Article pubs.acs.org/jced
Liquid−Liquid Equilibria for the Ternary System Water + Benzyl Alcohol + Benzaldehyde at (303.2 to 343.2) K Hui Wang,† Qinbo Wang,*,† Chuxiong Chen,‡ and Zhenhua Xiong‡ †
Department of Chemical Engineering, Hunan University, Changsha, 410082 Hunan, P. R. China Zhejiang Shuyang Chemical Co. Ltd., Quzhou, 324002 Zhejiang, P. R. China
‡
ABSTRACT: Liquid−liquid equilibrium (LLE) data for the ternary system water + benzyl alcohol + benzaldehyde were measured at (303.2 to 343.2) K under atmospheric pressure. The reliability of the experimental LLE data were checked by the Othmer−Tobias and the Hand correlations. The experimental data were correlated by both the (nonrandom two liquid) NRTL and the universal quasichemical activity coefficient (UNIQUAC) models. The relative-mean-standard deviations obtained are 0.16 % by the NRTL model and 0.14 % by the UNIQUAC model. The relevant model interaction parameters were regressed with the experimental data. The distribution coefficients and separation factors were used to discuss the ability of the solvent water to extract benzyl alcohol from binary benzyl alcohol + benzaldehyde solvent mixtures. The results show that the separation factor of benzyl alcohol increased with an increase of the mass of water and decreased with an increase of temperature, which indicates that the extraction separation of benzyl alcohol from binary benzyl alcohol + benzaldehyde mixtures by the extract agent water may be feasible. The obtained results might be used in the separation process for the ternary system water + benzyl alcohol + benzaldehyde.
1. INTRODUCTION Benzyl alcohol and benzaldehyde both are important raw materials in the production of pharmaceuticals and daily chemicals. Traditionally, both benzyl alcohol and benzaldehyde are produced by the hydrolysis process of benzyl chloride, which would simultaneously produce a large amount of acidic waste water, and cause serious environmental problems. In recent years, some researchers have found a green way to produce benzaldehyde,1−3 and these existing studies provide a new idea to produce benzyl alcohol. In this way, methylbenzene is oxidized by hydrogen peroxide, which is an excellent oxidant with its higher activity than O2. Thus, this method is cleaner, safer, and more cost-effective compared with the traditional method. In this oxidation system, the product would be a mixture of benzyl alcohol and benzaldehyde, and the reaction mixture would split into two liquid phases because of the existence of water. Thus, the liquid−liquid equilibria (LLE) data of the ternary system water + benzyl alcohol + benzaldehyde is crucial for the studies of the oxidation and sequentially separation process. The current method to separate benzaldehyde and benzyl alcohol is distillation, and the operation should be carried out under high temperature. This may cause loss of raw materials because benzaldehyde and benzyl alcohol are heat sensitive and unstable. Nevertheless, extraction might solve this problem. An initial literature survey shows that the intersolubility of benzaldehyde and water is very low, while benzyl alcohol and water has a certain amount of intersolubility. Thus, water might be chosen as an extraction agent to separate the mixture of © 2014 American Chemical Society
benzyl alcohol and benzaldehyde. With regards to this extraction, the LLE data of the ternary system water + benzyl alcohol + benzaldehyde at different temperatures and different compositions is indispensable. Until now, LLE data for binary mixtures of water + benzaldehyde4−6 and LLE data for binary mixtures of water + benzyl alcohol7−12 could be found, but no publications or reports on the ternary system of water + benzyl alcohol + benzaldehyde are available. In this work, the LLE data for the ternary system water + benzyl alcohol + benzaldehyde were measured at (303.2 to 343.2) K under atmospheric pressure. The reliability of the experimental LLE data was confirmed according to the Othmer-Tobias and the Hand correlations. The experimental data were correlated by the nonrandom two-liquid (NRTL) activity coefficient model13 and the universal quasichemical activity coefficient (UNIQUAC) activity coefficient model.14 The ability of the solvent water to extract benzyl alcohol from binary benzyl alcohol + benzaldehyde was discussed by the distribution coefficients and separation factors. The relevant interaction parameters are expected to be regressed with the experimental data. The obtained results might be used in the separation process for the ternary system water + benzyl alcohol + benzaldehyde which is an ongoing part of our work. Received: May 19, 2014 Accepted: August 4, 2014 Published: August 12, 2014 2805
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2. EXPERIMENTAL SECTION 2.1. Materials. Benzaldehyde, benzyl alcohol, and 1,4dimethylbenzene were obtained from Xilong Chemical Co., and had a declared purity of 0.990 in mass fraction. The mass fraction purities of these chemicals were checked by gas chromatography (GC). Purified water manufactured by Hangzhou Wahaha Group Co. was obtained from the supermarket (596 mL each bottle; conductivity, 0.2 S/m). All the chemicals used in the experiments were used without further purification. The description of the chemical agents used in this work is given in Table 1.
Briefly, the equilibrium experiments were carried out in 100 mL glass bottles. For each run, the prepared mixtures of known compositions were added to glass bottles. The bottles with the mixtures were put in a thermostatic water bath and heated to the desired temperature within ± 0.1 K. After reaching the desired temperature, the mixtures were stirred for 3 h, and then the mixtures were left undisturbed for the following several hours. To verify the attainment of liquid−liquid equilibrium, the two liquid phases were sampled once an hour, and the phase composition was determined. It was found that 3 h after the stirring stopped was enough time for the prepared mixture to reach liquid−liquid equilibrium, because repetitive measurements during the following several hours indicated the results were reproducible with ± 3 %. 2.3. Analysis. In each measurement, about 1.0 g of the solution was sampled for the aqueous phase, and about 0.2 g of the solution was sampled for the organic phase. All the solutions were measured accurately by an electronic analytical balance (type AL204, Mettler Toledo instrument Co. Ltd., uncertainty of 0.0001 g). The concentration of benzyl alcohol and benzaldehyde were analyzed by the gas chromatograph (KeXiao GC-1690) equipped with a flame ionization detector (FID) and a capillary column (30 m × 0.32 mm × 0.50 μm;
Table 1. Suppliers and Mass Fractions of the Materials
a
component
suppliers
mass fraction
analysis method
benzaldehyde benzyl alcohol 1,4-dimethylbenzene
Xilong Chemical Co. Xilong Chemical Co. Xilong Chemical Co.
> 0.990 > 0.990 > 0.996
GCa GCa GCa
Gas chromatograph.
2.2. Apparatus and Procedures. The experimental apparatus and sampling methods used in this work were described in detail by Wang15 et al. and our recent work.12,16
Table 2. Experimental Liquid−Liquid Equilibrium Data for System Water (1) + Benzyl Alcohol (2) + Benzaldehyde (3) for Mass Fraction w at (303.2 to 343.2) K and pressure p = 101.3 kPaa aqueous phase w1
w2
0.9925 0.9877 0.9848 0.9801 0.9760 0.9739 0.9710 0.9682 0.9623 0.9603 0.9552
0.0000 0.0052 0.0082 0.0132 0.0179 0.0206 0.0244 0.0281 0.0347 0.0382 0.0448
0.9921 0.9867 0.9830 0.9759 0.9741 0.9738 0.9681 0.9650 0.9614 0.9581 0.9529
0.0000 0.0051 0.0092 0.0166 0.0193 0.0206 0.0270 0.0308 0.0353 0.0400 0.0471
0.9919 0.9835 0.9817 0.9736 0.9721 0.9708 0.9684
0.0000 0.0070 0.0095 0.0181 0.0205 0.0226 0.0259
aqueous phase
organic phase w3
w1
T = 303.2 K 0.0075 0.0139 0.0071 0.0207 0.0070 0.0256 0.0067 0.0362 0.0061 0.0428 0.0055 0.0504 0.0046 0.0579 0.0037 0.0691 0.0030 0.0758 0.0015 0.0887 0.0000 0.1027 T = 313.2 K 0.0079 0.0185 0.0082 0.0254 0.0078 0.0320 0.0075 0.0412 0.0066 0.0493 0.0056 0.0548 0.0049 0.0676 0.0042 0.0759 0.0033 0.0843 0.0019 0.1031 0.0000 0.1056 T = 323.2 K 0.0081 0.0211 0.0095 0.0333 0.0088 0.0400 0.0083 0.0484 0.0074 0.0572 0.0066 0.0660 0.0057 0.0772
w2
w1
w3
0.0000 0.0895 0.1776 0.2738 0.3552 0.4539 0.5426 0.6266 0.7014 0.7910 0.8973
0.9861 0.8898 0.7968 0.6900 0.6020 0.4957 0.3995 0.3043 0.2228 0.1203 0.0000
0.0000 0.0907 0.1860 0.2883 0.3836 0.4693 0.5641 0.6135 0.6906 0.7787 0.8944
0.9815 0.8839 0.7820 0.6705 0.5671 0.4759 0.3683 0.3106 0.2251 0.1182 0.0000
0.0000 0.0892 0.1791 0.2663 0.3908 0.4903 0.5582
0.9789 0.8775 0.7809 0.6853 0.5520 0.4437 0.3646
w2
0.9641 0.9611 0.9559 0.9521
0.0313 0.0355 0.0419 0.0479
0.9909 0.9829 0.9795 0.9723 0.9703 0.9698 0.9670 0.9621 0.9566 0.9510 0.9515
0.0000 0.0073 0.0109 0.0190 0.0219 0.0230 0.0272 0.0330 0.0395 0.0467 0.0485
0.9896 0.9812 0.9765 0.9710 0.9688 0.9649 0.9620 0.9551 0.9536 0.9469 0.9499
0.0000 0.0074 0.0134 0.0199 0.0230 0.0276 0.0311 0.0392 0.0420 0.0506 0.0501
organic phase w3
w1
T = 323.2 K 0.0046 0.0855 0.0034 0.1052 0.0022 0.1169 0.0000 0.1128 T = 333.2 K 0.0091 0.0249 0.0098 0.0364 0.0096 0.0433 0.0087 0.0495 0.0078 0.0585 0.0072 0.0775 0.0058 0.0822 0.0049 0.0905 0.0039 0.1070 0.0023 0.1328 0.0000 0.1250 T = 343.2 K 0.0104 0.0283 0.0114 0.0414 0.0101 0.0462 0.0091 0.0516 0.0082 0.0603 0.0075 0.0784 0.0069 0.0853 0.0057 0.0947 0.0044 0.1108 0.0025 0.1350 0.0000 0.1411
w2
w3
0.6124 0.7041 0.7788 0.8872
0.3021 0.1907 0.1043 0.0000
0.0000 0.0946 0.1807 0.2739 0.4058 0.5008 0.5644 0.6297 0.7113 0.7793 0.8750
0.9751 0.8690 0.7760 0.6766 0.5357 0.4217 0.3534 0.2798 0.1817 0.0879 0.0000
0.0000 0.1016 0.2077 0.2847 0.4184 0.5114 0.5686 0.6333 0.7160 0.7828 0.8589
0.9717 0.8570 0.7461 0.6637 0.5213 0.4102 0.3461 0.2720 0.1732 0.0822 0.0000
a
Standard uncertainties u are u(T) = 0.1 K, ur(p) = 0.05, u(x1) = 0.0008, u(x2) = 0.0010, u(x3) = 0.0003.
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Figure 1. LLE of the water (1) + benzyl alcohol (2) + benzaldehyde (3) system at different temperatures: ●---●, experimental data tie line; □- - -□, correlated data tie line using NRTL model. xi is the mole fraction of component i in water (1) + benzyl alcohol (2) + benzaldehyde (3) solvent mixtures.
standard uncertainty of water in mass fraction was determined to be 0.0008.
stationary phase, AT. SE-54). The internal standard method was used, and 1,4-dimethylbenzene was chosen as the internal standard substance. The concentration of water was determined by using compact volumetric Karl Fischer titrator (MettlerToledo V20). The analytic procedure is described in detail elsewhere.15 To verify the reliability and reproducibility of the GC analysis method, five benzaldehyde and benzyl alcohol solutions of known concentration were analyzed. For each solution, the composition was measured at least three times. The standard uncertainty of benzyl alcohol in mass fraction was determined to be 0.0010, and that for benzaldehyde was determined to be 0.0003. To verify the reliability and reproducibility of the water concentration determination method, five benzyl alcohol and water solutions of known concentration were also analyzed. Similarly, each solution was measured at least three times. The
3. RESULTS AND DISCUSSION 3.1. Experimental Results. LLE data of the ternary system water (1) + benzyl alcohol (2) + benzaldehyde (3) at (303.2 to 343.2) K are shown in Table 2, and the experimental data of the ternary system at different temperatures are plotted in Figure 1 and Figure 2. The Othmer−Tobias equation17 and the Hand equation18 were used to check the reliability of experimental data. The equations used are shown as eq 1 and eq 2: ⎛ 1 − W33 ⎞ ⎛ 1 − W11 ⎞ ln⎜ ⎟ ⎟ = A + B ln⎜ ⎝ W11 ⎠ ⎝ W33 ⎠ 2807
(1)
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Figure 2. LLE of ternary water (1) + benzyl alcohol (2) + benzaldehyde (3) system at different temperatures: ●---●, experimental data tie line; □- -□, correlated data tie line using UNIQUAC model. xi is the mole fraction of component i in water (1) + benzyl alcohol (2) + benzaldehyde (3) solvent mixtures.
⎛W ⎞ ⎛W ⎞ ln⎜ 31 ⎟ = M + N ln⎜ 33 ⎟ ⎝ W11 ⎠ ⎝ W13 ⎠
Table 3. Constants of the Othmer−Tobias and Hand Equations for the Water (1) + Benzyl Alcohol (2) + Benzaldehyde (3) System at (303.2 to 343.2) K
(2)
where A, B, M, and N are the constants of the Othmer−Tobias equation and the Hand equation, respectively. W11 is the mass fraction of water in the aqueous phase, and W33 is the mass fraction of benzyldehyde in the organic phase. W31 is the mass fraction of water in the organic phase, and W13 is the mass fraction of benzyldehyde in the aqueous phase. By fitting the experimental data with eqs 1 and 2, the results are listed in Table 3, and the Othmer-Tobias and Hand plots are also shown in Figure 3 and Figure 4, respectively. As can be seen from Table 3, the linear correlation coefficients, R2, were all close to 1, which indicated that the experimental LLE data were reliable. 3.2. Verification of Measured Binary LLE Data. In this work, LLE data for the ternary system water + benzyl alcohol +
Othmer−Tobias
Hand
T/K
A
B
R2 a
M
N
R2a
303.2 313.2 323.2 333.2 343.2
−3.653 −3.607 −3.558 −3.507 −3.421
0.297 0.288 0.260 0.261 0.267
0.984 0.976 0.975 0.980 0.981
10.19 9.642 5.733 4.012 3.119
−2.912 −2.851 −1.989 −1.612 −1.425
0.975 0.966 0.965 0.962 0.970
a 2
R is the linear correlation coefficient. Standard uncertainty u is u(T) = 0.1 K.
benzaldehyde have been measured at (303.2 K to 343.2 K) under atmospheric pressure. This includes the binary LLE data of water + benzyl alcohol and water + benzaldehyde. 2808
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Figure 5. Comparisons between experimental solubility of benzaldehyde in the aqueous phase with that reported in literature: ●, experimental data; □, literature data from Stephenson;4 ○, literature data from Hertel.5
Figure 3. Othmer−Tobias plots of ternary water (1) + benzyl alcohol (2) + benzaldehyde (3) system at different temperatures: ■, 303.2 K; ▲, 313.2 K; □, 323.2 K; ○, 333.2 K; ◇, 343.2 K. W11 is the mass fraction of water in aqueous phase and W33 is the mass fraction of benzaldehyde in the organic phase.
Figure 6. Comparisons between experimental solubility of benzaldehyde in the organic phase with that reported in literature: ●, experimental data; □, literature data from Stephenson.4
Figure 4. Hand plots of ternary water (1) + benzyl alcohol (2) + benzaldehyde (3) system at different temperatures: ■, 303.2 K; ▲, 313.2 K; □, 323.2 K; ○, 333.2 K; ◇, 343.2 K. W11 and W31 are the mass fractions of water in the aqueous phase and in the organic phase, respectively. W31 and W33 are the mass fractions of benzaldehyde in the aqueous phase and in the organic phase, respectively.
To guarantee the accuracy of the data, the experimental data were also compared with the literature data of the binary mixtures which were mentioned before. The results are shown in Figure 5, Figure 6, and Figure 7. It can be found that the obtained experimental data have no important deviations with the literature data. It verifies that the measured binary data are reliable and the experimental method is accurate. 3.3. Correlation of Experimental Data. Usually the LLE data might be correlated by the UNIFAC, NRTL, or UNIQUAC activity coefficient model, and the UNIFAC model might be used to predict the LLE when experimental data are lacking. However, as verified in our previous work,12 the predicted LLE data of water + benzyl alcohol differed greatly with the experimental data, which indicated that the present UNIFAC model parameters could not be used in LLE systems including water + benzyl alcohol. In this work, the obtained experimental data were correlated by both the NRTL and the UNIQUAC models. The activities of each component i in the two coexistent liquid phases of a system at equilibrium
Figure 7. Comparisons between experimental solubility of benzyl alcohol in the aqueous phase with that reported in literature: ●, experimental data; □, literature data from Stephenson;8 ○, literature data from Solimo;10 △, literature data from Banerjee.7
might be regarded as equal, and the mole fractions xIi and xIIi of the LLE phases can be determined using eqs 3 to 6: xi = 2809
wi /Mi 3
∑i = 1 wi /Mi
(3)
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Table 4. r and q Values of the Used Pure Compounds for UNIQUAC
γi IxiI = γi IIxiII
(4)
∑ xiI = 1
(5)
component
r
q
(6)
water benzyl alcohol benzaldehyde
0.9200 4.0217 4.0197
1.4000 3.3220 3.0700
∑ xiII = 1 γIi
γIIi
where, and are the activity coefficients of component i in aqueous phase and organic phase. The key to solving the equations is to calculate the activity coefficients. The experimental data can be used to determine the interaction parameters between water, benzyl alcohol, and benzaldehyde. From the NRTL equation and the UNIQUAC equation, the interaction parameters can be used to determine the activity coefficients. The NRTL activity coefficient equations used in this work are 3
ln γi =
∑ j = 1 τjiGjixj 3
∑k = 1 Gkixk
3
+
∑ j=1
deviation (rmsd) between the experimental and the correlated mole fractions defined as 1 rmsd = N
xexp ijkt ,
3
∑k = 1 Gkjxk
(7)
bij
τij = aij +
(8)
T
Gij = exp( −αijτij)
(9)
αij = αji , τij ≠ τji , τii = 0
(10)
where T is the absolute temperature, K and aij and bij are the NRTL binary interaction parameters. The activity coefficient equations for the UNIQUAC model used in this work are ln γi = ln
ψi xi
+
ψ θ z qi ln i + li − i xi 2 ψi 3
3
∑ xjlj j=1
3
θτ j kj 3 j = 1 ∑k = 1 θτ j kj
− qi ln(∑ θτ j ji) + qi − qi ∑ j=1
lj = ψi = θi =
⎛Z⎞ ⎜ ⎟(r − q ) − (r − 1) j j ⎝2⎠ j
(11)
(12)
xiri 3
∑i = 1 xiri 3
⎛ bij ⎞ τij = exp⎜aij + ⎟ T⎠ ⎝
S=
k2 k1
(17)
k1 =
w31 w33
(18)
k2 =
w21 w23
(19)
(13)
xiqi ∑i = 1 xiqi
(16)
xcal ijkt
where N is the total number of tie lines, and are the experimental and calculated mole fractions, and subscripts i, j, k, and t denote the component, phase, tie-line, and temperature, respectively. The regressed NRTL and UNIQUAC binary interaction parameters aij and bij, along with the rmsd’s are shown in Table 5. By using the regressed model parameters, the LLE data under the experimental conditions could be simulated, and the correlated results were also given in Figures 1 and Figure 2 for comparison. As can be seen from the two figures, the experimental data agree well with the calculated data. Further, the rmsd values show that the predicted results by the UNIQUAC method are in slightly better agreement with the calculated data than those from the NRTL method. 3.4. Discussion. The experimental results given in Table 2 indicate that the solubility of benzyl alcohol in the aqueous phase is greater than that of benzaldehyde in the aqueous phase. The results given in Figure 1 and Figure 2 show that the mutual solubility of water and benzaldehyde increases slightly with the increase of benzyl alcohol’s mass fraction at settled temperatures. Within the temperature range of the measurements, the experimental data show that the mutual solubility of the mixtures slightly changed. The ability of the solvent water to extract benzyl alcohol from binary benzyl alcohol + benzaldehyde mixtures might be demonstrated by the separation factor S and distribution coefficients k1 and k2. These parameters are defined as eqs 17 to 19:
xjGij
3 ⎛ ∑k = 1 xkτkjGkj ⎞ ⎟ × ⎜⎜τij − 3 ∑k = 1 Gkjxk ⎟⎠ ⎝
⎛ x exp − x cal ⎞2 ijkt ijkt ⎜ ∑ ∑ ∑ ∑ ⎜ exp 100⎟⎟ xijkt ⎠ t k j i ⎝
(14)
where k 1 and k 2 are the distribution coefficients of benzaldehyde and benzyl alcohol between organic and aqueous phases, respectively; w31 and w33 are the mass fractions of benzaldehyde in aqueous and organic phases, respectively; w21 and w23 are the mass fractions of benzyl alcohol in aqueous and organic phases, respectively. The separation factors and distribution coefficients at different temperatures are calculated from the experimental results and summarized in Table 6. The plot for the separation factor of benzyl alcohol is shown in Figure 8. It can be seen that the separation factor of benzyl alcohol increases with an
(15)
Here ψi and θi represent the volume fraction and the area fraction, respectively. aij and bij are UNIQUAC model parameters. The pure component structural parameters (r and q) are listed in Table 4. Using NRTL model and UNIQUAC model, the experimental data were correlated, and the model parameters were optimized. The optimum algorithm applied in the parameter estimation program was the Nelder−Mead Simplex approach.19 In this work, the corresponding relative-mean-standard 2810
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Table 5. Optimized Temperature-Independent Binary Interaction Parameters for the NRTL and UNIQUAC Models for the Water (1) + Benzyl Alcohol (2) + Benzaldehyde (3) System at (303.2 to 343.2) K NRTL
UNIQUAC
i−j
αij
aij
bij
aji
bji
rmsd
1−2 1−3 2−3 1−2 1−3 2−3
0.2 0.2 0.2
0.43 0.41 −4.89 −2.93 −0.89 9.47
2931.50 1709.80 1009.50 893.12 113.19 −772.13
0.32 2.54 −6.08 2.07 1.49 −6.09
2863.30 2982.50 1845.50 −715.68 −768.40 818.51
0.16 %
0.14 %
Table 6. Distribution Coefficients of Benzyl Alcohol, Benzaldehyde k1, k2 and Separation Factors S of Benzyl Alcohol at Different Temperaturesa T/K
k1
k2
S
303.2
0.008 0.009 0.010 0.010 0.011 0.012 0.012 0.013 0.012 0.009 0.010 0.011 0.012 0.012 0.013 0.014 0.015 0.016 0.011 0.011 0.012 0.013 0.015 0.016 0.015 0.018 0.020 0.011 0.012 0.013 0.015 0.017 0.016 0.018 0.021 0.026 0.013 0.014 0.014 0.016 0.018 0.020 0.021 0.025
0.058 0.046 0.048 0.050 0.045 0.045 0.045 0.049 0.048 0.056 0.049 0.058 0.050 0.044 0.048 0.050 0.051 0.051 0.078 0.053 0.068 0.052 0.046 0.046 0.051 0.05 0.054 0.077 0.060 0.069 0.054 0.046 0.048 0.052 0.056 0.060 0.073 0.065 0.070 0.055 0.054 0.055 0.062 0.059
7.28 5.25 4.96 4.59 4.09 3.91 3.69 3.72 3.87 7.03 5.56 5.12 4.28 3.68 3.60 3.50 3.49 3.30 6.82 5.71 5.01 3.91 3.10 2.97 2.90 2.83 2.69 6.84 5.58 4.40 3.71 3.39 2.94 2.90 2.59 2.29 5.48 4.77 4.40 3.49 2.95 2.74 2.55 2.31
313.2
323.2
333.2
343.2
a
Figure 8. Separation factor of benzyl alcohol versus the mass fraction of water at different temperatures: ■, 303.2 K; ●, 313.2 K; ▲, 323.2 K; ◀, 333.2 K; ▼, 343.2 K. WH2O is the mass fraction of water, and S is the separation factors of benzyl alcohol.
increase of the mass water and decreases with an increase in the temperature. An extraction separation of benzyl alcohol from binary benzyl alcohol + benzaldehyde mixtures by the extract agent water may be feasible. The lower temperature and higher content of water might be the optimal conditions. The detailed operation condition will be studied in detail in our ongoing work.
4. CONCLUSIONS Liquid−liquid equilibrium (LLE) data for the ternary water + benzyl alcohol + benzaldehyde have been measured at (303.2 to 343.2) K under atmospheric pressure. The reliability of the experimental LLE data has been checked according to the Othmer−Tobias and the Hand correlations. The experimental data were correlated by the NRTL and UNIQUAC activity coefficient models. The predicted values by NRTL and UNIQUAC method show good consistency with the measured data. The distribution coefficients and separation factors were used to discuss the ability of the solvent to extract benzyl alcohol. The results show that the separation factor of benzyl alcohol increased with increasing mass of water and decreased with increasing temperature. The extraction separation of benzyl alcohol from binary benzyl alcohol + benzaldehyde mixtures by the extract agent water may be feasible. The obtained results might be used in the separation process for the ternary system water + benzyl alcohol + benzaldehyde.
■
Standard uncertainty u is u(T) = 0.1 K.
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. 2811
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Funding
The project was granted financial support from Key S&T Special Project of Zhejiang Province (2012C13007-2) and the Fundamental Research Funds for the Central Universities. Notes
The authors declare no competing financial interest.
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