1. Extractions
Mixture of benzoic acid, anthracene, and p-nitroaniline

3. Density of CH2Cl2 is 1.33 g/mL H2O CH2Cl2
Mixture of methylene chloride and water
Density of CH2Cl2 is 1.33 g/mL
H2O
CH2Cl2

4. If we dissolve NaCl in this mixture which phase has the highest salt concentration?
Salts concentrate in the water layer

5. If we dissolve benzoic acid in this mixture in which phase would it concentrate?
Salts
Neutral organic compounds concentrate in the organic phase

6. Water CH2Cl2 Salts in water phase
Neutral organic compounds in the organic phase
CH2Cl2

7. Treatment of benzoic acid with sodium hydroxide converts it into the salt, sodium benzoate.

10. Use separatory funnel for separations.

11. Shake to be sure phases equilibrate
Hold stopper and stopcock

12. Vent frequently

13. benzoic Acid p-nitroaniline anthracene CH2Cl2 Benzoic acid Anthracene

14. benzoic Acid
anthracene
CH2Cl2
NaOH
anthracene

15. HCl Dry filter evaporate weigh Filter wash dry weigh
NaOH
Dry filter evaporate
weigh
Filter wash dry weigh
Filter wash dry weigh

16. Addition of acid to the sodium benzoate solution causes benzoic acid to precipitate.

17. The benzoic acid is filtered, washed, and dried.

18. Weigh the benzoic acid and measure its melting point.

19. Cool to complete precipitation

20. Dry the methylene chloride solution of anthracene with a small amount of sodium sulfate.

21. Remove the drying agent by filtration through a fluted filter paper.

22. Evaporate the methylene chloride on a steam bath.
Use an inverted funnel connected to the vacuum line to collect the vapor.

23. Weigh your products and measure their melting points.
Put your samples in labeled vials and give them to your TA.

24. Partition Coefficients
10 g t-butyl alcohol
100 mL ether
100 mL water

25. x g / 200 mL 2.2 = ( 10 - x)g / 100 mL x = 8.1 grams
10 grams t-butyl alcohol
x g /
200 mL
2.2 =
( 10 - x)g /
100 mL
x = 8.1 grams

26. Which is better?
Extract once with 200 mL or twice with 100 mL?

27. If K = 1.0, a = 10 grams, S2 = 100 mL
Extract once with 200 mL yields 6.7 grams
Extract once with 100 mL yields 5.0 grams
Second extraction with 100 mL yields
2.5 grams
Total 2 extractions with 100 mL = 7.5 grams

28. Grams extracted vs. number of extractions for K = 1, 2 and 4