Zhan-Ku Li

Sequential Thermal Dissolution of Geting Bituminous Coal in Low-boiling Point Solvents

Sequential thermal dissolution (STD) of Geting bituminous coal (GBC) in benzene, methanol, ethanol, and isopropanol was conducted at 150 to 300°C for 2 h. Anthracene was added into the system as the hydrogen acceptor to trace hydrogen transfer (HT) behavior during the STD. All of the soluble portions (SPs) were analyzed with a gas chromatograph/mass spectrometer. The once-through yields of SPs did not fluctuate obviously with raising the thermal dissolution (TD) temperature from 150 to 250°C, but significantly increased over 250°C. HT from GBC to anthracene in benzene, methanol, and ethanol occurred at 300°C and in isopropanol at 250°C. Unlike TD in benzene, alkanolysis significantly proceeded during TD in alkanols at 300°C.

Characterization of Extracts from Geting Bituminous Coal

Geting bituminous coal (GBC) was exhaustively extracted with isometric carbon disulfide/acetone at ambient temperature to provide twenty extracts and a residue. The extracts were characterized by gas chromatography/mass spectrometry (GC/MS), Fourier transform infrared spectroscopy, and atmospheric pressure solids analysis probe time-of-flight mass spectrometry. GBC and its residue were observed with a scanning electron microscope. The total extract yield is ca. 11.5%. The GC/MS-detectable compounds in extract 1 can be classified into alkanes, cyclanes, arenes, cyclenes, and heteroatomic compounds, among which arenes are predominant. The number of detected compounds decreases and they have higher molecular masses with increasing extraction times. The combination of multiple techniques facilitates understanding the molecular composition of the extractable species from coals.

Characterization of Oxygenates in Zhundong Subbituminous Coal by Gas Chromatography/Mass Spectrometry

ABSTRACT Zhundong subbituminous coal was extracted with isometric carbon disulfide/acetone mixed solvent at room temperature and the residue was subjected to thermal dissolution in methanol from 50 to 200°C. According to gas chromatography–mass spectrometric analysis, the soluble portions (SPs) consist of alkanes, alkenes, arenes, phenols, esters, ketones, alcohols, aldehydes, nitrogenates, and sulfonates, among which oxygenates are the most abundant. Raising the dissolution temperature increased the SP yields. Esterification and transesterification resulting in the cleavage of oxygen-containing bridged bonds caused the generation of esters at temperatures over 100°C.