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Pressure DSC for energetic materials. Part 2. Switching between evaporation and thermal decomposition of 3,5-dinitropyrazole. / Gorn, Margarita V.; Monogarov, Konstantin A.; Dalinger, Igor L. и др.
в: Thermochimica Acta, Том 690, 178697, 01.08.2020.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Pressure DSC for energetic materials. Part 2. Switching between evaporation and thermal decomposition of 3,5-dinitropyrazole
AU - Gorn, Margarita V.
AU - Monogarov, Konstantin A.
AU - Dalinger, Igor L.
AU - Melnikov, Igor N.
AU - Kiselev, Vitaly G.
AU - Muravyev, Nikita V.
PY - 2020/8/1
Y1 - 2020/8/1
N2 - Differential scanning calorimetry at an elevated external pressure (Pressure DSC) allows for shifting the vaporization of a sample to higher temperatures, thus often facilitating the direct observation of its thermal decomposition. In the present work, the thermolysis of a promising energetic material 3,5-dinitropyrazole was studied under pressures up to 10 MPa. The thermokinetic analysis of the datasets acquired at 2 and 5 MPa exhibited a pronounced kinetic compensation, thus allowing to build the joint formal kinetic model. The final kinetic scheme is comprised of the two parallel reactions, viz., the first-order process (Ea = 198 kJ mol−1) along with a first-order autocatalysis (Ea = 127 kJ mol−1). The experiment was complemented with the highly accurate CCSD(T)-F12 quantum chemical calculations. Theory revealed an unusual primary decomposition channel, viz., a sigmatropic [1,5]H-shift followed by the pyrazole ring opening yielding a molecular nitrogen and a nitro radical as simple primary products. Apart from this, the comparative thermogravimetry at a normal pressure yielded the vapor pressure of 3,5-dinitropyrazole along with the internally consistent set of phase change enthalpies. In general, the pressure DSC is a facile technique to study the true decomposition kinetics of the compounds that vaporize/sublime in conventional DSC experiments.
AB - Differential scanning calorimetry at an elevated external pressure (Pressure DSC) allows for shifting the vaporization of a sample to higher temperatures, thus often facilitating the direct observation of its thermal decomposition. In the present work, the thermolysis of a promising energetic material 3,5-dinitropyrazole was studied under pressures up to 10 MPa. The thermokinetic analysis of the datasets acquired at 2 and 5 MPa exhibited a pronounced kinetic compensation, thus allowing to build the joint formal kinetic model. The final kinetic scheme is comprised of the two parallel reactions, viz., the first-order process (Ea = 198 kJ mol−1) along with a first-order autocatalysis (Ea = 127 kJ mol−1). The experiment was complemented with the highly accurate CCSD(T)-F12 quantum chemical calculations. Theory revealed an unusual primary decomposition channel, viz., a sigmatropic [1,5]H-shift followed by the pyrazole ring opening yielding a molecular nitrogen and a nitro radical as simple primary products. Apart from this, the comparative thermogravimetry at a normal pressure yielded the vapor pressure of 3,5-dinitropyrazole along with the internally consistent set of phase change enthalpies. In general, the pressure DSC is a facile technique to study the true decomposition kinetics of the compounds that vaporize/sublime in conventional DSC experiments.
KW - 3,5-Dinitropyrazole
KW - Energetic materials
KW - Phase change data
KW - Predictive electronic structure theory
KW - Pressure DSC
KW - Thermokinetic analysis
KW - Thermolysis mechanism
KW - Vapor pressure
KW - STABILITY
KW - FOX-7
KW - STATE
KW - MECHANISMS
KW - PYRAZOLE
KW - VAPOR-PRESSURE
KW - TUNNELING CONTROL
KW - KINETICS
UR - http://www.scopus.com/inward/record.url?scp=85087336233&partnerID=8YFLogxK
U2 - 10.1016/j.tca.2020.178697
DO - 10.1016/j.tca.2020.178697
M3 - Article
AN - SCOPUS:85087336233
VL - 690
JO - Thermochimica Acta
JF - Thermochimica Acta
SN - 0040-6031
M1 - 178697
ER -
ID: 24721705