tert-Butyl chloride

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tert-Butyl chloride
Tert-butyl-chloride-2D-skeletal.pngTert-butyl-chloride-3D-balls.png
Identifiers
CAS number507-20-0 YesY
PubChem10486
ChemSpider10054 YesY
EC-number208-066-4
UN number1127
ChEMBLCHEMBL346997 YesY
RTECS numberTX5040000
Jmol-3D imagesImage 1
Properties
Molecular formulaC4H9Cl
Molar mass92.57 g/mol
AppearanceColorless liquid
Density0.84 g cm−3
Melting point−26 °C (−15 °F; 247 K)
Boiling point51 °C (124 °F; 324 K)
Solubility in waterSparingly sol in water, miscible with alcohol and ether
Vapor pressure34.9 kPa (20 °C)
Hazards
EU classificationFlammable (F)
R-phrasesR12, R36/37/38
S-phrasesS7, S9, S16, S29, S33
NFPA 704
Flash point−9 °C (open cup)
−23 °C (closed cup)
Related compounds
Related alkyl halidestert-Butyl bromide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references
 
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tert-Butyl chloride
Tert-butyl-chloride-2D-skeletal.pngTert-butyl-chloride-3D-balls.png
Identifiers
CAS number507-20-0 YesY
PubChem10486
ChemSpider10054 YesY
EC-number208-066-4
UN number1127
ChEMBLCHEMBL346997 YesY
RTECS numberTX5040000
Jmol-3D imagesImage 1
Properties
Molecular formulaC4H9Cl
Molar mass92.57 g/mol
AppearanceColorless liquid
Density0.84 g cm−3
Melting point−26 °C (−15 °F; 247 K)
Boiling point51 °C (124 °F; 324 K)
Solubility in waterSparingly sol in water, miscible with alcohol and ether
Vapor pressure34.9 kPa (20 °C)
Hazards
EU classificationFlammable (F)
R-phrasesR12, R36/37/38
S-phrasesS7, S9, S16, S29, S33
NFPA 704
Flash point−9 °C (open cup)
−23 °C (closed cup)
Related compounds
Related alkyl halidestert-Butyl bromide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

tert-Butyl chloride is a colorless, liquid organic compound at room temperature. It is sparingly soluble in water, with a tendency to undergo spontaneous solvolysis when dissolved into it. The compound is flammable and volatile, and its main use is as a starting molecule to carry out nucleophilic substitution reactions, to produce different substances, ranging from alcohols to alkoxide salts.

When tert-butyl chloride is dissolved in a polar and protic solvent, like water, it undergoes a solvolysis reaction. The chloride groups leaves, causing an heterolytic rupture of the compound, giving rise to a carbocation which eventually becomes a tertiary alcohol after a water molecule reacts with it, releasing hydrochloric acid as the final product. If a different, stronger nucleophilic agent is present at the moment of reaction, reaction product may not be an alcohol, but a tertiary carbon with the nucleophile as a substituent. Because of the steric hindrance of the tert-butyl group the solvolysis reaction follows the SN1 mechanism and not the SN2 mechanism.

Synthesis[edit]

tert-Butyl chloride can be synthesized in the laboratory by the SN1 reaction of tert-Butanol with concentrated hydrochloric acid, as shown below.

Step 1
Step 2
Step 3
1-HCl-protonates-tBuOH-2D-skeletal.png
2-water-leaves-protonated-tBuOH-2D-skeletal.png
3-chloride-attacks-tBu-cation-2D-skeletal.png
The acid protonates the alcohol, forming a good leaving group (water).
Water leaves the protonated t-BuOH, forming a relatively stable tertiary carbocation.
The chloride ion attacks the carbocation, forming t-BuCl.

The overall reaction, therefore, is:

0-SN1-tBuOH-to-tBuCl-2D-skeletal.png

Because tert-butanol is a tertiary alcohol, the relative stability of the tert-butyl carbocation in the Step 2 allows the SN1 mechanism to be followed, whereas a primary alcohol would follow an SN2 mechanism.

See also[edit]

External links[edit]