Energy Fuels

Zhundong subbituminous coal was extracted with isometric carbon disulfide (CDS) and acetone mixed solvent (IMCDSAMS) to obtain the extract (E-M). EM was fractionated with petroleum ether (PE), CDS, methanol, acetone, IMCDSAMS, and tetrahydrofuran to obtain the sub-extracts 16 (ES1-ES6), respectively. ES2 was sequentially eluted with PE and 30, 50, and 70% CDS/PE mixed solvents through a silica-gel-packed column to obtain eluted fractions 14 (EF1-EF4). A series of condensed aromatic lactones (CALs) were detected in EF4. Among them, 5H-phenanthro[1,10,9-cde]chromen-5-one and 4H-benzo[5,10]anthra[1,9,8-cdef]chromen-4-one were further isolated as nearly pure compounds by gelatin column chromatography and identified by gas chromatography/mass spectrometry, atmospheric solid analysis probe/time-of-flight mass spectrometry, Fourier transform infrared spectrometry, H-1 nuclear magnetic resonance spectrometry, and 1H1H correlation spectrometry. Main fragmental ions in the mass spectrum of each CAL are formed by successive losses of m/z 28 (CO) and 29 (-CHO) from the molecular ion. An effective way to isolate CALs from low-rank coals was provided in this paper.Zhundong subbituminous coal was extracted with isometric carbon disulfide (CDS) and acetone mixed solvent (IMCDSAMS) to obtain the extract (E-M). EM was fractionated with petroleum ether (PE), CDS, methanol, acetone, IMCDSAMS, and tetrahydrofuran to obtain the sub-extracts 16 (ES1-ES6), respectively. ES2 was sequentially eluted with PE and 30, 50, and 70% CDS/PE mixed solvents through a silica-gel-packed column to obtain eluted fractions 14 (EF1-EF4). A series of condensed aromatic lactones (CALs) were detected in EF4. Among them, 5H-phenanthro[1,10,9-cde]chromen-5-one and 4H-benzo[5,10]anthra[1,9,8-cdef]chromen-4-one were further isolated as nearly pure compounds by gelatin column chromatography and identified by gas chromatography/mass spectrometry, atmospheric solid analysis probe/time-of-flight mass spectrometry, Fourier transform infrared spectrometry, H-1 nuclear magnetic resonance spectrometry, and 1H1H correlation spectrometry. Main fragmental ions in the mass spectrum of each CAL are formed by successive losses of m/z 28 (CO) and 29 (-CHO) from the molecular ion. An effective way to isolate CALs from low-rank coals was provided in this paper