Relationship Between Benzophenone And Acetone

Introduction: Benzaldehyde and acetone in ethanol solvent undergoes cross aldol condensation reaction to give dibenzalacetone. This reaction known as the Claisen-Schmidt reaction.
Reaction:
The benzalacetone, formed as an intermediate. Benzalacetone once formed, then easily react with another molecule of benzaldehyde to give dibenzalacetone.
Procedure:
1. Take 8 mL of benzaldehyde in 100 mL beaker.
2. Add 2 mL of acetone to the benzaldehyde and mix.
3. Dissolve 5 g of NaOH into 50 mL of water and 40 mL of ethanol.
4. Add half of the mixture of benzaldehyde and acetone (from step 2) to the NaOH solution. Keep the temperature below 25°C.
5. After 15 minutes, add in the remainder of the mixture to the NaOH solution and rinse the container

2
Preparation of benzhydrol from benzophenone (Reduction)
Introduction: Reduction of benzophenone to benzhydrol carried out by using mild reducing agent sodium borohydride NaBH4 followed by acid hydrolysis.
Reaction:

Procedure:
1. Place 0.64 g of benzophenone and 4 mL of methanol in a 100 mL conical flask.
2. If necessary, warm the mixture to dissolve the benzophenone and then allow to cool at room temperature.
3. To this benzophenone solution, add in one portion 0.64 g of sodium borohydride.
4. Swirl the flask and allow the reaction mixture to stand at room temperature for 20 minutes.
5. Add 2 mL of cold water and warm on a steam bath for 5 minutes.
6. Cool the resulting mixture in an ice bath to precipitate a solid.
7. Collect the solid using vacuum filtration and air dry it.
8. Determine the weight and melting point of the solid.
9. Calculate the % yield of the product.
10. Obtain and interpret an infrared spectrum of the product.
Note: Use the NaBH4 immediately after weighing. The NaBH4 is unstable to water It reacts vigorously with acid with the evolution of hydrogen gas..
Mechanism:
Step I: One molecule of reducing agent sodium borohydride consumes four molecules of