煤沥青溶解性及可溶物中的多环芳烃分布

选用石油醚、甲醇和二硫化碳等9种常见有机溶剂对山西某厂所产煤沥青(简称CTP)进行超声萃取,对比萃取率和溶剂溶解度参数,发现溶解度参数在9~10(cal/cm3)1/2的溶剂对CTP煤沥青有较好的溶解性。采用气相色谱仪(GC)定量分析各萃取物中多环芳烃的含量,然后对各萃取物进行红外光谱(FTIR)测试,并且对FTIR光谱图进行分峰拟合,以此来研究煤沥青中芳环结构在不同溶剂中的分布特征。结果表明:在9种溶剂的萃取物中均检测到了美国环保署优先监控的除苊烯外的有毒多环芳烃;各萃取物中荧蒽的含量均为最高,且石油醚和正己烷对荧蒽的萃取选择性较好,通过后续分离手段有望获得荧蒽纯品;各萃取物中检测到的多环芳烃主要以高致癌的苯并芘和二苯蒽等环数为4或5的芳烃为主,且环己烷可高选择性地萃取这些芳烃,因此在对CTP进行脱毒时,可选择环己烷作为介质,以实现煤沥青高效脱毒的目的。根据红外拟合参数结果,对比了各萃取物的芳香度和芳环的缩合程度,发现二硫化碳和甲苯等萃取物的芳香度和芳环缩合度较大,可作为生产炭材料的前驱体。

Solubility of a coal tar pitch and distribution of polycyclic aromatic hydrocarbons in soluble portion

In this study,the coal tar pitch (CTP) from a coking factory of Shanxi was extracted with nine organic solvents including petroleum ether,methanol and carbon disulfide under ultrasonic wave condition.Comparing the extract yield and solubility parameter of solvents,it could be found that the solvent with solubility parameter of 9-10(cal/cm3)1/2 have a good solubility for CTP.Polycyclic aromatic hydrocarbons (PAHs) in the extracts were quantitatively analyzed using gas chromatography (GC).Furthermore,the extracts were examined by FTIR spectrometry,and the spectra were fitted,in order to investigate the dissolution characteristics of coal tar pitch in organic solvents.The results indicated that toxic PAHs except acenaphthylene preferentially monitored by Environmental Protection Agency (EPA) were detected in each extract.Moreover,the content of fluoranthene was the highest,and petroleum ether and hexane had a good extraction selectivity for fluoranthene,suggesting that pure fluoranthene may be obtained by next separation.PAHs in each extract mainly consisted of highly carcinogenic PAHs with 4-5 rings,such as benzopyrene and dibenzanthracene,and cyclohexane could extract these PAHs with high selectivity,indicating that cyclohexane could be used as the solvent for achieving the effective detoxification of CTP.According to the fitted peaks of the FTIR spectra,the aromaticity of each extract,and the condensed degrees of aromatic rings were compared,respectively,and it could be concluded that the carbon disulfide and toluene extracts have a high aromaticity and these aromatic rings have a high condensed degree,suggesting these extracts may be a good precursor for producing carbon materials.