Compositional Analysis And Catalytic Hydrogenation Of Coal Liquefaction Residues

Investigating the compositions and structures in soluble organic matter from coalliquefaction residue is of great significance for both targeted conversion and efficientutilization of coal liquefaction residue. In order to investigate the organic chemicalcompositions of coal liquefaction residue, Heishan coal liquefaction residue （HSR） and Shenglicoal liquefaction residue （SLR） were selected in this subject. HSR and SLR were extractedwith petroleum ether, methanol, cyclohexane, CS₂, benzene and acetone/CS₂（1:1, V/V）sequentially and the extracts were analyzed with GC/MS. The results shows that theGC/MS-detectable species can be classified into normal alkanes, branched alkanes, alkenes,arenes, hydroxybenzenes, esters, ketones, alcohols and other species organic compounds. Thenumber of GC/MS-detectable compounds in extracts of petroleum ether, methanol andcyclohexane were appreciably more than those in extracts of CS₂, benzene and acetone/CS₂.HSR, SLR, their extracts and extraction residues （acetone/CS₂-insoluble） were subject toruthenium ion-catalyzed oxidation （RICO）. After esterification with diazomethane, theproducts were analyzed with FTIR and GC/MS. The results show that main component in theproduct from HSR is benzene carboxylic acids, however, short-chain alkanedioic acids are themost abundant species in the product from SLR, implying that HSR contains large amounts ofcondensed polyaromatic rings, and SLR contains more-diarylalkanes. The lengths ofcarbon chain of monocarboxylic acids and dicarboxylic acids are short, suggesting that theresidues are rich in condensed aromatic rings and the condensed aromatic species are insolubleand inactive toward hydroliquefaction, whereas alkylarenes and-diarylalkanes with longchain are soluble and active components toward hydroliquefaction. A series of alkanes,distribution of carbon atoms in C13-C20, were only detected in the oxidation products fromextraction residue of HSR and SLR. The yields of halogenated alkanes, ethoxy alkanes andshort chain ketones in the products from RICO of extraction residues of HSR and SLR weresignificantly higher than those from RICO of HSR and SLR.The further separation of CS₂-extractable fraction of SLR by silica-gel columnchromatography achieved five group fractions, including alkanes, arenes （three） and esters.This result demonstrates that solvent extraction combined with column chromatography hasgood separation effect on the organic matter of coal liquefaction residue. This method canprovide more information of the compositions and structures of organic macromolecularcomponents in coal liquefaction residue and reliable theoretical basis for efficient utilization ofcoal liquefaction residue. Demineralized HSR and SLR were subject to hydroconversion in methanol undermicrowave irradiation followed by products analysis with GC/MS. The results show thatPd/γ-Al2O3possesses good hydrogenation activity and can promote hydroconversion of coalliquefaction residue effectively; The products of hydrogenation reactions from HSR and SLRcan be classified as alkanes, hydroarenes （HAs）, substituted arenes （SAs）, non-substitutedarenes （NSAs）, oxygen-containing organic compounds （OCOCs）, and sulfur-containingorganic compounds （SCOCs）. The yields of HAs, SAs and NSAs of products from catalytichydrogenations were significantly higher than those from non-catalytic hydrogenations.