Electrophile - Electron deficient - Accept lone pair - Positive charge - Lewis Acid

C - Br

Reactivity for halogenoalkane Carbon bond to halogen F, CI, Br, I High electronegativity on halogen gp High reactivity due to polarity of C+- CI -

C - Br + -

electron

Electron deficient carbon

OH ..

- +

Nucleophilic Substitution rxn

CH3CH2CI + OH- CH3CH2OH + CI

-

H H

H - C C CI

H H

+ OH- + -

H H

H - C C OH + CI-

H H

H Br H

H - C C C H

H H H

CH3CHBrCH3 + OH- CH3CHOHCH3 + Br

-

+ OH-

H OH H

H - C C C H + Br-

H H H

+ -

Nucleophilic Substitution Electrophilic Addition

vs Reactivity of Alkene - High reactivity - Unstable bond bet C = C - High reactivity Weak pi bond overlap bet p orbital - Unsaturated hydrocarbon bond overlap

C = C Electron rich electron

- -

H +

C = C - -

E +

E+ Electron deficient Nu

-

-

Nucleophile Lone pair electron Donate electron pair - Lewis Base

H H

C = C

H H

CH2=CH2 + Br2 CH2BrCH2Br

+ Br Br - +

H H

H - C C H

Br Br

vs

CH2=CH2 + HCI CH3CH2CI

H H

C = C

H H

- + H CI

+

H H

H - C C H

H CI

Electrophilic Addition rxn

-

Electron rich region

Electrophilic Substitution rxn

C6H6 + Br2 C6H5Br + HBr

+ Br-Br +

+ NO2+

+

Electrophilic Substitution

vs

C = C Electron rich electron

- -

+

C = C - -

E +

E+ Electron deficient

E +

H H

C = C

H H

CH2=CH2 + Br2 CH2BrCH2Br

+ Br Br - +

H H

H - C C H

Br Br

vs

CH2=CH2 + HCI CH3CH2CI

H H

C = C

H H

- + H CI +

H H

H - C C H

H CI

Electrophilic Addition rxn

E

Electrophile - Electron deficient - Accept lone pair - Positive charge - Lewis Acid

+ + H E

+ H

Electron rich region

H Br

+ HBr

C6H6 + HNO3 C6H5NO2 + HCI

AICI3 dry ether

warm/conc H2SO4

H NO2

Reactivity of Alkene - High reactivity - Unstable bond bet C = C - High reactivity Weak pi bond overlap bet p orbital - Unsaturated hydrocarbon bond overlap

Reactivity of Benzene (Unreactive) - Delocalization of electron in ring - Stability due to delocalized electron - Substitution instead of Addition

C6H6 no reaction with brown Br2(I)

ethene decolourize brown Br2(I)

Benzene stable (unreactive) toward addition rxn

Electrophile - Electron deficient - Accept lone pair - Positive charge - Lewis Acid

H

Electrophilic Addition

Electrophile - Electron deficient - Accept lone pair - Positive charge - Lewis Acid

C - Br OH .. - +

Nucleophile Electrophile

+

C = C -

Nucleophile Lone pair electron Donate electron pair - Lewis Base

Organic Rxn

Addition rxn Substitution rxn

Nucleophilic Substitution

Free Radical Substitution

Electrophilic Substitution Electrophilic Addition rxn

Free radicle

CI CI

CI CI . .

:

Radical (unpair electron)

uv radiation

H H

C = C

H H

+ Br Br

H H

H - C C H

Br Br

+

-

H H

H - C C CI

H H

+ OH-

H H

H - C C OH + CI-

H H

- + H

E + + H

E +

H H

C = C

H H

H H

H - C C H

CI CI

H H

H - C C H

H CI

H H

H - C C H

H OH

Add HCI

CI2 / UV

H H

H - C C CI

H H

H H

H - C C OH + CI-

H H

H H

H - C C NH2 + CI-

H H

H H

H - C C CN + CI-

H H

NH3

OH-

CN-

H

H - C H

H

H

H - C CI + H

H

CI2 2 CI

CH3 + CI2 CH3CI + CI

CI + CH4 HCI + CH3

H

Electrophile - Electron deficient - Accept lone pair - Positive charge - Lewis Acid

C - Br OH .. - +

Nucleophile Electrophile

H +

C = C -

Nucleophile Lone pair electron Donate electron pair - Lewis Base

Free radicle

CI CI

CI CI . .

:

Radical (unpair electron)

uv radiation

H H

C = C

H H

H H

H - C C H

CI CI

H H

H - C C H

H CI

H H

H - C C H

H OH

Add HCI

CI2 / UV

H H

H - C C CI

H H

H H

H - C C OH + CI-

H H

H H

H - C C NH2 + CI-

H H

H H

H - C C CN + CI-

H H

NH3

OH-

CN-

H

H - C H

H

H

H - C CI + H

H

CI2 2 CI

CH3 + CI2 CH3CI + CI

CI + CH4 HCI + CH3

Alkene Addition rxn Halogenoalkane Substitution rxn Alkane - Radical substitution

H OH

H - C C H

H H

H O

H - C C H

H

H O

H - C C OH

H

H O H

H - C C C H

H H

H OH H

H - C C C H

H H H

H OH H

H - C C C H

H CH3 H

Alcohol Oxidation rxn

10 alcohol 20 alcohol 30 alcohol

carboxylic acid aldehyde ketone

no reaction

Electrophile - Electron deficient - Accept lone pair - Positive charge - Lewis Acid

Reactivity of Alkene - High reactivity - Unstable bond bet C = C - High reactivity Weak pi bond overlap bet p orbital - Unsaturated hydrocarbon bond overlap

C = C Electron rich electron

- - Br +

H H

C = C

H H

+ H Br - +

H H

H - C C H

+ H

Electrophilic Addition

Symmetrical Alkene

HBr polar

CH2=CH2 + HBr CH3CH2Br

: Br-

H H

H - C C H

H Br

CH2=CH2 + Br2 CH2BrCH2Br

Electrophilic addition to symmetrical alkene

H H

C = C

H H

+ Br Br + -

Br2 non polar : induced dipole due to C=C

H H

H - C C H

+ Br

: Br-

H H

H - C C H

Br Br

carbocation

carbocation

Heterolytic fission

Heterolytic fission

CH2=CH2 + Br2/H2O CH2BrCH2Br

H H

C = C

H H

+ Br Br

Heterolytic fission

+ -

H H

H - C C H

+ Br

: Br-

H H

H - C C H

Br Br

H H

H - C C H

+ Br

: OH- from

H2O

H H

H - C C H

Br OH

H H

C = C

H H

H H

CH3 C = C CH3

+ H Br

H H

H - C C H

H Br

+ H Br

H