Substitution Vs
Elimination Reaction

Contents

• Bimolecular reactions

• Nature of the substrate

• Temperature

• Nature of the reagents

• Solvents

Learning Objectives

At the end of this
lecture, student will be able to

• Compare elimination and substitution reactions

• Relate the structure of alkyl halide with mechanism

Elimination
vs Substitution Reaction

Bimolecular
reactions

– Nature of the substrate

– Temperature

– Nature of the reagents

– Solvents

Unimolecular
reactions

– Nature of the substrate

– Temperature

– Nature of the reagents

– Solvents

• Reactivity of alkyl
halides towards substitution and elimination

• Effects of reaction
variables on substitution and elimination reactions

Summary

• Elimination and substitution reactions involves attack by
nucleophilic reagent

• Attack at carbon causes substitution, attack at hydrogen
causes elimination

• Dehydration of alcohol involves heating alcohol with acid
catalyst

• Tertiary alcohols – easiest to dehydrate, primary alcohols
– hardest

• Major product is the more substituted alkene as given by
Saytzeff rule