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new high-nitrogen complex [Cu(Hbta)]·4HO (Hbta = N, N-bis-(1(2)H-tetrazol-5-yl) amine) was synthesized and characterized by elemental analysis, single crystal X-ray diffraction and thermogravimetric analyses. X-ray structural analyses revealed that the crystal was monoclinic, space group P2(1)/c with lattice parameters a = 14.695(3) Å, b = 6.975(2) Å, c = 18.807(3) Å, β = 126.603(1)°, Z = 4, D = 1.888 g cm, and F(000) = 892. The complex exhibits a 3D supermolecular structure which is built up from 1D zigzag chains. The enthalpy change of the reaction of formation for the complex was determined by an RD496–III microcalorimeter at 25 °C with the value of −47.905 ± 0.021 kJ mol. In addition, the thermodynamics of the reaction of formation of the complex was investigated and the fundamental parameters k, E, n, $$ \Updelta S_{ \ne }^{{{\uptheta}}} $$, $$ \Updelta H_{ \ne }^{{{\uptheta}}} $$, and $$ \Updelta G_{ \ne }^{{{\uptheta}}} $$ were obtained. The effects of the complex on the thermal decomposition behaviors of the main component of solid propellant (HMX and RDX) indicated that the complex possessed good performance for HMX and RDX. [ABSTRACT FROM AUTHOR]

A novel complex [Ni(H2O)4(TO)2](NO3)2·2H2O (TO = 1,2,4-triazole-5-one) was synthesized and structurally characterized by X-ray crystal diffraction analysis. The decomposition reaction kinetic of the complex was studied using TG-DTG. A multiple heating rate method was utilized to determine the apparent activation energy ( Ea) and pre-exponential constant ( A) of the former two decomposition stages, and the values are 109.2 kJ mol−1, 1013.80 s−1; 108.0 kJ mol−1, 1023.23 s−1, respectively. The critical temperature of thermal explosion, the entropy of activation (Δ S≠), enthalpy of activation (Δ H≠) and the free energy of activation (Δ G≠) of the initial two decomposition stages of the complex were also calculated. The standard enthalpy of formation of the new complex was determined as being −1464.55 ± 1.70 kJ mol−1 by a rotating-bomb calorimeter. [ABSTRACT FROM AUTHOR]

The heat capacities of Ln(Me2dtc)3(C12H8N2) (Ln = La, Pr, Nd, Sm, Me2dtc = dimethyldithiocarbamate) have been measured by the adiabatic method within the temperature range 78–404 K. The temperature dependencies of the heat capacities, C p,m[La(Me2dtc)3(C12H8N2)] = 542.097 + 229.576 X − 27.169 X2 + 14.596 X3 − 7.135 X4 (J K−1 mol−1), C p,m[Pr(Me2dtc)3(C12H8N2)] = 500.252 + 314.114 X − 17.596 X2 − 0.131 X3 + 16.627 X4 (J K−1 mol−1), C p,m[Nd(Me2dtc)3(C12H8N2)] = 543.586 + 213.876 X − 68.040 X2 + 1.173 X3 + 2.563 X4 (J K−1 mol−1) and C p,m[Sm(Me2dtc)3(C12H8N2)] = 528.650 + 216.408 X − 16.492 X2 + 12.076 X3 + 4.912 X4 (J K−1 mol−1), were derived by the least-squares method from the experimental data. The heat capacities of Ce(Me2dtc)3(C12H8N2) and Pm(Me2dtc)3(C12H8N2) at 298.15 K were evaluated to be 617.99 and 610.09 J K−1 mol−1, respectively. Furthermore, the thermodynamic functions (entropy, enthalpy and Gibbs free energy) have been calculated using the obtained experimental heat capacity data. [ABSTRACT FROM AUTHOR]

Low-temperature heat capacities of 2-pyrazinecarboxylic acid (C5H4N2O2)(s) were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of temperature was fitted by least squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at 10 K intervals. The constant-volume energy of combustion of the compound at T = 298.15 K was measured by a precision rotating-bomb combustion calorimeter to be ΔcU = -(17839.40 ± 7.40) J g-1. The standard molar enthalpy of combustion of the compound was determined to be ΔcH0m = -(2211.39 ± 0.92) KJ mol-1, according to the definition of combustion enthalpy. Finally, the standard molar enthalpy of formation of the compound was calculated to be ΔfH0m = -(327.82 ± 1.13) kJ mol-1 in accordance with Hess law. [ABSTRACT FROM AUTHOR]

Abstract: The constant-volume combustion energy, (DNTF, s, 298.15K) and kinetic behavior of the exothermic decomposition reaction of the title compound (DNTF) are determined by a precise rotating bomb calorimeter and DSC, respectively. Its standard enthalpy of combustion, (DNTF, s, 298.15K), standard enthalpy of formation, (DNTF, s, 298.15K) and kinetic parameters of the major exothermic decomposition reaction in a temperature-programmed mode [the apparent activation energy (Ea) and pre-exponential factor (A)] are calculated. The values of (DNTF, s, 298.15K), (DNTF, s, 298.15K), and (DNTF, s, 298.15K) of DNTF are -9733.96 ± 8.59Jg-1, -3018.29 ± 2.68kJmol-1, and 657.23 ± 2.70kJmol-1, respectively. The kinetic model function in integral form and the value of Ea and A of the major exothermic decomposition reaction of DNTF are , 177.03kJmol-1 and 1013.68s-1, respectively. The critical temperature of thermal explosion of DNTF is 240.6°C. [Copyright &y& Elsevier]

A novel amino acid ionic liquid [C4mim][Gly] (1-butyl-3-methylimidazolium glycine) was prepared by a neutralization method. The molar enthalpies of dilution, ΔDHm(mi→mf), of aqueous [C4mim][Gly] at various molalities were measured at (298.15 ± 0.01) K. The values of the apparent relative molar enthalpy, φL, were calculated by using both the extended Debye−Hückel equation and the Pitzer equation, which were in good agreement within experimental error. In terms of φL, the molar enthalpies of solution of [C4mim][Gly], ΔsHm, at various molalities were estimated. The estimated values of ΔsHmwere consistent with the experimental values previously obtained. [ABSTRACT FROM AUTHOR]