硝基胍溶液的热分解性能及动力学

硝基胍(NQ)在进行运输和储存时,通常采用水作稳定剂。为研究硝基胍加水后的热分解行为,借助差示扫描量热仪(DSC)研究了其在动态和等温条件下的分解情况。结果表明,硝基胍溶液在动态和等温模式下均显示一个放热峰,其平均比放热量分别为311 J·g~(-1)和305 J·g~(-1)。基于Friedman法计算得知动态模式下的活化能为84~78 kJ·mol~(-1),等温模式下活化能为86~78 kJ·mol~(-1),且数值变动很小;表明其热解过程可用单步机理描述。根据等温模式下的钟型放热速率曲线,判断其热分解属于单步自催化机理;进而采用包含引发反应的自催化模型,对等温数据进行非线性拟合得到了其分解反应速率表达式,且自催化机理的计算结果与动态DSC的实测数据一致性好,证明该模型可靠。

Thermal Decomposition Characteristic and Kinetics of Nitroguanidine Solution

Nitroguanidine(NQ) is usually suggested add water as stabilizer before transport and storage.To investigate the thermal decomposition characteristic of the mixture,differential scanning calorimetry (DSC) was used to test the thermal decomposition behaviors of NQ under dynamic and isothermal conditions.The specific heat generation of the decomposition reaction were about 311 and 305 J · g-1 for dynamic and isothermal DSC.The activation energy of NQ solution under dynamic DSC (Eα =84-78 kJ · mol-1)and isothermal DSC(Eα =86-78 kJ · mol-1) obtained by Friedman method was very close,and the value of it did not show much variation;indicated the reaction could be expressed as single step mechanism.And the bell-shaped curves under isothermal DSC indicated the autocatalytic character of it.Then a more accurate autocatalytic model was chosen to describe it,nonlinear fitting was used to calculate the kinetic parameters,the model function equation was expressed as dα/dt=exp (18.03) exp (-92170/RT) (1-α) 1.1u +exp (18.00) exp (-76400/RT) (1-α)1.111α1.995.And the dynamic data well fitted with the model curves,verified the correctness of the single autocatalytic model.