Aldol-condensation

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THE ALDOL CONDENSATION REACTION:PREPARATION OF BENZALACETOPHENONES.

Introduction:

Benzaldehyde reacts with a ketone in the presence of a base to yield a alpha/beta-unsaturated ketone. This is an example of crossed aldol condensation reaction where the intermediate undergoes dehydration to produce a resonance stabilized unsaturated ketone.
The mechanism of this mechanism is illustrated below in equation 1. The protocol for this reaction has 3 basic steps: 1)Running the reaction, 2)Isolation of crude product, and 3)Crystallization of 3-nitrobenzaldehyde. Please refer to the (Procedure) section below for an in depth description.


Equation 1.

Procedure:

1. RUNNING THE REACTION.
2. First, obtained .160 grams of 3-nitrobenzoaldehyde and it was placed in a 5ml conical vial.
3. Then .15ml of acetophenone and .80ml of 95% ethanol was added to the vial.
4. For safety the 5ml conical vial was placed in a 50ml beaker and then the contents in the 5ml vial were stirred for about 1 minute.
5. Next, .10ml of NaOH was added to the mixture and the contents were stirred again until it solidified into a slimy mixture.
6. ISOLATION OF CRUDE PRODUCT.
7. In order to isolate the crude product 2ml of ice-water was added and the mixture was then transferred to a small beaker containing 3ml of ice-water.
8. The contents were then stirred in order to break up the precipitate.
9. The crude product was obtained via vaccume filtration on a Hirsch funnel.
10. It was then allowed to dry for 25 minutes and then the product was weighed and percent yield was calculated.
11. CRYSTALLIZATION OF 3-NITROBENZALDEHYDE.
12. First obtained .25 grams of sample from about 1.5ml of methanol.
13. The tube was then scratched in order to induce crystallization while cooling.
14. Finally, the melting point test was conducted in order to test for impurities and quality of product.

Data:

MASS AND VOLUMES OF COMPOUND’S USED IN REACTION

MA...