1. Intensive General Chemistry
Chemical separations I
Isabelle Vu Trieu

2. What is a distillation?
This a separation technique for purifying a liquid.
In this process, the liquid is heated to the boiling point and vaporized.
That vapor is then cooled and recondensed in the liquid form

3. Origin of distillation

4. Partition Partition constant: K = aA(phase 2)/ aA(phase 1) Phase 1 A

5. Ideal solutions
Solutions are ideal when the intermolecular interactions among species are identical
An ideal solution obeys Raoult’s law
PA = XA PAo

6. Raoult’s Law applied to mixtures
Relative volatility
 or RV

9. Relative Volatility  or RV

10. Phase diagram

11. In the distillation process, the vapors get enriched in the more volatile component

12. In the distillation process, the vapors get enriched in the more volatile component

13. Fractional distillation: numerous evaporation-distillation stages

14. Distillation columns

15. Distillation set-up

16. Introduction to chromatography
Chromatography is a separation technique based on partition between a mobile phase and a stationary phase.
Invented by a botanist (M.Tswett) at the beginning of the 20th century
From greek chroma:”color” and graphein:”write”

17. Introduction to chromatography
Phase 1
Phase 2 A
Mobile
phase
Stationary
phase
Partition constant: K = aA(stationary)/ aA(mobile)

18. Column Elution

19. Column Elution

20. Thin Layer Chromatography (TLC)

21. Pre-lab questions
Find out the flash point and the auto-ignition temperature of cyclohexane and toluene.
What is the meaning of these temperatures?
In the distillation part, what is the role of the stainless steel sponge?