A comparative investigation of palmitic acid esterification over p-sulfonic acid calix[4]arene and sulfuric acid catalysts via 1H NMR spectroscopy

► Calix[4]arene catalyst is highly active for fatty acids esterification. ► Kinetic data showed that the calix[4]arene was as active as H2SO4. ► p-sulfonic acid calix[4]arene is a recoverable and reusable catalyst. ► The order in relation to calix[4]arene and H2SO4 was 0.57 and 1.0 respectively.