Study On The Transformation Of Coals In1-Butyl-3-methyl Imidazole Chloride

To reveal the weak bonding structure and its dissociation of lignite from themolecular level is not only the major problems faced by coal chemistry, but the theoreticalbasis of technical breakthrough of lignite staged conversion. This thesis based on the highefficient depolymerization performance of Xianfeng lignite in ionic liquids, the thermallydissolved products from Xianfeng lignite extracted by ionic liquid (1-butyl-3-methylimidazole chloride：[Bmim]Cl) were separated and analyzed to explore the structureinformation of lignite in this thesis. Based on dissolution performance of ionic liquids onhydrogen bonds in lignite, conversion behaviors of lignite after pretreatment with ionicliquid were investigated. Finally the thermal extractions of different types of coal in ionicliquid were carried out to explore the effect of coal type on the thermal extraction of coalin ionic liquid.It was found that there are a large number of hydrogen bonds presenced in Xianfenglignite. The thermally dissolved products of Xianfeng Lignite during microwaveextraction in ionic liquid ([Bmim]Cl) can be separated into water-solubles (2%), theacetone-solubles (11.5%), pyridine-solubles (40.4%), and pyridine-insolubles (46.1%).Water-solubles mainly contains fatty compounds and a small amount ofmonoaromatics biaromatics, triaromatics, tetracyclic aromatics, and pentacyclic aromaticcompounds. Acetone-solubles mainly contains long chain fatty compounds and sometricyclic aromatics and tetracyclic aromatic compounds. Pyridine-solubles andpyridine-insolubles mainly contain the tricyclic aromatics and pentacyclic aromaticcompounds. Microwave extraction of lignite in ionic liquid changed the structure of lignite.Extracion temperature significantly affects the types and the distribution of chemicalbonds in the residue obtained from microwave extraction with ionic liquid.TG-DTG analyses show that the pretreatment of Xianfeng lignite with ionic liquid[Bmim]Cl has significant influence on the pyrolysis behaviors of Xianfeng lignite. Weightloss rate of pretreated Xianfeng lignite increases than that of raw coal during pyrolyis. Thetemperature of the maximum weight loss rate of pretreated Xianfeng lignite is30℃lower than that of raw coal; the pretreatment of Xianfeng lignite with ionic liquid([Bmim]Cl)leads to the increase of the liquefaction oil yield of Xianfeng lignite and the improvementof the oil quality.Under the same extraction conditions the extraction yield of different type of lignitein ionic liquid [Bmim]Cl is significantly different. The extraction yiled order is: XF lignite> SL lignite> XLGL lignite.The extraction yileds of different coals in ionic liquid alsohave large difference: SF>FM> QM> SM. It is found that the extraction yileds increasewith the increase of oxygen content of coal, and decrease with the increase of carboncontent. The thermal extraction of coal with ionic liquid [Bmim]Cl dissociates thehydrogen bonding and ether bond in coal in varying degrees, which leads the thermallydissolved products easily to pyrolyze.