Solution Calorimetry Method Research Articles

Destinezite: physicochemical and calorimetric study

Destinezite (Fe3+ Al0.02)(PO4)0.99(SO4)0.90(OH)1.20 ⋅ 5.97H2O (Czech Republic) has been studied by thermal and electron-microprobe analyses, X-ray powder diffraction, IR, Raman, and Mössbauer spectroscopy. The enthalpy of formation of destinezite Fe3 +(PO4)(SO4)(OH)⋅6H2O from the elements ∆fH0(298.15 K) = −4258 ± 12 kJ/mol was determined by the method of solution calorimetry in melt lead borate 2PbO ⋅ B2O3 on a Calvet microcalorimeter Setaram (France). The value of its absolute entropy S0(298.15 K) = 462.0 J/(mol⋅K) was estimated, the entropy of formation ∆fS0(298.15 K) = −2054 J/(mol⋅K) and the Gibbs energy of formation from the elements ∆fG0(298.15 K) = −3646 kJ/mol.

Vaporization enthalpy of azeotropes by the solution calorimetry method

This work is devoted to the study of the thermochemistry of solvation of azeotropes. The enthalpies of dissolution of azeotropes (binary systems [organic nonelectrolyte – A], where A is acetonitrile, benzene, cyclohexane or n-hexane) in the medium of cyclohexane or n-heptane have been determined. The impact of the structure of the components of the azeotropes on their properties in solution has been discussed. The approach based on the correlations between the enthalpies of solvation and molar refraction has been first used to determine the vaporization enthalpies of azeotropes. Values were found to be in a fairly good agreement with literature data obtained by direct and calculated methods. The findings of this study allow analyzing the structure–property relationships of the azeotropes obtained.

Thermodynamic Properties of Coquimbite and Aluminocoquimbite

Coquimbite AlFe3+3[SO4]6(H2O)12⋅6H2O (sample from the Javier Mine, Peru) has been studied by thermal and electron microprobe analysis, X-ray powder diffraction, Raman spectroscopy, and Mössbauer spectroscopy. The enthalpy of formation of the coquimbite from elements ∆fH0(298.15 K) = −11 118 ± 40 kJ/mol was determined by the method of solution calorimetry in melt of lead borate 2PbO∙B2O3 on a Setaram (France) Calvet microcalorimeter. The value of its absolute entropy S0(298.15 K) = 1248.3 ± 3.0 J/(mol K) was estimated, the entropy of formation ∆fS0(298.15 K) = − 5714.0 ±3.0 J/mol K), and the Gibbs energy of formation from elements ∆fG0(298.15 K) = −9411 ± 40 kJ/mol were calculated. The values of the enthalpy and Gibbs energy of formation of aluminocoquimbite Al2Fe3+2[SO4]6(H2O)12⋅6H2O from elements were estimated at −11 540 ± 29 and −9830 ± 29 kJ/mol, respectively.

Sublimation/vaporization and solvation enthalpies of monosubstituted pyridine derivatives

Different sectors, including medicine and display technology, utilize substituted pyridines. To establish the quality of products manufactured from pyridines, chemical thermodynamics of the solvation and evaporation enthalpies of the pyridines are crucial. The solvation and evaporation enthalpies of the monosubstituted pyridine derivatives were determined in this study. The enthalpy of solvation of the pyridines was determined using the additive scheme method and the solution calorimetry methods. The evaporation enthalpy of the pyridine derivatives was also calculated using solution calorimetry and transpiration methods. As a consequence, solution calorimetry's additive scheme and the transpiration methods were used to determine the 2-iodopyridine's vaporization enthalpy for the first time. The study's sublimation/vaporization enthalpy values were extremely accurate and closely matched those found in the literature. As a result, the impacts of the different attached groups to the pyridine molecule as well as the enthalpies of evaporation and solvation of the monosubstituted pyridine were investigated.

Thermodynamics of complex formation between aspartic acid and 2,3,4-pyridinecarboxylic acids in aqueous solutions

The present work reports on molecular interactions of dicarboxylic amino acid, L-aspartic acid (Asp), with nicotinic acid, isonicotinic acid and picolinic acid in aqueous solutions at 298.15 K. Thermodynamic parameters of complex formation between the reagents were estimated using solution calorimetry method. It was found that strengthening of the stability of the Asp complexes follows the order nicotinic acid < isonicotinic acid < picolinic acid. The process of complex formation between Asp and the pyridinecarboxylic acids in water is entropically favorable. For zwitterionic forms of reagents, DFT theoretical calculations at B3LYP/6-31++G(d,p) level of theory have been performed. Analysis of natural bond orbitals (NBO) has been carried out for the most stable conformers of complexes formed. According to the quantum chemical calculations and thermodynamic data, the complexes between Asp and pyridinecarboxylic acids with 1:2 stoichiometry is mainly formed due to the electrostatic interactions and hydrogen bonding.

Enthalpies of sublimation and vaporization of poly-substituted phenols containing intramolecular hydrogen bonds by solution calorimetry method

A simple procedure for calculation of solvation enthalpy of compounds containing intramolecular hydrogen bond was developed. This procedure is based on the assumption that fragments of molecules containing intramolecular hydrogen bonds can be express as one group contribution. The proposed approach was verified by determination of the vaporization/sublimation enthalpies of poly-substituted phenols. Vaporization/sublimation enthalpies were obtained as difference between solution and solvation enthalpies in benzene. Solution enthalpies of thirteen compounds in benzene were measured in the present study. The obtained vaporization/sublimation enthalpies are in good agreement with values available in the literature. This promising result makes the solution calorimetry method preferable for quick estimations of enthalpy of phase transition, especially for explosive or compounds of low volatility.

Vaporization/sublimation enthalpies of mono- and dimethyl-esters estimated by solution calorimetry method

The additive scheme for calculating the solvation enthalpies of aliphatic compounds has been developed for linear mono- and dimethyl-esters. Ester group contribution to the enthalpy of solvation in n-heptane was obtained. Accuracy of the proposed approach for determination of solvation enthalpies of linear mono- and dimethyl-esters was tested by comparison with experimental solvation enthalpies. In most cases, deviations do not exceed 1 kJ·mol−1.It was found that the dependence of the solution enthalpies of mono- and dimethyl-esters on the number of carbon atoms in the molecule can be fitted by power function. This dependence and a group-additivity scheme for solvation enthalpy were used for estimation of the enthalpies of phase transitions of mono- and dimethyl-esters. Evaluated values of sublimation, vaporization, and fusion enthalpies at 298.15 K are in good agreement with experimental data obtained by conventional methods.

Thermodynamic properties of montechellite

A thermochemical study of natural calcium and magnesium orthosilicate ─ monticellite (Ca1.00Mg0.95)[SiO4] (Khabarovsk Territory, Russia) was carried out on the Tian-Calvet microcalorimeter. The enthalpy of formation from the elements fHоel(298.15 K) = -2238.4 4.5 kJ / mol was determined by the method of high-temperature melt solution calorimetry. The enthalpy and Gibbs energy of formation of monticellite of the theoretical composition of CaMg[SiO4] are calculated: fH0el(298.15 K) = -2248.4 4.5 kJ/mol and fG0el(298.15 K) = -2130.5 4.5 kJ/mol.

Experimental and ab initio study of the Ag–Li system for energy storage and high-temperature solders

The standard enthalpies of formation of the Ag30Li70 and Ag20Li80 gamma phases (cubic, sg. I-43 m) were measured using the solution calorimetry method; the standard enthalpy of formation of the Ag10Li90 alloy, corresponding to a hypothetical γ phase, was determined using the same method. All the measured and literature values of the standard enthalpies of formation of the Ag–Li intermetallic phases were compared with the data calculated using ab initio for stable and unstable phases and Miedema’s model. The XRD pattern for a sample with Ag30Li70 was obtained and it was verified that it contained the γ phase, as expected. Moreover, the structure of the γ-phase for the Ag4Li9 disordered phase was minimized and the vibrational heat capacity at constant volume and the thermal coefficient of linear expansion were calculated using ab initio methods. The simulated XRD pattern of the latter phase was compared with the experimental pattern. It was determined that only one gamma phase, with a homogeneity range not wider than 0.69 ≤ x(Li) ≤ 0.73, is stable for T ≥ 298 K. Furthermore, besides AgLi-β with a homogeneity range of 0.50 ≤ x(Li) ≤ 0.60 at 298 K, a cubic Ag15Li49-β is stable for x(Li) = 0.77. The entropy term stabilizes the cubic structure of the AgLi-β which can be tetragonal at 298 K. The enthalpies and Gibbs energies of formation were calculated at 298, 320, 425, and 600 K. A new “map” of the phases in equilibrium at different temperatures is proposed.

Heat release in chemical reaction between micron aluminum powders and water

In this paper, the micron aluminum powders produced by the dispersion of liquid aluminum were characterized using the method of thermal analysis, scanning electron microscopy, low-temperature nitrogen adsorption (BET) method. The reactivity of the micron aluminum powders in a chemical reaction with an aqueous solution of NaOH was evaluated using the solution calorimetry method. The effect of the sample mass was investigated for different kind of the aluminum micron powder. The heat release is dependent on the aluminum mass in suspension aluminum-water. It is shown that the method of solution calorimetry is applicable for determining the thermal effects of the reaction between aluminum micropowders and water as well as the content of metallic aluminum after long-term storage of micropowders in the airtight containers.

Thermodynamic properties of fluorapophyllite-(k) and hydroxylapophyllite-(k)

Thermochemical study of natural minerals of the apophyllite group: fluorapophyllite-(K) KCa4[Si8O20]F . 8H2O (Maharashtra, India) (I) and hydroxylapophyllite-(K) KCa4[Si8O20]OH . 8H2O (Norilsk, Russia) (II) were performed on a high-temperature heat-flux microcalorimeter Tian–Calvet “Setaram” (France) using the melt solution calorimetry method. The first data on the enthalpies of formation from the elements for the minerals studied are obtained: -13 205±13 kJ/mol (I) and -13 054±20 kJ/mol (II). The values of their standard entropies and Gibbs energies of formation are estimated.

Natural kaersutite: ftir, raman, thermal and thermochemical investigations

A thermochemical study of the natural oxo-amphibole ─ kaersutite Na0.4K0.3(Ca1.6Na0.4)(Mg2.9Fe0.82+Al0.7Ti0.6Fe0.53+)[Si6.1Al1.9O22](OH)0.2O1.8.(alkaline basalts of Mongolia) was performed on a Tian-Calvet microcalorimeter. The enthalpy of formation from the elements ∆fH el0(298.15 K) = – 12102 ± 16 kJ/mol) was obtained by the method of high-temperature melt solution calorimetry. The entropy, enthalpy and Gibbs energy of the formation of the end-members of the isomorphic series kaersutite NaCa2Mg3TiAl[Si6Al2O22]O2 – ferri-kaersutite NaCa2Mg3TiFe3+[Si6Al2O22]O2 were estimated.

Solvation thermochemistry of aromatic hydrocarbons and their halogen derivatives in imidazolium-based ionic liquids

In this work solution enthalpies of aromatic compounds and their halogen derivatives in 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [BMIM][NTf2], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO] were measured by solution calorimetry method. The solvation enthalpies of aromatic compounds and their halogen derivatives in ionic liquids were calculated. Based on experimentally measured solvation enthalpies and calculated non-specific solvation enthalpy the contribution of the solvophobic effect on the solvation enthalpy of dissolved molecules in ionic liquids was demonstrated to be negligible. The correlation between solvation enthalpies of the aromatic compounds and their halogen derivatives in ionic liquids and solute molecules polarizability parameter was found. Also, a comparison of relationships between solvation enthalpy and molar refractions in ionic liquids and molecular solvents was made.

Improving the method of solution calorimetry for evaluation of the enthalpies of phase transitions and condensed state enthalpies of formation

In the present work, n-heptane was tested as a solvent with the zero-thermal effect of solution enthalpy for normal and cyclic alkanes. For alkanes in n-heptane, no obvious dependence of the solution enthalpy on alkyl chain length was found with the absolute values of the solution enthalpy being below the uncertainty of determination.For aliphatic and aromatic compounds, the linear correlation between solvation enthalpy in n-heptane and molar refraction of these solutes was observed. Using evaluated linear fitting and the experimental values of solution enthalpies, the formation enthalpies in the condensed state for some classes of organic compounds were determined. The gas phase enthalpies of formation were computed at DLPNO-CCSD(T)/def2-QZVP level of theory. All experimental and calculated values were in good agreement with the most reliable literature data.The solution enthalpies for thirty-five compounds were experimentally determined using solution calorimetry.

Calorimetric Study of Natural Basic Copper Phosphate—Pseudomalachite

The thermochemical study of a natural basic copper phosphate, pseudomalachite Cu5(PO4)2(OH)4 (Virneberg deposit, Germany), was carried out using high-temperature melt solution calorimetry method with a Tian–Calvet microcalorimeter. The enthalpy of formation of the mineral from elements was obtained to be Δ f Hel(298.15 K) =–3214 ± 13 kJ/mol. The value of the Gibbs energy of pseudomalachite formation calculated using literature data on its standard entropy is Δ f Hel°(298.15 K) =–2812 ± 13 kJ/mol.

Enthalpy of formation of intermetallic phases from Al\u2013Zr system determined by calorimetric solution method

Intermetallic phases represent a group of materials of unique properties. Many of those materials have found practical application, whereas others are still intensively examined. There are ten stable intermetallic phases in Al–Zr system, among which few are prospective materials to work at elevated temperature, nuclear reactors, etc. On top of that, researches are focused on obtaining amorphous phases, nanoparticles and zirconium-based pressure pipes covered with aluminum. As a result, better understanding of thermal effects accompanying those compounds formation becomes crucial. In this paper, solution calorimetry method was used for determination of formation enthalpy ΔfH of intermetallic phases from Al–Zr system at room temperature (298 K). Experiments were conducted using test station built by author. Material used as bath was aluminum. Additionally, alloys preparation methodology was described and presented. Calorimetric measurements were taken on phases: Al3Zr, Al2Zr, Al3Zr2, AlZr, Al2Zr3, AlZr2 and AlZr3. Heat of dissolution of zirconium in aluminum bath at temperature 1073 K was determined experimentally and was equal to − 244.5 ± 5.4 kJ mol−1. Obtained results of enthalpy of formation were summarized and compared with the literature data.

Experimental and Theoretical Thermodynamic Study of Distillable Ionic Liquid 1,5-Diazabicyclo[4.3.0]non-5-enium Acetate

A thermochemical study of the protic ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]), a prospective cellulose solvent considered for the Ioncell-F process, was carried out. The heat capacities of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and [DBNH][OAc] were measured by differential scanning calorimetry (DSC) at 223–323 and 273–373 K temperature ranges, respectively. The enthalpies of fusion and synthesis reaction of [DBNH][OAc] were measured by DSC and reaction calorimetry, respectively. The gas-, liquid-, and solid-phase enthalpies of formation of [DBNH][OAc] and DBN were determined using calorimetric and computational methods. The enthalpy of vaporization of [DBNH][OAc] was estimated from the formation enthalpies. The activity coefficients at infinite dilution of 17 and the enthalpies of solution at infinite dilution of 25 organic solutes in [DBNH][OAc] were measured by gas chromatography and solution calorimetry methods, respectively. The obtained data will be used in the design and...

Calorimetric study of the Li-Zn system

The solution calorimetry method was applied to determine the standard formation enthalpy of the solid intermetallic phases: LiZn, Li2Zn3, LiZn2, Li2Zn5, LiZn4 and the heat of solution of zinc in liquid Sn. These alloys were prepared from pure metallic Li and Zn, which were melted in a glove-box, filled with high purity argon with a very low concentration of impurities. All experiments were performed with the use of Setaram MHTC 96 Line evo calorimeter. The heat of zinc solution in Sn-bath in the temperature range 723–926K was equal on average to (8.6±0.3)kJ·mol−1. The standard formation enthalpy of the solid alloys, with concentrations corresponding to LiZn, Li2Zn3, LiZn2, Li2Zn5, LiZn4 intermetallics, was measured at 723K. The values of the standard formation enthalpy were estimated as {(−15.3±0.5), (−16.3±0.4), (−15.6±0.3), (−15.3±0.3), (−12.3±0.2)} kJ·mol−1 at., for the LiZn, Li2Zn3, LiZn2, Li2Zn5, LiZn4, respectively. They were compared with the data calculated by means of the Miedema model.

Calorimetric and Electromotive Force Measurements of Al-Li-Zn Liquid Solutions

The solution calorimetry and electromotive force methods were used for the study of the mixing enthalpy and partial excess Gibbs energy of the Al-Li-Zn liquid solutions. Calorimetric investigations were conducted for solutions with the ratio of XLi/XAl and XLi/XZn = 0.8/0.2 and at the temperatures of 942 and 978 K, respectively. The electromotive force studies were performed at two temperatures: 873 and 923 K by the titration technique and for dilute solutions. Based on the data of the mixing enthalpy change and the partial excess Gibbs energy of Li available in the literature, together with that obtained in these studies, the ternary interaction parameters were elaborated. The comparative analysis of the experimental mixing enthalpy change generally showed a good agreement with the values calculated based on different models. The observed deviations between the experimental and the calculated values were, for most of the experimental data, lower than 1 kJ/mol. The experimental partial excess Gibbs energy of Li showed a satisfactory agreement with that modeled on the basis of the ternary parameters elaborated in this work.

Natural Mg-Fe clinochlores: Enthalpies of formation and dehydroxylation derived from calorimetric study

This paper presents the results of the first experimental thermochemical investigation of two natural trioctahedral chlorites (clinochlores). The study was performed with the help of a high-temperature heat-flux Tian-Calvet microcalorimeter. The samples were characterized by X-ray spectroscopy analysis, X-ray powder diffraction, thermal analysis, and FTIR spectroscopy. The enthalpies of formation of clinochlores were found using the melt solution calorimetry method to be: −8806 ± 16 kJ/mol for composition ( Mg 4 . 9 Fe 0 . 3 2 + Al 0 . 8 ) [ Si 3 . 2 Al 0 . 8 O 10 ] ( OH ) 8 and −8748 ± 24 kJ/mol for composition ( Mg 4 . 2 Fe 0 . 6 2 + Al 1 . 2 ) [ Si 2 . 8 Al 1 . 2 O 10 ] ( OH ) 8 The experimental data for natural samples allowed calculating the enthalpies of formation for end-members and intermediate members of the clinochlore (Mg 5 Al)[Si 3 AlO 10 ](OH) 8 and chamosite (Fe 5 Al)[Si 3 AlO 10 ](OH) 8 series. An important feature of the clinochlore structure is the presence of two distinct hydroxyl-containing octahedral layers: the interlayer octahedral sheet and octahedral 2:1 layer; the enthalpies of water removal from these positions in clinochlore structure were determined as: 53 ± 20 kJ/(mol·H 2 O) and 131 ± 10 kJ/(mol·H 2 O), respectively. These obtained first thermodynamic characteristics of Mg-Fe clinochlores can be used for quantitative thermodynamic modeling of geological and industrial processes including clinochlores of different composition.