Solvent-free synthesis of chalcone by aldol condensation catalyzed by solid sodium hydroxyde (NaOH) / Muhamad Faridz Osman

Chalcones represent a group of compounds with interesting biological activities that are
formed from an aldol condensation between a benzaldehyde and an acetophenone in the
presence of NaOH as a catalyst. Although traditionally synthesized using aqueous sodium
hydroxide in organic solvents, in this study three different chalcones were synthesized
using a solventless procedure. The solvent-free synthesis of three chalcones was carried
out by grinding the benzaldehyde (3-nitro, 4-methoxy, 4-chloro) and 4-
methoxyacetophenone in the presence of solid sodium hydroxide with a mortar and
pestle. Chalcones were obtained in high yields (76-86%), high purity, and shorter
reaction time (within five minutes). The results seemed to indicate the success of the
solvent-free aldol synthesis which is simple, highly efficient and eco-friendly. For
comparison, the three chalcones were also synthesized by the traditional aldol
condensation catalyzed by aqueous sodium hydroxide in ethanol afforded lower yield
(62-72%) and required longer reaction time (62-75 min).