Advices For Studying Organic Chemistry

hydrolysis is the Markovnikov addition of H– and –OH.

8.5 ADDITION OF WATER TO ALKENES:

ACID-CATALYZED HYDRATION

1. The acid-catalyzed addition of water to the double bond of an alkene is a method
   for the preparation of low molecular weight alcohols that has its greatest utility in

1) The acids most commonly used to catalyze the hydration of alkenes are dilute

solutions of sulfuric acid and phosphoric acid.

2) The addition of water to a double bond is usually regioselective and follows

Markovnikov’s rule.

large-scale industrial processes.

CC + HOH H^3 O

+

C

H OH

C

CCH 2

H C

H 3 C

+ HOH H^3 O

+^3

3

25 oC H^3 CC

CH

OH

CH 2 H

2-Methylpropene tert-Butyl alcohol

(isobutylene)

2

re ase of the hydration of

ethene.

. The acid-catalyzed hydration of alkenes follows Markovnikov’s rule ⇒ the
action does not yield 1° alcohols except in the special c

H 2 CCH 2 + HOH H^3 PO^4

300 oC

CH 3 CH 2 OH

3. The mechanism for the hydration of an alkene is the reverse of the mechanism for
   the dehydration of an alcohol.