Preparation Of Magnetic Solid Acid And Its Catalytic Cleavage Of Bridge-bonds In Organic Matter Of Xilinhaote Lignite

Coal is non-renewable,thus the efficient use of coal plays an important role for economic development in China.The liquefaction is a valid process for efficient utilization of coal in which the high active catalysts are critical.In this paper,two types of solid superacids TFOH/SiO2/Fe3O4(MTFOH)and Zr(SO4)2-TFOH/SiO2/Fe3O4(ZMTFOH)were prepared by loading active components trifluoromethanesulfonic acid(TFOH)and Zr(SO4)2-TFOH on SiO2/Fe3O4 support.These two catalysts were used to catalyze the cleavage reactions of the model compounds,naphthalene methane(DNM)and dibenzyl ether(DBE)as well as Xilinhot lignite(XHL)and extraction residues(XHEC),and the catalytical activities were investigated and the reaction products were analyzed.Firstly,the support was prepared and FeSO4· 7H2O was used as the iron source.The nano-Fe3O4 magnetic particles were prepared by co-precipitation method.Then SiO2/Fe3O4 magnetic support were prepared through the hydrolysis of tetraethyl orthosilicate to form SiO2 layer under alkalines condition.In the solvent of toluene,the support and active components(TFOH and Zr(SO4)2-TFOH)were added to prepare the magnetic catalysts under nitrogen.After characterizations,it was found that the prepared support was pure and the active components were better loaded on the support and the catalysts exhibited high acidity.Secondly,DBE and DNM were used as model compounds of coal.Under different conditions,the effects of catalysts on the conversions of 1 mmol model compounds are investigated.The mechanisms of the catalytical cracking of DBE and DNM are discussed.The results showed that both C-C bonds of DBE and C-O bonds of DNM undergo an effective cleavage reaction over these two catalysts,and specialy ZMTFOH can catalyze the cleavage of DBE and DNM at a temperature as low as 170? and 275?.Speculation 1 g coal,the reaction condition is at a temperature of 300?,reaction time of 4 h and catalyst dosage of 0.3 g.Finally,the cleavage reactions of XHL and XHEC were carried out,and the products were analyzed by gas chromatography-mass spectrometry.The results showed that under the catalysts of MTFOH and ZMTFOH,the yield of XHL reaction products was 16.8%and 23.1%higher than without catalysts;and the yield of XHEC reaction products was 30%and 33.6%higher than without catalysts;and the aromatic compounds was 5.6%and 10.1%higher than without catalysts.These indicate that the prepared catalysts can effectively fracture bridge bond in the organic matter of coal and have a significant effect on the cracking of XHL and XHE.This study provides a technical support for the efficient use of coal.