Introducing Red Mud as an Efficient Catalyst for One-pot Synthesis of 3-Substituted Coumarins and Investigation of the Reaction Thermodynamics Using Computational Chemistry

One-pot synthesis of 3-substituted coumarins using Red mud (RM) which emerges as a by-product from the alumina producing process as a catalyst via Knoevenagel condensation of 2-hydroxybenzaldehyde derivatives and malonate derivatives are investigated. Reaction carried out under various conditions and the best results are obtained when the reaction is done under microwave irradiation. RM showed an efficient catalytic activity in this reaction. The catalyst can be used for at least four times after reactivation without remarkable losing in its efficiency. Finally, some of the thermochemical properties such as enthalpy and Gibbs free energy of formation for the synthesized coumarins are calculated using quantum chemistry, and also an electrostatic potential map of some of the synthesized coumarins was obtained using computational chemistry software which could be so helpful for the analysis of active reaction sites of coumarins.