Supercritical Alcoholysis Of Xilinhaote And Huolinguole Lignites

Because of limitation of their characteristic, lignites have not been effectively utilized. Xilinhaote lignite (XLHTL) and Huolinguole lignite (HLGLL) were chose in this study. The research was an approach to the dehydration of lignite taken the acetone as a dehydrated medium. The alcoholysis reaction under supercritical condition were investigated, and isolated and analyzed the reaction mixture. Based on the above, some related model compounds were chose to react in the same conditions in order to deduce the mechanism of reaction. The reactions of methanol itself in supercritical condition and reaction mechanism were studied preliminarily.Lignite can be dehydrated effectively by extraction with acetone. The moisture content of XLHTL can be reduced from 20.4% to 3.5%, which meets to the needs to lignite processing and utilization. Meanwhile, some small fractions are extracted from the lignite with acetone.The XLHTL and HLGLL were extracted with carbon disulfide (CS2), n-hexane, benzene, ether, acetone, methanol and tetrahydrofuran (THF) sequentially. The results showed that extract yield of each stage are low which is related to metamorphic grade of lignite since its free small molecules are few whereas the reticular structures of macromolecular were compact. The reaction mixtures from XLHTL and HLGLL over alcoholysis reaction under supercritical condition were extracted with n-hexane, ether, methanol and THF sequentially. The extract yield went up sharply with a total extractability of above 80%. The components of the reaction mixture were analyzed by GC/MS and the detectable compounds were far more than those of extractions of each stage from raw coal, especially, many phenols were detected. The study took some factors which can effected the reaction into consideration, such as reaction temperature, reaction time, the ratio of alcohol and coal, the ratio of alkali and coal and different kinds of higher alcohol. Under the same conditions, the study on Shenfu coal and Tongting coal alcoholysis reaction were carried, the yieds were lower than those of XLHTL and HLGLL.The reaction mixtures were separated by column chromatography so as to get detail information about the components, obtained water-soluble compounds, alkanes, arenes and heteroatomic containing compounds and so on. The separation products were analyzed by GC/MS, The occurrence of alkanes, arenes and heteroatomic containing compounds were discussed . A series of carbonic esters and one pure component which was identified to be an fatty acid ester.The solid base catalysts CaO, K2CO3/γ-Al2O3, K2CO3/γ-Al2O3-NaOH and KF/γ-Al2O3 were prepared, characterized and applied in the lignite coal alcoholysis reactions, the yields were 88.2%,64.4%,73.9%和78.3%. The reaction mixture's component were same as those from methanol-alkali system.The reactions of methanol itself over CaO-catalyzed in supercritical condition were studied and analyzed the components of the products to deduce preliminarily the reaction mechanism. Diphenyl ether, benzyl phenyl ether (BPE), anisole, 2-ethoxynaphthalene, phenol, Resorcinol, benzene and anthracene as the model compounds were used to study the mechanism of reaction. The results show that the main reaction form is the fracture of ether linkage followed by hydrogenation, alkylation and methoxylation of aromatic ring.