preparation of t-butyl chloride - university of illinois...

Preparation of t-butyl chloride(2-chloro-2-methylpropane)

CCH3

CH3CH3

OHHCl

CCH3

CH3CH3

Cl + H2O

t-butyl alcohol t-butyl chloride

(CH3)3COH + HCl

(CH3)3CCl + H2O

Reaction Mechanism?

(CH3)3COH + H-Cl

(CH3)3COH2 + Cl + -

Leaving Group

(CH3)3C-OH2 +

(CH3)3C + H2O

Cation

(CH3)3C + + Cl-

(CH3)3CCl

C CH3

CH3

CH3

tert-Butyl Cation

+sp2 flat

p

2

Transition State

δ δ

Substitution

Nucleophilic

1 bondat a time

Increasing Stability

Main Reaction

Side Reaction

CCH3

CH3CH3

OHHCl

CCH3

CH3CH3

Cl + H2O

t-butyl alcohol t-butyl chloride

CCH3

CH3CH3

OHHCl

+ H2O

t-butyl alcohol

CH2CCH3

CH3

isobutylene

CH2CCH3

CH3

C

CH3

CH3CH3

CCH3

CH3CH3

Cl

E1 N

ProcedureShake t-BuOH with concentrated HCl

Separate layers

Wash saturated aqueous NaCl

Wash saturated aqueous NaHCO3

Dry

Distill

t-BuCl

Shake t-BuOH with HCl

NaHCO3 + HCl

CO2 + H2O + NaCl

Wash to remove excess HCl

Distill product

Cool receiver

Clamp joints

Yield Calculations

A + B CMW 100 100 200

Use: 10 g A 20 g B

Limiting Reagent

Theoretical Yield

Experimental Yield

A + B CMW 100 100 200

Cpd Mass MW Moles

A 10 g 100 0.10

B 20 g 100 0.20

Theoretical yield:0.10 moles x 200 = 20 g

Experimental yield (%):100 x wt product / 20

LimitingReagent

CH3CH2CH2CH2OH n-butyl alcohol

HBr

CH3CH2CH2CH2Brn-butyl bromide

RCH2OH + H+ RCH2OH2+

C

R

HHOH2Br

δ− δ+

transition state

RCH2Br

Substitution

Nucleophilic

2 bonds ata time