what are the aldol condensation reactions and canizaros reaction?

Aldol Reaction:  This reaction takes place between two molecules of carbonyl compounds; one molecule should have at least two a-hydrogen atoms. In this reaction best result is obtained when

 

Both molecule are the same or one should have no ?-hydrogen atom and other should have at least two ?-hydrogens.

 

The reaction is two step reaction. First step is aldol formation and second step is dehydration of aldol.

 

 

 

Cannizzaro reaction  

 It involves a reaction with aldehydes which have no alpha hydrogen atoms. It is a disproportionate reaction. 

                       KOH

2C₆ H₅ CHO ————?C₆H₅ CH₂ OH + C₆ H₅ COOK

Benzaldehyd                          Benzl alcohol        Potassium benzoate