Condensation of ammonium phosphates with urea at 120 °C
Abstract
The pyrolysis of NH4[H2PO4] and [NH4]2[HPO4] in the presence of urea at 120 °C has been followed by 31P n.m.r. spectroscopy and shown to go through a sequence of reactions involving di- and tri-phosphates and eventually leading to ammonium hexacyclophosphate (NH4PO3)6 as the principal product. The heating of ‘urea phosphate’, (NH2)2CO·H3PO4, at 120 °C has also been studied by 31P n.m.r. spectroscopy.