Synthesis and Characterization of 1,3-thiazolidin-4-ones Using Recyclable, Magnetically Nanocatalyst in the Solvent-Free Microwave Medium

In the present work, an environmentally friendly nano-catalyst (γ Fe2O3RHA@SO3H) was used for the preparation of 1,3-thiazolidin-4-ones analogs (T1-T9) from Schiff bases (S1-S9) by microwave irradiation. The recycled catalyst (γ Fe2O3RHA@SO3H) was produced from silica derived from rice husk, which was first modified with ferrite nanoparticles (Fe2O3), then with sulfuric acid. The characterization of the (γ Fe2O3RHA@SO3H)) nanocomposite and its characteristics were achieved using various techniques including, XRD, total acidity and basicity utilizing CO2/NH3-TPD, textural properties through Brunauer-Emmett-Teller (BET), functional group determination by FTIR; surface morphology through FESEM and TEM, magnetic properties by a vibrating sample magnetometer (VSM), and thermal stability via TGA. The VSM data demonstrated that the superparamagnetic catalyst (γ Fe2O3RHA@SO3H) can be simply separated and recovered after reaction completion employing an external magnet. The attained data revealed that the optimum reaction parameters of the catalyst γ Fe2O3RHA@SO3H for producing (S1-S9) were 5% (the catalyst amount), ethanol (the reaction solvent), 1h (the reaction time), and 70°C (the reaction temperature) with a maximal yield up to 94%. The reusability study and reactivation results disclosed that the nano-bifunctional magnetic catalyst (γ Fe2O3RHA@SO3H) can preserve a high catalytic activity after at least three reuses. The findings also indicated that (γ Fe2O3RHA@SO3H) has superior magnetic characteristics, rendering it to be used as a heterogeneous catalyst in creation of 1,3-thiazolidin-4-one derivatives with high proficiency under simple reaction circumstances.