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Xuhong Guo - One of the best experts on this subject based on the ideXlab platform.

  • effect of aromatic and aliphatic pendants in poly maleic acid amide co vinyl acetate on asphaltene Precipitation in heavy oil
    Industrial & Engineering Chemistry Research, 2018
    Co-Authors: Run Zou, Decheng Gai, Pascal Theil, Linda Pickenbach, Martien Cohen A Stuart, Xuhong Guo
    Abstract:

    Asphaltene Precipitation often brings difficulties to the recovery and transportation of heavy crude oil. Poly(maleic acid amide-co-vinyl acetate) copolymers with various aromatic (phenyl, naphthyl, and benzimidazole) pendants and/or aliphatic (octyl, tetradecyl, and octadecyl) grafts were synthesized and found to be capable of dispersing asphaltenes effectively. To study the influence of aromatic and aliphatic pendants in copolymers on asphaltene Precipitation behaviors, the initial Precipitation Point, turbidity, and size of asphaltene precipitates from model heavy oils in the presence and absence of copolymers were determined by UV–vis spectroscopy, turbidity meter, and dynamic light scattering, respectively. The effect of copolymers on the viscosity of Tahe heavy oil with high asphaltene content was investigated by the rheological approach. The results revealed that the copolymers with both aromatic and aliphatic pendants dispersed asphaltene, reduced its precipitates, and thus improved the flowabilit...

  • Effect of Aromatic and Aliphatic Pendants in Poly(maleic acid amide-co-vinyl acetate) on Asphaltene Precipitation in Heavy Oil
    2018
    Co-Authors: Run Zou, Decheng Gai, Pascal Theil, Linda Pickenbach, Martien Cohen A Stuart, Xuhong Guo
    Abstract:

    Asphaltene Precipitation often brings difficulties to the recovery and transportation of heavy crude oil. Poly­(maleic acid amide-co-vinyl acetate) copolymers with various aromatic (phenyl, naphthyl, and benzimidazole) pendants and/or aliphatic (octyl, tetradecyl, and octadecyl) grafts were synthesized and found to be capable of dispersing asphaltenes effectively. To study the influence of aromatic and aliphatic pendants in copolymers on asphaltene Precipitation behaviors, the initial Precipitation Point, turbidity, and size of asphaltene precipitates from model heavy oils in the presence and absence of copolymers were determined by UV–vis spectroscopy, turbidity meter, and dynamic light scattering, respectively. The effect of copolymers on the viscosity of Tahe heavy oil with high asphaltene content was investigated by the rheological approach. The results revealed that the copolymers with both aromatic and aliphatic pendants dispersed asphaltene, reduced its precipitates, and thus improved the flowability of Tahe heavy oil more effectively than those with only aromatic or aliphatic graft. The combination of “π–π delocalized conjugation attraction” from aromatic pendants and “steric blocking” from aliphatic grafts should be the reason

Rodrigo Gabriel Simas - One of the best experts on this subject based on the ideXlab platform.

  • study of the polyribosyl ribitol phosphate Precipitation mechanism by salts and organic solvents
    International Journal of Biological Macromolecules, 2019
    Co-Authors: Rodrigo Gabriel Simas, Mickie Takagi, Everson Alves Miranda
    Abstract:

    Abstract Precipitation has been widely applied to purification and fractionation of biological macromolecules. Several physical-chemical factors contribute to the destabilization of those solutions, such as the nature of solvent employed, presence of salts, temperature, and concentration of the macromolecule. In the case of charged biopolymers, electrostatic forces are the major contributors to their stability in solution. However, the role of each variable and the exact mechanism of Precipitation are not completely understood yet. The aim of this work was to study the Precipitation of polyribosyl-ribitol-phosphate (PRP, a linear homogeneous anionic biopolymer) in presence of salts and non-solvents, in order to contribute to the elucidation of its Precipitation mechanism. The solvents tested (acetone, ethanol, and isopropanol) presented distinct dielectric constants. The salts used (NH4Cl, NaCl, KCl, MgCl2, and CaCl2) differ by their cations. For each salt concentration, the solvent fraction that induces Precipitation was identified and the dielectric constant of the bulk solution was calculated. Precipitation always occurred at well-defined combinations of solvents and salts. At low concentration of monovalent salts, there was a linear correlation between the logarithm of the salt concentration and the inverse of the medium dielectric constant at a defined Precipitation Point. This is a strong indication that the stability of the solution depends almost exclusively on the balance of electrostatic forces. This behavior is compatible with the DLVO modeling of colloidal systems. When divalent salts were used, low concentrations of the counterion were sufficient to induce Precipitation, due to a phenomenon called ionic condensation. Apparently, PRP precipitates when around 90% of its charges are neutralized, value that is similar to charge neutralization for DNA Precipitation.

Everson Alves Miranda - One of the best experts on this subject based on the ideXlab platform.

  • study of the polyribosyl ribitol phosphate Precipitation mechanism by salts and organic solvents
    International Journal of Biological Macromolecules, 2019
    Co-Authors: Rodrigo Gabriel Simas, Mickie Takagi, Everson Alves Miranda
    Abstract:

    Abstract Precipitation has been widely applied to purification and fractionation of biological macromolecules. Several physical-chemical factors contribute to the destabilization of those solutions, such as the nature of solvent employed, presence of salts, temperature, and concentration of the macromolecule. In the case of charged biopolymers, electrostatic forces are the major contributors to their stability in solution. However, the role of each variable and the exact mechanism of Precipitation are not completely understood yet. The aim of this work was to study the Precipitation of polyribosyl-ribitol-phosphate (PRP, a linear homogeneous anionic biopolymer) in presence of salts and non-solvents, in order to contribute to the elucidation of its Precipitation mechanism. The solvents tested (acetone, ethanol, and isopropanol) presented distinct dielectric constants. The salts used (NH4Cl, NaCl, KCl, MgCl2, and CaCl2) differ by their cations. For each salt concentration, the solvent fraction that induces Precipitation was identified and the dielectric constant of the bulk solution was calculated. Precipitation always occurred at well-defined combinations of solvents and salts. At low concentration of monovalent salts, there was a linear correlation between the logarithm of the salt concentration and the inverse of the medium dielectric constant at a defined Precipitation Point. This is a strong indication that the stability of the solution depends almost exclusively on the balance of electrostatic forces. This behavior is compatible with the DLVO modeling of colloidal systems. When divalent salts were used, low concentrations of the counterion were sufficient to induce Precipitation, due to a phenomenon called ionic condensation. Apparently, PRP precipitates when around 90% of its charges are neutralized, value that is similar to charge neutralization for DNA Precipitation.

Run Zou - One of the best experts on this subject based on the ideXlab platform.

  • effect of aromatic and aliphatic pendants in poly maleic acid amide co vinyl acetate on asphaltene Precipitation in heavy oil
    Industrial & Engineering Chemistry Research, 2018
    Co-Authors: Run Zou, Decheng Gai, Pascal Theil, Linda Pickenbach, Martien Cohen A Stuart, Xuhong Guo
    Abstract:

    Asphaltene Precipitation often brings difficulties to the recovery and transportation of heavy crude oil. Poly(maleic acid amide-co-vinyl acetate) copolymers with various aromatic (phenyl, naphthyl, and benzimidazole) pendants and/or aliphatic (octyl, tetradecyl, and octadecyl) grafts were synthesized and found to be capable of dispersing asphaltenes effectively. To study the influence of aromatic and aliphatic pendants in copolymers on asphaltene Precipitation behaviors, the initial Precipitation Point, turbidity, and size of asphaltene precipitates from model heavy oils in the presence and absence of copolymers were determined by UV–vis spectroscopy, turbidity meter, and dynamic light scattering, respectively. The effect of copolymers on the viscosity of Tahe heavy oil with high asphaltene content was investigated by the rheological approach. The results revealed that the copolymers with both aromatic and aliphatic pendants dispersed asphaltene, reduced its precipitates, and thus improved the flowabilit...

  • Effect of Aromatic and Aliphatic Pendants in Poly(maleic acid amide-co-vinyl acetate) on Asphaltene Precipitation in Heavy Oil
    2018
    Co-Authors: Run Zou, Decheng Gai, Pascal Theil, Linda Pickenbach, Martien Cohen A Stuart, Xuhong Guo
    Abstract:

    Asphaltene Precipitation often brings difficulties to the recovery and transportation of heavy crude oil. Poly­(maleic acid amide-co-vinyl acetate) copolymers with various aromatic (phenyl, naphthyl, and benzimidazole) pendants and/or aliphatic (octyl, tetradecyl, and octadecyl) grafts were synthesized and found to be capable of dispersing asphaltenes effectively. To study the influence of aromatic and aliphatic pendants in copolymers on asphaltene Precipitation behaviors, the initial Precipitation Point, turbidity, and size of asphaltene precipitates from model heavy oils in the presence and absence of copolymers were determined by UV–vis spectroscopy, turbidity meter, and dynamic light scattering, respectively. The effect of copolymers on the viscosity of Tahe heavy oil with high asphaltene content was investigated by the rheological approach. The results revealed that the copolymers with both aromatic and aliphatic pendants dispersed asphaltene, reduced its precipitates, and thus improved the flowability of Tahe heavy oil more effectively than those with only aromatic or aliphatic graft. The combination of “π–π delocalized conjugation attraction” from aromatic pendants and “steric blocking” from aliphatic grafts should be the reason

Martien Cohen A Stuart - One of the best experts on this subject based on the ideXlab platform.

  • effect of aromatic and aliphatic pendants in poly maleic acid amide co vinyl acetate on asphaltene Precipitation in heavy oil
    Industrial & Engineering Chemistry Research, 2018
    Co-Authors: Run Zou, Decheng Gai, Pascal Theil, Linda Pickenbach, Martien Cohen A Stuart, Xuhong Guo
    Abstract:

    Asphaltene Precipitation often brings difficulties to the recovery and transportation of heavy crude oil. Poly(maleic acid amide-co-vinyl acetate) copolymers with various aromatic (phenyl, naphthyl, and benzimidazole) pendants and/or aliphatic (octyl, tetradecyl, and octadecyl) grafts were synthesized and found to be capable of dispersing asphaltenes effectively. To study the influence of aromatic and aliphatic pendants in copolymers on asphaltene Precipitation behaviors, the initial Precipitation Point, turbidity, and size of asphaltene precipitates from model heavy oils in the presence and absence of copolymers were determined by UV–vis spectroscopy, turbidity meter, and dynamic light scattering, respectively. The effect of copolymers on the viscosity of Tahe heavy oil with high asphaltene content was investigated by the rheological approach. The results revealed that the copolymers with both aromatic and aliphatic pendants dispersed asphaltene, reduced its precipitates, and thus improved the flowabilit...

  • Effect of Aromatic and Aliphatic Pendants in Poly(maleic acid amide-co-vinyl acetate) on Asphaltene Precipitation in Heavy Oil
    2018
    Co-Authors: Run Zou, Decheng Gai, Pascal Theil, Linda Pickenbach, Martien Cohen A Stuart, Xuhong Guo
    Abstract:

    Asphaltene Precipitation often brings difficulties to the recovery and transportation of heavy crude oil. Poly­(maleic acid amide-co-vinyl acetate) copolymers with various aromatic (phenyl, naphthyl, and benzimidazole) pendants and/or aliphatic (octyl, tetradecyl, and octadecyl) grafts were synthesized and found to be capable of dispersing asphaltenes effectively. To study the influence of aromatic and aliphatic pendants in copolymers on asphaltene Precipitation behaviors, the initial Precipitation Point, turbidity, and size of asphaltene precipitates from model heavy oils in the presence and absence of copolymers were determined by UV–vis spectroscopy, turbidity meter, and dynamic light scattering, respectively. The effect of copolymers on the viscosity of Tahe heavy oil with high asphaltene content was investigated by the rheological approach. The results revealed that the copolymers with both aromatic and aliphatic pendants dispersed asphaltene, reduced its precipitates, and thus improved the flowability of Tahe heavy oil more effectively than those with only aromatic or aliphatic graft. The combination of “π–π delocalized conjugation attraction” from aromatic pendants and “steric blocking” from aliphatic grafts should be the reason