The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Umpei Nagashima - One of the best experts on this subject based on the ideXlab platform.
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computational study of excited state intramolecular proton transfer of o Hydroxybenzaldehyde and its derivatives
Bulletin of the Chemical Society of Japan, 2009Co-Authors: Shinichi Nagaoka, Hiroyuki Teramae, Umpei NagashimaAbstract:The excited-state intramolecular-proton-transfer of o-Hydroxybenzaldehyde and its derivatives (o-formyl-substituted phenols) was studied by means of an ab initio molecular-orbital method. The compu...
Manuel J.s. Monte - One of the best experts on this subject based on the ideXlab platform.
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Vapor Pressures and Gibbs Energies of Formation of the Three Hydroxybenzaldehydes
Journal of Chemical & Engineering Data, 2017Co-Authors: Ana R.r.p. Almeida, Manuel J.s. MonteAbstract:This work reports experimental sublimation and vaporization vapor pressures at different temperatures of the three isomers of Hydroxybenzaldehyde. A static method based on capacitance diaphragm manometers was used to measure the vapor pressures of both (crystalline and liquid) condensed phases of ortho, meta, and para Hydroxybenzaldehydes, through the temperature ranges T = (264.6 to 341.7) K, T = (324.9 to 419.4) K, and T = (334.9 to 429.4) K, respectively. The Knudsen mass-loss effusion technique was also used to determine the vapor pressures of crystalline meta and para isomers in the temperature intervals T = (309.1 to 331.2) K and T = (319.1 to 341.2) K, respectively. The obtained results enabled the determination of the standard molar enthalpies and entropies of sublimation and of vaporization, at chosen reference temperatures, as well as the (p,T) values of the triple point of the compounds studied. The temperatures and enthalpies of fusion were determined from differential scanning calorimetry. Th...
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thermodynamic study on Hydroxybenzaldehyde derivatives 3 and 4 Hydroxybenzaldehyde isomers and 3 5 di tert butyl 2 Hydroxybenzaldehyde
The Journal of Chemical Thermodynamics, 2010Co-Authors: Maria Ribeiro D M C Da Silva, Mariana V Goncalves, Manuel J.s. MonteAbstract:Reported in the present work are the values of the gaseous standard ( p ∘ = 0.1 MPa ) molar enthalpies of formation of 3-Hydroxybenzaldehyde (3HBA), 4-Hydroxybenzaldehyde (4HBA), and 3,5-di-tert-butyl-2-Hydroxybenzaldehyde (3,5DTBHBA), at T = 298.15 K. For the three compounds, the values were derived from measurements of the standard molar energies of combustion of the crystalline compounds, using a static bomb calorimeter { Δ c H m ∘ ( 3 HBA ) = - ( 3298.3 ± 1.3 ) kJ · mol - 1 , Δ c H m ∘ ( 4 HBA ) = - ( 3291.8 ± 0.9 ) kJ · mol - 1 , Δ c H m ∘ ( 3 , 5 DTBHBA ) = - ( 8502.6 ± 2.9 ) kJ · mol - 1 } , together with the standard molar enthalpies of sublimation, at T = 298.15 K, derived from the vapour pressures measured at different temperatures using the Knudsen effusion technique { Δ cr g H m ∘ ( 3 HBA ) = ( 100.1 ± 0.6 ) kJ · mol - 1 , Δ cr g H m ∘ ( 4 HBA ) = ( 102.5 ± 0.5 ) kJ · mol - 1 , Δ cr g H m ∘ ( 3 , 5 DTBHBA ) = ( 96.0 ± 0.5 ) kJ · mol - 1 } .
Shinichi Nagaoka - One of the best experts on this subject based on the ideXlab platform.
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computational study of excited state intramolecular proton transfer of o Hydroxybenzaldehyde and its derivatives
Bulletin of the Chemical Society of Japan, 2009Co-Authors: Shinichi Nagaoka, Hiroyuki Teramae, Umpei NagashimaAbstract:The excited-state intramolecular-proton-transfer of o-Hydroxybenzaldehyde and its derivatives (o-formyl-substituted phenols) was studied by means of an ab initio molecular-orbital method. The compu...
E H Abdellatiff - One of the best experts on this subject based on the ideXlab platform.
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reaction of crosslinked chloromethylated polystyrene with 4 Hydroxybenzaldehyde under phase transfer catalyzed conditions
Polymer, 1999Co-Authors: A A Sarhan, Magdy Y Abdelaal, E H AbdellatiffAbstract:The present work studied factors which may affect phase transfer-catalyzed (PTC) nucleophilic displacement reactions, including chloromethylated polystyrene as polymer-supported alkylating agent and 4-Hydroxybenzaldehyde as an O-nucleophilic reagent in presence of representatives for phase transfer catalysts. Some polymer-analogue conversions using the resulting polymer-supported aldehyde have been carried out.
J. J. Berzas Nevado - One of the best experts on this subject based on the ideXlab platform.
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First Derivative of the Ratio Spectra Method for Resolving 3‐Hydroxybenzaldehyde and 4‐Hydroxybenzaldehyde in Binary Mixtures
Bulletin des Sociétés Chimiques Belges, 2010Co-Authors: J. J. Berzas Nevado, C. Guiberteau Cabanillas, F. Salinas LópezAbstract:A method for the simultaneous determination of the isomers 3-Hydroxybenzaldehyde and 4-Hydroxybenzaldehyde in binary mixtures is proposed. The method is based on the use of the first derivative of the ratio spectra obtained by dividing the amplitudes, at appropriate wavelengths, of the absorption spectra of the mixtures by a standard of 4-Hydroxybenzaldehyde for determining 3-Hydroxybenzaldehyde and by a standard of 3-Hydroxybenzaldehyde for determining 4-Hydroxybenzaldehyde. The method compares favourably with other spectrophotometric methods.
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spectrophotometric resolution of ternary mixtures of salicylaldehyde 3 Hydroxybenzaldehyde and 4 Hydroxybenzaldehyde by the derivative ratio spectrum zero crossing method
Talanta, 1992Co-Authors: J. J. Berzas Nevado, Guiberteau C Cabanillas, F SalinasAbstract:A new spectrophotometric method for resolving ternary mixtures is proposed. The method is based on the simultaneous use of the first derivative of ratio spectra and measurements of zero-crossing wavelengths. The ratio spectrum is obtained by dividing the amplitudes of the absorption spectrum of the mixture by a standard spectrum of one of the components giving the first derivative of the ratio spectrum. The concentrations of the other components is then determined from their respective calibration graphs established by measuring the ratio derivative analytical signal at the selected zero-crossing points. The method has been applied to resolving ternary mixtures of the isomers salicylaldehyde, 3-Hydroxybenzaldehyde and 4-Hydroxybenzaldehyde. Previously, we also resolved the binary mixture of salicylaldehyde and 3-Hydroxybenzaldehyde. The method compares favourably with other spectrophotometric methods.
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resolution of the binary mixture of salicylaldehyde and 4 Hydroxybenzaldehyde by using first derivative ratio spectra
Analytical Letters, 1990Co-Authors: J. J. Berzas Nevado, Guiberteau C Cabanillas, Salinas F LopezAbstract:Abstract A new spectrophotometric method for simultaneous determination of the isomers salicylaldehyde and 4-Hydroxybenzaldehyde is proposed. Binary mixtures are resolved on the basis of the first derivative of the ratio spectra obtained by dividing the amplitude the salicylaldehyde absorption spectra by a standard spectrum of 4-Hydroxybenzaldehyde for (determining salicylaldehyde) and vice versa for determining 4-Hydroxybenzaldehyde - The method compares favorably with other spectrophotometric methods.
