Organic Chemistry II Lab
CHEM 2212L (Summer 2008)
School of Science and Technology
Georgia Gwinnett College
Experiment J. Aldol Condensations to Produce α,β-unsaturated Carbonyl Compounds:
Synthesis of trans-p-Anisalacetophenone
1. EXPERIMENTAL OBJECTIVES:
a. Synthesize an α,β-unsaturated carbonyl compound. .
b. Isolate the product.
c. Characterize and analyze.
d. Present, analyze, and discuss results in a written report.
2. SPECIAL INSTRUCTIONS:
a. Chemicals and solvents:
(1) NaOH (s),[1310-73-2]
(2) p-anisaldehyde, [123-11-5]
(3) acetophenone, [98-86-2]
(4) ethanol (95%), [64-17-5]
(5) methanol, [67-56-1]
(6) bromine in dichloromethane (test for unstaturation), [7722-64-7]
(7) Baeyer test (for unsaturation), ethanol (95%), KMnO4 (aq), [7722-64-7]
(8) trans-p-anisalacetophenone, [959-33-1]
b. In the first lab session you will isolate your crude product, then recrystallize 3/4 of
your crude product, saving 1/4 of the crude product for analysis in the un-recrystallized state.
The second lab session you will determine % yield of the recrystallized product, MP of crude
product and recrystallized product, and IR of starting materials, crude product, and
recrystallized product.
3. PROCEDURES:
Apparatus
1. Work at the bench top, not the hood. Begin cooling an ice bath for later use. Fill 3 small
test tubes with 95 % ethanol and cool them in the ice bath for later use.
Setting Up
2. Use the ADP to measure 0.200 mL of p-anisaldehyde, 0.200 mL of acetophenone, and
0.700 mL 95% ethanol. Use the smallest bar magnet. Put your vial in a small beaker on your
stirplate to avoid tip-over spills. While the reaction is running, do IRs of the starting
materials.
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Organic Chemistry II Lab
CHEM 2212L (Summer 2008)
School of Science and Technology
Georgia Gwinnett College
Aldol Reaction, Work-Up, and Isolation
3. Instead of 5-10 drops of cold 95% ethanol, use as much of the cold three small test tubes
of 95% ethanol as needed to get a thorough washing of the crude product. Let the crude
product air dry for a few minutes on your watch glass.
4. Separate approximately 1/4 of the crude product and place into an open top, wide-mouth
sample vial for storage and evaporation of solvent until the second lab session.
5. Separate approximately 3/4 of the crude product and place it into your Craig tube for
recrystallization from methanol. You may need to stir and/or gently warm the Craig tube
with crude product and methanol in your sand bath to get the solid to go into solution. Be
careful and patient with this step, not too much heat. Then cool the Craig tube in air, then in
an ice bath to enable recrystallization. After recrystallization, use the centrifuge to separate
crystals from solvent/impurities. Place the recrystallized product in an open top, wide-mouth
sample vial for storage and evaporation of solvent until the second lab session. If you have
time, do IRs of starting materials.
Analysis
6. Determine % yield of your recrystallized product.
7. Conduct melting point analysis of the crude and recrystallized product.
8. Conduct IR analysis of starting materials (one IR stacked with p-anisaldehyde and
acetophenone) and product (one IR stacked with the crude product and the recrystallized
product).
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