Solubility of Xylose, Mannose, Maltose Monohydrate, and Trehalose

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Solubility of Xylose, Mannose, Maltose Monohydrate, and Trehalose Dihydrate in Ethanol−Water Solutions Xingchu Gong, Chuan Wang, Lei Zhang, and Haibin Qu* Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, P. R. China ABSTRACT: The solubilities of (2R,3S,4R)-2,3,4,5-tetrahydroxypentanal (xylose), (2R,3R,4R,5R)-2,3,5,6-tetrahydroxy-4-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyhexanal hydrate (maltose monohydrate), (2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxane-3,4,5-triol dihydrate (trehalose dihydrate), and (3S,4S,5S,6R)-6-(hydroxymethyl)oxane-2,3,4,5-tetrol (mannose) in the mixtures of ethanol and water from (278.2 to 298.2) K were determined. The solubilities of all the four saccharides in ethanol−water mixtures increased as equilibrium temperature increased. The solubilities of trehalose dihydrate, xylose, and mannose decreased as ethanol mass fraction in the mixed solvent increased. Maltose monohydrate solubility decreased when ethanol mass fraction in the mixed solvent was less than 0.9. The solubilities of xylose and mannose were predicted with A-UNIFAC, and the average relative deviations (ARD) values were less than 22 %. The solubilities of maltose monohydrate and trehalose dihydrate were calculated with the modified UNIQUAC model. New interaction parameters were calibrated. The ARD values for trehalose dihydrate solubility and maltose monohydrate solubility are 28.6 % and 17.9 %, respectively.

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INTRODUCTION Ethanol precipitation is a separation technology with many advantages, such as safe solvent, easy operation, and high removal for high polarity components, such as saccharides, proteins, and inorganic salts. Therefore, it is widely applied in the purification of water extract obtained from medicinal herbs.1 Saccharides are usually the main components in water extracts. However, they are not active constituents for these medicinal herbs at most occasions. The removal of saccharides helps to improve active constituent purity.2 Therefore, smaller drug dosage can be used. Saccharides can also decompose under the effects of acid, alkaline, or temperature. Some of the decomposition products, such as 5-hydroxymethylfurfural (5HMF), are harmful for persons, especially in Chinese medicine injections. Therefore, the removal of saccharides can also help to improve drug safety. Data on the solubility in ethanol−water solution of saccharides are important for the design and optimization of the ethanol precipitation process. The solubility data of Dglucose,3−6 D-fructose,6−8 and sucrose6,9,10 in ethanol−water solution are widely available in the literature. However, solubility data of other saccharides are limited.11,12 Activity coefficient models have been widely used to calculate the solubility of saccharides.13−16 Peres and Macedo proposed a modified UNIQUAC model17 and a modified UNIFAC model18 to calculate phase equilibrium in systems containing saccharides. Spiliotis and Tassios19 proposed the S-UNIFAC model, which was developed based on LLE-UNIFAC model,20 to describe phase equilibrium in saccharide solution. After that, Tsavas et al.21developed mS-UNIFAC model based on Lyngby modified UNIFAC model.22 In S-UNIFAC model and mS© 2012 American Chemical Society

UNIFAC model, the methylenehydroxyl groups were defined as a new main UNIFAC group. Ferreira et al.23 proposed AUNIFAC by introducing four new main groups of pyranose ring, furanose ring, hydroxyl group directly attached to the ring, and the osidic bond. Montanes et al.24 revised the interaction parameters of A-UNIFAC model with saccharide solubility in different alcohols. (2R,3S,4R)-2,3,4,5-Tetrahydroxypentanal (xylose), (2R,3R,4R,5R)-2,3,5,6-tetrahydroxy-4-[(2R,3R,4S,5S,6R)-3,4,5trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyhexanal (maltose), (2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-[(2R,3R,4S,5S,6R)3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxane-3,4,5triol (trehalose dihydrate), and (3S,4S,5S,6R)-6(hydroxymethyl)oxane-2,3,4,5-tetrol (mannose) are saccharides commonly existing in the water extracts of medicinal herbs. Their solubility data from (278.2 to 298.2) K were determined in this work. A-UNIFAC model and the modified UNIQUAC model were applied to calculate the solubility of these saccharides.

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MATERIALS AND METHODS Chemicals. Trehalose dihydrate (≥ 0.99, mass fraction purity) was purchased from Sinozyme Biotechnology Co., Ltd. (Nanning, China). Maltose monohydrate (≥ 0.99, mass fraction purity), xylose (≥ 0.99, mass fraction purity), and mannose (≥ 0.99, mass fraction purity) were purchased from Received: August 7, 2012 Accepted: October 17, 2012 Published: October 24, 2012 3264

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Sinopharm Chemical Reagent Co., Ltd. (Beijing, China). Ethanol (≥ 0.997, mass fraction purity) was purchased from Shanghai Lingfeng Chemical Reagent Co., Ltd. (Shanghai, China). All chemicals were used as received. Deionized water was produced by a Milli-Q academic water purification system (Milford, MA, USA). Table 1 lists a summary of chemicals used in this work and their applications.

Table 2. Solubility of Xylose in Ethanol−Water Mixtures (Grams per Gram of Solution) in Various Mass Fractions of Ethanol (w(ethanol)) in Ethanol + Water Mixtures at Atmospheric Pressure and Different Temperatures (T), Together with Error Limits Using the 95 % Confidence Levela T/K w(ethanol)

Table 1. Purity of Chemicals Used in This Study and Their Applications material

purity (mass fraction) ≥ 0.99

trehalose dihydrate maltose monohydrate xylose

≥ 0.99

mannose

≥ 0.99

ethanol

≥ 0.997

water

ultra purea

a

≥ 0.99

source

application

Sinozyme Biotechnology Co., Ltd. Sinopharm Chemical Reagent Co., Ltd. Sinopharm Chemical Reagent Co., Ltd. Sinopharm Chemical Reagent Co., Ltd. Shanghai Lingfeng Chemical Reagent Co., Ltd. lab made

solute

0.000 0.200 0.350 0.500 0.600 0.700 0.800 0.900 1.000

solute solute solute

a

solvent

278.2 0.5110 0.4078 0.3154 0.2594 0.1798 0.1196 0.0577 0.0202 0.0051

± ± ± ± ± ± ± ± ±

0.0069 0.0050 0.0040 0.0042 0.0005 0.0008 0.0003 0.0004 0.0001

288.2 0.5288 0.4576 0.3665 0.2956 0.2019 0.1374 0.0692 0.0255 0.0064

± ± ± ± ± ± ± ± ±

0.0198 0.0247 0.0089 0.0086 0.0034 0.0019 0.0011 0.0011 0.0001

298.2 0.5680 0.5082 0.4428 0.3234 0.2410 0.1583 0.0844 0.0306 0.0076

± ± ± ± ± ± ± ± ±

0.0094 0.0025 0.0144 0.0118 0.0030 0.0077 0.0008 0.0004 0.0001

Standard uncertainties u are u(T) = 0.1 K and u(w(ethanol)) = 0.002.

Table 3. Solubility of Mannose in Ethanol−Water Mixtures (Grams per Gram of Solution) in Various Mass Fractions of Ethanol (w(ethanol)) in Ethanol + Water Mixtures at Atmospheric Pressure and Different Temperatures (T), Together with Error Limits Using the 95 % Confidence Levela

solvent

Resistivity > 18.2 MΩ·cm at 25 °C.

Procedures. The solubilities of maltose monohydrate, trehalose dihydrate, xylose, and mannose were determined using the same isothermal method described in previous work.6,12 Ethanol−water mixtures with different mass fraction of ethanol were loaded in different jacketed glass cells. Each mixture was obtained by weighing the proper amount of solvent at 0.1 mg precision. Then, excess solute was placed into cells, and these mixtures were magnetically stirred for at least 24 h to achieve saturation conditions. Temperature was controlled by a thermostat water bath (THD-1008W, Ningbo Tianheng Instrument Factory). The mixtures were allowed to settle for at least 5 days at designed temperature to reach solid− liquid equilibrium. From each equilibrium cell, samples of saturated solutions were withdrawn using pipettes and quickly filtered through a fiberglass filter. Analytical Methods. The solubility of saccharides was determined by gravimetric method.11 Samples of known weight were collected to evaporate. The drying process had two steps: first, the samples were left to slowly evaporate at ambient conditions to remove most of ethanol. Then, they were dried in a vacuum oven (DZF-6050, Shanghai Jing Hong Laboratory Instrument Co., Ltd.) heated at 60 °C until no mass change was observed and weighed to get the content of saccharides. All the experiments were repeated three times.

T/K w(ethanol) 0.000 0.350 0.500 0.600 0.700 0.800 0.900 1.000 a

278.2 0.7450 0.6337 0.5186 0.4593 0.3244 0.1583 0.0593 0.0028

± ± ± ± ± ± ± ±

0.0127 0.0137 0.0109 0.0087 0.0095 0.0049 0.0018 0.0005

288.2 0.7653 0.6596 0.5668 0.4862 0.3509 0.1713 0.0642 0.0040

± ± ± ± ± ± ± ±

0.0030 0.0096 0.0027 0.0068 0.0024 0.0030 0.0002 0.0001

298.2 0.7763 0.6860 0.6030 0.5196 0.3756 0.1814 0.0706 0.0056

± ± ± ± ± ± ± ±

0.0054 0.0042 0.0033 0.0127 0.0104 0.0038 0.0024 0.0001

Standard uncertainties u are u(T) = 0.1 K and u(w(ethanol)) = 0.002.

Table 4. Solubility of Maltose Monohydrate in Ethanol− Water Mixtures (Grams per Gram of Solution) in Various Mass Fractions of Ethanol (w(ethanol)) in Ethanol + Water Mixtures at Atmospheric Pressure and Different Temperatures (T), Together with Error Limits Using the 95 % Confidence Levela T/K w(ethanol)

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0.000 0.500 0.600 0.700 0.800 0.900 1.000

RESULTS AND DISCUSSION The experimental data of xylose, mannose, maltose monohydrate, and trehalose dihydrate in the mixtures of ethanol and water from (278.2 to 298.2) K are listed in Tables 2 to 5, respectively. The tables include ethanol mass fraction in saccharide-free solution (w(ethanol)) versus the solubility in mass fraction. In Table 2, the solubility of xylose increased with the increase of water mass fraction in saccharide-free solution. Xylose solubility also increased as equilibrium temperature increases. The experimental data of mannose solubility are shown in Table 3. Mannose solubility decreased as w(ethanol) increased or equilibrium temperature decreased. In Table 4, when w(ethanol) value was less than 0.9, the solubility of

a

278.2 0.4106 0.1069 0.0552 0.0298 0.0123 0.0039 0.0103

± ± ± ± ± ± ±

0.0059 0.0044 0.0008 0.0007 0.0005 0.0004 0.0003

288.2 0.4424 0.1315 0.0679 0.0372 0.0166 0.0045 0.0108

± ± ± ± ± ± ±

0.0070 0.0062 0.0003 0.0003 0.0001 0.0002 0.0005

298.2 0.4792 0.1630 0.0791 0.0474 0.0233 0.0056 0.0118

± ± ± ± ± ± ±

0.0373 0.0008 0.0010 0.0003 0.0005 0.0004 0.0001

Standard uncertainties u are u(T) = 0.1 K and u(w(ethanol)) = 0.002.

maltose monohydrate decreased as w(ethanol) increased. Maltose monohydrate solubility in pure ethanol was a little larger than that in mixed ethanol−water solution with ethanol mass fraction of 0.9, which is in agreement with Bouchard et al.’s results.11 A probable explanation is that the crystal form of 3265

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maltose monohydrate changed when w(ethanol) is high.25 When equilibrium temperature increased, maltose monohydrate solubility increased. In Table 5, the solubility of trehalose

association group density, association strength, and UNIQUAC molecule volume.23 Group division is shown in Table 7.23 Table 7. Group Division for Xylose, Mannose, Water, and Ethanol23

Table 5. Solubility of Trehalose Dihydrate in Ethanol−Water Mixtures (Grams per Gram of Solution) in Various Mass Fractions of Ethanol (w(ethanol)) in Ethanol + Water Mixtures at Atmospheric Pressure and Different Temperatures (T), Together with Error Limits Using the 95 % Confidence Levela T/K w(ethanol) 0.000 0.200 0.350 0.500 0.600 0.700 0.800 0.900 1.000 a

278.2 0.3581 0.1853 0.1024 0.0602 0.0339 0.0133 0.0033 0.0007 0.0001

± ± ± ± ± ± ± ± ±

288.2

0.0057 0.0044 0.0014 0.0018 0.0001 0.0001 0.0004 0.0001 0.0001

0.4260 0.2632 0.1500 0.0921 0.0454 0.0182 0.0047 0.0011 0.0002

± ± ± ± ± ± ± ± ±

0.0094 0.0049 0.0009 0.0033 0.0022 0.0002 0.0001 0.0001 0.0001

298.2 0.4920 0.3662 0.2400 0.1257 0.0624 0.0257 0.0075 0.0017 0.0003

± ± ± ± ± ± ± ± ±

0.0178 0.0045 0.0011 0.0052 0.0058 0.0003 0.0003 0.0008 0.0001

group

xylose

mannose

water

ethanol

PYR1 PYR2 CH3 CH2 OH OHring H2O

0 1 0 0 0 4 0

1 0 0 1 0 5 0

0 0 0 0 0 0 1

0 0 1 1 1 0 0

Group interaction parameters, group volume parameters, and group area parameters were taken from the literature.23 The comparisons between the experimental data and the prediction results of xylose and mannose are shown in Figures 1 and 2, respectively. Gabas et al.’s27 results are also plotted in Figures 1 and 2 for comparison.

Standard uncertainties u are u(T) = 0.1 K and u(w(ethanol)) = 0.002.

dihydrate increased as w(ethanol) value decreased or equilibrium temperature increased. These results indicate that the addition of ethanol and refrigeration can contribute to remove more saccharides in the ethanol precipitation process. The equation adopted to calculate the solubility of xylose and mannose in mixed solvent is shown below:23 ln(γx) = − +

ΔfusH * ⎛ T ⎞ ΔCp ⎛ Tfus − T ⎞ ⎜ ⎟ ⎜1 − ⎟+ ⎠ RT ⎝ Tfus ⎠ R ⎝ T ΔCp ⎛ T ⎞ ln⎜ ⎟ R ⎝ Tfus ⎠

Figure 1. Comparison between experimental values with the prediction results of xylose solubility by A-UNIFAC model: □, experimental data at 278.2 K; ○, experimental data at 288.2 K; △, experimental data at 298.2 K; ●, experimental data at 298.2 K reported by Gabas et al.;27 ---, predicted values at 278.2 K; , predicted values at 288.2 K; ···, predicted values at 298.2 K.

(1)

where x is the mole fraction of the saccharide; γ is the saccharide activity coefficient; Tfus is the melting temperature; ΔfusH* is the enthalpy of fusion; ΔCp is the difference between the heat capacities of the pure liquid and the pure solid saccharides; R is the gas constant. Tfus, ΔCp, and ΔfusH* are taken from literature23 and listed in Table 6. Activity coefficient Table 6. Melting Temperature (Tfus), Enthalpy of Fusion (ΔfusH*), and Heat Capacity Difference (ΔCp) of Saccharides23 saccharide

Tfus/K

ΔfusH*/J·mol−1

ΔCp/J·mol−1·K−1

xylose mannose trehalose dihydrate maltose monohydrate

423.15 407.15 368.15 379.15

31650 24687 48048 45400

120.0 120.0 241 231

of component i (γi) was calculated with A-UNIFAC model, in which an associative term was introduced.23 γi = γicombγi resγiassoc

(2) Figure 2. Comparison between experimental values with the prediction results of mannose solubility by A-UNIFAC model: □, experimental data at 278.2 K; ○, experimental data at 288.2 K; △, experimental data at 298.2 K; ●, experimental data at 298.2 K reported by Gabas et al.;27 ---, predicted values at 278.2 K; , predicted values at 288.2 K; ···, predicted values at 298.2 K.

where superscripts comb, res, and assoc refer to combinatorial contribution, residual contribution, and associative contribution, respectively. The calculations of γicomb and γires were described in Fredenslund et al.'s work.26 γiassoc is a function of the number of associating groups in component i, the 3266

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Table 8. Representation of Experimental Data saccharide

model

T/K

w(ethanol)

data points

results type

AAD (%)

ARD (%)

xylose mannose maltose monohydrate

A-UNIFAC A-UNIFAC modified UNIQUAC

trehalose dihydrate

modified UNIQUAC

278.2−298.2 278.2−298.2 278.2−298.2 310 298.15−348.15 272.4−369.7 278.2−298.2 310 298.15−358.15 283.2−313.2

0−1 0−1 0−1 0−1 0 0 0−1 0−1 0 0

27 24 21 10 6 18 27 10 7 4

prediction prediction correlation correlation correlation correlation correlation correlation correlation correlation

2.94 1.82 1.58 0.80 2.59 5.56 1.91 1.49 11.3 15.6

20.4 21.6 17.9 14.9 4.16 15.4 28.6 34.4 16.5 28.6

The average absolute deviations (AAD) and average relative deviations (ARD) were both calculated using the following equations: AAD =

∑n |Snexp − Sncalc| NDP ∑n

ARD =

Snexp − Sncalc Snexp

NDP

× 100%

this this this 11 15 28 this 11 15 29

work work work

work

Table 9. Interaction Parameters of the Modified UNIQUAC Model

(3) a

× 100%

data source

i\j

trehalose

maltose

water

ethanol

trehalose maltose water ethanol

0 0 −172.70 702.48

0 0 95.611 −25.703

295.92 −51.555 0 249.06a

−138.34 337.07 −132.51a 0

From Macedo and Peres.7

(4)

where S represents the solubility of saccharides; superscripts calc and exp mean calculated values and experimental data, respectively; NDP are the number of experimental data points. The AAD and ARD values are listed in Table 8. Because the prediction results showed relatively larger deviations when w(ethanol) is smaller than 0.5, the AAD value for xylose solubility was larger than that of mannose solubility. The ARD values for xylose and mannose are less than 22 %. The solubility of maltose monohydrate and trehalose dihydrate was calculated with eq 5.23 ln(γ1x1) + nh ln(γ2x 2) =− +

Figure 3. Comparison between experimental values with the correlation results of maltose monohydrate solubility by the modified UNIQUAC model: □, experimental data at 278.2 K; ○, experimental data at 288.2 K; △, experimental data at 298.2 K; ●, experimental data at 310 K reported by Bouchard et al.;11 ---, calculated values at 278.2 K; , calculated values at 288.2 K; ···, calculated values at 298.2 K; -·-, calculated values at 310 K.

ΔfusH * ⎛ T ⎞ ΔCp ⎛ Tfus − T ⎞ ⎜ ⎟ ⎜1 − ⎟+ ⎠ RT ⎝ Tfus ⎠ R ⎝ T ⎛ T ⎞ ⎞ ⎛ 1 ln⎜ γ1(Tfus)⎟ ⎟ + ln⎜ R ⎠ ⎝ 1 + nh ⎝ Tfus ⎠

ΔCp

⎞ ⎛ nh γ2(Tfus)⎟ + nh ln⎜ ⎠ ⎝ 1 + nh

Bouchard et al.’s11 results are also plotted for comparison. The AAD and ARD values for maltose monohydrate solubility are shown in Table 8. The ARD value is less than 18 %, which indicates that satisfactory prediction results are obtained. A total of 48 data points were used to calibrate interaction parameters for the solubility of trehalose. ΔCp, Tfus, and ΔfusH* were taken from ref 23, as seen in Table 6. Calibrated interaction parameters are also listed in Table 9. Figure 4 shows the correlation results of trehalose dihydrate solubility. For the data determined in this work, the correlation results show large deviations when w(ethanol) value is 0.9. Though the AAD value is less than 2 %, the ARD value is larger than 28 %.

(5)

where x1 is the saccharide mole fraction in the liquid phase; γ1 is the activity coefficient of saccharide; x2 is the water mole fraction; γ2 is the activity coefficient of water; and nh is the number of water molecules per saccharide molecule in the solid phase. ΔCp, Tfus, and ΔfusH* were taken from the literature23 and listed in Table 6. A-UNIFAC model, S-UNIFAC model, and mS-UNIFAC model were used to calculate γ1 and γ2. However, the results were disappointing. Therefore, activity coefficients of maltose, trehalose, water, and ethanol were calculated with the modified UNIQUAC model.17 The rk and qk of maltose or trehalose were set as 14.5496 and 13.764, respectively, which is the same as those of sucrose.7 The interaction parameters were calibrated by minimizing the ARD value. A total of 55 data points were applied in the calibration for maltose monohydrate solubility, as seen in Table 8. The calibrated interaction parameters are listed in Table 9. Figure 3 shows the correlation results of maltose monohydrate solubility.

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CONCLUSIONS The solubility data of xylose, mannose, maltose monohydrate, and trehalose dihydrate in the mixtures of ethanol and water from (278.2 to 298.2) K were determined. The solubilities of all the four saccharides increased as equilibrium temperature increased. When w(ethanol) value increased, the solubilities of 3267

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(6) Gong, X. C.; Wang, S. S.; Qu, H. B. Solid−liquid equilibria of Dglucose, D-fructose and sucrose in the mixture of ethanol and water from 273.2 to 293.2 K. Chin. J. Chem. Eng. 2011, 19, 217−222. (7) Macedo, E. A.; Peres, A. M. Thermodynamics of ternary mixtures containing sugars. SLE of D-fructose in pure and mixed solvents. Comparison between modified UNIQUAC and modified UNIFAC. Ind. Eng. Chem. Res. 2001, 40, 4633−4640. (8) Flood, A. E.; Addai-Mensah, J.; Johns, M. R.; White, E. T. Refractive index, viscosity, density, and solubility in the system fructose + ethanol + water at 30, 40, and 50 °C. J. Chem. Eng. Data 1996, 41, 418−421. (9) Peres, A. M.; Macedo, E. A. Phase equilibria of D-glucose and sucrose in mixed solvent mixtures: comparison of UNIQUAC-based models. Carbohyd. Res. 1997, 303, 135−151. (10) Tsavas, P.; Polydorou, S.; Voutsas, E. C.; Magoulas, K. G.; Naraghi, K.; Halling, P. J. Sucrose solubility in mixtures of water, alcohol, ester, and acid. J. Chem. Eng. Data 2002, 47, 513−517. (11) Bouchard, A.; Hofland, G. W.; Witkamp, G. J. Properties of sugar, polyol, and polysaccharide water−ethanol solutions. J. Chem. Eng. Data 2007, 52, 1838−1842. (12) Zhang, L.; Gong, X. C.; Wang, Y. F.; Qu, H. B. Solubilities of protocatechuic aldehyde, caffeic acid, D-galactose, and D-raffinose pentahydrate in ethanol−water solutions. J. Chem. Eng. Data 2012, 57, 2018−2022. (13) Gabas, N.; Laguerie, C. Predictions with UNIFAC of liquid solid-phase diagrams: application to water−sucrose−glucose, water− sucrose−fructose and water−xylose−mannose. J. Cryst. Growth 1993, 128, 1245−1249. (14) Catte, M.; Dussap, C. G.; Gros, J. B. A physical−chemical unifac model for aqueous-solutions of sugars. Fluid Phase Equilib. 1995, 105, 1−25. (15) Jonsdottir, S. O.; Cooke, S. A.; Macedo, E. A. Modeling and measurements of solid−liquid and vapor−liquid equilibria of polyols and carbohydrates in aqueous solution. Carbohyd. Res. 2002, 337, 1563−1571. (16) Jonsdottir, S. O.; Rasmussen, P. Phase equilibria of carbohydrates in polar solvents. Fluid Phase Equilib. 1999, 160, 411−418. (17) Peres, A. M.; Macedo, E. A. Thermodynamic properties of sugars in aqueous solutions: correlation and prediction using a modified UNIQUAC model. Fluid Phase Equilib. 1996, 123, 71−95. (18) Peres, A. M.; Macedo, E. A. A modified UNIFAC model for the calculation of thermodynamic properties of aqueous and non-aqueous solutions containing sugars. Fluid Phase Equilib. 1997, 139, 47−74. (19) Spiliotis, N.; Tassios, D. A UNIFAC model for phase equilibrium calculations in aqueous and nonaqueous sugar solutions. Fluid Phase Equilib. 2000, 173, 39−55. (20) Magnussen, T.; Rasmussen, P.; Fredenslund, A. UNIFAC parameter table for prediction of liquid−liquid equilibria. Ind. Eng. Chem. Process Des. Dev. 1981, 20, 331−339. (21) Tsavas, P.; Voutsas, E.; Magoulas, K.; Tassios, D. Phase equilibrium calculations in aqueous and nonaqueous mixtures of sugars and sugar derivatives with a group-contribution model. Ind. Eng. Chem. Res. 2004, 43, 8391−8399. (22) Larsen, B. L.; Rasmussen, P.; Fredenslund, A. A modified UNIFAC group-contribution model for prediction of phase-equilibria and heats of mixing. Ind. Eng. Chem. Res. 1987, 26, 2274−2286. (23) Ferreira, O.; Brignole, E. A.; Macedo, E. A. Phase equilibria in sugar solutions using the A-UNIFAC model. Ind. Eng. Chem. Res. 2003, 42, 6212−6222. (24) Montanes, F.; Olano, A.; Ibanez, E.; Fornari, T. Modeling solubilities of sugars in alcohols based on original experimental data. AIChE J. 2007, 53, 2411−2418. (25) Verhoeven, N.; Neoh, T. L.; Ohashi, T.; Furuta, T.; Kurozumi, S.; Yoshii, H. Formation of a new crystalline form of anhydrous βmaltose by ethanol-mediated crystal transformation. Carbohyd. Res. 2012, 351, 74−80.

Figure 4. Comparison between experimental values with the correlation results of trehalose dihydrate solubility by the modified UNIQUAC model: □, experimental data at 278.2 K; ○, experimental data at 288.2 K; △, experimental data at 298.2 K; ●, experimental data at 310 K reported by Bouchard et al.;11 ---, calculated values at 278.2 K; , calculated values at 288.2 K; ···, calculated values at 298.2 K; -·-, calculated values at 310 K.

xylose, mannose, and trehalose dihydrate decreased. For maltose monohydrate, the solubility in pure ethanol was a little larger than that in mixed solvent with w(ethanol) of 0.9. A-UNIFAC model was used to predict the solubility of xylose and mannose. The ARD values are less than 22 %. The modified UNIQUAC model was applied to calculate the solubility of maltose monohydrate and trehalose dihydrate. New interaction parameters were calibrated. The ARD values for maltose monohydrate solubility and trehalose dihydrate solubility are 17.9 % and 28.6 %, respectively.

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AUTHOR INFORMATION

Corresponding Author

*Tel: +86 571 88208428. Fax: +86 571 88208428. E-mail: [email protected]. Funding

This work was financially supported by Zhejiang Provincial Natural Science Foundation of China (LQ12H29004), Zhejiang Provincial Education Department Research Program (Y200907556), and Public Service Technology Research and Social Development Project of Science Technology, Department of Zhejiang, Province of China (2011C23095). Notes

The authors declare no competing financial interest.

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REFERENCES

(1) Koh, G. Y.; Chou, G.; Liu, Z. Purification of a water extract of Chinese sweet tea plant (Rubus suavissimus S. Lee) by alcohol precipitation. J. Agric. Food Chem. 2009, 57, 5000−5006. (2) Gong, X. C.; Wang, S. S.; Qu, H. B. Comparison of two separation technologies applied in the manufacture of botanical injections: second ethanol precipitation and solvent extraction. Ind. Eng. Chem. Res. 2011, 50, 7542−7548. (3) Peres, A. M.; Macedo, E. A. Measurement and modeling of solubilities of D-glucose in water/alcohol and alcohol/alcohol systems. Ind. Eng. Chem. Res. 1997, 36, 2816−2820. (4) Alves, L. A.; Almeida e Silva, J. B.; Giulietti, M. Solubility of Dglucose in water and ethanol/water mixtures. J. Chem. Eng. Data 2007, 52, 2166−2170. (5) Flood, A. E.; Puagsa, S. Refractive index, viscosity, and solubility at 30 °C, and density at 25 °C for the system fructose + glucose + ethanol + water. J. Chem. Eng. Data 2000, 45, 902−907. 3268

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Journal of Chemical & Engineering Data

Article

(26) Fredenslund, A.; Jones, R. L.; Prausnitz, J. M. Groupcontribution estimation of activity coefficients in nonideal liquid mixtures. AIChE J. 1975, 21, 1086−1099. (27) Gabas, N.; Carlllon, T.; Hlqully, N. Solubilities of D-xylose and D-mannose in water−ethanol mixtures at 25 °C. J. Chem. Eng. Data 1988, 33, 128−130. (28) Stephen, H.; Stephen, T.; Silcock, H. L. Solubilities of Inorganic and Organic Compounds; Pergamon Press: New York, 1963. (29) Lammert, A. M.; Schmidt, S. J.; Day, G. A. Water activity and solubility of trehalose. Food Chem. 1998, 61, 139−144.

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