Differential scanning calorimetry study of reactions of phenyl glycidyl ether with phosphoric acid

Abstract

The reactions of phenyl glycidyl ether (PGE) with phosphoric acid in three molar ratios have been studied by means of DSC alone. The results obtained from isothermal measurements are as follows: AH = -91.0 k J/mole PGE (1 -1 molar ratio); AH = -100.5 kJ/mole PGE (1 : ]molar ratio).The DSC curves obtained from dynamic experiments are multipeaked and give AH values higher than those obtained from isothermal measurements. These results can be explained by taking into account the acid concentration, the different reactivities of the hydrogens of the phosphoric acid and the possibility that secondary reactions occur. Analogous values for the reaction of an epoxide with inorganic polybasic acids are not to be found.The aim of this work was to study, by means of DSC only, the reaction of phosphoric acid with a simple epoxide compound, such as phenyl glycidyl ether. ExperimentalThe following reactants were used: phenyl glycidyl ether 95% (Fluka); orthophosphoric acid 99% (Carlo Erba). These were used without further purification.