【作者】 郝朝瑜；

【导师】 王继仁；

【作者基本信息】 辽宁工程技术大学 ， 安全技术及工程， 2010， 博士

【摘要】 煤自燃不仅造成能源浪费与环境污染,而且严重影响着矿井的安全生产。阻化剂防止煤自燃是一种有效的方法。由于煤结构与组分的复杂性,预防煤炭自燃的阻化机理需要更为深入的研究。预防煤炭自燃的配位阻化理论是煤加入阻化剂后,煤中的活性基团与阻化剂中的金属离子形成了配合物,从而阻止了活性基团与氧的反应。本文在配位阻化理论的基础上,应用量子化学理论,研究了煤的芳香性、氢键的作用及溶剂化效应对配合物性质变化的影响,对钙基阻化剂与煤中含N活性结构形成配合物分子的几何特征、前线轨道、相互作用能、净电荷布居以及光谱特征等进行了研究。本研究成果是对配位阻化理论的创新与完善。研究了煤含N特征结构中芳香性的增加对形成配合物的影响。采用密度泛函在B3LYP/6-311G*水平上计算发现,随着芳香性的增加,N-Ca-O键角增大,Ca-N配位键的键长缩短,Ca-O配位键的键长伸长。当苯环数增加到四个时,形成了Ca-N-C-O四元环状结构。煤活性结构与Ca²⁺形成的配位化合物的能隙逐渐增大,配合物的相互作用能逐渐降低,形成配合物的稳定性逐渐增大。配位键Ca-O的伸缩振动峰未发生偏移,而配位键Ca-N的伸缩振动峰发生了大幅蓝移,说明煤活性基团的芳香性对配位键Ca-N的影响很大,配合物的稳定性大增。阻化剂的阻化效果随着煤特征结构芳香性的增大而提高。研究了氢键对形成配合物的作用。采用密度泛函理论在B3LYP/6-311G*水平上对H₂O参与形成配合物的过程进行优化计算,结果显示H₂O首先通过氢键的分子识别与引导作用与Ca²⁺的配体-OH相互作用,进而再与Ca²⁺相互作用形成配合物。在整个过程中,氢键能一直保持并形成分子内Ca-O-H-O四元环结构,配合物的稳定性得到大幅提高。有H₂O参与配位后配合物分子的前线轨道能级和相互作用能降低,稳定性增加。一个H₂O参与配位后Ca仍偏离其表观电荷,还可继续形成配位键。有H₂O参与配位分子内形成Ca-O-H-O四元环结构,煤的芳香性对配位键Ca-N的影响降低。溶剂通过氢键参与配位,阻化剂的阻化效果倍增。研究了溶剂化效应对形成Ca²⁺阻化剂配合物的影响。运用极化连续介质模型（PCM）研究了溶剂化效应对形成配合物的影响。结果显示配合物在液相环境下分子的构象发生变化,溶液中配合物的HOMO轨道的构成由Ca和N转移都苯环和侧链的C上,Ca-N配位键加强,N的活性降低。前线轨道的能量差,净电荷布居都显示配合物稳定性增加。说明配合物受溶剂化效应影响稳定性更强,阻化剂的阻化效果更好。本文从微观上揭示了溶剂对阻化剂阻化效果起到的重要作用,阐述了阻化剂防火中溶剂选择的必要性,是预防煤炭自燃的配位阻化理论的创新与完善。更多还原

【Abstract】 Coal spontaneous combustion cause energy dissipation and environmental pollution, as well as serious problems on production security of coal mine. The use of retardant has been an effective method in preventing coal spontaneous combustion. Due to the complexity of coal structure and component, thoroughly research on mechanism of inhibition of coal spontaneous combustion is needed. Theory of coordinate inhibition in preventing coal spontaneous combustion means that in the presence of retardant, the active groups of coal forms complex with metal ions in retardant so as to prevent their reaction with oxygen. This thesis based on theory of coordinate inhibition, utilized quantum chemistry theory, studied coal aromaticity, hydrogen bond and sovation effect which affected the complex properties. The geometrical characteristics, frontier molecular orbital, net charge population, spectrum characteristics and binding energy of the complex between N containing active structures in coal and calcium based retardant were investigated. The research achievements are creation and improvement on theory of coordinate inhibition.Affects on forming complex according to the increasing aromaticity of N containing characteristic structures in coal were studied. An increase of N-Ca-O bond angel, a decrese of Ca-N coordination bond legth and an increase of Ca-O coordination bond legth were noticed along with the increase of aromaticity during calculation on B3LYP/6-311G* level adoping density functional theory. Ca-N-C-O four member ring structure was formed when the number of benzene ring rose to four. The energy gap of complex between Ca²⁺ and active structure of coal increase gradually, the total energy of complex system decrease gradually, and the stability of complex so formed increase gradually. There was no noticeable shift of stretching vibration peak of the coordination bond Ca-O, on the contrary large blue shift was observed of stretching vibration peak of the coordination bond Ca-N. This indicated that large effect on coordination bond Ca-N by the aromaticity of the active group of coal, and more stability of the complex. It is found that the larger the aromaticity of the charictristic sturcture of coal, the more efficent of retardant’s inhibition effect.Effect of hydrogen bond on forming complex was studied. Optimized calculation of the process of coordination in the presence of H₂O was carried on B3LYP/6-311G* level adoping density functional theory. Result showed that H₂O first react with the ligand–OH of Ca²⁺ through molecular recognition and molecular guide of hydrogen bond, and further react with Ca²⁺ to form complex. Hydrogen bond always maintained and helped to form intramolecular Ca-O-H-O four member ring structure, which largely increased the stability of complex. The enegy level of frontier molecular orbital and system energy of complex decreased which result in more stability. Ca still diverge its apparent charge after one H₂O molecule coordinated so as it can keep on forming more coordination bond. The intramolecular Ca-O-H-O four member ring structure formed in the presence of H₂O, and the effect of aromaticity of coal on coordination bond Ca-N decresed. The inhibition effect largely increased when solvent coordinated through hydrogen bond.Affect on Ca²⁺ retardant complex forming by effect of salvation was sturdied. Affect on complex forming by effect of salvation was sturdied by polarizable continuum model（PCM）. Result showed that molecular conformation changed on liquid phase, the composition of HOMO orbital of complex in solution shifted to benzene ring and C of side chain from Ca and N, result in enhancement of Ca-N coordination bond as well as less activity of N. Energy difference frontier molecular orbital and net charge population indicated that more stability of complex. It suggested that complex more stable in aqueoue solution and better inhibition effect of retardant.Extreme effect of solvent on inhibition effect of retardant was showed on microcosmic, the necessarity in the need for solvent selection during the configuration retardant process was illustrated, and creation and improvement on theory of coordinate inhibition were achieved in this thesis.更多还原