Effect of properties of the N,N-dimethylformamide–methanol and N,N-dimethylformamide–water mixtures on the solution enthalpy of glymes in these mixtures at 298.15 K

Accepted Manuscript Title: Effect of properties of the N,N-dimethylformamide-methanol and N,N-dimethylformamide-water mixtures on the solution enthalpy of glymes in these mixtures at 298.15 K Author: Malgorzata Jozwiak Magdalena Szylberg Henryk Piekarski Kinga Kustrzepa Andrzej Jozwiak PII: DOI: Reference:

S0040-6031(17)30052-7 http://dx.doi.org/doi:10.1016/j.tca.2017.03.001 TCA 77692

To appear in:

Thermochimica Acta

Received date: Accepted date:

30-9-2016 17-2-2017

Please cite this article as: M. J´oz´ wiak, M. Szylberg, H. Piekarski, K. Kustrzepa, A. J´oz´ wiak, Effect of properties of the N,N-dimethylformamide-methanol and N,N-dimethylformamide-water mixtures on the solution enthalpy of glymes ¨ ¨/>K, Thermochimica Acta (2017), in these mixtures at 298.15
Effect of properties of the N,N-dimethylformamide-methanol and N,N-dimethylformamidewater mixtures on the solution enthalpy of glymes in these mixtures at 298.15 K Małgorzata Jóźwiaka*, Magdalena Szylberga, Henryk Piekarskia, Kinga Kustrzepaa, Andrzej Jóźwiakb a

University of Lodz, Faculty of Chemistry, Department of Physical Chemistry, Pomorska 165,

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90-236 Lodz, Poland b

University of Lodz, Faculty of Chemistry, Department of Organic Chemistry, Tamka 12, 91-

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403 Lodz, Poland

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*corresponding author, phone number: +48 42 635 58 25, e-mail: [email protected]

Highlights

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Enthalpies of solution of linear polyethers in DMF+MeOH were measured; Enthalpies of solvation of linear polyethers in DMF, MeOH and W was analyzed, The effect of base properties of the mixture on the solution enthalpy was discussed,

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The obtained results were compared with analogous data in DMF+W mixtures.

Abstract

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The enthalpies of solutions of diglyme, triglyme, tetraglyme, pentaglyme and hexaglyme in N,N-dimethylforamide-methanol mixtures (DMF+MeOH) have been measured at 298.15 K. On the basis of the data obtained, the effect of the acid-base properties of the DMF+MeOH mixtures on the standard solution enthalpy of glymes in these mixtures has been analyzed. The results obtained have been compared with analogous data obtained for N,N-

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dimethylformamide-water (DMF+W) mixtures.

Keywords: Glymes, N,N-dimethylforamide-methanol mixtures, N,N-dimethylforamide-water mixtures, Enthalpy of solution, Acid-base properties.

1. Introduction Linear

polymers

known

as

glymes

represented

by

the

general

formula

CH3O(CH2CH2O)nCH3 are dissected equivalents of cyclic ethers including crown ethers. These compounds are widely used, mainly as solvents. They can also be used in a

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nucleophilic substitution reaction [1], in biological systems [2-4] and as catalysts in the phase transfer catalysis [5]. The compounds mentioned, as crown ethers, can form complexes with metal cations [6-9]. These complexes, however, are weaker than the complexes formed by the respective crown ethers [6,10,11]. A wide use of both the compound groups mentioned is due to their molecular structure. Linear polyethers as well as cyclic ethers exhibit hydrophilichydrophobic properties. In pure water and mixed aqueous-organic solvents (in the range of

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high water content) behave in a particular way because of hydrophobic hydration of these compounds [4,12].

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For some time we have investigated the effect of different properties of the mixed aqueousorganic solvents on the standard solution enthalpy of the compounds with hydrophilic-

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hydrophobic properties. We took into account the following properties of mixtures: energetic features expressed as an excess enthalpy of mixing (HE), structural parameters that

are

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reflected in excess volume (VE) [13] and acid-base properties that are described by KamletTaft’s parameter BKT ( Lewis’ basicity) and by standardized Dimroth-Reichardt’s parameter ETN (Lewis’ acidity) [14].

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We paid particular attention to the study of the standard solution enthalpy of compounds with hydrophilic-hydrophobic properties, i.e. cyclic ethers and glymes in mixtures of N,N-

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dimethylformamide with water (DMF+W). According to some authors, in this mixed solvent energetic effects associated with hydrophilic and hydrophobic hydration of DMF molecules

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compensate each other [15,16]. Therefore, a mixture of DMF+W is used to study the process of hydrophobic hydration of the dissolved compounds. [12,15-17]. Recently we have studied the effect of various properties of mixed non-aqueous solvents, i.e. N,N-dimethylformamide+methanol (DMF+MeOH) on the standard solution enthalpy. In these mixtures, no hydrophobic hydration of a solute process occurs, but a solvophobic

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solvation may occur [18,19]. In addition, the molecules of methanol are able to self-associate as those of water. In the present work that is a continuation of our previous studies [20-23], we intended to examine the effect of the exchange of water molecules to methanol ones in the mixtures with N,N-dimethylformamide (DMF) on the standard solution enthalpy of linear polyethers. We also studied the effect of acid-base and structural-energetic properties of mixtures DMF+MeOH on the standard solution enthalpy of glymes in this mixture and the results obtained were compared with analogous results obtained in the mixtures of DMF and water (DMF+W).

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2. Experimental Section 2.1. Materials Suppliers, purity, a method of purification and water contents in the compounds used for measurements

(diglyme,

triglyme,

tetraglyme,

pentaglyme,

hexaglyme,

N,N-

dimethylformamide and methanol) are shown in Table 1.

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2.2. Methods

The measurements of heat of solution of glymes in the DMF+MeOH mixtures have been

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performed at (298.15 ± 0.01) K using an “isoperibol” type calorimeter as described in the literature [26]. The calorimeter was verified on the basis of the standard enthalpy of solution

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of urea and KCl (Calorimetric standard US, NBS) [27,28] in water at (298.15 ± 0.005) K as was described in our recent publication [29]

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The concentrations of glymes in the mixtures were for: diglyme (from 0.00586 to 0.01236) mol kg-1 (the mole per kilogram of solvent), triglyme (from 0.00386 to 0.01016) mol kg-1, tetraglyme (from 0.00354 to 0.01171) mol kg-1, pentaglyme (from 0.00287 to 0.00937)

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mol kg-1 and hexaglyme (from 0.00274 to 0.00736) mol kg -1. Six to eight independent measurements were performed for each investigation systems. The uncertainties in the

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measured enthalpies did not exceed ± 0.5% of the measured value. No concentration dependence (outside the error limits) of the measured enthalpies of solution was observed within the examined range of the glyme content. For this reason, the standard solution

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enthalpy ΔsolH o was calculated as a mean value of the measured enthalpies (Table 2). The effect of water content in the samples of glymes on the values of the solution standard enthalpy is within the limits of error. We also tried to make measurements of the dissolution heat of monoglyme in the mixtures of DMF+MeOH, but the thermal effect was too small.

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In Table 2 the literature values of the standard solution enthalpy for diglyme, triglyme and tetraglyme in methanol are presented. The difference is outside the limits of error. It is not easy to explain this fact.

3. Results and Discussion Fig. 1 presents the standard solution enthalpy of glymes in the DMF+MeOH mixtures as a function of mole fraction of methanol (xMeOH). As seen, in the range of high DMF content i.e. xMeOH < 0.6, the dissolution process is exothermic. At xMeOH ≈ 0.6 the standard solution enthalpy of glymes is nearly equal to zero and the effect of the process is changed from

3 Page 3 of 29

exothermic to endothermic. Thus, the addition of methanol to DMF increases the endothermic effect of the dissolution of glymes. It may therefore be assumed that in the area of xMeOH < 0.6, glymes molecules are preferentially solvated by DMF molecules. Using the data of the standard solution enthalpy of glymes (3 ≤ n–O– ≤ 7), (n–O– is the number of oxygen atoms in the glymes molecules), monoglyme (n–O– = 2) in DMF [12], glymes (2 ≤ n–O– ≤ 7) in water [12,17] examined in this paper and data of the evaporation

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enthalpy of glymes [12], the solvation enthalpy of glymes in DMF, MeOH and W were calculated. It is noted that the standard solvation enthalpy of glymes in each of these three

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solvents depends linearly on the number of oxygen atoms in glymes molecules Eq. (1).

(1)

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solvH 0  a  b  nO 

The parameters of Eq. (1) determined are presented in Table 3. Comparing the coefficients of

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Eq. (1), it can be seen that they are very similar in pure DMF and MeOH, but they differ substantially in water. It can mean that the interactions of glymes molecules with water molecules are significantly different from the interaction of glymes molecules with the

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molecules of MeOH and DMF. This was expected because of the hydrophobic hydration of glymes molecules in water. Also, one can note that the oxygen atoms in the glymes molecules

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can form hydrogen bonds with water molecules [4]. In order to compare changes in the standard solution enthalpy of glymes caused by changes in

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the composition of the mixed solvent of DMF+MeOH and DMF+W, in Fig. 2 the transfer enthalpy of glymes from DMF to the mixtures DMF+MeOH and DMF+W are presented, which can be calculated using the Eqs. (2) and (3): (2)

tr H 0 (DMF DMF W)  solH 0 (DMF W)  solH 0 (DMF)

(3)

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tr H 0 (DMF DMF MeOH)  solH 0 (DMF MeOH) solH 0 (DMF)

where:  tr H 0 (DMF DMF MeOH),  tr H 0 (DMF DMF W) are the transfer enthalpy of glymes from DMF to the DMF MeOH and DMF W mixtures, respectively, solH o (DMF MeOH) ,  solH o (DMF W) are the standard solution enthalpy of glymes in

the DMF MeOH and DMF W mixtures, respectively, and  solH o (DMF) is the standard solution enthalpy of glymes in DMF.

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As shown in Fig. 2, in a region of a high DMF content in mixtures (DMF+MeOH and DMF+W), the transfer enthalpy slightly increases linearly, indicating that no major change in the interaction occurs due to the addition of methanol or water to DMF. The values of the standard solution enthalpy of glymes in DMF+MeOH are growing systematically (this process is becoming more endothermic) together with the increase in

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methanol content in the mixture within the whole range of composition of the mixed solvent.

This also demonstrates that the increase in MeOH content in the mixture with DMF makes it

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difficult for glymes molecules to be incorporated into the existing structure of DMF+MeOH mixture. The phenomenon observed may be caused by the self-association of methanol [32].

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As seen in Fig. 2, in the case of DMF+W mixtures, the addition of water to DMF causes a slight increase in the endothermic effect of the dissolution process in the range up to xDMF ≈

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0.6. It is known that in the area of xDMF ≈ 0.6, the DMF+W mixture is the most packed and the interactions of water molecules with DMF molecules are the strongest [33]. Hence, the inclusion of glymes molecules in a mixture with such a composition is made difficult. With

M

further increase in the water content, xw > 0.6, a rapid increase in the exothermic effect of the dissolution process is visible. Such a shape of the standard solution enthalpy curve as a

ed

function of the water contend in the mixtures is a characteristic if the examined solute is hydrophobically hydrated [12,13,15,16,29].

We made the assessment of the effect of the acid-base properties of DMF+MeOH on the

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standard solution enthalpy of linear poliethers in this mixture. Lewis’ basicity is expressed by Kamlet-Taft’s parameter BKT. The values of BKT for DMF+MeOH mixtures were taken from literature [34]. Lewis’ acidity is expressed by the standardized Dimroth-Reichardt’s parameter

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ETN . The values of ETN were calculated using Eq. (4) ETN  [ ET (solvent )  ET (TMS)] /[ ET (water)  ET (TMS)]

(4)

where: ET is the Dimroth-Reichardt parameter and TMS is tetramethylsilan. The values of ET for DMF+MeOH mixtures, TMS and water have been taken from literature [35–37], respectively. The values of ET and BKT coefficients for each of the particular mixtures were taken from the literature [34,35]. Fig. 3 shows the acid-base properties of the DMF+MeOH as a function of the molar fraction of MeOH in the mixtures. For comparison, in the same Fig. 3 the acid-base properties 5 Page 5 of 29

of the DMF+W mixture as a function of W in the mixture are presented, which were taken from the literature [14]. As can be seen in Fig. 3, the acid-base properties of DMF+W mixture change more significantly than in DMF+MeOH. We attempted to investigate the correlations described by Eqs. (5–7)): (5)

solH o  Qo  bBKT

(6)

ip t

solH o  Qo  aETN

solH o  Qo  aETN  bBKT

cr

(7)

where: Qo is the value of the given property in the absence of the solvent effect, a indicates

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the contribution of the acid properties and b indicates the contribution of the base properties to the variation of the standard enthalpy of solution.

It appears that the standard solution enthalpy of glymes in DMF+MeOH mixtures depends

an

on the basic properties of the mixture (Eq. 6), similar as in the case of cyclic ethers in the same mixtures [38]. In DMF+W mixture the standard enthalpy of glymes depends on both

M

basic and acidic properties of the mixture (Eq. 7), as in the case of cyclic ethers [38]. The values of the parameters obtained in Eqs. (6) and (7) are collected in Table 4 and

Eqs. (6) and (7) are quite good.

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Table 5, respectively. The values of R2, SD and P confirm that the dependences described by

Furthermore, we noticed that the calculated parameters Qo, a and b depended linearly on the

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number of oxygen atoms (n–O–) in the glymes molecules (for DMF+MeOH Eqs. (8) and (9), and for DMF+W Eqs. (10–12)).

R2 = 0.99645

SD = 0.8466

P <0.0001

(8)

b=

11.370(1.959)– 11.586(0.377)∙n–O–

R2 = 0.99683

SD = 1.1923

P <0.0001

(9)

Qo = –42.395(2.550)–23.419(0.530)∙n–O–

R2 = 0.99796

SD = 2.2165

P <0.0001 (10)

a=

26.583(2.485)+10.612(0.516)∙n–O–

R2 = 0.99062

SD = 2.1600

P <0.0001 (11)

b=

44.690(2.068) + 26.196(0.430)∙n–O– R2 = 0.99892

SD = 1.7980

P <0.0001 (12)

Ac

Qo = –7.527(1.391)+ 7.766 (0.268)∙n–O–

where: n–O– is the number of oxygen atoms in the glymes molecules; R2 is the regression coefficient, SD is the standard deviation and P is the probability that regression coefficient is equal to zero. Such a relationship is not observe in the case of cyclic ethers [38]. Probably this is due to stiffening the ring cyclic ethers, especially 1,4-dioxane, 12C4. The molecules of 18C6 are

6 Page 6 of 29

more susceptible to changes in conformation. The chains of glymes molecules are flexible and therefore can be easier incorporated into the structure of the mixed solvent. We performed also the analysis of the effect of structural and energetic properties of mixed solvents on the standard solution enthalpy of glymes. As we proposed in our previous paper, the structural properties of the mixtures are expressed by the excess volume (VE), while the energetic properties of the mixture are presented by excess enthalpy (HE) [13,38]. The

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structure of mixed solvent depends on the composition of mixture (type of components and their proportion) and on the type and energy of interactions between the mixture components.

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To describe the structural and energetic properties of mixed solvent, one can use the excess molar volume, VE, and the excess molar enthalpy, HE, as a function of mixture composition. It

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is assumed that VE is a measure of the structural properties of mixture, while HE is mainly a measure of energetic properties but also structural properties since a change in the structure

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brings about changes in the energetic properties. Both functions describe the deviations of properties of the given mixture from those of an ideal mixture. Thus, the dissolution of the

structure of the mixture.

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compound results in the process of solvation, which significantly depends on the existing

In order to perform this analysis we calculated the deviation from the additivity of the standard

ed

solution enthalpy of glymes using Eq. (13).

 solH E (DMF Y)   solH o (DMF Y)  [(1  xDMF ) solH o (Y)  xDMF  solH o (DMF)]

(13)

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where:  solH E (DMF Y) is the deviation from additivity of the standard solution enthalpy of glymes in the mixtures of Y (MeOH or W) with DMF, solH o (DMF Y) ,  solH o (Y),  solH o (DMF)are the standard solution enthalpy of glymes in the mixtures of Y (MeOH or

Ac

W) with DMF, in pure solvent Y and in pure DMF, respectively, xDMF is the mole fraction of DMF in the mixture DMF+Y. Then we described the values of  solH E (DMF Y) obtained as a linear combination of the VE and HE of the mixed solvent (DMF+Y) (Eq. (14)). solH E (DMF Y)  cV E  dH E

(14)

where VE and HE are the excess molar volume and excess molar enthalpy of the mixtures DMF+MeOH or DMF+W, respectively. The factors cVE and dHE illustrate the contributions of the mentioned earlier properties (i.e. structural and energetic) of the mixed solvent to the 7 Page 7 of 29

total variation of  solH E (DMF Y) . The values of VE and HE for DMF+MeOH and DMF+W mixtures were taken form literature [33,39–41]. The parameters of Eq. (14) calculated are presented in Table 6 for DMF+MeOH mixtures and in Table 7 for DMF+W mixtures. As is seen, the regression coefficients are high and standard deviations are small. The contributions of the structural and energetic properties of

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DMF+MeOH mixtures to the function solH E (DMF MeOH)= f(xMeOH) are positive. While, in the mixtures DMF+W the contributions of both structural and energetic properties of

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mixture to the function solH E (DMF W) = f(xw) are negative, except monoglyme, where the contribution of the structural properties is positive. Moreover, in the case of diglyme and

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triglyme, the contribution of structural properties to the function solH E (DMF W) = f(xw) is not observed. The difference observed in the contribution of the structural and energetic

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properties to the function solH E (DMF Y) = f(xy) in mixtures DMF+MeOH and DMF+W is undoubtedly due to the hydrophobic hydration of glymes in DMF+W mixtures.

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Furthermore, it turned out that the parameters c and d of Eq. (14) depend linearly on the number of oxygen atoms in the glymes molecule (Eqs. (15–18)). DMF+MeOH

R2 = 0.99639 SD = 0.0096

P < 0.0001

(15)

d = 0.510(0.209) + 0.587(0.040) n–O–

R2 = 0.98618 SD = 0.1269

P = 6.910–4

(16)

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DMF+W

ed

c = –0.066(0.016) + 0.088(0.002) n–O–

c = 3.206(0.527) – 1.063(0.099) n–O–

R2 = 0.98303 SD = 0.3697

P = 0.0085

(17)

d = –4.886(0.471) – 1.477(0.097) n–O–

R2 = 0.98272 SD = 0.4096

P = 1.110–4

(18)

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Using the parameter values shoved in Tables 6 and 7, the deviation from the additivity of the standard solution enthalpy of glymes in DMF+MeOH and DMF+W mixtures were calculated and presented as a function of xMeOH or xw on Figs. 4 and 5 together with the same function calculated form experimental values. As is seen, the agreement between both the functions calculated is very good. Figs 6 and 7 show graphical illustration of Eq. (14). As seen, the contribution of the energetic properties of both mixtures i.e. DMF+MeOH and DMF+W are much higher then the structural properties. Such regularity was not observed in the case of cyclic ethers [38]. According to our opinion this is due to the rigidity of the cyclic ethers ring, and thus the difficulty in building up the existing structure of the mixed solvent. We can say that in this case the macrocyclic effect is clearly observed. 8 Page 8 of 29

Although the contributions of structural properties (cVE) and energetic properties (dHE) to solH E (DMF W) (Fig. 7) are much higher than in solH E (DMF MeOH) (Fig. 6) but it is

possible to observe a similar increase in structural and energetic properties with an increase in the chain length of glymes. This is particularly evident in the case of the participation of energetic properties. In DMF+W mixtures this is due to the hydrophobic hydration of glymes.

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This fact confirms the relationship dHE in maximum as a function of enthalpic effect of hydrophobic hydration of glymes (Hb(W)) [12,17] (Eq. 19)).

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E dH max  6.922(1.146)  0.378(0.022) Hb(W) R2 = 0.98631 SD = 0.8081 P < 0.0001 (19)

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In the case of cyclic ethers the dependence of cVE in maximum on the enthalpic effect of hydrophobic hydration of cyclic ethers is observed [38]. As seen also in this case the macrocyclic effect is observed.

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Based on the analysis made, it can be stated that the replacement of methanol with water in the mixture with DMF exerts a great effect on the standard solution enthalpy of glymes as

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well as on the contribution of structural properties.

Conclusions

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1. The replacement of methanol with water in the mixture with DMF significantly changes the shape of the solHo= f(x) function of glymes as well as the contribution of acid-base and

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structural-energetic properties of mixed solvents to the standard solution enthalpy values. 2. The standard solution enthalpies of glymes correlate with the base properties of DMF+MeOH mixtures, while in DMF+W mixtures depends on both acid and base properties.

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3. The deviation from the additivity of the standard solution enthalpy of glymes depends on the structural and energetic properties of DMF+MeOH and DMF+W mixtures. 4. The macrocyclic effect on the contribution of the acid-base and structural-energetic properties of DMF+MeOH and DMF+W mixtures to the standard solution enthalpy is observed.

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[22] M. Jóźwiak, Thermochemical behaviour of crown ethers in the mixtures of water with organic solvents. Part IX. Effect of base-acid properties of {(1 – x)AN + xH2O} on the solution enthalpy of cyclic ethers in this mixed solvent at T = 298.15 K, J. Chem. Thermodyn. 41 (2009) 522–524.

Ac

[23] M. Jóźwiak, The effect of carbonyl carbon atom replacement in acetone molecule (ACN) by sulphur atom (DMSO) Part III. Effect of base-acid properties of the mixtures of water with acetone or dimethylsulfoxide on the solution enthalpy of cyclic ethers in mixed solvent, J. Therm. Anal. Calorim. 101 (2010) 1039–1045. [24] J.A. Riddick, W.B. Bunger, T.K. Sakano, Organic Solvent, vol. II (1986) p. 869. [25] J.A. Riddick, W.B. Bunger, T.K. Sakano, Organic Solvent, vol. II (1986) p. 1089. [26] H. Piekarski, D. Waliszewski, Hydration effect on urea-non-electrolyte enthalpic pair interaction coefficients. Dissolution enthalpies of urea in aqueous solution of alkoxyethanols at 298.15 K, Thermochim. Acta 258 (1995) 67–76.

11 Page 11 of 29

[27] R. Sabbah, A. Xu-wu, J.S. Chickos, M.L. Planas Leitão, M.V. Roux, L.A. Torres, Reference materials for calorimetry and differential thermal analysis, Thermochim. Acta, 331 (1999) 93–204. [28] I. Wadsö, R.N. Goldberg, Standards in isothermal microcalorimetry (IUPAC Technical Report), Pure Appl. Chem. 73 (2001) 1625–1639. [29] M. Jóźwiak, L. Madej-Kiełbik, Effect of temperature on the process of complex

from (293.15 to 308.15)K, Thermochim. Acta 580 (2014) 13–19.

ip t

formation crown ether 15C5 with Na+ in the (water+ethanol) mixture at temperatures

cr

[30] V.P. Barannikov, S.S. Guseynov, A.I. Vyugin, Enthalpies of solution of ethylene oxide oligomers CH3O(CH2CH2O)nCH3 (n =1 to 4) in different H-bonding solvents: methanol,

us

chloroform, and water. Group contribution method as applied to the polar oligomers. J. Chem. Thermodyn. 43 (2011) 1928–1935.

an

[31] M. A. Villamanan, C. Casanova, A.H. Roux, J.P.E. Grolier, Calorimetric investigation of the interactions between oxygen and hydroxyl groups in alcohol + ether at 298.15 K. J. Chem. Thermodyn. 14 (1982) 251–258.

M

[32] A. Wakisaka, S. Komatsu, Y. Usui, Solute-solvent and solvent-solvent interactions evaluated through clusters isolated from solutions: Preferential solvation in water-

[33]

A.M.

Zaichikov,

ed

alcohol mixtures, J. Mol. Liq. 90 (2001) 175–184. G.A.

Krestov

Thermodynamic

properties

of

water-N,N-

dimethylformamide system. (in russ.). Zh Fiz Khim. 69 (1995) 389–394.

ce pt

[34] T.M. Krygowski, Ch. Reichardt, P.K. Wrona, C. Wyszomirska, U. Zielkowska, Empirycal parameters of Lewis basicity of binary solvent mixtures. Mixtures with methanol, J. Chem. Research (S) 1983, 116–117. [35] M.E. Mancini, A. Terenzani, M.G. Gasparri, L.R. Votterc, Determination of the

Ac

empirical polarity parameter ET(30) for binary solvent mixtures, J. Phys. Org. Chem. 8 (1995) 617–623.

[36] Ch. Reichardt, E. Harbusch-Görnert, Über Pyridinium-N-phenolat-Betaine und ihre Verwendung zur Charakterisierung der Polarität von Lösungsmitteln, X, Liebigs Ann. Chem. (1983) 721–896. [37] T.M. Krygowski, W.R. Fawcett, Complementary Lewis acid-base description of solvent effects. I. Ion-ion and ion-dipole interactions, J. Am. Chem. Soc. 97 (1975) 2143–2148. [38] M. Jóźwiak, H. Piekarski, A. Bińkowska, K. Łudzik, Effect of properties of the N,Ndimethylformamide+methanol and N,N-dimethylformamide+water mixtures on the

12 Page 12 of 29

solution enthalpy of cyclic ethers in these mixtures at 298.15 K, J. Therm. Anal. Cal. DOI: 10.1007/s10973-016-5664-7, in press. [39] C. Wang, H. Li, L. Zhu, S. Han, NMR and excess volumes studies in DMF-alcohol mixtures. J. Solution Chem. 31 (2002) 109–117. [40] C. de Visser, D. Perron, J.E. Desnoyers, W.J.M. Heuvelsland, G. Somsen, Volumes and

Eng. Data 22 (1977) 74–79.

ip t

heat capacities of mixtures of N,N-dimethylformamide and water at 298.15 K. J. Chem.

[41] H. Iloukhani, H.A. Zarei, Excess molar enthalpies of N,N-dimethylformamide + alkan-1-

Ac

ce pt

ed

M

an

us

cr

ols (C1-C6) at 298.15 K. J. Chem. Eng. Data 47 (2002) 195–197.

13 Page 13 of 29

Table 1 Materials Chemical Name

Source

Urea

Fluka

Mass fraction purity >0.995a

Purification Method

Mass fraction of water [ppm]

recrystallization from ethanol and dried under

−

ip t

vacuum to constant mass

>0.995a

dried under vacuum to

Aldrich

anhydrous

constant mass

diethylene glycol

Sigma-

>0.995a

dimethyl ether

Aldrich

us

cr

Sigma-

KCl

triethylene glycol

Aldrich

>0.99a

Aldrich

>0.99a

dimethyl ether

tetra(ethylene

M

(triglyme)

an

(diglyme)

glycol) dimethyl

ed

ether (tetraglyme) was prepared

glycol dimethyl

as described

ether (pentaglyme)

in papers [12]

hexaethylene

was prepared

>0.99b

ce pt

pentaethylene

as described

ether (hexaglyme)

in papers [17]

MeOH

Chempur

Ac

glycol dimethyl

−

2000c

700c

1000c

3000c

3000c

>0.99b

>0.998a

Methanol was dried by

800c

means of magnesium activated with iodine and distilled at 337,7 K [24]

DMF

Aldrich

0.998a

DMF was dried over type

200c

4A molecular sieves and fractionally distilled over reduced pressure [25] a

Declared by the supplier.

14 Page 14 of 29

b

The purity of the compound has been determined by means of 1H NMR (see Supplementary Material).

ce pt

ed

M

an

us

cr

ip t

Determined by Karl Fisher method.

Ac

c

15 Page 15 of 29

ip t cr

Table 2

diglyme

–0.94 ± 0.08 –1.55 ± 0.07 –2.04 ± 0.05 –2.64 ± 0.05 b b b –0.90 ± 0.03 [12] –1.55 ± 0.08 [12] –1.98 ± 0.04 [12] –2.64 ± 0.04 [12]b –0.87 ± 0.07

–1.41 ± 0.06

0.20

–0.78 ± 0.07

–1.24 ± 0.07

0.30

–0.66 ± 0.08

–1.04 ± 0.07

0.40

–0.51 ± 0.08

0.50

–0.31 ± 0.08

0.60

0c –0.06d

–2.84 ± 0.04

–1.58 ± 0.06

–2.04 ± 0.05

–2.46 ± 0.05

–1.29 ± 0.06

–1.69 ± 0.06

–2.03 ± 0.05

–0.79 ± 0.08

–0.92 ± 0.07

–1.23 ± 0.06

–1.50 ± 0.06

–0.46 ± 0.08

–0.48 ± 0.07

–0.69 ± 0.08

–0.87 ± 0.06

0c –0.07d

0c –0.14d

ce

0.22 ± 0.07

0.80 0.90

–3.19 ± 0.05 –3.18 ± 0.04 [17]b

–2.35 ± 0.05

0c –0.07d

0c 0.03d

0.35 ± 0.07

0.60 ± 0.08

0.60 ± 0.08

0.66 ± 0.08

0.51 ± 0.07

0.79 ± 0.06

1.19 ± 0.06

1.32 ± 0.07

1.49 ± 0.07

0.80 ± 0.06

1.25 ± 0.06

1.79 ± 0.06

2.05 ± 0.05

2.34 ± 0.06

1.10 ± 0.06 0.86 ± 0.02 [30]

1.71 ± 0.05 1.20 ± 0.02 [30]

2.40 ± 0.05 1.67 ± 0.03 [30]

2.79 ± 0.05

3.21 ± 0.05

Ac

0.70

hexaglyme

–1.81 ± 0.05

d

0.10

1

pentaglyme

an

tetraglyme

pt e

0

triglyme

M

xMeOH

solH o [kJ/mol]

a

us

Standard solution enthalpy of glymes in DMF+MeOH mixtures at 298.15 K at the pressure p = 0.1 MPa.

0.51± 0.01e 16 Page 16 of 29

ip t cr

xMeOH is the mole fraction of MeOH in the mixtures with DMF.

± are the expanded uncertainties, U, at the 0.95 level of confidence.

us

a

Standard uncertainties u are: u(xDMF) = 0.01, u(T) = 0.01 K, u(p) = 10 kPa.

The values of standard enthalpy of solution were obtained by us and presented in our previous papers.

c

The heat effects of solution of glymes in this mixture were not measurable.

d

the value estimated from the function solH o = f(xMeOH).

e

Data calculated form the excess enthalpy [31].

Ac

ce

pt e

d

M

an

b

17 Page 17 of 29

Table 3 Parameters of Eq. (1) for the standard solvation enthalpy of glymes in DMF, MeOH and W at 298.15 K. solvent

a

b

n–O–

R2

SD

P

–7.50±0.98

–14.28±0.20

2÷7

0.99920

0.8480

<0.0001

MeOH

–7.41±1.16

–13.40±0.22

3÷7

0.99916

0.7077

<0.0001

–16.02±1.39

–21.25±0.29

2÷7

0.99926

0.7623

<0.0001

W

R is the regression coefficient.

us

P is the probability that regression coefficient is equal to zero.

cr

± is the standard deviation.

ip t

DMF

Table 4

an

Values of parameters of Eq. (6): the value of the given property in the absence of the solvent effect (Qo,), the contribution of the base properties (b) to the variation of the standard enthalpy

M

of solution ( solH o ) of glymes in DMF+MeOH mixtures at 298.15 K. b

R2

SD

P

15.04± 0.54

−22.33 ± 0.80

0.98860

0.0796

<0.0001

triglyme

23.77 ± 0.81

−35.38 ± 1.19

0.99000

0.1182

<0.0001

tetraglyme

32.32 ± 1.09

−47.94± 1.60

0.99002

0.1597

<0.0001

pentaglyme

39.26 ± 1.32

−58.42 ± 1.94

0.99014

0.1935

<0.0001

hexaglyme

0.99028

0.2260

<0.0001

46.13 ± 1.54

ed

diglyme

ce pt

Qo

−68.73 ± 2.27

± is the standard deviation.

R is the regression coefficient.

Ac

P is the probability that regression coefficient is equal to zero.

18 Page 18 of 29

Table 5 Values of parameters of Eq. (7): the value of the given property in the absence of the solvent effect (Qo,), the contribution of the acid properties (a), the contribution of the base properties (b), of DMF+W to the variation of the standard enthalpy of solution ( solH o ) of glymes in DMF+W mixtures at 298.15 K. Qo

a

R2

b

46.67 ± 0.58

95.96±0.62

diglyme

−112.42 ± 0.50

58.62 ± 0.77

122.86±0.83

triglyme

−139.23 ± 0.55

71.53 ± 0.85

152.25±0.91

tetraglyme

−157.73 ± 0.67

77.32± 1.03

174.61±1.11

0.97896

pentaglyme

−184.52 ± 0.79

92.27± 1.23

202.92±1.32

0.97707

hexaglyme

−204.87 ± 0.90

99.60± 1.39

226.83±1.49

0.97779

ip t

−87.90 ± 0.38

0.97415 0.97729 0.97942

cr

us

monoglyme

an

± is the standard deviation assuming constancy of the other parameters.

M

R is the regression coefficient.

Table 6

Values of parameters of Eq. (14): for glymes in DMF+MeOH mixtures at 298.15 K.

0.19± 0.04

triglyme

0.30 ± 0.05

tetraglyme pentaglyme hexaglyme

R2

2.15 ± 0.13

0.99294

2.92± 0.17

0.99373

ce pt

diglyme

d

ed

c

0.36 ± 0.06

3.59± 0.22

0.99314

0.47 ± 0.07

4.03 ± 0.25

0.99371

0.55 ± 0.08

4.53 ± 0.29

0.99337

Ac

± is the standard deviation.

R is the regression coefficient.

19 Page 19 of 29

Table 7 R2

monoglyme

0.92± 0.41

−7.55 ± 0.21

0.99918

diglyme

−

−9.13 ± 0.06

0.99886

triglyme

−

−11.47 ± 0.08

0.99852

tetraglyme

−1.67 ± 0.39

−12.44 ± 0.20

0.99979

pentaglyme

−3.25 ± 0.71

−13.59 ± 0.37

0.99946

hexaglyme

−4.45 ± 0.63

−15.02 ± 0.33

0.99967

± is the standard deviation.

Ac

ce pt

ed

M

an

us

R is the regression coefficient.

cr

d

c

ip t

Values of parameters of Eq. (14): for glymes in DMF+W mixtures at 298.15 K.

20 Page 20 of 29

4

ip t

3

cr

1

us

solH0/kJ mol-1

2

0

an

-1

M

-2

0.2

ce pt

-4 0.0

ed

-3

0.4

0.6

0.8

1.0

xMeOH

Fig. 1. Standard solution enthalpies of glymes: diglyme, ; triglyme, ; tetraglyme, ;

Ac

pentaglyme, ; hexaglyme, , in DMF+MeOH mixtures at 298.15 K.

21 Page 21 of 29

10

ip t

0

cr us

-20

-30

an

trH/kJ mol

-1

-10

M

-40

-60

0.2

ce pt

0.0

ed

-50

0.4

0.6

0.8

1.0

xMeOH, xw

Fig. 2. Transfer enthalpies of glymes from DMF to DMF+MeOH mixtures: diglyme, ;

Ac

triglyme, ; tetraglyme, ; pentaglyme, ; hexaglyme, , from DMF to DMF+W mixtures (calculated using the data from literature): monoglyme,  [12]; diglyme, □ [12]; triglyme,  [12]; tetraglyme,  [12]; pentaglyme,  [12]; hexaglyme,  [17], at 298.15 K.

22 Page 22 of 29

1.0

ip t

0.9

cr

0.8

us

0.6

N

ET , BKT

0.7

an

0.5

M

0.4

0.2

0.2

ce pt

0.0

ed

0.3

0.4

0.6

0.8

1.0

xMeOH, xw

Ac

Fig. 3. Acid ()–base () properties of DMF+MeOH mixtures at 298.15 K (see the text) and acid ()–base (□) properties of DMF+W mixtures at 298.15 K [14].

23 Page 23 of 29

cr

ip t

0.0

us

-0.4

an

solHE/kJ mol-1

-0.2

ed

ce pt

-0.8

M

-0.6

0.2

0.4

0.6

0.8

1.0

xMeOH

Ac

-1.0 0.0

Fig. 4. Deviation from the additivity of the standard enthalpy of solution of glymes in DMF+MeOH mixtures at 298.15 K as a function of xMeOH: diglyme, ; triglyme, ; tetraglyme, ; pentaglyme, and hexaglyme,. The solid lines are fits to the experimental data and the dashed lines were calculated using Eq. (14).

24 Page 24 of 29

cr

ip t

40

us an

20

M

solHE/kJ mol-1

30

ce pt

0

ed

10

0.2

0.4

0.6

0.8

1.0

xw

Ac

0.0

Fig. 5. Deviation from the additivity of the standard enthalpy of solution of glymes in DMF+W mixtures at 298.15 K as a function of xw: monoglyme, ; diglyme, ; triglyme, ; tetraglyme, ; pentaglyme,  and hexaglyme,◄. The solid lines are fits to the experimental data and the dashed lines were calculated using Eq. (14).

25 Page 25 of 29

ip t cr -0.2

-0.2

-0.4 -0.5

-0.4 -0.5 -0.6

d

-0.6

-0.3

-0.2

M

-0.3

-0.8 -0.9

0.2

0.4

0.6

0.8

-0.4 -0.5 -0.6 -0.7

-0.8

-0.8

-0.9

-0.9

-1.0 0.0

0.2

0.4

0.6

xMeOH

0.8

1.0

-1.0 0.0

0.2

0.4

0.6

0.8

1.0

xMeOH

ce

xMeOH

1.0

-0.3

-0.7

pt e

-0.7

tetraglyme -0.1

cVE, dHE, solHE/kJ mol-1

-0.1

0.0

triglyme

an

-0.1

-1.0 0.0

us

0.0

diglyme

cVE, dHE, solHE/kJ mol-1

cVE, dHE, solHE/kJ mol-1

0.0

Ac

Fig. 6. Graphical illustration of Eq. (14) for the deviation from additivity of the standard enthalpy of solution of glymes in DMF+MeOH mixture at 298.15 K: cV E , ; dH E , ;  sol H E , .

26 Page 26 of 29

ip t cr hexaglyme

-0.1

-0.3 -0.4

d

-0.5 -0.6 -0.7 -0.8

-0.6

-0.8

-0.9

0.2

0.4

0.6

Fig. 6. Continued.

1.0

-1.0 0.0

0.2

0.4

0.6

0.8

1.0

xMeOH

Ac

xMeOH

0.8

ce

-1.0 0.0

-0.4

M

cVE, dHE, solHE/kJ mol-1

-0.2

pt e

cVE, dHE, solHE/kJ mol-1

-0.2

us

0.0

pentaglyme

an

0.0

27 Page 27 of 29

ip t cr 30

30

20

15

10

5

0 0.2

0.4

0.6

0.8

1.0

35

30

25

20

15

10

5

5

0

0

0.0

0.2

0.4

0.6

xw

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

xw

ce

xw

pt e

10

0.0

20

d

15

25

M

25

triglyme

40

cVE, dHE, solHE/kJ mol-1

35

diglyme

an

35

cVE, dHE, solHE/kJ mol-1

cVE, dHE, solHE/kJ mol-1

40

us

monoglyme

40

Ac

Fig. 7. Graphical illustration of Eq. (14) for the deviation from additivity of the standard molar enthalpy of glymes in DMF+W mixture at 298.15 K: cV E , ; dH E , ;  sol H E , .

28 Page 28 of 29

ip t cr 30

30

20

20

15

d

15

25

M

25

cVE, dHE, solHE/kJ mol-1

35

10

5

pt e

10

hexaglyme

40

pentaglyme

an

35

30

20

10

5

0 0.0

us

40

tetraglyme

cVE, dHE, solHE/kJ mol-1

cVE, dHE, solHE/kJ mol-1

40

0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

xw

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

xw

Fig. 7. Continued.

Ac

ce

xw

0

29 Page 29 of 29