Measurements of Enthalpy Change of Reaction of Formation, Molar Heat Opacity and Constant-Volume Combustion Energy of Solid Complex Yb(Et_2dtc)_3(phen)

摘要

A ternary solid complex Yb(Et_2dtc)_3(phen) was obtained from the reaction of hydrous ytterbium chloride with sodium diethyldithiocarbamate (NaEt_2dtc), and 1, lG-phenanthroline (o-phen-H_2O) in absolute ethanol. The bonding characteristics of the complex were characterized by IR. The result shows Yb~(3+) bands with two sulfur atoms in the Na(Et_2dtc)_3 and two nitrogen atoms in the o-phen. The enthalpy change of liquid-phase reaction of formation of the complex ATH_m(l), was determined as being ( -24.838 + -0.114) kj-mol~(-1) at 298.15 K, by an RD-496 HI type heat conduction microcalormeter. The enthalpy change of the solid-phase reaction of formation of the complexDELTA_rH~sigam_(s), was calculated as being (108.015 + - 0.479) kj o mol~(-1) on the basis of an appropriate thermochemistry cycle. The thermodynamics of liquid-phase reaction of formation of the complex was investigated by changing the temperature during the liquid-phase reaction. Fundamental parameters, the activation enthalpy, DELTAH~(theta) not = the activation entropy, DELTAS ~(theta) not =, the activation free energy, DELTAG~(theta) not = , the apparent reaction rate constant k, the apparent activation energy E, the pre-exponential constant A , and the reaction order n, were obtained by a combination of the reaction thermody-narrac and kinetic equations with the data from the thermokinetic experiments. At the same time, the molar heat capacity of the complex c _m , p , was determined to be (86.34 + - 1.74) J o mol~(-1) o K ~' by the same microcalormeter. The constant-volume combustion energy of the complex, DELTA_cU, was determined to be ( - 17954.08 + -8.11) kj-mol~(-1) by an RBC-II type rotating-bomb calo-rimefer at 298.15 K. Its standard enthalpy of combustion, DELTA_cH~sigma_m, and standard enthalpy of formation, DELTA_fH~(theta)_m, were calculated to be (-17973.29+ -8.11) Id-mol~(-1) and (-770.36+ -9.02) kj-mol~(-1), respectively.