Molecular interactions in the binary mixtures of some monoalkanolamines with acetonitrile between 303.15 and 323.15

Accepted Manuscript Molecular interactions in the binary mixtures of some monoalkanolamines with acetonitrile between 303.15 and 323.15

Muhammad A.R. Khan, M. Mehedi Hasan Rocky, Faisal Islam Chowdhury, M. Shamsuddin Ahmed, Shamim Akhtar PII: DOI: Reference:

S0167-7322(18)35857-4 https://doi.org/10.1016/j.molliq.2018.12.136 MOLLIQ 10212

To appear in:

Journal of Molecular Liquids

Received date: Revised date: Accepted date:

12 November 2018 24 December 2018 26 December 2018

Please cite this article as: Muhammad A.R. Khan, M. Mehedi Hasan Rocky, Faisal Islam Chowdhury, M. Shamsuddin Ahmed, Shamim Akhtar , Molecular interactions in the binary mixtures of some monoalkanolamines with acetonitrile between 303.15 and 323.15. Molliq (2018), https://doi.org/10.1016/j.molliq.2018.12.136

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ACCEPTED MANUSCRIPT Molecular Interactions in the Binary Mixtures of Some Monoalkanolamines with Acetonitrile between 303.15 and 323.15 Muhammad A. R. Khan, M. Mehedi Hasan Rocky1, Faisal Islam Chowdhury, M. Shamsuddin Ahmed and Shamim Akhtar*

for

correspondence.

E-mail:

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*Author

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Department of Chemistry, University of Chittagong, Chittagong-4331, Bangladesh

[email protected].

Tel.:

+8801712090205; Fax: +880 31726310. 1

Present address: Department of Natural Science, Port City International University,

Chittagong, Bangladesh.

[1]

ACCEPTED MANUSCRIPT ABSTRACT Densities,, and refractive indices, nD for the binary systems of acetonitrile (ACN) + monoethanolamine

(MEA),

+

monomethylethanolamine

(MMEA),

and

+

monoethylethanolamine (MEEA) have been measured in the whole range of composition and at different temperatures from T = (303.15 to 323.15) K for , and at T = 303.15 for nD. Excess molar volumes, VmE, partial molar volumes, Vi , thermal expansivities, , and excess thermal

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expansivities, E, were calculated from the experimental ρ. From measured nD at 303.15 K deviations in refractive index, nD, and excess molar refractions, RmE, for the mixtures have

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also been evaluated. Values of VmE, E, and RmE were found to be almost negative within the studied range of temperature. For each system the values of ρ, , and nD were correlated to

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appropriate polynomials, whereas those of VmE, E, nD, and RmE were fitted well to the Redlich-Kister type equations. Moreover, temperature dependent Jouyban-Acree model also

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showed satisfactory correlation with the experimental ρ values for all the systems. It has been suggested that, though intermolecular interactions of various types influence the variation

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patterns of VmE, Vi , E, and RmE vs. composition for these systems, those due to cross H-

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bonding and interstitial accommodation effect have to play the significant roles.

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Keywords: Density; refractive index; acetonitrile; alkanolamine; Jouyban-Acree model.

[2]

ACCEPTED MANUSCRIPT 1. Introduction CO2 as a potent greenhouse gas is acting as dominant factor to the current climate changes. Since the early foundation work [1] of Swede Svante Arrhenius, it has been a great concern for scientists in formulating some mathematical relation between the atmospheric CO2 and increment of global surface temperature. Use of CO2 as a reagent has also some positive ramifications. There is an increasing attempt to consider CO2 a resource, as it can be considered

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as an abundant and inexpensive carbon feedstock, especially if carbon sequestration is required for future fossil fuel-based power stations [2–4]. So, there is always significant interest in CO2

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capture and sequestration technologies applying chemical, thermochemical, photochemical, and electrochemical procedures [5].

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To abate CO2 concentration, research studies [6,7] have been performed abundantly for designing energy efficient absorption system through capturing CO2 in a more economical

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way. Chemical absorption of CO2 using amines and alkanolamines as solvents has been used in industries [8–10] since the development of purification process patented by Bottoms [11] in

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1930. Among alkanolamines, the monoethanolamine (MEA) is used widely for the removal of CO2 due to its some unique properties, such as, high reactivity, low solvent cost, low absorption of hydrocarbons, and its high capability for complete removal of acidic gases [12]. Again,

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blended solutions of amines and alkanolamines by mixing a physical solvent to another

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chemical solvent has received increasing attention due to some of the early successes as mentioned in different reports [6,7,13]. Also, use of nonaqueous solutions of alkanolamines

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causes an enhancement in the rate of absorption of CO2 [13]. Interestingly, it has been reported that acetonitrile can form stable complexes with CO2 [14], and therefore, any study considering acetonitrile as a cosolvent with alkanolamine may be quite judicious. As organic aprotic solvents can dissolve CO2 much more than water can do, many investigators [15–18] have studied the electrochemical reduction of CO2 in organic solvents using various metal electrodes capable to reduce CO2 at low overpotentials. Acetonitrile is often used in the electrochemical process [19] of CO2 conversion due to its high dielectric constant and potential window. But a proton source, like water, has to be added in order to obtain better products, like methane or methanol at low overpotentials. The presence of metalcomplexing agents in the supporting electrolyte, such as, ammonia or pyridine, enhances the efficiency of the electrochemical reduction [20]. Considering alkanolamines in place of water may thus yield better results as these compounds has high CO2 affinity [21,22].

[3]

ACCEPTED MANUSCRIPT As acetonitrile and alkanolamine are widely used for CO2 reduction/removal process separately, their blended mixtures (alkanolamine + acetonitrile) have a high chance to be found with great utility for CO2 processing either in chemical absorption methods or in electrochemical methods. Though study of alkanolamine + acetonitrile mixtures is not reported yet, such a system needs more attention at least from scientific point of view. In consideration of their industrial interests it is also important to investigate their physic-chemical properties,

intermolecular interactions. Many investigators

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and hence, to characterize mixture properties through understanding the relevant

have already reported [8,13,23–30] important physico-chemical monoethanolamine (MEA),

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properties for a number of pure alkanolamines, such as,

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diethanolamine (DEA), triethanolamine (TEA), monomethylethanolamine (MMEA), monoethylethanolamine (MEEA), dimethylethanolamine (DMEA), methyldiethanolamine

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(MDEA), ethyldiethanolamine (EDEA), diethylethanolamine (DEEA) etc. and also for their aqueous binary mixtures [31]. But reports on alkanolamines in non-aqueous media are scarcely available. Among the various non-aqueous solvents, acetonitrile (ACN) as a polar solvent is

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capable to dissolve a wide range of compounds without complication. It has become a popular choice for liquid chromatography due to its low viscosity and low chemical reactivity. An

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extensive survey has shown that no report is available yet for the systems consisting of ACN

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and the ethanolamine derivatives. As a part of our ongoing studies with the alkanolamines, therefore, here we have attempted to report mainly on densities and refractive indices for the binary mixtures of some monoalkanolamines, viz., MEA, MMEA, and MEEA with ACN over

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the entire range of concentration and at different temperatures between T = 303.15 and 323.15 K. Experimental data of ρ, and nD and some of their derived properties are used to fit with appropriate form of polynomials and their deviations/excess properties to the Redlich-Kister type [32] equations to obtain the model parameters. Experimental data of ρ can also be tested for the Jouyban-Acree model [33,34]. The relevant derived as well as excess properties for the binary mixtures would definitely lead to having a better insight into molecular interactions existing between ACN and the monoalkanolamines. So far we know, the systems under present investigation are yet to be reported.

[4]

ACCEPTED MANUSCRIPT 2. Experimental Section ACN (Aldrich, mass fraction > 0.995), MEA (Aldrich, mass fraction = 0.99), MMEA (Merch-Schuchardt, mass fraction > 0.98) and MEEA (Merch-Schuchardt, mass fraction > 0.97) were used without further purification, except that the alkanolamines were kept under molecular sieves for three weeks prior to use. Table 1 summarizes the chemical description of the pure liquids. The purity of the component liquids was further checked by comparing the

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measured densities with the available literature values as shown in Table 2. A set of 21 compositions for each system was prepared by mixing known masses of pure liquids, which

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were completely miscible over the whole composition range. The mass measurements were made by an electronic balance (SAG 285, Mettler Toledo) with an accuracy of ±10 -7 kg. To

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avoid evaporation/contamination, solutions were always kept in air-tight glass stopper bottles and handled carefully.

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Density (/kgm-3) were measured by means of an automated vibrating-tube density meter (DSA 5000M, Anton Paar, Austria) with an accuracy of ±0.01 kgm-3. As the values of ρ are

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extremely sensitive, temperature was controlled up to ±0.01 K by a built-in solid state thermostat. The manufacturer stated repeatability for ρ and T measurements were ±0.001 kgm3

and ±0.001 K, respectively. Refractive index, nD, was measured by using the Abbe

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Refractometer (Abbe 60/ED) and its temperature was maintained by an electronically

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controlled thermostatic water bath (Thermo Haake, UK). The Abbe Refractometer readings at the sodium D-line were converted into corresponding nD values. The uncertainty in measured

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nD was found to be ±0.0002. For all the pure components and mixtures, each time triplicate measurements were performed and always their mean was taken into consideration. 3. Results and discussion

The experimental values of the densities, , along with the calculated values of excess molar volumes, VmE, for the binary mixtures of ACN with MEA, or MMEA, or MEEA measured over the whole range of composition between 303.15 and 323.15 K are summarized in Table 3. Variations of  at different temperatures against x2 are graphically represented by Figs. 1(a-d). For the pure components observed  increase as: MEA > MMEA > MEEA > ACN, and  for the systems initially increases rapidly and then slowly at least in the highly alkanolamine-rich regions. Categorically, alkanolamines are presumed to be self- associated through H-bonding [30,31]. Therefore, other than the weak dispersion and dipole-dipole

[5]

ACCEPTED MANUSCRIPT interaction that exist within their mixtures the observed steep rise of  from x2 = 0.0 up to equimolar ratio (x2 = 0.5) can primarily be attributed as due to strong intermolecular hydrogen bonding between the component liquids. However, interaction can be at different extents for the systems. As Fig. 1(d) shows, at the solute-rich region the order of increment of  follows: ACN + MEA > ACN + MMEA > ACN + MEEA, which is also in the same order of increasing self-association tendency of the pure alkanolamines.

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Thermodynamically, excess molar volume,VmE, of any mixture measures the overall volume change due to mixing up of its components. The VmE values are calculated from

x M i

ρ

i



xi M i ρi

(1)

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VmE 

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experimental data of  by the following equation:

where Mi and i denote the molar mass and density of the i-th component and  as the density

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of the mixture at composition xi. At different temperatures variation of VmE against mole fraction x2 are represented by Fig. 2. For all systems, VmE values are large negative with well-

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defined minima at x2 ≈ 0.55, 0.65 and 0.35 for ACN + MEA, ACN + MEA and ACN + MEEA, respectively. The magnitude of VmE follows the order: ACN + MEA > ACN + MMEA > ACN + MEEA.

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For all systems large negative VmE values indicate that, as a whole, factors responsible

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for volume contraction far outweighed the factors causing volume expansion. In these particular systems of ACN + MEA, + MMEA and + EEA, negative VmE values arise obviously

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from specific interactions and any other effects whether they are due to physical, chemical or structural aspects are also thought to be strongly responsible for volume contraction. Considering size difference between acetonitrile and alkanolamines (MEA, MMEA, and MEEA) and their ability to form cross H-bonds, here also one of the factors primarily responsible for large volume contraction is suggested to be due to the same strong and specific interaction that leads to the formation of cross H-bonds (O‒H·····N) between the component liquids. In addition, forces due to dipole-dipole or dipole-quadrapole type. between the component molecules are also thought to be responsible for volume contraction of these systems. Besides that, any other factor that favours some geometrical fitting between the component liquids can also reinforce overall compactness. Here the consideration is as follows. As the monoalkanolamines are highly associated and the molecules of ACN are very small in size, the latter can be thought to incorporate or accommodate themselves within the cavities of structural networks MEA, MMEA as well as MEEA easily. This is known as interstitial accommodation effect, which

[6]

ACCEPTED MANUSCRIPT can also lead to further volume contraction. Not only is that, being trapped within cavities of alkanolamines, there also further possibility of cross H-bonding between the respective components inside. All these factors thus contribute further to VmE becoming more negative. They are also suggested to be responsible for shifting minima of the VmE vs. x2 curves towards the alkanolamine-rich region as in Fig. 2, which are in contradiction to the position of minima at the water-rich regions for the aqueous systems [31]. With the rise of temperature, the VmE

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values become more negative i,e., dVmE/dT are negative. The negative sign which indicates greater volume contraction at rising temperature, is also in agreement to that for the aqueous systems observed earlier. However, temperature effect on VmE for all systems is only significant

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at or around their compositions of minima.

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Literature reports on H-bond interactions [39,40] are also in agreement with our present investigation. Each of the alkanolamines and acetonitrile is highly capable to form H-bond due

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to their molecular organization: molecules of alkanolamines form H-bonds through their amino (–NH2) and hydroxyl (–OH) functional groups, whereas ACN can form such a bond intermolecularly by either with the lone-pair electrons of the N atom or with the C≡N triple

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bond. Various energetic effects and composition dependent properties are affected by H-bonds. Formation of molecular aggregates due to intermolecular H-bonding play an important role as

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in various earlier reports on phenol + acetonitrile [40], amine + acetonitrile [41], alkanolamines

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+ water [31,42] and acetonitrile + alcohol [43] type systems and all of their explanations for cross H-bonds are found to in agreement with our present investigation.

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Partial molar volume of a particular component, Vi , is a parameter which signifies the component’s actual volume contribution towards the molar volume of a solution. Here, Vi of the components 1 (ACN) and 2 (MEA or MMEA or MEEA) for the systems were calculated by following Maham et. al. [44] as:

n

n

i 0

i 0

V 1  V1  x22  Ai ( 2 x2  1 )i  2 x1 x22  iAi ( 2 x2  1 )i-1 n

V 2  V2  x12  Ai( 2 x2  1 )i  2 x12 x2 1  x2 

2

i 0

(2)

n

 iA ( 2 x i 0

i

2

 1 )i-1

(3)

where, V1 and V2 represent the partial molar volume of components 1 and 2 for a particular system and Ai is i-th fitting coefficient of the Redlich–Kister polynomial. The values of V1 and

V2 for all the systems are summarized in Table 4 and their variations against x2 are graphically [7]

ACCEPTED MANUSCRIPT represented by Figs. 3-4. As Figs. 3(a-c) show, V1 forms minima at alkanolamine –rich regions and they are nearly at x2 = 0.75 and 0.90 for ACN + MEA and ACN + MMEA, respectively. For the ACN + MEEA system decrement of V1 is even sharper beyond extremely higher concentration of MEEA. All these reveal that, for all systems contribution of ACN in reducing molar volumes of the mixtures is distinctively at the alkanolamine-rich regions, where the tiny ACN molecules could have been encapsulated within the hydrogen-bonded alkanolamine

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networks. Categorically this can therefore be attributed as due to the interstitial accommodation

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effect. On the other hand, as Fig. 4 shows, V2 for ACN + MEA are large at both ends and form minima at x2 = 0.50, whereas for the other two systems V2 values are quite large at the

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alkanolamine-rich regions, but their magnitudes drastically fall below x2 = 0.10. The behavior V2 thus indicated that the alkanolamines also contribute to the overall volume contraction; their

the ACN + MEA and ACN + MMEA systems.

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contribution might be due to cross H-bonding and likely being stronger in the ACN-rich region for

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Again, comparing the variation patterns of V1 and V2 [Figs. 3-4] with the respective VmE vs. x2 curves [Fig. 2] it is also clarified that, in reducing the overall molar volumes of the mixtures the contribution of the alkanolamines is relatively greater in the ACN-rich regions, whereas that

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of ACN is in the alkanolamine –rich regions. Nevertheless, as in Fig. 3(d) the negative VmE is to

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follow the order ACN + MEA > ACN + MMEA > ACN + MEEA and the position of minimum for ACN + MMEA lies at highly alkanolamine-rich region (x2 = 0.70). This further signifies that

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interstitial incorporation of ACN molecules is more in the structural networks of MMEA compared to those of MEA and MEEA. Thermal expansivity is considered as another important parameter in the understanding the type of molecular interactions. By definition, average isobaric thermal expansivity, α, of liquids can be expressed as:  d ln ρi  αi     dT  

(4)

So that, slope of the plot of ln ρ vs. T yields α. Excess thermal expansivity, E, of any mixture is then obtained by following the equation,

α E  α  x1α1  x2 α2 

(5)

Here, 1 and 2 are thermal expansivities of pure components 1 and 2, respectively and  is

[8]

ACCEPTED MANUSCRIPT that of the mixture. The concentration dependences of  and corresponding E values are as listed in Table 5. Fig. 5 compares the E as a function of x2 for the systems ACN + MEA, ACN + MMEA and ACN + MEEA. The values of E are negative for all systems except slightly positive E up to x2 = 0.05  0.20 for the ACN + MEA system. These lead to suggest that, initially there is slight destructurization which persists due to weakening in the selfassociation of ACN and alkanolamines at least for ACN + MEA, but significant structure

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making effect occurs for all the systems at higher concentrations. This is also in support of large negative VmE near the composition of minima for the three systems and all preferably at

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higher temperatures.

were calculated, by using the following relations:

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nD  nD  x1nD1  x2 nD2 

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From experimental values of refractive indices, nD, deviations in refractive index, ∆nD,

(6)

where, nD represents the refractive index of mixture and nD1 and nD2 are that of the pure

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components 1 and 2. All the terms having their usual significances, excess molar refractions, RmE, were also calculated from nD and VmE by following the relations: (7)

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 n2  1  E Vm RmE   2D  nD  2 

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where, all the terms having their usual significances. The values of nD, ∆nD, and RmE are listed in Table 6. Comparative diagrams for nD, ∆nD, and RmE are as shown in Figs. 6(a-c),

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respectively.

In general, refractive index indicates the compactness of a medium relative to vacuum. For binary mixtures, nD depends not only on the density of solute and solvent molecules, but also on the factors like molecular polarizability, steric effect, intermolecular interaction between the components etc. [33,45]. While some of the factors assist the light beams to pass through the medium, others can create obstacles too. In fact, the resultant refractive index of mixtures is influenced by all these factors. Therefore, considering steric hindrance, differences in polaraizability of the component molecules and also obstacles created due to interaction between the –OH group of the alkanolamines and N-atom of the ACN molecule, rhe value of nD is suggested to increase. As deviations have also to follow the same trend, the order of increasing nD is: ACN + MEA > ACN +MMEA > ACN + MEEA. Again, from Fig. 6(c) it is also noticeable that the values of RmE are almost negative and their variation against x2 shows a similar trend as the respective VmE variation [Fig. 2(d)]. In fact as it has been depicted in Eq. (7), the RmE is

[9]

ACCEPTED MANUSCRIPT 



found to differ from the VmE by a quotient nD2  1 nD2  2 , the magnitude of which is always less than unity. Therefore the observed resembling pattern of both the RmE vs. x2 and VmE vs. x2 curves are also found to hold good. In order to correlate each of , , and nD the polynomial equation of the following form is used: n

Y   ai x 2

i

(8)

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i 0

Here, Y represents ,  or nD , ai the i-th fitting coefficient and x2 is the mole fraction of the

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alkanolamines. Values of ai and their respective standard deviation, σ, at different temperatures

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have been computed and they are as summarized in Table 7. Each of the deviations/excess properties ΔY/YE (VmE,E, ∆nD, or RmE) of the mixtures was correlated by the nonlinear least-

m

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squares method and fitted to Redlich–Kister polynomials of the general form:

Y / Y E  x1 x2  Ai x2  x1 

i

(9)

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i 0

Here, Ai is the fitting coefficients and m is the degree of polynomial expansion optimized by using the F test [46,47]. The standard deviations, σ (YE), was calculated as:

 n  p

E 2 cal

Y

1 2

(10)

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   Y

E exp

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 Y

E

where, n represents the number of experimental data points and p is the number of coefficients. The values of coefficients Ai are listed in Table 8 along with their σ (YE).

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Jouyban et al. [34] has proposed a model (Jouyban-Acree model) for correlating the densities of liquid mixtures with that of its component liquids at various temperatures. The equation proposed is given by:



ln m,T  x1 ln 1,T  x2 ln 2,T  x1 x2  ji x1  x2  T i



(11)

where ρm,T, ρ1,T, and ρ2,T are densities of the mixture and of the components 1 and 2 at temperature T, respectively and ji is the model constant. The correlating ability of the JouybanAcree model was tested by calculating standard percentage deviation, σ(%) [33]as12

2  1   Yexp  Ycal      100  (12)  %   Yexp    n  p     Here, Ycal and Yexp refer to calculated and experimental η or ν; n represents the number of

data points and p is the number of coefficients taken. All of the coefficients of Eq. (12) were obtained by the non-linear regression analysis and the resulting σ(%) obtained are as summarized in Table 9. The estimated σ(%) values for the systems of ACN + MEA, ACN +

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ACCEPTED MANUSCRIPT MMEA and ACN + MEEA were found to be 0.21,0.15, and 0.17, respectively, all of which considered as within its satisfactory limit. 4. Conclusion Fundamental properties, such as, densities, , as well as refractive indices, nD, for the binary systems of ACN + MEA, ACN + MMEA, and ACN + MEEA were measured over the entire

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range of composition, 0 ≤ x2 ≤ 1, at different temperatures between 303.15 and 323.15 K. From measured data of ρ and nD , derived properties, such as, excess molar volumes VmE, partial , thermal expansivities, , excess thermal expansivities, E, deviations in

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molar volumes

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refractive index nD, and excess molar refractions RmE were calculated. Correlating each of ρ, , , and nD to the concentration-dependent polynomials and applying Redlich-Kister

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equations to VmE, E, nD and RmE, the revevant coefficients as well as the standard deviations, σ, were obtained. The Jouyban-Acree model was also correlated well for experimental ρ for all three systems.

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For pure alkanolamines the magnitude of  and order of its variation were presumed to be related directly to the strength of self-association (MEA > MMEA > MEEA), but inversely to

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the steric hindrance effect (MEEA > MMEA > MEA). The  for the binary mixtures of MEA,

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MMEA and MEEA with ACN initially rises fast and then slows down; their order of increment following: ACN + MEA > ACN + MMEA > ACN + MEEA. However, VmE were highly

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negative, and also the dVmE/dT for all systems, observed temperature effect on VmE being high near the composition of minima. These are all indicative of significant volume contraction, which has been attributed mainly as due to strong cross H-bonding between the alkanolamines and ACN and also due to the called interstitial accommodation effect. For all systems negative

E supported that, overall interaction between ACN and the alkanolamines were obviously of ‘structure making’ in type.

Again, positive ΔnD values for all the systems and its increasing order of ACN + MEA > ACN + MMEA ≈ ACN + MEEA further led to suggest that, intermolecular interaction were all strong and strong enough in the ACN + MEA system due to its stronger cross H-bonding tendency. On the other hand, RmE values were all negative and their variation pattern against x2 exactly resembled the respective VmE vs. x2 curves for all the systems. The variation order of negative RmE as: ACN + MEA > ACN > MMEA > ACN + MEEA, is also the same as that of VmE. And therefore, all are in support of overall volume contraction and in the same sequence due to

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ACCEPTED MANUSCRIPT strong intermolecular interactions between ACN and the monoalkanolamines under present investigation.

Acknowledgment The authors gratefully acknowledge the financial grants from the Ministry of Science, Information and Communication Technology, Government of the People’s Republic of

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Bangladesh as well as the from the Third World Academy of Science, Trieste, Italy.

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molecular orientation of alkanolamines through temperature and pressure variation: A mixed molecular dynamics and quantum mechanics study, Comput. Mater. Sci. 131 (2017) 239–249. doi:https://doi.org/10.1016/j.commatsci.2017.02.001.

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nucleophilic aromatic substitution reactions in non-polar aprotic solvent: Reactions of phenyl 2,4,6-trinitrophenyl ether with amines in benzene-acetonitrile mixtures, Tetrahedron. (2005). doi:10.1016/j.tet.2005.06.009.

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Comput. (2014). doi:10.1021/ct5002158.

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[16]

ACCEPTED MANUSCRIPT

Figure 1: Densities,  against mole fraction, x2 at 303.15 K (●), 308.15 K (▲), 313.15 K (♦), 318.15 K (∗) and 323.15 K (■) for the systems: (a) ACN (x1) + MEA (x2), (b) ACN (x1) + MMEA (x2), (c) ACN (x1) + MEEA (x2) and (d) Comparative diagram of  vs. x2 at 303.15 K for the systems: ACN + MEA (●), ACN + MMEA (▲), and ACN + MEEA (■). Solid lines represent the polynomial fittings.

PT

Figure 2: Excess molar volumes, VmE against mole fraction, x2 at 303.15 K (●), 308.15 K (▲),

SC

RI

313.15 K (♦), 318.15 K (∗), and 323.15 K (■) of the systems: (a) ACN (x1) + MEA (x2), (b) ACN (x1) + MMEA (x2), (c) ACN (x1) + MEEA (x2), and (d) comparative curves of VmE for ACN + MEA (●), ACN + MMEA (▲), and ACN + MEEA (■) systems at 303.15 K for different molar ratios. Solid lines represent the polynomial fittings.

NU

Figure 3: Partial molar volumes of component 1, V1 , against mole fraction, x2 for the systems of (a) ACN (x1) + MEA (x2), (b) ACN (x1) + MMEA (x2), and (c) ACN (x1) + MEEA (x2) systems at 303.15 K (●), 308.15 K (▲), 313.15 K (♦), 318.15 K (∗), and 323.15 K (■).

MA

Figure 4: Partial molar volumes of component 2, V2 ,against mole fraction, x2 for the systems: (a) ACN (x1) + MEA (x2), (b) ACN (x1) + MMEA (x2), and (c) ACN (x1) + MEEA (x2) systems at 303.15 K (●), 308.15 K (▲), 313.15 K (♦), 318.15 K (∗), and 323.15 K (■).

AC CE P

TE

D

Fig. 5. Comparative diagrams of (a) thermal expansivities, α, and (b) excess thermal expansivities, αE, for the systems of ACN + MEA(●), + MMEA(▲) and + MEEA(■) against mole fraction, x2 at 303.15 K. Solid lines represent fittings for: (a) polynomial and (b) RedlichKister equations. Figure 6: Comparative diagrams for (a) refractive indices, nD, (b) deviation in refractive indices, ΔnD and (c) excess molar refractions, RmE of + MEA(●), ACN + MMEA(▲) and ACN + MEEA (■) systems against mole fraction, x2 at 303.15 K. Solid lines represent fittings with: (a) polynomial, (b) and (c) Redlich-Kister equations.

[17]

ACCEPTED MANUSCRIPT

Table 1: Specifications of the pure liquids

monoethanolamine (MEA) monomethylethanolamine (MMEA ) monoethylethanolamine

C2H3N

Aldrich

75-05-8

C2H7NO

Aldrich

141-43-5

C3H9NO

Merck

109-83-1

C4H11NO

Merck

110-73-6

formula

AC CE P

TE

D

MA

NU

(MEEA)

CAS no

initial purity

molar mass

(mass fraction)%

(g·mol-1)

>99.5

41.0519

PT

(ACN)

source

>99

RI

acetonitrile

molecular

SC

liquids

[18]

61.0831

>98

75.1097

>97

89.1362

ACCEPTED MANUSCRIPT Table 2: Densities, ρ, of the pure ACN, MEA, MMEA, and MEEA at different temperatures along with available data from different literatures compound

10–3/(kgm-3)

T/K exptl.

ACN

308.15

1.00483

1.0041[8], 1.004024 [13]

313.15

1.00091

1.0004[8],1.000370[11], 1.000037 [13], 1.00247[25]

318.15

0.99690

0.9960[8], 0.996029 [13]

323.15

0.99283

0.9927[8], 0.992364[11], 0.992014 [13], 0.99480[25]

303.15

0.93433

0.9323[30], 0.933789[35], 0.93402[7]

308.15

0.93028

0.9283[30], 0.929880[35]

313.15

0.92640

0.9243[30], 0.925948[35]

318.15

0.92261

0.9204[30], 0.921996[35]

323.15

0.91854

0.9165[30], 0.918024[35]

303.15

0.90901

0.90982[7], 0.9091[30] 0.909401[35]

308.15

0.90457

0.9049[30], 0.905405[35]

313.15

0.90057

0.9008[30], 0.901388[35]

318.15

0.89660

0.8968[30], 0.897344[35]

323.15

0.89254

0.8926[30], 0.893275[35]

303.15

0.77110

0.771487[36], 0.77121 [37], 0.77152[38]

308.15

0.76573

313.15

0.76042

0.760541[36], 0.7609[38]

318.15

0.75470

0.755014[36], 0.75559[38]

323.15

0.74927

0.749449[36]

MA

NU

SC

RI

PT

1.0081[8], 1.008323[11], 1.008002 [13], 1.00970[25]

D

MEEA

1.00921

0.766031[36], 0.76575[37], 0.76621[38]

TE

MMEA

303.15

AC CE P

MEA

lit.

[19]

ACCEPTED MANUSCRIPT Table 3. Densities, 10–3/(kgm-3) and Excess Molar Volumes, VmE·106/(m3·mol-1) of ACN + MEA, + MMEA and + MEEA Systems for Different Molar Ratios at Different Temperatures ρ VmE ρ VmE ρ VmE ρ VmE ρ VmE x2 303.15 K 308.15 K 313.15 K 318.15 K 323.15 K

0.3005 0.3509 0.3999 0.4516 0.4990 0.5504 0.5998 0.6490 0.6990 0.7498 0.8008 0.8501 0.8999 0.9499 1.0000

0.0000 0.0491

0.771 1 0.786 3

0.000

0.000 0.232

0.765 7 0.780 7

0.210 0.671 1.257 1.833 2.352 2.774 3.100 3.274 3.317 3.214 2.976 2.610 2.135 1.592 1.057 0.574 0.234 0.000

ACN + MMEA 0.760 0.000 0.000 4 0.774 0.219 8 0.173

[20]

0.150 0.120

PT

0.119

0.000

0.219 0.691 1.290 1.877 2.406 2.834 3.166 3.343 3.388 3.285 3.045 2.675 2.195 1.645 1.101 0.606 0.249

RI

0.146

0.754 7 0.768 2 0.776 7 0.797 1 0.817 0 0.839 9 0.862 4 0.883 8 0.903 4 0.922 0 0.936 9 0.950 4 0.960 7 0.968 4 0.973 9 0.977 6 0.980 0 0.982 1 0.985 0 0.990 1 0.996 9

SC

0.2492

0.000

NU

0.1959

0.172 0.617 1.184 1.740 2.239 2.643 2.953 3.116 3.154 3.052 2.822 2.471 2.019 1.504 0.997 0.539 0.211

MA

0.1465

0.139

D

0.0877

0.157

ACN+MEA 0.760 0.000 4 0.773 0.143 9 0.782 0.117 3 0.802 0.202 6 0.822 0.651 3 0.845 1.224 1 0.867 1.788 4 0.888 2.297 7 0.908 2.711 1 0.926 3.032 6 0.941 3.205 4 0.954 3.249 8 0.964 3.150 9 0.972 2.918 5 0.977 2.560 9 0.981 2.094 5 0.983 1.562 8 0.985 1.037 8 0.988 0.563 8 0.994 0.229 0 1.000 0.000 9

TE

0.0576

0.000

0.765 7 0.779 2 0.787 5 0.807 7 0.827 3 0.849 9 0.872 0 0.893 1 0.912 4 0.930 8 0.945 5 0.958 8 0.969 0 0.976 5 0.981 9 0.985 4 0.987 8 0.989 8 0.992 8 0.998 0 1.004 8

AC CE P

0.0000

0.771 1 0.784 3 0.792 5 0.812 5 0.832 1 0.854 7 0.876 8 0.897 8 0.916 9 0.935 1 0.949 6 0.962 7 0.972 7 0.980 2 0.985 6 0.989 2 0.991 7 0.993 9 0.997 0 1.002 2 1.009 2

0.754 7 0.769 6

0.000

0.000 0.206

0.749 3 0.762 8 0.771 3 0.791 8 0.811 9 0.835 0 0.857 6 0.879 3 0.899 0 0.917 8 0.932 9 0.946 5 0.956 9 0.964 6 0.970 1 0.973 7 0.976 1 0.978 1 0.981 0 0.986 0 0.992 8

0.749 3 0.764 3

0.000 0.154 0.122 -0.227 -0.712 -1.327 -1.928 -2.470 -2.909 -3.247 -3.429 -3.475 -3.370 -3.125 -2.747 -2.256 -1.693 -1.135 -0.625 -0.254 0.000

0.000 -0.213

ACCEPTED MANUSCRIPT

0.5003 0.5496 0.5994 0.6500 0.7001 0.7498 0.7998 0.8500 0.9000 0.9435 1.0000

0.0000 0.0499 0.1000 0.1500 0.1997 0.2498 0.2998

0.771 1 0.792 4 0.810 3 0.825 3 0.837 9 0.848 6 0.857 5

0.000

0.000 0.638 1.120 1.482 1.737 1.901 1.988

0.765 7 0.786 6 0.804 6 0.820 0 0.832 8 0.843 6 0.852 6

0.000

0.000

ACN + MEEA 0.760 0.000 0.000 4 0.781 0.612 8 0.654 0.799 1.107 9 1.153 0.815 1.488 2 1.526 0.828 1.761 0 1.790 0.838 1.936 8 1.961 0.847 2.025 9 2.053

[21]

0.451 0.740 1.015 1.277 1.523 1.755 1.939 2.086 2.206 2.290 2.343 2.358 2.329 2.244 2.084 1.819 1.416 0.918

PT

0.4492

0.784 5 0.799 9 0.814 0 0.827 3 0.840 1 0.853 1 0.864 3 0.874 4 0.884 1 0.892 7 0.900 7 0.907 9 0.914 3 0.919 7 0.923 9 0.926 7 0.927 7 0.926 8 0.922 6

RI

0.4001

0.410 0.701 0.984 1.254 1.508 1.746 1.931 2.078 2.194 2.273 2.320 2.331 2.300 2.215 2.057 1.798 1.403 0.912

SC

0.3498

0.789 5 0.804 9 0.819 0 0.832 4 0.845 3 0.858 2 0.869 4 0.879 4 0.889 0 0.897 4 0.905 2 0.912 3 0.918 5 0.923 8 0.927 9 0.930 7 0.931 7 0.930 7 0.926 4

NU

0.2964

0.476 0.764 1.031 1.280 1.511 1.728 1.897 2.032 2.141 2.217 2.263 2.275 2.245 2.160 2.004 1.747 1.359 0.879

MA

0.2469

0.795 7 0.811 0 0.824 9 0.837 9 0.850 5 0.863 0 0.873 9 0.883 7 0.893 1 0.901 5 0.909 2 0.916 2 0.922 4 0.927 5 0.931 6 0.934 3 0.935 3 0.934 4 0.930 3

D

0.1987

0.488 0.776 1.041 1.287 1.512 1.722 1.884 2.012 2.113 2.184 2.226 2.236 2.207 2.127 1.976 1.727 1.347 0.875

TE

0.1500

0.801 2 0.816 5 0.830 3 0.843 3 0.855 7 0.868 1 0.878 8 0.888 5 0.897 7 0.905 9 0.913 5 0.920 5 0.926 6 0.931 7 0.935 8 0.938 5 0.939 4 0.938 5 0.934 3

AC CE P

0.0983

0.754 7 0.776 2 0.794 4 0.809 9 0.822 9 0.833 9 0.843 1

0.000

0.000 0.662 1.167 1.555 1.830 2.008 2.102

0.779 3 0.794 9 0.809 0 0.822 3 0.835 2 0.848 2 0.859 4 0.869 6 0.879 4 0.888 1 0.896 2 0.903 6 0.910 2 0.915 7 0.920 1 0.923 0 0.924 0 0.923 0 0.918 5

0.749 3 0.770 8 0.789 1 0.804 7 0.817 8 0.828 9 0.838 2

-0.467 -0.762 -1.040 -1.302 -1.548 -1.779 -1.962 -2.110 -2.231 -2.319 -2.376 -2.399 -2.377 -2.300 -2.144 -1.879 -1.470 -0.956 0.000

0.000 -0.666 -1.183 -1.575 -1.854 -2.035 -2.130

ACCEPTED MANUSCRIPT

0.6001 0.6463 0.7000 0.7494 0.7995 0.8475 0.8957 0.9500 1.0000

0.000

0.855 6 0.862 0 0.867 6 0.872 4 0.876 9 0.880 9 0.884 3 0.887 9 0.891 0 0.893 9 0.896 3 0.898 3 0.899 9 0.900 6

0.000

2.078 2.050 1.981 1.884 1.761 1.627 1.497 1.339 1.188 1.022 0.845 0.637 0.346

0.850 9 0.857 4 0.863 0 0.867 9 0.872 4 0.876 4 0.879 9 0.883 6 0.886 8 0.889 7 0.892 3 0.894 3 0.896 0 0.896 6

0.000

2.127 2.094 2.018 1.918 1.785 1.645 1.518 1.357 1.207 1.038 0.873 0.657 0.366

PT

0.5500

2.040 1.997 1.910 1.796 1.659 1.520 1.393 1.250 1.123 0.988 0.843 0.659 0.375

RI

0.4986

0.860 1 0.866 3 0.871 6 0.876 2 0.880 5 0.884 3 0.887 7 0.891 4 0.894 7 0.897 8 0.900 5 0.902 6 0.904 2 0.904 6

SC

0.4495

2.007 1.976 1.904 1.805 1.679 1.545 1.414 1.259 1.111 0.952 0.786 0.591 0.321

NU

0.3997

0.865 0 0.871 3 0.876 7 0.881 4 0.885 7 0.889 5 0.892 8 0.896 3 0.899 3 0.902 1 0.904 5 0.906 6 0.908 2 0.909 0

MA

0.3501

0.000

0.846 1 0.852 6 0.858 3 0.863 2 0.867 8 0.871 8 0.875 3 0.879 2 0.882 5 0.885 6 0.888 2 0.890 3 0.892 0 0.892 5

-2.152 -2.118 -2.038 -1.930 -1.797 -1.656 -1.523 -1.366 -1.220 -1.061 -0.891 -0.684 -0.380 0.000

AC CE P

TE

D

Standard uncertainties (u): u(mole fraction, xi) = ±1×10-4, u(T) = ±0.01 K, u(mass) = ±1×10-7 s kg, u(calibration) = ±2×10-2 kg∙m-3, u(triplicate ρ value) = = 2×10-4 kg∙m-3; Expanded 3 -3 uncertainty at 95% confidence level: U(ρ) = ±0.11 kg∙m ; Error propagation, δ(VmE) = ±5.7×10-6%.

[22]

ACCEPTED MANUSCRIPT

Table 4. Partial Molar Volumes of ACN, V1 ·106/(m3·mol-1), and Partial Molar Volumes of MEA, MMEA, and MEEA, V 2 ·106/(m3·mol-1), in ACN + MEA, + MMEA, and +MEEA Systems respectively for Different Molar Ratios at Different Temperatures V1

V2

V1

V2

0.0491 0.0983 0.1500 0.1987 0.2469 0.2964 0.3498 0.4001 0.4492 0.5003 0.5496 0.5994 0.6500 0.7001 0.7498 0.7998 0.8500 0.9000 0.9435

53.114 52.821 52.430 52.046 51.690 51.364 51.058 50.798 50.549 50.271 49.964 49.605 49.192 48.754 48.329 47.970 47.758 47.792 48.107

63.741 65.704 67.759 69.616 71.329 72.920 74.422 75.623 76.601 77.430 78.072 78.588 79.006 79.342 79.619 79.857 80.062 80.229 80.333

53.489 53.199 52.809 52.422 52.057 51.716 51.389 51.109 50.841 50.550 50.238 49.881 49.475 49.049 48.637 48.292 48.103 48.184 48.586

ACN + MMEA 64.045 53.855 63.689 66.008 53.549 65.760 68.053 53.143 67.923 69.895 52.747 69.872 71.591 52.379 71.659 73.168 52.040 73.310 74.660 51.714 74.858 75.860 51.429 76.089 76.844 51.146 77.084 77.686 50.824 77.924 78.344 50.467 78.571 78.877 50.053 79.092 79.311 49.588 79.517 79.658 49.116 79.863 79.944 48.693 80.159 80.188 48.400 80.424 80.397 48.361 80.663 80.568 48.729 80.867 80.678 49.523 81.002

AC CE P

V1

V2

323.15 K

54.520 54.642 54.856 54.909 54.742 54.302 53.574 52.586 51.278 49.902 48.321 46.852 45.604 44.756 44.559 45.286 47.103 50.263 54.936

59.183 59.091 58.757 58.382 57.941 57.528 57.175 56.915 56.760 56.748 56.890 57.183 57.618 58.186 58.851 59.555 60.203 60.755 61.133

54.920 55.046 55.262 55.311 55.134 54.679 53.933 52.924 51.590 50.186 48.570 47.064 45.781 44.904 44.693 45.431 47.294 50.537 55.334

59.412 59.298 58.920 58.518 58.061 57.644 57.294 57.040 56.893 56.888 57.037 57.337 57.782 58.360 59.040 59.760 60.426 60.993 61.381

54.267 53.963 53.553 53.148 52.766 52.411 52.071 51.776 51.492 51.177 50.839 50.455 50.029 49.599 49.210 48.926 48.840 49.060 49.595

63.990 66.031 68.163 70.089 71.864 73.513 75.070 76.317 77.335 78.201 78.875 79.422 79.871 80.236 80.543 80.810 81.041 81.229 81.347

54.651 54.328 53.895 53.470 53.075 52.713 52.374 52.087 51.817 51.521 51.201 50.832 50.415 49.982 49.577 49.262 49.134 49.313 49.827

63.531 65.688 67.942 69.977 71.850 73.588 75.226 76.537 77.605 78.512 79.214 79.780 80.238 80.607 80.912 81.174 81.401 81.588 81.706

PT

53.736 53.857 54.074 54.133 53.979 53.556 52.850 51.889 50.618 49.283 47.754 46.341 45.151 44.357 44.199 44.933 46.706 49.741 54.173

RI

59.057 58.906 58.481 58.060 57.598 57.181 56.828 56.561 56.388 56.346 56.445 56.689 57.074 57.593 58.217 58.885 59.507 60.036 60.395

V2

318.15 K

SC

53.364 53.485 53.695 53.751 53.603 53.202 52.531 51.614 50.389 49.088 47.582 46.170 44.964 44.141 43.955 44.677 46.465 49.546 54.037

TE

0.0576 0.0877 0.1465 0.1959 0.2492 0.3005 0.3509 0.3999 0.4516 0.4990 0.5504 0.5998 0.6490 0.6990 0.7498 0.8008 0.8501 0.8999 0.9499

313.15 K ACN + MEA 59.047 54.112 59.235 58.941 54.235 59.130 58.583 54.456 58.770 58.186 54.517 58.371 57.721 54.361 57.902 57.284 53.933 57.462 56.909 53.216 57.083 56.629 52.240 56.800 56.456 50.947 56.624 56.430 49.585 56.596 56.559 48.024 56.724 56.840 46.577 57.007 57.264 45.355 57.434 57.817 44.532 57.994 58.465 44.355 58.652 59.147 45.089 59.346 59.772 46.890 59.984 60.300 49.990 60.524 60.658 54.541 60.892

V1

308.15 K

NU

V2

303.15 K

MA

V1

D

x2

ACN + MEEA 0.0499 53.198 91.590 53.547 90.604 53.942 91.985 54.345 91.997 54.733 92.030 0.1000 53.114 92.395 53.416 91.686 53.851 92.854 54.241 92.943 54.617 93.042 0.1500 53.021 93.218 53.282 92.797 53.746 93.737 54.127 93.907 54.491 94.079

[23]

ACCEPTED MANUSCRIPT 93.872 94.881 95.777 96.548 97.170 97.658 98.013 98.268 98.422 98.500 98.537 98.542 98.536 98.530 98.531 98.539

53.655 53.587 53.543 53.508 53.463 53.377 53.222 52.948 52.535 51.997 51.145 50.111 48.778 47.185 45.216 42.447

94.598 95.418 96.165 96.827 97.384 97.844 98.206 98.495 98.701 98.835 98.938 98.993 99.020 99.024 99.013 98.993

54.032 53.967 53.932 53.913 53.884 53.812 53.665 53.389 52.961 52.395 51.494 50.403 49.008 47.367 45.381 42.672

NU MA D TE [24]

94.844 95.732 96.536 97.242 97.829 98.308 98.678 98.966 99.165 99.289 99.378 99.423 99.443 99.446 99.439 99.427

PT

53.184 53.137 53.139 53.172 53.202 53.189 53.091 52.848 52.426 51.842 50.893 49.746 48.307 46.676 44.810 42.479

RI

94.025 94.796 95.498 96.118 96.637 97.062 97.391 97.651 97.833 97.950 98.038 98.085 98.107 98.109 98.097 98.075

SC

52.942 52.887 52.857 52.836 52.802 52.726 52.578 52.309 51.902 51.370 50.530 49.517 48.214 46.661 44.739 42.020

AC CE P

0.1997 0.2498 0.2998 0.3501 0.3997 0.4495 0.4986 0.5500 0.6001 0.6463 0.7000 0.7494 0.7995 0.8475 0.8957 0.9500

54.388 54.324 54.297 54.291 54.279 54.223 54.088 53.815 53.380 52.798 51.869 50.746 49.316 47.646 45.641 42.929

95.088 96.044 96.906 97.659 98.279 98.779 99.158 99.448 99.641 99.758 99.839 99.876 99.892 99.893 99.888 99.878

ACCEPTED MANUSCRIPT Table 5. Thermal Expansivities, α·104/ K-1, and Excess Thermal Expansivities, αE·104/ K1, of ACN + MEA, + MMEA and + MEEA Systems for Different Molar Ratios

PT

ACN + MEEA x2 α αE 0.0000 14.389 0.000 0.0499 13.707 -0.418 0.1000 13.119 -0.740 0.1500 12.577 -1.016 0.1997 12.109 -1.221 0.2498 11.689 -1.375 0.2998 11.333 -1.466 0.3501 11.004 -1.528 0.3997 10.723 -1.546 0.4495 10.475 -1.530 0.4986 10.239 -1.505 0.5500 10.025 -1.447 0.6001 9.8320 -1.373 0.6463 9.6517 -1.309 0.7000 9.4854 -1.190 0.7494 9.3371 -1.076 0.7995 9.2302 -0.917 0.8475 9.1193 -0.774 0.8957 9.0736 -0.564 0.9500 9.0414 -0.308 1.0000 9.0839 0.000

MA

NU

SC

RI

ACN + MMEA x2 α αE 0.0000 14.389 0.000 0.0491 14.205 0.107 0.0983 13.914 0.106 0.1500 13.511 0.009 0.1987 13.073 -0.141 0.2469 12.614 -0.314 0.2964 12.132 -0.504 0.3498 11.617 -0.703 0.4001 11.147 -0.875 0.4492 10.709 -1.022 0.5003 10.277 -1.152 0.5496 9.8884 -1.250 0.5994 9.5310 -1.312 0.6500 9.1927 -1.351 0.7001 8.8987 -1.349 0.7498 8.6483 -1.305 0.7998 8.4473 -1.211 0.8500 8.3124 -1.049 0.9000 8.2563 -0.809 0.9435 8.2904 -0.517 1.0000 8.4735 0.000

D

αE 0.000 -0.078 -0.209 -0.515 -0.811 -1.148 -1.468 -1.760 -2.006 -2.210 -2.336 -2.396 -2.372 -2.265 -2.071 -1.795 -1.452 -1.080 -0.698 -0.357 0.000

TE

ACN + MEA α 14.389 13.951 13.632 12.957 12.353 11.682 11.041 10.433 9.8800 9.3523 8.9296 8.5478 8.2631 8.0626 7.9433 7.9011 7.9252 7.9886 8.0582 8.0869 8.1301

AC CE P

x2 0.0000 0.0576 0.0877 0.1465 0.1959 0.2492 0.3005 0.3509 0.3999 0.4516 0.4990 0.5504 0.5998 0.6490 0.6990 0.7498 0.8008 0.8501 0.8999 0.9499 1.0000

[25]

ACCEPTED MANUSCRIPT Table 6. Refractive Index, nD, and Deviation in Refractive Index, ∆nD, and Excess Molar Refraction, RmE, of ACN + MEA, + MMEA and + MEEA Systems for Different Molar Ratios at 303.15 K RmE 0.000 -0.050 -0.107 -0.174 -0.238 -0.300 -0.357 -0.413 -0.457 -0.494 -0.524 -0.547 -0.562 -0.569 -0.565 -0.548 -0.511 -0.448 -0.351 -0.228 0.000

x2 0.0000 0.0499 0.1000 0.1500 0.1997 0.2498 0.2998 0.3501 0.3997 0.4495 0.4986 0.5500 0.6001 0.6463 0.7000 0.7494 0.7995 0.8475 0.8957 0.9500 1.0000

ACN + nD 1.3390 1.3509 1.3608 1.3696 1.3774 1.3845 1.3908 1.3965 1.4015 1.4061 1.4101 1.4140 1.4173 1.4202 1.4232 1.4257 1.4280 1.4300 1.4318 1.4336 1.4350

PT

MMEA ΔnD 0.0000 0.0056 0.0103 0.0143 0.0173 0.0197 0.0215 0.0230 0.0238 0.0241 0.0242 0.0237 0.0230 0.0218 0.0202 0.0182 0.0157 0.0128 0.0092 0.0056 0.0000

RI

ACN + nD 1.3390 1.3493 1.3586 1.3676 1.3752 1.3822 1.3887 1.3952 1.4008 1.4058 1.4107 1.4149 1.4189 1.4225 1.4257 1.4284 1.4307 1.4325 1.4337 1.4342 1.4340

SC

0.000 0.035 0.031 -0.041 -0.149 -0.293 -0.439 -0.572 -0.682 -0.767 -0.814 -0.827 -0.803 -0.743 -0.652 -0.533 -0.398 -0.264 -0.143 -0.056 0.000

x2 0.0000 0.0491 0.0983 0.1500 0.1987 0.2469 0.2964 0.3498 0.4001 0.4492 0.5003 0.5496 0.5994 0.6500 0.7001 0.7498 0.7998 0.8500 0.9000 0.9435 1.0000

NU

RmE

MA

ACN + MEA nD ΔnD 1.3390 0.0000 1.3600 0.0147 1.3704 0.0217 1.3878 0.0327 1.3998 0.0392 1.4103 0.0439 1.4183 0.0463 1.4246 0.0470 1.4293 0.0463 1.4330 0.0443 1.4355 0.0416 1.4375 0.0379 1.4388 0.0338 1.4398 0.0294 1.4405 0.0246 1.4413 0.0198 1.4421 0.0150 1.4432 0.0107 1.4446 0.0066 1.4465 0.0030 1.4490 0.0000

D

x2 0.0000 0.0576 0.0877 0.1465 0.1959 0.2492 0.3005 0.3509 0.3999 0.4516 0.499 0.5504 0.5998 0.649 0.699 0.7498 0.8008 0.8501 0.8999 0.9499 1.0000

MEEA ΔnD 0.0000 0.0071 0.0122 0.0162 0.0192 0.0215 0.0230 0.0239 0.0241 0.0239 0.0232 0.0222 0.0207 0.0192 0.0170 0.0148 0.0122 0.0096 0.0068 0.0034 0.0000

RmE 0.000 -0.138 -0.248 -0.335 -0.400 -0.445 -0.472 -0.483 -0.481 -0.468 -0.447 -0.420 -0.389 -0.358 -0.321 -0.285 -0.245 -0.203 -0.153 -0.083 0.000

AC CE P

TE

Standard uncertainties (u): u(mole fraction, xi) = ±1×10-4, u(T) = ±0.05 K, u(mass) = ±1×10-7 s kg, u(calibration) = 0.0002, u(triplicate nD value) = = 0.0002; Expanded uncertainty at 3 95% confidence level: U(nD) = 0.1000; λ of refractometer: 589 nm (Sodium D-line). Error propagation, δ(ΔnD) = ±1.45×10-5%.

[26]

ACCEPTED MANUSCRIPT Table 7. Coefficients, ai, of Eq. 8, expressing Densities, ρ, Thermal Expansivities, α, Refractive Index, nD, and Standard Deviation, , of ACN + MEA, + MMEA and + MEEA Systems for Different Molar Ratios at Different Temperatures a2

a3

a4

σ

0.091 0.087 0.087 0.090 0.089

1.462 1.485 1.500 1.498 1.514

-2.461 -2.487 -2.512 -2.506 -2.531

1.142 1.150 1.163 1.158 1.168

0.0001 0.0002 0.0002 0.0002 0.0002

-9.374

3.693

6.185

-0.992

0.012

1.339

0.411

-0.566

0.267

0.0003

-0.038 -0.045 -0.050 -0.055 -0.057

0.0006 0.0005 0.0005 0.0005 0.0006

1.053

2.860

0.002

-0.121

0.019

0.0003

0.461 0.479 0.465 0.473 0.478

-0.760 -0.820 -0.760 -0.776 -0.791

0.679 0.757 0.680 0.696 0.716

-0.242 -0.275 -0.244 -0.250 -0.259

0.00003 0.0002 0.00002 0.00007 0.00009

-6.007

-1.752

-2.082

0.599

0.302

0.006

1.341

0.217

-0.189

0.067

property

T(K)

a0

ρ·103/ (kg·m-3)

303.15 308.15 313.15 318.15 323.15

0.775 0.770 0.765 0.759 0.753

a1

303.15

ACN + MMEA

nD

303.15

-4.608

4.500

-0.115 -0.107 -0.103 -0.093 -0.090

SC

0.322 0.321 0.325 0.321 0.321

NU

α·104/ (K-1)

0.771 0.765 0.759 0.754 0.749

MA

ρ·103/ (kg·m-3)

303.15 308.15 313.15 318.15 323.15

1.340

RI

α·104/ (K-1) nD

PT

ACN + MEA

0.197

TE

α·104/ (K-1) nD

0.771 0.764 0.760 0.754 0.749

AC CE P

ρ·103/ (kg·m-3)

303.15 308.15 313.15 318.15 323.15

303.15

D

ACN + MEEA

[27]

0.0002

ACCEPTED MANUSCRIPT

Table 8: Coefficients, Ai, of Eq. 9, expressing Excess Molar Volumes, VmE, Excess Thermal Expansivities, αE, Deviation in Refractive index, nD, Excess Molar Refraction, RmE, and Standard Deviation,  of ACN + MEA, + MMEA and + MEEA Systems for Different Molar Ratios at Different Temperatures A0

VmE·106/ (m3.mol-1)

303.15 308.15 313.15 318.15 323.15

-12.51 -12.87 -13.15 -13.42 -13.76

A1 A2 ACN + MEA 4.330 16.23 4.632 16.48 4.645 16.79 4.743 16.87 4.865 17.17

0.167

0.132

0.009

303.15

0.1702

-0.1339

303.15

-3.268

1.306

VmE·106/ (m3.mol-1) αE·104/ (K-1) ∆nD RmE·106/ (m3·mol-1)

0.161 -0.288 -0.182 -0.008 0.017

-1.090 -1.277 -1.253 -1.113 -0.991

0.013 0.014 0.014 0.014 0.014

-0.0004

0.00003

4.437

-0.225

-8.448 -8.561 -8.771 -8.818 -8.918

ACN + MMEA 3.432 -2.803 3.677 -2.626 3.876 -2.112 4.067 -2.496 4.159 -2.945

3.850 3.728 4.616 4.010 4.277

0.002 0.001 0.001 0.002 0.002

-4.608

4.500

1.053

2.860

0.002

0.0196

-0.0004

0.00002

-0.712

0.961

0.001

-7.194 -7.167 -7.514 -7.644 -7.699

ACN + MEEA -4.503 -3.406 -5.066 -3.964 -4.416 -3.574 -4.687 -3.730 -4.849 -3.959

1.080 2.850 1.081 1.571 1.934

0.004 0.001 0.003 0.004 0.003

-6.007

-1.752

-2.082

0.599

303.15

0.093

0.034

0.017

0.008

0.0001

303.15

-1.785

-0.969

-0.646

0.434

0.0005

303.15

0.0965

303.15

-2.095

303.15 308.15 313.15 318.15 323.15

NU

MA

303.15 308.15 313.15 318.15 323.15

SC

0.0198

AC CE P

αE·104/ (K-1) ∆nD RmE·106/ (m3·mol-1)

σ

0.0002

D

VmE·106/ (m3·mol-1)

A4

-0.015

-0.0090

TE

αE·104/ (K-1) ∆nD RmE·106/ (m3·mol-1)

A3

PT

T(K)

RI

property

1.060

[28]

-0.666

0.302

0.004

0.006

ACCEPTED MANUSCRIPT Table 9. Coefficients, ji, of the Jouyban-Acree Model and Standard Percentage Deviation, (%) for Densities, (10–3/kgm-3) j0

j1

j2

J3

σ(%)

ACN + MEA

95.45

-18.74

-92.20

-3.449

0.21

ACN + MMEA

71.95

-2.536

7.873

-18.65

0.15

ACN + MEEA

66.30

39.71

27.33

2.972

0.17

NU

SC

RI

PT

system

MA

Highlights

 Reports on density and refractive index for alkanolamines + acetonitrile systems.

D

 Excess molar volume and excess molar refraction values were negative.

TE

 Redlich-Kister equation used to fit excess properties.

AC CE P

 Cross H-bonding between acetonitrile and alkanolamines played significant roles.  Temperature dependent Jouyban-Acree model tested within good limit.

[29]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6