Article pubs.acs.org/jced
Solubility Determination and Correlation of (2R,3S,4S,5S)‑6(Hydroxymethyl)-tetrahydro‑2H‑pyran-2,3,4, 5‑tetraol in Fatty Alcohol Yongzhao Zhang,†,‡ Xia Guo,§ and Jianbing Ji*,† †
College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014, People’s Republic of China ‡ Hangzhou Vocational & Technical College, Hangzhou 310018, People’s Republic of China § Zhejiang Zanyu Technology Co., Ltd., Hangzhou 310009, People’s Republic of China S Supporting Information *
ABSTRACT: (2R,3S,4S,5S)-6-(Hydroxymethyl)-tetrahydro-2H-pyran2,3,4,5-tetraol (D-glucose) solubility in 1-dodecanol, 1-decanol, and 1octanol from 343.15 K to 393.15 K was determined, respectively. The solubility of D-glucose increased with an increase in temperature and decreased with the increase of fatty alcohol chain length. The modified UNIQUAC model, S-UNIFAC model, and mS-UNIFAC model were applied to predict the solubility data; the interaction parameters were determined. Of the three models, the modified UNIQUAC model showed better prediction accuracy.
1. INTRODUCTION As a nonionic surfactant, alkyl polyglucosides (APGs) are by far the most important sugar-based surfactant. Chemically, alkyl polyglucosides are acetates, which consist of a hydrophobic alkyl residue derived from a fatty alcohol and a hydrophilic saccharide structure derived from (2R,3S,4S,5S)-6-(hydroxymethyl)-tetrahydro-2H-pyran-2,3,4,5-tetraol (D-glucose), linked through a glycosidic bond.1 The wide applications of APGs to daily chemical industry, agriculture, and biochemical engineering are based on the special properties of alkyl polyglucosides, including their compatibility and synergistic effects when they are combined with many other surfactants and ingredients of surfactant-based formulations. This combined with their low environmental impact, their amazingly economical cost/ performance ratio, and the high quality standard already achieved has explained the current interest in alkyl polyglucosides.2−5 Hence, there is a good chance that alkyl polyglucosides will play a major role alongside the frequently used traditional surfactants. APGs can be produced with one-step or two-step method.6 In the one-step method, the D-glucose reacts with an excess of fatty alcohol to yield monoglucoside, along with smaller amounts of di-, tri-, and higher oligomeric glucosides. The reaction between 7 D-glucose and fatty alcohol follows a liquid mechanism. The Dglucose first dissolves in fatty alcohol. The dissolved D-glucose is reacted with fatty alcohol. Therefore the solubility data of Dglucose in fatty alcohol is valuable for the reaction kinetics study of the glycosylation reaction between D-glucose and fatty alcohol. Some solubility data of D-glucose in a mixture of water, ethanol, © 2014 American Chemical Society
and methanol at low temperature (usually under 333.15 K) is available in the literature. However, very few solubility data in fatty alcohol at higher temperature (above 343.15 K) is available. UNIFAC model and UNIQUAC model are widely used in the correlation and prediction of solubility.8−12 Peres and Macedo developed a modified UNIQUAC model to correlate and predict the solubility of sugars.13 Spiliotis and Tassios presented a groupcontribution model (the so-called S-UNIFAC model) to calculate the phase equilibrium of sugar in aqueous and nonaqueous solutions.14 Later, Tsavas et al. developed the mSUNIFAC model, which was based on the modified UNIFAC model of Larsen et al.15,16 For the S-UNIFAC model and mSUNIFAC model, one new UNIFAC group, CHOHsug, was introduced to describe all monosaccharides. Data used in the estimation of interaction parameters were determined at ambient temperature or higher temperature. However, the validity of the three models stated above for the fatty alcohol system at higher temperature is not yet illustrated. In this work, the solubility of D-glucose in 1-dodecanol, 1decanol, and 1-octanol was determined from 343.15 K to 393.15 K. The solubility data was correlated with the modified UNIQUAC model, S-UNIFAC model, and mS-UNIFAC model, respectively, the interaction parameters were determined, and the prediction accuracy for the three models was compared. Received: February 25, 2014 Accepted: May 10, 2014 Published: May 20, 2014 2040
dx.doi.org/10.1021/je4011097 | J. Chem. Eng. Data 2014, 59, 2040−2044
Journal of Chemical & Engineering Data
Article
2. EXPERIMENTAL SECTION 2.1. Chemicals. All chemicals were used without any further purification. The specifications for chemicals used are shown in Table 1.
the saturated glucose solution (about 0.5 g), namely, the clear upper portion of the solution was transferred through a 5 mL syringe into a 15 mL cuvette. The syringe wall was washed with dimethyl sulfoxide at least four times to remove the crystallized solute to the cuvette. The solution in the cuvette is diluted immediately with about 15 mL of dimethyl sulfoxide. The diluted sample was analyzed by gas chromatography stated above. All the experiments were repeated at least three times.
Table 1. Specifications for Chemicals Used chemical name D-glucose
1-dodecanol 1-decanol 1-octanol chlorotrimethylsilane hexamethyl disilylamine dimethyl sulfoxide
source
mass fraction purity
Aladdin Aladdin Aladdin Aladdin Aladdin Aladdin Tianjin Kemiou (China)
0.99 0.98 0.98 0.98 0.98 0.98 0.97
3. RESULTS AND DISCUSSION The experimentally determined solubility data in fatty alcohol (1dodecanol, 1-decanol and 1-octanol) at different temperatures is listed in Table 2. The solubility of D-glucose in different fatty Table 2. Experimental Mole Fraction Solubility x of D-Glucose in Fatty Alcohol at Temperature T and Pressure p = 0.1 MPaa 1-dodecanol
2.2. Analysis Technique. The analysis method for the alkyl polyglucosides system with gas chromatography was described by Spilker.18 D-Glucose could not be analyzed with gas chromatography directly because of its high gasification temperature. Sample must be derivatized before analysis. In the derivation process, the reactive hydrogen atoms of D-glucose were replaced by low polarity groups, and the gasification temperature of D-glucose decreased. In this paper, an Agilent 7820 gas chromatograph with a HP-5 capillary chromatographic column, FID detector, and Ezchrome chemstation was used to determine the amount of D-glucose in the sample. Temperature programming was adopted: From 0 to 120 s, the temperature was maintained at 353.15 K. Then, the temperature was raised to 583.15 K linearly with a speed of 8 K/min. Finally, the temperature was held at 583.15 K for 300 s. Hexamethyldisilazane (0.2 mL) and chlorotrimethylsilane (0.1 mL) were added to the sample (0.3 mL). This mixture was shaken violently for 60 s, and allowed to stand for 300 s. The supernatant was sampled for analysis. Since the use of more hexamethyldisilazane and chlorotrimethylsilane had no effect on the analysis results in the concentration range described in the paper, the content of them could ensure the complete derivation of D-glucose. In the analysis technique, the amount of D-glucose and fatty alcohol in standard was noted as mi and mc, the response signal was noted as Ai and Ac respectively. According to the principle of gas chromatography,17 a linear equation could be used to interpret the relation between mc/mi and Ac/Ai, which was given in eq 1. mc A = k i c + bi mi Ai (1)
1-decanol
1-octanol
T/K
103x
T/K
103x
T/K
103x
349.15 355.15 360.15 365.15 370.15 375.15 382.15 387.15 393.15
0.762 0.802 0.865 1.100 1.298 1.401 1.563 1.857 2.029
348.15 353.15 357.15 367.15 372.15 377.15 382.15 387.15 392.15
0.902 0.984 1.186 1.536 1.782 2.040 2.394 2.640 3.266
345.15 355.15 364.15 369.15 374.15 379.15 383.15
0.980 1.529 1.920 2.279 2.407 2.895 3.408
a
x is the mole fraction of D-glucose. T is the equilibrium temperature. Standard uncertainties u are u(T) = 0.30 K, ur(p) = 0.05, ur(x) = 0.016.
alcohols increased with the equilibrium temperature increasing, the solubility decreased with the increase of fatty alcohol chain length. Three models, the modified UNIQUAC model, S-UNIFAC model, and mS-UNIFAC model, were used to predict the solubility data. The determination of interaction parameters was as follows. The given initial value of interaction parameters to be determined, together with other parameters obtained from literature, allowed the calculation of the activity coefficient of Dglucose, γ. Knowing γ, the solubility of D-glucose could be calculated by means of an iterative procedure. The calculated solubility data and experimental data were compared. A nonlinear optimization method, which was implemented in Matlab Toolbox, was used to update the value of interaction parameters, minimizing the difference between the experimental and simulated data. In the modified UNIQUAC model, the equation adopted to describe the solubility of D-glucose was13
The parameters of ki and bi were determined with experiment data. The standard curves were mc/mi = 1.1454Ac/Ai + 179.23 (R2 = 0.993), mc/mi = 1.5693Ac/Ai − 75.423 (R2 = 0.997) and mc/mi = 1.0649 Ac/Ai + 124.26 (R2 = 0.995) for 1-dodecanol, 1decanol, and 1-octanol, respectively. The mass or mole fraction of D-glucose in fatty alcohol could be obtained with the analysis results substituted into eq 1. 2.3. Procedure. Solubility was measured by the equilibrium method. Excessive solute and solvent were placed in a sealed glass cell (250 mL). The temperature was controlled within ± 0.1 K of the desired temperature with a thermoelectric controlling system. Continuous stirring was carried out for 48 h with a magnetic bar. The cell was sealed by a rubber stopper to prevent evaporation of solvent. Attainment of equilibrium was verified by repetitive measurements after 48 h. At each temperature, a part of
⎡ ΔHf ΔA − ΔBT 0 ΔB 2 ⎤ Tm ⎥ Tm + ln(γ·x) = ⎢ − + R 2R ⎦ ⎣ R ⎛1 1 ⎞ ΔA − ΔBT 0 ⎛ T ⎞ l n⎜ ⎟ ×⎜ − ⎟+ Tm ⎠ R ⎝ Tm ⎠ ⎝T ΔB (T − Tm) + 2R
(2)
where x and γ are the mole fraction and activity coefficient of Dglucose, respectively; The activity coefficient γ is composed of a combinatorial term γc and residual term γR; the equations adopted to calculate γc and γR are given in the literature.16 T is the equilibrium temperature; Tm is the melting temperature of D2041
dx.doi.org/10.1021/je4011097 | J. Chem. Eng. Data 2014, 59, 2040−2044
Journal of Chemical & Engineering Data
Article
glucose; T0 is an arbitrary reference temperature, which is set to be 298.15 K; R is the gas constant; ΔHf is the enthalpy of fusion at Tm; ΔA and ΔB are two parameters that allow the calculation of the difference between the heat capacities of the pure liquid and the pure solid D-glucose. In the modified UNIQUAC model, the value of ΔHf, ΔA, ΔB, the applied molecular volume parameters and surface area parameters of D-glucose were all taken from Peres and Macedo.13 The molecular volume and surface area parameters of fatty alcohol were calculated from the size parameters of the groups involved in the molecules.19 The interaction parameters between D-glucose and different fatty alcohol were determined by the correlation of solubility data, which are listed in Table 3. The prediction results with the modified UNIQUAC model are shown in Figure 1. It was found from Figure 1 that the prediction results agreed well with the experimental results.
parameters, and modified group area parameters were taken from literature.19 In the mS-UNIFAC model, eq 3 was also applied to describe the solubility of D-glucose. The equation to calculate γc was the same as described by Larsen et al.16 The method of group division followed the method in literature.15 ΔHf, Δcp, and Tm values for D-glucose were taken from Tsavas et al.,15 group volume parameters, group area surface parameters, and modified group area parameters were taken from the literature.16 When the S-UNIFAC model and mS-UNIFAC model were used to predict the solubility data, it was found that the deviations between calculated and experimental solubility data were very large, if the group interaction parameters in literature were used.14,15 In literature, the interaction parameters were determined with the solubility data of D-glucose in methanol, ethanol, etc., chain length of which were short. Furthermore, the equilibrium temperatures in literature were much lower than that in this paper. So, it is necessary to redetermine the group interaction parameters between CHOHsug and other groups, to predict the solubility of D-glucose in fatty alcohol with the SUNIFAC model and mS-UNIFAC model. The group interaction parameters are given in Tables 4 and 5, the predicted results with S-UNIFAC model and mS-UNIFAC model and experimental data are shown in Figure 2.
Table 3. Interaction Parameters (αij, K) for Modified UNIQUAC Model j i
D-glucose
1-dodecanol
1-decanol
1-octanol
D-glucose 1-dodecanol 1-decanol 1-octanol
0 −66.100 −20.408 12.848
782.611 0
467.589
331.462
0
Table 4. Interaction Parameters (Aij, K) for the S-UNIFAC Model
0
j i CH2 OH CH−O CHOHsug a
CH2
OH
CH−O
CHOHsug
0 a a 2248.400
a 0 a −52.418
a a 0 −9347.400
30.209 −422.020 −1415.200 0
Interaction parameters from literature.14
Table 5. Interaction Parameters (Aij, K) for the mS-UNIFAC Model j
Figure 1. Experimental and calculated solubility data with the modified UNIQUAC model; −, calculated data with modified UNIQUAC model; □, experimental data in 1-dodecanol; ○, experimental data in 1-decanol; △, experimental data in 1-octanol; xi is the mole fraction of D-glucose, and T is the equilibrium temperature.
i CH2 OH CH−O CHOHsug a
In the S-UNIFAC model, the equation used to describe the solubility of D-glucose in fatty alcohol was14
⎛T ⎞ ln⎜ ⎟ R ⎝ Tm ⎠
OH
CH−O
0
a
a
a
0
a
a
a
5323.000
−171.630
0 1168.000
CHOHsug 10.285 −264.020 −1288.700 0
Interaction parameters from literature.15
The average relative deviation (ARD) was calculated with the following equation:
ΔHf ⎛ T ⎞ Δcp ⎛ Tm − T ⎞ ⎜ ⎟ ln(γ·x) = − ⎟+ ⎜1 − RT ⎝ Tm ⎠ R ⎝ T ⎠ +
CH2
ARD =
∑i |(xiexp − xical)/xiexp|
(4) NDP where xi represents the mole fraction of D-glucose in fatty alcohol; superscripts cal and exp mean calculated values and experimental data, respectively. NDP is the number of experimental data points. The ARD values for the three models are listed in Table 6. The value of interaction parameters in Tables 3 to 5 described the interaction activity of different molecules or groups. Compared with S-UNIFAC model and mS-UNIFAC model, the modified UNIQUAC model showed better prediction accuracy, and this demonstrated the applicability of this model
Δcp
(3)
The activity coefficient of D-glucose, γ, is also composed of a combinatorial term γc and residual term γR. The equation adopted to calculate γR had the same form as the original UNIFAC model. The method of group division followed the method in literature.14 Δcp is the difference between the heat capacities of the pure liquid and the pure solid D-glucose. ΔHf, Δcp, and Tm values for D-glucose were taken from Spiliotis and Tassios.14 Group volume parameters, group area surface 2042
dx.doi.org/10.1021/je4011097 | J. Chem. Eng. Data 2014, 59, 2040−2044
Journal of Chemical & Engineering Data
■
Article
ASSOCIATED CONTENT
S Supporting Information *
Solubility of D-glucose in fatty acids; graph of the variation of mc/ mi as a function of Ac/Ai. This material is available free of charge via the Internet at http://pubs.acs.org.
■
AUTHOR INFORMATION
Corresponding Author
*Tel.: 0086-571-88320053. Fax: 0086-571-87313608. E-mail:
[email protected]. Funding Figure 2. Experimental and calculated solubility data with the SUNIFAC and mS-UNIFAC model; −, calculated data with S-UNIFAC model; ..., calculated data with mS-UNIFAC model; □, experimental data in 1-dodecanol; ○, experimental data in 1-decanol; △, experimental data in 1-octanol; xi is the mole fraction of D-glucose, and T is the equilibrium temperature.
Financial support from the Key Laboratory of Biofuel Utilization Technology of Zhejiang Province (No. 20120105) is gratefully acknowledged. Notes
The authors declare no competing financial interest.
■
Table 6. Comparison of the ARD Values Calculated with Different Models
(1) Rybinski, W. V. Alkyl glycosides and polyglycosides. J. Colloid Interface Sci. 1996, 1, 587−597. (2) Geetha, D.; Tyagi, R. Alkyl poly glucosides (APGs) surfactants and their properties: A Review. Tenside Surfact. Deterg. 2012, 49, 417−427. (3) El-Sukkary, M. M. A. Synthesis and characterization of some alkyl polyglycosides surfactants. J. Surfact. Deterg. 2008, 11, 129−137. (4) Ware, A. M.; Waghmare, J. T. Alkylpolyglycoside: Carbohydrate based surfactant. J. Dispers. Sci. Technol. 2007, 28, 437−444. (5) Hill, K.; Rhode, O. Sugar-based surfactants for consumer products and technical application. Fett-Lipid. 1999, 101, 25−33. (6) Rybinski, W. V.; Hill, K. Alkyl polyglycosides-properties and application of a new class of surfactants. Angew Chem. Int. Ed. 1998, 37, 1328−1345. (7) Gorius, O.; Bertho, J.; Nuzillard, J. Determination and prediction of the average polymerization degree of alkyl polyglucosides. Anal. Chim. Acta 2001, 440, 231−237. (8) Wei, D.; Pei, Y.; Zhang, C. Measurement and correlation of solid− liquid equilibria of phenyl salicylate with C4 alcohols. Chin. J. Chem. Eng. 2009, 17, 140−144. (9) Xia, Q.; Ma, P. Measurement and correlation for solubility of dimethyl-2,6-naphthalene dicarboxylate in organic solvents. Chin. J. Chem. Eng. 2007, 15, 215−220. (10) Fan, Y.; Peng, H.; Xie, K. Measurement and correlation of the solubility of 1-hydroxyphenazine in different solvents at temperature from 278.5 to 333.5 K. J. Shanghai Jiaotong Univ. 2013, 18, 252−256. (11) Gong, X.; Lu, Y.; Luo, G. Phase equilibrium calculations in mixture containing caprolactam with a UNIFAC model. Chin. J. Chem. Eng. 2010, 18, 286−291. (12) Medo, E. A.; Peres, A. M. Thermodynamics of ternary mixture 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. (13) Peres, A. M.; Macedo, E. A. Thermodynamics properties of sugars in aqueous solutions: Correlation and prediction using a modified UNIQUAC model. Fluid Phase equilib. 1996, 123, 71−95. (14) Spiliotis, N.; Tassios, D. A UNIFAC model for phase equilibrium calculations in aqueous and nonaqueous sugar solutions. Fluid Phase Equilib. 2000, 173, 39−55. (15) Tsavas, P.; Voutsas, E.; Magoulas, K. Phase equilibrium calculations in aqueous and nonaqueous mixture of sugars and sugar derivatives with a group-contribution model. Ind. Eng. Chem. Res. 2004, 43, 8391−8399. (16) 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. (17) Skoog, D. A.; Holler, F. J.; Crouch, S. R. Principles of Instrumental Analysis; Cengage Learning: MI, 2006.
ARD value solvent 1-dodecanol 1-decanol 1-octanol
modified UNIQUAC
S-UNIFAC
mS-UNIFAC
4.3% 1.9% 4.2%
10.5% 2.7% 4.9%
7.1% 4.1% 5.3%
REFERENCES
for D-glucose solubility prediction. In Table 6, the average relative deviation with the S-UNIFAC and mS-UNIFAC models for 1decanol and 1-octanol was much lower than that for 1-dodecanol. The possible reason may be that the increase of alcohol chain length increased the complexity of the interaction activity, and it was difficult to predict the solubility in higher chain length fatty alcohol accurately with the existing parameters. On the other hand, the average relative deviations for the S-UNIFAC and mSUNIFAC model were below 10 % on most occasions. In consideration of this factor, the three models could be used to simulate the solubility of D-glucose in fatty alcohol. D-Glucose consists of five hydrophilic hydroxyls. The hydrophobicity of fatty alcohol restricted the dissolution of D-glucose. The dissolution process of D-glucose was endothermic. Therefore, the solubility of D-glucose in fatty alcohol increased with the increase of alcohol chain length, and increased with the increase of equilibrium temperature, which could be seen from Figures 1 and 2.
4. CONCLUSIONS The solubility of D-glucose in fatty alcohol (1-dodecanol, 1decanol, 1-octanol) from 343.15 K to 393.15 K were determined. The solubility of D-glucose decreased with the chain length of fatty alcohol increasing. This indicates that the mass transfer resistance effect was more significant in the glycosylation reaction of D-glucose with higher chain length fatty alcohol. The modified UNIQUAC model, S-UNIFAC model, and mSUNIFAC model were applied to predict the solid−liquid equilibrium in the D-glucose and fatty alcohol system, and the interaction parameters were determined. In the three models, the modified UINIQUAC showed better prediction accuracy. Generally, the three models all could be used to predict the solubility data. 2043
dx.doi.org/10.1021/je4011097 | J. Chem. Eng. Data 2014, 59, 2040−2044
Journal of Chemical & Engineering Data
Article
(18) Spilker, R.; Menzebach, B.; Schneider, U.; Venn, I. Analysis of alkyl polyglucosides. Tenside Surf. Deterg. 1996, 33, 21−25. (19) Magnussen, T. UNIFAC parameter table for prediction of liquid− liquid equilibria. Ind. Eng. Chem. Proc. DD 1981, 20, 331−339.
2044
dx.doi.org/10.1021/je4011097 | J. Chem. Eng. Data 2014, 59, 2040−2044
