Studies of intrinsic volumes of ethylene glycol and polyethylene glycol–300 molecules in aqueous solutions at 298.15 K: Application of Tammann–Tait–Gibson (TTG) equation of state

• Published in: Journal of molecular liquids 2022-01, Vol.346, p.117056, Article 117056
• Main Authors: Shaikh, Vasim R., Mahire, Rahul R., Borase, Namrata V., Patil, Swati D., Patil, Pankaj D., Patil, Kesharsingh J.
• Format: Article
• Language: English
• Subjects: Apparent molar volume and expansivity; Internal pressure of solutions, solute–solute/solute–solvent interactions; Polyethylene glycols; Transfer volume
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2021.117056

Molecules with an internal hydrogen bond can only form linear aggregates similar to those formed by monohydric alcohols. [Display omitted] •Densities for PEG-200/300/400/600 in water at T (=288.15–308.15 K).•For PEG-200 and PEG-600, Eϕ0 values decrease as a function of temperature.•Internal pressure variation with molality of EG and PEG-300 in water are studied.•Intrinsic volumes for EG and PEG-300 are estimated using TTG equation.•V¯20E values are found to be –16.1 and –63.8⋅10–6 m3⋅mol−1 for EG and PEG–300. Systemic density (ρ) measurements have been carried–out for aqueous solutions of polyethylene glycols (PEG's) with the molar mass 200, 300, 400 and 600 D at (288.15, 293.15, 298.15, 303.15 and 308.15) K and at ambient pressure of 0.1 MPa in dilute solute concentration region (0.0119–0.4941 mol⋅kg−1). The ρ data are used to obtain the apparent molar volume (Vϕ) and partial molar volume (V¯2) of studied PEG's in aqueous solutions at finite concentration as well as at infinitely dilute solutions (Vϕ0) at studied temperatures. The coefficient of thermal expansion (α) for solutions, apparent molar expansivity (Eϕ) and limiting apparent molar expansivity (Eϕ0) for solutes are calculated at 293.15, 298.15 and 303.15 K. The densities of studied PEG's in carbon tetrachloride (CCl4) medium are also measured at 298.15 K. The transfer volume (ΔtrVϕ0) for PEG from pure liquid state to CCl4 and to water as solvent are estimated. The literature data of sound velocity (u), coefficient of thermal expansion (α) and specific heat capacity (CP) for solutions have been utilized to obtain thermodynamic properties like adiabatic compressibility (βad) and isothermal compressibility (βT) in case of aqueous solutions of ethylene glycol (EG) and PEG–300 at 298.15 K. The data are further utilized to obtain apparent molar adiabatic compressibility (KϕS) and apparent molar isothermal compressibility (KϕT) for EG and PEG–300 solute molecules at finite and at infinitely dilute solute concentration (KϕS0 and KϕT0, respectively). Further, the data of KϕT, α and CP data have been utilized to estimate internal pressure Pi (=∂U∂VT) of solutions containing EG and PEG–300 molecules as a function of concentration. The intrinsic volumes (Vint.) of these molecules have been calculated by applying Tammann–Tait–Gibson (TTG) equation of state. It is being observed that intrinsic volume differs appreciably from the value based upon EG and PEG–300 in a liquid state as a standard state. The excess