Mechanisms in Organic Chemistry Alkenes Electrophilic Addition HBr

Mechanisms in Organic Chemistry Alkenes Electrophilic Addition HBr, Br 2(aq) Free Radical Polymerisation Aldehydes or ketones Nucleophilic Addition Halogenoalkanes Arenes Alkanes Nucleophilic Substitution SN 1 SN 2 Electrophilic Substitution Free Radical Substitution

Electrophilic Addition 1 – Ethene + HBr H H C C H H Br d+ d H H _ H H H C C + : Br _ H H C C Br H H H home H

Electrophilic Addition 2 – Ethene + Br 2(hexane) H H C C H Br Br d+ d H H _ H H H C C + : Br _ H H C C Br Br H Br home H

Electrophilic Addition 3 – Ethene + Br 2(aq) H H C C H Br Br d+ d H H H _ H H H C C OH Br H C C + H HBr Br : OH 2 : Br _ home H

Nucleophilic Addition – Reaction of HCN with Carbonyls d _ Cd + O : OH H+ H 3 C C H : CN _ : O H 3 C _ C CN H home CN H

Nucleophilic Substitution – SN 1 Mechanism H 3 C C + CH 3 H 3 C - Br C + : OH- CH 3 C C CH 3 OH : Br- Rate = k[C 4 H 9 Br] home

Nucleophilic Substitution – SN 2 Mechanism H H H + C C H H _ Br : OH- H OH : Br- Rate = k[C 2 H 5 Br][: OH-] (NB Transition state) home

Electrophilic Substitution 1 – Nitration of benzene H 2 SO 4 + NO 2+ HNO 3 +NO 2 H NO 2 + HSO 4 - + H 2 O NO 2 + H+ home

Electrophilic Substitution 2 – Bromination of benzene Br 2 + Br+ Al. Cl 3 +Br H Br + Al. Br. Cl 3 - Br + HBr home Al. Cl 3

Electrophilic Substitution 3 – Alkylation of benzene CH 3 Cl + CH 3+ Al. Cl 3 +CH 3 H CH 3 + Al. Cl 4 - CH 3 + HCl home Al. Cl 3

Electrophilic Substitution 4 – Acylation of benzene CH 3 COCl + CH 3 CO+ Al. Cl 3 O +C O CH 3 H C + Al. Cl 4 O CH 3 C CH 3 + HCl home Al. Cl 3

Bromination of methylbenzene – ring substitution Br 2 + Br+ Al. Br 3 + CH 3 Br+ Al. Br 4 - CH 3 H Br Br + HBr home Al. Br 3

Free Radical Substitution 1 – Methane + Cl 2 Initiation Propagation u. v. light Cl Cl CH 4 + . Cl . CH Termination home . CH . 2 Cl. CH 3 + HCl 3 + Cl 2 CH 3 Cl + 3 . + CH C 2 H 6 3 + 3 . Cl CH 3 Cl . Cl

Free Radical Addition Polymerisation of Ethene heat Initiation R R C H H H C C H R H H C R H R H Propagation . 2 R C R H H H C C H H home