EXPERIMENT 1:DISTILLATIONCHEM 200 LABORATORY

DISTILLATION

• A process of converting a liquid to a vapor, condensing the vapor, and collecting the distillate to another container• Technique used to separate components in a liquid mixture

which different boiling points, or to separate a component that is not volatile.•Used in purifying or concentrating a liquid.

DALTON’S LAW OF PARTIAL PRESSURE

• The total vapor pressure of a mixture is equal to the sum of the partial pressures of its components.

RAOULT’S LAW

• For miscible liquids, the partial pressure of each component of a mixture at a given temperature is equal to the vapor pressure of the pure substance multiplied by its mole fraction in the solution.

4 DISTILLATION METHODS

1.Simple distillation2.Fractional distillation3.Vacuum distillation4.Steam distillation

SIMPLE DISTILLATION

•Used in the separation of a volatile liquid from a nonvolatile substance or a solid dissolved in the liquid.

FRACTIONAL DISTILLATION

• It is a series of distillation• The condensed vapors are past through a fractional column

where they undergo a series of vaporization and condensation•Used to separate miscible liquid mixtures that are volatile.• The efficiency of the fractionation column depends on its

length and packing and is expressed by the number of theoretical plates.

VACUUM DISTILLATION

•Distillation under reduced pressure and is used for distilling high-boiling point liquids or heat-sensitive compounds.

STEAM DISTILLATION

•Usually employed in the separation of an organic compound from a solid material with the use of water in the form of liquid or steam.• The organic compound must be immiscible in water.• It is based on the fact that immiscible mixtures boil at

temperatures lower than the boiling points of any components. Aromatic oils.

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 100

20

40

60

80

100

120

Series 1

Series 1

AZEOTROPES

• A liquid pair with a constant composition and boiling point that do not behave in accordance with Raoult’s Law• Minimum boiling point azeotropes – boil at a temperature lower than

the pure components• Maximum boing point azeotropes – boil at higher temperature than

either of the pure components.

Component A Components B

BP of Azeotrope

% (by weight) of A in Azeotrope

Minimum BP Azeotrope

Water, 100 Ethanol, 78.3 78.15 4.4

Maximum BP Azeotrope

Acetone, 56.4 Chloroform, 61.2

64.7 20