Both calorimetric determination of displacement adsorption enthalpies ΔH and measurement of adsorbed amounts of lysozyme (Lyz) denatured by 1.8 mol L−1 guanidine hydrochloride (GuHCl) on a moderately hydrophobic packings at 298 K, pH 7.0 and various salt concentrations were
carried out. Based on the thermodynamics of stoichiometric displacement theory (SDT) the fractions of thermodynamic functions,
which related to four subprocesses of denatured protein refolding on the surface, were calculated and thermodynamic analysis
that which one of the subprocesses plays major role for contribution to the thermodynamic fractions was made in detail. The
moderately hydrophobic surface can provide denatured Lyz energy and make it gain more conformation with surface coverage or
salt concentration increment. The displacement adsorptions of denatured Lyz onto PEG-600 surface are exothermic, more structure-ordered
and enthalpy driven processes.
The non-isothermal kinetics of dehydration of AlPO4·2H2O was studied in dynamic air atmosphere by TG–DTG–DTA at different heating rates. The result implies an important theoretical
support for preparing AlPO4. The AlPO4·2H2O decomposes in two step reactions occurring in the range of 80–150 °C. The activation energy of the second dehydration reaction
of AlPO4·2H2O as calculated by Kissinger method was found to be 69.68 kJ mol−1, while the Avrami exponent value was 1.49. The results confirmed the elimination of water of crystallization, which related
with the crystal growth mechanism. The thermodynamic functions (ΔH*, ΔG* and ΔS*) of the dehydration reaction are calculated
by the activated complex theory. These values in the dehydration step showed that it is directly related to the introduction
of heat and is non-spontaneous process.
Heat capacity measurements between 293 K and 363 K have been carried out in order to elucidate the different states appearing
in 2-amino-2-methyl-1,3 propanediol (AMP) plastic crystal. The results allowed one of them to be identified as a glassy crystal.
The changes of enthalpy, entropy and Gibbs free energy thermodynamic functions with temperature have been calculated from
the experimental heat capacity values.
Heat capacity Cp(T) of the orthorhombic polymorph of L-cysteine was measured in the temperature range 6–300 K by adiabatic calorimetry; thermodynamic functions were calculated
based on these measurements. At 298.15 K the values of heat capacity, Cp; entropy, Sm0(T)-Sm0(0); difference in the enthalpy, Hm0(T)-Hm0(0), are equal, respectively, to 144.6±0.3 J K−1 mol−1, 169.0±0.4 J K−1 mol−1 and 24960±50 J mol−1. An anomaly of heat capacity near 70 K was registered as a small, 3–5% height, diffuse ‘jump’ accompanied by the substantial
increase in the thermal relaxation time. The shape of the anomaly is sensitive to thermal pre-history of the sample.
Al2O3-Cr2O3 solid solutions with 0, 4, 7, 10 and 20 mol% of corundum were synthesized using a high-pressure/high-temperature apparatus
and characterized by X-ray powder diffraction.
Calorimetric measurements were carried out using DSC-111 (Setaram). Heat capacity was measured by the enthalpy method in a
temperature range of 260–340 K, near magnetic phase transition in pure Cr2O3 (305 K). Magnetic contribution into the heat capacity was derived and found to change irregularly with the composition.
Heat capacity of solid solutions remains constant in a relatively wide range of composition, while the Cp values of the end members differ significantly. This phenomenon is very important for the modeling of the thermodynamic functions
of intermediate solid solutions.
The molar heat capacity Cp,m of 1,2-cyclohexane dicarboxylic anhydride was measured in the temperature range from T=80 to 390 K with a small sample automated adiabatic calorimeter. The melting point Tm, the molar enthalpy ΔfusHm and the entropy ΔfusSm of fusion for the compound were determined to be 303.80 K, 14.71 kJ mol−1 and 48.43 J K−1 mol−1, respectively. The thermodynamic functions [HT-H273.15] and [ST-S273.15] were derived in the temperature range from T=80 to 385 K with temperature interval of 5 K. The thermal stability of the compound was investigated by differential scanning
calorimeter (DSC) and thermogravimetry (TG), when the process of the mass-loss was due to the evaporation, instead of its
The thermodynamic properties of carbosilane dendrimer of second generation with terminal methoxyundecylene groups were studied
between 6 and 340 K by adiabatic vacuum calorimetry: the temperature dependence of the molar heat capacity Cp0 was measured, the physical transformations were established and their thermodynamic characteristics were obtained. The experimental
data were used to calculate the thermodynamic functions Cp0 (T), H0(T)-H0(0), S0(T), G0(T)-H0(0) of the compound in the range 0 to 340 K. from the relation Cp0 (T) the fractal dimension of the dendrimer was experimentally determined. The heat capacity of the dendrimer was compared with
the corresponding additive values calculated from the properties of its constituents - a dendritic matrix (carbosilane dendrimer
of second generation) and the corresponding amount of moles of methyl ester of 11-(tetramethyldisiloxy)undecanoic acid serving
as terminal groups.
A calorimetric investigation was performed on the partition ofn-pentanol in the external oil phase and in the interfacial layer of the water-in-oil microemulsion system sodium dodecyl-benzenesulfonate(DDBS)/n-pentanol/n-heptane/water. The results show that fine changes can be observed in the structure of the water-in-oil emulsion and microemulsion
droplets, such as then-pentanol/DDBS mole ratio increase in the interfacial layer; further, the alcohol/surfactant mole ratio α in the interfacial
layer of the droplets, and also the standard thermodynamic functions of the alcohol transition from the external phase to
the interfacial phase (ΔGe→so
), can be derived from calorimetric data.
The solubility and solubility product of europium trifluoride were measured by radiometric, potentiometric and conductometric
methods. There are significant differences in the values of both solubility and solubility product obtained by the three different
techniques. Due to reasons discussed in the text, radiometric values seem to be more acceptable than the others. The thermodynamic
functions such as ΔH0, ΔG0 and ΔS0 for the dissolution process were also measured. The positive values of ΔH0 and ΔG0 and the negative value of ΔS0 are indicative of the slight solubility of EuF3. The dependence of solubility on pH and also on the fluoride concentration has also been studied. It was confirmed that europium
forms a monofoluoride complex in aqueous solution. The stability constant of this complex was estimated.
DSC and vapour pressure measurements are presented on some Be, Al and Cr complexes with 2,4-pentanedione tetramethyl-3,5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione and hexafluoro-2,4-pentanedione. Thermodynamic functions are given for the sublimation, vaporization and melting processes of the substances.