Evolution of nitrogen functionalities in carbonaceous materials during pyrolysis Pels, J R; Kapteijn, F; Moulijn, J A; Zhu, Q; Thomas, K M [Delft University of Technology, Delft (Netherlands). Industrial Catalysis - CPT] 01 COAL, LIGNITE, AND PEAT; CARBONACEOUS MATERIALS; PYROLYSIS PRODUCTS; NITROGEN OXIDES; NITROGEN; CHEMICAL REACTIONS; PYROLYSIS; ORGANIC NITROGEN COMPOUNDS; QUANTITATIVE CHEMICAL ANALYSIS; LIGNITE; CHARS; PHOTOELECTRON SPECTROSCOPY; ACRIDINES; CARBAZOLES; PAN; PYRIDINES; X RADIATION X-ray photoelectron spectroscopy (XPS) was used to investigate the fate of nitrogen functional forms present in a lignite and its chars, chars derived from the model compounds acridine, carbazole and polyacrylonitrile (PAN). Four different peaks have been found in the XPS patterns, corresponding to at least five different nitrogen functional forms, all being aromatic moieties. The XPS patterns of the synthetic chars were recorded for identification purposes. The distribution of nitrogen functional forms changes with increasing severity of the pyrolysis conditions. Under mild pyrolysis conditions, firstly unstable functionalities like pyridones, protonated pyridinic-N and N-oxides of pyridinic-N are converted to pyridinic-N and secondly pyrrolic-N is converted to pyridinic-N during condensation of the carbon matrix. During the condensation process, nitrogen is eventually present in 6- membered rings located at the edges of the graphene layers as pyridinic-N can be formed. During pyrolysis, differences in nitrogen distribution of the char precursor have diminished. It is presumed that the remaining small differences in the nitrogen distribution of the chars cannot significantly influence the formation of nitrogen oxides during combustion of the chars. 73 refs., 12 figs., 4 tabs. United Kingdom 1996-12-31 English Journal Article Journal Name: Carbon; Journal Volume: 33; Journal Issue: 11; Other Information: PBD: 1995 Medium: X; Size: pp. 1641-1653 https://doi.org/10.1016/0008-6223(95)00154-6 [] 11 33 Journal ID: CRBNAH; ISSN 0008-6223; TRN: 960200219 CLA; SCA: 010600; PA: CLA-96:020219; EDB-96:012275; SN: 96001521632 2010-12-29 167107