Extraction of organonitrogen compounds from five Chinese coals with methanol

Heteroatoms in coals, especially nitrogen 1 and sulfur, are considered as precursors of contaminator when using coals as fuels. For example, the nitrogen present in coals is emitted as NO x and N 3 O during combustion, causing acid rain, photochemical smog, greenhouse effects, and ozone-layer depletion. 2 The predominant source of NO x and N 2 O emissions is thought to be the nitrogen bound in the organic structures present in all coals. 5 Extensive investigations on the structures of organonitrogen compounds (ONCs) in coals have been performed to find out some effective approaches to nitrogen removal from coals 2,6 However, most of the investigations trying to understand ONC structures in coals by inseparable methods could not identify the structures of ONCs in coals at the molecular level. On the basis of a number of experiments, we established an approach to identify organic compounds in coals by a separable and nondestructive method, including fractional extraction and gas chromatography/mass spectrometry (GC/MS) analysis. Such an analysis provided the first molecular-level determination for organohalogens in coals, 7 an oxidized coal, 8 and hydrotreated coal residues 9 Here, we report our preliminary results about identification of ONCs in five Chinese bituminous coals by such a method.