Preparation, Properties, And Uses Of Trichloromethane
Trichloromethane CHCl3 also known as chloroform is an organic compound and e which is involved in the production of refrigerants. It is a volatile, dense, and colourless liquid with a very strong and sweet ether-like smell.
It produces a very lethal gas when broken down and has a very powerful sedative, anesthetic, anxiolytic and euphoriant effect on the body when ingested or inhaled and is used in the production of medications.
The major percentage of the emitted trichloromethane is gotten from natural habitats and the totality of its global flux via the environment is at 660,000 tonnes annually. As of 2002, 302,800 tonnes of trichloromethane was produced annually and 4,000 tonnes of it are released into the environment via wasted waters and evaporation.
The individual preparation of trichloromethane has been carried out by different scientists since 1830.
American physician Samuel Guthrie, London scientist Robert Mortimer Glover, French chemist Jean-Baptiste Dumas, German pharmacist Frankfurt Oder, and Scottish obstetrician James Simpson are some of the people who independently prepared this compound around that time.
However, it was Simpson’s audacity to test the anesthetic ability of this liquid on humans in 1847 that brought it into the limelight and made the pharmaceutical industry start using it in medicines.
Preparation Of Trichloromethane
Trichloromethane is produced along with sodium hydroxide and sodium acetate through the haloform reaction which involves the reaction of sodium hypochlorite and acetone.
3 NaClO + (CH3)2CO = CHCl3+ 2 NaOH + CH3COONa
Trichloromethane is prepared by heating chloral hydrate and sodium hydroxide.
C2H3Cl3O2 + NaOH = CHCl3 + CHNaO2 + H2O
Industrially, trichloromethane is prepared by the chlorination of either methane or chloromethane.
In this process, methane is mixed with chlorine to form chloromethane which is mixed with chlorine to form dichloromethane.
Dichloromethane is then mixed with chlorine to form Trichloromethane.
CH4 + Cl2 = CH3Cl + HCl
CH3Cl + Cl2 = CH2Cl2 + HCl
CH2Cl2 + Cl2 = CHCl3 + HCl
Trichloromethane can also be formed as a by-product during water chlorination.
Trichloromethane is prepared by the reaction of carbon tetrachloride with dihydrogen.
CCl4 + H2 = CHCl3 + HCl
Trichloromethane is produced by heating bleaching powder and either ethanol or acetone.
CaOCl2 + C2H5OH = CHCl3 + CaCl2 + Ca(OH)2 + Ca(HCOO)2
Chemical Properties Of Trichloromethane
Trichloromethane undergoes chlorination to produce carbon tetrachloride.
CHCl3 + Cl2 = CCl4 + HCl
Trichloromethane reacts with hydrofluoric acid in the presence of mixed antimony halides from hydrogen chloride and monochlorodifluoromethane which is then changed into polytetrafluoroethylene – a major constituent in the production of Teflon.
CHCl3 + 2 HF = CHCIF2 + 2 HCl
Trichloromethane reacts with phenol and sodium hydroxide to form salicylaldehyde.
Trichloromethane is treated with phenols in the presence of sodium hydroxide to form hydroxybenzaldehyde in the Reimer-Tiemann reaction.
Trichloromethane gently changes when in the atmosphere to a poisonous compound Phosgene and releases hydrochloric acid.
2 CHCI3 + O2 = 2 COCl2 + 2 HCl
As a reagent, trichloromethane reacts with aqueous sodium hydroxide in the presence of a transfer catalyst to form dichlorocarbene.
Trichloromethane reacts with silver powder to produce acetylene gas.
2CHCl3 + 6Ag = C2H2 + 6AgCl
Trichloromethane reacts with sodium hydroxide to form sodium formate.
Trichloromethane reacts with acetone in the presence of sodium hydroxide to produce chloretone.
It is reduced when treated with Zinc in the presence of water or acid.
Trichloromethane is heated with potassium hydroxide to produce potassium hydrate.
It produces an unpleasant smell when heated with carbylamines.
Trichloromethane is treated with concentrated nitric acid to form chloropicrin.
Physical Properties Of Trichloromethane
Trichloromethane is a colorless, volatile, and dense liquid with a strong and sweet odor. It is non-flammable, miscible in ligroin, alcohol, and diethyl ether, and is partially soluble in water and benzene.
It boils at 61.15°C (142.07°F), melts at -63.5°C (-82.3°F) and decomposes at 450°C.
It also has a molar mass of 119.37 g-mol-1, a density of 1.49 gm-3, and a viscosity of 20°C.
Uses Of Trichloromethane
• It is used in formulating pesticides.
• It is used in the production of propellants and resins.
• It is used as a component in hydrogen bonding.
• It is used to preserve anatomical and biological specimens.
• In the pharmaceutical industry, it is used in the production of penicillin, as an anesthetic, and as a component in the production of cough syrups.
• It is used as a reagent.
• Due to its anesthetic ability, it is used by criminals to knock their victims out, or even murder them.
• It is used in manufacturing other chemicals.
• It is used in root canal procedures.
• It is used as a solvent in oils, fats, and waxes.
• It is used in the production of organic compounds.
Health Concerns
Chloroform is carcinogenic so long-term exposure could lead to cancer. Exposure to the eye can also cause eye irritation.
If it touches your skin, it removes fat from the affected areas which leads to the production of sores. If inhaled or ingested, it could lead to a deep coma.
However, to avoid trichloromethane accidents, ethanol is added to it to stabilize it and there has been a restriction on its use due to the negative health effects associated with it.
Eating foods that contain chloroform and breathing contaminated air are some other ways by which you can also be exposed to the substance naturally.
