Transcript Do you know the topic today?

Do you know the topic today?
 What is the similarity among these drinks?
The above drinks contain …….
Introduction
 Alkanols
 Alcohols
 General Formula
CnH2n+1OH
or (R-OH)
 Functional Group - the hydroxyl group
R-OH
IUPAC System of Naming
 Choose the longest continuous carbon chain
containing the -OH group
 Final -e of the corresponding alkane name
is changed to -ol
IUPAC System of Naming
 Examples
CH3OH
CH3CH2OH
CH3CH2CH2OH
CH3CHOHCH3
methanol
ethanol
propan-1-ol
propan-2-ol
IUPAC System of Naming
 Name the compound
CH3
CH3 - C - CH3
OH
Answer : 2-methylpropan-2-ol
Structural Isomerism
 Examples : C3H7OH have 2 structural isomers
H H H
H H H
H-C-C-C-H
H-C-C-C-H
H H OH
H OH H
propan-1-ol
propan-2-ol
Structural Isomerism
 Quick check : Write down all the possible
structural isomers of C4H9OH
Structural Isomerism
CH3 - CH2 - CH2 - CH2
OH
CH3 - CH2 - CH2 - CH2
butan-1-ol
OH
butan-2-ol
CH3
CH3
CH3 - CH - CH2
CH3 - CH - CH2
OH
2-methylpropan-1-ol
OH
2-methylpropan-2-ol
Effects of Alcoholic Drinks


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
All are poisonous
Methanol (CH3OH) is toxic
All alcoholic drinks contain ethanol
Small amounts have relaxing effect, but
Large amounts is dangerous
 Taken in large amount has an immediate
bad effect of mental and physical
performance.
Effects of Alcoholic Drinks
 It affects the normal functioning of the
nervous system
 Excessive drinking of alcohol over a long
period of time, leads to damage of liver and
loss of memory
 People may become addicted to it
 Many health, family and social problems
are due to these alcoholics
Advice
SO DO NOT Drink
Manufacture of Ethanol
 Ethanol from ethene
 Ethanol from Fermentation
Ethanol from ethene
 Industrial ethanol is formed from ethene, a
petroleum product.
 The flow diagram for ethanol manufacture
by direct hydration of ethene
Ethene 
Condensor
Furnace
steam 
Reactor
ethanol +
water
 The chemical equation:
CH2=CH2 + H2O  C2H5OH
Ethanol from fermentation
Fermentation is the slow breakdown
of large molecules to smaller molecules
by micro-organism.
The sources are used
 Ethanol has been made by fermentation for
several thousand years.
 The raw material is some form of starch or
sugar such as :
wheat
rice
&
potatoes
grapes
apple
barley
-Different Source can make different Alcoholic drinks.
Starch/Sugar sources
Barley
Grape
Barley
Grape
Potatoes
Wheat
Alcoholic drink
Beer
Red/White wine
Whisky
Brandy
Vodka
Gin
Micro-organisms used –– Yeast





Zymase is an enzyme present in yeast.
Act as catalyst.
Conditions: room temperature and pressure.
Converts sugar to alkanol and CO2.
For example: Glucose C6H12O6 ,
 C6H12O6(aq)  CH2CH2OH
(l)
 CO2 (g)
Fermentation of glucose in laboratory
Solution of
glucose with
yeast
CO
?2
Lime
water
How to obtain a max. concentration
of ethanol from fermentation
 The yeast is killed when the proportion of
ethanol reaches about 15%.
 To obtain a further concentration of the
solution, fractional distillation is used.
 Max. concentration of the distillate is about
96%.
 Pure ethanol (absolute ethanol) is obtained
by using CaO (drying agent) to removed the
traces of the water.
Uses of Alkanol
1.
Physical Uses
•
•
2.
Solvents
Beverage
Chemical Uses
•
•
•
Fuel
Vinegar Synthesis
Ester Synthesis
1.
Physical Uses
A. Used as Solvent
Because Ethanol (CH3CH2OH)contains :
A.

Polar Group
Water Soluble
B.
Non-Polar Group

Oil Soluble
OH
CH3CH2
Hence, Ethanol is Soluble in
Both water and Oil
1.
Physical Uses
B. Used as Bervage
Because Ethanol (CH3CH2OH)contains :
Ethanol is used as bervage because
of its


GOOD TASTE
PROVIDE A RELEX SENSE
Hence, ethanol is used as
Bervage
2.
Chemical Uses
A. Used as Fuel
Because burning of Ethanol (CH3CH2OH)is
highly exothermic
CH3CH2OH + O2
CO2 + H2O
As much heat is given out from the above
reaction, ethanol can be burnt as fuel
2.
Chemical Uses
C. Used in preparation Ester
Because Ethanol (CH3CH2OH) react with
Ethanoic Acid to form Ester
O
CH3CH2OH + CH3C
OH
O
CH3C
OCH2CH3
The Ester formed can be used as a food
favoring .
2.
Chemical Uses
C. Used in synthesis of Vinegar
Because Ethanol (CH3CH2OH) react with
Oxidizing agent to form Ethanoic acid
[O]
CH3CH2OH
O
CH3C
The Ethanoic acid formed is used as a
main component in Vinegar.
OH
Revision
Introducing Alkanols
 The general formula: CnH2n+1OH or ROH
 The molecule consist of a functional group the _______ group (-OH) joined to an ____
group (R-) .
Revision
Introducing Alkanols
 The general formula: CnH2n+1OH or ROH
 The molecule consist of a functional group the hydroxyl group (-OH) joined to an alky
group (R-) .
Revision
The general formula of alkanol is
A
A.
CnH2nOH
B.
B
CnH2n+2OH
C
C.
CnH2n+1OH
D.
D
CnH2n-1OH
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2. Ethanol can be formed by two methods. They are
Hydration of
ethene
?
Equation:
CH2=CH2 + H2O 
C2H5OH
?
Fermentation
Equation:
C6H12O6(aq)
CH2CH2OH (l)  CO2 (g)
The FIVE uses of Ethanol
1.
Used as Solvent
2.
Used as Bervage
3.
Used as Fuel
4.
Used in preparation Ester
5.
Used in synthesis of Vinegar