Preparation Of Alkenes

Question 1

3 methods to prepare alkene?

Answer 1

1. Elimination
2. Dehydration of alcohols
3. Thermal or catalytic cracking

Question 2

Describe elimination

Answer 2

@elimination
(R): KOH in ethanol
(C): reflux

Halogenoalkane + KOH -> alkene + KX + H2O

*major and minor pdts

Question 3

Describe dehydration of alcohols

1. Industrial process
2. Lab process

Answer 3

1. Industrial

(R):Al2O3
(C): heat

Alcohols -> alkene + H2O

2. Lab

(R): conc. H2SO4 (catalyst&dehydrating agent)
(C): reflux

Alcohol -> alkene + H20

Question 4

Describe thermal or catalytic cracking

Answer 4

(C):

• high temp ~900degree
• high temp ~500degree with catalyst

**random process