关键词: 煤焦油, 沥青质, 溶剂分析

Abstract: Solvent analysis is a method for quantitative separation of coal tar into toluene insoluble，asphaltene (toluene soluble，pentane insoluble)，and oil (pentane soluble). The prime objective was to identify the variables in the procedure，including aromatic solvent type，extraction method，amount of toluene solution concentrate (degree of toluene boil-off) ，alkane solvent type，and ratio of n-heptane to toluene solution concentrate that affected the precipitate obtained for asphaltene content. Substitution of toluene with benzene and extraction method did not have a large effect on the precipitate reported for asphaltene. Heptane was chosen as alkane solvent instead of pentane. However amount of toluene solution concentrate and ratio of n-heptane to toluene solution concentrate did have a large effect on the precipitate reported as asphaltene. Coal tar from northern Shaanxi province was tested. With the suitable time of ultrasonic extraction for 3 hours，toluene solution concentrate of 9mL，a 20-fold of n-heptane over toluene solution concentrate，the asphaltene precipitate determined was 13.4%. The separation conditions of asphaltene determination should be indicated when studying the properties and structure of asphaltene from coal tar，since the coal tar separation technique have a large effect on asphaltene precipitated.

Key words: coal tar, asphaltene, solvent analysis