LAB 4

It is a separation technique that separates liquids
upon heating on the basis of their boiling points.

Process for separating components of a
mixture, in which the components are evaporated
and the vapors condensed

Used to purify organic compound

The most volatile substance is vaporized first and
removed from the mixture first.

Three general steps of Distillation:

In general, the greater the difference
between the boiling points of the
component molecules in a solution, the
better the separation effect will be;
conversely if the difference between
boiling points is very small, this method
cannot be used.

Vapor enters a condenser, cools, and is collected

Used when components have greatly
different boiling points or to separate
volatile from non-volatile components

Used when the boiling points of the components of a
mixture are close to each other

Involves use of a fractionating column above the
distillation flask

Column offers more surface area, allowing for more
efficient condensation of vapor and an improved
separation

Used to separate heat-sensitive components

Water is added to the distilling flask.

This lowers the boiling point of the components so
they may be separated at a temperature below their
decomposition point

Used to separate components that have high boiling points

Lowering the pressure lowers boiling points

The preferred method for solvent removal in
the laboratory is by use of a rotary
evaporator (also known as a "rotovap")

The reduced pressure in the apparatus
causes the solvent to boil at a lower
temperature than normal.

Used in chemistry to separate and purify liquids

simple vacuum distillation to remove solvent from a sample

Application of Distillation

One of the oldest methods of desalinating water

(C4 to C12 ) 40oC to about 200oC

(C12 to C16 ) 200oC to about 250oC

¤ Gasoline (C4 to C12 ) 40oC to about 200oC
¤ Kerosene/jet fuel (C12 to C16 ) 200oC to about 250oC