Role of basicity, calcinations, catalytic activity and recyclability of hydrotalcite in eco-friendly synthesis of coumarin derivatives

• Synthesis using heterogeneous catalyst.
• Solvent free synthesis.
• Characterization by XRD and SEM.
• Role of basicity, aging time and catalytic activity.
• Novel catalyst system for synthesis of coumarin derivatives.

An efficient and simple protocol is described for synthesis of coumarin derivatives using Mg–Al-CO3 and Ca–Al-CO3 hydrotalcite as an environmental friendly and reusable heterogeneous catalyst under solvent free conditions. The catalysts were characterized by Hammett titration, SEM and XRD data. Present study revealed that catalytic activity and basicity depend on compositions of hydrotalcite. The calcined hydrotalcite with an Mg/Al of 3:1 derived from calcinations at 750 K was found to be suitable catalyst that gives the highest basicity and the best catalytic activity for this reaction. Catalyst allows short reaction time, high catalytic activity, easy to work up and is reusable. Step economy, atom efficiency and solvent free conditions are some important salient features of this protocol.

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