Trichloromethane, chemical formula CHCl ≮, is an organic compound, also known aschloroform, colorless transparent liquid, with special smell, sweet taste, high refractive index, incombustible, density greater than water, volatile。It is the product that three hydrogen atoms in the methane molecule are replaced by chlorine atoms。It is sensitive to light. When exposed to light, it reacts with oxygen in the air and gradually decomposes to produce highly toxic phosgene (carbonyl chloride) and hydrogen chloride.1%~2% ethanol can be added as stabilizer during storage[1]。It is miscible with ethanol, benzene, ether, petroleum ether, carbon tetrachloride, carbon disulfide and oils.Because of its unique physical and chemical properties, this compound is widely used in industry, medicine and other fields.
On October 27, 2017, in the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization, chloroform was included in the list of Category 2B carcinogens.[2]On July 23, 2019, chloroform was included in the list of toxic and harmful water pollutants (the first batch)[3]。On December 29, 2022, dichloromethane was included in the list of new pollutants under key control (version 2023), and its production and use were strictly regulated.[4]
Trichloromethane (precursor - 2) is controlled by the public security department according to the Regulations on the Safety Management of Dangerous Chemicals and the Regulations on the Management of precursor chemicals.[5]
Physical and chemical properties
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physical property
Appearance and properties: colorless transparent liquid, highly volatile, with special smell.
Melting point: - 63.5 ℃[6]
Density: 1.48 g/cmthree[6]
Boiling point: 61.3 ℃[6]
Saturated vapor pressure: 13.33 kPa (10.4 ℃)[6]
Critical temperature: 263.4 ℃[6]
Critical pressure: 5.47 MPa[6]
Solubility: insoluble in water, soluble in alcohol, ether, benzene
chemical property
Under light, it will be gradually oxidized to produce highly toxic phosgene when encountering air, so it needs to be stored in a sealed brown bottle.A small amount of ethanol is often added to destroy the phosgene that may be generated.It is not easy to burn. Under the action of light, it can be oxidized by oxygen in the air to hydrogen chloride and highly toxic phosgene.In methyl chloride, it is most likely to be hydrolyzed to monochloroformic acid and HCl, with poor stability and thermal decomposition at higher temperatures.Hydrolysis of chloroform refers to the process of chemical reaction with water to produce reaction products.The hydrolysis of chloroform involves several steps.First, chloroform will generate monochloroformic acid (HCOCI) and hydrochloric acid in water. The chemical equation of hydrolysis reaction is as follows:
CHCIthree+ HtwoO = HCOCI +2HCI
Monochloroformic acid is a weak acid that can further react with water to produce carbon dioxide and hydrochloric acid.Carbon dioxide is a gas that will escape from the solution, while hydrochloric acid will exist in water, increasing the acidity of the solution.In addition to hydrolysis, chloroform can be further chlorinated to CClfour。
Molecular structural properties
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Refractive index (n20/D): 1.4459[7]
Molar volume (cmthree/mol）：79.5[7]
Isotonic specific volume (90.2K): 184.6[7]
Surface tension (dyne/cm): 28.9[7]
Polarization (10-24cmthree）：8.39[7]
Calculate chemical data
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Reference value for drainage parameter calculation (XlogP): 2.3
Number of hydrogen bond donors: 0
Number of hydrogen bond receptors: 0
Number of rotatable chemical bonds: 0
Number of tautomers: 0
Topological molecular polar surface area: 0
Number of heavy atoms: 4
Surface charge: 0
Complexity: 8
Number of isotope atoms: 0
Determine the number of atomic structure centers: 0
Number of uncertain atomic structure centers: 0
Determine the number of chemical bond structure centers: 0
Number of uncertain chemical bond structure centers: 0
Rats inhaled 2ppm of this product, 7h a day, 5d a week, for a total of 6 months, with liver and kidney tissue damage.
Mutagenicity
DNA inhibition: human Hela cell 19mmol/L.
Sister chromatid exchange: human lymphocytes 10mmol/L.
Micronucleus test: 4 mmol/kg by mouth in rats.
Out of program DNA synthesis: 1g/kg by mouth in rats.
DNA damage: human lung 100 μ mol/L (3h)
Teratogenicity
The lowest toxic dose (TDLo) of 1260 mg/kg was orally administered to rats 6~15 days after pregnancy, resulting in developmental malformations of musculoskeletal system.
The lowest toxic dose (TCLo) of 100ppm (7h) inhaled by rats 6~15d after pregnancy resulted in gastrointestinal malformation.
Inhalation of the lowest toxic dose (TCLo) of 100ppm (7h) 8~15d after pregnancy in mice caused craniofacial (including nose and tongue) malformations.
The lowest toxic dose (TDLo) of 41mg/kg was orally administered to rats for several generations, resulting in malformations of the genitourinary system.
carcinogenicity
IARC carcinogenicity review: G2B, suspected human carcinogen.[5]
Maximum optical absorption wavelength range of photolysis (nm): 220.9~296.3
Photooxidation half-life in water (h): 6.90 × 105~2.80 × 107
Photooxidation half-life in air (h): 623~6231
First order hydrolysis half-life (h): 3500
Other harmful effects
The substance is harmful to the environment and accumulates in groundwater.Its pollution behavior is mainly reflected in drinking water, but it can also cause pollution to food and vegetables.Damage the respiratory system of sensitive aquatic organisms.It is difficult to be biodegraded in the water environment.[5]
application area
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Chloroform, or chloroform, is an organic compound widely used in many fields.Its main application fields include industry, medicine, laboratory and other fields.
In industry, chloroform is widely used as a solvent. Its excellent solubility and volatility make it an ideal choice in many chemical reactions and production processes.It plays a key role in the manufacturing of coatings, glues, detergents and other products, helping to synthesize and stabilize the quality and performance of these products.It is also an organic synthetic raw material in industry, mainly used to produce Freon (F-21, F-22, F-23), dyes and drugs.Industrial products are usually added with a small amount of ethanol, so that the generated phosgene reacts with ethanol to generate non-toxic diethyl carbonate.Before using industrial products, a small amount of concentrated sulfuric acid can be added, shaken, washed, dried by calcium chloride or potassium carbonate, and then chloroform without ethanol can be obtained.
In medicine, it is often used as an anesthetic.However, because of its potential adverse effects on the heart and liver, it has been replaced by safer anesthetics.Nevertheless, chloroform is still used as a chemical reagent in some laboratories for specific experiments and analysis.It can be used as solvent and extractant for antibiotics, spices, oils, resins and rubber.It can be mixed with carbon tetrachloride to make non freezing fireproof liquid.It is also used for aerosol propellant, grain fumigant and standard solution for calibration temperature.
In addition, chloroform plays an important role in scientific research in the laboratory, which is used in organic synthesis, solvent extraction, analysis and testing.Its unique chemical properties make it an indispensable part of scientific research.
First aid measures
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Skin contact: Take off contaminated clothes immediately, and wash with plenty of flowing water for at least 15 minutes.Get medical attention.
Eye contact: immediately lift the eyelid, and thoroughly flush it with a large amount of flowing water or physiological saline for at least 15 minutes.Get medical attention.
Inhalation: quickly leave the site to a place with fresh air.Keep the respiratory tract unobstructed.If breathing is difficult, oxygen is needed.If breathing stops, perform artificial respiration immediately.Get medical attention.
Ingestion: drink enough warm water to induce vomiting.Get medical attention.
If poisoning symptoms have occurred, first call emergency services: if someone is suspected of being poisoned or exposed to chloroform, immediately call the local emergency number and request professional medical assistance.Then move the poisoned person to a ventilated area: if possible, move the poisoned person quickly to a well ventilated outdoor area to avoid further exposure to chloroform.If the poisoned person has difficulty breathing or stops breathing, perform cardiopulmonary resuscitation (CPR).When conducting CPR, ensure that it is conducted in a well ventilated place.The poisoned person may have hypothermia, so keep his/her body temperature, which can be covered with blankets or clothes.
Fire fighting measures
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Hazard characteristics: It can produce highly toxic phosgene when contacting with open fire or hot objects.Under the action of air, water and light, the acidity increases, so it is strongly corrosive to metals.
Extinguishing method: firefighters must wear filter type gas masks (full face masks) or isolated respirators, wear full body fire and gas clothing, and extinguish the fire upwind.
Extinguishing agent: water mist, carbon dioxide, sand.
Leakage emergency treatment
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Evacuate the personnel in the leakage contaminated area to a safe area quickly, isolate them, and strictly restrict access.It is recommended that emergency personnel wear self-contained positive pressure respirators and anti poison clothing.Do not touch the leakage directly.Cut off the leakage source as much as possible.
Small amount of leakage: absorb with sand, vermiculite or other inert materials.
Large amount of leakage: build a dike or dig a pit to receive.Cover with foam to reduce steam disaster.Transfer to tank car or special collector with pump, and recycle or transport to waste disposal site for disposal.
Operation, disposal, storage and transportation
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Operation precautions: closed operation, local exhaust.Operators must be specially trained and strictly abide by the operating procedures.It is recommended that operators wear direct gas masks (half masks), chemical safety goggles, anti poison penetration work clothes and anti chemical gloves.Prevent vapor leakage into the air of the workplace.Avoid contact with alkali and aluminum.Load and unload gently during transportation to prevent damage to packaging and containers.Provide leakage emergency treatment equipment.Empty containers may leave harmful substances.
Precautions for storage: store in a cool and ventilated warehouse.Keep away from kindling and heat sources.The storage temperature shall not exceed 30 ℃, and the relative humidity shall not exceed 80%.Keep container sealed.It shall be stored separately from alkali, aluminum and edible chemicals, and mixed storage is strictly prohibited.The storage area shall be equipped with leakage emergency treatment equipment and appropriate materials.
security information
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Safety terminology
S7：Keep container tightly closed.
Store in a tightly closed container.
S9：Keep container in a well-ventilated place.
Keep the container in a well ventilated place.
S23：Do not breathe gas/fumes/vapour/spray.
Do not breathe gas/smoke/vapor/spray.
S25：Avoid contact with eyes.
Avoid eye contact.
S26：In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
After eye contact, immediately flush with plenty of water and seek medical advice.
S33：Take precautionary measures against static discharges.
Take precautions against static electricity.
S36/37/39：Wear suitable protective clothing, gloves and eye/face protection.
Wear appropriate protective clothing, gloves and eye/face protection.
S45：In case of accident or if you feel unwell, seek medical advice immediately (show the lable where possible).
In case of an accident or feeling unwell, seek medical advice immediately (show the label if possible).
S53：Avoid exposure - obtain special instructions before use.
Avoid contact and obtain special instructions before use.
Risk terminology
R11：Highly flammable.
Highly flammable.
R36/37/38：Irritating to eyes, respiratory system and skin.
Irritating to eyes, respiratory system and skin.
R39/23/24/25：Toxic : danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed.
Toxic: danger of extremely serious irreversible effects through inhalation, contact with skin and if swallowed.
R40：Possible risks of irreversible effects.
There may be risk of irreversible effects.
R41：Risk of serious damage to eyes.
Risk of serious damage to eyes.
R45：May cause cancer.
May cause cancer.
R46：May cause heritable genetic damage.
It may cause irreversible genetic damage.
R48/20/22：Harmful : danger of serious damage to health by prolonged exposure through inhalation and if swallowed.
Harmful: danger of serious damage to health through long-term exposure through inhalation and ingestion.
R66：Repeated exposure may cause skin dryness or cracking.
