Excess properties and spectroscopic studies for binary system polyethylene glycol 600 + dimethyl sulfoxide at T =(298.15, 303.15,308.15, 313.15, and 318.15) K

The work presents density(ρ) and viscosity(η) data of binary system polyethylene glycol 600(PEG) + dimethyl sulfoxide(DMSO) over the entire concentration range at T =(298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. On the basis of density and viscosity values, the excess properties of PEG(1) + DMSO(2) mixtures, including excess molar volume(V_m^E), viscosity deviation(Δη), excess free energies of activation(ΔG^(*E)), and isobaric thermal expansion coefficient(αp), were calculated. At the same time, in order to conjecture the density viscosity under different conditions, the density and viscosity data were fitted with the corresponding formula. The calculated results of V_m^E, Δη, and ΔG^(*E) were fitted with the Redlich–Kister equation to derive coefficients and estimate the standard deviations(σ) between the experimental and calculated values. Moreover, the intermolecular interaction of PEG with DMSO was discussed on the basis of FTIR and UV–Vis spectral results of PEG(1) + DMSO(2) mixtures. The results indicated that there were the hydrogen bonding and interactions of hydroxyl hydrogen atoms in PEG with oxygen atoms in DMSO.

Study on Excess Thermodynamic Parameters and Theoretical Estimation of Ultrasonic Velocity Using Scaled Particle Theory in Binary Liquid Mixtures of 2-Methyl-2-propanol and Nitriles at Different Temperatures

Density, ρ, ultrasonic speed, u, and viscosity, η, of binary mixtures of 2-methyl-2-propanol (2M2P) with acetonitrile (AN), propionitrile (PN) and butyronitrile (BN) including those of pure liquids are measured over the entire composition range at temperatures 298.15, 303.15 and 308.15 K. From these experimental data, the excess available volume, E a V , excess free volume, E f V , excess isothermal compressibility, E T β , excess thermal expansion coefficient, E α , and excess internal pressure, E i π , are calculated. The variation of these properties with composition and temperature are discussed in terms of molecular interactions between unlike molecules of the mixtures. It is found that the values of E a V , E f V , E T β and E α are positive and those of E i π are negative for all the mixtures at each temperature studied, indicating the presence of weak interactions between 2M2P and AN/PN/BN molecules. The variations of E a V , E f V , E T β , E α and E i π values with composition indicate that the interactions in these mixtures follow the order: AN<PN<BN, i.e., the 2M2P-nitrile interaction decreases with the increase of alkyl chain length in these nitrile molecules. In addition, the theoretical ultrasonic velocity is calculated using the scaled particle theory and compared with the experimental values.

Densities and surface tensions of ionic liquids/sulfuric acid binary mixtures

The densities and surface tensions of [Bmim][TFO]/H2SO4, [Hmim][TFO]/H2SO4 and [Omim][TFO]/H2SO4 binary mixtures were measured by pycnometer and Wilhelmy plate method respectively. The results show that densities and surface tensions of the mixtures decreased monotonously with increasing temperatures and increasing ionic liquid （IL） molar fraction. IL with longer alkyl side-chain length brings a lower density and a smaller surface tension to the ILs/H2SO4 binary mixtures. The densities and surface tensions of the mixtures are fitted well by Jouyban-Acree （JAM） model and LWW model respectively. Redlich-Kister （R-K）equation and modified Redlich-Kister （R-K） equation describe the excess molar volumes and excess surface tensions of the mixtures well respectively. Adding a small amount of ILs （XIL 〈 0.1 ） into sulfuric acid brings an obvious decrease to the density and the surface tension. The results imply that the densities and surface tensions of IL5/H2SO4 binary mixtures can be modulated by changing the IL dosage or tailoring the IL structure.

Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils

Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. The adsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order: atrazine ≈prometon<prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties of triazine. The Freundlich adsorption constants, K f, showed to have good correlation with organic matter(OM%) of soils for each of these herbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.

Study of intermolecular interactions in binary mixtures of methyl acrylate with benzene and methyl substituted benzenes at different temperatures:An experimental and theoretical approach

The ultrasonic speeds,u and viscosities,ηof the binary mixtures of methyl acrylate with benzene,toluene,o-xylene,m-xylene,p-xylene,and mesitylene over the whole mole fraction range were measured at six different temperatures and at atmospheric pressure.From the experimental data,the excess isentropic compressibility,κ_(s)^(E),excess ultrasonic speed,u^(E),excess molar isentropic compressibility,K_(s,m)^(E),excess specific impedance,Z^(E)and deviations in viscosity,Δηhave been calculated.The partial molar isentropic compressions,K_(s,m,1) and K_(s,m,2),and excess partial molar isentropic compressions,K_(s,m,1)^(-E) and K_(s,m,2)^(-E) over the whole composition range,partial molar isentropic compressions,K_(s,m,1)^(-)and K_(s,m,2)^(-),and excesspartial molar isentropic compressions,K_(s,m,1)^(-E) and K_(s,m,2)^(-E)of the components at infinite dilution have also been calculated.The results specified the existence of weak interactions between unlike molecules,and these interactions follow the order:benzene>toluene>p-xylene>m-xylene>o-xylene>mesityle ne.The magnitude of interactions was found to be dependent on the number and position of the methyl groups in these aromatic hydrocarbons.

Plasmonic gold nanoshell induced spectral effects and refractive index sensing properties of excessively tilted fiber grating

We demonstrate a fiber refractive index（RI） sensor based on an excessively tilted fiber grating（ExTFG）immobilized by large-size plasmonic gold nanoshells（GNSs）. The GNSs are covalently linked on ExTFG surface.Experimental results demonstrate that both the intensity of the transverse magnetic（TM） and transverse electric（TE） modes of ExTFG are significantly modulated by the localized surface plasmon resonance（LSPR） of GNSs due to the wide-range absorption band. The wavelength RI sensitivities of the TM and TE modes in the low RI range of 1.333–1.379 are improved by ～25% and ～14% after GNSs immobilization, respectively, and the intensity RI sensitivities are ～599%/RIU and ～486%/RIU, respectively.

Dielectric relaxation study of aqueous ethylene glycol mono-methyl ether(EGME)with water using time domain reflectometry technique in the frequency range 10MHz to 50 GHz

The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined using Time Domain Reflectometry(TDR)technique in the frequency range 10MHz to 50 GHz.The complex permittivity spectra for EGME-water were fitted in the Cole-Davidson model.The Static dielectric constant(ε_(0)^(E)),Relaxation time(τ),effective Kirkwood correlation factor(g_(eff)),excess permittivity(ε_(0)),thermodynamic parameters(activation enthalpy and activation entropy)and Bruggeman factor(f_(B))have been calculated by the nonlinear least square fit method.The intermolecular interactions between EGME-water binary mixtures suggest the nonlinear behavior of dielectric parameters.The contribution of hydrogen bonding interactions among the solute-solvent mixtures is confirmed by Excess properties and Bruggeman factor.

Volumetric and viscometric properties of aqueous 1,2-dimethylethylenediamine solution for carbon capture application

The present work investigates the volumetric and viscometric properties of an aqueous solution of 1,2-dimethylethylenediamine(DEEDA)over an entire concentration range and an absorber operating temperature range of 313.15K-333.15K at atmospheric pressure.The investigated volumetric properties included the density,excess molar volume,partial molar volume,and the investigated viscometric properties included the viscosity,viscosity deviation,free energy for activation of viscous flow,excess free energy for activation of viscous flow,and excess entropy for activation of viscous flow.The results indicated that there are strong intermolecular interactions and suitable molecular packing in the binary DEEDA-water mixture.Hence,the mixture was found to deviate from a real mixture according to the calculated excess properties.The DEEDA solvent's preliminary volumetric and viscometric properties revealed convincing potential as a novel amine for carbon capture.Additionally,the Redlich-Kister-based correlations showed favorable correlative performance for excess molar volume,viscosity deviation,and excess entropy for activation of viscous flow.