CH3
CH3
CH CH2OH
2-methyl-1-propanol
OH
CH3
CH CH2CH3
2-butanol
CH3
CH3
OH
C OH
CH3
2-methyl-2-propanol
Br
CH3
3-bromo-3-methylcyclohexanol
=>
If an alcohol is present, it takes naming/numbering priority over alkenes
This would be named prop-2-en-1-ol or 2-propen-1-ol.
The common name would be allyl alcohol.
This would be named 3-cyclohexen-1-ol or cyclohex-3-en-1-ol.
The numbering would prioritize the hydroxyl group
This would be named 3-phenylbutan-2-ol
or 3-phenyl-2-butanol.
Dihydric alcohol
Polyhydric alcohol
Methods of Preparation
Alcohols can be formed from many, many different sources.
More than 7 different functional groups can be converted to
an alcohol.
R
HC
Ketones
O
Aldehydes
C
R
Ethers
Alkenes
CH2
R
OR'
R'
O
Alkyl Halides
X
R
Epoxides
Alcohols
R
R
OH
Carboxylic Acids
OH
R
C
Acid chlorides
O
Cl
R
C
O
Esters
R
OR'
C
O
Methods of Preparation
Methods of Preparation
Methods of Preparation
Methods of Preparation
SYNTHESIS OF 1° ALCOHOLS
Grignard + formaldehyde yields a primary alcohol with one
additional carbon.
CH3
H3C C CH2
C
H
H
CH3
H
H
MgBr
C O
CH3
CH CH2
H
CH2
H
H
CH3
CH3
C O
CH CH2
H
CH2
C O H
H
HOH
MgBr
Methods of Preparation
SYNTHESIS OF 2º ALCOHOLS
Grignard + aldehyde yields a secondary alcohol.
CH3
H3C C CH2
C
H
H
CH3
H3C
H
MgBr
C O
CH3
CH CH2
CH3
CH2
H
H
CH3
CH3
C O
CH CH2
CH3
CH2
C O H
H
HOH
MgBr
Methods of Preparation
SYNTHESIS OF 3º ALCOHOLS
Grignard + ketone yields a tertiary alcohol.
CH3
H3C C CH2
C
H
H
CH3
H3C
H
MgBr
C O
CH3
CH CH2
CH3
CH2
H3C
CH3
CH3
CH3
C O
CH CH2
CH3
CH2
C O H
CH3
HOH
MgBr
Methods of Preparation
SODIUM BOROHYDRIDE
Hydride ion, H-, attacks the carbonyl
carbon, forming an alkoxide ion.
Then the alkoxide ion is protonated by
dilute acid.
Only reacts with carbonyl of aldehyde or
ketone, not with carbonyls of esters or
carboxylic acids.
O
C
H
H
H
C
H
O
+
H
H3O
O H
C
H
=>
Methods of Preparation
CATALYTIC HYDROGENATION
Add H2 with Raney nickel catalyst.
Also reduces any C=C bonds.
OH
O
NaBH4
OH
H2, Raney Ni
1o alcohol
2o alcohol
Reactions of alcohols
OXIDATION OF 1° ALCOHOLS
1° alcohol to aldehyde to carboxylic acid
Difficult to stop at aldehyde
Use pyridinium chlorochromate (PCC) to limit
the oxidation.
PCC can also be used to oxidize 2° alcohols to
ketones.
OH
CH3CH2CH2CH2
N H CrO3Cl
O
CH3CH2CH2CH
=>
Reactions of alcohols
OXIDATION OF 2° ALCOHOLS
2° alcohol becomes a ketone
Reagent is Na2Cr2O7/H2SO4
Active reagent probably H2CrO4
Color change: orange to greenish-blue
OH
CH3CHCH2CH3
Na2Cr2O7 / H2SO4
O
CH3CCH2CH3
=>
Reactions of alcohols
3° ALCOHOLS DON’T OXIDIZE
Cannot lose 2 H’s
Basis for chromic acid test
=>
Reactions of alcohols
REACTION WITH HCL
Chloride is a weaker nucleophile than
bromide.
Add ZnCl2, which bonds strongly with
–OH, to promote the reaction.
The chloride product is insoluble.
Lucas test: ZnCl2 in concentrated HCl:
1° alcohols react slowly or not at all.
2 alcohols react in 1-5 minutes.
3 alcohols react in less than 1 minute.
Reactions of alcohols
SN1 REACTION WITH THE LUCAS REAGENT
Secondary and tertiary alcohols react with the Lucas reagent (HCl and ZnCl2)
by the SN1 mechanism.
Reactions of alcohols
Ester: Sweet smelling
Reactions of alcohols
REACTION OF ALCOHOLS WITH A BASE
 Active metals such as Na, Li, K, Ca, etc. are very strong bases.
 They deprotonate alcohols liberating H2 gas
 Draw products and show mechanisms for the following.
CH3CH2O
+
H
Na
.
H3C
CH
1
+
/2 H2
sodium ethoxide
ethanol
O
CH3CH2O- Na+
H
+
H3C
CH
K
H3Cisopropyl alcohol
H3C
O- K+
+
1
/2 H2
potassium isopropoxide
Reactions of alcohols
SOLUBILITY AND BOILING POINTS OF ALCOHOLS
 Alcohols are the first organics we have studied that are polar.
 Alkanes, alkenes, alkynes and arenes are all hydrocarbons with
non polar bonds. Even alkyl halides are only weakly polar. These
compounds all exhibit characteristically low boiling points are are
insoluble in polar solvent like water.
HC and RX
n-pentane
carbon tetrachloride
n-butyl bromide
H2O Solubility
(g/100 mL, 25 C)
0.05
0.08
0.06
Alcohols/phenol
H2O Solubility
(g/100 mL, 20 C)
n-butyl alcohol
sec-butyl alcohol
isobutyl alcohol
tert-butyl alcohol
n-pentyl alcohol
n-hexyl alcohol
1-heptanol
phenol
1-octanol
1,4-butanediol
9
12
10
miscible
2.7
0.6
0.2
6.7
0.05
miscible
Reactions of alcohols