【摘要】 利用密度泛函理论(DFT)方法,以哒嗪为煤的模型化合物,在(U)B3LYP/6-31G(d,p)水平下计算了标题化合物的键布居数和键裂解能,并对其热解机理进行了探讨.在(U)B3LYP/6-311++G(d,p)水平下计算了热解过程中各物种的单点能,并对总能量进行了校正.结果表明,标题物N—N键的布居数和裂解能均最小,且各键裂解能随温度变化不大,热解最终产物为HCN和乙炔,NH3可能是HCN经过二次转换得到的.采用过渡态理论计算了300～1900 K温度范围内热解的速率常数,求得lnk与1/T的线性关系.更多还原

【Abstract】 The pyrolysis mechanism of nitrogen element in pyridazine as a model compound of coal was investigated by density functional theory（DFT） method.The Mülliken populations,bond dissociation enthalpies and pyrolysis mechanism of title compound were calculated under the（U）B3LYP/6-31G（d,p） level.The single-point energy calculations were performed under the（U）B3LYP/6-311++G（d,p） level for the stationary and transition state structures of pyrolysis processes with the zero-point energy correction.It is shown that the N_N bond has the least population and bond dissociation enthalpy and there is not significant change of the bond dissociation enthalpy for title compound with the temperature increased.The ultimate pyrolysis products are HCN and acetylene according to the calculations.It is proved that NH3 maybe the secondary conversion product of HCN.The rate constants are obtained via Eyring transition-state theory in temperature range of 300₁900 K,the linear relationship between lnk and 1/T is identified.更多还原