Acetophenone reacts with potassium hydroxide in ethanol to form the enolate form of acetophenone (the first step in the aldol condensation). In order to avoid side reactions such as multiple condensations, polymerizations, and rearrangements, the reaction is carried out at low temperatures.
2. then add the enolate anion to the unreacted acetophenone molecule, then perform acid-base reaction , and finally eliminate a water molecule and the formation of chalcone derivate