Estimation of Critical Temperature of Thermal Explosion for Nitrosubstituted Azetidines Using Non-isothermal DSC

Based on reasonable hypothesis, two general expressions and their six derived formulae for estimating the critical temperature (T_b) of thermal explosion for energetic materials (EM) were derived from the Semenov's thermal explosion theory and eight non‐isothermal kinetic equations. We can easily obtain the values of the initial temperature (T_0i) at which DSC curve deviates from the baseline of the non‐isothermal DSC curve of EM, the onset temperature (T_ei), the exothermic decomposition reaction kinetic parameters and the values of T₀₀ and T_e0 from the equation T_{0i or ei}=T_{00 or e0}+a₁β_i+a₂β_i²+···+a_L?2β_i^L?2, i=1, 2, ;···, L and then calculate the values of T_b by the six derived formulae. The T_b values for seven nitrosubstituted azetidines, 3,3‐dinitroazetidinium nitrate ( 1 ), 3,3‐dinitroazetidinium picrate ( 2 ), 3,3‐dinitroazetidinium‐3‐nitro‐1,2,4‐triazol‐5‐onate ( 3 ), 1,3‐bis(3′,3′‐dinitroazetidine group)‐2,2‐dinitropropane ( 4 ), 1‐(2′,2′,2′‐trinitroethyl)‐3,3‐dinitroazetidine ( 5 ), 3,3‐dinitroazetidinium perchlorate ( 6 ) and 1‐(3′,3′‐dinitroazetidineyl)‐2,2‐dinitropropane ( 7 ), obtained with the six derived formulae are agreeable to each other, whose differences are within 1.5%. The results indicate that the heat‐resistance stability of the seven nitrosubstituted azetidines decreases in the order 6 > 7 > 5 > 4 > 3 > 2 > 1 .     

Estimation of the Critical Temperature of Thermal Explosion for the Highly Nitrated Nitrocellulose Using Non-isothermal DSC

Two methods for estimating the critical temperature (T_b) of thermal explosion for the highly nitrated nitrocellulose (HNNC) are derived from the Semenov's thermal explosion theory and two non-isothermal kinetic equations, d/dt=Af()e^–E/RT and d/dt=Af()[1+E/(RT)(1–T_o/T)]e^–E/RT, using reasonable hypotheses. We can easily obtain the values of the thermal decomposition activation energy (E), the onset temperature (T_e) and the initial temperature (T_o) at which DSC curve deviates from the baseline of the non-isothermal DSC curve of HNNC, and then calculate the critical temperature (T_b) of thermal explosion by the two derived formulae. The results obtained with the two methods for HNNC are in agreement to each other.This revised version was published online in November 2005 with corrections to the Cover Date.     

Estimation of Critical Rate of Temperature Rise for Thermal Explosion of First Order Autocatalytic Decomposition Reaction Systems by Using Non-isothermal DSC

A method of estimating the critical rate of temperature rise for the thermal explosion of first order autocatalytic decomposition reaction systems by using non-isothermal DSC is presented. The information was obtained on the increasing rate of temperature for the first order autocatalytic decomposition of nitrocellulose containing 13.86% nitrogen converting into the thermal explosion.     

用非等温DSC基于Harcourt-Esson方程估算含能材料热爆炸临界温度的一种简单方法

用合理假设,由Semenov热爆炸理论和基于Harcourt-Esson速率表达式非等温动力学方程 ,推导了估算含能材料热爆炸临界温度的一种简单方法。该计算式为 ,比较简单。从非等温DSC曲线上onset温度（ ）通过表达式 可得到 ,由方程 可求得 值,随后算出 。该方法计算结果与Zhang-Hu-Xie-Li方法结果相一致。     

从DSC曲线数据计算/确定含能材料自催化分解反应动力学参数和热爆炸临界温升速率的方法

为应用热爆炸临界温升速率(dT/dt)_Tb评价含能材料(EMs)的热安全性, 得到计算(dT/dt)_Tb值的基本数据, 用合理的假设, 由Semenov的热爆炸理论和9 个自催化反应速率方程[dα/dt=Aexp(-E/RT)α(1-α) (I), dα/dt=Aexp(-E/RT)(1-α)ⁿ(1+K_catα) (II), dα/dt=Aexp(-E/RT)[α^a-(1-α)ⁿ)] (III), dα/dt=A₁exp(-E_a1/RT)(1-α)+A₂exp(-E_a2/RT)α(1-α) (IV), dα/dt=A₁exp(-E_a1/RT)(1-α)^m+A₂exp(-E_a2/RT)αⁿ(1-α)^p (V), dα/dt=Aexp(-E/RT)(1-α) (VI), dα/dt=Aexp(-E/RT)(1-α)ⁿ (VII), dα/dt=A₁exp(-E_a1/RT)+A₂exp(-E_a2/RT)(1-α) (VII), dα/dt=A₁exp(-E_a1/RT)+A₂exp(-E_a2/RT)α(1-α) (IX)]导出了计算(dT/dt)_Tb值的9 个表达式. 提出了从不同恒速升温速率(β)条件下的差示扫描量热(DSC)曲线数据计算/确定EMs自催化分解反应的动力学参数和自催化分解转向热爆炸时的(dT/dt)_Tb的方法. 由DSC曲线数据的分析得到了用于计算(dT/dt)_Tb值的β→0 时的onset 温度(T_e0),热爆炸临界温度(T_b)和相应于T_b时的转化率(α_b). 分别用线性最小二乘法和信赖域方法得到方程(I)和(VI)及方程(II)-(V)和方程(VII)-(IX)中的自催化分解反应动力学参数. 用上述基础数据得到了EMs的(dT/dt)_Tb值. 结果表明: (1) 在非等温DSC条件下硝化棉(NC, 13.54% N)分解反应可用表观经验级数自催化反应速率方程dα/dt=10^15.82exp(-170020/RT)(1-α)^1.11+10^15.82exp(-157140/RT)α^1.51(1-α)^2.51描述; (2) NC (13.54% N)自催化分解转向热爆炸时的(dT/dt)_Tb值为0.103 K·s^-1.     

2-羟基和4-羟基-3,5-二硝基吡啶铅盐的热行为、分解机理、非等温分解反应动力学及其在推进剂中的应用

在程序升温条件下 ,用DSC ,TG ,慢速裂解 /傅里叶红外 ,研究了 2 羟基 3 ,5 二硝基吡啶铅盐 ( 2HDNPPb)和 4 羟基 3 ,5 二硝基吡啶铅盐 ( 4HDNPPb)的热行为、机理和动力学参数 ,提出了它们的热分解机理 ,计算了热爆炸临界温度 ,考察了它们对RDX改性双基推进剂的催化效果 .结果表明 :2HDNPPb和 4HDNPPb主放热分解反应的表观活化能和指前因子值分别为 2 5 2 .3 4kJ·mol-1,10 19.3 0 s-1和 187.3 9kJ·mol-1,10 13 .74s-1.由加热速率 β→ 0的DSC曲线的初始温度 (Te)和峰温 (Tp)算得 2HDNPPb和 4HDNPPb的热爆炸临界温度值分别为 3 2 7.64 ,3 3 6.5 7和 3 2 3 .90 ,3 3 3 .96℃ .2HDNPPb的热稳定性优于4HDNPPb .0 .1MPa时 ,它们的放热分解过程动力学方程可表示为 :　　对 2HDNPPb　　dα/dT =10 2 0 .48( 1-α) [-ln( 1-α) ] 3 /5e-3 .0 3 51× 10 4 /T　　对 4HDNPPb　　dα/dT =10 15.0 0 ( 1-α) [-ln( 1-α) ] 2 /3 e-2 .2 53 9× 10 4 /T对含RDX改性双基推进剂 ,它们都具有催化燃烧和降低压力指数的作用 .2HDNPPb的催化效果明显优于 4HDNPPb .羟基在分子中所处的不同位置是影响热稳定性和催化效果的主要因素     

用非等温DSC估算3,4-双(4’-硝基呋咱-3’-基)-2-氧化呋咱(BNFOF)放热自催化分解反应的热爆炸临界温升速率和动力学参数

A method of estimating the kinetic parameters and the critical rate of temperature rise in the thermal explosion for the autocatalytic decomposition of 3,4-bis（4＇-nitrofurazan-3＇-yl）-2-oxofurazan （BNFOF） with non-isothermal differential scanning calorimetry （DSC） was presented. The rate equation for the decomposition of BNFOF was cstablished, and information was obtained on the rate of temperature increase in BNFOF when the empiric-order autocatalytic decomposition was converted into thermal explosion.