Cesium salt of 2-molybdo-10-tungstophosphoric acid as an efficient and reusable catalyst for the synthesis of uracil derivatives via a green route

Abstract

A solid catalyst, cesium salt of 2-molybdo-10-tungstophosphoric acid (Cs_2.3H_0.7PW₁₀Mo₂O₄₀) named as Cs-3, was synthesized by a simple, cheap, clean, and eco-friendly method. The physicochemical properties of the synthesized catalyst were studied via FTIR spectroscopy, XRD, EDX, ICP-AES, SEM-TEM, and BET techniques. The precursor 2-molybdo-10-tungstophosphoric acid (H₃PW₁₀Mo₂O₄₀) was easily soluble in water and other polar solvents. Moreover, their cesium salts Cs_xH_3−xPW₁₀Mo₂ with Cs content in the range x = 2.0–2.5 were insoluble in water and other polar solvents. The surface area of the precursor (5.483 m² g⁻¹) increased after partial proton exchange by Cs⁺ ions (111.732 m² g⁻¹), and all samples with x > 1 were resistant to leaching of active components and can be recycled without obvious loss of activity. This catalyst used for the synthesis of uracil derivatives via a green route under solvent free conditions at 70 °C gives higher yield within a shorter reaction time. The catalyst was found to be more active and reusable over nine runs with a negligible loss of activity.