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Yuri P. Belov - One of the best experts on this subject based on the ideXlab platform.

  • Sol–gel multicapillary columns for gas–solid Chromatography
    Journal of Chromatography A, 2005
    Co-Authors: Vladimir N. Sidelnikov, Yuri V. Patrushev, Yuri P. Belov
    Abstract:

    Abstract In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas–solid Chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol–gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas–solid Chromatography. Nine-component mixtures of C1–C4 hydrocarbons are separated within 8–12 s. The efficiency of 25–30 cm long alumina sol–gel MCCs consisting of approximately 1400 capillaries of 40 μm diameter is up to 2500–3000 theoretical plates.

  • Sol-gel multicapillary columns for Gas-Solid Chromatography.
    Journal of chromatography. A, 2005
    Co-Authors: Vladimir N. Sidelnikov, Yuri V. Patrushev, Yuri P. Belov
    Abstract:

    In this work, we report the method for the preparation of multicapillary columns (MCCs) for Gas-Solid Chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol-gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by Gas-Solid Chromatography. Nine-component mixtures of C1-C4 hydrocarbons are separated within 8-12 s. The efficiency of 25-30 cm long alumina sol-gel MCCs consisting of approximately 1400 capillaries of 40 microm diameter is up to 2500-3000 theoretical plates.

Vladimir N. Sidelnikov - One of the best experts on this subject based on the ideXlab platform.

  • Sol–gel multicapillary columns for gas–solid Chromatography
    Journal of Chromatography A, 2005
    Co-Authors: Vladimir N. Sidelnikov, Yuri V. Patrushev, Yuri P. Belov
    Abstract:

    Abstract In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas–solid Chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol–gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas–solid Chromatography. Nine-component mixtures of C1–C4 hydrocarbons are separated within 8–12 s. The efficiency of 25–30 cm long alumina sol–gel MCCs consisting of approximately 1400 capillaries of 40 μm diameter is up to 2500–3000 theoretical plates.

  • Sol-gel multicapillary columns for Gas-Solid Chromatography.
    Journal of chromatography. A, 2005
    Co-Authors: Vladimir N. Sidelnikov, Yuri V. Patrushev, Yuri P. Belov
    Abstract:

    In this work, we report the method for the preparation of multicapillary columns (MCCs) for Gas-Solid Chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol-gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by Gas-Solid Chromatography. Nine-component mixtures of C1-C4 hydrocarbons are separated within 8-12 s. The efficiency of 25-30 cm long alumina sol-gel MCCs consisting of approximately 1400 capillaries of 40 microm diameter is up to 2500-3000 theoretical plates.

Yuri V. Patrushev - One of the best experts on this subject based on the ideXlab platform.

  • Sol–gel multicapillary columns for gas–solid Chromatography
    Journal of Chromatography A, 2005
    Co-Authors: Vladimir N. Sidelnikov, Yuri V. Patrushev, Yuri P. Belov
    Abstract:

    Abstract In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas–solid Chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol–gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas–solid Chromatography. Nine-component mixtures of C1–C4 hydrocarbons are separated within 8–12 s. The efficiency of 25–30 cm long alumina sol–gel MCCs consisting of approximately 1400 capillaries of 40 μm diameter is up to 2500–3000 theoretical plates.

  • Sol-gel multicapillary columns for Gas-Solid Chromatography.
    Journal of chromatography. A, 2005
    Co-Authors: Vladimir N. Sidelnikov, Yuri V. Patrushev, Yuri P. Belov
    Abstract:

    In this work, we report the method for the preparation of multicapillary columns (MCCs) for Gas-Solid Chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol-gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by Gas-Solid Chromatography. Nine-component mixtures of C1-C4 hydrocarbons are separated within 8-12 s. The efficiency of 25-30 cm long alumina sol-gel MCCs consisting of approximately 1400 capillaries of 40 microm diameter is up to 2500-3000 theoretical plates.

Thomas R. Rybolt - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Gas-Solid Chromatography and MM2 force field molecular binding energies for greenhouse gases on a carbonaceous surface.
    Journal of colloid and interface science, 2009
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Kevin T. Bivona, Casey M. O’dell
    Abstract:

    Abstract Gas–solid Chromatography was used to determine B2s (gas–solid virial coefficient) values for eight molecular adsorbates interacting with a carbon powder (Carbopack B, Supelco). B2s values were determined by multiple size variant injections within the temperature range of 313–553 K. The molecular adsorbates included: carbon dioxide (CO2); tetrafluoromethane (CF4); hexafluoroethane (C2F6); 1,1-difluoroethane (C2H4F2); 1-chloro-1,1-difluoroethane (C2H3ClF2); dichlorodifluoromethane (CCl2F2); trichlorofluoromethane (CCl3F); and 1,1,1-trichloroethane (C2H3Cl3). Two of these molecules are of special interest because they are “super greenhouse gases”. The global warming potential, GWP, for CF4 is 6500 and for C2F6 is 9200 relative to the reference value of 1 for CO2. The GWP index considers both radiative blocking and molecular lifetime. For these and other industrial greenhouse gases, adsorptive trapping on a carbonaceous solid, which depends on molecule–surface binding energy, could avoid atmospheric release. The temperature variations of the gas–solid virial coefficients in conjunction with van’t Hoff plots were used to find the experimental adsorption energy or binding energy values (E*) for each adsorbate. A molecular mechanics based, rough-surface model was used to calculate the molecule–surface binding energy (Ecal*) using augmented MM2 parameters. The surface model consisted of parallel graphene layers with two separated nanostructures each containing 17 benzene rings arranged in linear strips. The separation of the parallel nanostructures had been optimized in a prior study to appropriately represent molecule–surface interactions for Carbopack B. Linear regressions of E* versus Ecal* for the current data set of eight molecules and the same surface model gave E* = 0.926Ecal* and r2=0.956. A combined set of the current and prior Carbopack B adsorbates studied (linear alkanes, branched alkanes, cyclic alkanes, ethers, and halogenated hydrocarbons) gave a data set with 33 molecules and a regression of E* = 0.991Ecal* and r2=0.968. These results indicated a good correlation between the experimental and the MM2 computed molecule–surface binding energies.

  • Binding energies for alkane molecules on a carbon surface from Gas-Solid Chromatography and molecular mechanics.
    Journal of colloid and interface science, 2008
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Christina E. Wells, Craig M. Goodwin, Jennifer L. Blakely, James D. Turner
    Abstract:

    Gas-Solid Chromatography was used to determine B(2s) (Gas-Solid virial coefficient) values for 12 alkanes (10 branched and 2 cyclic) interacting with a carbon powder (Carbopack B, Supelco). B(2s) values were determined by multiple size variant injections within the temperature range of 393 to 623 K with each alkane measured at 5 or 6 different temperatures. The temperature variations of the Gas-Solid virial coefficients were used to find the experimental adsorption energy or binding energy values (E( *)) for each alkane. A molecular mechanics based, rough-surface model was used to calculate the molecule-surface binding energy (E(cal)( *)) using augmented MM2 parameters. The surface model consisted of three parallel graphene layers with each layer containing 127 interconnected benzene rings and two separated nanostructures each containing 17 benzene rings arranged in a linear strip. As the parallel nanostructures are moved closer together, the surface roughness increases and molecule-surface interactions are enhanced. A comparison of the experimental and calculated binding energies showed excellent agreement with an average difference of 3.8%. Linear regressions of E( *) versus E(cal)( *) for the current data set and a combined current and prior alkane data set both gave excellent correlations. For the combined data set with 18 linear, branched and cyclic alkanes; a linear regression of E( *)=0.9848E(cal)( *) and r(2)=0.976 was obtained. The results indicate that alkane-surface binding energies may be calculated from MM2 parameters for some Gas-Solid systems.

  • Adsorption energies for a nanoporous carbon from Gas-Solid Chromatography and molecular mechanics.
    Journal of colloid and interface science, 2005
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Katherine A. Ziegler, Jennifer L. Boyd, Mark E. Ridgeway
    Abstract:

    Abstract Gas–solid Chromatography was used to obtain second gas–solid virial coefficients, B 2 s , in the temperature range 342–613 K for methane, ethane, propane, butane, 2-methylpropane, chloromethane, chlorodifluoromethane, dichloromethane, and dichlorodifluoromethane. The adsorbent used was Carbosieve S-III (Supelco), a carbon powder with fairly uniform, predominately 0.55 nm slit width pores and a N 2 BET surface area of 995 m 2 /g. The temperature dependence of B 2 s was used to determine experimental values of the gas–solid interaction energy, E ∗ , for each of these molecular adsorbates. MM2 and MM3 molecular mechanics calculations were used to determine the gas–solid interaction energy, E cal ∗ , for each of the molecules on various flat and nanoporous model surfaces. The flat model consisted of three parallel graphene layers with each graphene layer containing 127 interconnected benzene rings. The nanoporous model consisted of two sets of three parallel graphene layers adjacent to one another but separated to represent the pore diameter. A variety of calculated adsorption energies, E cal ∗ , were compared and correlated to the experimental E ∗ values. It was determined that simple molecular mechanics could be used to calculate an attraction energy parameter between an adsorbed molecule and the carbon surface. The best correlation between the E cal ∗ and E ∗ values was provided by a 0.50 nm nanoporous model using MM2 parameters.

  • Henry's law Gas-Solid Chromatography and correlations of virial coefficients for hydrocarbons, chlorofluorocarbons, ethers, and sulfur hexafluoride adsorbed onto carbon
    Journal of Colloid and Interface Science, 1995
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Matthew T. Epperson, Holly W. Weaver, Sharon E. Clare, Benjamin M. Manning, Jeffrey T. Mcclung
    Abstract:

    Gas-Solid Chromatography was used to determine the Henry's law second Gas-Solid virial coefficients within the temperature range of 314-615 K for ethane, propane, butane, isobutane, pentane, hexane, heptane, chloromethane, dichloromethane, trichloromethane, tetrachloromethane, trichlorofluoromethane (Freon 11), chlorodifluoromethane (Freon 22), dichlorodifluoromethane (Freon 12), methyl ether, ethyl ether, and sulfur hexafluoride with Carbopack B, a microporous carbon adsorbent. The temperature dependence of the second Gas-Solid virial coefficients of these adsorbates was used in conjunction with analyses based on a graphical method, a single-surface numeric integration method, a single-surface analytic expression method, and a two-surface analytic expression method to determine the Gas-Solid interaction energies and other parameters. The interaction energies were correlated with a ratio of the critical temperature divided by the square root of the critical pressure. The four methods were compared in their abilities to successfully calculate second Gas-Solid virial coefficient values.

  • Gas—solid Chromatography and virial analysis of chlorofluorocarbon adsorption on a microporous carbon
    Journal of Colloid and Interface Science, 1992
    Co-Authors: Thomas R. Rybolt, Xike Zhang, Michael D Wall, Howard E. Thomas, Lauren E Mullinax, J.robin Lee
    Abstract:

    Abstract Gas-Solid Chromatography was used to determine the second Gas-Solid virial coefficients in the temperature range 373–512 K for ethane, propane, chloromethane, dichloromethane, fluoromethane, chlorodifluoromethane (Freon 22), and dichlorodifluoromethane (Freon 12), with Super Sorb, a microporous carbon adsorbent. The temperature dependence of the second Gas-Solid virial coefficients of these adsorbates was used in conjunction with a Lennard-Jones and Devonshire cell model to determine the effective structural parameters of cavity radius and number of cavities per gram of adsorbent, as well as gas-cavity interaction energies. The interaction energies were correlated with adsorbate boiling points and energetic additivity rules based on molecular structure including the number of atoms of different types in the molecule and the dipole moment of the molecule.

Howard E. Thomas - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Gas-Solid Chromatography and MM2 force field molecular binding energies for greenhouse gases on a carbonaceous surface.
    Journal of colloid and interface science, 2009
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Kevin T. Bivona, Casey M. O’dell
    Abstract:

    Abstract Gas–solid Chromatography was used to determine B2s (gas–solid virial coefficient) values for eight molecular adsorbates interacting with a carbon powder (Carbopack B, Supelco). B2s values were determined by multiple size variant injections within the temperature range of 313–553 K. The molecular adsorbates included: carbon dioxide (CO2); tetrafluoromethane (CF4); hexafluoroethane (C2F6); 1,1-difluoroethane (C2H4F2); 1-chloro-1,1-difluoroethane (C2H3ClF2); dichlorodifluoromethane (CCl2F2); trichlorofluoromethane (CCl3F); and 1,1,1-trichloroethane (C2H3Cl3). Two of these molecules are of special interest because they are “super greenhouse gases”. The global warming potential, GWP, for CF4 is 6500 and for C2F6 is 9200 relative to the reference value of 1 for CO2. The GWP index considers both radiative blocking and molecular lifetime. For these and other industrial greenhouse gases, adsorptive trapping on a carbonaceous solid, which depends on molecule–surface binding energy, could avoid atmospheric release. The temperature variations of the gas–solid virial coefficients in conjunction with van’t Hoff plots were used to find the experimental adsorption energy or binding energy values (E*) for each adsorbate. A molecular mechanics based, rough-surface model was used to calculate the molecule–surface binding energy (Ecal*) using augmented MM2 parameters. The surface model consisted of parallel graphene layers with two separated nanostructures each containing 17 benzene rings arranged in linear strips. The separation of the parallel nanostructures had been optimized in a prior study to appropriately represent molecule–surface interactions for Carbopack B. Linear regressions of E* versus Ecal* for the current data set of eight molecules and the same surface model gave E* = 0.926Ecal* and r2=0.956. A combined set of the current and prior Carbopack B adsorbates studied (linear alkanes, branched alkanes, cyclic alkanes, ethers, and halogenated hydrocarbons) gave a data set with 33 molecules and a regression of E* = 0.991Ecal* and r2=0.968. These results indicated a good correlation between the experimental and the MM2 computed molecule–surface binding energies.

  • Binding energies for alkane molecules on a carbon surface from Gas-Solid Chromatography and molecular mechanics.
    Journal of colloid and interface science, 2008
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Christina E. Wells, Craig M. Goodwin, Jennifer L. Blakely, James D. Turner
    Abstract:

    Gas-Solid Chromatography was used to determine B(2s) (Gas-Solid virial coefficient) values for 12 alkanes (10 branched and 2 cyclic) interacting with a carbon powder (Carbopack B, Supelco). B(2s) values were determined by multiple size variant injections within the temperature range of 393 to 623 K with each alkane measured at 5 or 6 different temperatures. The temperature variations of the Gas-Solid virial coefficients were used to find the experimental adsorption energy or binding energy values (E( *)) for each alkane. A molecular mechanics based, rough-surface model was used to calculate the molecule-surface binding energy (E(cal)( *)) using augmented MM2 parameters. The surface model consisted of three parallel graphene layers with each layer containing 127 interconnected benzene rings and two separated nanostructures each containing 17 benzene rings arranged in a linear strip. As the parallel nanostructures are moved closer together, the surface roughness increases and molecule-surface interactions are enhanced. A comparison of the experimental and calculated binding energies showed excellent agreement with an average difference of 3.8%. Linear regressions of E( *) versus E(cal)( *) for the current data set and a combined current and prior alkane data set both gave excellent correlations. For the combined data set with 18 linear, branched and cyclic alkanes; a linear regression of E( *)=0.9848E(cal)( *) and r(2)=0.976 was obtained. The results indicate that alkane-surface binding energies may be calculated from MM2 parameters for some Gas-Solid systems.

  • Adsorption energies for a nanoporous carbon from Gas-Solid Chromatography and molecular mechanics.
    Journal of colloid and interface science, 2005
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Katherine A. Ziegler, Jennifer L. Boyd, Mark E. Ridgeway
    Abstract:

    Abstract Gas–solid Chromatography was used to obtain second gas–solid virial coefficients, B 2 s , in the temperature range 342–613 K for methane, ethane, propane, butane, 2-methylpropane, chloromethane, chlorodifluoromethane, dichloromethane, and dichlorodifluoromethane. The adsorbent used was Carbosieve S-III (Supelco), a carbon powder with fairly uniform, predominately 0.55 nm slit width pores and a N 2 BET surface area of 995 m 2 /g. The temperature dependence of B 2 s was used to determine experimental values of the gas–solid interaction energy, E ∗ , for each of these molecular adsorbates. MM2 and MM3 molecular mechanics calculations were used to determine the gas–solid interaction energy, E cal ∗ , for each of the molecules on various flat and nanoporous model surfaces. The flat model consisted of three parallel graphene layers with each graphene layer containing 127 interconnected benzene rings. The nanoporous model consisted of two sets of three parallel graphene layers adjacent to one another but separated to represent the pore diameter. A variety of calculated adsorption energies, E cal ∗ , were compared and correlated to the experimental E ∗ values. It was determined that simple molecular mechanics could be used to calculate an attraction energy parameter between an adsorbed molecule and the carbon surface. The best correlation between the E cal ∗ and E ∗ values was provided by a 0.50 nm nanoporous model using MM2 parameters.

  • Henry's law Gas-Solid Chromatography and correlations of virial coefficients for hydrocarbons, chlorofluorocarbons, ethers, and sulfur hexafluoride adsorbed onto carbon
    Journal of Colloid and Interface Science, 1995
    Co-Authors: Thomas R. Rybolt, Howard E. Thomas, Matthew T. Epperson, Holly W. Weaver, Sharon E. Clare, Benjamin M. Manning, Jeffrey T. Mcclung
    Abstract:

    Gas-Solid Chromatography was used to determine the Henry's law second Gas-Solid virial coefficients within the temperature range of 314-615 K for ethane, propane, butane, isobutane, pentane, hexane, heptane, chloromethane, dichloromethane, trichloromethane, tetrachloromethane, trichlorofluoromethane (Freon 11), chlorodifluoromethane (Freon 22), dichlorodifluoromethane (Freon 12), methyl ether, ethyl ether, and sulfur hexafluoride with Carbopack B, a microporous carbon adsorbent. The temperature dependence of the second Gas-Solid virial coefficients of these adsorbates was used in conjunction with analyses based on a graphical method, a single-surface numeric integration method, a single-surface analytic expression method, and a two-surface analytic expression method to determine the Gas-Solid interaction energies and other parameters. The interaction energies were correlated with a ratio of the critical temperature divided by the square root of the critical pressure. The four methods were compared in their abilities to successfully calculate second Gas-Solid virial coefficient values.

  • Gas—solid Chromatography and virial analysis of chlorofluorocarbon adsorption on a microporous carbon
    Journal of Colloid and Interface Science, 1992
    Co-Authors: Thomas R. Rybolt, Xike Zhang, Michael D Wall, Howard E. Thomas, Lauren E Mullinax, J.robin Lee
    Abstract:

    Abstract Gas-Solid Chromatography was used to determine the second Gas-Solid virial coefficients in the temperature range 373–512 K for ethane, propane, chloromethane, dichloromethane, fluoromethane, chlorodifluoromethane (Freon 22), and dichlorodifluoromethane (Freon 12), with Super Sorb, a microporous carbon adsorbent. The temperature dependence of the second Gas-Solid virial coefficients of these adsorbates was used in conjunction with a Lennard-Jones and Devonshire cell model to determine the effective structural parameters of cavity radius and number of cavities per gram of adsorbent, as well as gas-cavity interaction energies. The interaction energies were correlated with adsorbate boiling points and energetic additivity rules based on molecular structure including the number of atoms of different types in the molecule and the dipole moment of the molecule.