Degree: Doctor

Affiliation(s):

FCUP

Publications
Showing 5 latest publications. Total publications: 120
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1. Study on the volatility of four benzaldehydes, Almeida, ARRP Pinheiro, BDA; Ferreira, AIMCL Monte, MJS in THERMOCHIMICA ACTA, 2022, ISSN: 0040-6031,  Volume: 717, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.tca.2022.179357 P-00X-9QG
Abstract This work reports the experimental determination of relevant thermodynamic properties of four benzaldehydes. The vapor pressures of both crystalline and liquid phases (including supercooled liquid) of syringaldehyde, 3,4,5-trimethoxybenzaldehyde, 4-(dimethylamino)benzaldehyde and of the liquid phase of veratraldehyde were determined using a static method based on capacitance diaphragm manometers. Additionally, the sublimation vapor pressures of the four compounds were also determined at different temperatures, using the Knudsen mass -loss effusion method. The experimental results allowed accurate determination of the standard molar enthalpies, entropies and Gibbs energies of sublimation and of vaporization for the benzaldehydes studied, at reference temperatures, allowing phase diagram representations of the (p,T) results, in the neighborhood of the triple point of the four compounds. Their temperatures and molar enthalpies of fusion were determined using differential scanning calorimetry and were compared with the ones obtained indirectly through vapor pressure measure-ments. Using high-precision drop calorimetry, the standard isobaric molar heat capacities of the four crystalline benzaldehydes were determined at 298.15 K. The enthalpy of the intermolecular hydrogen bond O-H...O in the crystalline phase of syringaldehyde was estimated.

2. Thermodynamic Properties of Moldy-Musty Contaminants of Wine, Almeida, ARRP Pinheiro, BDA; Lima, CFRAC Santos, AFLOM; Ferreira, ACS; Almeida Paz, FAA; Monte, MJS in JOURNAL OF CHEMICAL AND ENGINEERING DATA, 2019, ISSN: 0021-9568,  Volume: 64, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1021/acs.jced.9b00062 P-00Q-PR5
Abstract This paper reports thermodynamic properties of phase transitions of 2,4,6-trichloro and 2,4,6-tribromo anisoles and of 2,4,6-tribromophenol. The vapor pressures of both crystalline and liquid phases (including supercooled liquid) of the three compounds were measured, respectively, in the temperature ranges T = (297.1 to 368.3) K, T = (330.7 to 391.7) K, and T = (336.5 to 401.7) K, using a static method based on capacitance diaphragm manometers. Moreover, the sublimation vapor pressures of 2,4,6-tribromophenol were also measured in the temperature interval (307.2 to 329.2) K, using a Knudsen mass-loss effusion technique. The standard molar enthalpies, entropies, and Gibbs energies of sublimation and of vaporization, at reference temperatures, were derived from the experimental results as well as the (p,T) values of the triple point of each compound. The temperatures and molar enthalpies of fusion of the three benzene derivatives were determined using differential scanning calorimetry and were compared with the values derived indirectly from the vapor pressure measurements. The thermodynamic results were discussed together with the available literature data for 2,4,6-trichlorophenol. To help rationalize the phase behavior of these substances, the crystallographic structure of 2,4,6-tribromophenol was determined by single crystal X-ray diffraction.

3. Volatility and thermodynamic stability of vanillin, Almeida, ARRP Freitas, VLS Campos, JIS; Ribeiro da Silva, MDMCR Monte, MJS in JOURNAL OF CHEMICAL THERMODYNAMICS, 2019, ISSN: 0021-9614,  Volume: 128, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.jct.2018.07.023 P-00P-G83
Abstract Vanillin is a naturally occurring phenolic aldehyde that is world-wide known for its flavouring properties. This work reports an extensive experimental and computational study of its thermodynamic properties. The vapour pressures of crystalline and liquid phases of vanillin were measured in the following temperature ranges T = (321.0-350.7) K and (324.9-382.3) K respectively, using a static method based on diaphragm capacitance gauge. Additionally, the crystalline vapour pressures were also measured in the temperature interval T = (303.1-325.2) K, using a Knudsen mass-loss effusion technique. The standard molar enthalpies, entropies and Gibbs energies of sublimation and of vaporization, at selected reference temperatures, were derived from the vapour pressure measurements. The enthalpies of vaporization and of sublimation, at T = 298.15 K, were also determined using Calvet microcalorimetry and the standard (p degrees = 10(5) Pa) molar enthalpy of formation, in the crystalline phase, at T = 298.15 K, was derived from its standard massic energy of combustion measured by static-bomb combustion calorimetry. From the experimental results, the standard molar enthalpy of formation in the gaseous phase, at T = 298.15 K, was calculated and compared with the values estimated by employing quantum chemical calculations. To analyse the thermodynamic stability of vanillin, the standard Gibbs energies of formation in crystalline and gaseous phases were calculated. The molar enthalpy of fusion determined using DSC is compared with indirect results determined using Calvet microcalorimetry and vapour pressure measurements. (C) 2018 Elsevier Ltd.

4. Vapour pressures and thermodynamic stability of the three aminophenol isomers, Almeida, ARRP Notario, R; Monte, MJS in JOURNAL OF CHEMICAL THERMODYNAMICS, 2019, ISSN: 0021-9614,  Volume: 129, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.jct.2018.09.011 P-00P-PR8
Abstract The Knudsen mass-loss effusion method was used to determine the sublimation vapour pressures, at different temperatures, of ortho and para aminophenols in the temperature intervals T = (321.1 to 343.3) K and T= (337.2 to 359.2) K, respectively. The vapour pressures of crystalline meta-aminophenol were measured using the referred to above technique, between (321.4 and 343.3) K, and a static method, based on capacitance diaphragm manometers, between (354.4 and 391.8) K. The latter technique was also used to measure the liquid vapour pressures of this isomer over the temperature range T = (370.0 to 423.3) K. The experimental results enabled the determination of the standard (p(0) = 0.1 MPa) molar enthalpies, entropies and Gibbs energies of sublimation, at T = 298.15 K, of the three compounds, and of vaporization of the meta isomer. The standard enthalpies of formation in the gaseous phase were calculated using quantum chemical calculations and also by combining literature results of enthalpies of formation in the crystalline phase with the sublimation enthalpies results determined in this work. Gas-phase absolute entropies and heat capacities of the three compounds studied were also calculated using theoretical methods. The standard Gibbs energies of formation in crystalline and gaseous phases were determined and used to evaluate the thermodynamic stability of the three isomers in standard conditions. DSC analysis enabled the determination of the temperature and molar enthalpies of fusion of the compounds studied. (C) 2018 Elsevier Ltd.

5. Thermodynamic properties of phase transitions of phenyl derivatives of maleic anhydride and oxazole, Oliveira, JASA; Morais, VMF; Monte, MJS in JOURNAL OF CHEMICAL THERMODYNAMICS, 2019, ISSN: 0021-9614,  Volume: 131, 
Article,  Indexed in: crossref, scopus, wos  DOI: 10.1016/j.jct.2018.12.001 P-00Q-2YK
Abstract An experimental study of the vapour pressures and related thermodynamic properties of three phenyl derivatives of maleic anhydride and oxazole is reported. The vapour pressures of the crystalline phase of these compounds were measured at different temperatures using the Knudsen mass-loss effusion method, enabling the determination of the standard (p degrees = 0.1 MPa) molar enthalpies, entropies and Gibbs energies of sublimation. The enthalpies and temperatures of fusion were determined from DSC experiments. Quantum chemical calculations were used to calculate gas-phase isobaric heat capacities and absolute entropies. (C) 2018 Elsevier Ltd.