Question

Aldol condensation reaction requires the loss of a molecule of water and hence performing the reaction in water should disfavor this reversible dehydration from occurring. Based on your observations during the laboratory, provide a reasonable explanation as to why the condensation product is observed at all? (Note: Heat accelerates the reaction in reach equilibrium but DOES NOT directly favor the Aldol Condensation product).

Answer 1

Aldol condensation proceeds by abstraction of a proton from the ketone and then attack of enolate on to the aldehyde substrate. The reaction is exothermic in nature. The stability of enolate is what favors the formation of aldol product. Once the first step of aldol is done, readily the molecule looses a water molecule to form a more stable lower energy alpha,beta-unsaturated ketone product. The formation of this end product is another driving force for the aldol condensation reaction to occur.