Abstract

Solvent-free Claisen-Schmidt condensation (CSC) for the synthesis of chalcone has been studied using MoO₃/ZrO₂ material as solid acid catalyst. A series of MoO₃/ZrO₂ catalysts with various MoO₃ loadings (10-30 wt%) were prepared using modified precipitation method. The catalysts were extensively characterized using various techniques viz., TG-DTA, XRD, N₂ Sorption, BET-surface area, NH₃-TPD, Raman and FT-IR spectroscopies, AAS, EDX, TEM and SEM. The detailed parametric studies were carried out to optimize the reaction parameters in order to achieve maximum selectivity with high % yield of chalcones. Substituted benzaldehyde and acetophenone were used as reactants to study the effect of electron withdrawing and electron donating groups on the activity of catalyst. 15 wt% MoO₃/ZrO₂ catalyst prepared using modified preparation technique proved to be an excellent heterogeneous catalyst for solvent free synthesis of chalcone with yield as high as 93 %, by using only 1.5 wt% of catalyst.

Keywords: Chalcone, modified precipitation, molybdenum, raman, zirconia.

Graphical Abstract