The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Mariana Teodorescu - One of the best experts on this subject based on the ideXlab platform.
-
Calorimetric study of the selected nitroalkane+chloroalkane binary systems
Journal of Thermal Analysis and Calorimetry, 2014Co-Authors: Mariana Teodorescu, Sara Maxia, Marianna Usula, Bruno Marongiu, Alessandra Piras, Silvia PorceddaAbstract:Excess enthalpies, H ^E, at 298.15 K and atmospheric pressure determined for 12 binary liquid mixtures containing nitromethane or Nitroethane+1-chlorobutane, +1-chloropentane, +1-chlorohexane, +1,2-dichloroethane, +1,3-dichloropropane, and +1,4-dichlorobutane by means of a flow 2277-LKB microcalorimeter, are reported on over composition range. The experimental results, along with the literature data on vapor–liquid equilibrium (VLE), excess Gibbs energies, G ^E, and activity coefficients at infinite dilution, $$ \gamma_{\text{i}}^{\infty } $$ γ i ∞ , are interpreted in terms of DISQUAC group contribution model. The systems are characterized by three types of contact surface: nitro (NO_2), chlorine (Cl), and alkyl (CH_3, CH_2). The interchange energy parameters of the alkyl/NO_2 and alkyl/Cl contacts were determined independently from the study of alkane+nitroalkane and alkane+chloroalkane systems. The structure-dependent interchange parameters of the NO_2/Cl contact are reported in this work. The model provides a fairly consistent description of the VLE and of thermodynamic functions G ^E, H ^E, $$ \gamma_{\text{i}}^{\infty } $$ γ i ∞ , for all investigated mixtures.
-
calorimetric study of the selected nitroalkane chloroalkane binary systems
Journal of Thermal Analysis and Calorimetry, 2014Co-Authors: Mariana Teodorescu, Sara Maxia, Marianna Usula, Bruno Marongiu, Alessandra Piras, Silvia PorceddaAbstract:Excess enthalpies, HE, at 298.15 K and atmospheric pressure determined for 12 binary liquid mixtures containing nitromethane or Nitroethane+1-chlorobutane, +1-chloropentane, +1-chlorohexane, +1,2-dichloroethane, +1,3-dichloropropane, and +1,4-dichlorobutane by means of a flow 2277-LKB microcalorimeter, are reported on over composition range. The experimental results, along with the literature data on vapor–liquid equilibrium (VLE), excess Gibbs energies, GE, and activity coefficients at infinite dilution, \( \gamma_{\text{i}}^{\infty } \), are interpreted in terms of DISQUAC group contribution model. The systems are characterized by three types of contact surface: nitro (NO2), chlorine (Cl), and alkyl (CH3, CH2). The interchange energy parameters of the alkyl/NO2 and alkyl/Cl contacts were determined independently from the study of alkane+nitroalkane and alkane+chloroalkane systems. The structure-dependent interchange parameters of the NO2/Cl contact are reported in this work. The model provides a fairly consistent description of the VLE and of thermodynamic functions GE, HE, \( \gamma_{\text{i}}^{\infty } \), for all investigated mixtures.
-
Refractive Indices Measurement and Correlation for Selected Binary Systems of Various Polarities at 25 °C
Journal of Solution Chemistry, 2013Co-Authors: Mariana Teodorescu, Catinca SecuianuAbstract:New refractive indices at 25 °C were measured and are reported here for 19 binary mixtures of pentan-3-one+1,2-dichloroethane, +1,3-dichloropropane, +1,4-dichlorobutane, +trichloromethane, +1,1,1-trichloroethane, +1,1,2,2-tetrachloroethane; cyclopentanone+1-chlorobutane, +1,1,2,2-tetrachloroethane; cyclohexanone+1,1,2,2-tetrachloroethane; 5-chloro-2-pentanone+ n -hexane, +toluene, +ethylbenzene; nitromethane+trichloromethane; and nitromethane or Nitroethane, +1,2-dichloroethane, +1,3-dichloropropane, +1,4-dichlorobutane. The experimental refractive index deviations from linear mixing behavior have been evaluated and correlated consistently with the 3-parameter Redlich–Kister equation with good results. The molar refraction was also examined for the systems including pentan-3-one, cyclopentanone, cyclohexanone and 5-chloro-2-pentanone for which densities and excess molar volumes are available from previous works. Different theoretical ( n , ρ ) mixing rules were tested for these systems. The excess Gibbs energy G ^E and excess enthalpy H ^E values were considered together with the excess molar volumes V ^E, excess refractive indexes $$ n_{\text{D}}^{\text{E}} $$ n D E , molar refraction R and excess molar refractions R ^E on mixing in the discussion of the influence of the alkyl chain length or of the nature of the second component in the mixture in terms of molecular interactions.
-
isothermal vapor liquid equilibria and excess gibbs free energies in some binary nitroalkane chloroalkane mixtures at temperatures from 298 15k to 318 15k
Fluid Phase Equilibria, 2013Co-Authors: Dana Dragoescu, Mariana Teodorescu, Daniela GheorgheAbstract:Abstract The vapor pressures of binary mixtures of cloroalkane (1-chlorobutane, 1-chloropentane) + nitromethane or Nitroethane were measured at temperatures between 298.15 K and 318.15 K. The vapor pressures vs. liquid phase composition data have been used to calculate the activity coefficients of the two components, and the excess molar Gibbs energies GE for the mixtures, using Barker's method. Redlich–Kister, Wilson, NRTL and UNIQUAC equations, taking into account the vapor phase imperfection in terms of the 2-nd virial coefficient, have represented the GE values. No significant difference between GE values obtained with these equations has been observed. The results indicate that all the systems show positive deviations from Raoult's law. The experimental VLE data were analyzed in terms of the modified UNIFAC (Dortmund) model.
-
isothermal vapour liquid equilibria for nitromethane or Nitroethane 1 4 dichlorobutane binary systems at temperatures between 343 15 and 363 15 k
The Journal of Chemical Thermodynamics, 2013Co-Authors: Mariana Teodorescu, Dana Dragoescu, Daniela GheorgheAbstract:Isothermal vapor–liquid equilibrium (VLE) data are reported at three temperatures, (343.15, 353.15, and 363.15) K, for the binary mixtures containing nitromethane or Nitroethane with 1,3-dichloropropane. For the measurements an all-glass ebulliometer was used, which allows sampling from both phases in equilibrium. The experimental data were correlated using the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) excess Gibbs energy models by means of maximum likelihood method, taking into account the vapor phase imperfection in terms of the second virial coefficients. Both systems are azeotropic and show positive deviations from ideal behavior. The experimental VLE data are analyzed in terms of the modified UNIFAC (Do) model.
Andrew V. Teplyakov - One of the best experts on this subject based on the ideXlab platform.
-
adsorption and thermal chemistry of Nitroethane on si 100 2 1
Journal of Physical Chemistry B, 2003Co-Authors: Semyon Bocharov, And Anna T. Mathauser, Andrew V. TeplyakovAbstract:Surface chemistry of Nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR−FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of Nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of Nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups...
-
Adsorption and Thermal Chemistry of Nitroethane on Si(100)-2 × 1
The Journal of Physical Chemistry B, 2003Co-Authors: Semyon Bocharov, And Anna T. Mathauser, Andrew V. TeplyakovAbstract:Surface chemistry of Nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR−FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of Nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of Nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups...
Semyon Bocharov - One of the best experts on this subject based on the ideXlab platform.
-
adsorption and thermal chemistry of Nitroethane on si 100 2 1
Journal of Physical Chemistry B, 2003Co-Authors: Semyon Bocharov, And Anna T. Mathauser, Andrew V. TeplyakovAbstract:Surface chemistry of Nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR−FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of Nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of Nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups...
-
Adsorption and Thermal Chemistry of Nitroethane on Si(100)-2 × 1
The Journal of Physical Chemistry B, 2003Co-Authors: Semyon Bocharov, And Anna T. Mathauser, Andrew V. TeplyakovAbstract:Surface chemistry of Nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR−FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of Nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of Nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups...
Hong-min Liu - One of the best experts on this subject based on the ideXlab platform.
-
the henry reaction of 1r 1 4 3 6 dianhydro d mannitol 2 yl 1 4 3 6 dianhydro d fructose 5 5 dinitrate different reactive features of nitromethane to Nitroethane
Carbohydrate Research, 2009Co-Authors: Feng-wu Liu, Zhen-ji Wang, Xiao-ping Song, Sai-yang Zhang, Hong-min LiuAbstract:Henry reactions of a novel higher sugar derivative, (1R)-(1,4:3,6-dianhydro-D-mannitol-2-yl)-1,4:3,6-dianhydro-D-fructose 5,5'-dinitrate (Alternate nomenclature: (1R)-(isomannid-2-yl)-1,4:3,6-dianhydro-D-fructose 5,5'-dinitrate), with nitromethane and Nitroethane were studied. The kinetic and thermodynamic reactions with nitromethane under different conditions were carried out to afford (2S)- and (2R)-beta-nitroalcohols, respectively. But when using Nitroethane the reaction gave a (2S)-beta-nitroalcohol with an inverted configuration at vicinal carbon C-1. Two stereogenic centers were generated, and one was altered in the reaction.
-
The Henry reaction of (1R)-(1,4:3,6-dianhydro-d-mannitol-2-yl)-1,4:3,6-dianhydro-d-fructose 5,5′-dinitrate. Different reactive features of nitromethane to Nitroethane
Carbohydrate research, 2009Co-Authors: Feng-wu Liu, Zhen-ji Wang, Xiao-ping Song, Sai-yang Zhang, Hong-min LiuAbstract:Henry reactions of a novel higher sugar derivative, (1R)-(1,4:3,6-dianhydro-D-mannitol-2-yl)-1,4:3,6-dianhydro-D-fructose 5,5'-dinitrate (Alternate nomenclature: (1R)-(isomannid-2-yl)-1,4:3,6-dianhydro-D-fructose 5,5'-dinitrate), with nitromethane and Nitroethane were studied. The kinetic and thermodynamic reactions with nitromethane under different conditions were carried out to afford (2S)- and (2R)-beta-nitroalcohols, respectively. But when using Nitroethane the reaction gave a (2S)-beta-nitroalcohol with an inverted configuration at vicinal carbon C-1. Two stereogenic centers were generated, and one was altered in the reaction.
And Anna T. Mathauser - One of the best experts on this subject based on the ideXlab platform.
-
adsorption and thermal chemistry of Nitroethane on si 100 2 1
Journal of Physical Chemistry B, 2003Co-Authors: Semyon Bocharov, And Anna T. Mathauser, Andrew V. TeplyakovAbstract:Surface chemistry of Nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR−FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of Nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of Nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups...
-
Adsorption and Thermal Chemistry of Nitroethane on Si(100)-2 × 1
The Journal of Physical Chemistry B, 2003Co-Authors: Semyon Bocharov, And Anna T. Mathauser, Andrew V. TeplyakovAbstract:Surface chemistry of Nitroethane on Si(100)-2 × 1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR−FTIR), Auger electron spectroscopy (AES), and thermal desorption mass spectrometry. Molecular adsorption of Nitroethane at submonolayer coverages dominates at cryogenic temperatures (95 K). As the surface temperature is increased to 140 K, chemical reaction involving nitro group occurs, whereas the ethyl entity remains intact. Similar behavior is observed for nitromethane. Thus, a barrier of approximately 36 kJ/mol is established for the interaction of nitroalkane molecules with the Si(100)-2 × 1 surface in contrast to the essentially barrierless transformation predicted previously theoretically for nitromethane. Further annealing of the silicon surface leads to the decomposition of Nitroethane. The concentration of nitrogen and oxygen remains constant on a surface within the temperature interval studied here, whereas approximately half of the ethyl groups...
