Benchmark Thermochemistry of N-Methylaniline

© 2015 American Chemical Society. In this work, the standard molar enthalpy of formation in the gaseous state of highly pure N-methylaniline, δfHm° (g, 298.15 K) = 90.9 ± 2.1 kJ·mol-1, has been obtained from the calorimetrically measured energy of combustion converted into the enthalpy of formation, δfHm° (liq, 298.15 K) = 35.9 ± 2.1 kJ·mol-1, and from the molar enthalpy of vaporization, δlgHm = 55.0 ± 0.2 kJ·mol-1, derived from vapor pressure measurements by transpiration method. The enthalpy of formation of N-methylaniline calculated using the quantum chemical G4 method was in excellent agreement with the experimental value. The frequencies of normal vibrations were obtained from the experimental and calculated spectra. Thermodynamic properties of N-methylaniline in the ideal gas state were calculated from molecular and spectral data in the temperature range 100-1500 K

Benchmark thermochemistry of methylbenzonitriles: Experimental and theoretical study

© 2015 Elsevier Ltd. All rights reserved. The gas-phase enthalpies of formation of 2-, 3-, and 4-methylbenzonitrile at T = 298.15 K were studied by combustion calorimetry, and their vaporization enthalpies were determined using the transpiration method. The composite ab initio methods W1-F12 and G4 were used to calculate the gas-phase enthalpies of formation for these three methylbenzonitriles. These theoretical values were found to be in excellent agreement with the corresponding experimental data. The analysis of these data revealed that the interaction between cyano and methyl groups is slightly stabilizing. Using the experimental data a set of group-additivity terms, which allows to estimate thermochemical properties for methyl and cyano substituted benzenes, was proposed. These terms, together with theoretical data, were subsequently used to reassess the thermochemical properties of 2,6-dimethylbenzonitrile and 2,4,6-trimethylbenzonitrile

Catalytic Hydrogen Evolution of NaBH4_4 Hydrolysis by Cobalt Nanoparticles Supported on Bagasse-Derived Porous Carbon

As a promising hydrogen storage material, sodium borohydride (NaBH4) exhibits superior stability in alkaline solutions and delivers 10.8 wt.% theoretical hydrogen storage capacity. Nevertheless, its hydrolysis reaction at room temperature must be activated and accelerated by adding an effective catalyst. In this study, we synthesize Co nanoparticles supported on bagasse-derived porous carbon (Co@xPC) for catalytic hydrolytic dehydrogenation of NaBH$_4$. According to the experimental results, Co nanoparticles with uniform particle size and high dispersion are successfully supported on porous carbon to achieve a Co@150PC catalyst. It exhibits particularly high activity of hydrogen generation with the optimal hydrogen production rate of 11086.4 mL$_{H2}$∙min$^{H2}$∙g$_{Co}$$^{H2}$ and low activation energy (E$_{a}$) of 31.25 kJ mol$^{H2}$. The calculation results based on density functional theory (DFT) indicate that the Co@xPC structure is conducive to the dissociation of [BH$_{4}$]$^{-}$, which effectively enhances the hydrolysis efficiency of NaBH$_4$. Moreover, Co@150PC presents an excellent durability, retaining 72.0% of the initial catalyst activity after 15 cycling tests. Moreover, we also explored the degradation mechanism of catalyst performance

Benchmark Thermochemistry of N-Methylaniline

© 2015 American Chemical Society. In this work, the standard molar enthalpy of formation in the gaseous state of highly pure N-methylaniline, δfHm° (g, 298.15 K) = 90.9 ± 2.1 kJ·mol-1, has been obtained from the calorimetrically measured energy of combustion converted into the enthalpy of formation, δfHm° (liq, 298.15 K) = 35.9 ± 2.1 kJ·mol-1, and from the molar enthalpy of vaporization, δlgHm = 55.0 ± 0.2 kJ·mol-1, derived from vapor pressure measurements by transpiration method. The enthalpy of formation of N-methylaniline calculated using the quantum chemical G4 method was in excellent agreement with the experimental value. The frequencies of normal vibrations were obtained from the experimental and calculated spectra. Thermodynamic properties of N-methylaniline in the ideal gas state were calculated from molecular and spectral data in the temperature range 100-1500 K

Benchmark Thermochemistry of N-Methylaniline

© 2015 American Chemical Society. In this work, the standard molar enthalpy of formation in the gaseous state of highly pure N-methylaniline, δfHm° (g, 298.15 K) = 90.9 ± 2.1 kJ·mol-1, has been obtained from the calorimetrically measured energy of combustion converted into the enthalpy of formation, δfHm° (liq, 298.15 K) = 35.9 ± 2.1 kJ·mol-1, and from the molar enthalpy of vaporization, δlgHm = 55.0 ± 0.2 kJ·mol-1, derived from vapor pressure measurements by transpiration method. The enthalpy of formation of N-methylaniline calculated using the quantum chemical G4 method was in excellent agreement with the experimental value. The frequencies of normal vibrations were obtained from the experimental and calculated spectra. Thermodynamic properties of N-methylaniline in the ideal gas state were calculated from molecular and spectral data in the temperature range 100-1500 K

Benchmark Thermochemistry of N-Methylaniline

© 2015 American Chemical Society. In this work, the standard molar enthalpy of formation in the gaseous state of highly pure N-methylaniline, δfHm° (g, 298.15 K) = 90.9 ± 2.1 kJ·mol-1, has been obtained from the calorimetrically measured energy of combustion converted into the enthalpy of formation, δfHm° (liq, 298.15 K) = 35.9 ± 2.1 kJ·mol-1, and from the molar enthalpy of vaporization, δlgHm = 55.0 ± 0.2 kJ·mol-1, derived from vapor pressure measurements by transpiration method. The enthalpy of formation of N-methylaniline calculated using the quantum chemical G4 method was in excellent agreement with the experimental value. The frequencies of normal vibrations were obtained from the experimental and calculated spectra. Thermodynamic properties of N-methylaniline in the ideal gas state were calculated from molecular and spectral data in the temperature range 100-1500 K

Benchmark thermochemistry of methylbenzonitriles: Experimental and theoretical study

© 2015 Elsevier Ltd. All rights reserved. The gas-phase enthalpies of formation of 2-, 3-, and 4-methylbenzonitrile at T = 298.15 K were studied by combustion calorimetry, and their vaporization enthalpies were determined using the transpiration method. The composite ab initio methods W1-F12 and G4 were used to calculate the gas-phase enthalpies of formation for these three methylbenzonitriles. These theoretical values were found to be in excellent agreement with the corresponding experimental data. The analysis of these data revealed that the interaction between cyano and methyl groups is slightly stabilizing. Using the experimental data a set of group-additivity terms, which allows to estimate thermochemical properties for methyl and cyano substituted benzenes, was proposed. These terms, together with theoretical data, were subsequently used to reassess the thermochemical properties of 2,6-dimethylbenzonitrile and 2,4,6-trimethylbenzonitrile

Benchmark properties of pyrazole derivatives as a potential liquid organic hydrogen carrier: Evaluation of thermochemical data with complementary experimental and computational methods

© 2018 Elsevier Ltd The standard molar enthalpies of vaporization of alkyl-pyrazoles were derived from their vapor pressure–temperature dependence measured by the transpiration method as well as indirectly using solution calorimetry. Thermodynamic data on vaporization processes available in the literature were collected, evaluated, and combined with our own experimental results. Additional combustion experiments on the highly pure 1-methyl-pyrazoles helped to resolve ambiguity in the enthalpy of formation for this compound. We have evaluated and recommended a set of vaporization and formation enthalpies for the alkyl-pyrazoles at 298.15 K as the reliable benchmark properties for further thermochemical calculations. Gas phase molar enthalpies of formation of alkyl-pyrazoles calculated by the high-level quantum-chemical G4 and G3MP2 methods were in an excellent agreement with the recommended experimental data. The hydrogenation/dehydrogenation reaction enthalpies of alkyl-pyrazoles were calculated and compared with the data for other potential liquid organic hydrogen carriers

Benchmark properties of pyrazole derivatives as a potential liquid organic hydrogen carrier: Evaluation of thermochemical data with complementary experimental and computational methods

© 2018 Elsevier Ltd The standard molar enthalpies of vaporization of alkyl-pyrazoles were derived from their vapor pressure–temperature dependence measured by the transpiration method as well as indirectly using solution calorimetry. Thermodynamic data on vaporization processes available in the literature were collected, evaluated, and combined with our own experimental results. Additional combustion experiments on the highly pure 1-methyl-pyrazoles helped to resolve ambiguity in the enthalpy of formation for this compound. We have evaluated and recommended a set of vaporization and formation enthalpies for the alkyl-pyrazoles at 298.15 K as the reliable benchmark properties for further thermochemical calculations. Gas phase molar enthalpies of formation of alkyl-pyrazoles calculated by the high-level quantum-chemical G4 and G3MP2 methods were in an excellent agreement with the recommended experimental data. The hydrogenation/dehydrogenation reaction enthalpies of alkyl-pyrazoles were calculated and compared with the data for other potential liquid organic hydrogen carriers

Benchmark thermochemistry of methylbenzonitriles: Experimental and theoretical study

© 2015 Elsevier Ltd. All rights reserved. The gas-phase enthalpies of formation of 2-, 3-, and 4-methylbenzonitrile at T = 298.15 K were studied by combustion calorimetry, and their vaporization enthalpies were determined using the transpiration method. The composite ab initio methods W1-F12 and G4 were used to calculate the gas-phase enthalpies of formation for these three methylbenzonitriles. These theoretical values were found to be in excellent agreement with the corresponding experimental data. The analysis of these data revealed that the interaction between cyano and methyl groups is slightly stabilizing. Using the experimental data a set of group-additivity terms, which allows to estimate thermochemical properties for methyl and cyano substituted benzenes, was proposed. These terms, together with theoretical data, were subsequently used to reassess the thermochemical properties of 2,6-dimethylbenzonitrile and 2,4,6-trimethylbenzonitrile