A volumetric and acoustic study of pseudo-binary mixtures of (water + 1,3-propanediol + 3-butoxypropan-1-amine) from T = (283.15 to 303.15) K

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Highlights

  • Density and sound speed of pseudo-binary mixtures of (water + 1,3-propanediol + 3-butoxypropan-1-amine).

  • Effect of adding a small quantity of the amphiphile 3-Butoxypropan-1-amine to the aqueous 1,3-propanediol mixtures.

  • The role of the hydrophobic characteristics of 3-Butoxypropan-1-amine in the aggregation process.

  • Useful information gathered from excess molar expansions and excess partial molar volumes and isentropic compressions.

Abstract

Due to the relevant role that polyols play either as solvents or additives in many industries thermodynamic properties of aqueous mixtures of these compounds have been largely studied. In this work we aim to study the effect of adding a small amount of 3-butoxypropan-1-amine on the volumetric properties of the binary (water + 1,3-propanediol) mixture. Densities and speeds of sound of the ternary (pseudo-binary) mixture, (water + 1,3-propanediol + 3-butoxypropan-1-amine), were measured at five different temperatures ranging from T = (283.15 to 303.15) K. Excess molar, volumes, isobaric expansions and isentropic compressions of the system, as well as the excess partial molar, volumes and isentropic compressions for water and 1,3-propanediol were derived. Some functions of transference of the 1,3-propanediol and water from the binary{water + 1,3-propanediol} to the ternary mixtures were estimated. The interpretation of the results was made in terms of changes in aggregation patterns and hydration.

Introduction

It is well known the importance of polyols, and in particular diols, in many domains. In biophysics and pharmaceutical industry they are used in preventing the denaturation of proteins and as additives to many drugs, food and cosmetic products because they have been considered compatible co-solvents for proteins [1], [2], [3]. In chemical industry and engineering they are used in the production of polyurethanes and polyethers [4], [5] and as compounds that can prevent the freezing of water and oil with several applications in refrigeration and regulation of temperature [6], [7].

Thermophysical and in particular volumetric properties of aqueous mixtures of diols have been measured by various authors since some time ago [8], [9], [10].

Aqueous mixtures of amphiphiles have been one of the main scientific interests of our research group, trying to understand the mutual influence of amphiphiles in the water structure (hydration) or of water on the organic molecules aggregation or conformation [11], [12], [13], [14], [15], [16], [17]. Effects of changing the amphiphilic groups (including different types of amines, hydroxyl and alkoxy), branching or the chain length have been fructuous to clarify types of hydration and aggregation patterns observed with changing composition and temperature. In recent works [18], [19], [20] we have studied volumetric, acoustic and energetic properties of the aqueous binary mixture {water + 3-butoxypropan-1-ol (BPA)} where we could characterize different types of hydration and identify the threshold of aggregation pattern changing, advancing some of their characteristics.

In this work we aim to study the effect of adding a small amount of BPA on thermodynamic properties of the binary mixture {water +1,3-propanediol (1,3-PD)}. Densities and speeds of sound of the ternary (pseudo-binary) mixture, {water (1) +1,3-PD (2) + BPA (3)}, were measured at five different temperatures ranging from T = (283.15 to 303.15) K. Excess molar, volumes, isobaric expansions and isentropic compressions as well as excess partial molar, volumes and isentropic compressions (including values at infinite dilution) were derived and differences between the volumetric behaviour of these pseudo binary mixtures and the binary (water +1,3-PD) mixtures, were compared and interpreted.

Section snippets

Materials and solutions preparation

3-Butoxypropan-1-amine (BPA), CAS Registry No. 16499-88-0, was obtained from Sigma-Aldrich with purity quoted >0.99, in mass fraction, and used without further purification. The water content was determined by Karl-Fischer method and was found to be <0.001 in mass fraction. 1,3-Propanediol (1,3-PD), CAS number 504–63-2, was supplied by Merck, with purity quoted >0.98, in mass fraction, and used without further purification. The water content was determined by Karl-Fischer method and was found

Density and sound speed

Table 2 summarizes the experimental density and experimental differences, Δu = u’−u0, measured in the ternary system {water (1) + 1,3-PD (2) + BPA (3)}, at the five temperatures. u’ refers to the sound speeds of mixtures and pure 1,3-PD and u0 refers to water. The true u values were then obtained adding the reference sound speed values for water (uref [23]) to Δu. This procedure avoids systematic deviations of the sound speed meter.

For the pure 1,3-PD, comparisons with available literature

Excess molar, volumes, isobaric expansions and isentropic compressions

As it is well known, excess molar properties are defined by Eq. (1),ZmE=Zm-Zmidwhere ZmE is the difference between values for the molar property of the real mixture, Zm, and those for an ideal mixture, at the same temperature, pressure and composition of the real mixture, Zmid. In our case Zm stands for: Vm (molar volume), EP,m=Vm/TP (molar isobaric expansion), CP,m (molar isobaric heat capacity), KT,m=VmkT (molar isothermal compression) and KS,m=VmkS, (molar isentropic compression) where kT

Conclusions

Densities and sound speeds were measured in the ternary (pseudo-binary) {water (1) + 1,3-propanediol (1,3-PD) (2) + 3-butoxypropan-1-amine (BPA) (3)} mixtures, across the whole 1,3-PD composition range. The composition of the mixed solvent, {water (1) +BPA (3)}, was fixed at fm = x3/(1−x2) = 0.0062.

This volumetric study aimed to explore the effect of adding a small amount of an amphiphilic molecule, BPA, with a similar structure as 1,3-PD, to the binary {water + 1,3-PD} mixture. Excess molar,

Acknowledgements

Financial support from Fundação para a Ciência e a Tecnologia, Portugal, under projects UID/MULTI/00612/2013 and UID/QUI/00100/2013 is greatly appreciated.

References (36)

  • D.J. McClements

    Curr. Opin. Colloid Interface Sci.

    (2004)
  • A. Rani et al.

    Process Biochem.

    (2016)
  • I. Diez-Garcia et al.

    Eur. Polym. J.

    (2018)
  • E.M. Christ et al.

    Biomacromolecules

    (2015)
  • A.F.S.S. Mendonça et al.

    J. Chem. Thermodyn.

    (2004)
  • I.M.S. Lampreia et al.

    J. Chem. Thermodyn.

    (2004)
  • A.F.S. Santos et al.

    J. Chem. Thermodyn.

    (2009)
  • I.M.S. Lampreia et al.

    J. Chem. Thermodyn.

    (2012)
  • L.M.V. Pinheiro et al.

    J. Chem. Thermodyn.

    (2013)
  • I.M.S. Lampreia et al.

    J. Chem. Thermodyn.

    (2015)
  • L.C.S. Nobre et al.

    J. Chem. Thermodyn.

    (2017)
  • I.M.S. Lampreia et al.

    J. Chem. Thermodyn.

    (2011)
  • K. Zemánková et al.

    Fluid Phase Equilib.

    (2013)
  • C.M. Romero et al.

    J. Chem. Thermodyn.

    (2008)
  • M.M. Alavianmehr et al.

    Fluid Phase Equilib.

    (2014)
  • F. Martins et al.

    J. Mol. Liq.

    (2017)
  • A.F.S. Santos et al.

    Thermochim. Acta

    (2011)
  • T. Mezhebovsky et al.

    Biopharm. Int.

    (2016)
  • Cited by (0)

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