The first principle of Green Chemistry is to prevent or reduce the production of waste whenever possible. The use of a solvent-free reaction helps to eliminate this waste production and results in a safer and more environmentally friendly synthesis of chalcones.

In our solvent-free synthesis reaction, we were able to synthesize several chalcones from substituted benzaldehyde and acetophenone starting materials. The use of a ball mill and finely ground sodium hydroxide resulted in higher percent yields and more pure products then has been previously reported. In addition, we have characterized the chalcone products by melting point, Carbon-13 NMR and Proton NMR.

The synthesis of chalcones is an excellent way to demonstrate both an Aldol condensation and the properties of a highly conjugated system in an undergraduate laboratory setting. In addition, chalcones have use in industry as the starting material in many medications and also as a component of many photoresist compounds.