Tert-Butyl chloride

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Tert-Butyl chloride
IUPAC name 2-chloro-2-methylpropane
Other names 1,1-dimethylethyl chloride
1-chloro-1,1-dimethylethane
2-chloroisobutane
2-methyl-2-chloropropane
chlorotrimethylmethane
trimethylchloromethane
t-butyl chloride
tert-butyl chloride
t-BuCl
UN 1127
Identifiers
CAS number [507-20-0]
PubChem 10486
EINECS number 208-066-4
RTECS number TX5040000
SMILES CC(C)(C)Cl
InChI 1/C4H9Cl/c1-4(2,3)5/h1-3H3
Properties
Molecular formula C4H9Cl
Molar mass 92.57 g/mol
Appearance Colorless liquid
Density 0.89 g cm−3
Melting point

−26 °C

Boiling point

51 °C

Vapor pressure 34.9 kPa (20 °C)
Hazards
EU classification Flammable (F)
NFPA 704
3
2
0
 
R-phrases R12, R36/37/38
S-phrases S7, S9, S16, S29, S33
Flash point −9 °C (open cup)
−23 °C (closed cup)
Autoignition
temperature
540 °C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and 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 water, a polar and protic solvent, the bulky chloride substituent is carried away by it, and isolated from the aliphatic chain, causing an heterolitic 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.

[edit] Synthesis

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
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:

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.

[edit] See also

[edit] External links