QUANTIFICATION OF NITROGEN FORMS IN ARGONNE PREMIUM COALS

X-ray photoelectron spectroscopy (XPS) was used to identify and quanti fy the organically bound nitrogen forms present in fresh Argonne Premi um coals. XPS spectra obtained on a wide variety of model compounds we re used to establish a curve resolution methodology. Pyrrolic nitrogen is the most abundant form of organically bound nitrogen, followed by pyridinic types. Quaternary nitrogen species were also identified. An analysis of the sensitivity of XPS for primary amines indicates that t hese species are not detected at concentrations above 5 mol %. A trend of decreasing level of quaternary nitrogen forms along with increasin g levels of pyridinic nitrogen was observed with increasing coal rank. The formation and reactivity of quaternary nitrogen forms in several coals were examined. Quaternary nitrogen forms decrease upon pyrolysis and hydropyrolysis. The level of quaternary nitrogen increases upon t reating high-rank coal with strong acid.