (44 g). It is a human suspected carcinogen. Also, it is a central nervous system depressant and a gastrointestinal irritant. It has caused rapid death attributable to cardiac arrest and delayed death from liver and kidney damage.
Potential Exposure
Chloroform was one of the earliest
general anesthetics, but its use for this purpose has been
abandoned because of toxic effects. Chloroform is widelyused as a solvent (especially in the lacquer industry); in the
extraction and purification of penicillin and other pharmaceuticals; in the manufacture of artificial silk, propellents,
plastics, floor polishes, and fluorocarbons (R-22); and in
sterilization of catgut. Chemists and support workers as
well as hospital workers are believed to be at a higher risk
than the general population. Chloroform is widely distributed in the atmosphere and water (including municipal
drinking water primarily as a consequence of chlorination).
A survey of 80 American cities by EPA found chloroform
in every water system in levels ranging from ,0.3 to
311 ppb.
Fire Hazard
Container may explode in the heat of fire. When heated CHLOROFORM liberates phosgene, hydrogen chloride, chlorine and toxic and corrosive oxides of carbon and chlorine. Chloroform explodes when in contact with aluminum powder or magnesium powder or with alkali metals (e.g., lithium, sodium, and potassium) and dinitrogen tetroxide. CHLOROFORM reacts vigorously with acetone in the presence of potassium hydroxide or calcium hydroxide. CHLOROFORM is oxidized by strong oxidizers such as chromic acid forming phosgene and chlorine. CHLOROFORM reacts vigorously with triisopropylphosphine. CHLOROFORM develops acidity from prolonged exposure to air and light.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is recommended.
Shipping
UN1888 Chloroform, Hazard Class: 6.1; Labels:
6.1-Poisonous materials.
Incompatibilities
Though nonflammable, chloroform
decomposes to form hydrogen chloride, phosgene, and
chlorine upon contact with a flame. Chloroform decomposes slowly in air and light. Reacts violently with strong
caustics (bases), strong oxidants, chemically active metals
(especially powders), such as aluminum, lithium, magnesium, potassium, and sodium, causing fire and explosion
hazard. Attacks plastic, rubber, and coatings. Corrodes iron
and other metals in the presence of moisture.
Waste Disposal
Incineration, preferably after
mixing with another combustible fuel. Care must be exercised to assure complete combustion to prevent the formation of phosgene. An acid scrubber is necessary to remove
the halo acids produced.
Where possible it should be recovered, purified by distillation, and returned to the supplier.
Physical properties
Chloroform is a clear, colorless liquid with a pleasant odor and sweet burning taste. It is used to make hydrochloroflurocarbons (HCFCs), as a solvent for organic chemicals, and in chemical synthesis. Its use in many commercial products has been eliminated in recent decades because of its toxic and carcinogenic properties. It was once used extensively as an anesthetic, in medicines, in dry cleaning, and in refrigerants.
Definition
A colorless volatile liquid formerly used as an
anesthetic. Now its main use is as a solvent
and raw material for making other chlorinated compounds. Trichloromethane is
made by reacting ethanal, ethanol, or
propanone with chlorinated lime.
Definition
ChEBI: A one-carbon compound that is methane in which three of the hydrogens are replaced by chlorines.
Production Methods
Chloroform was first synthesized by treating acetone or ethanol with calcium hypochlorite or sodium hypochlorite bleaching powder. Chlorination of ethanol produces acetaldehyde and then trichloroacetaldehyde. Acetaldehyde yields chloroform and the formate ion by action of hydroxide ion. Acetone is chlorinated to trichloroacetone, which then splits into chloroform and the acetateion. The modern industrial preparation of chloroform involves the chlorination of methane or methyl chloride, CH3Cl, using heat to substitute the chlorine atoms for hydrogen. The reaction is carried out at approximately 500°C. Hydrochlorination by reacting methanol and hydrogen chloride can also be used to produce chloroform.
Brand name
Ametuss;Benafed;Benatuss;Benyphed;Broncho-rivo syrup;Chlor-histine;Codacol;Codimal dm;Co-specto;Cotrol-d;Cyprol expectrant;Dalet;Dectuss;Eludril;Expec-c;Fk-tussex;Guanor;Histalix;Kentuss;Linctuss;Mc 3;Muflin;Nagalyn;Notose;Orthos kavident;Panosoma;Penta-zine;Phenacol-dm;Phenatuss;Phlogarol;P-m-z;Promex;Rexahisine.
World Health Organization (WHO)
Chloroform was formerly widely used in pharmaceutical
preparations as a solvent and preservative as well as for its anaesthetic and
flavouring properties. By the late 1970s reservations concerning its safety,
including positive results in a carcinogenicity screening programme sponsored by
the National Cancer Institute in the USA, had led to considerable restrictions in its
use in pharmaceutical preparations. While many pharmaceutical products
containing chloroform have been withdrawn or reformulated to exclude this
substance, it may still be incorporated in toothpastes and other specified products
in some countries, subject to statutorily-imposed concentration limits.
(Reference: (IARCCD) Chloroform: IARC Monograph, 20(20), 401-427, 1979)
Flammability and Explosibility
Chloroform is noncombustible. Exposure to fire or high temperatures may lead to formation of phosgene, a highly toxic gas.
Chemical Reactivity
Reactivity with Water No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Industrial uses
Chloroform (CHC13) is the name given to trichloromethane, CHC13, because of its supposed relation to formic acid. A colorless liquid, half as dense as water and of about the same viscosity, chloroform has a heavy, ether-like odor and a burning sweetness of taste, being about 40 times as sweet as cane sugar. It is almost insoluble in water, but it is freely miscible with organic solvents and is an important solvent for gums, resins, fats, elements such as sulfur and iodine, and a wide variety of organic compounds. Common synonyms are trichloromethane, trichloroform, freon 20, Cobehn Spray-Cleaner solvent, formyl trichloride, methane trichloride, methenyl trichloride, and methyl trichloride. Chloroform is nonflammable and does not form explosive mixtures at atmospheric temperatures and pressures. It is used primarily in the production of Chlorofluorocarbon (CFC-22) and plastics like vinyl chloride. Other uses include extraction and purification of some antibiotics, alkaloids, vitamins, and flavors. It has been used as a solvent in lacquers, floor polishes, artificial silk manufacture, resins, fats, greases, gums, waxes, adhesives, oils, and rubber; used as a solvent in photography and dry cleaning; used in fire extinguishers; and used in the preparation of dyes and pesticides. It also was once used as a general anesthetic in surgery but has been replaced by less toxic, safer anesthetics, such as ether. It now has limited use.
Chloroform evaporates quickly and in its concentrated gaseous form, it will tend to settle to the ground before dispersing. It produces poisonous gas in a fire and is unstable when exposed to air, light, and/or heat, which cause it to break down to phosgene, hydrochloric acid, and chlorine. When heated to decomposition, chloroform emits toxic fumes of hydrochloric acid and other chlorinated compounds. Chloroform is produced by reaction of chlorine with ethanol and by the reduction of carbon tetrachloride with moist iron.
Carcinogenicity
Chloroform is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
Environmental Fate
Biological. An anaerobic species of Clostridium biodegraded chloroform (a metabolite of
carbon tetrachloride) by reductive dechlorination yielding methylene chloride and unidentified
products (G?lli and McCarty, 1989). Chloroform showed significant degradation with gradual
adaptation in a static-culture flask-screening test (settled domestic wastewater inoculum)
conducted at 25 °C. At concentrations of 5 and 10 mg/L, complete degradation was observed at
the end of the third subculture period (28 d). The amount lost due to volatilization after 10 d was
6–24% (Tabak et al., 1981).
Photolytic. Complete mineralization was reported when distilled deionized water containing
chloroform (118 ppm) and 0.1 wt % titanium dioxide as a catalyst was irradiated with UV light.
Mineralization products included carbon dioxide and HCl (Pruden and Ollis, 1983).
Photocatalyzed mineralization of chloroform in the presence of titanium dioxide as catalyst occurred at a rate of 4.4 ppm/min/gm catalyst (Ollis, 1985). Titanium dioxide suspended in an
aqueous solution and irradiated with UV light (λ = 365 nm) converted chloroform to carbon
dioxide at a significant rate. Intermediate compounds were not identified (Matthews, 1986).
Chemical/Physical. Matheson and Tratnyek (1994) studied the reaction of fine-grained iron
metal in an anaerobic aqueous solution (15 °C) containing chloroform (107 μM). Initially,
chloroform underwent rapid dehydrochlorination forming methylene chloride and chloride ions.
As the concentration of methylene chloride increased, the rate of reaction appeared to decrease.
After 140 h, no additional products were identified. The authors reported that reductive
dehalogenation of chloroform and other chlorinated hydrocarbons used in this study appears to
take place in conjunction with the oxidative dissolution or corrosion of the iron metal through a
diffusion-limited surface reaction.
storage
In the presence of light, chloroform undergoes autoxidation to generate phosgene; this can be minimized by storing this substance in the dark under nitrogen. Commercial samples of chloroform frequently contain 0.5 to 1% ethanol as a stabilizer.
Purification Methods
It reacts slowly with oxygen, or oxidising agents, when exposed to air and light, giving, mainly, phosgene, Cl2 and HCl. Commercial CHCl3 is usually stabilized with up to 1% EtOH or of dimethylaminoazobenzene. Simplest purifications involve washing with water to remove the EtOH, drying with K2CO3 or CaCl2, refluxing with P2O5, CaCl2, CaSO4 or Na2SO4, and distilling. It must not be dried with sodium. The distilled CHCl3 should be stored in the dark to avoid photochemical formation of phosgene. In an alternative purification, CHCl3 (500mL) was shaken (mechanically) with several small portions of 12% H2SO4 for 1hour, washed thoroughly with water, saturated NaHCO3, washed again with water, and dried over CaCl2 or K2CO3 (100g) for 1hour before filtering and distilling. After further drying for a short time over P2O5, the CHCl3 was redistilled and stored over Drierite in the dark [Reynolds & Evans J Am Chem Soc 60 2559 1938]. EtOH can be removed from CHCl3 by passage through a column of activated alumina, or through a column of silica gel 4-ft long by 1.75-in diameter at a flow rate of 3mL/minute. (The alumina column, which can hold about 8% of its weight of EtOH, is regenerated by air drying and then heating at 600o for 6hours. It is pre-purified by washing with CHCl3, then EtOH, leaving in conc H2SO4 for about 8hours, washing with water until the washings are neutral, then air drying, followed by activation at 600o for 6hours. Just before use it is reheated for 2hour at 154o.) [McLaughlin et al. Anal Chem 30 1517 1958.] Carbonyl-containing impurities can be removed from CHCl3 by percolation through a Celite column impregnated with 2,4-dinitrophenylhydrazine (DHNP), phosphoric acid and water. (Prepared by dissolving 0.5g DHNP in 6mL of 85% H3PO4 by grinding together, then mixing with 4mL of distilled water and 10g of Celite.) [Schwartz & Parks Anal Chem 33 1396 1961]. Chloroform can be dried by distillation from powdered type 4A Linde molecular sieves. For use as a solvent in IR spectroscopy, chloroform is washed with water (to remove EtOH), then dried for several hours over anhydrous CaCl2 and fractionally distilled. This treatment removes material absorbing near 1600 cm-1 . (Percolation through activated alumina increases this absorbing impurity). [Goodspeed & Millson Chem Ind (London) 1594 1967, Beilstein 1 IV 42.] Rapid purification: Pass through a column of basic alumina (Grade I, 10g/mL of CHCl3), and either dry by standing over 4A molecular sieves, or alternatively, distil from P2O5 (3% w/v). Store away from light (to avoid formation of phosgene) and use as soon as possible.
Toxicity evaluation
Chloroform in soil or surface water volatilizes readily; at
equilibrium, greater than 99% is expected to partition to the
atmosphere. Some wet deposition of atmospheric chloroform
may occur, but subsequent revolatilization is likely to be
extensive. Chloroform is not expected to partition significantly
to soils or sediments, because its affinity for organic carbon and
lipids is low. Compartmental partitioning has been reported to
be 99.1, 0.9, 0.01, and 0.01% in air, water, soil, and sediment,
respectively. The preferred target compartment in the environment
at equilibrium is the air compartment.
Chloroform is considered as nonbiodegradable in water.
Hydrolysis is an unimportant fate process at a neutral pH value and direct photolysis in water is not expected too. In surface
water, the principal removal process is volatilization with
estimated half-lives of 1.5 days and 9–10 days in a river and
a lake, respectively. Most studies have indicated little biodegradation
up to 25 weeks in aquatic systems under aerobic
conditions. The principal fate of chloroform at the soil surface
is temperature-dependent volatilization due to its volatile
nature and low soil adsorption.
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