Quick Revision: Alcohols, Phenols & Ethers | Chemistry Class 12 - NEET PDF Download

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ALCOHOLS
Molecules containing –OH group are termed as alcohols. Classification of alcohols they are classified
as primary, secondary or tertiary alcohol according to the carbon that is bonded with –OH.
Again when any molecule contain 1, 2 or 3 –OH groups then it is called mono, di or tri hydric alcohols
respectively. (as in case of alkyl halides)
OH
CH – CH
22
OH OH
CH – CH – CH
22
OH OH
CH – CH OH
32
Ethyl alcohol
(monohydric)
Ethylene glycol
(dihydric)
Glycerol
(trihydric)
GENERAL METHODS OF PREPARATION
1. From Alkenes :
(i) By Acid catalyzed hydrolysis :
CH – CH = CH + H O
2 3 2
CH – CH – CH
33
OH
HSO
24
(ii) Oxymercuration followed by demercuration :
CH – CH = CH + H O
2 3 2
Hg (OAc)
2
THF
CH – CH – CH
2 2
OH
CH – CH – CH
33
OH
NaBH
4
OH
–
Hg(OAc)
Overall result of above reaction is Markownikoff addition of water without rearrangement
(iii) Hydroboration followed by oxidation :
6CH – CH = CH
3 2
2(CH – CH – CH –) B
32 23
BH
26
HO/OH
22
 
6CH – CH – CH
3
 + 2H BO
22 33
OH
Overall result of above reaction is anti Markownikoff addition of water with no rearrangement.
(iv) Oxo process followed by hydrogenation :
CH – CH = CH + CO + H
32 2
[Co(CO) ]
42
high temperature
and high pressure
CH – CH – CH – C – H
32 2
H/Pd
2
CH – CH – CH – CH – OH
32 22
O
Product has one more carbon.