Study of the reaction between urea and formaldehyde by dsc and ¹³C NMR spectroscopy

Abstract

Abstract The reactions of urea with formaldehyde were studied by means of 13 C NMR spectroscopy and differential scanning calorimetry (DSC) in acid and neutral medium, the temperature range being between 290 and 390 K. At higher pH the peak of the DSC curve splits into two peaks one of which belongs to the addition of formaldehyde to urea and the second to the subsequent condensation of the latter. For both reactions, the activation energy, heat of polymerization, reaction order and temperature maximum have been determined. The usefulness of DSC to study the kinetics of more complex polycondensation reactions was established.