1,3,5-三乙酰基六氢均三嗪分子的吸收光谱及合成反应热力学性质的理论研究

1,3,5-三乙酰基六氢均三嗪分子(TRAT)作为高能炸药的中间体,研究其光谱性质及合成反应热力学可能性具有较大学术意义.使用密度泛函理论B3LYP方法对合成TRAT反应的相关分子进行几何结构优化、不同温度下的热力学性质计算,用含时密度泛函理论TD-B3LYP方法计算TRAT的电子吸收光谱.结果显示,优化得到的TRAT分子稳定结构由3个面组成,气相中最低能量跃迁吸收峰出现在224 nm,属于近紫外区,溶剂作用使其蓝移5～6 nm,溶剂不影响跃迁性质.298.15 K与标准大气压下,TRAT分子的标准摩尔生成焓和标准摩尔生成自由能分别为-681.95和-361.31 kJ.mol-1.合成反应的标准摩尔生成焓变和标准摩尔生成自由能变分别为-132.01和-67.23 kJ.mol-1,合成反应在600 K以下能自发进行.

Theoretical Study on Absorption Spectra and Synthetic Reaction's Thermodynamic Properties of 1,3,5-Triacetyle-1,3,5-Triazacyclohexane

The study on the absorption spectrum and the possibility of synthetic reaction’s thermodynamic properties of 1,3,5-Triacetyle-1,3,5-triazacyclohexane(TRAT) is of great academic significance since TRAT is the intermediate of high explosive.Density functional theory with B3LYP method is applied to optimize the molecular structures in TRAT synthetic reaction and calculate the thermodynamic property at different temperatures,while time-dependent DFT is applied to electronic absorption spectrum.The result shows that the optimized stable TRAT molecule structure is composed of three sides.In gas,absorption wavelength of the lowest energy excitation is obtained at 224 nm in the near ultraviolet region and solvents can make it blue-shifted 5～6 nm,without effect on the nature of transition.The standard molar formed enthalpy and free energy of TRAT molecule are-681.95 and-361.31 kJ·mol-1 at 298.15 K,respectively.The standard molar formed enthalpy change and gibbs energy of this synthetic reaction are-132.01 and-67.23 kJ·mol-1,respectively,which indicates the reaction can carry out spontaneously at 600 K.