Vapor pressures and thermophysical properties of selected ethanolamines

A thermodynamic study of three ethanolamines, 2-(diethylamino)ethanol, 2-(ethylamino)ethanol and 2- (isopropylamino)ethanol, reporting the measurements of vapor pressure, liquid phase heat capacities, and phase behavior is presented in this work. The vapor pressures were measured using a static method in the temperature interval 238e343 K. After a critical assessment of literature data, selected experimental data were correlated using the Cox equation. The liquid phase heat capacities were measured in the temperature range 265e355 K using Tian-Calvet calorimetry and the phase behavior was investigated using differential scanning calorimetry (DSC) starting from 183 K. For 2-(ethylamino)ethanol and 2-(isopropylamino)ethanol, two monotropically related crystalline forms were identified. To our knowledge, vapor pressure and heat capacity for 2-(isopropylamino)ethanol and phase behavior data for 2-(ethylamino)ethanol and 2-(isopropylamino)ethanol are reported for the first time in this work.The authors acknowledge financial support from the Czech Science Foundation (GACR no. 17-03875S) and the project POCI-01- 0145-FEDER-006984 e Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) e and by Portuguese national funds through FCT - Fundação para a Ciência e a TecnologiaThe authors acknowledge financial support from the Czech Science Foundation (GACR no. 17-03875S) and the project POCI-01- 0145-FEDER-006984 e Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) e and by Portuguese national funds through FCT - Fundação para a Ciência e a Tecnologia.info:eu-repo/semantics/publishedVersio

Vapor pressure and thermophysical properties of eugenol and (+)-carvone

In this work, vapor pressures, liquid-phase heat capacities, and phase behavior of two monoterpenoids, (þ)-carvone and eugenol were studied. The vapor pressure experiments were performed using a static method over an environmentally relevant range of temperatures, from 258 K to 308 K. Liquid-phase heat capacities were measured by Tian-Calvet calorimetry between 265 K and 355 K. The phase behavior was investigated by heat-flux differential scanning calorimetry from 183 K. Experimental data were supplemented by ideal-gas thermodynamic properties obtained by combining quantum chemical and statistical thermodynamic calculations. Vapor pressures and heat capacities obtained in this work along with selected literature values were treated simultaneously by multi-property correlation in order to obtain a consistent description of thermodynamically linked properties. To our knowledge, liquid-phase heat capacities and phase behavior of eugenol are reported for the first time in this work.The authors M.F., K.R., V. S., and V.P. acknowledge financial support from the Czech Science Foundation (GACR no. 17-03875S) and specific university research (MSMT No. 20-SVV/2018). The authors S.M.V., O.F., and S.P.P. acknowledge financial support from the project POCI-01-0145-FEDER-006984 e Associate Laboratory LSRE-LCM (UID/EQU/50020/2019) funded by national funds through FCT/MCTES (PIDDAC). S.M.V. also acknowledges FCT for his PhD grant (SFRH/BD/138149/2018).info:eu-repo/semantics/publishedVersio

Heat Capacities of L-Cysteine, L-Serine, L-Threonine, L-Lysine, and L-Methionine

In an effort to establish reliable thermodynamic data for amino acids, heat capacity and phase behavior are reported for L-cysteine (CAS RN: 52-90-4), L-serine (CAS RN: 56-45-1), L-threonine (CAS RN: 72-19-5), L-lysine (CAS RN: 56-87-1), and L-methionine (CAS RN: 63-68-3). Prior to heat capacity measurements, initial crystal structures were identified by X-ray powder diffraction, followed by a thorough investigation of the polymorphic behavior using differential scanning calorimetry in the temperature range from 183 K to the decomposition temperature determined by thermogravimetric analysis. Crystal heat capacities of all five amino acids were measured by Tian–Calvet calorimetry in the temperature interval (262–358) K and by power compensation DSC in the temperature interval from 215 K to over 420 K. Experimental values of this work were compared and combined with the literature data obtained with adiabatic calorimetry. Low-temperature heat capacities of L-threonine and L-lysine, for which no or limited literature data was available, were measured using the relaxation (heat pulse) calorimetry. As a result, reference heat capacities and thermodynamic functions for the crystalline phase from near 0 K to over 420 K were developed

Thermodynamic Study of <i>N</i>-Methylformamide and <i>N</i>,<i>N</i>-Dimethyl-Formamide

An extensive thermodynamic study of N-methylformamide (CAS RN: 123-39-7) and N,N-dimethylformamide (CAS RN: 68-12-2), is presented in this work. The liquid heat capacities of N-methylformamide were measured by Tian–Calvet calorimetry in the temperature interval (250–300) K. The vapor pressures for N-methylformamide and N,N-dimethylformamide were measured using static method in the temperature range 238 K to 308 K. The ideal-gas thermodynamic properties were calculated using a combination of the density functional theory (DFT) and statistical thermodynamics. A consistent thermodynamic description was developed using the method of simultaneous correlation, where the experimental and selected literature data for vapor pressures, vaporization enthalpies, and liquid phase heat capacities and the calculated ideal-gas heat capacities were treated together to ensure overall thermodynamic consistency of the results. The resulting vapor pressure equation is valid from the triple point to the normal boiling point temperature

Vapor pressures and thermophysical properties of selected monoterpenoids

International audienceA thermodynamic study of selected monoterpenoids, geraniol, β-citronellol, and borneol, is presented in this work. The vapor pressure measurements were performed using two static apparatus over a wide temperature range from 273 to 363 K. Liquid heat capacities were measured by Tian–Calvet calorimetry in the temperature interval from 258 to 355 K. The phase behavior was investigated by DSC from 183 K. The thermodynamic properties in the ideal-gas state were calculated by combining statistical thermodynamics and density functional theory (DFT) calculations. Calculated ideal-gas heat capacities and experimental data on vapor pressure and condensed phase heat capacity were treated simultaneously to obtain a consistent thermodynamic description

Thermodynamic Properties of Stoichiometric Non-Superconducting Phase Y2BaCuO5

Y2BaCuO5 often occurs as an accompanying phase of the well-known high-temperature superconductor YBa2Cu3O7 (also known as YBCO). Y2BaCuO5, easily identifiable due to its characteristic green coloration, is often referred to as &lsquo;green phase&rsquo; or &lsquo;Y-211&rsquo;. In this contribution, Y2BaCuO5 phase was studied in detail with a focus on its thermal and thermodynamic properties. Energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed in the study of sample&rsquo;s morphology and chemical composition. XRD data were further analyzed and lattice parameters refined by Rietveld analysis. Simultaneous thermal analysis was employed to study thermal stability. Particle size distribution was analyzed by laser diffraction. Finally, thermodynamic properties, namely heat capacity and relative enthalpy, were measured by drop calorimetry, differential scanning calorimetry (DSC), and physical properties measurement system (PPMS). Enthalpy of formation was assessed from ab-initio DFT calculations