Mixed Aldo\'s Condensation of benzaldehyde and acetone: Why was residual dichlor
ID: 513625 • Letter: M
Question
Mixed Aldo's Condensation of benzaldehyde and acetone:
Why was residual dichloromethan boiled off, prior to filtration of acidified mixture? Dissolve the remainder of the product from Part B in 6 mL o Stir this mixture and add a Dissolve a total 22 mL solution ("clorox portiont Cool the with a water bath whenever it becomes warm. Continue to stir the reaction mixture for at least 15 minutes after the last addition of the reagent/ Then add 1/2 mL of 6ceto do destroy the excess sodium hypochlorite/Transfer the reaction mixture to a 60-mL separatory funnelladd 5 mL of saturated aqueous sodium chloride and extract the solution three times with 3-mL portions of dichloromethanel Transfer the aqueous layer to a 40-mL beaker. Then use concentrated hydrochloric acid (about TmL will be required)
Explanation / Answer
The product of the reaction, dibenzalacetone is less polar than the starting carbonyl compounds due to the presence of two phenyl rings. Dichloromethane is an excellent solvent for medium to non-polar organic molecules. Hence, dibenzalacetone is soluble in dichloromethane. If the excess dichloromethane is not boiled off prior to filtration, the product will solubilize in dicloromethane and be lost during the re-crystallization step.