Identification of Organonitrogen Compounds in Petroleum Ether-soluble Fraction from a High-temperature Coal Tar

A high-temperature coal tar collected from Xuzhou Coking Plant, Saint-Gobain Pipelines (Xuzhou) Co., Ltd. was extracted with petroleum ether (PE) under ultrasonic irradiation and in a Soxhlet extractor. The residue was then extracted with methanol in the Soxhlet extractor. All the extracts were analyzed with gas chromatography/mass spectrometry (GC/MS). More than 250 organic compounds were detected in the PE-soluble fraction, but no GC/MS-detectable species (GC/MS-DSs) in the methanol-soluble but PE-insoluble fraction, indicating that all the GC/MS-DSs were extracted as PE. The GC/MS-DSs include various nitrogen-containing ones, many of which were seldomly reported. Nitrogen-containing organic compounds (NCOCs) detected are aniline, indole, quinoline, isoquinoline, methylquinolines, naphthonitriles, 8-(dimethyl-amino)-1-naphthonitrile, 3-methylindazole, acridine, benzoquinoline, benzoacridine, benzoisoquinolines, carbazole, methylcarbazole, phenanthridine, (Z)-N-(1-phenylethylidene)methanamine, benzocarbazoles, acenaphthopyridine and 2-methylcarbazole. Understanding molecular composition of the NCOCs in coal tar is important for developing an effective coal tar separation process.