Firdosa Nabi - Academia.edu (original) (raw)

Papers by Firdosa Nabi

The issue of the effects of corrosion on structural integrity of metal surfaces has been a questi... more The issue of the effects of corrosion on structural integrity of metal surfaces has been a question of concern for some time. The uses of chemical corrosion inhibitors are common in production and processing operations. Nevertheless, the challenge is to develop a new class of corrosion inhibitors to protect the materials, which are environment friendly under various conditions. Surfactants as corrosion inhibitors are environmentally acceptable and are very economical and easily available. The aim of this review article is to delineate the ability of surfactants to inhibit the corrosion on different metal surfaces. Various potential application and properties of different types surfactants have also been discussed. Various parameters like, effect of surfactant concentration, temperature and the mechanism of corrosion inhibition and mode of adsorption are also discussed in this review article.

Indian Journal of Pure & Applied Physics, 2008

Experimental viscosities, η of pure benzene, 1,2-dichloroethane (DCE), 1,1,2,2-tetrachloroethane ... more Experimental viscosities, η of pure benzene, 1,2-dichloroethane (DCE), 1,1,2,2-tetrachloroethane (TCE) and those of their binary mixtures, having benzene as a common component, have been measured over the whole composition range at 298.15, 303.15, 308.15, 313.15 and 318.15 K. The experimental η data were then fitted to standard polynomial against composition. Using η values, the deviations in viscosities, Δη, excess Gibbs free energies of activation of viscous flow, ΔG *E , entropies, ΔS* and enthalpies, ΔH* of activation of viscous flow have been calculated. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. Further, the excess molar volumes, V E were calculated using data for both the binary mixtures. Moreover, Grunberg-Nissan and Isdale's group contribution methods have been used to calculate the viscosities of mixtures and the results were discussed in terms of average percentage deviations (APD) in e...

Zeitschrift für Physikalische Chemie

The densities, ρ, viscosities, η and specific conductivities κ, of (0.0002, 0.0004, 0.0006 and 0.... more The densities, ρ, viscosities, η and specific conductivities κ, of (0.0002, 0.0004, 0.0006 and 0.0008 m) CTAB in 0.1 m aqueous valine, leucine and isoleucine were measured at different temperatures. The measured data were used to calculate various useful thermodynamic parameters. A complete characterization of any mixture can be performed by means of these thermodynamic properties. The apparent molar volume, ϕv, partial molar volume, phiv0\phi _v^0phiv0 and partial molar isobaric expansibilities, phiE0,\phi _E^0,phiE0, were calculated using density data. The viscosity data were analyzed using Jones–Dole equation to obtain viscosity coefficients, A- and B-, free energy of activation per mole of solvent, Δμ1°∗, and solute, Δμ2°∗, enthalpy, ΔH∗ and entropy, ΔS∗ of activation of viscous flow. Measuring the changes in these properties has been found to be an excellent qualitative and quantitative way to obtain information regarding the molecular structure and intermolecular interactions occurring in these...

International Journal of Thermophysics

The interactions of glycylglycine (di-peptide of glycine) also known as 2-[(2-aminoacetyl)amino] ... more The interactions of glycylglycine (di-peptide of glycine) also known as 2-[(2-aminoacetyl)amino] acetic acid with cationic surfactants cetylpyridinium chloride (CPC) and cetylpyridinium bromide (CPB) as a function of temperature in aqueous medium has been studied by well-know permutation of volumetric, ultrasonic and conductometric techniques. These measurements have been used to evaluate some useful thermodynamic parameters viz. apparent molar volumes, phiv\phi_{v}phivϕv, partial molar volumes, phivo\phi_{v}^{o}phivoϕvo, transfer volumes, phitextv0(tr)\phi_{\text{v}}^{0} (tr)phitextv0(tr)ϕv0(tr), partial molar expansibility, phiE0\phi_{E}^{0}phiE0ϕE0, hydration number, nH, apparent molal compressibility, phiK\phi_{K}phiKϕK, limiting partial molal adiabatic compressibility, phiK0\phi_{K}^{0}phiK0ϕK0. The specific conductivity (κ) was used to calculate the critical micellar concentration (cmc) and other physicochemical parameters of micellization of CPC/CPB with glycylglycine. The critical micelle concentration, cmc and limiting molar conductivity, varLambdamo\varLambda_{m}^{o}varLambdamoΛmo of the two surfactant systems were determined by using the conductivity data at 298.15 K, 303.15 K, 308.15 K and 313.15 K. The acquired data have been discussed as per various interactions taking place in the ternary system of CPC/CPB, glycylglycine and water.

Acta Physico-Chimica Sinica

： Thedensities(籽),ultrasonicspeeds(v),andrefractiveindices(n)ofbinarymixturesofstyrene(STY) with ... more ： Thedensities(籽),ultrasonicspeeds(v),andrefractiveindices(n)ofbinarymixturesofstyrene(STY) with m鄄, o鄄,or p鄄xylene,includingthoseoftheirpureliquids,weremeasuredovertheentirecompositionrangeatthe temperatures298.15,303.15,308.15,and313.15K.Theexcessvolumes(V E),deviationsinisentropiccompressibilities (驻k s),acousticimpedances(驻Z),andrefractiveindices(驻n)werecalculatedfromtheexperimentaldata.Partialmolar volumes(V 0 准 ,2)andpartialmolarisentropiccompressibilities(K 0 准 ,2)ofxylenesinstyrenehavealsobeencalculated.The derivedfunctions,namely, V E , 驻k s , 驻Z, 驻n, V 0 准,2 ,and K 0 准,2 wereusedtohaveabetterunderstandingoftheintermolecular interactionsoccurringbetweenthecomponentmoleculesofthepresentliquidmixtures.Thevariationsofthese parameterssuggestthattheinteractionsbetweenstyreneand o鄄, m鄄,or p鄄xylenemoleculesfollowthesequences: p鄄xylene>o鄄xylene>m鄄xylene.Apartfromusingdensitydataforthecalculationof V E ,excessmolarvolumeswerealso estimatedusingrefractiveindexdata.Furthermore,severalrefractiveindexmixingruleshavebeenusedtoestimatethe refractiveindicesofthestudiedliquidmixturestheoretically.Overall,thecomputedandmeasureddatawereinterpreted intermsofinteractionsbetweenthemixingcomponents.

Physics and Chemistry of Liquids, 2016

ABSTRACT Experimental viscosities, η, for pure N,N-dimethylformamide (DMF) and acetone (ACT) and ... more ABSTRACT Experimental viscosities, η, for pure N,N-dimethylformamide (DMF) and acetone (ACT) and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 and 313.15 K. The deviations in viscosity, ∆η, Gibbs free energy of activation ∆G, entropies ∆S*, enthalpies ∆H of activation of viscous flow have been calculated. The determination of excess molar volumes, VηE, was calculated from the experimental viscosities for the binary mixtures. The conductor-like screening model is applied to interpret the intermolecular forces. The σ-profile is computed for the N,N-DMF and ACT with conductor-like screening model for real solvents. The experimental results were found to be in good agreement with the theoretical predictions. Moreover, viscosity data were calculated from the theoretical equations of Grunberg and Nissan, Hind et al. and Wilke for the entire systems. All results obtained were averaged experimentally and theoretically in terms of average deviations.

Journal of Molecular Liquids, 2015

ABSTRACT

Chemical Engineering Communications, 2016

Densities ρ, ultrasonic speeds u, and refractive indices n for pure n-hexane, methylacrylate (MA)... more Densities ρ, ultrasonic speeds u, and refractive indices n for pure n-hexane, methylacrylate (MA), ethylacrylate (EA), ethylmethacrylate (EMA), butylacrylate (BA), and of their 36 binary mixtures over the entire composition range were measured at 298.15, 303.15, 308.15, and 313.15 K. Using these data, the excess molar volumes, VE, deviations in isentropic compressibilities, Δks, deviations in molar refractions, ΔRm, and deviations in internal pressure, ΔPi, were calculated for the mixtures at given temperatures. Apparent molar volumes, Vϕ,2, and apparent molar compressibilities, Kϕ,2, of acrylic esters in n-hexane were also calculated. Partial molar volumes, , and partial molar isentropic compressibilities, , at infinite dilution were estimated. Moreover, the optical property and partial molar refraction, , of the systems at infinite dilution were examined. The variations of these parameters and of the optical property suggest that the strength of interactions in these mixtures follow the sequence: MA < EA < EMA < BA.

Journal of Surfactants and Detergents, 2016

Conductometric and surface tension techniques were employed to study the different mole fractions... more Conductometric and surface tension techniques were employed to study the different mole fractions of nonionic surfactants (TX-100 and Brij-35) with cetrimide. The standard Gibbs energies of micellization ($$\Delta G_{\text{m}}^{0}$$ΔGm0) and the Gibbs energies of transfer ($$\Delta G_{\text{trans}}^{0}$$ΔGtrans0) in the mixture of surfactants were also calculated; the micellization becomes more spontaneous on increasing the amount of nonionic surfactants in the mixture. It was observed that the values of excess surface concentration (Γmax) in surfactant mixtures decrease in comparison to the pure surfactants but the values of minimum area per surfactant molecule (Amin) increase in surfactant mixtures than in the pure ones. It was also observed that the values of the interaction parameter (β) are negative at all mole fractions. A gradual decrease in β with temperature is observed indicating the synergism between the two components and is attributed to the decrease in the electrostatic repulsion between the charged heads of the cationic surfactant as the nonionic surfactant is being intercalated into the micelle. The activity coefficients were found out to be less than unity confirming nonideality of the system and the negative values of excess free energy of mixing confirm that the mixed micelles formed were stable.

Journal of Molecular Liquids, 2016

Abstract Conductivity measurements were employed to investigate Kraft temperature (TK) of aqueous... more Abstract Conductivity measurements were employed to investigate Kraft temperature (TK) of aqueous solution of hexadecylpyridinium bromide (HPyBr) and HPyBr + glycine with added counter-ions. The pseudophase ion exchange model was adopted for HPyBr in pure water, glycine (Gly) and potassium bromide (KBr). The TK values for HPyBr increase with the increase in concentration of Gly and KBr. However, the experimental results show that the degree of counter-ion dissociation or ionization (α) remains nearly constant as the total surfactant concentration or counter-ion concentrations of salt are varied at the slower rate of micellar growth. Although the (α) is dependent on micellar shapes and changes as the micellar shape changes. The TK measurements for ionic micelles can be used to estimate counter-ion dissociation (α). The TK increase with increase in the counter-ion concentration because the solubility of surfactant is reduced at faster rate than critical micellar concentration (CMC). Kraft temperature measurements were employed to find the interaction between HPyBr and Glycine.

International Journal of Thermophysics, 2015

Densities \rho ρ and ultrasonic speeds u for pure diethylene glycol, 1-butanol, 2-butanol, an... more Densities \rho ρ and ultrasonic speeds u for pure diethylene glycol, 1-butanol, 2-butanol, and 1,4-butanediol and for their binary mixtures over the entire composition range were measured at 298.15 K, 303.15 K, 308.15 K, and 313.15 K. Using these data, the excess molar volumes, V^{E}_\mathrm{m}$$VmE, deviations in isentropic compressibilities, {\varDelta }k_{s}$$Δks, apparent molar volumes, V_{\phi ,i} Vϕ,i, partial molar volumes, \overline{V}_{m,i} V¯m,i, and excess partial molar volumes, \overline{V}_{m,i}^E V¯m,iE, have been calculated over the entire composition range, and also the excess partial molar volumes of the components at infinite dilution, \overline{V}_{m,i}^{E,\infty }$$V¯m,iE,∞ have been calculated. The excess functions have been correlated using the Redlich–Kister equation at different temperatures. The variations of these derived parameters with composition and temperature are presented graphically.

Asian Journal of Chemistry, 2013

Journal of Molecular Liquids

ABSTRACT

Asian Journal of Chemistry, 2015

ABSTRACT

Chemical Engineering Communications, 2014

ABSTRACT Experimental densities, ρ, refractive indices, n, and ultrasonic speeds, u, at various c... more ABSTRACT Experimental densities, ρ, refractive indices, n, and ultrasonic speeds, u, at various compositions and at various temperatures from (298.15 to 313.15) K for N,N-dimethylformamide + acetone binary mixtures were measured. From these results excess molar volumes (), deviations in refractive indices (Δn), isentropic compressibilities (Δk s), partial molar volumes (), and partial molar compressibilities (), of acetone in N,N-dimethylformamide were calculated. All the excess and deviation functions were fitted to Redlich–Kister polynomial equation to determine the fitting coefficients and the standard deviations. The values of and Δk s showed negative deviations, whereas excess Δn showed positive values over the entire range of concentrations and temperatures. The observed variations of these parameters, with concentration and temperature are discussed in terms of the intermolecular interactions and structural effects between the unlike molecules of the binary mixtures.

Journal of Surfactants and Detergents, 2013

Journal of Solution Chemistry, 2014

ABSTRACT Interactions between the cationic surfactant cetyltrimethyl ammonium bromide, dimethylsu... more ABSTRACT Interactions between the cationic surfactant cetyltrimethyl ammonium bromide, dimethylsulphoxide and lauric acid, have been studied in detail using volumetric and viscometric techniques. The critical micelle concentration (cmc) values have been determined using two different methods. The experimental data have been correlated against temperature and concentration using standard relations. From the density of the surfactant, the change of the apparent molar volumes at infinite dilution, Vo/ , apparent molar volumes at the cmc, Vcmc / , and apparent molar volumes upon micellization, DVm / , have been calculated. The viscosity data have been analyzed by means of the Jones–Dole equation in the pre-micellar region and the Einstein equation in the post-micellar region. The values of Falkenhagen coefficient and Jones–Dole coefficient thus obtained are used to interpret the solute–solute interactions in the pre-micellar region whereas Einstein’s equation is used to explore solute–solvent interactions in post micellar regions. Transition-state theory was applied to obtain the activation parameters of viscous flow, i.e., Gibbs energy of activation DGo�, per mole of solvent and solute. Moreover, the enthalpy DHo� and entropy of activation of viscous flow DSo� were computed in the pre-micelle regions. The obtained results indicate that the cmc strongly depends on the composition of the mixture. The results have been interpreted in the light of various interactions occurring among the components of the mixtures under the applied experimental conditions.

Korean Journal of Chemical Engineering, 2014

The intention of this review article is to review the knowledge about interactions in organic bin... more The intention of this review article is to review the knowledge about interactions in organic binary liquid mixtures. Molecular interactions in organic binary liquid mixtures are interesting due to their extensive use in many fields of solution chemistry. The thermodynamics of component molecules present in various systems interacting are particularly interesting because they display fantastic results. Studies of different organic liquid mixtures represent the different modes of interactions prevailing in the component molecules. The number of parameters required describing the properties of a given class of mixtures increases sharply with the number of segment types involved. In recent years, the theoretical and experimental investigations of interactions between unlike molecules have been conveniently carried out using excess thermodynamic functions. The properties of liquid mixtures depend on the forces between molecules and on the nature and volume of these molecules, and change with the composition of the mixtures. This change, in turn, is reflected in the thermodynamic properties of the mixtures. The influence of significant contributions of a chemical, physical and geometrical nature that change excess thermodynamic properties is considered and explained in detail.

The issue of the effects of corrosion on structural integrity of metal surfaces has been a questi... more The issue of the effects of corrosion on structural integrity of metal surfaces has been a question of concern for some time. The uses of chemical corrosion inhibitors are common in production and processing operations. Nevertheless, the challenge is to develop a new class of corrosion inhibitors to protect the materials, which are environment friendly under various conditions. Surfactants as corrosion inhibitors are environmentally acceptable and are very economical and easily available. The aim of this review article is to delineate the ability of surfactants to inhibit the corrosion on different metal surfaces. Various potential application and properties of different types surfactants have also been discussed. Various parameters like, effect of surfactant concentration, temperature and the mechanism of corrosion inhibition and mode of adsorption are also discussed in this review article.

Indian Journal of Pure & Applied Physics, 2008

Experimental viscosities, η of pure benzene, 1,2-dichloroethane (DCE), 1,1,2,2-tetrachloroethane ... more Experimental viscosities, η of pure benzene, 1,2-dichloroethane (DCE), 1,1,2,2-tetrachloroethane (TCE) and those of their binary mixtures, having benzene as a common component, have been measured over the whole composition range at 298.15, 303.15, 308.15, 313.15 and 318.15 K. The experimental η data were then fitted to standard polynomial against composition. Using η values, the deviations in viscosities, Δη, excess Gibbs free energies of activation of viscous flow, ΔG *E , entropies, ΔS* and enthalpies, ΔH* of activation of viscous flow have been calculated. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. Further, the excess molar volumes, V E were calculated using data for both the binary mixtures. Moreover, Grunberg-Nissan and Isdale's group contribution methods have been used to calculate the viscosities of mixtures and the results were discussed in terms of average percentage deviations (APD) in e...

Zeitschrift für Physikalische Chemie

The densities, ρ, viscosities, η and specific conductivities κ, of (0.0002, 0.0004, 0.0006 and 0.... more The densities, ρ, viscosities, η and specific conductivities κ, of (0.0002, 0.0004, 0.0006 and 0.0008 m) CTAB in 0.1 m aqueous valine, leucine and isoleucine were measured at different temperatures. The measured data were used to calculate various useful thermodynamic parameters. A complete characterization of any mixture can be performed by means of these thermodynamic properties. The apparent molar volume, ϕv, partial molar volume, phiv0\phi _v^0phiv0 and partial molar isobaric expansibilities, phiE0,\phi _E^0,phiE0, were calculated using density data. The viscosity data were analyzed using Jones–Dole equation to obtain viscosity coefficients, A- and B-, free energy of activation per mole of solvent, Δμ1°∗, and solute, Δμ2°∗, enthalpy, ΔH∗ and entropy, ΔS∗ of activation of viscous flow. Measuring the changes in these properties has been found to be an excellent qualitative and quantitative way to obtain information regarding the molecular structure and intermolecular interactions occurring in these...

International Journal of Thermophysics

The interactions of glycylglycine (di-peptide of glycine) also known as 2-[(2-aminoacetyl)amino] ... more The interactions of glycylglycine (di-peptide of glycine) also known as 2-[(2-aminoacetyl)amino] acetic acid with cationic surfactants cetylpyridinium chloride (CPC) and cetylpyridinium bromide (CPB) as a function of temperature in aqueous medium has been studied by well-know permutation of volumetric, ultrasonic and conductometric techniques. These measurements have been used to evaluate some useful thermodynamic parameters viz. apparent molar volumes, phiv\phi_{v}phivϕv, partial molar volumes, phivo\phi_{v}^{o}phivoϕvo, transfer volumes, phitextv0(tr)\phi_{\text{v}}^{0} (tr)phitextv0(tr)ϕv0(tr), partial molar expansibility, phiE0\phi_{E}^{0}phiE0ϕE0, hydration number, nH, apparent molal compressibility, phiK\phi_{K}phiKϕK, limiting partial molal adiabatic compressibility, phiK0\phi_{K}^{0}phiK0ϕK0. The specific conductivity (κ) was used to calculate the critical micellar concentration (cmc) and other physicochemical parameters of micellization of CPC/CPB with glycylglycine. The critical micelle concentration, cmc and limiting molar conductivity, varLambdamo\varLambda_{m}^{o}varLambdamoΛmo of the two surfactant systems were determined by using the conductivity data at 298.15 K, 303.15 K, 308.15 K and 313.15 K. The acquired data have been discussed as per various interactions taking place in the ternary system of CPC/CPB, glycylglycine and water.

Acta Physico-Chimica Sinica

： Thedensities(籽),ultrasonicspeeds(v),andrefractiveindices(n)ofbinarymixturesofstyrene(STY) with ... more ： Thedensities(籽),ultrasonicspeeds(v),andrefractiveindices(n)ofbinarymixturesofstyrene(STY) with m鄄, o鄄,or p鄄xylene,includingthoseoftheirpureliquids,weremeasuredovertheentirecompositionrangeatthe temperatures298.15,303.15,308.15,and313.15K.Theexcessvolumes(V E),deviationsinisentropiccompressibilities (驻k s),acousticimpedances(驻Z),andrefractiveindices(驻n)werecalculatedfromtheexperimentaldata.Partialmolar volumes(V 0 准 ,2)andpartialmolarisentropiccompressibilities(K 0 准 ,2)ofxylenesinstyrenehavealsobeencalculated.The derivedfunctions,namely, V E , 驻k s , 驻Z, 驻n, V 0 准,2 ,and K 0 准,2 wereusedtohaveabetterunderstandingoftheintermolecular interactionsoccurringbetweenthecomponentmoleculesofthepresentliquidmixtures.Thevariationsofthese parameterssuggestthattheinteractionsbetweenstyreneand o鄄, m鄄,or p鄄xylenemoleculesfollowthesequences: p鄄xylene>o鄄xylene>m鄄xylene.Apartfromusingdensitydataforthecalculationof V E ,excessmolarvolumeswerealso estimatedusingrefractiveindexdata.Furthermore,severalrefractiveindexmixingruleshavebeenusedtoestimatethe refractiveindicesofthestudiedliquidmixturestheoretically.Overall,thecomputedandmeasureddatawereinterpreted intermsofinteractionsbetweenthemixingcomponents.

Physics and Chemistry of Liquids, 2016

ABSTRACT Experimental viscosities, η, for pure N,N-dimethylformamide (DMF) and acetone (ACT) and ... more ABSTRACT Experimental viscosities, η, for pure N,N-dimethylformamide (DMF) and acetone (ACT) and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 and 313.15 K. The deviations in viscosity, ∆η, Gibbs free energy of activation ∆G, entropies ∆S*, enthalpies ∆H of activation of viscous flow have been calculated. The determination of excess molar volumes, VηE, was calculated from the experimental viscosities for the binary mixtures. The conductor-like screening model is applied to interpret the intermolecular forces. The σ-profile is computed for the N,N-DMF and ACT with conductor-like screening model for real solvents. The experimental results were found to be in good agreement with the theoretical predictions. Moreover, viscosity data were calculated from the theoretical equations of Grunberg and Nissan, Hind et al. and Wilke for the entire systems. All results obtained were averaged experimentally and theoretically in terms of average deviations.

Journal of Molecular Liquids, 2015

ABSTRACT

Chemical Engineering Communications, 2016

Densities ρ, ultrasonic speeds u, and refractive indices n for pure n-hexane, methylacrylate (MA)... more Densities ρ, ultrasonic speeds u, and refractive indices n for pure n-hexane, methylacrylate (MA), ethylacrylate (EA), ethylmethacrylate (EMA), butylacrylate (BA), and of their 36 binary mixtures over the entire composition range were measured at 298.15, 303.15, 308.15, and 313.15 K. Using these data, the excess molar volumes, VE, deviations in isentropic compressibilities, Δks, deviations in molar refractions, ΔRm, and deviations in internal pressure, ΔPi, were calculated for the mixtures at given temperatures. Apparent molar volumes, Vϕ,2, and apparent molar compressibilities, Kϕ,2, of acrylic esters in n-hexane were also calculated. Partial molar volumes, , and partial molar isentropic compressibilities, , at infinite dilution were estimated. Moreover, the optical property and partial molar refraction, , of the systems at infinite dilution were examined. The variations of these parameters and of the optical property suggest that the strength of interactions in these mixtures follow the sequence: MA < EA < EMA < BA.

Journal of Surfactants and Detergents, 2016

Conductometric and surface tension techniques were employed to study the different mole fractions... more Conductometric and surface tension techniques were employed to study the different mole fractions of nonionic surfactants (TX-100 and Brij-35) with cetrimide. The standard Gibbs energies of micellization ($$\Delta G_{\text{m}}^{0}$$ΔGm0) and the Gibbs energies of transfer ($$\Delta G_{\text{trans}}^{0}$$ΔGtrans0) in the mixture of surfactants were also calculated; the micellization becomes more spontaneous on increasing the amount of nonionic surfactants in the mixture. It was observed that the values of excess surface concentration (Γmax) in surfactant mixtures decrease in comparison to the pure surfactants but the values of minimum area per surfactant molecule (Amin) increase in surfactant mixtures than in the pure ones. It was also observed that the values of the interaction parameter (β) are negative at all mole fractions. A gradual decrease in β with temperature is observed indicating the synergism between the two components and is attributed to the decrease in the electrostatic repulsion between the charged heads of the cationic surfactant as the nonionic surfactant is being intercalated into the micelle. The activity coefficients were found out to be less than unity confirming nonideality of the system and the negative values of excess free energy of mixing confirm that the mixed micelles formed were stable.

Journal of Molecular Liquids, 2016

Abstract Conductivity measurements were employed to investigate Kraft temperature (TK) of aqueous... more Abstract Conductivity measurements were employed to investigate Kraft temperature (TK) of aqueous solution of hexadecylpyridinium bromide (HPyBr) and HPyBr + glycine with added counter-ions. The pseudophase ion exchange model was adopted for HPyBr in pure water, glycine (Gly) and potassium bromide (KBr). The TK values for HPyBr increase with the increase in concentration of Gly and KBr. However, the experimental results show that the degree of counter-ion dissociation or ionization (α) remains nearly constant as the total surfactant concentration or counter-ion concentrations of salt are varied at the slower rate of micellar growth. Although the (α) is dependent on micellar shapes and changes as the micellar shape changes. The TK measurements for ionic micelles can be used to estimate counter-ion dissociation (α). The TK increase with increase in the counter-ion concentration because the solubility of surfactant is reduced at faster rate than critical micellar concentration (CMC). Kraft temperature measurements were employed to find the interaction between HPyBr and Glycine.

International Journal of Thermophysics, 2015

Densities \rho ρ and ultrasonic speeds u for pure diethylene glycol, 1-butanol, 2-butanol, an... more Densities \rho ρ and ultrasonic speeds u for pure diethylene glycol, 1-butanol, 2-butanol, and 1,4-butanediol and for their binary mixtures over the entire composition range were measured at 298.15 K, 303.15 K, 308.15 K, and 313.15 K. Using these data, the excess molar volumes, V^{E}_\mathrm{m}$$VmE, deviations in isentropic compressibilities, {\varDelta }k_{s}$$Δks, apparent molar volumes, V_{\phi ,i} Vϕ,i, partial molar volumes, \overline{V}_{m,i} V¯m,i, and excess partial molar volumes, \overline{V}_{m,i}^E V¯m,iE, have been calculated over the entire composition range, and also the excess partial molar volumes of the components at infinite dilution, \overline{V}_{m,i}^{E,\infty }$$V¯m,iE,∞ have been calculated. The excess functions have been correlated using the Redlich–Kister equation at different temperatures. The variations of these derived parameters with composition and temperature are presented graphically.

Asian Journal of Chemistry, 2013

Journal of Molecular Liquids

ABSTRACT

Asian Journal of Chemistry, 2015

ABSTRACT

Chemical Engineering Communications, 2014

ABSTRACT Experimental densities, ρ, refractive indices, n, and ultrasonic speeds, u, at various c... more ABSTRACT Experimental densities, ρ, refractive indices, n, and ultrasonic speeds, u, at various compositions and at various temperatures from (298.15 to 313.15) K for N,N-dimethylformamide + acetone binary mixtures were measured. From these results excess molar volumes (), deviations in refractive indices (Δn), isentropic compressibilities (Δk s), partial molar volumes (), and partial molar compressibilities (), of acetone in N,N-dimethylformamide were calculated. All the excess and deviation functions were fitted to Redlich–Kister polynomial equation to determine the fitting coefficients and the standard deviations. The values of and Δk s showed negative deviations, whereas excess Δn showed positive values over the entire range of concentrations and temperatures. The observed variations of these parameters, with concentration and temperature are discussed in terms of the intermolecular interactions and structural effects between the unlike molecules of the binary mixtures.

Journal of Surfactants and Detergents, 2013

Journal of Solution Chemistry, 2014

ABSTRACT Interactions between the cationic surfactant cetyltrimethyl ammonium bromide, dimethylsu... more ABSTRACT Interactions between the cationic surfactant cetyltrimethyl ammonium bromide, dimethylsulphoxide and lauric acid, have been studied in detail using volumetric and viscometric techniques. The critical micelle concentration (cmc) values have been determined using two different methods. The experimental data have been correlated against temperature and concentration using standard relations. From the density of the surfactant, the change of the apparent molar volumes at infinite dilution, Vo/ , apparent molar volumes at the cmc, Vcmc / , and apparent molar volumes upon micellization, DVm / , have been calculated. The viscosity data have been analyzed by means of the Jones–Dole equation in the pre-micellar region and the Einstein equation in the post-micellar region. The values of Falkenhagen coefficient and Jones–Dole coefficient thus obtained are used to interpret the solute–solute interactions in the pre-micellar region whereas Einstein’s equation is used to explore solute–solvent interactions in post micellar regions. Transition-state theory was applied to obtain the activation parameters of viscous flow, i.e., Gibbs energy of activation DGo�, per mole of solvent and solute. Moreover, the enthalpy DHo� and entropy of activation of viscous flow DSo� were computed in the pre-micelle regions. The obtained results indicate that the cmc strongly depends on the composition of the mixture. The results have been interpreted in the light of various interactions occurring among the components of the mixtures under the applied experimental conditions.

Korean Journal of Chemical Engineering, 2014

The intention of this review article is to review the knowledge about interactions in organic bin... more The intention of this review article is to review the knowledge about interactions in organic binary liquid mixtures. Molecular interactions in organic binary liquid mixtures are interesting due to their extensive use in many fields of solution chemistry. The thermodynamics of component molecules present in various systems interacting are particularly interesting because they display fantastic results. Studies of different organic liquid mixtures represent the different modes of interactions prevailing in the component molecules. The number of parameters required describing the properties of a given class of mixtures increases sharply with the number of segment types involved. In recent years, the theoretical and experimental investigations of interactions between unlike molecules have been conveniently carried out using excess thermodynamic functions. The properties of liquid mixtures depend on the forces between molecules and on the nature and volume of these molecules, and change with the composition of the mixtures. This change, in turn, is reflected in the thermodynamic properties of the mixtures. The influence of significant contributions of a chemical, physical and geometrical nature that change excess thermodynamic properties is considered and explained in detail.