Study On The Dissociation Law And Molecular Struc-Ture Of Sporinites In Datong Spore-rich Coal

Spore-rich coal is a special type of coal which is extremly scarce and rich spore bodies.There are currently few studies on Spore-rich coal,so it is of great significance to study the rule of decomposition and separation,and the characteristics of molecular structure of the spore-rich coal for its qualitative utilization.In this paper,based on the analysis properties and the maceral characteristics of raw coal of Yanzishan in Shanxi Datong,the dissociation and enrichment of different macerals,and the composition of small molecular compounds as well as the macromolecular structure characteristics of sporinites were systematically studied.The results of coal quality and reflectivity of the spore-rich coal show that it has the characteristics of high volatile and low thermal evolution;The breaking and screening spore-rich coal demonstrates that vitrinite content show a decrease gradually with an increase in crushing size,while the content of the inertinic group and the exinite group increase.The density gradient method shows that the density of the chitin group is mainly distributed below-1.25 g.cm-3.When the crush coal sample among 0.125 mm-0.074 mm and the separation density to 1.25 g.cm-3,the yield of the chitin group can be up to 89.93%.Separation of the enriched chitin group reveal that the sporinites were mainly concentrated among 1.16g.cm-3-1.18 g.cm-3,and the yield reached over 90%.The vitreous group is mainly distributed at 1.25 g.cm-3-1.37 g.cm-3,and the inert group is mainly distributed at 1.37 g.cm-3-1.45 g.cm-3.Using four different polar extraction agents of toluene,methanol,cyclohexane and tetrahydrofuran were used to extract small molecular compounds from sporinite by using ultrasonic-assisted extraction.The extraction rates of the four different extraction agents array from high to low:tetrahydrofuran,methanol,cyclohexane and toluene.Among them,the extract of methanol and tetrahydrofuran are mainly oxygenated compounds,and oxygenated compounds are mainly dominated by phthalates esters,and some alcohol compounds also exist Cyclohexane and toluene extracts are mainly aliphatic hydrocarbon compounds,and aliphatic hydrocarbon compounds are mainly normal paraffins.The FTIR of the extraction residue and sporinite shows that there is obvious change in the structure of functional groups before and after spore extraction.The intensity of the absorption peak of the extracted residue in the corresponding position is weakened.The structure parameters of sporinites were obtained by analyzing the results of the elemental analysis?FTIR?XPS and 13C NMR,and the planar structure model of sporinite was determined.The sporinite is mainly composed of aromatic structure and contain some aliphatic structures as well as oxygen-containing functional groups.The aromatic structure is mainly composed of 3 benzene rings and 3 naphthalene rings.the fat structure is mainly composed of alkyl side chains,and the oxygen atoms in sporinite include 1 phenolic hydroxyl,5 ester groups,3 carboxyl groups,3 ether oxygen groups and 1 carbonyl group.N elements mainly include two pyridine rings.The macromolecule structure of sporinite is constructed by Chemdraw software,the gNMR software was used to simulate the nuclear magnetic carbon spectrum,and simulated NMR carbon spectrum is compared with the experimental NMR carbon spectrum to determine the macromolecular planar structure of the sporinite,and its molecular formula is C113H134N2O21 and relative molecular weight is 1854.After the optimization of molecular mechanics,the valence electron energy and non-bonding energy of sporinite were decreased significantly by MS software,after the dynamic optimization simulation,it was found that the total energy decreased,the torsional energy and the bond angle energy increased,which the molecular structure and chemical bonds of the sporinites are significantly bent and twisted,which become a spatial structure with stable properties.By adding periodic boundary conditions to the sporinite minimum energy structure model of sporinite to analyze the relationship between spore energy and density.it is found that the spore model was more compact,the spatial sense was enhanced,the degree of distortion of the aromatic structure and fat chain were enhanced.The sporinite density was determined to be 1.16 g.cm-3,which was consistent with the experimental data.