Preparation Of A Magnetic Solid Superbasecatalyst And Application For Huolinguole Lignite Hydrocracking

Hydrocracking was an important reaction for direct coal liquefaction. Preparing appropriate catalysts was the core technology in the hydrocracking process. The new magnetic solid superbase(MSSB) catalyst was prepared as follows: Fe3O4 was prepared by using chemical precipitation, then the modified Fe3O4 nanoparticles were coated with a film of Si O2, and then impregnated Mg2 Si by electroless deposition.The samples were determined by means of TEM, HRTEM, EDX, XRD, CO2-TPD, BET and VSM, the analyses revealed that the MSSB had large specific surface area, mesoporous structure, superparamagnetism, recycle and high strength alkali. Benzyloxybenzene(BOB) was used as a coal-related model compound to evaluate the catalytic activity. BOB conversion and products yields obviously increased with the increases in the reaction temperature, reaction time and MSSB feed, but initial hydrogen pressure is insignificant.The Huolinguole lignite(HL) was subjected to non-catalytic hydrocracking and catalytic hydrocracking over MSSB in cyclohexane, methanol, ethanol and isopropanol under pressurized hydrogen at 300 oC, in sequence. The reaction mixtures were analyzed with a gas chromatography/mass spectrometer(GC/MS). The analysis results revealed that MSSB catalyst can release small molecular mass components and effectively enhance the contents of aromatics and phenols.The reactions of several coal relative model compounds showed that carbonoxygen(C-O) bond in BOB, 1-MON and DBE can be specifically cleaved over the MSSB. Strong alkali of the MSSB facilitated heterolytical splitting of H2 to an immobile H+ adhered to the MSSB surface and a mobile H-. The mobile H- added to the ipso-position of aryl ether to lead the cleavage of C-O bond. The generation of Hwas the key step of the hydrocracking reactions. Herein the reaction mechanism of coal hydrocracking was derived from the reaction of the model compounds.