1. Lecture 3 Chapter 5: Extraction Lecture Problem 1 Due Thursday
This week in lab:
Ch 4: Recrystallization & Melting Point
Procedures 1 & 2
Ch 4 PreLab Due
Quiz 1
Next week in lab:
Ch 4: Procedures 3 & 5
Ch 5: Extraction, Procedure 1
Ch 5 PreLab Due & Quiz 2

2. Chapter 5: Extraction Extraction
“Pulling out” a component from a mixture
Used to isolated specific compounds
Used to purify a compound
Types: Liquid/liquid extraction, solid/liquid extraction
Two day lab:
Procedure 1: Separation of an unknown three-component mixture
Procedure 2: Extraction of caffeine from tea or coffee

3. Chapter 5: Procedure 1
Separation of an unknown three-component mixture:
Acidic component (CO2H)
Basic component (NH2)
Neutral component
Possible Unknowns:
Acids:
Separate by
acid/base chemistry
Bases:
Once separated and dry, take a m.p. of
each to determine the identity.
Take melting points the following
week.
Neutrals:

4. Chapter 5: Procedure 1 Example: Separate these three components
1. Use a flow chart to visualize
how the separation will work.
2. See photos/video.

5. Chapter 5: Procedure 1 Once the separation is complete:
Dry each, weigh and calculate % recoveries (assume you started with equal amounts of each)
Take a m.p. of each to determine identities
Either take an IR of the acidic component OR an NMR of the neutral component

6. Chapter 5: Procedure 2 Extraction of caffeine:
1. Use tea bags (odd # desks) or coffee bags (even # desks)
2. Steep tea or coffee bags in hot water
3. Extract aqueous solution with dichloromethane (CH2Cl2) to
isolate caffeine
Purify caffeine by sublimation
Weigh caffeine.
Compare caffeine content in tea and coffee with
hoodmate’s data; reference data.
caffeine

7. Extraction of caffeine:
Chapter 5: Procedure 2
Extraction of caffeine:
For extraction, use a separatory funnel;
Get a demo from your TA.
*A few, smaller extractions are better
than one big extraction.*
Vent funnel while shaking.
Aqueous layer: tea/coffee solution
Organic layer: dichloromethane/caffeine
Separatory funnel

8. Extraction of caffeine:
Chapter 5: Procedure 2
Extraction of caffeine:
Vent funnel while shaking.
Point away from face,
towards back of hood.

9. Chapter 5: Procedure 2 Once caffeine has been isolated, purify via
sublimation (heat solid  gas  pure solid).
Weigh the isolated caffeine and calculate the amount of caffeine per gram of tea or coffee.
Compare data with hoodmate; reference the data.