UNIVERSITY OF NAIROBI'

COLLEGE OF BIOLOGICAL AND PHYSICAL SCIENCES

DEPARTMENT OF CHEMISTRY

FACULTY OF SCIENCE

AND

FACUL TY OF EXTERNAL STUDIES

COURSE TITLE: ORGANIC CHEMISTRY 2

COURSE CODE: SCH 202

Written by:

Dr. Amir Okeyo Yusuf,

Department of Chemistry,

University of Nairobi.

Reviewed by:

Prof. Peter Machacha Gitu,

Department of Chemistry,

. University of Nairobi

Edited by:

1 hJ 1.;1'0

TABLE OF CONTENTS

UNIT INTRODUCTION ~:~ :'.:.~.~~.7:.~.c:.~.:.':.~.~":..~.~.~.:.~~.~ ..:": viiLECTURE 1: ALKENES : 11.0 INTRODUCTION 11.1 INDUSTRIAL PREPARATIONS OF ALKENES 2

1.1.1 What is thermal cracking? 31.2 LABORATORY PREPARATION OF ALKENES ::~.~..:::7: :.. ~..~ 4

. 'lV II .6 '.L..1.3 ELECTRONIC STRUCTURE OF ALKENES ,....................................................... .. 4

1.3.1 Hybridization 51.4 NOMENCLATURE OF ALKENES : 6

A~T~~ii~e~.;~~.~~~~~~:::::::::::::::::::~:::::::::::::~~.:.:~:?~::~::::~:~.~~.:~:~~:~::~:~!.~::~:~:~:~~::::::::::::::::::::::::::::::::::~1.5 WHAT ARE ISOMERS? 10

I .5.1 cis-trans isomerism .:.~..r~.:.~~:~.f.lT.X\..~;:.C ~~!::.L 101.5.1.1 cis-isomer 101.5.1.2 trans-,;;omer 11

ACTIVITY 1.2 12. 1.6 Z, E DESIGNATION :.~~..::~.:.~..~~ 12

~.:~:~~~~~:~~:~:~~:::::::::::::::::::::::::::::::::::::~~:~:~:~~:~:~~::~:.:~:~~.:::::~~~::.. :::::::::::::::.. :::::::::::...:.: ::::::!;1.7

1.6.3~~~~ ~*~BiLiTY·::::::::::::::::::::::~~:-:?:~::::~:~::~:~:~::~~:::::::::::::::::::::::::::::::::::::::::::::::::::::::!:

1.8 WHAT IS SUBSTITUTION? -:.· 17UMMARY 18

LECTURE 2: REACTIONS OF ALKENES 202.0 II\TTRODUCTION 202.1 ADDITION OF HX TO ALKENES .........•.::..~.!/.:~.:·.·.:: 212.2 CARBOCATION STABILITY ~ ::: 222.3 MARKOVNIKOV'S ADDITION (1833-1904) ~..: ': ..~ 23ACTIVITY 2.1 ~ :,.;·.:·.~:;·..0 242.4 ADDITION OF HALOGENS · 242.5 HALOHYDRIN FORMATION ~ f ..,.:~.!.-.~'; ' L 252.6 HYDRATION TO ALCOHOLS 26

2.6.1 Reaction with acidified water 262.6.2 Oxymercuration 272.6.3 Hydroboration : · 28

ACTIVITY 2.2 : 292.7 RADICAL ADDITION OF HBr : ~ 292.8 HYDROGENATION 302.9 OXIDATIVE CLEAVAGE 31

2.9.1 Ozone cleavage 312.9.2 Potassium permanganate neutral or acidic 32

ACTIVITY :2.3 :!~.~~:.~ 332.10 HYDROXYLATION 332.11 CYCLOADDITION : 34

2.11.1 What is a carbene? 34ACTIVITY 2.4 : 35

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