CH3 C

H

H

Br CH3 C

H

H

OH-HO:

+ :Br -δ+ δ-

CH3 C

H

H

CNCH3 C

H

H

Br-NC:

+ :Br -δ+ δ-

CH2 C

H

H

BrCH3

CH2 C

H

H

NH2CH3

CH2 C

H

H

N+

CH3

H

H

H

3HN:

δ+ δ-

+ NH4Br

:OH-

C C

H

H

CH3

Br

H

H C C

H

CH3

H

H

+ Br - + H2O:NH3

:Br -

C C

H

H

H

H

C C

H

H

Br Br

H

H

C+

C

Br

H

HH

H

Br

Brδ+

δ-

:Br -

C+

C

H

CH3

HH

CH3

C C

H

CH3

HH

CH3

Br

C C CH3

HH

CH3

δ+

δ- :Br -

H

Br

H

OSO2OH

C C H

HH

CH3

δ+

δ-

-:OSO2OH

C+

C H

HH

CH3

H

C C H

HH

CH3

HOSO2OH

STEP ONE Initiation

Br2 2Br .Essential condition: UV light

CH3CH3 + Br. HBr + CH3CH2.

STEP TWO Propagation

CH3CH2. + Br2 CH3CH2Br + Br.

STEP THREE TerminationCH3CH2

. + Br. CH3CH2Br

CH3CH2. + CH3CH2

. CH3CH2CH2CH3

Mechanism Summary for AS AQA Chemistry

Nucleophilic Substitution of Halogenoalkaneswith aqueous hydroxide ions.

Nucleophilic Substitution of Halogenoalkaneswith cyanide ions.

Nucleophilic Substitution of Halogenoalkanes with ammoniaElimination of Halogenoalkanes with ethanolichydroxide ions

Electrophilic Addition of Alkenes with Bromine Electrophilic Addition of Alkenes with hydrogenbromide

Electrophilic Addition of Alkenes with sulphuric acid

Free Radical Substitution of Alkanes with Bromine

:CH3 C CH3

O H

H

CH3 C CH3

O+

H

H

H

C C+

CH3

H

H

H

H

H+H+

C C CH3

H

H

H

Acid catalysed elimination mechanism: alcoholsalkenes

The H+ comes from the conc H2SO4 or conc H3PO4

C C

HH

H H

C C+

H

H

H

H

H

OH

H

C C

O+

H

H

H

H

H

H

H

C C

O

H

H

H

H

H

HH+

H+

Acid catalysed addition mechanism for hydration of ethene

The H+ comes from the conc H3PO4

Alcoholic NH3heat under pressurenucleophilic substitution

1 H2SO42 H2O warmElectrophilicAddition

KOH aqueousheat under reflux

nucleophilic substitution

Br2, Cl2 UV lightFree radicalSubstitution

KOH aqueousheat under refluxnucleophilic substitution

amine

alkane

halogenoalkane

alkene

alcohol

ketonealdehyde

carboxylic acid

diol

dihalogenoalkane

conc H2SO4 orconc H3PO4Elimination

If primary alcohol or aldehydeK2Cr2O7/H+

heat under reflux+ excess oxidising agent

Oxidation

nitrile

KCN in alcoholheat under refluxnucleophilic substitution

poly(alkene)

high pressurecatalyst

AS Reactions- Summary