Article pubs.acs.org/jced
Measurement and Correlation of the Solubility of 2,6Dihydroxybenzoic Acid in Alcohols and Binary Solvents Yuyan Wang,† Yanxin Chen,‡ Peipei Zhu,† Ying Bao,†,∥ Chuang Xie,†,∥ Junbo Gong,†,∥ Xiaobin Jiang,§ Baohong Hou,†,∥ and Wei Chen*,†,∥ †
National Engineering Research Center of Industry Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China ‡ Sinopec Shanghai Research Institute of Petrochemical Technology, Shanghai 201208, China § State Key Laboratory of Fine Chemicals, R&D Center of Membrane Science and Technology, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China ∥ Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin), Tianjin 300072, China S Supporting Information *
ABSTRACT: Experimental data on the solubility of 2,6dihydroxybenzoic acid (2,6-DHBA) in methanol, ethanol, 2propanol, 1-butanol, and three binary solvent systems (methanol + water, ethanol + water, and 2-propanol + water) from (278.15 to 318.15) K were measured by the gravimetric method. The experimental results indicated that the solubility of 2,6-DHBA in those solvents increased with increasing temperature. The solubilities of 2,6-DHBA in different pure solvents accorded with the following order: 1-butanol < methanol < ethanol < 2propanol. In the binary solvent systems, the solubility decreased with increasing mole ratio of water. The experimental solubility data were correlated by the modified Apelblat equation. The NIBS/Redlich−Kister model was introduced to correlate the solubility data in the binary solvent systems.
1. INTRODUCTION 2,6-Dihydroxybenzoic acid (2,6-DHBA, C7H6O4, CAS no. 30307-1), whose chemical structure is shown in Figure 1, has
appropriate solvents since they are more economical and safer compared with other organic solvents.6 Although data on the solubility of 2,6-DHBA in the corresponding pure and binary solvent systems are essential to the optimization and control of its dilute crystallization process, there have been few reports on the solubility of 2,6-DHBA. Thus, the objective of this work was to obtain the solubility of 2,6-DHBA in pure organic solvents and binary solvent systems in the temperature range from (278.15 to 318.15) K at atmospheric pressure by the gravimetric method.4,7 The pure organic solvents included methanol, ethanol, 2-propanol, and 1-butanol, while the binary ones were methanol + water, ethanol + water, and 2-propanol + water. The solubility data in pure solvents were correlated using the modified Apelblat equation, while those in binary solvents were correlated using the NIBS/Redlich−Kister model.
Figure 1. Chemical structure of 2,6-DHBA.
2. EXPERIMENTAL SECTION 2.1. Materials. 2,6-DHBA and salicylic acid were provided by Aladdin Chemical Co. Ltd. (Shanghai, China) with massfraction purities higher than 0.98 and 0.99, respectively. 2,6DHBA was purified by recrystallization in methanol. All of the solvents used in this work, including methanol, ethanol, 1-
gained considerable importance recently because of its diverse biological activity and synthetic applications.1 For example, 2,6DHBA has been applied as a useful starting material for the synthesis of herbicide.2 It has also been widely used as an intermediate for active pharmaceutical ingredients, such as bispyribac-sodium, pyrithiobac-sodium, and pyribenzoxim.3,4 2,6-DHBA can be purified by crystallization, but few studies have focused on it.5 Preliminary tests carried out in our laboratory showed that water is an effective antisolvent for dilution crystallization of 2,6-DHBA. Several lower alcohols are © 2017 American Chemical Society
Received: November 16, 2016 Accepted: August 29, 2017 Published: September 11, 2017 3009
DOI: 10.1021/acs.jced.6b00957 J. Chem. Eng. Data 2017, 62, 3009−3014
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Table 1. Provenance and Purities of the Samples Used chemical name
CAS no.
2,6-DHBA methanol ethanol 2-propanol 1-butanol salicylic acid 1-propanol
303-07-1 67-56-1 64-17-5 67-63-0 71-36-3 69-72-7 71-23-8
source Aladdin Chemical Co. Ltd. Tianjin Jiangtian Chemical Co., Tianjin Jiangtian Chemical Co., Tianjin Jiangtian Chemical Co., Tianjin Jiangtian Chemical Co., Aladdin Chemical Co. Ltd. Tianjin Jiangtian Chemical Co.,
Ltd. Ltd. Ltd. Ltd. Ltd.
purification method
mass-fraction purity
recrystallization from methanol none none none none none none
0.98 ≥0.995 ≥0.995 ≥0.995 ≥0.995 ≥0.99 ≥0.995
Table 2. Comparison of the Experimental Solubilities of Salicylic Acid in 1-Propanol at (298.2 to 338.2) K and p = 101.3 kPa with Data Reported in the Literaturea T/K
b xlit 0
c xexp 0
relative deviation/%
298.2 308.2 318.2 328.2 338.2
0.1320 0.1500 0.1630 0.1790 0.1950
0.1265 0.1576 0.1588 0.1883 0.1901
−4.2 5.1 −2.6 5.2 −2.5
a
The standard uncertainty u is u(T) = 0.03 K; the relative standard uncertainties ur are ur(p) = 0.005 and ur(x0) = 0.025. bxlit 0 is molefraction solubility of salicylic acid in 1-propanol at temperature T is the experimental mole-fraction reported in the literature.8 cxexp 0 solubility of salicylic acid in 1-propanol at temperature T determined in this work. Figure 2. DSC curve of 2,6-DHBA/furoic acid with a melting temperature of 440.2 K and an enthalpy of fusion of 25.30 kJ·mol−1.
Table 3. Comparison of the Experimental Solubilities of Salicylic Acid in the Binary Solvent Water + 1-Propanol at 298.2 K and p = 101.3 kPa with Data Reported in the Literaturea x1b
c xlit 2
d xexp 2
relative deviation/%
0.731 0.545 0.411 0.310 0.231
0.1380 0.1210 0.0975 0.0637 0.0467
0.1334 0.1162 0.0958 0.0663 0.0492
−3.3 −4.0 −1.7 4.1 5.4
2.3. Solubility Measurements. The data on the solubility of 2,6-DHBA in alcohols and binary solvents were measured by the gravimetric method, which has been described previously in other papers related to the measurement of solubility.4,7 The apparatus applied consisted of a 100 mL jacketed glass vessel and a laser monitoring system, which included a photoelectric transformer, a laser generator, and a recorder. An external thermostat (CF41, Julabo, Seelbach, Germany) with a standard uncertainty of 0.03 K was used to maintain the system temperature. To maintain constant stirring, a magnetic stirring bar was used. During the measurements, a Mettler-Toledo AB204-N electronic analytical balance was used. The gravimetric method is summarized as follows: First, a certain amount of solvent was added to the jacketed vessel and kept at the desired temperature. Next, the solute (2,6-DHBA) was added in small amounts for many times with stirring. The turbidity of solution, as a characteristic to estimate whether the solution is saturated, was monitored by the laser monitoring system. After a batch of solute was added, if the solution remained unsaturated, it would turn clear, and the intensity of the laser penetrating through the solution would vary as follows: decreasing, fluctuating, then returning to its maximum. Then the next batch of solute could be added. When the solution was saturated, detectable particles were suspended in the solution, so the laser intensity showed obvious fluctuations. At the end of experiment, the solute was added to the vessel in a very small amount with a long enough time interval that the suspended particles were as few as could be detected and the intensity of the laser kept fluctuating. Thus, the amounts of the solute and solvent can be calculated in this experiment. All of the experiments were repeated three times to verify the uncertainties. The mole-fraction solubility x1 can be obtained using eq 1:
a
The standard uncertainty u is u(T) = 0.03 K; the relative standard uncertainties ur are ur(p) = 0.005 and ur(x2) = 0.25. bx1 is the mole fraction of 1-propanol in the water + 1-propanol binary solvent at 298.2 K. cxlit 2 is the mole-fraction solubility of salicylic acid in the binary solvent at 298.2 K reported in the literature.8 dxexp 2 is experimental mole-fraction solubility of salicylic acid in the binary solvent at 298.2 K determined in this work.
propanol, 2-propanol, and 1-butanol, were supplied by Tianjin Jiangtian Chemical Co., Ltd. (Tianjin, China) and used without further purification. Their mass-fraction purities were greater than 0.995. The sources and purities of the materials are listed in Table 1. The organic solvents were stored over freshly activated molecular sieves of type 4A for about a week before experiments. Deionized water was redistilled and used throughout. 2.2. Measurements of Melting Properties. The melting temperature (Tm) and enthalpy of fusion (ΔHfus) of 2,6-DHBA were determined by differential scanning calorimetry (DSC 1/ 500, Mettler Toledo, Switzerland) under a nitrogen atmosphere (2.5 mL·s−1). Recalibrations of the temperature and heat flow of the instrument were performed with a high-purity indium standard before measurement. Approximately 3.79 mg of 2,6DHBA was added to the DSC pan, which was then heated from (298.15 to 523.15) K at a heating rate of 5 K·min−1. 3010
DOI: 10.1021/acs.jced.6b00957 J. Chem. Eng. Data 2017, 62, 3009−3014
Journal of Chemical & Engineering Data x1 =
Article
ln x1 = B0 + B1x 2 + B2 x 2 2 + B3x 2 3 + B4 x 2 4
m1/M1 m1/M1 + m2 /M 2
(1)
where B0, B1, B2, B3, and B4, are parameters of this model obtained by least-squares analysis of the experimental solubility data, x1 is the mole-fraction solubility of 2,6-DHBA in the binary solvent, and x2 is the alcohol mole fraction in the binary solvent.
where mi and Mi stand for the total masses used in the experiment and the molar masses, respectively, and the subscripts 1 and 2 represent the solute and solvent, respectively. To verify the reliability and accuracy of the experimental apparatus and method, two sets of verification measurements were carried out in which the mole-fraction solubilities of salicylic acid in a pure solvent (1-propanol) and a binary system (water + 1-propanol) were measured. The comparisons of the experimental and published8 solubility data (Tables 2 and 3) showed good consistencies, indicating the validity of the experimental techniques applied in this work. 2.4. X-ray Powder Diffraction Analysis. To identify the crystallinity of the experimental material, the X-ray powder diffraction (XRPD) spectrum of the sample was measured. Data collection was performed on a D/Max-2500 diffractometer (Rigaku, Japan) using Cu Kα radiation (0.71073 Å) over the 2θ range of 2° to 50° with a scanning rate of 0.067 deg·s−1. According to the literature, there are two polymorphs, I and II, with space groups P21/c and Pna21, respectively,9,10 and a stable monohydrate of 2,6-DHBA.1,9 According to the XRPD and DSC characterizations (Figure S1 and Figure 2, respectively), the 2,6-DHBA in this work was form I. To minimize the effect of the probable solid-phase transition on the solubility data, this method was applied. Since every batch of solute with a small amount could not be added to the solution unless the last batch completely dissolved, just a few particles were kept suspended in the solution so that the possible solvent-induced transformation among polymorphs of the solute could be neglected.
4. RESULTS AND DISCUSSION 4.1. Melting Properties of 2,6-DHBA. The DSC analysis results for 2,6-DHBA are shown in Figure 2. It was found that Table 4. Experimental and Calculated Mole-Fraction Solubilities of 2,6-DHBA in the Selected Alcohols over the Temperature Range from (278.15 to 38.15) K at p = 101.3 kPaa T/K 278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15 278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15
3. EXPERIMENTAL DATA REDUCTION In this work, the experimental solubility data of 2,6-DHBA in pure solvents were correlated using the modified Apelblat equation, and the nonrandom two liquid (NRTL) model was used to calculate the thermodynamic properties. In addition, the experimental solubility data in binary mixtures of methanol + water, ethanol + water, and 2-propanol + water were correlated with the NIBS/Redlich−Kister model. 3.1. Modified Apelblat Equation. The modified Apelblat equation11 is a frequently used empirical model for correlating the mole-fraction solubility and the absolute temperature T: ln x1 = A +
B + C ln(T /K ) T /K
278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15
(2)
where x1 is the mole-fraction solubility of 2,6-DHBA, T is the absolute temperature, and A, B, and C are the empirical constants. The values of A and B represent the variation in the solution activity coefficient, while the value of C reflects the effect of temperature on the fusion enthalpy.12 3.2. NIBS/Redlich−Kister Model. The nearly ideal binary solvent (NIBS)/Redlich−Kister model13 was proposed by Acree and co-workers and is given by eq 3:
278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15
n
ln x1 = x B ln XB + xC ln XC + x BxC ∑ si(xC − x B)i i=0
(4)
(3)
where xB and xC are the initial mole fractions of the binary solvent calculated without the presence of the solute and XB and XC are the saturated mole-fraction solubilities of the solute in the pure solvents. For the binary solvent, eq 4 is shown as follows:14
b 10·xexp 0
c 10·xcal 0
Methanol 1.9966 2.1374 2.2653 2.4710 2.6061 2.7568 2.8369 3.0040 3.1383 Ethanol 2.2095 2.3441 2.4541 2.5768 2.7253 2.8595 2.9377 3.0576 3.1762 2-Propanol 2.2486 2.3999 2.5356 2.6810 2.7985 2.9229 3.0328 3.1491 3.2310 1-Butanol 1.8871 2.0220 2.1608 2.3020 2.4488 2.5975 2.7494 2.9042 3.0617
1.9876 2.1424 2.2963 2.4470 2.5941 2.7368 2.8739 3.0050 3.1293 2.2095 2.3441 2.4541 2.5768 2.7253 2.8595 2.9377 3.0576 3.1762 2.2487 2.3999 2.5356 2.6810 2.7984 2.9227 3.0328 3.1492 3.2311 1.8871 2.0219 2.1605 2.3028 2.4485 2.5974 2.7494 2.9042 3.0618
a The standard uncertainty u is u(T) = 0.03 K; the relative standard is the uncertainties ur are ur(p) = 0.005 and ur(x0) = 0.025. bxexp 0 experimental mole-fraction solubility of 2,6-DHBA in the organic solvent at temperature T. cxcal 0 is the calculated mole-fraction solubility of 2,6-DHBA in the organic solvent at temperature T.
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for Tm is 0.3 K, and relative standard uncertainty for ΔfusH is 0.03. 4.2. Solubility Data of 2,6-DHBA in Pure Solvents. To investigate the effect of temperature on the solubility of 2,6DHBA in pure solvents, the average solubility values of 2,6DHBA in each solvent, including methanol, ethanol, 2propanol, and 1-butanol, were measured from (278.15 to and xcal 318.15) K, as presented in Table 4 (xexp 0 0 are the measured and calculated solubilities of 2,6-DHBA in the alcohol, respectively). The solubilities in the pure alcohols were found to increase with increasing temperature, and the solubilities in the four solvents at constant temperature are ranked as 1-butanol < methanol < ethanol < 2-propanol. It was found that the solubility of 2,6-DHBA increases as the carbon chain length of the alcohol increases, except for 1-butanol. This sequence is not consistent with the order of either the polarities18 or the Hildebrand solubility parameters (as calculated by Integrated Computer Aided System (ICAS) software19) of the solvents, which are shown in Table S1 in the Supporting Information. This result suggests that neither the polarity nor the cohesion energy of the solvent is the dominant factor to determine the solubility of 2,6-DHBA in the selected solvents.20 It can be considered both that the polar intermolecular interactions dominate because of the hydroxyl
Table 5. Parameters of the Modified Apelblat Thermodynamic Model Used with the Pure Solvents parameter
methanol
2-propanol
ethanol
1-butanol
A B C
73.60 −4181.20 −10.70
−33148.00 17945.00 1.00
41.80 −2598.70 6.00
8.80 −1362.50 −1.00
the onset melting temperature (Tm) and the enthalpy of fusion (ΔfusH) of 2,6-DHBA are 440.2 K and 25.3 kJ·mol−1, respectively. The melting temperature and the enthalpy of fusion, determined in this work as the mean extrapolated onset temperature, show fairly good agreement with the data in the literature (Tm = 439 K15 and Tm = 445.8 K;16 ΔfusH = 25 ± 1 kJ·mol−1 17). These subtle inconsistencies may be due to differences in several possible factors, such as experimental methods, purity of samples, and measurement conditions. The entropy of fusion of 2,6-DHBA (ΔfusS) was calculated using the following equation:
ΔfusS =
ΔfusH Tm
(5)
According to the above equation, the value of ΔfusS was determined to be 57.47 J·mol−1·K−1. The standard uncertainty
Table 6. Experimental Solubility Data of 2,6-DHBA in Binary Solvents over the Temperature Range from (278.15 to 38.15) K at p = 101.3 kPaa b 100·xexp 1
x2c
278.15 K
283.15 K
288.15 K
0.8350 0.6922 0.5675 0.4575 0.3599 0.2727 0.1942 0.1232 0.0588
14.555 8.0450 4.3330 1.9950 0.9040 0.4260 0.1990 0.1230 0.0435
17.401 9.6030 5.4500 2.6020 1.2080 0.4680 0.2320 0.1470 0.0759
20.111 11.366 6.6150 3.4020 1.5530 0.7030 0.2940 0.1720 0.1110
0.7787 0.6100 0.4771 0.3697 0.2811 0.2068 0.1435 0.0891 0.0416
12.851 6.7860 4.5680 3.1030 1.5910 0.6550 0.2940 0.1890 0.0657
14.167 7.0340 5.3680 3.3940 1.7690 0.7770 0.3850 0.2010 0.1270
16.109 7.5460 6.3280 4.2820 2.2520 1.1410 0.4880 0.2220 0.1830
0.7297 0.5454 0.4117 0.3103 0.2307 0.1667 0.1139 0.0698 0.0323
10.093 7.4300 4.2680 3.1290 1.4770 1.2570 0.4730 0.1690 0.0891
11.707 8.4080 5.1690 3.8450 2.0690 1.5330 0.6540 0.1780 0.1330
13.504 9.3180 6.2390 4.5050 2.8550 1.8320 0.8630 0.2190 0.1810
293.15 K
298.15 K
Methanol + Water 22.338 24.019 13.189 15.080 8.0290 9.7370 4.4070 5.6320 1.9930 2.6170 1.0720 1.6970 0.3670 0.4780 0.1880 0.2410 0.1390 0.1980 Ethanol + Water 18.366 20.708 8.3040 9.2920 7.4240 8.6420 5.3390 6.4550 2.8980 3.6320 1.8100 2.4620 0.6140 0.8030 0.2930 0.3770 0.2050 0.2350 2-Propanol + Water 15.362 17.194 10.414 11.723 7.4330 8.7170 5.1710 5.9590 3.6570 4.4450 2.2170 2.7190 1.0890 1.3940 0.3590 0.5560 0.2450 0.2890
303.15 K
308.15 K
313.15 K
318.15 K
25.276 17.128 11.686 7.0840 3.5190 2.5230 0.6780 0.3450 0.2180
26.322 19.437 13.777 8.7600 4.7690 3.4220 1.0270 0.4840 0.2550
27.358 22.049 15.917 10.635 6.3820 4.2780 1.5810 0.6400 0.3190
28.472 24.877 18.076 12.658 8.2850 5.0870 2.3710 0.8390 0.4180
22.979 10.493 9.9710 7.6320 4.4240 3.0660 1.1140 0.4910 0.2680
25.084 11.893 11.405 8.9330 5.2870 3.7060 1.5990 0.6720 0.3310
26.978 13.480 12.934 10.434 6.2590 4.5220 2.2880 0.9620 0.4270
28.656 15.241 14.544 12.179 7.3950 5.6580 3.1700 1.3950 0.5590
18.945 13.147 10.068 6.9980 5.2800 3.3410 1.8030 0.8060 0.3390
20.587 14.559 11.482 8.3820 6.2630 4.0650 2.3070 1.1030 0.4150
22.126 15.902 12.971 10.126 7.4760 4.8600 2.8830 1.4400 0.5350
23.592 17.291 14.567 12.122 8.9330 5.6850 3.5010 1.8110 0.7100
a
The standard uncertainty u is u(T) = 0.03 K; the relative standard uncertainties ur are ur(p) = 0.005, ur(x1) = 0.25, and ur(x2) = 0.25. bxexp 1 is the experimental mole-fraction solubility of 2,6-DHBA in the binary solvent at temperature T. cx2 is the mole fraction of alcohol in the cosolvent mixture. 3012
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and carboxyl groups and that the nonpolar interactions induced by the benzene ring and the hydrocarbon chain have a significant influence on the dissolution thermodynamics of 2,6DHBA in these solvents. The actual factor influencing the dissolution capacity of 2,6-DHBA in the selected solvents requires further study. To extend the application range of the solubility data and describe the solid−liquid equilibrium quantitatively, the experimental solubility data were correlated using the modified Apelblat equation. The calculated solubility data are also given in Table 4. The model parameters were obtained by fitting the experimental solubility data and minimizing the objective function f = (xcal − xexp)/xexp. The obtained model parameters are shown in Table 5. The average relative deviation (ARD) was used to identify differences between the measured and calculated data according to eq 6: ARD =
1 Np
Np
∑ i=1
xical − xiexp × 100% xiexp
(6)
where Np is the number of data points for each solvent and the superscripts “exp” and “cal” stand for the experimental and calculated solubilities, respectively. The ARDs of the modified Apelblat models for the different pure alcohols, which are shown in Table S2 in the Supporting Information, are less than 2.8%. This means that the modified Apelblat equation can give satisfactory correlation results for solubility data of 2,6-DHBA in the four pure solvents tested in this work. This model can be used to predict the solubility data and mixing properties of 2,6DHBA. 4.3. Solubility Data of 2,6-DHBA in Solvent Mixtures. To evaluate the feasibility of the antisolvent crystallization method, the solubilities of 2,6-DHBA in binary solvent mixtures were experimentally determined, including methanol + water, ethanol + water, and 2-propanol + water. The solubility data are shown in Table 6 and Figure 3. The solubilities of 2,6-DHBA in the selected solvent mixtures increase with increasing mole fraction of alcohol and temperature. The NIBS/Redlich−Kister model was used to correlate the solubility data of 2,6-DHBA in the binary solvent systems. Values of the correlated B parameters and R2 are given in Table S4 in the Supporting Information. According to the results, the NIBS/Redlich− Kister model gave satisfactory correlations of the solubility data of 2,6-DHBA in binary solvent systems. Furthermore, the values B0, B1, B2, B3, and B4 were related to temperature T according to eq 7 to obtain a global expression for the solubility in the binary solvents:21 Bi = ei + fi T
(7)
where Bi denotes B0, B1, B2, B3, and B4 in eq 4, T is the absolute temperature, and ei and f i are empirical parameters. The obtained global expression for the solubility data of 2,6-DHBA in the binary solvent system is given as follows:
Figure 3. Experiment solubilities of 2,6-DHBA in (a) methanol + water, (b) ethanol + water, and (c) 2-propanol + water at different temperatures and compositions. (a) ■, x2 = 0.8350; red ●, x2 = 0.6922; blue ▲, x2 = 0.5675; dark cyan ▼, x2 = 0.4575; magenta ◀, x2 = 0.3599; dark yellow ▶, x2 = 0.2727; navy ★, x2 = 0.1942; wine □, x2 = 0.1232; pink △, x2 = 0.0588. (b) ■, x2 = 0.7787; red ●, x2 = 0.6100; blue ▲, x2 = 0.4771; dark cyan ▼, x2 = 0.3697; magenta ◀, x2 = 0.2811; dark yellow ▶, x2 = 0.2068; navy ★, x2 = 0.1435; wine □, x2 = 0.0891; pink △, x2 = 0.0416. (c) ■, x2 = 0.7297; red ●, x2 = 0.5454; blue ▲, x2 = 0.4117; dark cyan ▼, x2 = 0.3103; magenta ◀, x2 = 0.2307; dark yellow ▶, x2 = 0.1667; navy ★, x2 = 0.1139: wine □, x2 = 0.0698; pink △, x2 = 0.0323.
ln x1 = e0 + e1x 2 + e 2x 2 2 + e3x 2 3 + e4x 2 4 + (f0 + f1 x 2 + f2 x 2 2 + f3 x 2 3 + f4 x 2 4)T
(8)
According to eq 8, the solubility of 2,6-DHBA can be calculated for any other binary solution composition from (278.15 to 318.15) K. The values of the parameters of eq 8 and R2 are given in Table S3 in the Supporting Information. 3013
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Journal of Chemical & Engineering Data
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(5) Buchowski, H.; Ksiazczak, A.; Pietrzyk, S. Solvent activity along a saturation line and solubility of hydrogen-bonding solids. J. Phys. Chem. 1980, 84, 975−979. (6) Cui, P. L.; Yin, Q. X.; Gong, J. B.; Wang, Y. L.; Hao, H. X.; Xie, C.; Bao, Y.; Zhang, M. J.; Hou, B. H.; Wang, J. K. Thermodynamic analysis and correlation of solubility of candesartan cilexetil in aqueous solvent mixtures. Fluid Phase Equilib. 2013, 337, 354−362. (7) Fang, J.; Zhang, M. J.; Zhu, P. P.; Ouyang, J. B.; Gong, J. B.; Chen, W.; Xu, F. Solubility and solution thermodynamics of sorbic acid in eight pure organic solvents. J. Chem. Thermodyn. 2015, 85, 202−209. (8) Fakhree, M. A. A.; Ahmadian, S.; Panahi-Azar, V.; Acree, W. E.; Jouyban, A. Solubility of 2-Hydroxybenzoic Acid in Water, 1-Propanol, 2-Propanol, and 2-Propanone at (298.2 to 338.2) K and Their Aqueous Binary Mixtures at 298.2. J. Chem. Eng. Data 2012, 57, 3303− 3307. (9) MacGillivray, L. R.; Zaworotko, M. J. Crystal and molecular structure of 2,6-dihydroxybenzoic acid. J. Chem. Crystallogr. 1994, 24, 703−705. (10) Gdaniec, M.; Gilski, M.; Denisov, G. S. γ-Resorcylic acid, its monohydrate and its pyridinium complex. Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 1994, 50, 1622−1626. (11) Li, J. Q.; Wang, Z.; Bao, Y.; Wang, J. K. Solid−Liquid Phase Equilibrium and Mixing Properties of Cloxacillin Benzathine in Pure and Mixed Solvents. Ind. Eng. Chem. Res. 2013, 52, 3019−3026. (12) Wang, K.; Hu, Y. H.; Yang, W. G.; Guo, S.; Shi, Y. Measurement and correlation of the solubility of 2,3,4,5-tetrabromothiophene in different solvents. J. Chem. Thermodyn. 2012, 55, 50−55. (13) Hu, Y.; Kai, Y.; Cao, Z.; Li, J.; Yang, W. Measurement and correlation solubility and mixing properties of dimethyl succinylsuccinate in pure and mixture organic solvents from (278.15 to 333.15) K. Fluid Phase Equilib. 2013, 354, 259−264. (14) Ali, A.; Ali, M.; Malik, N. A.; Uzair, S.; Khan, A. B. Solvatochromic Absorbance Probe Behavior within Mixtures of the Ionic Liquid 1-Butyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide + Molecular Organic Solvents. J. Chem. Eng. Data 2014, 59, 1755−1765. (15) Sarma, B.; Saikia, B. Hydrogen bond synthon competition in the stabilization of theophylline cocrystals. CrystEngComm 2014, 16, 4753−4765. (16) Liao, X. M.; Gautam, M.; Grill, A.; Zhu, H. J. Effect of position isomerism on the formation and physicochemical properties of pharmaceutical co-crystals. J. Pharm. Sci. 2010, 99, 246−254. (17) Vecchio, S.; Brunetti, B. Thermochemical study of 2,4-, 2,6- and 3,4-dihydroxybenzoic acids in the liquid phase using a TG apparatus. Thermochim. Acta 2011, 515, 84−90. (18) Smallwood, I. M. Handbook of Organic Solvent Properties; Butterworth-Heinemann: New York, 1996. (19) Cunico, L. P.; Ceriani, R.; Sarup, B.; O’Connell, J. P.; Gani, R. Data, Analysis and Modeling of Physical Properties for Process Design of Systems Involving Lipids. Fluid Phase Equilib. 2014, 362, 318−327. (20) Carlson, R.; Lundstedt, T.; Albano, C. Screening of Suitable Solvents in Organic Synthesis. Strategies for Solvent Selection. Acta Chem. Scand. 1985, 39b, 79−91. (21) Noubigh, A.; Jeribi, C.; Mgaidi, A.; Abderrabba, M. Solubility of Gallic Acid in Liquid Mixtures of (Ethanol + Water) from (293.15 to 318.15) K. J. Chem. Thermodyn. 2012, 55, 75−78.
5. CONCLUSIONS Data on the solubility of 2,6-DHBA in methanol, ethanol, 2propanol, and 1-butanol were measured from (278.15 to 313.15) K. The mole-fraction solubility values of 2,6-DHBA in these pure solvents at constant temperature ranked as 1-butanol < methanol < ethanol < 2-propanol. The modified Apelblat equation was used to correlate the solubility data. The solubility data of 2,6-DHBA in binary solvent mixtures, including methanol + water, ethanol + water, and 2-propanol + water, were also investigated from (278.15 to 313.15) K. The solubility increased with rising temperature and increasing concentration of alcohol in the binary solvent within the studied temperature range. The NIBS/Redlich−Kister model was introduced to correlate the solubility data in the binary solvent systems and provided satisfactory fitting results. These results will be useful to optimize the dilution crystallization processes of 2,6-DHBA.
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jced.6b00957. Physicochemical properties of 2,6-DHBA and the selected solvents, results for the solubility of 2,6-DHBA in different pure and binary solvents, and parameters of the NIBS/Redlich−Kister equation (PDF)
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AUTHOR INFORMATION
Corresponding Author
*Tel.: +86-22-27405754. Fax: +86-22-27374971. E-mail:
[email protected]. ORCID
Yanxin Chen: 0000-0002-8592-5293 Junbo Gong: 0000-0002-3376-3296 Xiaobin Jiang: 0000-0003-0262-4354 Wei Chen: 0000-0002-5804-3973 Funding
This work was financially supported by the Major National Scientific Instrument Development Project of China (21527812), the National Natural Science Foundation of China (21376164 and 21376165), and the Tianjin Municipal Natural Science Foundation, China (13JCZDJC28400). Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The authors are grateful to Prof. Rafiqul Gani for providing the ICAS software. REFERENCES
(1) Davey, R. J.; Blagden, N.; Righini, S.; Alison, H.; Quayle, M. J.; Fuller, S. Crystal polymorphism as a probe for molecular self-assembly during nucleation from solutions: the case of 2, 6-dihydroxybenzoic acid. Cryst. Growth Des. 2001, 1, 59−65. (2) Hu, S. H.; Sun, X. F.; Pan, H. T. Study on the Synthesis of 2,6Dihydroxybenzoic Acid. Chem. World 2008, 2, 99−102. (3) Sheikhzadeh, M.; Rohani, S.; Taffish, M.; Murad, S. Solubility analysis of buspirone hydrochloride polymorphs: Measurements and prediction. Int. J. Pharm. 2007, 338, 55−63. (4) Zhang, J.; Yang, X.; Han, Y.; Li, W.; Wang, J. Measurement and correlation for solubility of levofloxacin in six solvents at temperatures from 288.15 to 328.15 K. Fluid Phase Equilib. 2012, 335, 1−7. 3014
DOI: 10.1021/acs.jced.6b00957 J. Chem. Eng. Data 2017, 62, 3009−3014
