Identification of organonitrogen and organooxygen compounds in the extraction residue from Buliangou subbituminous coal by FTICRMS

• Numerous species in soluble portions (SPs) from the ER thermal dissolution were detected.
• Basic N1Ox class species with DBE = 4–20 are dominant in the SPs.
• Main acidic oxygen species in the SPs are Ox class species with DBE = 1–18.
• The species with 3 aromatic rings are predominant in the SPs.

Organonitrogen and organooxygen compounds (ONCs and OOCs) in the extraction residue (ER) from Buliangou subbituminous coal were characterized with an electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (ESI FTICRMS). Pyrrolic and hydroxy are the most abundant nitrogen and oxygen moieties on the ER surface according to analysis with an X-ray photoelectron spectrometer. The m/z values of ONCs and OOCs detected by FTICRMS mainly range in 200–450. The main basic ONCs detected are N1Ox (x = 0–1) class species with double bond equivalent (DBE) values of 4–20 and carbon numbers (CNs) of 12–32. The core moieties in most of the basic N1Ox (x = 0–1) class species are aromatic rings (ARs), including benzene, pyridine, quinoline, and acridine rings. Ox (x = 1–4) class species are the main OOCs in the soluble portions from thermal dissolution of the ER. In acidic O2 class, the most abundant species with DBE = 1, 2, 9, and 12 and CNs of 13–21 can be observed. The main acidic O1 class species are alkylarenols with 1–6 ARs, while most of the acidic O3 class species contain an AR, such as a naphthalene, dihydroanthracene, or anthracene ring, with at least a hydroxy or carboxy group.