very
slow H^3 CC
CH 3
CH 2 +
H +
H
C CH 2 OH
CH 3
H 3 C HO
H
H
+
For all practiacl purp reaction does not tak
because it produces a 1° carbocation.
re
ned by the position of an equilibrium.
1) The dehydration of an alcohol is best carried out using a concentrated acid so
that the concentration of water is low.
i) The water can be removed as it is formed, and it helps to use a high
temperature.
2) The hydration of an alkene is best carried out using dilute acid so that the
concentration of water is high.
i
- rearranges to a more stable one if such a rearrangement is possible.
oses this e place
- The ultimate products for the hydration of alkenes or dehydration of alcohols a
gover
) It helps to use a lower temperature.
The reaction involves the formation of a carbocation in the first step ⇒ the
carbocation
H 3 CC
CH 3 OH
CH 3
CH CH 2 HH^2 SO 2 O^4 H 3 CC
CH 3
CH CH 3
CH 3
2,3-Dimethy
(major product)
3,3-Dimethyl-1
- Oxym on of H–
and –OH without
-butene l-2-butanol
ercuration-demercuration allows the Markovnikov additi
rearrangements.
- Hydroboration-oxidation permits the anti-Markovnikov and syn addition of H–
and –OH without rearrangements.
