Waheed Afzal - Academia.edu (original) (raw)

Papers by Waheed Afzal

Research paper thumbnail of Solubilities of some organic solutes in 1-ethyl-3-methylimidazolium acetate. Chromatographic measurements and predictions from COSMO-RS

The Journal of Chemical Thermodynamics, Apr 1, 2012

ABSTRACT Infinite-dilution activity coefficients and Henry’s constants for several organic solute... more ABSTRACT Infinite-dilution activity coefficients and Henry’s constants for several organic solutes in 1-ethyl-3-methylimidazolium acetate [EMIM][Ac] were measured from T = 313 K to T = 413 K using two types of gas–liquid chromatography columns: packed columns and an open tubular wall-coated (OTWC) column. The organic solutes include n-hexane, 1-hexene, cyclohexane, heptane, benzene, toluene, ethyl acetate, tetrahydrofuran, 1,4-dioxane, acetonitrile, nitromethane, 1,2-methoxyethane, 1-propanol, 2-propanol, t-butanol and t-amyl alcohol. Results using packed columns are in good agreement with those using the OTWC column. However, there is a useful advantage associated with an OTWC column: for solutes such as alcohols, that have strong interactions with the stationary phase, measurements are faster due to their shorter retention time compared to those in packed columns.

Research paper thumbnail of Unusual trend of viscosities and densities for four ionic liquids containing a tetraalkyl phosphonium cation and the anion bis(2,4,4-trimethylpentyl) phosphinate

The Journal of Chemical Thermodynamics, Mar 1, 2014

Research paper thumbnail of Nitric-acid hydrolysis of Miscanthus giganteus to sugars fermented to bioethanol

Biotechnology and Bioprocess Engineering, Apr 1, 2015

Research paper thumbnail of Solubilities of small hydrocarbons, viscosities of diluted tetraalkylphosphonium bis(2,4,4-trimethylpentyl) phosphinates

Aiche Journal, Apr 18, 2014

Research paper thumbnail of Effect of Water on the Densities and Viscosities of Some Ionic Liquids Containing a Phosphonium Cation

Zeitschrift für Physikalische Chemie, Jan 28, 2013

A small amount of water can significantly decrease the viscosity of an ionic liquid. From 25–80 º... more A small amount of water can significantly decrease the viscosity of an ionic liquid. From 25–80 ºC, densities and viscosities were measured for dilute solutions of water in six ionic liquids: trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate, trihexyltetradecylphosphonium dicyanamide, tributyltetradecylphosphonium dodecylbenzenesulfonate, 1-ethyl,3-methylimidazolium bis(triflouromethylsulfonyl)imide, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, and triisobutylmethylphosphonium tosylate. At 25 ºC, when the water content is about 1 wt. %, the viscosity of a phosphonium-based ionic liquid is reduced by nearly one order of magnitude.

Research paper thumbnail of Development of a Bespoke Enhanced Oil Recovery (EOR) Technology: A Future for Angolan Oilfield Production

Research paper thumbnail of Hydrocracking of surgical face masks over Y Zeolites: Catalyst development, process design and life cycle assessment

Research paper thumbnail of Pretreatment of <em>Miscanthus giganteus</em> with Lime and Oxidants for Biofuels

Energy & Fuels, Feb 10, 2015

Research paper thumbnail of Henry’s constants and activity coefficients of some organic solutes in 1-butyl,3-methylimidazolium hydrogen sulfate and in 1-methyl,3-trimethylsilylmethylimidazolium chloride

The Journal of Chemical Thermodynamics, Feb 1, 2013

ABSTRACT Using a customized capillary gas–liquid chromatography column, Henry’s constants and act... more ABSTRACT Using a customized capillary gas–liquid chromatography column, Henry’s constants and activity coefficients at infinite dilution are reported for benzene, toluene, ethyl acetate, 1,4-dioxane, 1,2-dimethoxyethane, acetonitrile, nitromethane, tetrahydrofuran, chloroform, methanol, ethanol, and 1-propanol in ionic liquids 1-butyl,3-methylimidazolium hydrogen sulfate [BMIM][HSO4] and 1-methyl,3-trimethylsilylmethylimidazolium [SiMIM][Cl] chloride from 313 to 413 K. These acidic ionic liquids may provide suitable media for acid-catalyzed chemical reactions.

Research paper thumbnail of Solubility Parameters for Nine Ionic Liquids

Industrial & Engineering Chemistry Research, Jul 13, 2012

ABSTRACT Solubility parameters are useful for estimating solubilities of solutes in ionic liquids... more ABSTRACT Solubility parameters are useful for estimating solubilities of solutes in ionic liquids when no solubility data are available. Solubility parameters are reported for nine ionic liquids; they were obtained from solubility data for a variety of solutes. The ionic liquids are 1-butyl,3-methylimidazolium hydrogen sulfate, 1-ethyl,3-methylimidazolium acetate, 1-methyl,3-trimethylsylilimidazolium chloride, 4-methyl,n-butylpyridinium tetrafluoroborate, ethylammonium nitrate, 1-ethyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-ethyl,3-methylimidazolium ethylsulfate.

Research paper thumbnail of Ecological study of a mineral carbon capture and conversion process

Research paper thumbnail of Microwave-assisted regeneration of solid adsorbents for CO2 capture in post-combustion processes

Research paper thumbnail of Solubilities, Densities and Viscosities of Two Low-Density Ionic Liquids Containing Small Hydrocarbons

Research paper thumbnail of Phase equilibria of glycol-natural gas systems (PhD Dissertation)

Research paper thumbnail of Separation of Small Paraffin-Olefin Mixtures With An Ionic Liquid: Thermodynamic Study Using COSMO-RS

Research paper thumbnail of Saccharification of Miscanthus $ Giganteus With Dilute Nitric Acid

Research paper thumbnail of Mechanical Properties of Eichhornia Crassipes Fiber as Lost Circulation Material for Oil and Gas Drilling Application

Advances in engineering research, 2021

Research paper thumbnail of Viscosities and Densities of Phosphonium-Based Ionic Liquids Mixed with Dodecane

Zeitschrift für Physikalische Chemie, Jul 8, 2014

Research paper thumbnail of A systematic analysis of the dynamics of microwave- and conventionally-assisted swing adsorption on zeolite 13X and an activated carbon under post-combustion carbon capture conditions

Journal of environmental chemical engineering, Dec 1, 2021

Research paper thumbnail of High Solubilities of Small Hydrocarbons in Trihexyl Tetradecylphosphonium Bis(2,4,4-trimethylpentyl) Phosphinate

Journal of Physical Chemistry B, Aug 30, 2013

Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in t... more Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P(14)666][TMPP] from 313 to 353 K up to 6.7 MPa. A literature review on solubilities of small hydrocarbons in ionic liquids shows that solubilities in [P(14)666][TMPP] are appreciably larger than those in other ionic liquids. Contrary to solubilities in ionic liquids studied earlier, solubilities of paraffins (ethane and propane) in [P(14)666][TMPP] are larger than those of the corresponding olefins (ethylene and propylene). Because, at fixed temperature, the vapor pressure of an olefin is larger than that of the corresponding paraffin, the relative volatility of the olefin exceeds that of the corresponding paraffin, contrary to the relative volatility observed in conventional extractive distillation with polar solvents where the volatility of the paraffin exceeds that of the corresponding olefin.

Research paper thumbnail of Solubilities of some organic solutes in 1-ethyl-3-methylimidazolium acetate. Chromatographic measurements and predictions from COSMO-RS

The Journal of Chemical Thermodynamics, Apr 1, 2012

ABSTRACT Infinite-dilution activity coefficients and Henry’s constants for several organic solute... more ABSTRACT Infinite-dilution activity coefficients and Henry’s constants for several organic solutes in 1-ethyl-3-methylimidazolium acetate [EMIM][Ac] were measured from T = 313 K to T = 413 K using two types of gas–liquid chromatography columns: packed columns and an open tubular wall-coated (OTWC) column. The organic solutes include n-hexane, 1-hexene, cyclohexane, heptane, benzene, toluene, ethyl acetate, tetrahydrofuran, 1,4-dioxane, acetonitrile, nitromethane, 1,2-methoxyethane, 1-propanol, 2-propanol, t-butanol and t-amyl alcohol. Results using packed columns are in good agreement with those using the OTWC column. However, there is a useful advantage associated with an OTWC column: for solutes such as alcohols, that have strong interactions with the stationary phase, measurements are faster due to their shorter retention time compared to those in packed columns.

Research paper thumbnail of Unusual trend of viscosities and densities for four ionic liquids containing a tetraalkyl phosphonium cation and the anion bis(2,4,4-trimethylpentyl) phosphinate

The Journal of Chemical Thermodynamics, Mar 1, 2014

Research paper thumbnail of Nitric-acid hydrolysis of Miscanthus giganteus to sugars fermented to bioethanol

Biotechnology and Bioprocess Engineering, Apr 1, 2015

Research paper thumbnail of Solubilities of small hydrocarbons, viscosities of diluted tetraalkylphosphonium bis(2,4,4-trimethylpentyl) phosphinates

Aiche Journal, Apr 18, 2014

Research paper thumbnail of Effect of Water on the Densities and Viscosities of Some Ionic Liquids Containing a Phosphonium Cation

Zeitschrift für Physikalische Chemie, Jan 28, 2013

A small amount of water can significantly decrease the viscosity of an ionic liquid. From 25–80 º... more A small amount of water can significantly decrease the viscosity of an ionic liquid. From 25–80 ºC, densities and viscosities were measured for dilute solutions of water in six ionic liquids: trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate, trihexyltetradecylphosphonium dicyanamide, tributyltetradecylphosphonium dodecylbenzenesulfonate, 1-ethyl,3-methylimidazolium bis(triflouromethylsulfonyl)imide, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, and triisobutylmethylphosphonium tosylate. At 25 ºC, when the water content is about 1 wt. %, the viscosity of a phosphonium-based ionic liquid is reduced by nearly one order of magnitude.

Research paper thumbnail of Development of a Bespoke Enhanced Oil Recovery (EOR) Technology: A Future for Angolan Oilfield Production

Research paper thumbnail of Hydrocracking of surgical face masks over Y Zeolites: Catalyst development, process design and life cycle assessment

Research paper thumbnail of Pretreatment of <em>Miscanthus giganteus</em> with Lime and Oxidants for Biofuels

Energy & Fuels, Feb 10, 2015

Research paper thumbnail of Henry’s constants and activity coefficients of some organic solutes in 1-butyl,3-methylimidazolium hydrogen sulfate and in 1-methyl,3-trimethylsilylmethylimidazolium chloride

The Journal of Chemical Thermodynamics, Feb 1, 2013

ABSTRACT Using a customized capillary gas–liquid chromatography column, Henry’s constants and act... more ABSTRACT Using a customized capillary gas–liquid chromatography column, Henry’s constants and activity coefficients at infinite dilution are reported for benzene, toluene, ethyl acetate, 1,4-dioxane, 1,2-dimethoxyethane, acetonitrile, nitromethane, tetrahydrofuran, chloroform, methanol, ethanol, and 1-propanol in ionic liquids 1-butyl,3-methylimidazolium hydrogen sulfate [BMIM][HSO4] and 1-methyl,3-trimethylsilylmethylimidazolium [SiMIM][Cl] chloride from 313 to 413 K. These acidic ionic liquids may provide suitable media for acid-catalyzed chemical reactions.

Research paper thumbnail of Solubility Parameters for Nine Ionic Liquids

Industrial & Engineering Chemistry Research, Jul 13, 2012

ABSTRACT Solubility parameters are useful for estimating solubilities of solutes in ionic liquids... more ABSTRACT Solubility parameters are useful for estimating solubilities of solutes in ionic liquids when no solubility data are available. Solubility parameters are reported for nine ionic liquids; they were obtained from solubility data for a variety of solutes. The ionic liquids are 1-butyl,3-methylimidazolium hydrogen sulfate, 1-ethyl,3-methylimidazolium acetate, 1-methyl,3-trimethylsylilimidazolium chloride, 4-methyl,n-butylpyridinium tetrafluoroborate, ethylammonium nitrate, 1-ethyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-ethyl,3-methylimidazolium ethylsulfate.

Research paper thumbnail of Ecological study of a mineral carbon capture and conversion process

Research paper thumbnail of Microwave-assisted regeneration of solid adsorbents for CO2 capture in post-combustion processes

Research paper thumbnail of Solubilities, Densities and Viscosities of Two Low-Density Ionic Liquids Containing Small Hydrocarbons

Research paper thumbnail of Phase equilibria of glycol-natural gas systems (PhD Dissertation)

Research paper thumbnail of Separation of Small Paraffin-Olefin Mixtures With An Ionic Liquid: Thermodynamic Study Using COSMO-RS

Research paper thumbnail of Saccharification of Miscanthus $ Giganteus With Dilute Nitric Acid

Research paper thumbnail of Mechanical Properties of Eichhornia Crassipes Fiber as Lost Circulation Material for Oil and Gas Drilling Application

Advances in engineering research, 2021

Research paper thumbnail of Viscosities and Densities of Phosphonium-Based Ionic Liquids Mixed with Dodecane

Zeitschrift für Physikalische Chemie, Jul 8, 2014

Research paper thumbnail of A systematic analysis of the dynamics of microwave- and conventionally-assisted swing adsorption on zeolite 13X and an activated carbon under post-combustion carbon capture conditions

Journal of environmental chemical engineering, Dec 1, 2021

Research paper thumbnail of High Solubilities of Small Hydrocarbons in Trihexyl Tetradecylphosphonium Bis(2,4,4-trimethylpentyl) Phosphinate

Journal of Physical Chemistry B, Aug 30, 2013

Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in t... more Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P(14)666][TMPP] from 313 to 353 K up to 6.7 MPa. A literature review on solubilities of small hydrocarbons in ionic liquids shows that solubilities in [P(14)666][TMPP] are appreciably larger than those in other ionic liquids. Contrary to solubilities in ionic liquids studied earlier, solubilities of paraffins (ethane and propane) in [P(14)666][TMPP] are larger than those of the corresponding olefins (ethylene and propylene). Because, at fixed temperature, the vapor pressure of an olefin is larger than that of the corresponding paraffin, the relative volatility of the olefin exceeds that of the corresponding paraffin, contrary to the relative volatility observed in conventional extractive distillation with polar solvents where the volatility of the paraffin exceeds that of the corresponding olefin.