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Background: Chlorzoxazone (CHZ) is a water-insoluble drug having bioavailability problems. The absorption rate of such drugs can be improved by reducing their particle size. In this work, the crystal growth kinetics of CHZ–ethanol for different degrees of supersaturation (SS) has been studied. Method: The equilibrium solubility data of CHZ in ethanol is determined by the shake-flask method within the 283.15–313.15 K temperature range. The mole fraction solubility of CHZ is calculated and correlated with the modified Apelblat equation, λh equation, van’t Hoff equation, Wilson, and non-random two liquid (NRTL) equation. Batch crystallization experiments are performed on three different degrees of SS-1.16, 1.18, and 1.20 at 293.15 K as a function of time. Results: The maximum root mean square difference (RMSD) and relative average deviation (RAD) values of 169.24 x10-6 and 0.699 x10-2, respectively, are observed in the NRTL equation model. The dissolution properties such as standard enthalpy, standard entropy, and Gibbs free energy are predicted using van’t Hoff equation. Using a simple integral technique, the average crystal growth rate constant KG is calculated as 1.58 (μm/min) (mg/ml)-1 and the order n=1 for CHZ–ethanol at 293.15 K. Conclusion: The obtained result concludes that the crystals growth size is found to be varied at different SS ratio in batch crystallization. The particle size control in batch crystallization can be achieved by optimizing the operating conditions to get the desired size crystals.

The temperature dependence of the heat capacity of triphenylbismuth dibenzoate Ph3Bi(OC(O)Ph)2 is measured for the first time in the range of Т = (6 and 480) K using precision adiabatic vacuum and differential scanning calorimeters. It is found that the melts with decomposition in the considered range of temperatures, and its standard thermodynamic characteristics are analyzed. Standard thermodynamic functions of Ph3Bi(OC(O)Ph)2 in the crystalline state from Т → 0 to 417 K are calculated using the obtained experimental data. The chain-planar topological structure of the compound is established by subjecting the low-temperature heat capacity to multifractal treatment. The data are used to determine w the compound’s standard entropy of formation ∆fS° in the crystal state at T = 298.15 K. The thermodynamic properties of triphenylbismuth dibenzoate and triphenylantimony dibenzoate are compared, as are the compounds’ thermodynamic characteristics of fusion.

The humic substance is a low-cost and effective adsorbent with abundant functional groups in remediating uranium (U) (VI)-contaminated water. In this research study, leonardite together with leonardite-derived humic acid (L-HA) was used to eliminate U(VI) from water under diverse temperatures (298, 308, and 318 K). L-HA showed a higher adsorption volume for U(VI) than leonardite. U adsorption was varied with pH and increased with temperature. The adsorption kinetics of L-HA had a higher determination coefficient (R2) for pseudo-second-order (R2 > 0.993) and Elovich (R2 > 0.987) models, indicating possible chemisorption-assisted adsorption. This was further supported with the activation energies (15.9 and 13.2 kJ/mol for leonardite and L-HA, respectively). Moreover, U(VI) equilibrium adsorption on leonardite was better depicted with the Freundlich model (R2 > 0.970), suggesting heterogeneous U(VI) adsorption onto the leonardite surface. However, U(VI) adsorption onto L-HA followed the Langmuir equation (R2 > 0.971), which implied the dominant role of monolayer adsorption in controlling the adsorption process. Thermodynamic parameters, including standard entropy change (ΔS0 > 0), Gibbs free energy (ΔG0 0), suggested a spontaneous and endothermal adsorption process. In addition, ionic species negatively affected U(VI) adsorption by leonardite and L-HA.

In this study, the purification efficiency of paclitaxel was remarkably improved through ultrasonic acetone-pentane fractional precipitation. The time taken for precipitation was also shortened by a maximum of 192-fold (at 5°C, 180-250 W) with ultrasound as compared to that of the conventional method. The precipitation was completed within 30 min regardless of temperature (5-25°C), thereby improving the operating conditions (precipitation time and temperature) as compared to the conventional method. In addition, the rate constant in the fractional precipitation with ultrasound (80-250 W) was also increased by 8-to 13-fold (at 5°C) as compared to the conventional method. The standard enthalpy change and standard entropy change were negative, while the standard Gibbs free energy change was positive. These results indicate that the precipitation process was exothermic, irreversible, and non-spontaneous.

Periodicity in electronic molar entropy values has been shown on the basis of the electronic structures of the elements. Also, with the approximations discussed herein, one can estimate the electronic molar entropy without atomic spectroscopy results. All of this can be accomplished by showing the connection between the vector model of the atom and statistical thermodynamics in its quantum mechanical form.

Silica gels based on Silochrome S-120 chemically modified with malonic ester chelates are studied using a set of physicochemical analytical techniques. The effect that a grafted layer of nickel, cobalt, or copper malonates has on the thermodynamic properties of adsorption of organic compounds from different classes on silica gel is investigated via gas chromatography. The test compounds are n-alkanes (C6–C9), chlorinated alkanes, alkenes, and adsorptives whose molecules exhibit different electron-donating and electron-withdrawing properties. Values for differential molar heat of adsorption $${{\bar {q}}_{{{\text{dif}}{\text{,1}}}}}$$ change in standard differential molar entropy $$\Delta \bar {S}_{{1,C}}^{{\text{S}}}$$ , and contributions $$\Delta {{\bar {q}}_{{{\text{dif}}{\text{,1(spec)}}}}}$$ to the energies of dispersive and specific interactions are calculated from experimental retention data for the considered adsorptives. The effect the metal ion of modifying malonate has on the parameters of thermodynamic retention is demonstrated.

The alloys of the Gd-Te system in the range of compositions > 75 at% Te were studied by the methods of X-ray diffraction (XRD) and electromotive forces (EMF). From the EMF measurements of the concentration cells relative to the GdTe electrode in the 300-450 K temperature range, the partial thermodynamic functions of GdTe in alloys were determined. By combining these data with the corresponding functions of Gd in GdTe, the partial molar functions of gadolinium in GdTe3+Te alloys, and standard thermodynamic functions of formation and standard entropy of the GdTe3 compound were calculated. The obtained results were compared with the literature data.

The ratio between the volume of the stationary phase and the void volume of column in HPLC is known as the phase ratio (denoted by Φ). In almost all the thermodynamic studies based on van’t Hoff plots for estimating the values of standard enthalpy and standard entropy, the phase ratio of HPLC column is assumed to be temperature invariant. The validity of this assumption is examined in the present work by studying the variation of Φ with temperature (T) in the range of 20–50 °C for three commercially available C18 columns and two mobile phase compositions methanol/water. A procedure based on proportionality of retention factors k on octanol/water partition coefficients log Kow for several aromatic hydrocarbon homologues was used for the measurement of Φ. Variation of Φ with temperature was previously reported for RP-HPLC separations in an acetonitrile/water mobile phase. However, while for acetonitrile/water mobile phase the effective value of Φ is decreasing as the temperature increases, in the case of methanol/water mobile phase the variation is more complicated. In some cases Φ is decreasing similar to the case of acetonitrile/water mobile phase, but in other cases it decreases up to a point and then shows a slight increase. The study proves that the findings regarding variability of Φ with temperature for the case of acetonitrile/water mobile phase is not an unique effect. In addition, present study evaluates how much the calculation of standard enthalpy and entropy from van’t Hoff plots differ when the variation of Φ with temperature is taken into consideration as compared to the classic approach when Φ is considered a constant.

The calculation of the entropy of flexible molecules can be challenging, since the number of possible conformers grows exponentially with molecule size and many low-energy conformers may be thermally accessible. Different methods have been proposed to approximate the contribution of conformational entropy to the molecular standard entropy, including performing thermochemistry calculations with all possible stable conformations, and developing empirical corrections from experimental data. We have performed conformer sampling on over 120,000 small molecules generating some 12 million conformers, to develop models to predict conformational entropy across a wide range of molecules. Using insight into the nature of conformational disorder, our cross-validated physically-motivated statistical model can outperform common machine learning and deep learning methods, with a mean absolute error ≈4.8 J/mol•K, or under 0.4 kcal/mol at 300 K. Beyond predicting molecular entropies and free energies, the model implies a high degree of correlation between torsions in most molecules, often as- sumed to be independent. While individual dihedral rotations may have low energetic barriers, the shape and chemical functionality of most molecules necessarily correlate their torsional degrees of freedom, and hence restrict the number of low-energy conformations immensely. Our simple models capture these correlations, and advance our understanding of small molecule conformational entropy.

Bedaquiline (trade name Sirturo) is an antibiotic used to treat pulmonary tuberculosis that is resistant to other antibiotics. The pH-spectrophotometric and pH-potentiometric titrations allowed the measurement of two near successive and one distant dissociation constants. The neutral bedaquiline LH molecule was able to protonate and dissociate in pure water to form soluble species L−, LH, $${\text{LH}}_{2}^{ + }$$ , $${\text{LH}}_{3}^{2 + }$$ and $${\text{LH}}_{4}^{3 + }$$ . In the pH range 2–7, three dissociation constants can be reliably estimated. REACTLAB (UV-metric spectral analysis) values are: $${\text{p}}K_{{{\text{a}}1}}^{T}$$ = 3.91(09), $${\text{p}}K_{{{\text{a}}2}}^{T}$$ = 4.58(12) and $${\text{p}}K_{{{\text{a3}}}}^{T}$$ = 5.26(07) at 25 °C and $${\text{p}}K_{{{\text{a}}1}}^{T}$$ = 3.61(30), $${\text{p}}K_{{{\text{a2}}}}^{T}$$ = 4.44(15) and $${\text{p}}K_{{{\text{a3}}}}^{T}$$ = 5.54(33) at 37 °C. ESAB (pH-metric analysis) values are: $${\text{p}}K_{{{\text{a}}1}}^{T}$$ = 3.21(39), $${\text{p}}K_{{{\text{a2}}}}^{T}$$ = 3.68(31) and $${\text{p}}K_{{{\text{a3}}}}^{T}$$ = 5.21(42) at 25 °C and $${\text{p}}K_{{{\text{a}}1}}^{T}$$ = 3.31(12), $${\text{p}}K_{{{\text{a2}}}}^{T}$$ = 3.67(15) and $${\text{p}}K_{{{\text{a3}}}}^{T}$$ = 5.73(08) at 37 °C. Molar enthalpy ΔH0, molar entropy ΔS0 and Gibbs energy ΔG0 were calculated from the spectra using the dependence of ln K on 1/T. The potentiometric data showed positive enthalpy ΔH0(pKa1) = 85.49 kJ·mol−1, ΔH0(pKa2) = 86.42 kJ·mol−1, and ΔH0(pKa3) = 65.84 kJ·mol−1 values and the dissociation reactions were endothermic. The entropy ΔS0 at 25 °C was positive for the three dissociation constants ΔS0(pKa1) = 217.47 J·K−1·mol−1, ΔS0(pKa2) = 204.87 J·K−1·mol−1, and ΔS0(pKa3) = 92.63 J·K−1·mol−1 at 25 °C and proved irreversible dissociation reactions.

Thermodynamic analysis of ammonia storage materials such as metal halides, sodium borohydride, water and ammonium hydrogen sulfate was carried out to clarify the stability in the ammoniates. The standard entropy change ΔS0 by ammonia absorption decreased with increase of the electronegativity of cation in metal chlorides and the electronegativity difference in metal halides. It was suggested that the stronger the binding energy, the smaller the entropy change by ammonia absorption. ΔS0 linearly increased with the natural logarithm of the volume difference ΔV of the ammonia storage materials before and after ammonia absorption, whose slope is 11 times of the slope between the entropy and the natural logarithm of the volume of ideal gas. The standard enthalpy change ΔH0 was increased with ΔS0. Based on these experimental relations, we can calculate the ammonia vapor pressure PNH3 by ΔV.

The Bi–S–Te system has been studied using emf measurements in the composition region Bi2S3–Bi2Te3–Te–S at temperatures in the range 300–450 K. We have calculated relative partial molar functions of bismuth in alloys and used the results to obtain self-consistent sets of the standard Gibbs free energy, standard enthalpy, and standard entropy of the Bi2S3, Bi2Te3, and Bi2Te2S compounds and a solid solution with the composition Bi2Te1.8S1.2, based on the last compound. The data obtained for Bi2S3 and Bi2Te3 have been compared to data available in the literature. The thermodynamic functions of Bi2Te2S and Bi2Te1.8S1.2 have been determined for the first time.

Fundamental thermodynamic properties of the synthetic analog of the famatinite mineral - Cu3SbS4 were studied on the basis of electromotive force (EMF) measurements. The EMF of the concentration chains relative to the Cu electrode with a solid electrolyte was measured for the alloys from the Cu3SbS4 + Sb2S3 + S phase region at 300-380K temperature interval. Based on measurement data, the relative partial thermodynamic functions of copper in alloys, the standard thermodynamic functions of formation, as well as, the standard entropy of the Cu3SbS4 ternary compound were calculated for the first time.

Hydroxytyrosol (HXT) (also known as 3,4-dihydroxyphenylethanol,) is a biophenol extracted from olive. HXT is known for its high antioxidant significance effect. In this work, we focused on the study of the behavior of the solubility of HXT in binary solvent mixtures (ethanol + water) as well as the thermodynamic proprieties. The solubility of HXT in water, ethanol and in binary solvent mixtures (ethanol + water) was measured at five different temperatures from (293.15 to 318.15) K. The enthalpy of fusion and the melting point of HXT were experimentally determined since they are essential for the study of the of solubility and crystallization process. Thermodynamic properties of dissolution of the HXT (Gibbs energy (ΔsolG°), molar enthalpy of dissolution (ΔsolH°), and molar entropy of dissolution (ΔsolS°)) are predicted using the van’t Hoff analysis, the Gibbs equation, and the measured solubilities data. The preferential solvation has been determined using the inverse Kirkwood–Buff integral (IKBI) theory.

Thermodynamic data for radium for radioactive waste management have been predicted using an electrostatic model and correlation with the ionic radii of the alkaline earth metals. Estimation of the standard Gibbs free energy of formation and standard molar entropy of aqueous radium species and compounds has been based on such approaches as extrapolation of the thermodynamic properties of strontium and barium, and use of a model of ion pair formation. The predicted thermodynamic data for radium have been compared with previously reported values.

We focused on the work function of metals as an index of ion binding property between metals and hydrogen and analyzed the relation between the standard entropy change of metal hydrides and the work function of metals (alloys). The standard entropy change of saline hydrides and metallic hydrides roughly increased with the work function. It was indicated that hydrogen storage alloys consist of metal elements A and B whose work functions are small and large, respectively. The standard entropy changes of alloy-based metal hydrides with different composition ratio ΔS0 linearly increased with the work functions of the alloys Wc. Wc also linearly increased with the bulk modulus Bc. Then, it was found that ΔS0 was proportional to the standard heat of formation ΔH0 because dWc/dBc, dΔS0/dWc and dΔH0/dBc are constant.

Pr6UO12(s) and Er6UO12(s) were synthesized by the citrate nitrate gel combustion method. The synthesis conditions were optimized by characterising the precursors of these uranates heated in the temperature range from 973 to 1473 K using X-ray diffraction analysis and thermo-gravimetric techniques. The solid-state oxide ion conducting galvanic cells were constructed to determine the standard molar Gibbs energy of formation of Pr6UO12(s) and Er6UO12(s) from the measured e.m.f.s in the temperature range of 904–1237 K. The standard molar enthalpy of formation and standard entropies at 298.15 K for RE6UO12(s) (RE = Pr and Er) were derived from the measured Gibbs energy and required data from the literature, using second and third law analysis. The calculated ΔfHom(Pr6UO12,s,298.15 K) and ΔfHom(Er6UO12,s,298.15 K) were −6669 and −6951 kJ mol−1, respectively. The standard entropy values of Pr6UO12(s) and Er6UO12(s) were calculated as 561 and 563 J mol−1 K−1, respectively. A similar trend was observed in ΔfHom(RE6UO12,s,T) and Som(RE6UO12,s,298.15 K) to that of RE2O3 along the rare earth series. The oxygen potential and ternary phase diagrams of the Pr–U–O and Er–U–O systems were calculated using the Gibbs energy data measured in this study.

Aim. To study the dependence of the retention of morpholinium 2-((4-(2-methoxyphenyl)-5-(pyridinyl)-4H-1,2,4-triazol-3-yl)thio)acetate and its technological impurities on temperature, as well as determine the thermodynamic characteristics of the transfer from the mobile phase to the stationary phase using hydrophilic chromatography. Results and discussion. The retention factors depending on the absolute temperature were determined in order to study the thermodynamic parameters of the transfer of analytes from the mobile phase to the stationary one. Based on the van ‘t Hoff equation a curve of lnk dependence on 1/T was constructed. The least squares method was used to create the linear dependence equation. The standard molar enthalpies, as well as the conditional standard entropy of the transfer from the mobile to the stationary phase of the test substances, namely morpholinium 2-((4-(2-methoxyphenyl)-5-(pyridinyl)-4H-1,2,4-triazol-3-yl)thio)acetate, pyridine-4-carbohydrazide, 2-isonicotinoyl-N-(2-methoxyphenyl)hydrazine-1-carbothioamide and 4-(2-methoxyphenyl)-5-(pyridinyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione were calculated. The negative enthalpy of the transfer for all substances shows that the substances are adsorbed on the surface of a silica gel with the release of heat. Therefore, the process of transition of a substance from the mobile phase to the stationary one prevails over the reverse process. Experimental part. The Agilent 1260 Infinity liquid chromatography system consisting of a degasser, binary pump, autosampler, column thermostat, diode array detector was used for our experiments. Conclusions. It has been found that all the compounds studied have a negative value of the transfer enthalpy, and it indicates the predominant transition of these analytes from the mobile phase to the stationary one. Conditional standard entropies of the analyte transfer from the mobile phase to the stationary phase have been calculated, and it has been proven that they significantly affect the transfer process. Received: 11.08.2020 Revised: 25.10.2020 Accepted: 14.11.2020

The molar heat capacity of the crystalline bis(η6-diphenyl)chromium fulleride [(η6-Ph2)2Cr] $$^{{ \bullet + }}$$ [C70] $$^{{ \bullet - }}$$ was determined by precise adiabatic calorimetry over the temperature range T = (6–350) K for the first time. The reversible glass-like transformation was detected on the heat capacity curve of [(η6-Ph2)2Cr] $$^{{ \bullet + }}$$ [C70] $$^{{ \bullet - }}$$ in the interval of T = (12–30) K, and its thermodynamic characteristics were estimated and analyzed. The fundamental thermodynamic functions, namely the enthalpy [H°(T) − H°(0)], the entropy [S°(T)−S°(0)], and the potential Φ° were calculated for the range from T → 0 to 350 K based on the experimentally determined molar heat capacity of [(η6-Ph2)2Cr] $$^{{ \bullet + }}$$ [C70] $$^{{ \bullet - }}$$ . The standard entropy of formation ΔfS° of the investigated fulleride was evaluated at T = 298.15 K. The standard thermodynamic characteristics of [(η6-Ph2)2Cr] $$^{{ \bullet + }}$$ [C70] $$^{{ \bullet - }}$$ were compared with the previously reported data for the studied bis(η6-diphenyl)chromium fulleride [(η6‑Ph2)2Cr] $$^{{ \bullet + }}$$ [C60] $$^{{ \bullet - }}$$ .

The source of pollution of both underground-water and water is the existence of heavy metals in such an environment. constitutes. This research sheds light on the lead (Pb) reactivity with Cadmium (Cd) throughout their transferal in the different soils. The batch technique was used in order to demonstrate the influence of temperature, initiate concentration, adsorption-isotherm. The consequences reveal that the Freundlich model, Langmuir model, Harkin-Jura model, and Halsey model are able to adequately describe the adsorption-isotherm parameter. The adsorption ability of the heavy metals decreased once temperatures increased. On the bases of the highest ability of adsorption (Qm), the order of affinity of Lead and Cadmium for the investigated soil occurred at Pb > Cd, and the maximum capacities of adsorption of competition of two cations are decreased for the same effective sites. The change in the thermodynamic state functions such as standard free-energy (ΔGo), standard entropy (ΔSo), and standard enthalpy (ΔHo) were investigated. The interaction of adsorption is revealed to be exothermic in nature

Herein, the facile one step acid activation of bentonite derived functionalized adsorbent (AB) for the effective remediation of both ionic and non-ionic secondary pesticides, ametryn and metolachlor has been attempted. The surface characteristics of AB were examined by the nitrogen adsorption–desorption analysis, scanning electron microscopy (SEM), and Fourier Transforms Infrared (FTIR) Spectroscopy. The adsorptive behavior was evaluated with respect to the effect of contact time, initial concentrations and solution pH. The equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models, while the adsorption kinetic was analyzed using the pseudo-first order and pseudo-second order kinetic equations. Thermodynamic parameters including the standard enthalpy change (ΔH°), standard entropy change (ΔS°), and Gibbs free energy change (ΔG°) were established. Thermodynamic analysis illustrated that the adsorption process was feasible and exothermic in nature, while the characterization findings verified the alteration of FTIR bands, and a high specific surface area of 464.92 m2/g, with a series of pores distributed over the surface. Equilibrium data was best confronted to the pseudo-second order kinetic model, while the adsorptive removal of ametryn and metolachlor onto AB was satisfactory described by the Langmuir isotherm model, with the monolayer adsorption capacities for ametryn and metolachlor of 2.032 and 0.208 mmole/g respectively. The findings outlined the potential of the newly develop AB for the on-site treatment of pesticide polluted water.

The possibility for tetra-, hexa-, octa-, and decanitrogen to exist was analyzed using the QCISD(T)/TZVP and G4 quantum chemical calculations. The results obtained suggest the existence of only four allotropes of nitrogen whose molecules contain from four to eight atoms, viz., rectangular and tetrahedral N4, open-book N6, and cubic N8. The bond lengths and bond angles were calculated for all compounds, as well as selected thermodynamic parameters (standard enthalpy of formation ΔfHo, standard entropy of formation So, standard Gibbs energy of formation ΔfGo) of the compounds in the gas phase. The enthalpies and entropies of the oxidation reactions of each compound by molecular oxygen were calculated using the results of quantum chemical computations. All the oxidation reactions are highly exothermic and practically irreversible; therefore, the title allotropes of nitrogen may appear to be promising combustible materials.

The aim of the present study was investigate the interaction between bovine serum albumin and triamcinolone. For this purpose, the interaction between BSA and triamcinolone was evaluated by UV–Vis and fluorescence spectroscopy under different temperatures, and different salt concentration at physiological pH (7.4). The binding constant of BSA-Triamcinolone system were evaluated different temperature at constant (pH =7.4) and ionic strength (0.01 M). The binding constant dependence of binding constant on temperature was analysed by Van’t Hoff equation. The standard enthalpy change (DeltaH) and standard entropy change (DeltaS) values were determinated respectively as 9.0 kcal/mol while as 54.1 cal/mol.K.. In addition, the effect of salt concentration investigated for BSA-Triamcinolone system at constant temperature (T=25°C) and increasing salt concentration lead to decrement on the binding constant value. The obtained thermodynamic parameters indicate hydrophobic forces take major role in BSA-Triamcinolone interaction. The arousal of salt concentration prompted to diminution on affinity between Triamcinolone and BSA.

The study of the ZrMo1.5V0.5–H2 system had been carried out by calorimetric method, plotting P–C isotherms and X-ray diffraction analysis. The P = f(C) and ΔH = f(C) dependences were obtained for absorption and desorption processes (P—equilibrium hydrogen pressure absorption or desorption, ΔH—partial molar enthalpy of absorption or desorption, C = H/IMC) at 318, 338 and 368 K and the hydrogen pressure up to 50 atm. Moreover, the ΔSdes. = f(C) dependences were calculated on the base of measured calorimetric data and P–C isotherms (ΔSdes.—partial molar entropy of desorption) for 318, 338 and 368 K experiment temperatures. Obtained data enable us to make the following conclusion: the ΔH = f(C) and ΔSdes. = f(C) dependences change with the hydrogen concentration in the metallic matrix and at the transition from 318 to 368 K. This may be connected with the structural variation in the metallic matrix.

As the concept of quantization matrix becomes an important feature in recent video CODECs, an optimized quantization matrix is being considered in the High-Efficiency Video Coding (HEVC) standard. This paper describes the entropy encoding by familiarizing optimized quantization matrix, and so higher rate of compression can be accomplished over the improved entropy encoding. Experiments show that for the eight benchmark video sequences and PSNR for varying rate of data transmission is explored. Comparative analysis is made with the improved (WE-Encoding) and standard entropy encoding based on the performance measurements. The simulation results show that the proposed method (WE-OQM) can save the originality of the decoded video sequence far better even though the compression rate is increased. In addition, the overall analysis states that the proposed method is 35.29% better than the Standard Encoding and 62.5% better than the WE-Encoding.

The natural hydrous sodium−magnesium sulfate blodite (astrakhanite) Na2Mg(SO4)2 · 4H2O from sediments of saline Lake Bai Shagyr (Russia) is studied. The stages of its decomposition on heating are distinguished using thermal analysis, X-ray diffraction, IR and Raman spectroscopy. The enthalpy of formation of blodite from elements ( $${{\Delta }_{f}}H_{{el}}^{0}$$ (298.15 K) = –3845 ± 13 kJ/mol) is determined on a Tian-Calvet microcalorimeter using high-temperature melt solution calorimetry. The values of standard entropy and Gibbs energy of mineral formation are estimated.

The solubility data of sorbic acid in binary systems of (ethanol + water), (1-propanol + water) and (2-propanol + water) were measured from 283.15 to 323.15 K using the static equilibrium method under atmospheric pressure. It was found that the solubility of sorbic acid in the three binary solvent systems increased with increasing temperature as well as increasing initial mole fraction of organic solvent in these systems. The van’t Hoff–Jouyban–Acree model, the modified Apelblat–Jouyban–Acree model and the CNIBS/R-K model were proposed for correlating the experimental solubility values in various solution systems. Furthermore, the dissolution thermodynamic properties of Gibbs energy change (ΔsolGo), molar enthalpy change (ΔsolHo) and molar entropy change (ΔsolSo) were calculated from the experimental solubility data, using the van’t Hoff equation. The positive values of ΔsolGo, ΔsolHo and ΔsolSo indicate that these dissolution processes of sorbic acid in the solvents studied were all endothermic and entropically favorable. In addition, the change of dissolution enthalpy was the main contributor to the positive value of the molar Gibbs energy of the dissolution process. The experimental solubility and the models used in this work would be conducive to purifying sorbic acid from its crude mixtures.

We present an accurate and a general model to predict the molar entropy of gaseous diatomic molecule substances. The proposed model is derived from the use of the partition function and shows an excellent agreements with experimental data in a wide range of temperature for CsO, CsF and CsCl molecules. The average relative deviation of the obtained values from experimental data is less than 0.3%.

Phase equilibria in the ZrO2–TiO2–MgO system have been studied experimentally using powder X-ray diffraction. Isothermal sections were constructed at 1475 and 1555 K. The eutectoid reaction of δ-phase ↔ Mg2TiO4+T-ZrO2+MgO and the solid transition reaction of δ-phase + MgTiO3 ↔ Mg2TiO4 + T-ZrO2 were determined at temperatures 1503 and 1535 K, respectively. Heat capacity measurements for the δ-phase have been obtained in the temperature range from 210 to 1370 K. Debye temperature of the δ-phase was estimated. Standard entropy for the δ-phase was evaluated. Based on the obtained experimental data, a self-consistent thermodynamic description of the ZrO2–TiO2–MgO system has been developed.

The thermodynamics data of crystalline states of two representative components in blood sugar, d-glucose and d-fructose, are significant in researching artificial synthesis and composition transformation in vivo. The heat capacities of d-glucose and d-fructose over a temperature range of 1.9–300 K were measured and calculated by the heat capacity measurement module of physical property measurement system (PPMS). The heat capacities of two compounds increased steadily with temperature, showing a smooth curve without any thermal anomalies. The heat capacity of d-glucose is greater than that of d-fructose in the range of 0 K

A novel hybrid biocomposite based on amino-thiocarbamate derivative of alginate, carboxymethyl chitosan and TiO2 (TiO2/TSC-CMC) was fabricated and characterized using Fourier transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX). The TiO2/TSC-CMC mass ratio (5.0–30.0%) was optimized and 3TiO2/TSC-CMC (hydrogel beads with TiO2/TSC-CMC mass ratio of 20.0%) was selected as the best sorbent for effective biosorption of Ni(II). Batch sorption experiments were conducted, instantaneous and equilibrium sorption capacities were investigated as function of pH, sorbent dose, initial metal concentration, contact time and temperature. Kinetic data could be well explained through pseudo second order rate equation (PSORE) depicting that the rate determining step involves the transfer of electron density from sorbent functional sites to central metal ion. Langmuir model fitted well with isothermal sorption data and maximum monolayer sorption capacity (qm) was computed as 172 mg/g at pH 6.0 and temperature 298 K. The values of thermodynamic parameters such as standard enthalpy change (16.94 kJ/mol) and standard Gibbs energy change (−18.67, −19.48, −20.57, and −21.38 kJ/mol) and standard entropy change (0.12 kJ/mol·K) concluded that sorption process is endothermic, spontaneous and resulted with increase in randomness. Hence, 3TiO2/TSC-CMC was found efficient and reusable sorbent.

In order to effectively utilize energy of agricultural biomass, there is a need to evaluate energy potential. For such a purpose, chemical exergy and standard entropy of typical agricultural biomass were examined analytically. Element compositions of the exergy and entropy were acquired for further statistical evaluation. Adaptive neuro fuzzy inference system (ANFIS) was used as the statistical methodology for data analyzing. ANFIS is an efficient estimation model among machine learning techniques. The main weakness of the ANFIS is its dimensionality problem with large inputs. Therefore, the main goal in this study was to estimate the parameters’ influence on the chemical exergy and standard entropy prediction in order to reduce the number of inputs. Principal component analysis was used for presentation of the obtained ANFIS predictive models. Obtained results have shown the best predictive performances for standard entropy based on hydrogen as composite element of the agricultural biomass. Exergy prediction was the best for oxygen as composite element of the agricultural biomass. ANFIS coefficient of determination for standard entropy prediction based on hydrogen is 0.9832 and for chemical exergy prediction is 0.919. The results show the high predictive accuracy of ANFIS models.

The thermodynamic behavior of the pseudo-binary Al2O3 – MnO is of high value for the steel industry. However, its phase diagram has been associated with some controversy regarding the equilibrium conditions involving the spinel phase (MnAl2O4) at higher temperatures. One way to handle this issue would be the development of a more accurate Gibbs energy models for this mixed oxide, which by itself demands high precision heat capacity data. In the present article, Al2MnO4 samples are synthesized at 1373 K under a reduced atmosphere (C/CO) and characterized through different methods: transmission electron microscopy (TEM) and X-ray diffraction (XRD). The volumetric behavior of Al2MnO4 has next been addressed through XRD analysis with synchrotron radiation during cooling between 300 and 20 K. Finally, selected samples have been studied in a relaxation calorimeter for measuring CP in the range between 2 to 300 K. A reversible thermal anomaly has been detected, with a peak centered around 33 K. Such phenomena resulted in a measurable contribution to the molar entropy of the spinel phase (4.7 ± 0.05 J/mol.K). Considering this contribution, the mean molar entropy of Al2MnO4 at 298.15 K has shown to be equal to 118.7 ± 0.5 J/mol.K.

Detailed analysis of recently reported variable‐temperature IR (VTIR) spectra of carbon monoxide adsorbed in alkaline zeolites shows how, not only the corresponding values of standard adsorption enthalpy (ΔH0 ) and entropy (ΔS0 ) can be obtained, but also the thermodynamic values of molar entropy and enthalpy which characterize the adsorbed gas phase. In addition, it is shown that the so obtained molar entropy data can lead to new insights into soft molecular modes, which would be hardly accessible by conventional IR spectroscopic techniques., Finding the right system! With selected gas‐solid systems like CO/zeolites, variable temperature infrared spectroscopy allows, inter alia, to gain insight into soft molecular modes, otherwise hardly accessible.

Calcium alkali phosphates Ca(Na,K)PO4 are main constituents of bioceramics and thermochemically produced phosphorus fertilizers because of their bioavailability. Sparse thermodynamic data are available for the endmembers CaNaPO4 and CaKPO4. In this work, the missing data were determined for the low-temperature phase modifications of the endmembers CaNaPO4 and CaKPO4 and three intermediate Ca(Na,K)PO4 compositions. Standard enthalpy of formation ranges from − 2018.3 ± 2.2 kJ mol−1 to − 2030.5 ± 2.1 kJ mol−1 and standard entropy from 137.2 ± 1.0 J mol−1 K−1 to 148.6 ± 1.0 J mol−1 K−1 from sodium endmember β-CaNaPO4 to potassium endmember β′-CaKPO4. Thermodynamic functions are calculated up to 1400 K for endmembers and the sodium-rich intermediate phase β-Ca(Na0.93K0.07)PO4. Functions above 640 K are extrapolated because of the phase transition from low- to high-temperature phase. Impurities in the synthesized intermediate phases γ-Ca(Na0.4K0.6)PO4 and γ-Ca(Na0.35K0.65)PO4 and one additional phase transition around 500 K impeded the determination of high-temperature thermodynamic functions. In general, data for phase transition temperatures agree with the previously reported phase diagrams.

While analyses based on the Arrhenius kinetic model have been successfully applied since its introduction, the Arrhenius model neglects to describe pre-exponential factor in a scientifically meaningful fashion. Since the 1930s, transition-state theory (TST), has met with success in interpreting the pre-exponential factor’s value, allowing a standard entropy of activation to be estimated. However, analyses based on TST’s assumptions have been applied inconsistently in the literature, particularly in corrosion science, leading to difficulty in comparison of standard entropy of activations from different studies. In this work, the foundational principles of TST and standard states are discussed and a standard method to apply TST in analyzing rates of surface reactions is recommended. When full details are not available, reacting species’ concentrations should be normalized to the concentration of active surface sites. For corrosion reactions, conversion relationships are given to convert from units of corrosion rate to surface reaction rate, consistent with TST. This method is dubbed a surface reactant equi-density approximation. Application of this standard to reported data results in adjustments of the standard entropy of activation between − 65 and +50 J/mol K and brings reported entropies into a narrower range of values.

The accuracy of species thermochemical properties is important for predicting combustion characteristics by chemical kinetic models due to their impacts on chemical equilibria of elementary reactions and on backward rate coefficients. As they are frequently estimated based on the group additivity method, the underlying group values directly influence the model prediction accuracy. While a number of studies have recently aimed to improve the accuracy of group values, the dependence of kinetic model predictions on the different groups has not yet been investigated in detail before. In the present work, the impact of group thermochemical parameters on ignition prediction is systematically analyzed by means of sensitivity analysis, employing the oxidation of 2-methylhexane (2-MH) as an example. Very high sensitivities are observed at intermediate temperatures for the peroxy group OO/C/H and its adjacent groups in low-temperature intermediate species. Based on uncertainty analysis, optimization potentials are then determined for the group values of enthalpy of formation, standard entropy, and heat capacity, and they are observed to be considerable for certain groups, especially for the enthalpy of formation values of OO/C/H and its adjacent groups. It is also found that the correct and consistent application of optical isomer corrections in the group additivity method is essential for accurate model predictions. The high optimization potentials of a number of groups motivate the extension of an established kinetic model optimization framework as part of this work, calibrating jointly the rate rules and group values against sets of both global model prediction targets and known species thermochemical properties. This methodology is applied to the considered 2-MH model, yielding very good posterior predictions of ignition characteristics. Overall, the results of this study demonstrate that uncertainties in certain group values will strongly propagate into the model prediction, which motivates future research towards a reduction of those uncertainties.

The fundamental principles and applications of thermodynamics and single-component phase equilibrium are used to explain and quantitatively analyze the operation and performance of the vapor-compression refrigerator (VCR). Carbon dioxide is used as the refrigerant. The four processes (or steps) that comprise the VCR refrigeration cycle are explained. The thermophysical properties of CO2 are used to calculate the heat, work, and changes in internal energy, enthalpy, and entropy for each step. Plots of pressure versus molar volume (Vm), temperature versus Vm, and temperature versus molar entropy are presented. The coefficient of performance, an index of refrigerator efficiency, is calculated.

The temperature dependence of the heat capacity of a first-generation siloxane dendrimer with terminal trimethylsilyl groups is determined for the first time via high-precision adiabatic vacuum calorimetry in the temperature range of 6 to 347 K, and by differential scanning calorimetry in the temperature range of 330 to 410 K. An anomalous change in heat capacity is detected in the range of T = 42–76 K. A transition is observed in the range of T = 137–153 K, due to devitrification of the dendrimer. The thermal stability of the compound is studied via thermogravimetric analysis. The obtained experimental data are used to calculate standard thermodynamic functions of the dendrimer in the temperature range T → 0 to T = 400 K, along with the standard entropy of its formation at T = 298.15 K.

The thermodynamic properties of amorphous hyperbranched pyridine-containing polyphenylene in the 6 to 650 K range of temperatures are studied for the first time via high-precision adiabatic vacuum calorimetry and differential scanning calorimetry. In the low-temperature range of 9 to 14 K, the polymer shows an anomalous change in heat capacity resembling the G transition in its shape. An exothermic effect is detected starting at T = 400 K, and is thought to be due to cross-linking in the studied sample. Standard thermodynamic functions of the polymer for the range of T → 0 to 400 K and the standard entropy of its formation at T = 298.15 K are calculated from the experimental data by means of classical thermodynamics.

The role of peripheral groups (PGs) on dendrimers in the spontaneous higher-level organization of hierarchically assembled nanofibers was investigated in a series of POSS-based dendritic gelators (POSS-Lys-X, X: -Boc, -Cbz, -Fmoc, etc.). We demonstrate that the PGs not only affect the gelation ability in solutions, but also the construction of orderly entangled fibrous supramolecular networks, e.g., "loofah-like" networks. Attributed to the PGs (especially the -Boc group) causing a lower cooperative assembly, the steady state with the lowest potential energy of gelators can be easily achieved by the higher ordering of nanofiber entanglement into superstructures. The -Boc group-containing dendrimers show low molar enthalpy and molar entropy of gelation, which help the construction of unique three-dimensional (3D) "loofah-like" superstructures. In contrast, the high cooperative assembly of the dendrimer (-Cbz as the PG) promotes the gelator into a higher enthalpy gelation process, with a constructed normal fibrous network. Hence, the PGs of POSS-based dendrimers act as the crucial factor in controlling the hierarchical self-assembly via a thermodynamics approach. This research presents new perspectives to explicate the relationships between PGs of dendrimers, supra-architectures and gel performances, which further guide the design of functional supramolecular materials via controllable self-assembly.

The temperature dependence of the specific heat capacity of tetraphenylantimony phenylpropiolate Ph4Sb(OC(O)C≡CPh) in the range of 6–450 K is studied via adiabatic vacuum and differential scanning calorimetry for the first time. The studied compound is found to melt with decomposition. The standard thermodynamic functions $$C_{p}^{ \circ }$$(T), $$H^\circ (T) - H^\circ (0)$$, $$S^\circ (T)$$, and $$G^\circ (T) - H^\circ (0)$$ are calculated for the crystalline Ph4Sb(OC(O)C≡CPh) in the range of Т → 0 to 450 K using the obtained experimental data. Multifractal processing of the low-temperature (T< 50 K) heat capacity of the studied compound is performed, and the chain–sheet topology of its structure is determined. The energy of combustion of crystalline Ph4Sb(OC(O)C≡CPh) at T = 298.15 K is measured with a static bomb inside a combustion calorimeter. The standard enthalpy of combustion, the standard enthalpy of formation ∆fH°, the standard entropy of formation ∆fS°, and the standard Gibbs energy of formation ∆fG° of the substance in the crystalline state at T = 298.15 K are calculated from the obtained experimental data.

Coir-pith derived activated carbon has been shown to be a feasible adsorbent for the extracting pentachlorophenol from aqueous medium. The adsorption was studied by varying the dosage of carbon, contact time, concentration of the adsorbate, temperature and pH. Kinetic studies revealed fast adsorption with equilibrium attained at 60 and 80 min for adsorbate concentrations (10-40 mg/L). The second order model was best described in the experimental kinetics. Analyzed the equilibrium data by applying well known isotherm models. The principle of adsorption has been confirmed by estimation of thermodynamic parameters like standard entropy, enthalpy and free energy.

The research work represents the thermodynamic studies of well known flavonoid quercetin in presence of non-ionic surfactant Tween 80. The studies were performed in hydro-ethanolic solvent system (30% v/v ethanol) at five different temperatures (20–40 °C with difference of 5 °C) in order to analyze the changes in thermodynamic properties with respect to temperature change. As Tween 80 is non-ionic surfactant, 1% sodium chloride solution was added as an electrolyte to ensure the flow of electrons. The conductance studies for the flavonoid-surfactant system were carried out and the data thus obtained was utilized to calculate various thermodynamic parameters i.e. standard enthalpy change (ΔHom), standard entropy change (ΔSom) and standard Gibbs free energy change (ΔGom) of micellization. Overall, the effects of quercetin on micellization process of Tween 80 at different temperatures and hydro-ethanolic solvent have been reported.

Gold nanoclusters (AuNCs) have attracted great attention in bioimaging and drug transportation due to their biocompatibility, but a few studies have shown their potential toxicity. In this paper, for the evaluation of the toxicity of DNA-AuNCs at the molecule level, the interaction between DNA-AuNCs and HSA was studied in detail using various spectral methods. DNA-AuNCs could quench the intrinsic fluorescence of HSA by static quenching. Various thermodynamic parameters were evaluated using the van’t Hoff equation. These results indicated that the interaction of DNA-AuNCs with HSA was spontaneous (ΔG < 0) and was driven by favorable negative standard enthalpy changes (ΔH < 0) and unfavorable negative standard entropy changes (ΔS < 0). Therefore, the main forces in this process were van der Waals forces and hydrogen bonds. Furthermore, the competitive binding experiments indicated that DNA-AuNCs bind primarily to site I of HSA. By analyzing the circular dichroism spectroscopy, synchronous fluorescence and FT-IR spectra, the HSA conformation changed slightly in the presence of DNA-AuNCs, indicating that the potential toxicity of DNA-AuNCs led to structural damage in HSA. This work clarifies the mechanism of binding of DNA-AuNCs to HSA and provides important information for the potential toxicity risks of DNA-AuNCs to human health.

The potential of onion skins for removal of aqueous Cd(II) was investigated. Onion skin powder was chemically modified using thioglycolic acid to develop a suitable, low-cost, and efficient adsorbent for the removal of Cd(II) from aqueous solutions. Influences of temperature, contact time, initial concentration of Cd(II), adsorbent dosage, and pH on the removal of Cd(II) were probed. Optimal adsorption conditions were found at pH 5 and 4, and at 60- and 30-min equilibrium time for the modified and native onion skins, respectively. The equilibrium process was well described by the Freundlich isotherm model. The maximum Cd(II) adsorption capacities, from the Langmuir model, are 17.86 mg/g (modified) and 21.28 mg/g (native). The adsorption process followed the mechanism of physisorption. Pseudo second-order rate equation fitted the kinetic data better than the pseudo first-order rate equation for the two adsorbents. Thermodynamic parameters, such as standard free energy change (ΔG°), standard enthalpy change (ΔH°), and standard entropy change (ΔS°), were calculated for adsorption experimental studies. The results showed that the adsorption of Cd(II) on native/unmodified and modified onion skins was a feasible process and exothermic under the studied conditions. The Cd(II) adsorbed was efficiently desorbed from adsorbent using 0.3 M HCl.