Trichloromethane
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Chemical formula | {{#Chem:CHCl3}} |
---|---|
OTP appearance | clear liquid |
Molar Mass(g/mol) | 119.38 |
Density(g/cc) | 1.489 |
Melting Point(°C) | −63.5 |
Boiling Point(°C) | 61.15 |
Solubility in water(g/L) | insoluble |
NFPA 704 |
Uses
Justification Questioned
Other
- Solvent
- Reagent
- Precursor to many other compounds including TFE
- General anesthetic
- Precursor to DCM ({{#Chem: CHCl3 + Zn + HCl = CH2Cl2 + ZnCl2 }}).
Natural occurrence
None.
Hazards
- CNS depressant
- Decomposes with oxygen into toxic byproducts
Production
Synthesis
From propanone
- Combine sodium hypochlorite and propanone producing a variety of compounds
- {{#Chem: 3 NaOCl + (CH3)2CO = CH3COONa + 2 NaOH + CHCl3 }}
- Pour off and discard the supernatant (water, sodium hydroxide, sodium acetate, sodium hypochlorite)
- The lower layer is mostly trichloromethane with some water.
- Chemically dry the trichloromethane over dried magnesium sulfate or calcium chloride
From methane
thermal conversion
- Mix methane and chlorine gasses
- Heat to temperatures yielding hydrochloric acid and a variety of chlorine-substituted methane compounds
- {{#Chem: 4CH4 + 10Cl2 { 400-500° C = } CH3Cl + CH2Cl2 + CHCl3 + CCl4 + 10HCl }}
ultraviolet conversion
Purification
Fractionally distill the product mixture
Compound | Boiling point (°C) |
---|---|
{{#Chem:CH3Cl}} | -23.8 |
{{#Chem:CH2Cl2}} | 39.6 |
{{#Chem:CHCl3}} | 61.15 |
{{#Chem:CCl4}} | 76.72 |
Rectification
Trichloromethane catalytically decomposes (in the presence of) oxygen into toxic byproducts:
- {{#Chem: 2 CHCl3 + O2 = 2 COCl2 + 2 HCl}}
This can be addressed as follows:
- Prepare a saturated solution of sodium carbonate or sodium bicarbonate
- Combine this with the trichloromethane
- {{#Chem: COCl2 + H2O = CO2 + HCl}}
- {{#Chem: 2HCl + Na2CO3 = 2NaCl + CO2 + H2O }}
- Agitate
- Let stand
- Pour off the supernatant
- Filter
- Discard the residue
- Chemically dry the filtrate yielding rectified trichloromethane
Storage
- Store with 1% by mass ethanol, removing any produced dichlorocarbonyl as diethyl carbonate