Properties

General

Name Chloroform
Chemical formula CHCl3
Appearance Colourless liquid

Physical

Formula weight 119.4 amu
Melting point 210 K (-63 °C)
Boiling point 335 K (61 °C)
Density 1.48 ×103 kg/m3 (liquid)
Solubility slightly soluble in water

Thermochemistry

ΔfH0gas -89.7 kJ/mol
ΔfH0liquid -120.9 kJ/mol
ΔfH0solid ? kJ/mol
S0gas, 1 bar ? J/mol·K
S0liquid, 1 bar ? J/mol·K
S0solid ? J/mol·K

Safety

Ingestion Causes nausea and vomiting, with possible dizziness or hallucination.
Inhalation In high concentration, may cause dizziness, unconsciousness, coma, and possible heart failure.
Skin Mild irritant.
Eyes Strongly irritating, producing tearing and burning sensations.
More info Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used.

Disclaimer and references

Chloroform (also known as trichloromethane and methyl trichloride) is a chemical compound with formula CHCl3. It is a colorless liquid with a pleasant, nonirritating odor and a slightly sweet taste. It does not support combustion in air, although it will burn when mixed with more flammable substances.

Table of contents
1 History
2 Production
3 Uses
4 Safety

History

Chloroform was first produced independently and simultaneously in 1831 by Justus von Liebig and the French chemist Eugene Souberain, who produced chloroform through the action of bleach upon acetone or ethanol.

In 1847, the Edinburgh obstetrician James Young Simpson first used chloroform to effect general anesthesia during childbirth. The use of chloroform during surgery expanded rapidly thereafter, especially in Europe. In the United States, chloroform did not replace ether as an anesthetic until the beginning of the 20th century.

Production

Industrially, chloroform is produced by heating a mixture of chlorine and either methyl chloride or methane to 400-500°C. At this temperature, a series of chemical reactions occur, converting the methane or methyl chloride to progressively more chlorinated compounds.

CH4 + Cl2CH3Cl + HCl
CH3Cl + Cl2CH2Cl2 + HCl
CH2Cl2 +Cl2 → CHCl3 + HCl
CHCl3 + Cl2CCl4 + HCl

The output of this process is a mixture of the four chloromethanes, methyl chloride, methylene chloride, chloroform, and carbon tetrachloride, which are then separated by distillation.

Uses

In the late 19th and early 20th centuries, chloroform was used as an inhaled anesthetic during surgery. However, safer, more flexible drugs have entirely replaced it in this role. The major use of chloroform today is in the production of the
freon refrigerant R-22. However, as the Montreal Protocol takes effect, this use can be expected to decline as R-22 is replaced by refrigerants that are less likely to cause ozone depletion.

Smaller amounts of chloroform are used as a solvent in the pharmaceutical industry, and for producing dyes and pesticides.

Safety

As might be expected from its use as an anesthetic, inhaling chloroform vapors depresses the central nervous system. Breathing about 900 parts of chloroform per million parts air (900 ppm) for a short time can cause dizziness, fatigue, and headache. Chronic chloroform exposure may cause liver and kidney damage, and some people develop sores when the skin is immersed in chloroform. Approximately 10% of the population has an allergic reaction to chloroform that produces a fever of around 40°C (104°F) upon exposure.

Animal studies have shown that miscarriages occur in rats and mice that have breathed air containing 30 to 300 ppm chloroform during pregnancy and also in rats that have ingested chloroform during pregnancy. Offspring of rats and mice that breathed chloroform during pregnancy have a higher incidence of birth defects, and abnormal sperm have been found in male mice that have breathed air containing 400 ppm chloroform for a few days. The effect of chloroform on reproduction in humans is unknown.

Chloroform once appeared in toothpastes, cough syrups, ointments, and other pharmaceuticals, but it has been banned in consumer products in the United States since 1976.