Amalendu Pal

Excess molar volumes, viscosities, and refractive indices of tetraethylene glycol dimethyl ether + dimethyl carbonate, + diethyl carbonate, and + propylene carbonate at 298.15 K

Excess molar volumes, viscosities, η, and refractive indices, nD, have been measured for the binary mixtures tetraethylene glycol dimethyl ether + dimethyl carbonate, + diethyl carbonate, and + propylene carbonate at 298.15 K and at atmospheric pressure over the complete composition range. The results are compared with those of previous investigations for binary mixtures containing esters of carbonic acid.

Excess Molar Volumes and Partial Molar Volumes of Dipropylene Glycol Monomethyl Ether + n-Alkanol Mixtures at 25°C

The excess molar volumes VE for binary liquid mixtures containing dipropylene glycol monomethyl ether and methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol have been measured using a continuous dilution dilatometer over the whole mole fraction range at 25°C at atmospheric pressure. VE are negative over the whole composition range except for the systems containing 1-pentanol, 1-hexanol, or 1-heptanol which are positve at every composition. VE increases in a positive direction with increase in chain length of the n-alcohol. The results have been used to estimate the excess partial molar volumes ViE of the components. The change of VE and ViE with composition and the number of carbon atoms in the alcohol molecule are discussed as a basis to understand some of the molecular interactions present in the mixtures:

Excess molar volumes and viscosities of mixtures of some n-alkoxyethanols with dialkyl carbonates at 298.15 K

Abstract Excess molar volumes V m E and viscosities η have been measured as a function of composition at atmospheric pressure and 298.15 K for nine {an alkoxyethanol+dimethyl carbonate (C 3 H 6 O 3 ), diethyl carbonate (C 5 H 10 O 3 ), or propylene carbonate (C 4 H 6 O 3 )} mixtures. The alkoxyethanols were 2-methoxyethanol (CH 3 OCH 2 CH 2 OH), 2-(2-methoxyethoxy)ethanol {CH 3 (OCH 2 CH 2 ) 2 OH}, and 2-{2-(2-methoxyethoxy)ethoxy}ethanol {CH 3 (OCH 2 CH 2 ) 3 OH}. The V m E for each of the carbonate mixtures studied decrease in magnitude as the polar head group of the alkoxyethanol increases. From the experimental results, deviation in the viscosity (Δln η ) have been calculated. The experimental results have been correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behaviour of the components.

Apparent Molar Volumes and Adiabatic Compressibilities of Some Amino Acids in Aqueous Sucrose Solutions at 298.15 K

Abstract Apparent molar volumes Vϕ and adiabatic compressibilities Kϕ,s of L-glycine, L-alanine, and L-valine in aqueous sucrose solutions ranging from pure water to 25 mass% of sucrose have been determined at 298.15 K from precise density and sound speed measurements. Partial molar volumes Vϕ0 and partial molar adiabatic compressibilities Kϕ,s0 of these amino acids at infinite dilution were evaluated. These values are required for calculating hydration number nH of amino acids. Transfer volumes ΔVϕ0 and transfer adiabatic compressibilities ΔKϕ,s0 at infinite dilution from water to aqueous sucrose solutions have been calculated. Transfer parameters have been discussed in terms of solute-cosolute interaction on the basis of a cosphere overlap model. Group contributions for the partial molar volumes and adiabatic compressibilities have been determined from the amino acids. All these results indicate that hydrophilic ionic group interactions are stronger than the hydrophilic-hydrophobic interactions in all the amino acids over the whole concentration range of sucrose solutions and decrease with the increase in size of side chain of amino acids.

Excess molar volumes and viscosities of binary mixtures of tetraethylene glycol dimethyl ether (tetraglyme) with chloroalkanes at 298.15 K

Abstract Excess molar volumes and viscosities of the binary mixtures of tetraethylene glycol dimethyl ether with dichloromethane, trichloromethane, and tetrachloromethane have been measured at 298.15 K and atmospheric pressure over the whole concentration range. The deviations in viscosities and excess energies of activation for viscous flow have been calculated from the experimental data. The Prigogine-Flory- Patterson (PFP) model have been used to calculateVmE, and are compared with experimental data. Bloomfield and Dewan model have been used to calculate viscosity coefficients and these are also compared with experimental data for the three mixtures. The results have been discussed in terms dipole-dipole interactions between tetraglyme and chloroalkanes and its magnitude decreasing with the dipole character of the molecule. A short comparative study with results for mixtures with polyethers and chloroalkanes is also presented.

Excess molar volumes and viscosities of binary mixtures of 2-butoxyethanol (butyl cellosolve) with chloroalkanes at 298.15 K

Abstract Molar excess volumes (VE) and dynamic viscosities (η) have been measured for non-electrolyte mixtures of 2-butoxyethanol (butyl cellosolve) with dichloromethane, trichloromethane or tetrachloromethane at 298.15 K over the whole concentration range. The excess volume curves are sigmoid with a maximum in the chloroalkane-rich region. From the experimental data excess viscosities (ΔElnη) and excess energies of activation for viscous flow ( ΔG ∗E ) have been derived. These values are positive over the entire range of composition for the system 2-butoxyethanol + trichloromethane and change sign from negative to positive for the remaining systems, 2-butoxyethanol + dichloromethane and + tetrachloromethane. The results for VE, ΔElnη and ΔG ∗E are discussed in terms of the interaction between components. The Flory theory of mixtures provides a useful basis for a qualitative interpretation of the results.

Excess molar volumes and viscosities of binary mixtures of some n-alkoxyethanols with pyrrolidin-2-one at 298.15 K

Abstract Excess molar volumes, VmE and viscosities, η have been measured as a function of mole fraction at atmospheric pressure and 298.15 K for binary mixtures of n-alkoxyethanol + pyrrolidin-2-one. The alkoxyethanols were 2-methoxyethanol (CH3OCH2CH2OH), 2-(2- methoxyethoxy)ethanol [CH3(OCH2CH2)2OH], 2-{2-(2-methyoxyethoxy)ethoxy}ethanol [CH3(OCH2CH2)3OH], 2-(2-ethoxyethoxy)ethanol [C2H5(OCH2CH2)2OH], and 2-(2-butoxyethoxy)ethanol [C4H9(OCH2CH2)2OH]. In all mixtures the excess molar volumes are negative over the entire composition range. From the experimental results, deviation in the viscosity, Δnη and excess energies of activation for viscous flow, ΔG∗E have been calculated. The experimental and calculated quantities are used to discuss the mixing behaviour of the components.

Excess molar volumes of an (1-alcohols+2,5-dioxahexane or 5,8,11-trioxapentadecane or 2-isopropoxyethanol) at 298.15 K

Abstract Excess molar volumes VE for binary liquid mixtures of an (1-alcohols+2,5-dioxahexane or 5,8,11-trioxapentadecane or 2-isopropoxy ethanol) have been measured as a function of compositions using a continuous-dilution dilatometer at 298.15 K and atmospheric pressure over the whole concentration range. The 1-alcohols were methanol, 1-propanol, and 1-pentanol. The VE for each of the mixtures studied are negative with the exception of 1-pentanol+2,5-dioxahexane, and +2-isopropoxyethanol and change sign for 1-propanol+2-isopropoxyethanol over the whole composition range. For each case, the VE increases as the chain length of the 1-alcohol increases.

Volumetric properties of binary mixtures of 2-alkoxyethanols with N,N-dimethylformamide and N,N-dimethylacetamide at 298.15 K

Abstract The excess molar volumes (VmE) for binary liquid mixtures of (2-alkoxyethanol +N,N-dimethylformamide or N,N-dimethylacetamide) have been measured with a continuous dilution dilatometer at 298.15 K and atmospheric pressure over the entire composition range. The 2-alkoxyethanols were 2-methoxyethanol (CH3OCH2CH2OH), 2-ethoxyethanol (C2H5OCH2CH2OH), and 2-butoxyethanol (C4H9OCH2CH2OH). The excess molar volumes are negative and symmetric over the entire range of composition for all mixtures. The results have been used to estimate the partial molar volumes Vmi of the components. The change of VmE and Vm i with composition and the number of alkyl chain-length in the alkoxyethanol molecule are discussed with reference to the nature of interactions between the component molecules.

Volumetric studies of some amino acids in binary aqueous solutions of MgCl2·6H2O at 288·15, and 308·15 K

Densities (ρ) of glycine, L-alanine, and L-valine in aqueous solutions of MgCl2-6H2O (0.1-0.8 mol kg-1) have been measured at 288.15, and 308.15 K. Apparent molar volumes (Vφ), and limiting partial molar volumes (Vφ0) of each amino acid have been calculated. These data were combined with the earlier reportedVφ0 values of glycine, L-alanine, and L-valine in aqueous MgCl2·6H2O solutions at 298.15 K in order to describe the temperature dependence behaviour of partial molar quantities. Group contributions to partial molar volumes have been determined for the amino acids. The trends of transfer volumes (△Vφ0) have been interpreted in terms of solute-cosolute interactions on the basis of a cosphere overlap model. Pair and triplet interaction coefficients have also been calculated from transfer parameters.