Seperation And Analysis Of Soluble Organic Matters In Soft Coal And Hard Coal From Cheji Coal Mine

Soft coal(SC)and hard coal(HC)from Cheji coal mine were selected as the coal samples.18 soluble portions(SPs)were obtained using ultrasonic extraction(UE),thermal dissolution(TD),and ultra-high pressure extraction(UHPE)with methanol(ME),toluene(TOL),and acetone(AC),respectively.Furthermore,structure information of these 18 SPs were compared and discussed with in-source collision activated dissociation(ISCAD)according to 22 model compounds.Finally,the high-performance liquid preparative chromatography(HPLPC)was introduced to further separate those SPs,and some fractions with higher purity were collected and characterized by gas chromatograthy/mass spectrometry(GC-MS)and orbitrap mass spectrometry(Orbitrap-MS).SPs from UHPE have relatively higher yields compared to TD and UE,and the residues present smoother surface according to the characterization of scanning electron microscope(SEM).It mostly because the solvent molecule can permeate into pore structure of coal and destroy its framework in the UHPE procedure.Hence,more organic components were extracted.By comparing with fragmentation patterns and pathways of 22 model compounds in the ISCAD experiment,three main results were concluded.Firstly,the crackings of aromatic cores mostly presented under energies over 80 eV,and more side chains connected to aromatic core higher collision energy was needed due to negative conjugation effect.Then,the cleavages of alkyl groups,bridged bonds,and side-chains containing heteroatoms often occurred under low energy region,and compounds containing longer bridged bonds or side chains will be easier cleaved.In addition,the releases of heteroatoms in the aromatic ring might be difficult and release order was sulfur < oxygen < nitrogen.For the ISCAD of SPs,SPs from TD distributed amount of small molecules with double bond equivalence(DBE)<10 and carbon number <15.Although SPs from UE had similar distribution,the number of identified compounds was fewer.Besides,SPs from UHPE contained many long-chain compounds with DBE <5 and carbon number >15.Among which the species of compounds extracted by ME and AC were significantly higher than TOL due to their smaller molecular volumes and higher polarities.Above results are crucially important for the modification research of polyurethane grouting material.1,2-diphenylethane and 1,2-diphenylethene with high purity were collected using HPLPC which can be used as medical intermediates.More important,a pair of cis-trans isomers of 1,2-diphenylethene were separated and identified by GC-MS.Above research provides theoretical basis for understanding the properties of SC and HC at the molecular level.