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Phase Chemistry and Thermochemistry on Coordination Behavior of Zinc Chloride with Leucine
Author(s) -
ShengLi Gao,
SanPing Chen,
RongZu Hu,
QiZhen Shi
Publication year - 2003
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20030210311
Subject(s) - chemistry , enthalpy , standard enthalpy of formation , enthalpy change of solution , zinc , thermochemistry , equilibrium constant , solubility , gibbs free energy , thermochemical cycle , thermodynamics , reaction rate constant , enthalpy of atomization , standard enthalpy of reaction , inorganic chemistry , kinetics , organic chemistry , standard enthalpy change of formation , catalysis , physics , hydrogen production , quantum mechanics
The solubility property of the Z n Cl 2 ‐Leu‐H 2 O (Leu= L‐α‐leucine) system at 298.15 K in the whole concentration range was investigated by the semimicro‐phase equilibrium method. The corresponding solubility diagram and refractive index diagram were constructed. The results indicated that there was one complex formed in this system, namely, Zn(Leu)Cl2. The complex is congruently soluble in water. Based on phase equilibrium data, the complex was prepared. Its composition and properties were characterized by chemical analysis, elemental analysis, IR spectra, and TG‐DTG. The thermochemical properties of coordination reaction of zinc chloride with L‐α‐leucine were investigated by a microcalorimeter. The enthalpies of solution of L‐α‐leucine in water and its zinc complex at infinite dilution and the enthalpy change of solid‐liquid reaction were determined at 298.15 K. The enthalpy change of solid phase reaction and the standard enthalpy of formation of zinc complex were calculated. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constant and three kinetic parameters (the activation energy, the pre‐exponential constant and the reaction order) of the reaction, and the standard enthalpy of formation of Zn(Leu) 2+ (aq) were obtained. The results showed that the title reaction took place easily at studied temperature.