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Osmotic properties of carbohydrate aqueous solutions
Accepted Manuscript Osmotic Properties of Carbohydrate Aqueous Solutions Nosaibah Ebrahimi, Rahmat Sadeghi PII:
S0378-3812(16)30088-7
DOI:
10.1016/j.fluid.2016.02.030
Reference:
FLUID 11019
To appear in:
Fluid Phase Equilibria
Received Date: 8 January 2016 Revised Date:
14 February 2016
Accepted Date: 17 February 2016
Please cite this article as: N. Ebrahimi, R. Sadeghi, Osmotic Properties of Carbohydrate Aqueous Solutions, Fluid Phase Equilibria (2016), doi: 10.1016/j.fluid.2016.02.030. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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ACCEPTED MANUSCRIPT Osmotic Properties of Carbohydrate Aqueous Solutions
Nosaibah Ebrahimi, Rahmat Sadeghi∗
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Department of Chemistry, University of Kurdistan, Sanandaj, Iran
Abstract
Precise systematic osmotic coefficient measurements have been carried out for aqueous solutions of
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different carbohydrates and polyols by using vapor pressure osmometry (VPO) method. Herein, in order to investigate the effect of structure and stereochemistry of solutes on the vapor-liquid
solutions
containing
pentose
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equilibria behavior of aqueous solutions, we studied the osmotic properties of binary aqueous sugar monosaccharides
(xylose,
ribose
and
arabinose),
hexose
monosaccharides (glucose, fructose, galactose and mannose), disaccharides (sucrose, maltose and lactose), trisaccharide (raffinose) and polyols (sorbitol, xylitol and maltitol) at 308.15 K and in the
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extended concentration range. From the experimental osmotic coefficient data, the values of water activity and vapor pressure of the investigated solutions were obtained.
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Solutions
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Keywords: Vapor pressure osmometry; Osmotic coefficient; Activity; Carbohydrate; Aqueous
∗
Corresponding author. Tel.: +98 87 33624133; fax: +98 87 33660075. E-mail address: [email protected] and [email protected]
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ACCEPTED MANUSCRIPT 1. Introduction Carbohydrates which are a large natural resource have long interested chemists and biochemists because of their predominant role in biological and industrial applications. An important fraction of carbohydrates is made up of the smaller building units, namely sugar monomers and oligomers, and
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their aqueous solutions are mainly associated with the processing and the preservation of foods [1]. Thermodynamics investigations of aqueous carbohydrates solutions will be helpful in the precise design of operations and equipment used in food industries including chemical feed stocks, food
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production, and preservation of processed foods as well as in the study of the reaction conditions (e.g. feasibility and optimization) of currently employed industrial processes such as enzymatic
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conversion of biomass to useful chemicals [2]. As an example, water activity of solutions can be controlled by freeze drying and evaporation processes in order to reduce microorganism's growth and osmotic pressure caused by high concentrations of sugars that also inhibit food contaminations [3]. Although, a systematic and extensive study of water activities could contribute to a better
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understanding of the sugars hydration mode, which is a topic of considerable importance, a comprehensive understanding in this respect is yet to emerge. In the present work, for the first time, systematic vapor pressure osmometry (VPO) measurements
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have been carried out for several binary aqueous sugar solutions containing pentose monosaccharides, hexose monosaccharides, disaccharides, trisaccharide and polyols, at 308.15 K
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and in the extended concentration range in order to comprehensive study of vapor-liquid equilibrium of these systems and precise determine water activity and osmotic coefficients of them. Although previously water activity and osmotic coefficient data have been reported in the literatures for some aqueous carbohydrate solutions from isopiestic [4-12], hygrometry [13-15], freezing point depression [16, 17] and manometry [18, 19] methods, but these techniques aren’t precise as VPO, the number of data reported in the dilute concentration region is limited, none of them is an extensive study, and besides those data have often been reported at 298.15 K (except water activity obtained from the freezing point depression method which is the activity at the corresponding
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ACCEPTED MANUSCRIPT freezing point temperature and may be had considerable difference with water activity at room temperature (298.15 K) or human body temperature (310.15 K)).
2. Experimental Section
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2.1. Materials The properties of the chemicals used in this work have been listed in Table 1 and their structures have been presented in Scheme 1. Given that in aqueous solutions pyranose conformation of the
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investigated monosaccharides is more favored than furanose conformation, in scheme 1 only pyranose form have been drawn for all the monosaccharides. The chemicals were used without
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further purification and double distilled and deionized water was used.
2.2. Methods
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All the solutions were prepared by mass on a Sartorius CP124S balance precise to within ±1·10-7 kg. The VPO measurements were performed using an Osmomat K-7000 (Knauer Inc.) at 308.15 K. The cell temperature was controlled electronically within ±1·10-3 K. The instrument consists of two
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thermistors (1 and 2) placed in an airtight cell (its gas phase is saturated by solvent vapor) which measure resistance changes caused by changes in temperature. Initially, a droplet of pure water is
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attached to both thermistors with the help of a microsyringe, and after equilibration (∼5 min), the reading is adjusted to zero. After that, the pure water on thermistor 1 is replaced by the carbohydrate solution. Because of the condensation of water from the vapor phase into the carbohydrate solution, the thermistor 1 will be warmed and vapor pressure rises. This condensation process continues until the vapor pressure of the carbohydrate solution equals to the vapor pressure of pure water. In this steady state (a time of 4–8 min suffices to reach it), the thermistors measure the resistance differences (R) due to the change of temperature (T) between the two thermistors. T is proportional to R, when T is small. Initially, the instrument was calibrated using aqueous
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ACCEPTED MANUSCRIPT NaCl solutions as reference and from which a correlation between the panel readings and the corresponding concentrations of the NaCl solutions (and therefore their osmotic coefficients) was obtained. After that, the measurements for the different aqueous carbohydrates solutions were carried out in the same conditions. In this work, we performed experiments with three different
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modes of instrument setting, hence the instrument was calibrated with aqueous NaCl solutions at three conditions: (bridge voltage = 100 %, gain = 16), (bridge voltage = 52.1 %, gain = 16) and (bridge voltage = 100 % and gain = 1) for dilute, middle and concentrated regions, respectively. The
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following relation was used to correlate instrument panel reading (signal, SI) and NaCl molality
m NaCl = b0 + b1SI + b2 SI 2 + b3SI 3
(1)
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(mNaCl):
where b0, b1, b2 and b3 are calibration constants and their values are reported in Table 2. The osmotic coefficient, Φ, of a carbohydrate solution with molality m which has a same instrument reading as a sodium chloride solution with molality mNaCl, was obtained according to:
ν NaCl m NaCl Φ NaCl m
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Φ=
(2)
where ν NaCl is the stoichiometric number of NaCl. ΦNaCl is the osmotic coefficient for aqueous
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solutions of NaCl with molality mNaCl calculated from the correlation of Colin et al.[20] The
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uncertainty in the measurement of osmotic coefficient was found to be better than ± 1·10-3.
3. Result and Discussion
The osmotic coefficients of the systems investigated at 308.15 K are given in Table 3. From the experimental osmotic coefficient data, the values of water activity and vapor pressure for the solutions were determined through the following equations [21]:
mM w Φ a w = exp − 1000
(3)
5
(
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)(
p B o − Vwo p − p wo ln a w = ln o + w RT pw
)
(4)
where Mw is the molecular weight of the solvent, Bwo is the second virial coefficient of water vapor, Vwo is the molar volume of liquid water, and p wo is the vapor pressure of pure water. The value of
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Bwo at 308.15 K equals -1016.75 cm3.mol-1, where calculated using the equation provided by Rard
and Platford [22]. The obtained water activities and vapor pressures data of the systems investigated at 308.15 K are also given in Table 3.
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Figure 1 shows the experimental osmotic coefficients and water activities for monosaccharides: D-
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xylose, D-ribose, L-arabinose, D-mannose, D-fructose, D-galactose and D-glucose. As can be seen, the values of the osmotic coefficients follow the order: (D-Glucose ≥ D-galactose) > (D-fructose ≥ L-arabinose) > (D-xylose ≥ D-mannose) > D-ribose. Although the differences between the values of the water activities (and also vapor pressures) are very small, close examination of Figure 1b
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indicates the reverse order to that observed for the osmotic coefficients. As can be seen, except for D-mannose, water activities of aqueous solutions of hexose monosaccharides are smaller than that of pentose monosaccharides. This is because the hexose monosaccharides have more hydroxyl
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groups (hydrophilic group) in their structures than the pentose monosaccharides. The hydration of a
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carbohydrate is mostly dependent on the axial and equatorial arrangements of its hydroxyl groups. Equatorial hydroxyl substituents are more easily hydrated than axial. In Table 4, the arrangements of the hydroxyl groups substituent at C-2, C-3 and C-4 of the investigated pentose and hexose monosaccharides have been given (since fructose is a ketohexose monosaccharide, there are some differences between its structure and geometry with other investigated hexose monosaccharides which are aldohexose (see Scheme1), so in this table hydroxyl groups position of fructose have not been attended). The only difference between D-xylose and L-arabinose (and also between Dglucose and D-galactose) is that D-xylose (and D-glucose) has an equatorial OH(4), but L-arabinose (and D-galactose) has an axial OH(4). The smaller values of water activity for L-arabinose than D-
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ACCEPTED MANUSCRIPT xylose as well as the similar water activity values for D-glucose and D-galactose indicate that the arrangement of OH(4) doesn’t have a significant effect on the carbohydrate hydration. However, the smaller values of water activity for D-xylose than D-ribose as well as that for D-glucose than Dmannose indicate that the arrangements of OH(2) and OH(3) greatly affect the hydration of
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carbohydrates. The dynamic hydration numbers of hexose monosaccharides in aqueous solutions obtained from the natural-abundance oxygen-17 magnetic relaxation follow the trend: glucose > galactose > fructose > mannose [23] which is in agreement with the results obtained in this work. In
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fact, the equatorial OH groups are able to interact with water in a manner which forms a long-lived hydration structure, since equatorial OH groups on pyranose sugars match the unperturbed water
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lattice [24].
The experimental osmotic coefficients and water activities of the investigated aqueous disaccharides solutions are shown in Figure 2. It should be noted that in the case of lactose and raffinose because of low carbohydrate water solubility, osmotic properties measurements have been
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done just in the concentrations below 0.7 mol.kg-1. As can be seen, the values of the osmotic coefficients and water activities respectively follow the order: lactose > sucrose > maltose and lactose < sucrose < maltose. Type of two constituent monosaccharide units of a disaccharide and
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also the position and mode of linkage between monosaccharides affect the disaccharide hydrophilic degree. From the trend obtained for water activity of monosaccharide solutions, we expect the
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trend: maltose (consist of two glucose units) < lactose (consist of a glucose and a galactose units) < sucrose (consist of a glucose and a fructose units) for the water activity of the investigated disaccharide solutions. The observed unexpectedly larger values for water activity of aqueous maltose solutions may be aroused from that maltose can form an intramolecular hydrogen bond in water [25]. Similarly, Galema et al.[25] from the density and ultrasound measurements of aqueous disaccharide solutions showed that lactose has a larger hydration number (and has a more negative partial molar compressibility) than sucrose and maltose. In Figure 2 the corresponding values for aqueous glucose (monosaccharide) and raffinose (trisaccharide) solutions have also been shown. As
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ACCEPTED MANUSCRIPT can be seen, because of a cooperativity effect, aqueous raffinose solutions have a smaller water activity (or larger osmotic coefficient) values than all the investigated aqueous disaccharides solutions, which in turn have a smaller water activity (or larger osmotic coefficient) values than all the investigated aqueous monosaccharides solutions.
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Figure 3 shows the experimental osmotic coefficients and water activities for aqueous solutions of polyols: sorbitol, xylitol and maltitol. As can be seen, the values of the osmotic coefficients follow the order: maltitol > (sorbitol ≅ xylitol) and water activities increase in the order: maltitol < (sorbitol
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≅ xylitol). Maltitol, sorbitol and xylitol are obtained from the hydrogenation (reduction) of linear (acyclic) form of carbohydrates maltose, glucose and xylose, respectively; which their osmotic
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coefficients follow the order: maltose > Glucose > xylose. The reduction of aldose to alcohols leads to increased hydrophilic nature, because aldehyde functional group (existing in linear structure of carbohydrate) only can accept hydrogen bond from water but hydroxyl group can act as both hydrogen bond donor and acceptor. Besides, the study of the limiting partial molar excess heat 0
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capacity ( c p,ex ), which is a sensitive indicator about hydration interactions, has been shown that the 0
values of c p,ex for polyols (arabinitol, xylitol, ribitol, mannitol, glucitol and galactitol) are
0
EP
significantly larger than those for respective carbohydrates (arabinose, xylose, mannose, glucose and galactose). c p,ex is a measure of the effect of a change in environment on the freedom degree of
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solute, and the larger value of that for polyols may be attributed to their higher hydration due to the more ability for hydrogen bonding with water [26]. Accordingly it would be expected that, at the same molality, the water activity values for polyols aqueous solutions should be smaller than those for corresponding carbohydrates aqueous solutions (and about osmotic coefficient the reverse order is expected). In Figure 3, the obtained data for aqueous glucose, xylose and maltose solutions have also been shown. From this figure it is clear that, in the case of maltitol and xylitol, as expected, the values of osmotic coefficients for the polyols aqueous solutions are larger than those for the corresponding carbohydrates aqueous solutions. However, surprisingly, the values of water activity
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ACCEPTED MANUSCRIPT for the aqueous sorbitol solutions are larger than those for the aqueous glucose solutions. Of course, in this issue our data is in agreement with literature (see Figure 7b). In a binary solution, the osmotic coefficient can be related to the molality activity coefficient of
ln γ s
( m)
(m )
, using following equation [27]:
= (Φ − 1) + ∫
m
0
Φ −1 dm m
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solute, γ s
(5)
The composition dependence of the osmotic coefficient for non-electrolyte solutions can be
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expressed as a power series in the solute molality [28, 29], n
Φ = 1 + ∑ Ai m i
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i =1
(6)
The coefficients Ai can be obtained by least-squares fitting. Hence from equations (5) and (6), n
ln γ s( m ) = ∑ ( i =1
i +1 ) Ai m i i
(7)
Here, we found that by considering five terms (i=1,..,5) of the summation existing in equation (6),
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the concentration dependence of the osmotic coefficients are described very well, Φ = 1 + A1 m + A2 m 2 + A3 m 3 + A4 m 4 + A5 m 5 Then,
3 4 5 6 A2 m 2 + A3 m 3 + A4 m 4 + A5 m 5 2 3 4 5
EP
lnγ s(m) = 2 A1m +
(8)
(9)
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The values of coefficients Ai, have been given in Table 5. The dependence of osmotic coefficients and solute activity coefficients on the concentration has been shown in Figure 4 for all the investigated systems. As this figure shows, solute activity coefficients decrease in the same order of the osmotic coefficients. The values of γ s(m) have also been given in Table 3. The osmotic and activity coefficients can be used for determination of the excess molar Gibbs free energy, GmE , with the following equation [27]:
[
GmE = x s RT ln(γ s( m ) ) + 1 − Φ
]
(10)
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ACCEPTED MANUSCRIPT where xs is the solute mole fraction. In figure 5, the values of GmE for the investigated aqueous sugar solutions have been plotted. Some comparisons between our data and references have been done in Figures 6 and 7. As mentioned before, the reliable experimental water activity or osmotic coefficient data for aqueous
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sugar solutions at 308.15 K are scarce, so in this figures references data are often at 298.15 K. Figure 6 shows that osmotic coefficient values of glucose aqueous solutions at 308.15 K obtained in this work are between literature data at 298.15 K and 310.15 K and closer to 310.15 K than 298.15
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K. In addition, according to this figure, osmotic coefficients decrease by increasing temperature. Figure 7 reveals that, similar to our results, literature values of water activity for sucrose aqueous
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solutions are smaller than those for maltose aqueous solutions, as well as, literature values of osmotic coefficient for glucose aqueous solutions are larger than those for sorbitol aqueous solutions. Besides, as expected, it can be seen from Figure 7 that water activities and osmotic coefficients of aqueous sugar solutions respectively increase and decrease by increasing
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temperature. It should be noted that some of the osmotic coefficients data for aqueous sugar solutions reported in different articles by means of various methods disagree with each other (Figure 8). Given that the precision of VPO method in determining osmotic coefficients is much
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more than methods such as freezing point depression, hygrometry and isopiestic, the data presented in this work provide precise, reliable and up to date information about osmotic properties of these
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important systems.
4. Conclusion
Osmotic coefficient, water activity and vapor pressure of aqueous solutions of pentose monosaccharides: xylose, ribose and arabinose, hexose monosaccharides: glucose, fructose, galactose and mannose, disaccharides: sucrose, maltose and lactose, trisaccharide: raffinose and polyols: sorbitol, xylitol and maltitol were determined at 308.15 K from the vapor pressure osmometery measurements. It was found that the experimental osmotic coefficients and solute
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activity coefficients of the investigated aqueous solutions decrease in the order: raffinose > lactose > maltitol ≥ sucrose > maltose > (D-Glucose ≥ D-galactose) > (xylitol ≅ sorbitol) > (D-fructose ≥ Larabinose) > (D-xylose ≥ D-mannose) > D-ribose. In other words, because of a cooperativity effect, the experimental osmotic and solute activity coefficients of the aqueous carbohydrate solutions
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decrease in the order: trisaccharide > disaccharides > monosaccharides. Although the differences between the values of the water activity (and also vapor pressure) are very small, close examination of the obtained data indicates the reverse order to that observed for the osmotic coefficient.
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The results show that in the aqueous monosaccharide solutions the OH(4) arrangement doesn’t have any significant effect on the hydration of carbohydrates, However, the arrangements of OH(2) and
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OH(3) are very effective in this respect. The hydration of a carbohydrate is mostly dependent on the axial and equatorial arrangements of their hydroxyl groups. So that, the equatorial hydroxyl
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substituents (specially OH(2) and OH(3)) are more easily hydrated than axial.
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References [1] L. Ben Gaı¨da, C.G. Dussap, J.B. Gros, Variable hydration of small carbohydrates for predicting equilibrium properties in diluted and concentrated solutions, Food Chemistry 96 (2006 ) 387-401. [2] P.K. Banipal, T.S. Banipal, B.S. Lark, J.C. Ahluwalia, Partial molar heat capacities and volumes of some mono-, di- and tri-saccharides in water at 298.15, 308.15 and 318.15 K, J. Chem. Soc. Faraday Trans. 93 (1997) 81-87. [3] M. Baghbanbashi, G. Pazuki, A new hydrogen bonding local composition based model in obtaining phase behavior of aqueous solutions of sugars, J. Mol. Liq. 195 (2014) 47-53. [4] O.D. Bonner, W.H. Breazeale, Osmotic and Activity Coefficients of Some Nonelectrolytes, J. Chem. Eng. Data 10 (1965) 325-327. [5] K. Miyajima, M. Sawada, M. Nakagaki, Studies on aqueous solutions of saccharides. I. Activity coefficients of monosaccharides in aqueous solutions at 25 C, Bull. Chem. Soc. Jpn. 56 (1983) 1620-1623. [6] R.H. Stokes, R.A. Robinson, Interactions in Aqueous Nonelectrolyte Solutions. I. SoluteSolvent Equilibria, J. Phys. Chem. 70 (1966) 2126–2131. [7] Y.F. Hu, Z.C. Wang, Isopiestic studies on (mannitol+ sorbitol+ d-glucose)(aq) and two of the subsystems at the temperature 298.15 K, J. Chem. Thermodyn. 29 (1997) 879-884. [8] R.A. Robinson, R.H. Stokes, Activity coefficients in aqueous solutions of sucrose, mannitol and their mixtures at 25, J. Phys. Chem. 65 (1961) 1954-1958. [9] K. Miyajima, M. Sawada, M. Nakagaki, Studies on aqueous solutions of saccharides. II. Viscosity B-coefficients, apparent molar volumes, and activity coefficients of D-glucose, maltose, and maltotriose in aqueous solutions, Bull. Chem. Soc. Jpn. 56 (1983) 1954-1957. [10] V.E. Bower, R.A. Robinson, Isopiestic vapor pressure measurements of the ternary system: Sorbitol-Sodium Chloride-Water at 25, J. Phys. Chem. 67 (1963) 1540-1541. [11] O.D. Bonner, Osmotic and activity coefficients of sodium chloride-sorbitol and potassium chloride-sorbitol solutions at 25° C, J. Solut. Chem. 11 (1982) 315-324. [12] H. Uedaira, H. Uedaira, Activity coefficients of aqueous xylose and maltose solutions, Bull. Chem. Soc. Jpn. 42 (1969) 2137-2140. [13] C.R. Lerici, M. Piva, M.D. Rosa, Water activity and freezing point depression of aqueous solutions and liquid foods, J. Food Sci. 48 (1983) 1667-1669. [14] L. Ninni, M.S. Camargo, A.J.A. Meirelles, Water activity in polyol systems, J. Chem. Eng. Data 45 (2000) 654-660. [15] J.F. Comesaña, A. Correa, A.M. Sereno, Water activity in sorbitol or xylitol+ water and sorbitol or xylitol+ sodium chloride+ water systems at 20 C and 35 C, J. Chem. Eng. Data 46 (2001) 716-719. [16] C.F. Fontán, J. Chirife, The evaluation of water activity in aqueous solutions from freezing point depression, Int. J. Food Sci. Technol. 16 (1981) 21-30. [17] C.F. Fontan, J. Chirife, R. Boquet, Water activity in multicomponent non‐electrolyte solutions, Int. J. Food Sci. Technol. 16 (1981) 553-559. [18] L. Chuang, R.T. Toledo, Predicting the water activity of multicomponent systems from water sorption isotherms of individual components, J. Food Sci. 41 (1976) 922-927. [19] J.B. Taylor, J.S. Rowlinson, The thermodynamic properties of aqueous solutions of glucose, Trans. Faraday Soc. 51 (1955) 1183-1192. [20] E.C.W. Clarke, D.N. Glew, Evaluation of the Thermodynamic Functions for Aqueous Sodium Chloride from Equilibrium and Calorimetric Measurement below 154 ◦C, J. Phys. Chem. Ref. Data 14 (1985) 489-610. [21] J. Barthel, R. Neueder, and G. Lauermann, Vapor pressures of non-aqueous electrolyte solutions. Part 1. Alkali metal salts in methanol, J. Solution Chem. 14 (1985) 621–633. [22] J. A. Rard, R. F. Platford, and K. S. Pitzer, Activity Coefficients in Electrolyte Solutions, CRC Press. Boca Raton, FL, 1991, pp. 209–277.
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[23] H. Uedaira, M. Ikura, H. Uedaira, Natural-abundance oxygen-17 magnetic relaxation in aqueous solutions of carbohydrates, Bull. Chem. Soc. Jpn. 62 (1989) 1-4. [24] M.A. Kabayama, D. Patterson, The thermodynamics of mutarotation of some sugars: II. Theoretical consideration, Can. J. Chem. 36 (1958) 563-573. [25] S.A. Galema, H. Hoiland, Stereochemical aspects of hydration of carbohydrates in aqueous solutions. 3. Density and ultrasound measurements, J. Phys. Chem. 95 (1991) 5321-5326. [26] F. Franks, Physical Chemistry of Small Carbohydrates-Equilibrium Solution Properties. Pure Appl. Chem. 59 (1987) 1189–1202. [27] Prausnitz, J. M.; Lichtenthaler, R. N.; de Azevedo, E. G. Molecular Thermodynamics of FluidPhase Equilibria; Pearson Education, 1998. [28] R. Kolhapurkar, K. Patil, Studies of Volumetric and Activity Behaviors of Binary and Ternary Aqueous Solutions Containing β-Cyclodextrin and Glucose, J. Mol. Liq. 178 (2013) 185–191. [29] J.J. Kozak, W.S. Knight, W. Kauzmann, Solute‐Solute Interactions in Aqueous Solutions, J. Chem. Phys. 48 (1968) 675–690.
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ACCEPTED MANUSCRIPT Figure 1 Plot of the experimental osmotic coefficient, Φ, (1a) and water activity, aw, (1b) data of the investigated aqueous monosaccharides solutions as a function of molality, m / (mol.kg-1), of solutes at 308.15 K: ○, L (+)–Arabinose; ●, D (+)–Xylose; +, D (-)–Ribose; ◇, D (+)–Mannose; ▲, D (-)– Fructose; ×, D (+)– Galactose; △, D (+)–Glucose.
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Figure 2 Plot of the experimental osmotic coefficient, Φ, (2a) and water activity, aw, (2b) data of the investigated aqueous disaccharides solutions (as well as glucose and raffinose aqueous solutions for comparison with disaccharides) as a function of molality, m / (mol.kg-1), of solutes at 308.15 K: ○, Lactose; ●, Sucrose; +, Maltose; ◇, D (+)–Glucose; ▲, Raffinose.
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Figure 3 Plot of the experimental osmotic coefficient, Φ, (3a) and water activity, aw, (3b) data of the investigated aqueous polyols solutions as a function of molality, m / (mol.kg-1), of solutes at 308.15
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K: ○, Maltitol; ●, D (-)–Sorbitol; +, Xylitol; ◇, D (+)–Xylose; ▲, Maltose; ×, D (+)–Glucose.
Figure 4 Plot of the experimental osmotic coefficient, Φ, (4a) and solute activity coefficient, γ s( m ) , (4b) data of the investigated aqueous solutions as a function of solute molality, m / (mol.kg-1), at 308.15 K.
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Figure 5 Plot of the excess molar Gibbs free energy, GmE , of the investigated aqueous solutions as a function of solute molality, m / (mol.kg-1), at 308.15 K.
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Figure 6 Plot of the comparison between our data (solid lines and filled marker) and literatures (dotted lines and empty marker) for osmotic coefficients of D (+)-Glucose aqueous solutions: ●, our data at 308.15 K; ○, ref [4] at 310.15 K; ◇, ref [4] at 298.15 K; △, ref [6] at 298.15 K; □, ref [5] at 298.15 K; -, ref [7] at 298.15 K. Figure 7 Plot of the comparison between our data at 308.15 K (solid lines and filled marker) and literatures at 298.15 K (dotted lines and empty marker) for water activities, aw, (7a) of Sucrose and Maltose aqueous solutions: ●, our data (Maltose); ▲, our data (Sucrose); ○, ref [12] (maltose); △, ref [6] (Sucrose); □, ref [8] (sucrose) and for osmotic coefficients, Φ, (7b) of Sorbitol and Glucose aqueous solutions: ▲, our data (D (+)-Glucose); ■, our data (Sorbitol); △, ref [7] (D (+)-Glucose); □, ref [7] (Sorbitol). Figure 8 Plot of the comparison between our data and literatures for osmotic coefficients of sorbitol (8a) and xylitol (8b) aqueous solutions: ●, our data at 308.15 K; ○, ref [14] at 308.15 K; ×, ref [15] at 308.15 K; ◇, ref [10] at 298.15 K; △, ref [7] at 298.15 K; □, ref [11] at 298.15 K; +, ref [14] at 298.15 K.
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58.44
Merck Acros Merck Merck Merck Merck Merck Merck Merck Merck Merck Alfa Aesar Merck Alfa Aesar
none none none none none none none none none none none none none none
Merck
EP AC C
Final mass fraction purity ≥ 0.99 ≥ 0.99 ≥ 0.99 ≥ 0.995 ≥ 0.98 ≥ 0.98 ≥ 0.99 ≥ 0.98 0.99 ≥ 0.98 ≥ 0.97 0.99 ≥ 0.99 0.97
SC
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Purification method
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NaCl
Source
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Table 1 Specification of Chemical Samples 103⋅Molecular Chemical name weight (kg⋅mol-1) D (+) - Xylose 150.13 D (-) - Ribose 150.13 L (+) - Arabinose 150.13 D (+) - Glucose 180.16 D (+) - Galactose 180.16 D (+) - Mannose 180.16 D (-) - Fructose 180.16 Sucrose 342.29 Maltose monohydrate 360.32 Lactose monohydrate 360.32 Raffinose pentahydrate 594.52 Xylitol 152.15 D (-) - Sorbitol 182.17 Maltitol 344.32
was dried in an electrical oven at about 110 0C for 24 h prior to use
≥ 0.995
15
ACCEPTED MANUSCRIPT Table 2 Calibration Coefficients bi in equation 1.
b0
gain = 16, bridge voltage = 100% gain = 16, bridge voltage = 52.1%
-3
- 0.04102336
3.63567804 × 10
-3
b2 -4
- 1.46651770 × 10
-8
1.22600771 × 10
-11
7.88975520 × 10
-4
- 2.33960676 × 10
-7
8.61843277 × 10
-11
5.25320889 × 10
-3
- 1.06209327 × 10
M AN U TE D EP AC C
b3
3.18956224 × 10
SC
gain = 1, bridge voltage = 100%
1.04055427 × 10
b1
RI PT
mode of setting
-6
- 1.65155684 × 10
-10
16
ACCEPTED MANUSCRIPT Table 3 Experimental osmotic coefficient, Φ, water activity, aw, vapor pressure, p / (kPa) and solute activity coefficient, γ s(m) , data of the investigated aqueous solutions as a function of solute molality, m / (mol⋅kg-1), at 308.15 K m/
aw
Φ
p / (kPa)
-1
γ s(m)
0.9988
5.6252
0.9909
0.0332
0.9993
0.1355
0.9894
0.9976
5.6185
0.9832
0.0672
0.9973
0.2058
0.9874
0.9963
5.6111
0.9767
0.1346
0.9965
0.2784
0.9869
0.9951
5.6043
0.9713
0.2071
0.3372
0.9866
0.9940
5.5981
0.9677
0.2766
0.4237
0.9852
0.9925
5.5897
0.9634
0.3435
0.5011
0.9853
0.9911
5.5818
0.9605
0.5801
0.9850
0.9898
5.5744
0.6558
0.9853
0.9884
0.7393
0.9852
0.9870
0.8160
0.9857
0.9856
0.9059
0.9858
0.9840
1.0227
0.9859
0.9820
1.1649
0.9868
0.9795
1.3063
0.9870
1.6615
0.9881
2.9983
0.9994
5.6286
0.9981
0.9988
5.6252
0.9964
0.9976
5.6185
0.9934
SC
0.9970
0.9963
5.6111
0.9909
0.9956
0.9951
5.6043
0.9889
0.9951
0.9939
5.5976
0.9874
0.4151
0.9944
0.9926
5.5902
0.9861
0.9582
0.4952
0.9947
0.9912
5.5823
0.9850
5.5665
0.9565
0.5785
0.9949
0.9897
5.5739
0.9842
5.5586
0.9551
0.6498
0.9944
0.9884
5.5665
0.9836
TE D
M AN U
0.9950
0.9540
0.8204
0.9948
0.9854
5.5496
0.9825
5.5417
0.9531
0.9055
0.9945
0.9839
5.5411
0.9821
5.5304
0.9521
1.0411
0.9945
0.9815
5.5276
0.9814
5.5163
0.9512
1.1770
0.9944
0.9791
5.5140
0.9807
0.9770
5.5022
0.9504
1.3128
0.9942
0.9768
5.5010
0.9800
0.9709
5.4677
0.9487
1.6594
0.9950
0.9707
5.4666
0.9786
0.9919
0.9651
5.4350
0.9489
2.4020
1.0015
0.9576
5.3927
0.9844
0.9966
0.9589
5.4000
0.9524
3.2716
1.0159
0.9419
5.3041
1.0016
1.0019
0.9521
5.3616
0.9596
1.0074
0.9470
5.3329
0.9635
EP
5.5507
AC C
2.7220
γ s(m)
L (+) – Arabinose + water
0.0672
2.3380
p / (kPa)
(mol⋅kg )
D (+) - Xylose + water
1.9876
aw
Φ -1
RI PT
(mol⋅kg )
m/
Xylitol + water
D (-) - Ribose + water 0.0338
0.9992
0.9994
5.6286
0.9916
0.0672
0.9880
0.9988
5.6252
0.9841
0.0663
1.0022
0.9988
5.6252
1.0012
0.1353
0.9826
0.9976
5.6185
0.9707
0.1332
1.0021
0.9976
5.6185
1.0024
0.2041
0.9786
0.9964
5.6117
0.9597
0.2029
1.0016
0.9963
5.6111
1.0036
0.2789
0.9769
0.9951
5.6043
0.9499
17
ACCEPTED MANUSCRIPT 1.0023
0.9951
5.6043
1.0048
0.3505
0.9753
0.9939
5.5976
0.9424
0.3466
1.0028
0.9938
5.5970
1.0061
0.4242
0.9745
0.9926
5.5902
0.9362
0.4199
1.0037
0.9924
5.5891
1.0074
0.4990
0.9743
0.9913
5.5829
0.9312
0.4950
1.0046
0.9911
5.5818
1.0088
0.5801
0.9736
0.9899
5.5750
0.9270
0.5643
1.0050
0.9898
5.5744
1.0100
0.6538
0.9734
0.9886
5.5677
0.9240
0.6343
1.0053
0.9886
5.5677
1.0114
0.7165
0.9730
0.9875
5.5614
0.9219
0.7296
1.0059
0.9869
5.5581
1.0133
0.7426
0.9732
0.7920
1.0072
0.9857
5.5513
1.0146
0.8289
0.9730
0.8908
1.0085
0.9839
5.5411
1.0168
0.9054
0.9732
0.9999
1.0106
0.9820
5.5304
1.0193
1.0380
0.9735
1.1429
1.0125
0.9794
5.5157
1.0227
1.1830
1.2974
1.0147
0.9766
5.4999
1.0268
1.4531
1.4741
1.0166
0.9734
5.4819
1.0317
2.0274
1.0262
0.9632
5.4243
2.6463
1.0359
0.9518
3.2895
1.0423
4.4126
1.0478
5.5592
0.9212
0.9856
5.5507
0.9190
0.9843
5.5434
0.9173
0.9820
5.5304
0.9149
0.9735
0.9795
5.5163
0.9125
0.9745
0.9748
5.4898
0.9080
1.9881
0.9774
0.9656
5.4378
0.9007
1.0485
2.5940
0.9857
0.9550
5.3780
0.9061
5.3599
1.0673
3.2659
0.9944
0.9432
5.3114
0.9117
0.9401
5.2939
1.0834
0.9201
5.1811
1.1038
M AN U
TE D
0.9999
0.9990
0.1149
1.0009
0.9979
0.1727
1.0036
0.2306
1.0028
D (-) – Fructose + water
0.0559
0.9986
0.9990
5.6264
0.9978
0.1125
0.9958
0.9980
5.6207
0.9957
5.6264
1.0017
0.1714
0.9944
0.9969
5.6145
0.9938
5.6201
1.0035
0.2296
0.9949
0.9959
5.6089
0.9921
0.9969
5.6145
1.0052
0.2923
0.9947
0.9948
5.6026
0.9905
0.9958
5.6083
1.0070
0.3466
0.9945
0.9938
5.5970
0.9893
AC C
EP
0.0558
SC
0.9871
D (+) – Galactose + water
0.2878
RI PT
0.2718
1.0045
0.9948
5.6026
1.0086
0.4185
0.9946
0.9925
5.5897
0.9878
1.0057
0.9936
5.5959
1.0105
0.4792
0.9949
0.9914
5.5835
0.9868
1.0058
0.9926
5.5902
1.0121
0.5468
0.9947
0.9902
5.5767
0.9858
0.4829
1.0066
0.9913
5.5829
1.0140
0.6140
0.9951
0.9891
5.5705
0.9850
0.5526
1.0080
0.9900
5.5756
1.0158
0.6925
0.9951
0.9877
5.5626
0.9842
0.6174
1.0081
0.9888
5.5688
1.0174
0.7872
0.9955
0.9860
5.5530
0.9835
0.6818
1.0089
0.9877
5.5626
1.0190
0.9018
0.9950
0.9840
5.5417
0.9829
0.7847
1.0097
0.9858
5.5518
1.0214
1.0224
0.9947
0.9818
5.5293
0.9826
0.3548 0.4098
18
ACCEPTED MANUSCRIPT 1.0113
0.9838
5.5406
1.0239
1.1389
0.9949
0.9798
5.5180
0.9826
1.0093
1.0119
0.9818
5.5293
1.0264
1.2655
0.9949
0.9776
5.5056
0.9828
1.1379
1.0130
0.9794
5.5157
1.0293
1.7407
0.9972
0.9692
5.4582
0.9851
1.3084
1.0158
0.9763
5.4982
1.0333
2.4014
1.0057
0.9574
5.3916
0.9920
1.8502
1.0248
0.9664
5.4423
1.0503
2.9503
1.0142
0.9475
5.3357
1.0015
2.6098
1.0450
0.9521
5.3616
1.0844
3.6246
1.0266
0.9352
5.2663
1.0197
5.4239
1.0685
D (+) – Glucose + water 0.0557
1.0023
0.9990
5.6264
1.0021
0.1126
1.0050
0.9980
5.6207
1.0041
0.1128
0.9933
0.1685
1.0044
0.9970
5.6151
1.0059
0.2298
0.2236
1.0035
0.9960
5.6094
1.0076
0.3533
0.2913
1.0041
0.9947
5.6021
1.0095
0.4798
0.3539
1.0049
0.9936
5.5959
1.0111
0.4081
1.0057
0.9926
5.5902
0.4775
1.0059
0.9914
0.5382
1.0062
0.5708
RI PT
0.8958
0.9009
5.0727
1.0842
5.6207
0.9861
0.9890
0.9959
5.6089
0.9750
0.9840
0.9938
5.5970
0.9662
0.9828
0.9915
5.5840
0.9596
0.6097
0.9824
0.9893
5.5716
0.9548
1.0124
0.7659
0.9832
0.9865
5.5558
0.9510
5.5835
1.0141
0.9375
0.9836
0.9835
5.5389
0.9485
0.9903
5.5772
1.0155
1.1170
0.9842
0.9804
5.5214
0.9470
1.0077
0.9897
5.5739
1.0162
1.3041
0.9852
0.9771
5.5027
0.9463
0.6209
1.0075
0.9888
5.5688
1.0173
1.8290
0.9903
0.9679
5.4508
0.9461
0.6815
1.0085
0.9877
5.5626
1.0187
2.5437
0.9978
0.9553
5.3797
0.9515
0.7347
1.0086
0.9867
5.5569
1.0199
3.6589
1.0170
0.9352
5.2663
0.9727
0.7963
1.0087
0.9085
1.0102
M AN U
TE D
0.9856
5.5507
1.0213
0.9836
5.5394
1.0239
0.0296
0.9997
0.9995
5.6292
1.0070
AC C
1.0193
SC
0.9980
EP
D (+) – Mannose + water
Sucrose + water
1.0115
0.9816
5.5281
1.0267
0.0581
1.0007
0.9990
5.6264
1.0135
1.0139
0.9799
5.5185
1.0291
0.0904
1.0078
0.9984
5.6230
1.0205
1.0151
0.9780
5.5078
1.0322
0.1209
1.0130
0.9978
5.6196
1.0268
1.3226
1.0169
0.9761
5.4971
1.0355
0.1534
1.0169
0.9972
5.6162
1.0332
1.5688
1.0225
0.9715
5.4711
1.0442
0.1988
1.0193
0.9964
5.6117
1.0416
1.8406
1.0301
0.9664
5.4423
1.0555
0.2535
1.0253
0.9953
5.6055
1.0511
2.3864
1.0437
0.9561
5.3842
1.0825
0.3157
1.0283
0.9942
5.5993
1.0610
2.9452
1.0609
0.9453
5.3233
1.1129
0.3938
1.0319
0.9927
5.5908
1.0725
1.1093 1.2150
19
ACCEPTED MANUSCRIPT 3.6262
1.0783
0.9320
5.2482
1.1483
0.4770
1.0352
0.9911
5.5818
1.0838
4.8470
1.1102
0.9076
5.1105
1.2176
0.5567
1.0393
0.9896
5.5733
1.0940
0.5822
1.0405
0.9891
5.5705
1.0971
0.9979
0.9995
5.6292
1.0008
0.6480
1.0417
0.9879
5.5637
1.1051
0.0558
1.0008
0.9990
5.6264
1.0016
0.7265
1.0471
0.9864
5.5552
1.1145
0.1110
0.9992
0.9980
5.6207
1.0030
0.8492
1.0528
0.9840
5.5417
1.1293
0.1676
1.0032
0.9970
5.6151
1.0041
0.9710
1.0585
0.9817
5.5287
1.1446
0.2296
1.0022
0.9959
5.6089
1.0052
1.0875
1.0651
0.9793
5.5152
1.1601
0.2892
1.0035
0.9948
5.6026
1.0061
1.1856
1.0675
0.9775
5.5050
1.1742
0.3523
1.0028
0.9937
5.5964
1.0069
1.2747
0.4124
1.0037
0.9926
5.5902
1.0075
1.9957
0.4781
1.0033
0.9914
5.5835
1.0081
2.6794
0.5436
1.0028
0.9902
5.5767
1.0086
0.6109
1.0031
0.9890
5.5699
1.0090
0.6764
1.0033
0.9878
5.5631
1.0095
0.7778
1.0033
0.9860
5.5530
1.0102
0.8812
1.0035
0.9842
0.9996
1.0044
0.9821
1.1116
1.0056
0.9801
1.2843
1.0075
0.9770
1.7230
1.0129
2.3421
1.0272
3.6449
0.9756
5.4943
1.1878
1.1486
0.9595
5.4034
1.3297
1.2015
0.9437
5.3142
1.4916
3.4118
1.2484
0.9261
5.2149
1.6407
3.9268
1.2757
0.9137
5.1449
1.7530
TE D
M AN U
1.0741
Maltose monohydrate + water
0.0280
0.9905
0.9995
5.6292
1.0015
1.0110
0.0568
1.0036
0.9990
5.6264
1.0032
5.5310
1.0121
0.1006
0.9985
0.9982
5.6218
1.0060
5.5197
1.0134
0.1463
1.0034
0.9974
5.6173
1.0093
5.5022
1.0159
0.2069
1.0070
0.9963
5.6111
1.0141
0.9690
5.4570
1.0255
0.2737
1.0123
0.9950
5.6038
1.0197
0.9576
5.3927
1.0458
0.3055
1.0138
0.9944
5.6004
1.0225
1.0411
0.9461
5.3278
1.0691
0.3739
1.0173
0.9932
5.5936
1.0285
1.0572
0.9329
5.2533
1.0975
0.4474
1.0200
0.9918
5.5857
1.0351
0.5051
1.0218
0.9907
5.5795
1.0402
EP
5.5428
AC C
2.9559
RI PT
0.0278
SC
D (-) – Sorbitol + water
Lactose monohydrate + water
0.0279
0.9946
0.9995
5.6292
0.9975
0.5739
1.0236
0.9895
5.5727
1.0463
0.1155
1.0106
0.9979
5.6201
1.0076
0.6801
1.0270
0.9875
5.5614
1.0553
0.2049
1.0223
0.9962
5.6105
1.0315
0.8153
1.0304
0.9850
5.5473
1.0662
0.2572
1.0299
0.9952
5.6049
1.0471
0.9512
1.0363
0.9824
5.5327
1.0767
0.3590
1.0465
0.9933
5.5942
1.0761
1.1085
1.0429
0.9794
5.5157
1.0888
20
ACCEPTED MANUSCRIPT 0.4626
1.0575
0.9912
5.5823
1.1021
1.2732
1.0501
0.9762
5.4977
1.1022
0.5817
1.0645
0.9889
5.5693
1.1272
1.7770
1.0776
0.9661
5.4407
1.1586
0.6433
1.0665
0.9877
5.5626
1.1357
2.5813
1.1408
0.9483
5.3402
1.2858
Raffinose pentahydrate + water
Maltitol + water
1.0015
0.9994
5.6286
1.0068
0.0292
0.9903
0.9995
5.6292
1.0030
0.1059
1.0253
0.9980
5.6207
1.0378
0.1187
0.9976
0.9979
5.6201
1.0123
0.1837
1.0401
0.9966
5.6128
1.0782
0.2190
1.0116
0.9960
5.6094
1.0232
0.2667
1.0623
0.9949
5.6032
1.1195
0.3226
1.0186
0.9941
5.5987
1.0349
0.3581
1.0832
0.9930
5.5925
1.1689
0.4282
1.0276
0.9921
5.5874
1.0475
0.4515
1.1172
0.9910
5.5812
1.2370
0.5127
1.0308
0.9905
5.5784
1.0580
0.4902
1.1340
0.9900
5.5756
1.2712
0.5925
1.0322
0.9890
5.5699
1.0684
0.6205
1.1677
0.9870
5.5586
1.3640
0.7740
1.0489
0.9855
5.5502
1.0936
0.9158
1.0599
0.9827
5.5343
1.1150
1.0543
1.0665
0.9799
5.5185
1.1373
1.2607
1.0814
0.9757
5.4948
1.1734
1.9178
1.1510
0.9610
5.4119
1.3103
2.6448
1.2172
0.9437
5.3142
1.4894
3.5914
1.2724
0.9210
5.1861
1.6973
TE D
M AN U
SC
RI PT
0.0343
AC C
respectively.
EP
The uncertainty in m, Φ, aw and p was ±2·10-4 mol·kg-1, ±1·10-3, ±1·10-4 and ±1·10-3 kPa
21
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Table 4 Arrangements of the hydroxyl group substituent at C-2, C-3 and C-4 of the investigated carbohydrates Carbohydrate OH(2) OH(3) OH(4) D (+) - Xylose equatorial equatorial equatorial D (-) - Ribose equatorial axial equatorial L (+) - Arabinose equatorial equatorial axial D (+) - Glucose equatorial equatorial equatorial D (+) - Galactose equatorial equatorial axial D (+) - Mannose axial equatorial equatorial
22
ACCEPTED MANUSCRIPT Table 5 Parameters of equations (8) and (9), together with the standard deviations (σ). A2
A3
A4
A5
σ
arabinose
-0.029649
0.056041
-0.046525
0.017018
-0.002154
0.0004
ribose
-0.129756
0.215040
-0.155451
0.050534
-0.005947
0.0019
xylose
-0.073976
0.123956
-0.089892
0.029890
-0.003625
0.0010
Fructose
-0.020900
0.023522
-0.010230
0.002296
-0.000184
0.0012
galactose
0.015149
0.001193
-0.010875
0.008062
-0.001514
0.0005
glucose
0.019808
-0.020858
0.017022
-0.004480
0.000388
0.0009
mannose
-0.069783
0.095547
-0.056030
0.015449
-0.001572
0.0006
Lactose monohydrate
-0.080174
1.803325
-5.671610
7.771960
-4.081269
0.0022
maltose monohydrate
0.024829
0.077617
-0.117831
0.065921
-0.011698
0.0031
sucrose
0.121473
-0.146152
0.114475
Raffinose pentahydrate
0.036862
2.845706
-14.533289
xylitol
0.009091
-0.002815
0.005494
sorbitol
0.015471
-0.028548
0.023684
maltitol
0.050830
0.007881
0.008009
EP AC C
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A1
-0.033626
0.003338
0.0026
30.372758
-21.539128
0.0019
-0.001961
0.000200
0.0005
-0.006781
0.000668
0.0009
-0.002857
0.000155
0.0045
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solute
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ACCEPTED MANUSCRIPT Scheme 1 OH
D-Xylose
L-Arabinose
O
D-Ribose O
O
HO
HO HO
HO OH
OH
OH
OH
OH
OH
OH D-Galactose
OHOH
O
OH
OH O
O
HO HO
HO HO
HO OH
OH
OH
OH
CH2OH
Xylitol
D-Sorbitol
OH
OH
OH HO HO
OH
HO HO
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O
OH
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OH
D-Fructose
D-Mannose
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OH D-Glucose
OH
OH
OH
Sucrose CH2OH
OH
OH
CH2OH
Lactose
OH
O
HO HO
CH2OH
CH2OH OH
O
OH
O
O
HO
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O
OH
CH2OH
O
OH
HO OH
CH2OH
OH
Maltose
O
HO HO
CH2OH
OH
Maltitol O
CH2OH
OH
O
O
OH
HO
HO
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O
CH2OH
HO HO
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CH2OH
OH OH
OH OH OH
CH2OH HO
O OH
Raffinose
O O HO HO
CH2OH OH
O
OH
O CH2OH OH
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Figure 1b
Figure 1a
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24
Figure 1b
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Figure 2a
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25
Figure 2b
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Figure 3a
AC C
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26
Figure 3b
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1.12 1.08 1.04
1.5 1.4 1.3 1.2 1.1
1.00 0.96 1
2
3
4 -1
m / mol.kg
Figure 4a
5
6
EP
0
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1.0
AC C
Φ
1.16
1.6
raffinose lactose maltitol sucrose maltose glucose galactose xylitol sorbitol fructose arabinose xylose mannose ribose
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1.20
1.7
γs
1.24
1.8
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raffinose lactose maltitol sucrose maltose glucose galactose xylitol sorbitol fructose arabinose xylose mannose ribose
1.28
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27
0.9 0
1
2
3
4 -1
m / mol.kg
Figure 4b
5
6
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28
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50
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40
-1
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30 20
E
Gm / J.mol
raffinose lactose maltitol sucrose maltose glucose galactose xylitol sorbitol fructose arabinose xylose mannose ribose
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10 0
EP
-10 1
2
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0
3
4 -1
m / mol.kg
Figure 5
5
6
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29
Figure 6
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Figure 7a
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30
Figure 7b
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Figure 8a
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31
Figure 8b
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• VLE properties of carbohydrate aqueous solutions were studied • Several monosaccharides, disaccharides, trisaccharides and polyols were studied • Effect of carbohydrates stereochemistry on the VLE of their aqueous solutions • Effect of carbohydrates structure on the VLE of their aqueous solutions
S0378-3812(16)30088-7
DOI:
10.1016/j.fluid.2016.02.030
Reference:
FLUID 11019
To appear in:
Fluid Phase Equilibria
Received Date: 8 January 2016 Revised Date:
14 February 2016
Accepted Date: 17 February 2016
Please cite this article as: N. Ebrahimi, R. Sadeghi, Osmotic Properties of Carbohydrate Aqueous Solutions, Fluid Phase Equilibria (2016), doi: 10.1016/j.fluid.2016.02.030. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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ACCEPTED MANUSCRIPT Osmotic Properties of Carbohydrate Aqueous Solutions
Nosaibah Ebrahimi, Rahmat Sadeghi∗
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Department of Chemistry, University of Kurdistan, Sanandaj, Iran
Abstract
Precise systematic osmotic coefficient measurements have been carried out for aqueous solutions of
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different carbohydrates and polyols by using vapor pressure osmometry (VPO) method. Herein, in order to investigate the effect of structure and stereochemistry of solutes on the vapor-liquid
solutions
containing
pentose
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equilibria behavior of aqueous solutions, we studied the osmotic properties of binary aqueous sugar monosaccharides
(xylose,
ribose
and
arabinose),
hexose
monosaccharides (glucose, fructose, galactose and mannose), disaccharides (sucrose, maltose and lactose), trisaccharide (raffinose) and polyols (sorbitol, xylitol and maltitol) at 308.15 K and in the
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extended concentration range. From the experimental osmotic coefficient data, the values of water activity and vapor pressure of the investigated solutions were obtained.
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Solutions
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Keywords: Vapor pressure osmometry; Osmotic coefficient; Activity; Carbohydrate; Aqueous
∗
Corresponding author. Tel.: +98 87 33624133; fax: +98 87 33660075. E-mail address: [email protected] and [email protected]
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ACCEPTED MANUSCRIPT 1. Introduction Carbohydrates which are a large natural resource have long interested chemists and biochemists because of their predominant role in biological and industrial applications. An important fraction of carbohydrates is made up of the smaller building units, namely sugar monomers and oligomers, and
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their aqueous solutions are mainly associated with the processing and the preservation of foods [1]. Thermodynamics investigations of aqueous carbohydrates solutions will be helpful in the precise design of operations and equipment used in food industries including chemical feed stocks, food
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production, and preservation of processed foods as well as in the study of the reaction conditions (e.g. feasibility and optimization) of currently employed industrial processes such as enzymatic
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conversion of biomass to useful chemicals [2]. As an example, water activity of solutions can be controlled by freeze drying and evaporation processes in order to reduce microorganism's growth and osmotic pressure caused by high concentrations of sugars that also inhibit food contaminations [3]. Although, a systematic and extensive study of water activities could contribute to a better
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understanding of the sugars hydration mode, which is a topic of considerable importance, a comprehensive understanding in this respect is yet to emerge. In the present work, for the first time, systematic vapor pressure osmometry (VPO) measurements
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have been carried out for several binary aqueous sugar solutions containing pentose monosaccharides, hexose monosaccharides, disaccharides, trisaccharide and polyols, at 308.15 K
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and in the extended concentration range in order to comprehensive study of vapor-liquid equilibrium of these systems and precise determine water activity and osmotic coefficients of them. Although previously water activity and osmotic coefficient data have been reported in the literatures for some aqueous carbohydrate solutions from isopiestic [4-12], hygrometry [13-15], freezing point depression [16, 17] and manometry [18, 19] methods, but these techniques aren’t precise as VPO, the number of data reported in the dilute concentration region is limited, none of them is an extensive study, and besides those data have often been reported at 298.15 K (except water activity obtained from the freezing point depression method which is the activity at the corresponding
3
ACCEPTED MANUSCRIPT freezing point temperature and may be had considerable difference with water activity at room temperature (298.15 K) or human body temperature (310.15 K)).
2. Experimental Section
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2.1. Materials The properties of the chemicals used in this work have been listed in Table 1 and their structures have been presented in Scheme 1. Given that in aqueous solutions pyranose conformation of the
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investigated monosaccharides is more favored than furanose conformation, in scheme 1 only pyranose form have been drawn for all the monosaccharides. The chemicals were used without
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further purification and double distilled and deionized water was used.
2.2. Methods
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All the solutions were prepared by mass on a Sartorius CP124S balance precise to within ±1·10-7 kg. The VPO measurements were performed using an Osmomat K-7000 (Knauer Inc.) at 308.15 K. The cell temperature was controlled electronically within ±1·10-3 K. The instrument consists of two
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thermistors (1 and 2) placed in an airtight cell (its gas phase is saturated by solvent vapor) which measure resistance changes caused by changes in temperature. Initially, a droplet of pure water is
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attached to both thermistors with the help of a microsyringe, and after equilibration (∼5 min), the reading is adjusted to zero. After that, the pure water on thermistor 1 is replaced by the carbohydrate solution. Because of the condensation of water from the vapor phase into the carbohydrate solution, the thermistor 1 will be warmed and vapor pressure rises. This condensation process continues until the vapor pressure of the carbohydrate solution equals to the vapor pressure of pure water. In this steady state (a time of 4–8 min suffices to reach it), the thermistors measure the resistance differences (R) due to the change of temperature (T) between the two thermistors. T is proportional to R, when T is small. Initially, the instrument was calibrated using aqueous
4
ACCEPTED MANUSCRIPT NaCl solutions as reference and from which a correlation between the panel readings and the corresponding concentrations of the NaCl solutions (and therefore their osmotic coefficients) was obtained. After that, the measurements for the different aqueous carbohydrates solutions were carried out in the same conditions. In this work, we performed experiments with three different
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modes of instrument setting, hence the instrument was calibrated with aqueous NaCl solutions at three conditions: (bridge voltage = 100 %, gain = 16), (bridge voltage = 52.1 %, gain = 16) and (bridge voltage = 100 % and gain = 1) for dilute, middle and concentrated regions, respectively. The
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following relation was used to correlate instrument panel reading (signal, SI) and NaCl molality
m NaCl = b0 + b1SI + b2 SI 2 + b3SI 3
(1)
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(mNaCl):
where b0, b1, b2 and b3 are calibration constants and their values are reported in Table 2. The osmotic coefficient, Φ, of a carbohydrate solution with molality m which has a same instrument reading as a sodium chloride solution with molality mNaCl, was obtained according to:
ν NaCl m NaCl Φ NaCl m
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Φ=
(2)
where ν NaCl is the stoichiometric number of NaCl. ΦNaCl is the osmotic coefficient for aqueous
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solutions of NaCl with molality mNaCl calculated from the correlation of Colin et al.[20] The
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uncertainty in the measurement of osmotic coefficient was found to be better than ± 1·10-3.
3. Result and Discussion
The osmotic coefficients of the systems investigated at 308.15 K are given in Table 3. From the experimental osmotic coefficient data, the values of water activity and vapor pressure for the solutions were determined through the following equations [21]:
mM w Φ a w = exp − 1000
(3)
5
(
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)(
p B o − Vwo p − p wo ln a w = ln o + w RT pw
)
(4)
where Mw is the molecular weight of the solvent, Bwo is the second virial coefficient of water vapor, Vwo is the molar volume of liquid water, and p wo is the vapor pressure of pure water. The value of
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Bwo at 308.15 K equals -1016.75 cm3.mol-1, where calculated using the equation provided by Rard
and Platford [22]. The obtained water activities and vapor pressures data of the systems investigated at 308.15 K are also given in Table 3.
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Figure 1 shows the experimental osmotic coefficients and water activities for monosaccharides: D-
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xylose, D-ribose, L-arabinose, D-mannose, D-fructose, D-galactose and D-glucose. As can be seen, the values of the osmotic coefficients follow the order: (D-Glucose ≥ D-galactose) > (D-fructose ≥ L-arabinose) > (D-xylose ≥ D-mannose) > D-ribose. Although the differences between the values of the water activities (and also vapor pressures) are very small, close examination of Figure 1b
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indicates the reverse order to that observed for the osmotic coefficients. As can be seen, except for D-mannose, water activities of aqueous solutions of hexose monosaccharides are smaller than that of pentose monosaccharides. This is because the hexose monosaccharides have more hydroxyl
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groups (hydrophilic group) in their structures than the pentose monosaccharides. The hydration of a
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carbohydrate is mostly dependent on the axial and equatorial arrangements of its hydroxyl groups. Equatorial hydroxyl substituents are more easily hydrated than axial. In Table 4, the arrangements of the hydroxyl groups substituent at C-2, C-3 and C-4 of the investigated pentose and hexose monosaccharides have been given (since fructose is a ketohexose monosaccharide, there are some differences between its structure and geometry with other investigated hexose monosaccharides which are aldohexose (see Scheme1), so in this table hydroxyl groups position of fructose have not been attended). The only difference between D-xylose and L-arabinose (and also between Dglucose and D-galactose) is that D-xylose (and D-glucose) has an equatorial OH(4), but L-arabinose (and D-galactose) has an axial OH(4). The smaller values of water activity for L-arabinose than D-
6
ACCEPTED MANUSCRIPT xylose as well as the similar water activity values for D-glucose and D-galactose indicate that the arrangement of OH(4) doesn’t have a significant effect on the carbohydrate hydration. However, the smaller values of water activity for D-xylose than D-ribose as well as that for D-glucose than Dmannose indicate that the arrangements of OH(2) and OH(3) greatly affect the hydration of
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carbohydrates. The dynamic hydration numbers of hexose monosaccharides in aqueous solutions obtained from the natural-abundance oxygen-17 magnetic relaxation follow the trend: glucose > galactose > fructose > mannose [23] which is in agreement with the results obtained in this work. In
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fact, the equatorial OH groups are able to interact with water in a manner which forms a long-lived hydration structure, since equatorial OH groups on pyranose sugars match the unperturbed water
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lattice [24].
The experimental osmotic coefficients and water activities of the investigated aqueous disaccharides solutions are shown in Figure 2. It should be noted that in the case of lactose and raffinose because of low carbohydrate water solubility, osmotic properties measurements have been
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done just in the concentrations below 0.7 mol.kg-1. As can be seen, the values of the osmotic coefficients and water activities respectively follow the order: lactose > sucrose > maltose and lactose < sucrose < maltose. Type of two constituent monosaccharide units of a disaccharide and
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also the position and mode of linkage between monosaccharides affect the disaccharide hydrophilic degree. From the trend obtained for water activity of monosaccharide solutions, we expect the
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trend: maltose (consist of two glucose units) < lactose (consist of a glucose and a galactose units) < sucrose (consist of a glucose and a fructose units) for the water activity of the investigated disaccharide solutions. The observed unexpectedly larger values for water activity of aqueous maltose solutions may be aroused from that maltose can form an intramolecular hydrogen bond in water [25]. Similarly, Galema et al.[25] from the density and ultrasound measurements of aqueous disaccharide solutions showed that lactose has a larger hydration number (and has a more negative partial molar compressibility) than sucrose and maltose. In Figure 2 the corresponding values for aqueous glucose (monosaccharide) and raffinose (trisaccharide) solutions have also been shown. As
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ACCEPTED MANUSCRIPT can be seen, because of a cooperativity effect, aqueous raffinose solutions have a smaller water activity (or larger osmotic coefficient) values than all the investigated aqueous disaccharides solutions, which in turn have a smaller water activity (or larger osmotic coefficient) values than all the investigated aqueous monosaccharides solutions.
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Figure 3 shows the experimental osmotic coefficients and water activities for aqueous solutions of polyols: sorbitol, xylitol and maltitol. As can be seen, the values of the osmotic coefficients follow the order: maltitol > (sorbitol ≅ xylitol) and water activities increase in the order: maltitol < (sorbitol
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≅ xylitol). Maltitol, sorbitol and xylitol are obtained from the hydrogenation (reduction) of linear (acyclic) form of carbohydrates maltose, glucose and xylose, respectively; which their osmotic
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coefficients follow the order: maltose > Glucose > xylose. The reduction of aldose to alcohols leads to increased hydrophilic nature, because aldehyde functional group (existing in linear structure of carbohydrate) only can accept hydrogen bond from water but hydroxyl group can act as both hydrogen bond donor and acceptor. Besides, the study of the limiting partial molar excess heat 0
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capacity ( c p,ex ), which is a sensitive indicator about hydration interactions, has been shown that the 0
values of c p,ex for polyols (arabinitol, xylitol, ribitol, mannitol, glucitol and galactitol) are
0
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significantly larger than those for respective carbohydrates (arabinose, xylose, mannose, glucose and galactose). c p,ex is a measure of the effect of a change in environment on the freedom degree of
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solute, and the larger value of that for polyols may be attributed to their higher hydration due to the more ability for hydrogen bonding with water [26]. Accordingly it would be expected that, at the same molality, the water activity values for polyols aqueous solutions should be smaller than those for corresponding carbohydrates aqueous solutions (and about osmotic coefficient the reverse order is expected). In Figure 3, the obtained data for aqueous glucose, xylose and maltose solutions have also been shown. From this figure it is clear that, in the case of maltitol and xylitol, as expected, the values of osmotic coefficients for the polyols aqueous solutions are larger than those for the corresponding carbohydrates aqueous solutions. However, surprisingly, the values of water activity
8
ACCEPTED MANUSCRIPT for the aqueous sorbitol solutions are larger than those for the aqueous glucose solutions. Of course, in this issue our data is in agreement with literature (see Figure 7b). In a binary solution, the osmotic coefficient can be related to the molality activity coefficient of
ln γ s
( m)
(m )
, using following equation [27]:
= (Φ − 1) + ∫
m
0
Φ −1 dm m
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solute, γ s
(5)
The composition dependence of the osmotic coefficient for non-electrolyte solutions can be
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expressed as a power series in the solute molality [28, 29], n
Φ = 1 + ∑ Ai m i
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i =1
(6)
The coefficients Ai can be obtained by least-squares fitting. Hence from equations (5) and (6), n
ln γ s( m ) = ∑ ( i =1
i +1 ) Ai m i i
(7)
Here, we found that by considering five terms (i=1,..,5) of the summation existing in equation (6),
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the concentration dependence of the osmotic coefficients are described very well, Φ = 1 + A1 m + A2 m 2 + A3 m 3 + A4 m 4 + A5 m 5 Then,
3 4 5 6 A2 m 2 + A3 m 3 + A4 m 4 + A5 m 5 2 3 4 5
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lnγ s(m) = 2 A1m +
(8)
(9)
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The values of coefficients Ai, have been given in Table 5. The dependence of osmotic coefficients and solute activity coefficients on the concentration has been shown in Figure 4 for all the investigated systems. As this figure shows, solute activity coefficients decrease in the same order of the osmotic coefficients. The values of γ s(m) have also been given in Table 3. The osmotic and activity coefficients can be used for determination of the excess molar Gibbs free energy, GmE , with the following equation [27]:
[
GmE = x s RT ln(γ s( m ) ) + 1 − Φ
]
(10)
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ACCEPTED MANUSCRIPT where xs is the solute mole fraction. In figure 5, the values of GmE for the investigated aqueous sugar solutions have been plotted. Some comparisons between our data and references have been done in Figures 6 and 7. As mentioned before, the reliable experimental water activity or osmotic coefficient data for aqueous
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sugar solutions at 308.15 K are scarce, so in this figures references data are often at 298.15 K. Figure 6 shows that osmotic coefficient values of glucose aqueous solutions at 308.15 K obtained in this work are between literature data at 298.15 K and 310.15 K and closer to 310.15 K than 298.15
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K. In addition, according to this figure, osmotic coefficients decrease by increasing temperature. Figure 7 reveals that, similar to our results, literature values of water activity for sucrose aqueous
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solutions are smaller than those for maltose aqueous solutions, as well as, literature values of osmotic coefficient for glucose aqueous solutions are larger than those for sorbitol aqueous solutions. Besides, as expected, it can be seen from Figure 7 that water activities and osmotic coefficients of aqueous sugar solutions respectively increase and decrease by increasing
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temperature. It should be noted that some of the osmotic coefficients data for aqueous sugar solutions reported in different articles by means of various methods disagree with each other (Figure 8). Given that the precision of VPO method in determining osmotic coefficients is much
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more than methods such as freezing point depression, hygrometry and isopiestic, the data presented in this work provide precise, reliable and up to date information about osmotic properties of these
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important systems.
4. Conclusion
Osmotic coefficient, water activity and vapor pressure of aqueous solutions of pentose monosaccharides: xylose, ribose and arabinose, hexose monosaccharides: glucose, fructose, galactose and mannose, disaccharides: sucrose, maltose and lactose, trisaccharide: raffinose and polyols: sorbitol, xylitol and maltitol were determined at 308.15 K from the vapor pressure osmometery measurements. It was found that the experimental osmotic coefficients and solute
10
ACCEPTED MANUSCRIPT
activity coefficients of the investigated aqueous solutions decrease in the order: raffinose > lactose > maltitol ≥ sucrose > maltose > (D-Glucose ≥ D-galactose) > (xylitol ≅ sorbitol) > (D-fructose ≥ Larabinose) > (D-xylose ≥ D-mannose) > D-ribose. In other words, because of a cooperativity effect, the experimental osmotic and solute activity coefficients of the aqueous carbohydrate solutions
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decrease in the order: trisaccharide > disaccharides > monosaccharides. Although the differences between the values of the water activity (and also vapor pressure) are very small, close examination of the obtained data indicates the reverse order to that observed for the osmotic coefficient.
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The results show that in the aqueous monosaccharide solutions the OH(4) arrangement doesn’t have any significant effect on the hydration of carbohydrates, However, the arrangements of OH(2) and
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OH(3) are very effective in this respect. The hydration of a carbohydrate is mostly dependent on the axial and equatorial arrangements of their hydroxyl groups. So that, the equatorial hydroxyl
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substituents (specially OH(2) and OH(3)) are more easily hydrated than axial.
11
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References [1] L. Ben Gaı¨da, C.G. Dussap, J.B. Gros, Variable hydration of small carbohydrates for predicting equilibrium properties in diluted and concentrated solutions, Food Chemistry 96 (2006 ) 387-401. [2] P.K. Banipal, T.S. Banipal, B.S. Lark, J.C. Ahluwalia, Partial molar heat capacities and volumes of some mono-, di- and tri-saccharides in water at 298.15, 308.15 and 318.15 K, J. Chem. Soc. Faraday Trans. 93 (1997) 81-87. [3] M. Baghbanbashi, G. Pazuki, A new hydrogen bonding local composition based model in obtaining phase behavior of aqueous solutions of sugars, J. Mol. Liq. 195 (2014) 47-53. [4] O.D. Bonner, W.H. Breazeale, Osmotic and Activity Coefficients of Some Nonelectrolytes, J. Chem. Eng. Data 10 (1965) 325-327. [5] K. Miyajima, M. Sawada, M. Nakagaki, Studies on aqueous solutions of saccharides. I. Activity coefficients of monosaccharides in aqueous solutions at 25 C, Bull. Chem. Soc. Jpn. 56 (1983) 1620-1623. [6] R.H. Stokes, R.A. Robinson, Interactions in Aqueous Nonelectrolyte Solutions. I. SoluteSolvent Equilibria, J. Phys. Chem. 70 (1966) 2126–2131. [7] Y.F. Hu, Z.C. Wang, Isopiestic studies on (mannitol+ sorbitol+ d-glucose)(aq) and two of the subsystems at the temperature 298.15 K, J. Chem. Thermodyn. 29 (1997) 879-884. [8] R.A. Robinson, R.H. Stokes, Activity coefficients in aqueous solutions of sucrose, mannitol and their mixtures at 25, J. Phys. Chem. 65 (1961) 1954-1958. [9] K. Miyajima, M. Sawada, M. Nakagaki, Studies on aqueous solutions of saccharides. II. Viscosity B-coefficients, apparent molar volumes, and activity coefficients of D-glucose, maltose, and maltotriose in aqueous solutions, Bull. Chem. Soc. Jpn. 56 (1983) 1954-1957. [10] V.E. Bower, R.A. Robinson, Isopiestic vapor pressure measurements of the ternary system: Sorbitol-Sodium Chloride-Water at 25, J. Phys. Chem. 67 (1963) 1540-1541. [11] O.D. Bonner, Osmotic and activity coefficients of sodium chloride-sorbitol and potassium chloride-sorbitol solutions at 25° C, J. Solut. Chem. 11 (1982) 315-324. [12] H. Uedaira, H. Uedaira, Activity coefficients of aqueous xylose and maltose solutions, Bull. Chem. Soc. Jpn. 42 (1969) 2137-2140. [13] C.R. Lerici, M. Piva, M.D. Rosa, Water activity and freezing point depression of aqueous solutions and liquid foods, J. Food Sci. 48 (1983) 1667-1669. [14] L. Ninni, M.S. Camargo, A.J.A. Meirelles, Water activity in polyol systems, J. Chem. Eng. Data 45 (2000) 654-660. [15] J.F. Comesaña, A. Correa, A.M. Sereno, Water activity in sorbitol or xylitol+ water and sorbitol or xylitol+ sodium chloride+ water systems at 20 C and 35 C, J. Chem. Eng. Data 46 (2001) 716-719. [16] C.F. Fontán, J. Chirife, The evaluation of water activity in aqueous solutions from freezing point depression, Int. J. Food Sci. Technol. 16 (1981) 21-30. [17] C.F. Fontan, J. Chirife, R. Boquet, Water activity in multicomponent non‐electrolyte solutions, Int. J. Food Sci. Technol. 16 (1981) 553-559. [18] L. Chuang, R.T. Toledo, Predicting the water activity of multicomponent systems from water sorption isotherms of individual components, J. Food Sci. 41 (1976) 922-927. [19] J.B. Taylor, J.S. Rowlinson, The thermodynamic properties of aqueous solutions of glucose, Trans. Faraday Soc. 51 (1955) 1183-1192. [20] E.C.W. Clarke, D.N. Glew, Evaluation of the Thermodynamic Functions for Aqueous Sodium Chloride from Equilibrium and Calorimetric Measurement below 154 ◦C, J. Phys. Chem. Ref. Data 14 (1985) 489-610. [21] J. Barthel, R. Neueder, and G. Lauermann, Vapor pressures of non-aqueous electrolyte solutions. Part 1. Alkali metal salts in methanol, J. Solution Chem. 14 (1985) 621–633. [22] J. A. Rard, R. F. Platford, and K. S. Pitzer, Activity Coefficients in Electrolyte Solutions, CRC Press. Boca Raton, FL, 1991, pp. 209–277.
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SC
RI PT
[23] H. Uedaira, M. Ikura, H. Uedaira, Natural-abundance oxygen-17 magnetic relaxation in aqueous solutions of carbohydrates, Bull. Chem. Soc. Jpn. 62 (1989) 1-4. [24] M.A. Kabayama, D. Patterson, The thermodynamics of mutarotation of some sugars: II. Theoretical consideration, Can. J. Chem. 36 (1958) 563-573. [25] S.A. Galema, H. Hoiland, Stereochemical aspects of hydration of carbohydrates in aqueous solutions. 3. Density and ultrasound measurements, J. Phys. Chem. 95 (1991) 5321-5326. [26] F. Franks, Physical Chemistry of Small Carbohydrates-Equilibrium Solution Properties. Pure Appl. Chem. 59 (1987) 1189–1202. [27] Prausnitz, J. M.; Lichtenthaler, R. N.; de Azevedo, E. G. Molecular Thermodynamics of FluidPhase Equilibria; Pearson Education, 1998. [28] R. Kolhapurkar, K. Patil, Studies of Volumetric and Activity Behaviors of Binary and Ternary Aqueous Solutions Containing β-Cyclodextrin and Glucose, J. Mol. Liq. 178 (2013) 185–191. [29] J.J. Kozak, W.S. Knight, W. Kauzmann, Solute‐Solute Interactions in Aqueous Solutions, J. Chem. Phys. 48 (1968) 675–690.
13
ACCEPTED MANUSCRIPT Figure 1 Plot of the experimental osmotic coefficient, Φ, (1a) and water activity, aw, (1b) data of the investigated aqueous monosaccharides solutions as a function of molality, m / (mol.kg-1), of solutes at 308.15 K: ○, L (+)–Arabinose; ●, D (+)–Xylose; +, D (-)–Ribose; ◇, D (+)–Mannose; ▲, D (-)– Fructose; ×, D (+)– Galactose; △, D (+)–Glucose.
RI PT
Figure 2 Plot of the experimental osmotic coefficient, Φ, (2a) and water activity, aw, (2b) data of the investigated aqueous disaccharides solutions (as well as glucose and raffinose aqueous solutions for comparison with disaccharides) as a function of molality, m / (mol.kg-1), of solutes at 308.15 K: ○, Lactose; ●, Sucrose; +, Maltose; ◇, D (+)–Glucose; ▲, Raffinose.
SC
Figure 3 Plot of the experimental osmotic coefficient, Φ, (3a) and water activity, aw, (3b) data of the investigated aqueous polyols solutions as a function of molality, m / (mol.kg-1), of solutes at 308.15
M AN U
K: ○, Maltitol; ●, D (-)–Sorbitol; +, Xylitol; ◇, D (+)–Xylose; ▲, Maltose; ×, D (+)–Glucose.
Figure 4 Plot of the experimental osmotic coefficient, Φ, (4a) and solute activity coefficient, γ s( m ) , (4b) data of the investigated aqueous solutions as a function of solute molality, m / (mol.kg-1), at 308.15 K.
TE D
Figure 5 Plot of the excess molar Gibbs free energy, GmE , of the investigated aqueous solutions as a function of solute molality, m / (mol.kg-1), at 308.15 K.
AC C
EP
Figure 6 Plot of the comparison between our data (solid lines and filled marker) and literatures (dotted lines and empty marker) for osmotic coefficients of D (+)-Glucose aqueous solutions: ●, our data at 308.15 K; ○, ref [4] at 310.15 K; ◇, ref [4] at 298.15 K; △, ref [6] at 298.15 K; □, ref [5] at 298.15 K; -, ref [7] at 298.15 K. Figure 7 Plot of the comparison between our data at 308.15 K (solid lines and filled marker) and literatures at 298.15 K (dotted lines and empty marker) for water activities, aw, (7a) of Sucrose and Maltose aqueous solutions: ●, our data (Maltose); ▲, our data (Sucrose); ○, ref [12] (maltose); △, ref [6] (Sucrose); □, ref [8] (sucrose) and for osmotic coefficients, Φ, (7b) of Sorbitol and Glucose aqueous solutions: ▲, our data (D (+)-Glucose); ■, our data (Sorbitol); △, ref [7] (D (+)-Glucose); □, ref [7] (Sorbitol). Figure 8 Plot of the comparison between our data and literatures for osmotic coefficients of sorbitol (8a) and xylitol (8b) aqueous solutions: ●, our data at 308.15 K; ○, ref [14] at 308.15 K; ×, ref [15] at 308.15 K; ◇, ref [10] at 298.15 K; △, ref [7] at 298.15 K; □, ref [11] at 298.15 K; +, ref [14] at 298.15 K.
14
ACCEPTED MANUSCRIPT
58.44
Merck Acros Merck Merck Merck Merck Merck Merck Merck Merck Merck Alfa Aesar Merck Alfa Aesar
none none none none none none none none none none none none none none
Merck
EP AC C
Final mass fraction purity ≥ 0.99 ≥ 0.99 ≥ 0.99 ≥ 0.995 ≥ 0.98 ≥ 0.98 ≥ 0.99 ≥ 0.98 0.99 ≥ 0.98 ≥ 0.97 0.99 ≥ 0.99 0.97
SC
RI PT
Purification method
TE D
NaCl
Source
M AN U
Table 1 Specification of Chemical Samples 103⋅Molecular Chemical name weight (kg⋅mol-1) D (+) - Xylose 150.13 D (-) - Ribose 150.13 L (+) - Arabinose 150.13 D (+) - Glucose 180.16 D (+) - Galactose 180.16 D (+) - Mannose 180.16 D (-) - Fructose 180.16 Sucrose 342.29 Maltose monohydrate 360.32 Lactose monohydrate 360.32 Raffinose pentahydrate 594.52 Xylitol 152.15 D (-) - Sorbitol 182.17 Maltitol 344.32
was dried in an electrical oven at about 110 0C for 24 h prior to use
≥ 0.995
15
ACCEPTED MANUSCRIPT Table 2 Calibration Coefficients bi in equation 1.
b0
gain = 16, bridge voltage = 100% gain = 16, bridge voltage = 52.1%
-3
- 0.04102336
3.63567804 × 10
-3
b2 -4
- 1.46651770 × 10
-8
1.22600771 × 10
-11
7.88975520 × 10
-4
- 2.33960676 × 10
-7
8.61843277 × 10
-11
5.25320889 × 10
-3
- 1.06209327 × 10
M AN U TE D EP AC C
b3
3.18956224 × 10
SC
gain = 1, bridge voltage = 100%
1.04055427 × 10
b1
RI PT
mode of setting
-6
- 1.65155684 × 10
-10
16
ACCEPTED MANUSCRIPT Table 3 Experimental osmotic coefficient, Φ, water activity, aw, vapor pressure, p / (kPa) and solute activity coefficient, γ s(m) , data of the investigated aqueous solutions as a function of solute molality, m / (mol⋅kg-1), at 308.15 K m/
aw
Φ
p / (kPa)
-1
γ s(m)
0.9988
5.6252
0.9909
0.0332
0.9993
0.1355
0.9894
0.9976
5.6185
0.9832
0.0672
0.9973
0.2058
0.9874
0.9963
5.6111
0.9767
0.1346
0.9965
0.2784
0.9869
0.9951
5.6043
0.9713
0.2071
0.3372
0.9866
0.9940
5.5981
0.9677
0.2766
0.4237
0.9852
0.9925
5.5897
0.9634
0.3435
0.5011
0.9853
0.9911
5.5818
0.9605
0.5801
0.9850
0.9898
5.5744
0.6558
0.9853
0.9884
0.7393
0.9852
0.9870
0.8160
0.9857
0.9856
0.9059
0.9858
0.9840
1.0227
0.9859
0.9820
1.1649
0.9868
0.9795
1.3063
0.9870
1.6615
0.9881
2.9983
0.9994
5.6286
0.9981
0.9988
5.6252
0.9964
0.9976
5.6185
0.9934
SC
0.9970
0.9963
5.6111
0.9909
0.9956
0.9951
5.6043
0.9889
0.9951
0.9939
5.5976
0.9874
0.4151
0.9944
0.9926
5.5902
0.9861
0.9582
0.4952
0.9947
0.9912
5.5823
0.9850
5.5665
0.9565
0.5785
0.9949
0.9897
5.5739
0.9842
5.5586
0.9551
0.6498
0.9944
0.9884
5.5665
0.9836
TE D
M AN U
0.9950
0.9540
0.8204
0.9948
0.9854
5.5496
0.9825
5.5417
0.9531
0.9055
0.9945
0.9839
5.5411
0.9821
5.5304
0.9521
1.0411
0.9945
0.9815
5.5276
0.9814
5.5163
0.9512
1.1770
0.9944
0.9791
5.5140
0.9807
0.9770
5.5022
0.9504
1.3128
0.9942
0.9768
5.5010
0.9800
0.9709
5.4677
0.9487
1.6594
0.9950
0.9707
5.4666
0.9786
0.9919
0.9651
5.4350
0.9489
2.4020
1.0015
0.9576
5.3927
0.9844
0.9966
0.9589
5.4000
0.9524
3.2716
1.0159
0.9419
5.3041
1.0016
1.0019
0.9521
5.3616
0.9596
1.0074
0.9470
5.3329
0.9635
EP
5.5507
AC C
2.7220
γ s(m)
L (+) – Arabinose + water
0.0672
2.3380
p / (kPa)
(mol⋅kg )
D (+) - Xylose + water
1.9876
aw
Φ -1
RI PT
(mol⋅kg )
m/
Xylitol + water
D (-) - Ribose + water 0.0338
0.9992
0.9994
5.6286
0.9916
0.0672
0.9880
0.9988
5.6252
0.9841
0.0663
1.0022
0.9988
5.6252
1.0012
0.1353
0.9826
0.9976
5.6185
0.9707
0.1332
1.0021
0.9976
5.6185
1.0024
0.2041
0.9786
0.9964
5.6117
0.9597
0.2029
1.0016
0.9963
5.6111
1.0036
0.2789
0.9769
0.9951
5.6043
0.9499
17
ACCEPTED MANUSCRIPT 1.0023
0.9951
5.6043
1.0048
0.3505
0.9753
0.9939
5.5976
0.9424
0.3466
1.0028
0.9938
5.5970
1.0061
0.4242
0.9745
0.9926
5.5902
0.9362
0.4199
1.0037
0.9924
5.5891
1.0074
0.4990
0.9743
0.9913
5.5829
0.9312
0.4950
1.0046
0.9911
5.5818
1.0088
0.5801
0.9736
0.9899
5.5750
0.9270
0.5643
1.0050
0.9898
5.5744
1.0100
0.6538
0.9734
0.9886
5.5677
0.9240
0.6343
1.0053
0.9886
5.5677
1.0114
0.7165
0.9730
0.9875
5.5614
0.9219
0.7296
1.0059
0.9869
5.5581
1.0133
0.7426
0.9732
0.7920
1.0072
0.9857
5.5513
1.0146
0.8289
0.9730
0.8908
1.0085
0.9839
5.5411
1.0168
0.9054
0.9732
0.9999
1.0106
0.9820
5.5304
1.0193
1.0380
0.9735
1.1429
1.0125
0.9794
5.5157
1.0227
1.1830
1.2974
1.0147
0.9766
5.4999
1.0268
1.4531
1.4741
1.0166
0.9734
5.4819
1.0317
2.0274
1.0262
0.9632
5.4243
2.6463
1.0359
0.9518
3.2895
1.0423
4.4126
1.0478
5.5592
0.9212
0.9856
5.5507
0.9190
0.9843
5.5434
0.9173
0.9820
5.5304
0.9149
0.9735
0.9795
5.5163
0.9125
0.9745
0.9748
5.4898
0.9080
1.9881
0.9774
0.9656
5.4378
0.9007
1.0485
2.5940
0.9857
0.9550
5.3780
0.9061
5.3599
1.0673
3.2659
0.9944
0.9432
5.3114
0.9117
0.9401
5.2939
1.0834
0.9201
5.1811
1.1038
M AN U
TE D
0.9999
0.9990
0.1149
1.0009
0.9979
0.1727
1.0036
0.2306
1.0028
D (-) – Fructose + water
0.0559
0.9986
0.9990
5.6264
0.9978
0.1125
0.9958
0.9980
5.6207
0.9957
5.6264
1.0017
0.1714
0.9944
0.9969
5.6145
0.9938
5.6201
1.0035
0.2296
0.9949
0.9959
5.6089
0.9921
0.9969
5.6145
1.0052
0.2923
0.9947
0.9948
5.6026
0.9905
0.9958
5.6083
1.0070
0.3466
0.9945
0.9938
5.5970
0.9893
AC C
EP
0.0558
SC
0.9871
D (+) – Galactose + water
0.2878
RI PT
0.2718
1.0045
0.9948
5.6026
1.0086
0.4185
0.9946
0.9925
5.5897
0.9878
1.0057
0.9936
5.5959
1.0105
0.4792
0.9949
0.9914
5.5835
0.9868
1.0058
0.9926
5.5902
1.0121
0.5468
0.9947
0.9902
5.5767
0.9858
0.4829
1.0066
0.9913
5.5829
1.0140
0.6140
0.9951
0.9891
5.5705
0.9850
0.5526
1.0080
0.9900
5.5756
1.0158
0.6925
0.9951
0.9877
5.5626
0.9842
0.6174
1.0081
0.9888
5.5688
1.0174
0.7872
0.9955
0.9860
5.5530
0.9835
0.6818
1.0089
0.9877
5.5626
1.0190
0.9018
0.9950
0.9840
5.5417
0.9829
0.7847
1.0097
0.9858
5.5518
1.0214
1.0224
0.9947
0.9818
5.5293
0.9826
0.3548 0.4098
18
ACCEPTED MANUSCRIPT 1.0113
0.9838
5.5406
1.0239
1.1389
0.9949
0.9798
5.5180
0.9826
1.0093
1.0119
0.9818
5.5293
1.0264
1.2655
0.9949
0.9776
5.5056
0.9828
1.1379
1.0130
0.9794
5.5157
1.0293
1.7407
0.9972
0.9692
5.4582
0.9851
1.3084
1.0158
0.9763
5.4982
1.0333
2.4014
1.0057
0.9574
5.3916
0.9920
1.8502
1.0248
0.9664
5.4423
1.0503
2.9503
1.0142
0.9475
5.3357
1.0015
2.6098
1.0450
0.9521
5.3616
1.0844
3.6246
1.0266
0.9352
5.2663
1.0197
5.4239
1.0685
D (+) – Glucose + water 0.0557
1.0023
0.9990
5.6264
1.0021
0.1126
1.0050
0.9980
5.6207
1.0041
0.1128
0.9933
0.1685
1.0044
0.9970
5.6151
1.0059
0.2298
0.2236
1.0035
0.9960
5.6094
1.0076
0.3533
0.2913
1.0041
0.9947
5.6021
1.0095
0.4798
0.3539
1.0049
0.9936
5.5959
1.0111
0.4081
1.0057
0.9926
5.5902
0.4775
1.0059
0.9914
0.5382
1.0062
0.5708
RI PT
0.8958
0.9009
5.0727
1.0842
5.6207
0.9861
0.9890
0.9959
5.6089
0.9750
0.9840
0.9938
5.5970
0.9662
0.9828
0.9915
5.5840
0.9596
0.6097
0.9824
0.9893
5.5716
0.9548
1.0124
0.7659
0.9832
0.9865
5.5558
0.9510
5.5835
1.0141
0.9375
0.9836
0.9835
5.5389
0.9485
0.9903
5.5772
1.0155
1.1170
0.9842
0.9804
5.5214
0.9470
1.0077
0.9897
5.5739
1.0162
1.3041
0.9852
0.9771
5.5027
0.9463
0.6209
1.0075
0.9888
5.5688
1.0173
1.8290
0.9903
0.9679
5.4508
0.9461
0.6815
1.0085
0.9877
5.5626
1.0187
2.5437
0.9978
0.9553
5.3797
0.9515
0.7347
1.0086
0.9867
5.5569
1.0199
3.6589
1.0170
0.9352
5.2663
0.9727
0.7963
1.0087
0.9085
1.0102
M AN U
TE D
0.9856
5.5507
1.0213
0.9836
5.5394
1.0239
0.0296
0.9997
0.9995
5.6292
1.0070
AC C
1.0193
SC
0.9980
EP
D (+) – Mannose + water
Sucrose + water
1.0115
0.9816
5.5281
1.0267
0.0581
1.0007
0.9990
5.6264
1.0135
1.0139
0.9799
5.5185
1.0291
0.0904
1.0078
0.9984
5.6230
1.0205
1.0151
0.9780
5.5078
1.0322
0.1209
1.0130
0.9978
5.6196
1.0268
1.3226
1.0169
0.9761
5.4971
1.0355
0.1534
1.0169
0.9972
5.6162
1.0332
1.5688
1.0225
0.9715
5.4711
1.0442
0.1988
1.0193
0.9964
5.6117
1.0416
1.8406
1.0301
0.9664
5.4423
1.0555
0.2535
1.0253
0.9953
5.6055
1.0511
2.3864
1.0437
0.9561
5.3842
1.0825
0.3157
1.0283
0.9942
5.5993
1.0610
2.9452
1.0609
0.9453
5.3233
1.1129
0.3938
1.0319
0.9927
5.5908
1.0725
1.1093 1.2150
19
ACCEPTED MANUSCRIPT 3.6262
1.0783
0.9320
5.2482
1.1483
0.4770
1.0352
0.9911
5.5818
1.0838
4.8470
1.1102
0.9076
5.1105
1.2176
0.5567
1.0393
0.9896
5.5733
1.0940
0.5822
1.0405
0.9891
5.5705
1.0971
0.9979
0.9995
5.6292
1.0008
0.6480
1.0417
0.9879
5.5637
1.1051
0.0558
1.0008
0.9990
5.6264
1.0016
0.7265
1.0471
0.9864
5.5552
1.1145
0.1110
0.9992
0.9980
5.6207
1.0030
0.8492
1.0528
0.9840
5.5417
1.1293
0.1676
1.0032
0.9970
5.6151
1.0041
0.9710
1.0585
0.9817
5.5287
1.1446
0.2296
1.0022
0.9959
5.6089
1.0052
1.0875
1.0651
0.9793
5.5152
1.1601
0.2892
1.0035
0.9948
5.6026
1.0061
1.1856
1.0675
0.9775
5.5050
1.1742
0.3523
1.0028
0.9937
5.5964
1.0069
1.2747
0.4124
1.0037
0.9926
5.5902
1.0075
1.9957
0.4781
1.0033
0.9914
5.5835
1.0081
2.6794
0.5436
1.0028
0.9902
5.5767
1.0086
0.6109
1.0031
0.9890
5.5699
1.0090
0.6764
1.0033
0.9878
5.5631
1.0095
0.7778
1.0033
0.9860
5.5530
1.0102
0.8812
1.0035
0.9842
0.9996
1.0044
0.9821
1.1116
1.0056
0.9801
1.2843
1.0075
0.9770
1.7230
1.0129
2.3421
1.0272
3.6449
0.9756
5.4943
1.1878
1.1486
0.9595
5.4034
1.3297
1.2015
0.9437
5.3142
1.4916
3.4118
1.2484
0.9261
5.2149
1.6407
3.9268
1.2757
0.9137
5.1449
1.7530
TE D
M AN U
1.0741
Maltose monohydrate + water
0.0280
0.9905
0.9995
5.6292
1.0015
1.0110
0.0568
1.0036
0.9990
5.6264
1.0032
5.5310
1.0121
0.1006
0.9985
0.9982
5.6218
1.0060
5.5197
1.0134
0.1463
1.0034
0.9974
5.6173
1.0093
5.5022
1.0159
0.2069
1.0070
0.9963
5.6111
1.0141
0.9690
5.4570
1.0255
0.2737
1.0123
0.9950
5.6038
1.0197
0.9576
5.3927
1.0458
0.3055
1.0138
0.9944
5.6004
1.0225
1.0411
0.9461
5.3278
1.0691
0.3739
1.0173
0.9932
5.5936
1.0285
1.0572
0.9329
5.2533
1.0975
0.4474
1.0200
0.9918
5.5857
1.0351
0.5051
1.0218
0.9907
5.5795
1.0402
EP
5.5428
AC C
2.9559
RI PT
0.0278
SC
D (-) – Sorbitol + water
Lactose monohydrate + water
0.0279
0.9946
0.9995
5.6292
0.9975
0.5739
1.0236
0.9895
5.5727
1.0463
0.1155
1.0106
0.9979
5.6201
1.0076
0.6801
1.0270
0.9875
5.5614
1.0553
0.2049
1.0223
0.9962
5.6105
1.0315
0.8153
1.0304
0.9850
5.5473
1.0662
0.2572
1.0299
0.9952
5.6049
1.0471
0.9512
1.0363
0.9824
5.5327
1.0767
0.3590
1.0465
0.9933
5.5942
1.0761
1.1085
1.0429
0.9794
5.5157
1.0888
20
ACCEPTED MANUSCRIPT 0.4626
1.0575
0.9912
5.5823
1.1021
1.2732
1.0501
0.9762
5.4977
1.1022
0.5817
1.0645
0.9889
5.5693
1.1272
1.7770
1.0776
0.9661
5.4407
1.1586
0.6433
1.0665
0.9877
5.5626
1.1357
2.5813
1.1408
0.9483
5.3402
1.2858
Raffinose pentahydrate + water
Maltitol + water
1.0015
0.9994
5.6286
1.0068
0.0292
0.9903
0.9995
5.6292
1.0030
0.1059
1.0253
0.9980
5.6207
1.0378
0.1187
0.9976
0.9979
5.6201
1.0123
0.1837
1.0401
0.9966
5.6128
1.0782
0.2190
1.0116
0.9960
5.6094
1.0232
0.2667
1.0623
0.9949
5.6032
1.1195
0.3226
1.0186
0.9941
5.5987
1.0349
0.3581
1.0832
0.9930
5.5925
1.1689
0.4282
1.0276
0.9921
5.5874
1.0475
0.4515
1.1172
0.9910
5.5812
1.2370
0.5127
1.0308
0.9905
5.5784
1.0580
0.4902
1.1340
0.9900
5.5756
1.2712
0.5925
1.0322
0.9890
5.5699
1.0684
0.6205
1.1677
0.9870
5.5586
1.3640
0.7740
1.0489
0.9855
5.5502
1.0936
0.9158
1.0599
0.9827
5.5343
1.1150
1.0543
1.0665
0.9799
5.5185
1.1373
1.2607
1.0814
0.9757
5.4948
1.1734
1.9178
1.1510
0.9610
5.4119
1.3103
2.6448
1.2172
0.9437
5.3142
1.4894
3.5914
1.2724
0.9210
5.1861
1.6973
TE D
M AN U
SC
RI PT
0.0343
AC C
respectively.
EP
The uncertainty in m, Φ, aw and p was ±2·10-4 mol·kg-1, ±1·10-3, ±1·10-4 and ±1·10-3 kPa
21
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Table 4 Arrangements of the hydroxyl group substituent at C-2, C-3 and C-4 of the investigated carbohydrates Carbohydrate OH(2) OH(3) OH(4) D (+) - Xylose equatorial equatorial equatorial D (-) - Ribose equatorial axial equatorial L (+) - Arabinose equatorial equatorial axial D (+) - Glucose equatorial equatorial equatorial D (+) - Galactose equatorial equatorial axial D (+) - Mannose axial equatorial equatorial
22
ACCEPTED MANUSCRIPT Table 5 Parameters of equations (8) and (9), together with the standard deviations (σ). A2
A3
A4
A5
σ
arabinose
-0.029649
0.056041
-0.046525
0.017018
-0.002154
0.0004
ribose
-0.129756
0.215040
-0.155451
0.050534
-0.005947
0.0019
xylose
-0.073976
0.123956
-0.089892
0.029890
-0.003625
0.0010
Fructose
-0.020900
0.023522
-0.010230
0.002296
-0.000184
0.0012
galactose
0.015149
0.001193
-0.010875
0.008062
-0.001514
0.0005
glucose
0.019808
-0.020858
0.017022
-0.004480
0.000388
0.0009
mannose
-0.069783
0.095547
-0.056030
0.015449
-0.001572
0.0006
Lactose monohydrate
-0.080174
1.803325
-5.671610
7.771960
-4.081269
0.0022
maltose monohydrate
0.024829
0.077617
-0.117831
0.065921
-0.011698
0.0031
sucrose
0.121473
-0.146152
0.114475
Raffinose pentahydrate
0.036862
2.845706
-14.533289
xylitol
0.009091
-0.002815
0.005494
sorbitol
0.015471
-0.028548
0.023684
maltitol
0.050830
0.007881
0.008009
EP AC C
SC
RI PT
A1
-0.033626
0.003338
0.0026
30.372758
-21.539128
0.0019
-0.001961
0.000200
0.0005
-0.006781
0.000668
0.0009
-0.002857
0.000155
0.0045
M AN U
TE D
solute
23
ACCEPTED MANUSCRIPT Scheme 1 OH
D-Xylose
L-Arabinose
O
D-Ribose O
O
HO
HO HO
HO OH
OH
OH
OH
OH
OH
OH D-Galactose
OHOH
O
OH
OH O
O
HO HO
HO HO
HO OH
OH
OH
OH
CH2OH
Xylitol
D-Sorbitol
OH
OH
OH HO HO
OH
HO HO
M AN U
O
OH
SC
OH
D-Fructose
D-Mannose
RI PT
OH D-Glucose
OH
OH
OH
Sucrose CH2OH
OH
OH
CH2OH
Lactose
OH
O
HO HO
CH2OH
CH2OH OH
O
OH
O
O
HO
TE D
O
OH
CH2OH
O
OH
HO OH
CH2OH
OH
Maltose
O
HO HO
CH2OH
OH
Maltitol O
CH2OH
OH
O
O
OH
HO
HO
AC C
O
CH2OH
HO HO
EP
CH2OH
OH OH
OH OH OH
CH2OH HO
O OH
Raffinose
O O HO HO
CH2OH OH
O
OH
O CH2OH OH
ACCEPTED MANUSCRIPT
Figure 1b
Figure 1a
AC C
EP
TE D
M AN U
SC
RI PT
24
Figure 1b
ACCEPTED MANUSCRIPT
Figure 2a
AC C
EP
TE D
M AN U
SC
RI PT
25
Figure 2b
ACCEPTED MANUSCRIPT
Figure 3a
AC C
EP
TE D
M AN U
SC
RI PT
26
Figure 3b
ACCEPTED MANUSCRIPT
1.12 1.08 1.04
1.5 1.4 1.3 1.2 1.1
1.00 0.96 1
2
3
4 -1
m / mol.kg
Figure 4a
5
6
EP
0
TE D
1.0
AC C
Φ
1.16
1.6
raffinose lactose maltitol sucrose maltose glucose galactose xylitol sorbitol fructose arabinose xylose mannose ribose
SC
1.20
1.7
γs
1.24
1.8
M AN U
raffinose lactose maltitol sucrose maltose glucose galactose xylitol sorbitol fructose arabinose xylose mannose ribose
1.28
RI PT
27
0.9 0
1
2
3
4 -1
m / mol.kg
Figure 4b
5
6
ACCEPTED MANUSCRIPT
28
RI PT
50
SC
40
-1
M AN U
30 20
E
Gm / J.mol
raffinose lactose maltitol sucrose maltose glucose galactose xylitol sorbitol fructose arabinose xylose mannose ribose
TE D
10 0
EP
-10 1
2
AC C
0
3
4 -1
m / mol.kg
Figure 5
5
6
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
29
Figure 6
ACCEPTED MANUSCRIPT
Figure 7a
AC C
EP
TE D
M AN U
SC
RI PT
30
Figure 7b
ACCEPTED MANUSCRIPT
AC C
Figure 8a
EP
TE D
M AN U
SC
RI PT
31
Figure 8b
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
• VLE properties of carbohydrate aqueous solutions were studied • Several monosaccharides, disaccharides, trisaccharides and polyols were studied • Effect of carbohydrates stereochemistry on the VLE of their aqueous solutions • Effect of carbohydrates structure on the VLE of their aqueous solutions