tert-Butyl chloride

tert-Butyl chloride
Names
IUPAC name
2-chloro-2-methylpropane
Other names
1,1-dimethylethyl chloride
1-chloro-1,1-dimethylethane
chlorotrimethylmethane
trimethylchloromethane
t-butyl chloride
Identifiers
507-20-0 YesY
ChEMBL ChEMBL346997 YesY
ChemSpider 10054 YesY
EC Number 208-066-4
Jmol interactive 3D Image
PubChem 10486
RTECS number TX5040000
UN number 1127
Properties
C4H9Cl
Molar mass 92.57 g/mol
Appearance Colorless liquid
Density 0.851 g/mL
Melting point −26 °C (−15 °F; 247 K)
Boiling point 51 °C (124 °F; 324 K)
Sparingly sol in water, miscible with alcohol and ether
Vapor pressure 34.9 kPa (20 °C)
Hazards
Flammable (F)
R-phrases R12, R36/37/38
S-phrases S7, S9, S16, S29, S33
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline) Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
3
2
0
Flash point −9 °C (16 °F; 264 K) (open cup)
−23 °C (closed cup)
540 °C (1,004 °F; 813 K)
Related compounds
tert-Butyl bromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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

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.

See also

External links

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