不同煤级煤四氢呋喃阶段萃取物的化学组成与动力学机制

Chemical composition and its kinetics mechanism of tetrahydrofuran fractional extracts from different rank coals

为了探讨溶剂萃取过程中不同煤级煤的小分子化合物溶出行为及其机制,以四氢呋喃(THF)为溶剂,对褐煤、长焰煤、肥煤、贫煤和无烟煤进行了分次索氏萃取,借助于柱层析法和气相色谱-质谱联用仪(GC-MS),分析了不同分馏时间段各类煤的萃取率、族组成和化学组成的差异及其实质。结果表明:煤的萃取过程可划分为2个阶段,其中第Ⅰ阶段萃取速率远大于第Ⅱ阶段;相比于第Ⅰ阶段,第Ⅱ阶段的萃取物中烃类含量较低,非烃类含量较高;除了褐煤以外,随着萃取时间的增加,其他煤的萃取物中化合物的种类逐渐减少;各类煤的萃取物中,杂环化合物含量高且种类多,相比而言芳烃在中级烟煤萃取物中含量较高,而脂肪烃中长链烷烃在中低级煤萃取物中含量较大。

To investigate the dissolution behavior and its mechanism of small organic molecular compounds from coals with different ranks such as brown coal,long flame coal,fat coal,meager coal and anthracite,the coal samples were extracted in time intervals with tetrahydrofuran( THF). By means of column chromatography and gas chromatography-mass spectrometry( GC-MS),the difference and origin of the extraction rate,group composition and chemical composition of the extracts were analyzed.The results show that the extraction process of the coal samples can be divided into two stages,and the extraction rate is much higher in stage Ⅰ than that in stage Ⅱ.Compared with stage Ⅰ,the extracts in stage Ⅱ have more hydrocarbons and less non-hydrocarbons.With the increase of extraction time,the types of extracted compounds from different rank coals gradually decreased except brown coal.In the extracts,heterocyclic compounds are abundant in content and more in type.By contrast,the aromatics in the extracts of medium-rank bituminous coal andlong-chain alkanes in the extract of low-medium rank coals are more abundant.