The choice of pyrrole- and pyridine-containing nitrogen heterocycles as the subject of this paper is made in,and based on this,the mechanism and pattern of action of the influence of functional groups on the migration and transformation of nitrogen components ofcoal pyrolysis are studied. First,the CBS-QB3 is used to optimize the paths of pyrrole and pyridine pyrolysis to HCN and NH3,and thecorresponding reaction potential energy surfaces are derived. Additionally,the accumulated 112 nitrogen migration conversion pathwaysof pyrrole and pyridine derivatives are optimized, the functional groups are divided into electron-donating (EDG) and electron-withdrawing groups (EWG),and the summation values of the bond polarity indices of the groups are calculated based on Paulingelectronegativity. Finally,12 appropriate descriptors are screened by comparing Pearson correlation coefficients,which are derived fromthe structures effectively optimized by DFT calculations. By integrating multiple linear regression models,the greatest response activationenergy in the coal-nitrogen migration conversion process is predicted,and the MLR model constructed has a coefficient of determinationof 0.83,a root mean square error of 0.41 for the training set and a coefficient of determination of 0.92 and a root mean square error of 0.29for the test set. The model may be used to estimate activation energy since it has high fitting and prediction ability. An in-depth analysis of the multiple linear regression equation of the model reveals that the coefficient of the group type is the largest (0.71),followed by theenergy gap of the reactants (0.64) and the difference between the energy gaps of the reactants and products (-0.59), furtherconfirming the significant influence of the group type on the nitrogen migration transformation. The findings of this paper can guide themechanistic study of coal nitrogen migration conversion and aid in the creation of new ultra-low NOx combustion technologies.

王欣(1999-),女,山东菏泽人,硕士研究生。E-mail:wx_20191203@sjtu.edu.cn

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WANG Xin,ZHANG Hai,WANG Kai,et al. Mechanistic study of the effect of differential electron density characteristic groups on the nitrogen migration transformation in coal[J].Clean Coal Technology,2024,30(11):24−32.