Chemistry
Session
Organic Compounds with Functional
Groups Containing Oxygen-II
Session Objectives
1. Preparation of methanol and its properties
2. Preparation of ethanol and its properties
3. Preparation of ethylene glycol and its properties
4. Preparation of glycerol and its properties
5. Preparation of phenol
Methanol
Preparation
1. From destructive distillation of wood
Pyroligneous acid obtained from destructive distillation of
wood consists of 5% methyl alcohol
2. By catalytic hydrogenation of carbon monoxide.
Cu  Zn  Cr O
2 3
CO  2H2 
 CH3OH
3. From natural gas
Cu / 250o C,100 atm
CH4  2O2  CH3OH
Properties of methanol
Colourless liquid.
Highly poisonous in nature; as little as 30 ml can cause death.
Uses
As a solvents in paints, varnishes.
Chiefly for making formaldehyde.
As an antifreeze for automobile radiators.
To denature ethyl alcohol.
20% mixture of methyl alcohol and gasoline makes a good motor fuel.
Ethanol
Fermentation of sugar
Invertase
C12H22O11  H2O 
 C6H12O6  C6H12O6
Glucos e
Fructose
Zymase
C6H12O6  2C2H5OH  2CO2
Fermentation stops when alcohol formed is more than 14
percent due to the acidic nature of the alcohol.
Synthesis of alcohol
H3PO4 / 300o C, 60 atm
C2H4  H2O  C2H5OH
Ethylene
Important reactions
Reaction with sulphuric acid:
(i) At room temperature
C2H5OH + H2SO4  C2H5OSO2OH + H2O
(ii) At 140oC
C2H5OH + H2SO4  C2H5OC2H5 + H2O
(iii) At 170oC
C2H5OH + H2SO4  C2H4 + H2O
Reaction with alumina:
Al2O3 , 350 C
C2H5OH 
CH2  CH2
Al O , 200 C
C2H5OH 
 C2H5OC2H5
2
3
Specific reactions
Reduction
P, 
C2H5OH  2HI 
 C2H6  I2  H2O
oxidation
Na2Cr2O7 /H
Na2Cr2O7 /H
C2H5OH  CH3CHO  CH3COOH
Cu, 300 C
C2H5OH 
 CH3CHO  H2
Formation of iodoform

C2H5OH  4I2  6KOH 
 CHI3  HCOOK  5KI
Uses of ethyl alcohol
Manufacturing of alcoholic beverages.
As an industrial solvent.
Manufacturing drugs, flavouring extracts, and perfumes.
As an antiseptic in hospitals.
In manufacturing of synthetic rubber.
Absolute alcohol
100% pure ethyl alcohol
Commercial alcohol is 95% ethyl alcohol.
Because at this composition water and alcohol formed azeotropic
mixture,it cannot separated by further distillation.
Method to obtain absolute alcohol
Laboratory method:
Quicklime is added to the commercial alcohol. The mixture is refluxed
for 8 hours. It is then distilled to give absolute ethyl alcohol.
CH3CH2OH + H2O + CaO  CH3CH2OH + Ca(OH)2.
Industrial method:
Commercial alcohol is extracted with benzene. Distillation
this gives absolute alcohol at 78oC.
Denatured alcohol
Mixture of commercial ethyl alcohol with small amount of very
poisonous substances.
Alcoholic beverages.
Heavy
excise
duty
Denatured
For industrial purposes, it is duty free.
Alcoholic beverages
Wine  12% ethyl alcohol.
Beers  4% ethyl alcohol.
Whiskey  40-50% ethyl alcohol.
Brandy  40-50% ethyl alcohol.
Content of ethyl alcohol in beverages is indicated by ‘Proof Spirit’
Proof is the double of volume of ethyl alcohol in beverages.
Preparation of ethylene glycol
1. By oxidation of ethylene with cold dilute potassium
permanganate solution.
CH2
CH2
+ H2O + O
4
CH2OH
CH2OH
2. By hydrolysis of 1,2-dibromoethane with aqueous sodium
carbonate solution.
CH2Br
CH2Br
CH2OH
+ Na2CO3 + H2O
CH2OH
Preparation of glycol
3. By hydrolysis of ethylene oxide with H2O at 200oC under
pressure or with dilute H2SO4 at 60oC.
CH2
CH2
O
+ H2O
H+
o
60 C
CH2OH
CH2OH
Properties of glycol
It’s a colourless viscous liquid, b.p 197oC.
It has a sweet taste.
It is hygroscopic.
Soluble in ethanol and water.
Toxic as methyl alcohol when taken orally.
Reactions with sodium
It shows all the reactions of –OH group. Due to two –OH group it
consumes more reactants. Sometimes more drastic conditions are
require to react with second –OH group of ethylene glycol.
For example
CH2OH
HCl
CH2OH
160 C CH OH
2
o
CH2Cl
HCl
CH2Cl
o
200 C CH Cl
2
It is used as coolent in automobiles and synhetic fibres like dacron,
polyester used for making wrinkle free clothes.
Oxidation of glycol
(i). Nitric acid yields a number of substances.
CH2OH
CH2OH
CH2OH
CH2OH
CHO
Glycolic
aldehyde
Ethylene
glycol
COOH
Glycolic
acid
CHO
CHO
Glyoxal
CHO
COOH
COOH
Glyoxalic
acid
COOH
Oxalic Acid
(ii) With acidic potassium permanganate or
potessium dichromate gives formic acid.
O
CH2OH KMnO
4
H
C
OH
+
H
CH2OH
(iii). Periodic Acid Cleavage of Glycols
H
H
H
C
C H
HIO
OH OH
R
H
H
C
C R
HIO
OH OH
R
R'
R'
C
C R
OH OH
HIO
2H
4
3
O
2R
4
C H + HIO
3
O
2R
4
C H + HIO
C R' + HIO
O
3
Dehydration of ethylene glycol
C
H
2
C
H
2
O
; 500oC
CH2
HO CH2
CH2
O
O
H2SO4;  CH2OH
H2SO4; 
CH2OH
CH2
CH2
Dioxane
 ;ZnCl2
CH3CHO
CH2
O
HO CH2
CH2
Diethylene
glycol
Propane-1,2,3-triol(Glycerol)
Preparation
1. From fats and oils: by product of soap industry.
CH2OOCR
CHOOCR
CH2OH
+ 3NaOH
CHOH
+ 3RCOONa
Soap
CH2OOCR
Fat or oil
CH2OH
Glycerol
This reaction is called saponification.
Properties
Colourless, odourless sweet tasting and syrup liquid,
b.p. 290oC.
It is nontoxic.
Soluble in water and ethanol.
It is hygroscopic, i,.e., absorbs moisture from air.
Reaction with nitric acid
Gives nitroglycerine; pale yellow oily liquid;
a powerful
explosive.
CH2ONO2
CH2OH
CHOH
CH2OH
+ 3HNO3
CHONO2
CH2ONO2
Reaction with hydrogen iodide
With small amount of HI
CH2OH
CHOH
CH2I
+3HI
CH2OH
-I2
CH2
CHI
CH
CH2I
CH2I
With large amount of hydrogen iodide.
CH2
CH
CH2I
CH3
HI
-I2
CH3
CHI
CH
CH2I
CH2
CH3
HI
CHI
CH3
Reaction with oxalic acid
At 110oC, gives glyverol monoformate.
O
CH2OH
CHOH
COOH
+
CH2O
C
H
o
110 C
CHOH
COOH
CH2OH
CH2OH
At 260oC, gives allyl alcohol.
CH2OH
CHOH
HOOC
+
CH2
OOC
o
110 C
CH
OOC
CH2
-CO2
CH
HOOC
CH2OH
CH2OH
CH2OH
Oxidation
Two primary alcohol groups in glycerol are capable of being oxidized
to the aldehydes and then the carboxyl group. The secondary
alcohol group can be oxidized to the carbonyl group.
Variety of oxidation products obtained depending on the nature of
the Oxidising agent.
C O 2H
a.
With dilute HNO3 gives glyceric acid and tartonic acid.
b.
With concentrated HNO3 gives mainly glyceric acid.
c.
With bismuth nitrate gives mainly mesoxalic acid.
d.
With bromine water, sodium hypobromite, or Fenton’s reagent
(FeSO4+H2O2), gives a mixture of glyceraldehyde and
dihydroxyacetone.
e.
With periodic acid gives fornaldehyde and formic acid.
C O
C O 2H
Dehydration
When heated alone or with KHSO4 two molecules of water eliminates.
CH2OH
KHSO4
CH2
CH2OH
CH
CH2OH
CHO
Phenol
Containing —OH group attached directly to an aromatic ring.
OH
O H
OH
CH3
Phenol
o-Cresol
O H
Q u in o l
Compounds which contain an —OH group in a side chain attached to
anb aromatic ring are not phenols. They are called aromatic alcohol.
For example
CH2OH
Benzyl alcohol
Preparation of phenol
From aryl sulphonic acids
Aryl sulphonic acid gives corresponding phenol on heating with
molten sodium hydroxide at 570-620 K.
SO3H
+ NaOH
SO3Na
ONa
H+
OH
Preparation of phenol
Chlorobenzene is hydrolysed by treating it with NaOH
at 623 K and 320 atm.
Cl
ONa
+ NaOH
623 K
320 atm
H+
OH
Preparation of phenol
From hydrolysis of diazonium salt
Diazonium salts are prepared by treating an aromatic primary
amine with nitrous acid (NaNO2 + HCl) at low temperature.
+
NH2
–
N2Cl
NaNO2 + HCl
OH
H2O
Benzene
diazonium
chloride
Phenol
Preparation methods
Synthesis from cumene
CH3
CH3
CH
CH3
O
2




O
OH
C
CH3
OH
H3O 
+
 

CH3
C
CH3
O
By decarboxylation of salicylic acid with soda lime
ONa
OH
COOH
+
CaO, 360 K
3NaOH
-Na2CO3, -2H2O
OH
HCl
-NaCl
Thank you