Study On Reaction Mechanism Of Antioxidant Inhibiting Coal Peroxyradical Based On Quantum Chemical

Low-rank coal is prone to spontaneous combustion in the process of storage,transportation and drying,which brings serious safety and economic problems to coal-related industries.Adding inhibitors is a common method to prevent and control spontaneous combustion of coal,but the general inhibitors have some problems such as low efficiency and short life.Therefore,it is of great theoretical and practical significance to develop environment-friendly and efficient inhibitors for the prevention and control of coal spontaneous combustion through the research of inhibition mechanism.This dissertation proposes a compound antioxidant enzyme inhibitor,mainly composed of polyethylene glycol-superoxide dismutase（PEG-SOD）and manganese catalase（Mn-CAT）,which is used to inhibit coal spontaneous combustion using quantum chemistry Method analysis.The charge distribution analysis,structural parameters and boundary orbit analysis of the SOD active center structure and the structure of coal peroxygen radicals was carried out,,which proved the existence of active sites.Model optimization,transition state calculation and IRC verification were carried out for the chemical adsorption and oxidation reaction processes involving ROO·in coal.Thermodynamic parameters were calculated and analyzed accordingly.The calculation results show that the chemical adsorption of O₂ on aliphatic hydrocarbon radicals produces ROO.This reaction is a zero-level barrier-free reaction and can be carried out at room temperature.Enthalpy becomes-132.64 k J/mol.The further reaction of ROO·is mainly carried out through H transfer between adjacent groups and within the group.SOD can carry out disproportionation reaction to eliminate ROO·,and the energy barrier is 31.3 k J/mol.This means that SOD should automatically eliminate ROO·at room temperature to inhibit low-temperature oxidation of coal.This dissertation conducts experimental research on raw coal and coal samples with compound antioxidant enzyme inhibitors.Through thermogravimetric-infrared experimental research,it is concluded that compared with raw coal samples,The mass gain stage of coal samples with compound inhibitors disappeared and the maximum heat release rate decreased,which confirmed that SOD could hinder the reaction between coal and oxygen;the electron paramagnetic resonance instrument is used to analyze the characteristic changes of free radicals in the oxidation process of coal,and the study found that the free radicals of coal samples are inhibited at the same temperature The content,g factor and line widthΔH are less than raw coal;XPS full-spectrum scanning is used to analyze the surface elements and relative content of coal samples.The study shows that as the temperature increases,the content of C-C/C-H functional groups in raw coal samples decreases and C-O The group content increases,the content of C=O/O-C-O and O=C-O groups does not change much below 90°C,and the gradual increase of C-C/C-H groups in the coal sample is inhibited,the content of C-O groups is significantly reduced,and C=O/O-C-O and O=C-O groups remain roughly unchanged.Our research results help to further understand the mechanism of ROO·participating in the reaction,and provide theoretical support for predicting the coal spontaneous combustion.