The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Peter Walde - One of the best experts on this subject based on the ideXlab platform.
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an esr characterization of micelles and vesicles formed in aqueous Decanoic Acid sodium decanoate systems using different spin labels
Chemistry and Physics of Lipids, 2008Co-Authors: Branka Dejanovic, Slavko Pecar, Marjeta Sentjurc, Krunoslav Mirosavljevic, Vesna Noethiglaslo, Peter WaldeAbstract:Abstract Aqueous Decanoic Acid/sodium decanaote systems were studied as a function of pH and concentration, up to 0.3 M Decanoic Acid/sodium decanoate, by electron spin resonance (ESR) spectroscopy using three different amphiphilic spin labels. The distribution of the spin labels between vesicles and micelles as well as their dynamic properties were determined by quantitative analysis of the ESR spectra using two novel simulation software packages. Rotational correlation time of the labels in micelles was found to increase with decreasing pH, with substantial increase in the region where vesicles were formed (7.8
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An ESR characterization of micelles and vesicles formed in aqueous Decanoic Acid/sodium decanoate systems using different spin labels.
Chemistry and physics of lipids, 2008Co-Authors: Branka Dejanović, Krunoslav Mirosavljević, Vesna Noethig-laslo, Slavko Pecar, Marjeta Sentjurc, Peter WaldeAbstract:Aqueous Decanoic Acid/sodium decanaote systems were studied as a function of pH and concentration, up to 0.3 M Decanoic Acid/sodium decanoate, by electron spin resonance (ESR) spectroscopy using three different amphiphilic spin labels. The distribution of the spin labels between vesicles and micelles as well as their dynamic properties were determined by quantitative analysis of the ESR spectra using two novel simulation software packages. Rotational correlation time of the labels in micelles was found to increase with decreasing pH, with substantial increase in the region where vesicles were formed (7.8
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From decanoate micelles to Decanoic Acid/dodecylbenzenesulfonate vesicles.
Langmuir : the ACS journal of surfaces and colloids, 2005Co-Authors: Trishool Namani, Peter WaldeAbstract:Different aspects of mixtures of Decanoic Acid and sodium decanoate were investigated in aqueous solution up to a total concentration of 300 mM. Depending on the ratio of ionized to nonionized Decanoic Acid, micelles or vesicles form above the critical concentrations of micelle (cmc) or the critical concentration for vesicle formation (cvc). The micelles and the vesicles are always present together with nonmicellized or nonvesiculized decanoate. The latter was determined for different total concentrations. On the basis of titration curves, by application of the Gibbs phase rule, and on the basis of differential scanning calorimetry measurements and an electron microscopy analysis, the pH region within which vesicles exist was identified (pH 6.8−7.8). At pH 7.0, the concentration of nonvesiculized decanoate is ∼20 mM. Decanoic Acid/decanoate vesicles can be sized down by the extrusion technique to form stable and mainly unilamellar vesicles with a mean diameter of less than 100 nm. By coaddition of an equi...
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from decanoate micelles to Decanoic Acid dodecylbenzenesulfonate vesicles
Langmuir, 2005Co-Authors: Trishool Namani, Peter WaldeAbstract:Different aspects of mixtures of Decanoic Acid and sodium decanoate were investigated in aqueous solution up to a total concentration of 300 mM. Depending on the ratio of ionized to nonionized Decanoic Acid, micelles or vesicles form above the critical concentrations of micelle (cmc) or the critical concentration for vesicle formation (cvc). The micelles and the vesicles are always present together with nonmicellized or nonvesiculized decanoate. The latter was determined for different total concentrations. On the basis of titration curves, by application of the Gibbs phase rule, and on the basis of differential scanning calorimetry measurements and an electron microscopy analysis, the pH region within which vesicles exist was identified (pH 6.8−7.8). At pH 7.0, the concentration of nonvesiculized decanoate is ∼20 mM. Decanoic Acid/decanoate vesicles can be sized down by the extrusion technique to form stable and mainly unilamellar vesicles with a mean diameter of less than 100 nm. By coaddition of an equi...
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thermodynamic and kinetic stability properties of micelles and vesicles formed by the Decanoic Acid decanoate system
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2003Co-Authors: Kenichi Morigaki, Peter Walde, Misni Misran, Brian H. RobinsonAbstract:The dialysis of micellar and vesicular systems, through a cellulose acetate membrane permeable only to monomer surfactant, has been investigated for the system sodium decanoate/Decanoic Acid as a function of pH, in pH regions where micelles (pH 9) or vesicles (pH 7.5) are present. The results provide data that are helpful in establishing the thermodynamic state of the systems and the interplay of the relevant equilibrium and kinetic considerations. Additionally, the kinetics of spontaneous formation and destruction of vesicles when subjected to a pH-jump perturbation have been studied. Changes are rapid, taking place over a time scale of a few seconds.
Gary J. Blanchard - One of the best experts on this subject based on the ideXlab platform.
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Investigating internal structural differences between micelles and unilamellar vesicles of Decanoic Acid/sodium decanoate.
The journal of physical chemistry. B, 2006Co-Authors: Sarah A. Stevenson, Gary J. BlanchardAbstract:We report on the dynamics of a chromophore sequestered within the nonpolar regions of micelles and unilamellar vesicles comprised of Decanoic Acid/sodium decanoate. We find that there is a measurable difference in the motional dynamics of the chromophore perylene in these two nonpolar media, with the vesicle structure forming a somewhat less viscous environment than the micelle. In all cases, the chromophore reorients as a prolate rotor, implying a local environment with a nominally similar shape for both micelle and vesicle structures. These findings demonstrate that the organization of micelles is measurably different than that of bilayers.
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investigating internal structural differences between micelles and unilamellar vesicles of Decanoic Acid sodium decanoate
Journal of Physical Chemistry B, 2006Co-Authors: Sarah A. Stevenson, Gary J. BlanchardAbstract:We report on the dynamics of a chromophore sequestered within the nonpolar regions of micelles and unilamellar vesicles comprised of Decanoic Acid/sodium decanoate. We find that there is a measurable difference in the motional dynamics of the chromophore perylene in these two nonpolar media, with the vesicle structure forming a somewhat less viscous environment than the micelle. In all cases, the chromophore reorients as a prolate rotor, implying a local environment with a nominally similar shape for both micelle and vesicle structures. These findings demonstrate that the organization of micelles is measurably different than that of bilayers.
Sylvette Brunet - One of the best experts on this subject based on the ideXlab platform.
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Effect of the presence of ionic liquid during the NiMoS bulk preparation in the transformation of Decanoic Acid
Applied Catalysis A: General, 2017Co-Authors: Géraldine Leyral, Soizic Brillouet, Frederic Richard, Julie Rousseau, Anne-sophie Mamede, Laurence Courthéoux, Annie Pradel, Michel Ribes, Sylvette BrunetAbstract:The impact of the presence and amount of [BMIM][NTf2] ionic liquid during the preparation of bulk NiMoS catalysts was investigated. It was clearly shown that these factors have a strong influence on both the morphology and specific surface area of the obtained NiMoS samples. Most interestingly the catalytic activity for the transformation of Decanoic Acid increased up to three times when IL was present during synthesis. In the same time, a greater selectivity towards hydrocarbons was observed. On the whole a clear relationship between catalytic activity, selectivity and NiMoS morphology was demonstrated. Consequently, it is possible to modify the morphology of the materials and impact the catalytic properties by changing the synthesis conditions.
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Inhibiting effect of Decanoic Acid and its by-products on the transformation of n-hexadecane over a Pt/SiO2-Al2O3 catalyst
Applied Catalysis B: Environmental, 2016Co-Authors: A.s. Guedes, Christophe Bouchy, Sylvette BrunetAbstract:Abstract The impact of Decanoic Acid (a model molecule representative of the most abundant oxygenates present in LTFT syncrude) and its by-products (CO, CO 2 , H 2 O) on the transformation of n -hexadecane was studied over a Pt/Al 2 O 3 -SiO 2 conventional bifunctional catalyst under hydrocracking conditions. An irreversible impact of Decanoic Acid and its by-products (CO and CO 2 , H 2 O) was demonstrated corresponding to a decrease of the activity of the catalyst and a modification of the selectivities towards isomerization and cracking. Water produced by the total transformation of the Acid, CO, CO 2 was identified as the real contaminant whatever the oxygenates. The catalyst selectivities towards isomerization and cracking were modified in favour of isomerization in the presence of low amounts of oxygenates. The balance (Acid and hydro-dehydrogenation properties) of the catalyst was modified corresponding to a decrease of the Acidity of the support and a sintering of the platinum.
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Deoxygenation of Decanoic Acid and its main intermediates over unpromoted and promoted sulfided catalysts
Applied Catalysis B: Environmental, 2014Co-Authors: Soizic Brillouet, Elena Baltag, Sylvette Brunet, Frederic RichardAbstract:The transformation of Decanoic Acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340 degrees C under 4 MPa of total pressure (H-2 pressure equal to 2.72 MPa) in a fixed-bed reactor. The deoxygenation of Decanoic Acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic Acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of Decanoic Acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of Decanoic Acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase.
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Deoxygenation of Decanoic Acid and its main intermediates over unpromoted and promoted sulfided catalysts
Applied Catalysis B: Environmental, 2014Co-Authors: Soizic Brillouet, Elena Baltag, Sylvette Brunet, Frederic RichardAbstract:International audienceThe transformation of Decanoic Acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340 degrees C under 4 MPa of total pressure (H-2 pressure equal to 2.72 MPa) in a fixed-bed reactor. The deoxygenation of Decanoic Acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic Acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of Decanoic Acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of Decanoic Acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase
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Deoxygenation of Decanoic Acid and its main intermediates over unpromoted and promoted sulfided catalysts
Applied Catalysis B-environmental, 2013Co-Authors: Soizic Brillouet, Elena Baltag, Sylvette Brunet, Frederic RichardAbstract:Abstract The transformation of Decanoic Acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340 °C under 4 MPa of total pressure (H2 pressure equal to 2.72 MPa) in a fixed-bed reactor. The deoxygenation of Decanoic Acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic Acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of Decanoic Acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of Decanoic Acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase.
Frederic Richard - One of the best experts on this subject based on the ideXlab platform.
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Effect of the presence of ionic liquid during the NiMoS bulk preparation in the transformation of Decanoic Acid
Applied Catalysis A: General, 2017Co-Authors: Géraldine Leyral, Soizic Brillouet, Frederic Richard, Julie Rousseau, Anne-sophie Mamede, Laurence Courthéoux, Annie Pradel, Michel Ribes, Sylvette BrunetAbstract:The impact of the presence and amount of [BMIM][NTf2] ionic liquid during the preparation of bulk NiMoS catalysts was investigated. It was clearly shown that these factors have a strong influence on both the morphology and specific surface area of the obtained NiMoS samples. Most interestingly the catalytic activity for the transformation of Decanoic Acid increased up to three times when IL was present during synthesis. In the same time, a greater selectivity towards hydrocarbons was observed. On the whole a clear relationship between catalytic activity, selectivity and NiMoS morphology was demonstrated. Consequently, it is possible to modify the morphology of the materials and impact the catalytic properties by changing the synthesis conditions.
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Deoxygenation of Decanoic Acid and its main intermediates over unpromoted and promoted sulfided catalysts
Applied Catalysis B: Environmental, 2014Co-Authors: Soizic Brillouet, Elena Baltag, Sylvette Brunet, Frederic RichardAbstract:The transformation of Decanoic Acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340 degrees C under 4 MPa of total pressure (H-2 pressure equal to 2.72 MPa) in a fixed-bed reactor. The deoxygenation of Decanoic Acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic Acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of Decanoic Acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of Decanoic Acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase.
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Deoxygenation of Decanoic Acid and its main intermediates over unpromoted and promoted sulfided catalysts
Applied Catalysis B: Environmental, 2014Co-Authors: Soizic Brillouet, Elena Baltag, Sylvette Brunet, Frederic RichardAbstract:International audienceThe transformation of Decanoic Acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340 degrees C under 4 MPa of total pressure (H-2 pressure equal to 2.72 MPa) in a fixed-bed reactor. The deoxygenation of Decanoic Acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic Acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of Decanoic Acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of Decanoic Acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase
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Deoxygenation of Decanoic Acid and its main intermediates over unpromoted and promoted sulfided catalysts
Applied Catalysis B-environmental, 2013Co-Authors: Soizic Brillouet, Elena Baltag, Sylvette Brunet, Frederic RichardAbstract:Abstract The transformation of Decanoic Acid, used as a model oxygenated compound, was first studied over Mo/Al2O3 at 340 °C under 4 MPa of total pressure (H2 pressure equal to 2.72 MPa) in a fixed-bed reactor. The deoxygenation of Decanoic Acid is considered to proceed through two main routes: (i) the HDO pathway yielding decenes and decane as ultimate hydrocarbons, oxygen being removed as water; (ii) the DEC pathway involving a decarbonylation reaction and mainly leading to nonene isomers, oxygen being discarded as water and carbon monoxide. Other products such as oygenates (mainly decanal and 1-decanol) and sulfur-containing products (mainly 1-decanethiol) appeared as intermediates of the HDO way. A significant inhibiting effect of carboxylic Acid on the deoxygenation of decanal was highlighted. A general reaction scheme of deoxygenation of Decanoic Acid over sulfided catalysts was established. Considering a sulfur vacancy as an active site, deoxygenation reaction mechanisms were proposed involving a cationic species as a common intermediate between the HDO and the DEC pathways. The effect of Co and Ni on the deoxygenation rate of Decanoic Acid was measured by using both CoMo/Al2O3 and NiMo/Al2O3. The DEC route was strongly promoted by Co and Ni, whereas an inhibiting effect of Co and Ni was observed on the HDO route. It was assumed that the promoter effect on the DEC route may result from an increase of the basicity of sulfur anions neighbouring of Co or Ni present in the sulfided promoted phase.
Yongbo Huang - One of the best experts on this subject based on the ideXlab platform.
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Structure and thermal properties of Decanoic Acid/expanded graphite composite phase change materials
Journal of Thermal Analysis and Calorimetry, 2017Co-Authors: Hua Yan, Qun Wang, Hongtao Wang, Yongbo HuangAbstract:Decanoic Acid/expanded graphite composite phase change materials (DA/EG-PCMs) with high stability and excellent thermal conductivity were fabricated by blending expanded graphite (EG) and Decanoic Acid (DA). The structure, thermo-physical properties, and the formation mechanism of DA/EG-PCMs were investigated. The obtained results demonstrate that EG exhibits a network-like porous structure, which is superimposed of 10–50 μm thick graphite sheet. Therefore, DA can be effectively encapsulated through the binding between micropores and the surface adsorption of EG resulting in a relatively smaller DA/EG-PCMs particle with better dispersibility. In addition, adding EG into DA also increased both the thermal stability and the thermal conductivity while decreasing the charging and discharging time, which resulted in improved thermal efficiencies. Although adding EG can negatively influence the phase change behavior of DA, the temperature and enthalpy of phase change were still as high as 34.9 °C and 153.1 J g−1, respectively. Based on a combination of experimental results and a comprehensive analysis of the phase transformation kinetics, it is concluded that DA/EG-PCMs with 10 mass% EG with improved thermal properties can meet the requirements for efficient temperature control in low-to-medium environments.
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structure and thermal properties of Decanoic Acid expanded graphite composite phase change materials
Journal of Thermal Analysis and Calorimetry, 2017Co-Authors: Hua Yan, Qun Wang, Hongtao Wang, Yongbo HuangAbstract:Decanoic Acid/expanded graphite composite phase change materials (DA/EG-PCMs) with high stability and excellent thermal conductivity were fabricated by blending expanded graphite (EG) and Decanoic Acid (DA). The structure, thermo-physical properties, and the formation mechanism of DA/EG-PCMs were investigated. The obtained results demonstrate that EG exhibits a network-like porous structure, which is superimposed of 10–50 μm thick graphite sheet. Therefore, DA can be effectively encapsulated through the binding between micropores and the surface adsorption of EG resulting in a relatively smaller DA/EG-PCMs particle with better dispersibility. In addition, adding EG into DA also increased both the thermal stability and the thermal conductivity while decreasing the charging and discharging time, which resulted in improved thermal efficiencies. Although adding EG can negatively influence the phase change behavior of DA, the temperature and enthalpy of phase change were still as high as 34.9 °C and 153.1 J g−1, respectively. Based on a combination of experimental results and a comprehensive analysis of the phase transformation kinetics, it is concluded that DA/EG-PCMs with 10 mass% EG with improved thermal properties can meet the requirements for efficient temperature control in low-to-medium environments.
