Effect of Imidazolium Based Ionic Liquids on Coal Exothermic Oxidation by Thermal Analysis Experiments

In order to study the oxidation-inhibiting effect of ionic liquid (IL) on coal, this paper successfully used six imidazolium based ionic liquids, [AOEmim][BF4], [HOEmim][BF4], [Amim][Cl], [Emim][AC], [Bmim][AC] and [Bmim][OTf] to dissolve and disperse coal. The exothermic oxidation of the raw coal and those pretreated by ILs were separately tested by Simultaneous Thermal Analyzer. The tested results show that there were more active groups left in the [AOEmim][BF4] and [Amim][Cl] pretreated coals. While, the [HOEmim][BF4], [Emim][AC], [Bmim][AC] and [Bmim][OTf] pretreated coals lost less mass ratio and the process was short, which shows that these four ionic liquids dissolved or destroyed more active groups of coal and inhibited the coal oxidation better than the [AOEmim][BF4] and [Amim][Cl] ionic liquids. Ionic liquid with a large anion and a cation substituted by simple chains and will improve the ionic liquid's destroying ability for coal's chemical structures.