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Summary  

The binary systems of C60with α-methyl- and α-chloronaphthalene have been studied by means of differential scanning calorimetry. C60was found to form the molecular complex of the van der Waals type with α-methylnaphthalene which melts incongruently below the boiling point of the solvent at temperature 382.73.0 K. The enthalpy of the desolvation reaction is 14.10.5 kJ mol-1of C60. The molar ratio of fullerene to solvent in the solvate is 1:1.5. In the system C60-α-chloronaphthalene a two-stage incongruent melting process has been observed at temperatures 314.14.6 K and 375.77.4 K with the enthalpies 8.12.6 kJ mol-1and 11.61.0 kJ mol-1, respectively. The composition of the most solvated phase equilibrated with the saturated solution at room temperature and below the first of the incongruent melting transitions was determined as 1:1.5. Based on the results obtained the thermodynamic characteristics of the incongruent melting reactions have been revealed and influence of solvate formation on solubility of C60has been discussed.

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Low temperature heat capacity of ammonium, rubidium and cesium perbromates has been studied by method of adiabatic calorimetry. Anomaly of the heat capacity of cesium perbromate has been found, which corresponds to a structural phase transition. The separation of heat capacity into components has been carried out by the additive scheme. The torsion oscillation of BrO4 anions in solid perbromates at low temperatures has been found. Ammonium ions retardedly rotate aroundC 2 axes in the crystal lattice of NH4BrO4.

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Abstract  

The heat capacities of fenpropathrin in the temperature range from 80 to 400 K were measured with a precise automatic adiabatic calorimeter. The fenpropathrin sample was prepared with the purity of 0.9916 mole fraction. A solid—liquid fusion phase transition was observed in the experimental temperature range. The melting point, T m, enthalpy and entropy of fusion, fus H m, fus S m, were determined to be 322.48±0.01 K, 18.57±0.29 kJ mol–1 and 57.59±1.01 J mol–1 K–1, respectively. The thermodynamic functions of fenpropathrin, H (T)H (298.15), S (T)S (298.15) and G (T)G (298.15), were reported with a temperature interval of 5 K. The TG analysis under the heating rate of 10 K min–1 confirmed that the thermal decomposition of the sample starts at ca. 450 K and terminates at ca. 575 K. The maximum decomposition rate was obtained at 558 K. The purity of the sample was determined by a fractional melting method.

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Abstract  

The temperature dependence of the molar heat capacity (C0 p) of hydrofullerene C60H36 between 5 and 340 K was determined by adiabatic vacuum calorimetry with an error of about 0.2%. The experimental data were used for the calculation of the thermodynamic functions of the compound in the range 0 to340 K. It was found that at T=298.15 K and p=101.325 kPa C0 p (298.15)=690.0 J K−1 mol−1,Ho(298.15)−Ho(0)= 84.94 kJ mol−1,So(298.15)=506.8 J K−1 mol−1, Go(298.15)−Ho(0)= −66.17 kJ mol−1. The standard entropy of formation of hydrofullerene C60H36 and the entropy of reaction of its formation by hydrogenation of fullerene C60 with hydrogen were estimated and at T=298.15 K they were ΔfSo= −2188.4 J K−1 mol−1 and ΔrSo= −2270.5 J K−1mol−1, respectively.

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Abstract  

The heat capacities of trans-(R)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid in the temperature range from 78 to 389 K were measured with a precise automatic adiabatic calorimeter. The sample was prepared with the purity of 0.9874 mole fraction. A solid-liquid fusion phase transition was observed in the experimental temperature range. The melting point, T m, enthalpy and entropy of fusion, Δfus H m, Δfus S m, were determined to be 344.75±0.02 K, 13.75±0.07 kJ mol−1, 39.88±0.21 J K−1 mol−1, respectively. The thermodynamic functions of the sample, H (T)-H (298.15), S (T)-S (298.15) and G (T)-G (298.15), were reported with a temperature interval of 5 K. The thermal decomposition of the sample was studied by TG analysis, the thermal decomposition starts at ca. 421 K and terminates at ca. 535 K, the maximum decomposition rate was obtained at 525 K. The order of reaction, pre-exponential factor and activation energy, are n=0.14, A=1.15·108 min−1, E=66.27 kJ mol−1, respectively.

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Abstract  

By adiabatic vacuum and dynamic calorimetry, heat capacity for poly[bis(trifluoroethoxy)phosphazene] has been determined over the 6–620 K range. Physical transformations of the polymer on its heating and cooling have been detected and characterized. Smoothed heat capacity C p 0(T) and standard thermodynamic functions (H 0(T)-H 0(0), S 0(T) and G 0(T)-H 0(0)) of poly[bis(trifluoroethoxy)phosphazene] have been evaluated for the temperature range from T→0 to 560 K. The standard entropy of formation Δf S 0 at T=298.15 K has been also determined. Fractal dimensions D in the heat capacity function of the multifractal variant of Debye’s theory of heat capacity of solids characterizing the heterodynamics of the tested polymer have been determined.

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