HYDROXY COMPDS
Class
Homologous series :
10 :
General formula :
20 :
f(x) group
: name :
strc :
30 :
Nomenclature
Aliphatic
alcohols
Phenols
v) CH2(OH)CH2OH
i) 2,4-dinitropenol
i) CH3CH2OH
=
=
=
ii) 2-chloro-5-ethylphenol
vi) 1,4-cyclohexanediol
ii) 1-butanol
=
Aromatic
alcohols
=
=
* -OH group is attcd to the
iii) 4-methylcyclohexanol
side chain of
=
i) CH2 OH
ii) CH3CHCH2OH
=
iv) CH3CH(Br)CH2OH
=
=
1
Isomerism
Physical Props
Solubility
Structural
- ROH @ ROR
CnH2n+2O
- Chain
- Positional
Optical
-OH f(x) group
BP
forms
* Branched isomers have
BP than unbranched isomers.
Reason :
total surface area
intermolecular
* Chiral carbon
forces.
Alcohol >
compare to alkanes,
alkene, haloalkanes
of similar Mr.
Polyhydric alcohols
* Rotate plane
polarised light
with water.
* Polyhydric alcohols of comparable Mr to
monohydric alcohols
BP due to
intermolecular hydrogen bonding.
than monohydric
alcohols of
comparable sizes.
with the increase
hydrophobic size of
the hydro-carbon.
2
CHEMICAL PROPS
RO-H fission
i) Na metal
2RO-H + 2Na
2RONa + H2
eg : CH3CH2CH2OH + Na
:
O OH +
+
ii) Esterification
R - C - OH + H - OR’
O
carb. acid
alcohol
O
eg :
+
O COH +
HO
conc
H2SO4
R - C - OR’ + H2O
O
alkyl alkanoate
(ester)
+
CH3CH2COOH + CH3OH
+
O
+
COOCH3 + H2O
O
CH3 CH2 C-O-
+
+ H2O
3
RO-H fission
iii) Acylation, R-C-Cl + H-OR’
R-C-OR’ + HCl
O
O
eg : CH3CH2C Cl + CH3 CH2 OH
O
O
+
CH3
CCl + CH3CHOH
+
OH
O
+
+ H2O
NaOH
O
CH3COCl
C-Cl
O
iv) Oxidation
H
a) R-COH
H
KMnO4/ H+
RCOOH
KMnO4/ OH-,
RCOONa
10
alcohols
20
alcohols
30
alcohols
+ H2O
H+
+
2H2O
carboxylic acid / aldehyde
4
Oxidation
eg :
CH3CH2CH2OH
+
CH3CHCH2CH3
+
OH
CH3
CH3CH2CCH3
OH
+
b) Catalytic oxidation
10 alcohol
20 alcohol
30 alcohol
Cu
aldehyde + H2
Cu
ketone + H2
Cu
resist
eg : CH3CH2OH
Cu
CH3CHCH3
Cu
+
+
OH
CH3C(CH3) CH3
Cu
+
OH
5
CHEMICAL PROPS
R-OH fission
Type of rx :
i) Halogenation
a) R-OH + H-X
R-X + H2O
ZnCl2
eg : CH3CH2CH2OH + HCl
CH3CHCH3
+
conc H2SO4/ NaBr
+
CH3C(CH3)2 + HCl
+
OH
Reactivity of rx : 30 al-ol > 20 al-ol > 10 al-ol > CH3OH
H
H3C <
+
R-C+
H
b) 3R-OH + PX3
H
<
R
< R-C+
R
R
R-C+
3R-X + H3PO3
eg : CH3CH2OH + PCl3
+ H3PO3
CH3CHCH3 +
OH
+
CH3C(CH3)2 + PI3
+ H3PO3
OH
6
R-OH fission
* confirmatory test :_______________
_______________________________
White fume
c) rx PCl5 / SOCl2
R-OH + PCl5
R-Cl + POCl3 + HCl
R-OH + SOCl2
R-Cl + SO2 + HCl
eg : CH3CH2CH2OH + PCl5
+
+
+
CH3CHCH3 + SOCl2
+
OH
ii) Dehydration
a) Formation of alkene
H
-C-C-
conc
H2SO4
C=C
+ H2O
OH
eg : CH3CH2CH2OH
conc
H2SO4
+ H2O
180 0C
CH3CHCH2CH3
OH
+
major
minor
* Saytzeff Rule
b) formation of ether
eg : CH3CHCH3
145 0C
_____________
OH
7
+
H2O
Confirmatory Test
Al-ol
Distinguish b/w
10, 20 & 30
Triodomethane
Test
i) Rgt : KMnO4 (aq)/ H+
Determine al-ol
with structure :
Cond : Heat
Obsvt : 10 :
OH
20 :
CH3
30 :
C
H
ii) Rgt : K2Cr2O7 (aq)/ H+
Cond : Heat
Rgt : I2 in NaOH (aq)
Obsvt : 10 :
Cond : heat/ reflux
Obsrt : +ve :
20 :
30 :
iii) Rgt : Conc HCl + ZnCl2
Eq=n :
(Lucas Reagent)
CH3CH-R + 4I2 + 6NaOH
Cond : rt
Obsvt :
10
OH
:
CHI3 + RCOONa +
20 :
5NaI + 5H2O
30 :
8
CHEMICAL PROPS OF
PHENOLS
E+ Substitution
1) + NaOH
3) + Acyl chloride
OH
O + NaOH
2) + Na
+
OH
+
+ Na
OH
O
+
O
CH3CHCCl
+
O
CH3CH2CCl +
+
OH
i) Nitration :
OH
2
+ HNO3
Conc
H2SO4
rt
ii) Alkylation :
OH
+
HNO3
AlCl3
rt
+
+
+
+
Test for phenol
i) + Bromine water
OH
+
3Br2
ii) with FeCl3 solution :
+
rt
O
+
FeCl3
obsrt :
OH
9
to : manufacture
CUMENE PROCESS
Step 1 :
Step 2 :
+
CH3CH=CH2
Cumene
O2,
Cumene
120 0C
dil H2SO4
+
H2/ Ni Manufacture of
cyclohexanol
[
(2n-1) H2O
+
C-(CH2)4-C-N-(CH2)6-N
O
OH
]
H
conc HNO3,
n
heat
Nylon 6,6
condensation
1,6 - hexanedioic acid
2NH3
1,6-hexanadiamine
H2/ Ni
Heat, -2H2O
Heat,
P4O10
10
Lab & Industrial Prep
of Alcohol
In the lab
Fermentation
process
zymase
Carbohydrates
name : _____________
+
Industrially
_____
+
___
i) Strength of
O-H bond
depends
R-OH + H2O
Acidity Strength
CH2=CH2
R-O- + H3O+
ii) Stability of
anion formed
OH > H2O > CH3CH2OH
weaker bond
degree of dissociation,
stable the anion
Ka values
pKa
acid
ii) Resonance effect
i) Inductive effect
-ve charge on
= electron
O-H bonds
delocalised into
stabilises the anion.
tendency to attract
R = electron
O - H bonds
alkyl group
e- density on oxygen atom , become
reactive to attract __________
11