What Is Trichloroethylene Definition Formula Reactions and Applications
Trichloroethylene was first prepared in 1864. It is man-made and does not exist in the atmosphere naturally. Trichloroethylene emissions can mainly come from three sources: processing, transport, and consumption. It may also be released to the atmosphere by evaporation from and during the manufacture of adhesive glues, paints, coatings, and other chemicals.
In this article, we will study TCE trichloroethylene, trichloroethylene products, TCE in water, and the use of trichloroethylene in detail.
TCE Trichloroethylene
IUPAC name of Trichloroethylene (TCE) is Trichloroethene with a molecular formula of C2HCl3. It is a transparent, mobile, colourless liquid with an ether-like odour.
Density -1.46g/cm3
Molecular weight-131.4 g/mol
Boiling point- 87.2 C
Melting point- -73C
Use of Trichloroethylene
TCE is used in the manufacture of various fluorocarbon refrigerants.
As an efficient degreaser, TCE was used for machinery parts and equipment. It is used to extract grease from fabricated pieces of metal and certain textiles as a solvent (trichloroethylene solvent).
TCE has also been used to clean kerosene-fueled rocket engines (trichloroethylene military use).
It is also used in adhesives, paint removers, fluids for typewriter correction, and spot removers as an ingredient.
Used for the production of 100% ethanol by removing residual water.
Trichloroethylene Structure
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Physical Properties of Trichloroethylene
The Chemical Reaction of Trichloroethylene
4 C2HCl3+ 9 O2 → 8 CO2 + 2 H2O + 6 Cl2
The Industrial History of TCE
It is used as a solvent for organic solvents.
It is used to extract vegetable oil from plant materials.
Used in the food industry for coffee decaffeination and for the preparation of flavouring extract from spices.
It is used as anaesthesia administered with nitrous oxide. It is very effective even in low concentration and thus considered a better anaesthetic than chloroform and ether
TCE in Water and Soil
TCE dissolves only a little in water but can remain in groundwater for a long time.
TCE quickly evaporates from surface water, so it is commonly found as a vapour in the air.
TCE evaporates less easily from the soil than surface water It sticks to particles and remains for a long time.
TCE may stick to particles in water and settle in bottom sediments.
How are People Exposed to TCE?
Breathing air in the home contaminated with TCE vapours.
Drinking, swimming, or showering in water that has been contaminated with TCE.
Contact with soil contaminated with TCE.
Contact with the skin and/or breathing in vapours while using TCE in-home or work
TCE and Human Health
Small amounts of TCE can cause headaches, irritation of the lungs, dizziness, poor coordination, and attention problems.
Impaired heart function, unconsciousness, and death can be caused by breathing large quantities of TCE.
Breathing large quantities of TCE for a long time can cause damage to the nerves, kidneys, and liver.
Nausea, liver damage, unconsciousness, reduced heart function, and death can be caused by consuming significant quantities of TCE.
Drinking large amounts of TCE for long periods of time may cause impaired immune system function, and impaired fetal development (though the extent is not yet clear).
Skin contact with TCE for short periods of time may cause skin rashes.
Did You Know?
Some studies in mice and rats have suggested that high levels of TCE may cause kidney, liver, or lung cancer. Some studies of people exposed over long periods to high levels of TCE in drinking water or in the workplace air have found evidence of increased cancer rates.
The International Agency for Cancer Research has established that TCE is likely to be carcinogenic in humans.
FAQs on Trichloroethylene Structure Properties Preparation and Uses
1. What is trichloroethylene?
Trichloroethylene (TCE) is a colorless, nonflammable chlorinated hydrocarbon with the chemical formula C2HCl3 used mainly as an industrial solvent and degreasing agent. It belongs to the class of chlorinated alkenes and contains a carbon–carbon double bond. TCE has a mildly sweet odor and has been widely used in metal cleaning, chemical manufacturing, and extraction processes. Due to its toxicity and environmental persistence, its use is now regulated in many countries.
2. What is the chemical formula and structure of trichloroethylene?
Trichloroethylene has the molecular formula C2HCl3 and consists of two carbon atoms joined by a double bond with three chlorine atoms attached. Its structural features include:
- A C=C double bond (alkene functional group)
- Three chlorine (Cl) atoms substituting hydrogen atoms
- One remaining hydrogen atom
The condensed structural formula is commonly written as ClCH=CCl2. The presence of electronegative chlorine atoms influences its polarity and reactivity.
3. What type of compound is trichloroethylene?
Trichloroethylene is a halogenated alkene, specifically a chlorinated hydrocarbon containing a carbon–carbon double bond. It is classified as:
- An unsaturated hydrocarbon (because of the C=C bond)
- A haloalkene (due to chlorine substituents)
- A volatile organic compound (VOC)
Its unsaturation allows it to undergo addition reactions, while the chlorine atoms affect its physical and chemical properties.
4. How is trichloroethylene produced industrially?
Trichloroethylene is produced industrially by chlorination of hydrocarbons such as ethylene or by dehydrochlorination of tetrachloroethane. A simplified reaction pathway involves:
- Chlorination of ethylene (C2H4) to form chlorinated intermediates
- Further chlorination and elimination steps
One representative dehydrochlorination reaction is:
C2H2Cl4 → C2HCl3 + HCl
where tetrachloroethane loses hydrogen chloride to form trichloroethylene.
5. What are the physical properties of trichloroethylene?
Trichloroethylene is a colorless, volatile liquid with a sweet odor and a boiling point of about 87°C. Key physical properties include:
- Molecular mass: 131.39 g·mol-1
- Boiling point: ~87°C
- Density: ~1.46 g·cm-3 (at 20°C)
- Low solubility in water but high solubility in organic solvents
Its high density and volatility make it effective for vapor degreasing in industrial applications.
6. What are the main uses of trichloroethylene?
Trichloroethylene is mainly used as an industrial solvent for metal degreasing and chemical processing. Common uses include:
- Vapor degreasing of metal parts
- Extraction solvent in chemical industries
- Intermediate in the production of other chemicals such as refrigerants
Due to environmental and health concerns, many of these uses are now restricted or replaced with safer alternatives.
7. Is trichloroethylene toxic?
Yes, trichloroethylene is toxic and classified as a human carcinogen. Health risks associated with TCE exposure include:
- Central nervous system depression (dizziness, headaches)
- Liver and kidney damage
- Increased risk of certain cancers with long-term exposure
Because of its toxicity and volatility, occupational exposure limits and environmental regulations strictly control its use and disposal.
8. How does trichloroethylene react chemically?
Trichloroethylene undergoes addition reactions at its carbon–carbon double bond and substitution reactions involving chlorine atoms. Typical reactions include:
- Hydrogenation: C2HCl3 + H2 → C2H2Cl4 (addition across C=C)
- Oxidation in air forming phosgene (COCl2) under certain conditions
The presence of electron-withdrawing chlorine atoms influences its reactivity and stability.
9. What is the difference between trichloroethylene and tetrachloroethylene?
The main difference is that trichloroethylene (C2HCl3) contains one hydrogen atom, while tetrachloroethylene (C2Cl4) contains no hydrogen atoms. Key distinctions include:
- TCE: C2HCl3, one H atom, unsaturated alkene
- PCE (tetrachloroethylene): C2Cl4, fully chlorinated alkene
- PCE is widely used in dry cleaning
Both are chlorinated solvents, but their chemical composition and some physical properties differ due to hydrogen substitution.
10. Why is trichloroethylene considered an environmental contaminant?
Trichloroethylene is considered an environmental contaminant because it is persistent, toxic, and can contaminate soil and groundwater. Environmental concerns include:
- High mobility in groundwater due to its density
- Slow biodegradation in anaerobic conditions
- Formation of harmful breakdown products such as vinyl chloride
Because TCE is a volatile organic compound (VOC) and potential carcinogen, it is closely monitored in drinking water and industrial waste sites.
