Cesium Salts of Phosphotungstic Acid: Comparison of Surface Acidity, Leaching Stability and Catalytic Activity for the Synthesis of β-Ketoenol Ethers

Catalytic activity of CsxH3-xPW12O40 catalysts were investigated in the synthesis of â-ketoenol ethers. It was found that activity; acidity, solubility and consequently, recoverability of these catalysts are related to cesium content. A series of β-ketoenol ether derivatives were synthesized by using Cs2.5H0.5PW12O40 catalyst in high to excellent yields. This catalyst showed highest surface acidity and lowest solubility in reaction media in comparison with the other cesium content salts.KEYWORDS Polyoxometalates, cesium salts, surface acidity, β-ketoenol ethers, heterogeneous catalysis