Search

The thermal decomposition behaviors of 1,3-di (azido-acetoxy)-2-methyl-2-nitropropane (DAMNP) under pressures of 0.1 MPa and 3.0 MPa were investigated by DSC techniques. The results showed that with the increase in pressure, the decomposition heat increased significantly, while the peak temperature increased slightly. The kinetic and thermodynamic parameters of exothermic decomposition reaction were obtained, and the iso-kinetic point was found as 192.0 °C. Using the thermal decomposition parameters, the self-accelerating decomposition temperature and the critical temperature of thermal explosion were calculated to be 190.10 °C and 202.58 °C, respectively. The specific heat capacity of DAMNP was studied with micro-DSC method, and the molar heat capacity was found to be 531.98 J mol−1 K−1. The adiabatic time-to-explosion was calculated to be 75.67 s. The combustion heat of DAMNP was determined with an oxygen bomb calorimeter, and the standard molar enthalpy of formation was calculated to be − 189.46 kJ mol−1. These results are important in evaluating the thermal stability and application prospects of DAMNP. [ABSTRACT FROM AUTHOR]

The dissolution properties of 2-oxo-1,3,5-trinitro-1,3,5-triazacyclohexane (Keto-RDX) in dimethyl sulfoxide (DMSO) were studied by using a RD496-2000 Calvet microcalorimeter at four different temperatures under atmospheric pressure. The heat effects, molar enthalpies (ΔdissH), and differential enthalpies (ΔdifH) of dissolution were determined. Furthermore, the corresponding kinetic equations describing the dissolution processes at the four experimental temperatures are dα/dt = 10−2.43 (1 − α)0.63 (T = 298.15 K), dα/dt = 10−2.41 (1 − α)0.67 (T = 303.15 K), dα/dt = 10−2.40 (1 − α)0.75 (T = 308.15 K), and dα/dt = 10−2.38 (1 − α)0.76 (T = 313.15 K). The determined values of the activation energy E and pre-exponential factor A for the dissolution process are 5.99 kJ mol−1 and 10−1.38 s−1, respectively. [ABSTRACT FROM AUTHOR]

The molar enthalpies of dissolution for potassium salt of bis(dinitromethyl)difurazanyl ether [K(BDFE)] in N-methyl-2-pyrrolidone (NMP) and water were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure. Empirical formulae for the calculation of the molar enthalpies of dissolution (Δ H), relative partial molar enthalpies (Δ H), and relative apparent molar enthalpies (Δ H) were obtained from the experimental data of the dissolution processes of K(BDFE) in NMP or water. Furthermore, the corresponding kinetic equations describing the two dissolution processes were d α/d t = 10(1 − α) for the dissolution of K(BDFE) in NMP and d α/d t = 10(1 − α) for the dissolution of K(BDFE) in water. [ABSTRACT FROM AUTHOR]

The dissolution properties of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowutrzitane (TEX) in N-methyl pyrrolidone (NMP) were studied with a RD496-2000 Calvet microcalorimeter at four different temperatures. The heat effects were measured for TEX in NMP. The molar enthalpies and the differential molar enthalpies for TEX in NMP were also obtained at the same time. The corresponding kinetic equations that describe the four dissolution processes are d α/d t = 10(1− α) ( T = 298.15 K), d α/d t = 10(1− α) ( T = 303.15 K), d α/d t = 10(1− α) ( T = 308.15 K), d α/d t = 10(1− α) ( T = 313.15 K), and respectively. The values of activation energy E and pre-exponential factor A for TEX in the dissolution process are 16.84 kJ mol and 10 s. [ABSTRACT FROM AUTHOR]

The thermal decomposition behaviors of dihydroxylammonium 5,5′-bistetrazole-1,1′- diolate (TKX-50) were studied by using a C-500 type Calvet microcalorimeter at five heating rates. The kinetic and thermodynamic parameters of the first decomposition reaction were obtained. The specific heat capacity of TKX-50 was determined with a Micro-DSCIII calorimeter, and the specific heat capacity equation and the molar specific heat capacity at 298.15 K were also obtained. The self-accelerating decomposition temperature and the critical temperature of thermal explosion are 466.17 and 475.36 K, respectively. The adiabatic time-to-explosion is calculated to be a certain value between 112.65 and 113.93 s. [ABSTRACT FROM AUTHOR]

The thermal decomposition behaviors of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowutrzitane (TEX) were studied by using a C-500 type Calvet microcalorimeter at five heating rates. The kinetic and thermodynamic parameters of exothermic decomposition reaction were obtained. The specific heat capacity of TEX was determined with a Micro-DSC III calorimeter, the specific heat capacity equation and the molar specific heat capacity were also obtained. The self-accelerating decomposition temperature, adiabatic decomposition temperature rise, and critical temperature of thermal explosion are 512.69, 7115.59, and 527.42 K, respectively. The adiabatic time-to-explosion is calculated to be a certain value between 53.69 and 54.05 s. [ABSTRACT FROM AUTHOR]

The thermochemical properties of 2,4-dinitroanisole (DNAN) in N-methy pyrrolidone (NMP) and dimethyl sulfoxide(DMSO) were studied using a RD496-2000 Calvet microcalorimeter at four different temperatures. The heat effects were measured for DNAN dissolved in NMP and DMSO and the relationships between the heat effects and the amounts of the substance were determined. The molar enthalpies and the differential molar enthalpies of dissolution processes were also obtained from the experimental data. The corresponding kinetic equations describing the two dissolution processes at different temperatures were discussed. [ABSTRACT FROM AUTHOR]

The dissolution properties of ammonium dinitramide (ADN) in N-methyl pyrrolidone (NMP) were studied with a RD496-2000 Calvet microcalorimeter at four different temperatures under atmospheric pressure. The heat effects were determined for ADN in NMP. The molar enthalpies and the differential molar enthalpies for ADN in NMP were also obtained at the same time. The corresponding kinetic equations that describe the four dissolution processes are discussed. [ABSTRACT FROM AUTHOR]

The high nitrogen compound 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine and the high energy density material hexanitrohexaazaisowurtzitane (HNIW), were used as substitute of hexogen (RDX) in the composite modified double base (CMDB) propellant formulations, the propellant samples were prepared, the thermal behaviors, nonisothermal reaction kinetics, and thermal safety were carried out, and the eight important parameters were calculated and obtained as the self-accelerating decomposition temperature ( T), thermal ignition temperature ( T), critical temperatures of thermal explosion ( T), critical temperature of hot-spot initiation ( T), characteristic drop height of impact sensitivity ( H), critical thermal explosion ambient temperature ( T), safety degree ( S), and thermal explosion probability ( P). It shows that the content of HNIW has a large effect on the decomposition reaction mechanism of the CMDB propellant, when the content of HNIW is 10 %, the decomposition reaction are controlled by the random nucleation and subsequent growth ( n = l), and the reaction mechanism obeys Mampel law; but when the content of HNIW is 20 %, the decomposition reaction are controlled by the chemical reaction ( n = 1/4). The mechanism can not be changed by the catalysts, and they just make the apparent activation energy change slightly. For the sample, from BC01 to BC04, the values of T and T making an upward tendency, show the resistivity to heat: BC04 > BC03 > BC02 > BC01; the values of T and S, BC01 are the maximum and BC02 are the minimum, show the heat sensitivity: BC01 > BC03 > BC04 > BC02. For the same radius, the thermal safety of the sphere sample is greater than that of the infinite cylinder one. [ABSTRACT FROM AUTHOR]

The enthalpy of dissolution of FOX-12 in dimethyl sulfoxide (DMSO) was measured by means of a RD496-III Calvet microcalorimeter at 298.15 K. Empirical formulae for the calculation of the enthalpy of dissolution ( $$ \Updelta_{\text{diss}} H $$ ), relative partial molar enthalpy ( $$ \Updelta_{\text{diss}} H_{\text{partial}} $$ ), and relative apparent molar enthalpy ( $$ \Updelta_{\text{diss}} H_{\text{apparent}} $$ ) were obtained from the experimental data of the enthalpies of dissolution of FOX-12 in DMSO. The kinetic equation that describes the dissolution process of FOX-12 in DMSO at 298.15 K is determined as $$ \frac{{{\text{d}}\alpha }}{{{\text{d}}t}} = 8.5 \times 10^{ - 3} (1 - \alpha )^{0.59} $$ . [ABSTRACT FROM AUTHOR]

1,3-Bis(4-aminophenoxy)benzene (TPER) and poly(amic acid) based on TPER and pyromellitic dianhydride (PMDA) were synthesized. After imidization of the poly(amic acid), polyimide based on TPER and PMDA was obtained. The melting process and the specific heat capacity ( C) of TPER were examined by DSC and microcalorimetry, respectively. The melting enthalpy, the melting entropy, and the C for TPER were obtained. The enthalpy change, the entropy change, and the Gibbs free energy change for TPER were obtained within 283 and 353 K. The thermal decomposition reaction mechanism of the polyimide is classified from the TG-DTG experimental data, and the thermokinetic parameters of the thermal decomposition reaction are E = 296.87 kJ moland log ( A/s) = 14.41. [ABSTRACT FROM AUTHOR]

The enthalpies of dissolution for Hydrazinium Dipicrylamine (HDPA) in N-methyl pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K. Empirical formulae for the calculation of the enthalpies of dissolution (Δ H) were obtained from the experimental data of the dissolution processes of HDPA in NMP and DMSO. The linear relationships between the rate ( k) and the amount of substance ( a) were found. The corresponding kinetic equations describing the two dissolution processes were $$ {{\text{d}\alpha } \mathord{\left/ {\vphantom {{\text{d}\alpha} {\text{d}t}}} \right. \kern-0pt} {\text{d}t}} = 10^{ - 2.71}\left( {1 - \alpha } \right)^{1.23} $$ for the dissolution of HDPA in NMP, and $$ {{\text{d}\alpha } \mathord{\left/ {\vphantom {{\text{d}\alpha} {\text{d}t}}} \right. \kern-0pt} {\text{d}t}} = 10^{ - 2.58}\left( {1 - \alpha } \right)^{0.81} $$ for the dissolution of HDPA in DMSO, respectively. [ABSTRACT FROM AUTHOR]

The thermal decomposition behavior of composite modified double-base propellant containing hexanitrohexaazaisowurtzitane (CL-20/CMDB propellant) was studied by microcalorimetry. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The effect of different proportion of CL-20 to the thermal decomposition behavior, kinetics, and thermal hazard was investigated at the same time. The critical temperature of thermal explosion ( T), the self acceleration decomposition temperature ( T), and the adiabatic decomposition temperature rise (Δ T) were calculated to evaluate the thermal hazard of the CL-20/CMDB propellant. It shows that the CMDB propellant with 38% CL-20 has relative lower values of E and lg A, and with 18% CL-20 has the highest potential hazard. [ABSTRACT FROM AUTHOR]

The thermal decomposition behaviors of 1,2,3-triazole nitrate were studied using a Calvet Microcalorimeter at four different heating rates. Its apparent activation energy and pre-exponential factor of exothermic decomposition reaction are 133.77 kJ mol and 10 s, respectively. The critical temperature of thermal explosion is 374.97 K. The entropy of activation (Δ S), the enthalpy of activation (Δ H), and the free energy of activation (Δ G) of the decomposition reaction are 23.88 J mol K, 130.62 kJ mol, and 121.55 kJ mol, respectively. The self-accelerating decomposition temperature ( T) is 368.65 K. The specific heat capacity was determined by a Micro-DSC method and a theoretical calculation method. Specific heat capacity equation is $$ C_{\text{p}} \left( {{\text{J mol}}^{ - 1} {\text{ K}}^{ - 1} } \right) = - 42.6218 + 0.6807T $$ (283.1 K < T < 353.2 K). The adiabatic time-to-explosion is calculated to be a certain value between 98.82 and 100.00 s. The critical temperature of hot-spot initiation is 637.14 K, and the characteristic drop height of impact sensitivity ( H) is 9.16 cm. [ABSTRACT FROM AUTHOR]

The thermal decomposition behavior of 3,4,5-triamino-1,2,4-triazole dinitramide was measured using a C-500 type Calvet microcalorimeter at four different temperatures under atmospheric pressure. The apparent activation energy and pre-exponential factor of the exothermic decomposition reaction are 165.57 kJ mol and 10s, respectively. The critical temperature of thermal explosion is 431.71 K. The entropy of activation (Δ S), enthalpy of activation (Δ H), and free energy of activation (Δ G) are 97.19 J molK, 161.90 kJ mol, and 118.98 kJ mol, respectively. The self-accelerating decomposition temperature ( T) is 422.28 K. The specific heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide was determined with a micro-DSC method and a theoretical calculation method. Specific heat capacity (J gK) equation is C = 0.252 + 3.131 × 10 T (283.1 K < T < 353.2 K). The molar heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide is 264.52 J mol K at 298.15 K. The adiabatic time-to-explosion of 3,4,5-triamino-1,2,4-triazole dinitramide is calculated to be a certain value between 123.36 and 128.56 s. [ABSTRACT FROM AUTHOR]

The thermal behavior of copper(II) 4-nitroimidazolate (CuNI) under static and dynamic states are studied by means of high-pressure DSC (PDSC) and TG with the different heating rates and the combination technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy (thermolysis/RSFTIR). The results show that the apparent activation energy and pre-exponential factor of the major exothermic decomposition reaction of CuNI obtained by Kissinger’s method are 233.2 kJ mol−1 and 1017.95 s−1, respectively. The critical temperature of the thermal explosion and the adiabatic time-to-explosion of CuNI are 601.97 K and 4.4∼4.6 s, respectively. The decomposition of CuNI begins with the split of the C-NO2 and C-H bonds, and the decomposition process of CuNI under dynamic states occurs less readily than those under static states because the dynamic nitrogen removes the strong oxidative decomposition product (NO2). The above-mentioned information on thermal behavior is quite useful for analyzing and evaluating the stability and thermal charge rule of CuNI. [ABSTRACT FROM AUTHOR]