- Distillation is a process that separates mixtures based on differences in boiling points. It involves heating a liquid mixture to form vapors, condensing the vapors back to liquid, and collecting the purified liquid fractions. - There are several types of distillation including simple, steam, fractional, and vacuum distillation which vary based on conditions and mixtures separated. - A laboratory experiment demonstrates simple distillation to separate ethanol and water using common distillation equipment like a round bottom flask, condenser, and receiver flask. The mixture is heated to form vapors that condense and drip into the collection flask.

1. Distillation

2. Index
1)Main Concept.
2)Raoul’s Law and Dalton’s Law.
3)Types of Distillation.
4)Laboratory Experiment.

3. Main Concept
• Distillation is a widely used method for separating
mixtures based on differences in the conditions
required to change the phase of components of
the mixture.
• To separate a mixture of
liquids, the liquid can be heated to force
components, which have different boiling points,
into the gas phase.

4. • The gas is then condensed back into liquid
form and collected.
• Repeating the process on the collected liquid
to improve the purity of the product is called
double distillation.
• Although the term is most commonly applied
to liquids, the reverse process can be used to
separate gases by liquefying components
using changes in temperature and/or
pressure.

5. Reboiler
Residue
Condenser
Distillate
Reflux
Feed

6. Raoul’s Law and Dalton’s Law
• For a mixture of liquids, the distillation process
is dependent on Dalton’s law and Raoult’s law.
• As per Raoult’s law, the partial pressure of a
single liquid component in an ideal liquid
mixture equals the product of the vapor
pressure of the pure component and its mole
fraction.

8. • According to Dalton’s law of partial pressures,
the total pressure exerted by a mixture of
gases is equal to the sum of the partial
pressures of all the constituent gases.

9. Types of
Distillation
Fractional
Simple Steam Vacuum

10. Simple Distillation
•Simple distillation involves heating the liquid
mixture to the boiling point and immediately
condensing the resulting vapors.
•Simple distillation is only effective for mixtures
wherein the boiling points of the liquids are
considerably different (a minimum difference of
25oC), and for mixtures having nonvolatile
impurities.

11. •The purity of the distillate (the purified liquid) is
governed by Raoult’s law.
•Simple distillation is used in a variety of in the
production of alcoholic beverages. Simple
distillation is also used in desalinization
processes, which create freshwater from
saltwater.

13. Steam Distillation
• Steam distillation is often used to
separate heat-sensitive components in a
mixture.
• This is done by passing steam through
the mixture (which is slightly heated) to
vaporize some of it.
• The process establishes a high heat-
transfer rate without the need for high
temperatures.

14. • The resulting vapor is condensed to afford the
required distillate.
• Steam Distillation is only effective for
substance that is immiscible with water, steam
volatile, and have a vapor pressure in boiling
water that is of the order of 1 kPa (0.01) atm.
• Steam distillation is used in perfume and
cologne production, as well as the production
of some cooking
materials.

16. Fractional Distillation
• Fractional distillation is often used to
separate mixtures of liquids that have
similar boiling points.
• It involves several vaporization-
condensation steps (which takes place in a
fractioning column).
• When heated, the liquid mixture is
converted into vapors that rise into the
fractioning column.

17. • The vapors now cool and condense on the
walls of the condenser.
• The hot vapors emanating from the distilling
flask now heat the condensed vapor, creating
new vapors.
• Many such vaporization-condensation cycles
take place and the purity of the distillate
improves with every cycle.
• Fractional distillation is only effective when
liquid to be mixed properly, and the boiling
point difference to be10°.

18. • Fractional distillation is used in:
a) the purification of water as well as
separating acetone and water.
b) oil refineries and chemical plants industries
mainly for purification and separation of
many organic compounds.
c) the separation of (liquefied) air.
Components like
liquid nitrogen and oxygen as well as
concentrated argon are obtained.
d) the production of high-purity silicon from
chlorosilanes. The
silicon is widely used in semiconductors.

19. Fractional
Distillation

20. Vacuum Distillation
• Vacuum distillation is ideal for separating
mixtures of liquids with very high boiling
points.
• In order to boil these compounds, heating
to high temperatures is an inefficient
method. Therefore, the pressure of the
surroundings is lowered instead.

21. • The lowering of the pressure enables the
component to boil at lower temperatures.
Once the vapor pressure of the component
is equal to the surrounding pressure, it is
converted into a vapor.
• These vapors are then condensed and
collected as the distillate. The vacuum
distillation method is also used to obtain
high-purity samples of compounds that
decompose at high temperatures.

22. • Vacuum distillation is only effective when
liquid boil at its higher temperature. There
should also be possibility of decomposing
before attaining of boiling point.
• Vacuum distillation is used in in petroleum
refining to distillate crude oil. It is also used in
food industry; the vacuum required in the
food is applied in the transport, processing,
filling and packaging of foodstuffs, in cleaning
operations and in the creation of appropriate
hygienic conditions.

23. Vacuum
Distillation

24. Laboratory Experiment
A simple distillation is used to separate ethanol
from water.
Equipment:
1. round bottom flask
2. three-way connecter
3. thermometer adapter and thermometer
4. heating mantle
5. condenser
6. receiver flask
7. tubes

25. Procedure
1. Check the calibration of the thermometer that
is to be used. This can be accomplished by
placing the thermometer in an ice bath of
distilled water. After the thermometer has been
allowed to reach thermal equilibrium, place it in
a beaker of boiling distilled water and again
allow it to reach thermal equilibrium. If the
temperatures measured deviate from the
expected values by more than two degrees,
obtain a new thermometer and check its
calibration.

26. 2. Fill the distillation flask. The flask should be no
more than two thirds full because there needs to
be sufficient clearance above the surface of the
liquid so that when boiling commences the liquid is
not propelled into the condenser, compromising
the purity of the distillate. Boiling chips should be
placed in the distillation flask for two reasons: they
will prevent superheating of the liquid being
distilled and they will cause a more controlled boil,
eliminating the possibility that the liquid in the
distillation flask will bump into the condenser.

27. The thermometer is inserted in the distillation flask
through a hole in the cork stopper.
The arm of the flask is inserted through a hole in the
stopper of the condenser. Make sure these stoppers are
airtight, or the vapor will escape.

28. 3. Heat the distillation flask slowly until the liquid
begins to boil. Vapors will begin to rise through the
neck of the distillation flask. As the vapors pass
through the condenser, they will condense and
drip into the collection receiver. An appropriate rate
of distillation is approximately 20 drops per
minute. Distillation must occur slowly enough that
all the vapors condense to liquid in the
condenser. Many organic compounds are
flammable and if vapors pass through the
condenser without condensing, they may ignite as
they come in contact with the heat source.

29. The distillation flask being
heated in a heating mantle.
The collection receiver
The vapors condense and
drip from the condenser
into the flask.

30. 4. As the distillate begins to drop from the condenser, the
temperature observed on the
thermometer should be changing steadily. When the
temperature stabilizes, stop the experiment.
5. Remove the heat source from the distillation flask before all
of the liquid is vaporized. If all of the
liquid is distilled away, there is a danger that peroxides, which
can ignite or explode, may be
present in the residue left behind. Also, when all of the liquid
has evaporated, the temperature of
the glass of the filtration flask will rise very rapidly, possibly
igniting whatever vapors may still be
present in the distillation flask.