Showing papers by "Zhi-Cheng Tan published in 2013"

Molar heat capacity and thermodynamic properties of crystalline Eu(C 2 H 5 O 2 N) 2 Cl 3 3H 2 O

Abstract: A complex of europium hydrochloric acid coordinated with 2-aminoacetic acid (C2H5O2N), Eu(C2H5O2N)2Cl3·3H2O was synthesized and characterized by IR and elements analysis. The heat capacities of the complex was measured with an automatic adiabatic calorimeter, and the thermodynamic functions [H T − H 298.15] and [S T − S 298.15] were derived in the temperature range from 80 to 340 K with temperature interval of 5 K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric (TG) analysis and differential scan calorimeter (DSC).

Low-temperature heat capacities, and thermodynamic properties of solid–solid phase change material bis(1-octylammonium) tetrachlorocuprate

Abstract: A new crystalline complex (C8H17NH3)(2)CuCl4(s) (abbreviated as C8Cu(s)) was synthesized by liquid phase reaction. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the complex were measured by a precision automatic adiabatic calorimeter over the temperatures ranging from 78 to 395 K, and two solid-solid phase changes appeared in the heat capacity curve. The temperatures, molar enthalpies and entropies of the two phase transitions of the complex were determined to be: T (trs, 1) = 309.4 +/- A 0.35 K, Delta(trs) H (m, 1) = 16.55 +/- A 0.41 kJ mol(-1), and Delta(trs) S (m, 1) = 53.49 +/- A 1.3 J K-1 mol(-1) for the first peak; T (trs, 2) = 338.5 +/- A 0.63 K, Delta(trs) H (m, 2) = 6.500 +/- A 0.10 kJ mol(-1), and Delta(trs) S (m, 2) = 19.20 +/- A 0.28 J K-1 mol(-1) for the second peak. Two polynomial equations of the heat capacities as a function of the temperature were fitted by least-square method. Smoothed heat capacities and thermodynamic functions of the complex relative to the standard reference temperature of 298.15 K were calculated based on the fitted polynomial equations.

Heat Capacity and Thermodynamic Property Studies of Diethyl Acetamidomalonate (C9H15NO5)

Abstract: The heat capacity of diethyl acetamidomalonate (DEAM) has been studied using an adiabatic calorimeter in the temperature range from (78 to 395) K. No thermal anomalies were observed in temperature regions from (78 to 344) K and from (375 to 395) K, where the heat capacity data were fit to two polynomial equations. A solid–liquid phase transition was detected in temperatures from (344 to 375) K. The phase transition temperature, enthalpy, entropy and mole fraction purity of this compound were determined to be 368.72 K, 34.3 kJ·mol–1, 93.0 J·K–1·mol–1 and 0.9997(mole fraction), respectively, based on the experimental data in the phase transition region. The thermodynamic functions of DEAM relative to the reference temperature of 298.15 K were derived based on the fitted heat capacity data in the entire experimental region.