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The methoxy-, hydroxy-, and carbonyl-substituted benzenes are the simplest fragments from the lignin separation feedstocks. Extensive experimental thermochemical studies of these compounds were car...

Indole and methylindole are heterocyclic aromatics, which can be hydrogenated and used for hydrogen storage. A huge advantage of heterocyclic components compared to homocyclic aromatics is the lowe...

Vapour pressures and standard molar enthalpies of vaporization of trans-anethole, estragole, eugenol, and trans-isoeugenol were derived by the transpiration method. A large number of the primary experimental results on temperature dependences of vapour pressures have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies at the reference temperature 298.15 K. The available data were evaluated and validated with help of empirical methods based on gas-chromatographic measurements and structure-property relationships.

The composite material on the base of Al2O3 and SAPO-11 was prepared with a various concentration on SAPO-11 and investigated as a carrier of bifunctional Pt-based catalyst for n-alkanes hydroisomerization. The Al2O3-SAPO-11 composite material with an optimal composition and acidic properties was used to prepare bifunctional catalysts with different hydrogenation/dehydrogenation sites. The effectiveness of the Pt, Pd, Ni and CoMoS active sites of bifunctional catalysts supported on the composite Al2O3-SAPO-11 carrier were investigated and compared in n-hexadecane hydroisomerization. Synthesized materials were investigated using X-ray powder diffraction, scanning electronic and high-resolution transition electronic microscopies, N2 physisorption, NH3-TPD and pyridine-FTIR spectroscopy. A CoMoS active phase was studied as hydrogenation/dehydrogenation hydrogenated-dehydrogenated active sites of bifunctional hydroisomerization catalysts.

This paper suggests a mathematical model of processing experimental data that allows to plot the surface of the phase transition in near critical region, using the results of isochoric experiment. The model is based on proven approximation methods. The model was tested on 20 binary mixtures (10 mixtures of С2-С7 linear alkanes, five mixtures of propane and branched С5-С6 alkanes, two mixtures of haloalkanes, one mixture each of pentane with toluene, cyclohexane with benzene and toluene) with the difference in critical temperatures from 45 to 235 K. As the result, in the 0.5≤ρDew/ρc

Amino-alcohols are considered for sustainable hydrogen storage systems based on catalytic peptide formation. Experimental and theoretical thermochemical studies of amino-alcohols have been performed, including vapour pressure measurements, combustion calorimetry, and quantum-chemical calculations. The standard molar enthalpies of vaporization of amino-alcohols were calculated from the temperature dependence of the vapour pressures measured by the transpiration method. Energies of combustion for six amino-alcohols were measured using the high-precision combustion calorimetry. The available in the literature primary data on vapour pressures, enthalpies of vaporization, and enthalpies of formation of amino-alcohols were collected and evaluated. The experimental standard molar gas-phase enthalpies of formation of amino-alcohols were derived from the evaluated results. The high-level G3B3, G3MP2, and G4 quantum-chemical methods were used to establish consistency of the experimental and theoretical results. The surprisingly low enthalpy of reaction of the reversible dehydrogenation of 2-amino-ethanol, calculated from the experimental data, makes this liquid organic hydrogen carrier system (LOHC) promising for further optimization and development.

One of the promising directions for accumulating hydrogen is its binding into a liquid organic hydrogen carrier (LOHC). In this concept, a LOHC is loaded with hydrogen (hydrogenation) during production and then discharged again (dehydrogenation) when the hydrogen is needed. Biphenyl is an interesting option as potential LOHC due to its reasonable storage capacity. This paper deals with the experimental chemical equilibrium study and a detailed analysis of the biphenyl hydrogenation reactions. We evaluated the consistent set of vapour pressures and standard molar thermodynamic properties of biphenyl derivatives with help of complementary vapour pressure measurements, and empirical and quantum-chemical calculations. The chemical equilibrium constants of hydrogenation-dehydrogenation and thermodynamic characteristics for the biphenyl system were determined.

This work contributes to our primary interest in applications of experimental and computational thermochemistry methods for providing the basic data required in chemical-process design. Pyrazine derivatives are considered as a seminal liquid organic hydrogen carriers. The standard molar enthalpies of vaporisation/sublimation of pyrazine derivatives were derived from the vapour pressure temperature dependences measured by the static and transpiration method. Enthalpies of fusion of the solid compounds were measured using DSC. Thermodynamic data on solid–gas, liquid–gas, and solid–liquid phase transitions available in the literature were collected and combined with own experimental results. We have evaluated and recommended the set of vaporisation and formation enthalpies of pyrazine derivatives at 298.15 K as the reliable benchmark properties for further thermochemical calculations. Gas phase molar enthalpies of formation of pyrazine derivatives calculated by the high-level quantum-chemical method G4 were in agreement with the recommended experimental data. Compilation of experimental and theoretical results derived in this work is useful for optimisation of hydrogenation/dehydrogenation reactions involved in the hydrogen storage technologies.

Vanillin and its isomers are a promising biobased building blocks for monomer synthesis. Extensive experimental thermochemical studies of these compounds have been carried out, including combustion calorimetry, vapor pressure measurements, and differential scanning calorimetry. We have collected available primary experimental results on enthalpies of formation and vapour pressures as well as on phase transitions liquid–gas, liquid–solid, crystal-liquid. These data were evaluated using empirical, semi-empirical and quantum chemical methods. The consistent sets of evaluated thermodynamic data were used to design the method for predicting enthalpies of vaporization and enthalpies of formation of di- and tri-substituted benzenes. It is expected that parameters and pairwise interactions will be transferable to predict the thermochemical properties of poly-methoxy-substituted and poly-hydroxy-substituted benzenes that appear in reaction products of lignin transformations in the value-adding chemicals and materials.

Glycerol and diols are valuable renewable sources for manufacturing of fuel additives via reactive systems of acetals synthesis. Knowledge of thermodynamic data for reactions participants involved in valorisation of glycerol and diols is required. The liquid phase standard molar enthalpy of formation of glycerol formal was measured by the high-precision combustion calorimetry. Standard molar enthalpies of vaporisation of glycerol formal, 1,3-dioxane, 1,4-dioxane, and dimethyl-1,3-dioxanes were derived from temperature dependences of vapour pressure measured with help of transpiration method. Temperature dependences of vapour pressures for acetals available in the literature have been collected and treated uniformly in order to derive recommended sets of vapour pressures and vaporisation enthalpies at the reference temperature 298.15 K. Enthalpies of vaporisation of these compounds were obtained by the transpiration method. Experimental results for glycerol formal were validated by the high-level G4 quantum-chemical method. Enthalpies of the acetalisation reactions of glycerol and diols were estimated and discussed.