Vapor–Liquid Equilibrium for the 1,1,1-Trifluorotrichloroethane +

Vapor–liquid equilibrium (VLE) data for binary mixture of sulfuryl chloride and 1,1,1-trifluorotrichloroethane at atmospheric pressure were measured...
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Vapor−Liquid Equilibrium for the 1,1,1-Trifluorotrichloroethane + Sulfuryl Chloride System at 101.3 kPa Shuhan Chen,† Zongbi Bao,*,† Zhengzhang Lü,‡ Yiwen Yang,† Weiguo Xu,‡ Zhongmin Chen,‡ Qilong Ren,† Baogen Su,† and Huabin Xing† †

Key Laboratory of Biomass Chemical Engineering of the Ministry of Education, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China ‡ Zhejiang Chemical Industry Research Institute Co., Ltd., Hangzhou 310023, China ABSTRACT: Vapor−liquid equilibrium (VLE) data for binary mixture of sulfuryl chloride and 1,1,1-trifluorotrichloroethane at atmospheric pressure were measured with a double-phase circulation still. The experimental VLE data were correlated well with the Wilson, the nonrandom two-liquid (NRTL), and the universal quasichemical activity coefficient (UNIQUAC) models, respectively. From the correlation results, it is revealed that there is no azeotrope presented in the binary system. All of the experimental VLE data passed the thermodynamic consistency tests performed by the Herington and the Van Ness methods.

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INTRODUCTION

separating the mixture based on the difference in the volatility of components for a liquid mixture. VLE information is extremely important to process design and control of the distillation column for a practical distillation process. Therefore, the objective of this work is to report the VLE data of the binary system containing sulfuryl chloride and 1,1,1-trifluorotrichloroethane. The VLE data are further modeled and validated by thermodynamic models as well.

Trifluoroacetyl chloride (TFAC) is a useful starting material for the production of agricultural chemicals or pharmaceuticals, since it can readily react with amines or alcohols to produce amides or esters. TFAC can also be hydrolyzed to obtain trifluoroacetic acid that is popularly used as a strong acid in peptide synthesis and other organic synthesis to remove the tbutoxycarbonyl protecting group. It has been well established that TFAC can be synthesized in good yield by the reaction of SO3 with 1,1,1-trifluorotrichloroethane under reflux in the presence of mercury sulfates as catalyst. In the process of producing TFAC described by U.S. Pat. No. 3,725,475,1 a great amount of sulfuryl chloride could also be formed as byproduct in the reaction of SO3 with 1,1,1-trifluorotrichloroethane. Sulfuryl chloride is a valuable chemical and can be used as a chlorinating reagent for the chlorinations of ketones and aldehydes, as well as of several other substrates containing other functional groups.2 Besides, sulfuryl chloride is often used as a source of chlorine. As it is a pourable liquid, it is considered more convenient than Cl2 to measure, store, and dispense. The potentialities of this versatile reagent are not limited to its use as a chlorinating and sulfonating agent. The acylation of alcohols and amines, the conversion of carboxylic acid salts to acid chlorides and anhydrides, and the facilitation of various condensation reactions are among the better-known applications of sulfuryl chloride.3 The recovery of sulfuryl chloride as a byproduct in the production of TFAC seems meaningful and economical in reducing the process cost. However, sulfury chloride generally coexists with the unreacted 1,1,1-trifluorotrichloroethane in the reaction mixture. Rectification is a well-established method of © 2013 American Chemical Society

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EXPERIMENTAL SECTION

Materials. All chemicals used were of analytical grade and purchased from commercial sources. More detailed information about the chemicals is summarized in Table 1. Sulfuryl chloride, acetone, and ethanol were supplied by Aladdin Reagent (Shanghai, China), and 1,1,1-trifluorotrichloroethane was kindly provided by Sinochem Lantian, Co., Ltd. (Shangyu, China). Acetone and ethanol were further pretreated by the dehydrated 4A zeolite from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China) to remove the trace water. Sulfuryl chloride was used after further distillation. The purity of each chemical was checked by gas chromatography (GC) and confirmed by determining each boiling point. Boiling points at 101.3 kPa were measured by a double-phase circulation equilibrium apparatus as shown in Figure 1, which was equipped with a calibrated mercury thermometer. The uncertainty of the temperature measurements

Received: June 7, 2013 Accepted: December 12, 2013 Published: December 27, 2013 16

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Table 1. Material Description and Boiling Point (Tb) of Pure Components Tb/K chemical name

CAS number

commercial source

purity

this work

lit

acetone ethanol sulfuryl chloride 1,1,1- trifluorotri chloroethane

67-64-1 64-17-5 7791-25-5 354-58-5

Aldrich Aldrich Aldrich SinoChem

99 % 99 % > 98 % > 99 %

329.37 351.45 342.60 319.15

329.265 351.445 3416/342.557 319.28

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RESULTS AND DISCUSSION Experimental Reliability Test. To verify the performance of the modified Rose still, the VLE data for the acetone−ethanol

Table 2. Experimental Vapor−Liquid Equilibrium Data for Acetone (1) + Ethanol (2) at 101.3 kPaa

Figure 1. The scheme of the improved Rose equilibria still: 1, heating column; 2, liquid sample connection; 3, a precise mercury thermometer; 4, condenser; 5, liquid coolant; 6, connected to glass drying tower; 7, vapor (cooled to liquid) sample connection.

a

T/K

x1

y1

γ1

γ2

329.37 330.15 331.71 332.80 334.09 335.31 336.88 338.49 340.68 343.14 345.41 346.97 351.45

1.000 0.891 ± 0.004 0.743 ± 0.002 0.659 ± 0.002 0.564 ± 0.001 0.495 ± 0.003 0.402 ± 0.004 0.326 ± 0.004 0.240 ± 0.001 0.166 ± 0.001 0.110 ± 0.001 0.076 ± 0.002 0

1.000 0.933 ± 0.002 0.842 ± 0.004 0.790 ± 0.001 0.735 ± 0.001 0.680 ± 0.002 0.624 ± 0.002 0.560 ± 0.002 0.474 ± 0.003 0.391 ± 0.002 0.291 ± 0.002 0.227 ± 0.002 0

1.000 1.088 1.106 1.175 1.198 1.256 1.329 1.387 1.560 1.526 1.712 1.754 1.000

1.000 1.337 1.317 1.148 1.140 1.101 1.051 1.040 1.007 1.020 1.004 1.008 1.000

Standard uncertainties μ, are μ(T) = 0.15 K, μ(P) = 0.4 kPa, n

was within 0.15 K. As seen in Table 1, the experimental boiling points showed good agreement with the literature values. Apparatus and Procedure. The VLE data were measured using a modified Rose−Williams still,9,10 which is shown in Figure 1. The Rose equilibria still was proposed by A. Rose and E. T. Williams in 1955,11 so it was called the Rose−Williams Still. Later, it was improved by researchers in order to fix its inherent defects including the problem of large liquid volume and the issue of the dead angle. In this still, both the vapor and the liquid phases were continuously recirculating to provide intimate contact of the phases and ensure a rapid establishment of vapor− liquid equilibrium. At the beginning of the experiment, the chemicals were added into the boiling chamber and heated gradually. The liquid phases ascend through vapor−liquid lift pipe, and then spray on roughcast glass to enhance mass-transfer and heat-transfer. Equilibrium was assumed to be achieved when constant vapor temperature had been kept for more than 30 min, then samples from vapor and liquid were taken by microliter syringe. The equilibrium temperature was measured by a mercury thermometer as mentioned above. The pressure was kept equal to the ambient pressure and measured by a mercury barometer with an uncertainty of ± 0.4 kPa. The compositions of the vapor and liquid samples were analyzed by a Shimadzu GC-2010 gas chromatograph equipped with a thermal conductivity detector. The GC column was a Varian CP-PoraBOND capillary column (25 m × 0.32 mm × 5 μm). High-purity helium (99.999 %) was used as carrier gas. Each sample was analyzed at least three times to ensure the accuracy. The maximum uncertainty (μmax) of the composition of liquid samples was 0.008 in mole fraction.

μ(x) =

∑i = 1 (xi − x ̅ )2 n−1

μ(y) =

∑i = 1 (yi − y ̅ )2 n−1

n

Figure 2. Comparison between the experimental data and literature data for the acetone (1) + ethanol (2) system at 101.3 kPa: □, experimental; ■, ref 5.

system were measured and compared with other works.5 The results are shown in Table 2 and plotted in Figure 2. It can be seen that the experimental data of this work agree well with the reported data. Then the boiling point of analytical grade acetone, sulfuryl chloride, and 1,1,1-trifluorotrichloroethane that was 17

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Table 3. Experimental Vapor−Liquid Equilibrium Data for 1,1,1-Trifluorotrichloroethane (1) and Sulfuryl Chloride (2) at 101.3 kPaa

a

T/K

x1

y1

γ1

γ2

α12

319.15 319.85 320.51 321.92 322.81 323.74 324.60 325.75 326.47 327.56 328.02 329.23 331.50 332.16 333.88 334.40 335.65 336.90 337.88 338.4 338.91 342.6

1.000 0.939 ± 0.006 0.884 ± 0.008 0.775 ± 0.003 0.696 ± 0.003 0.642 ± 0.002 0.570 ± 0.001 0.523 ± 0.001 0.477 ± 0.001 0.388 ± 0.001 0.359 ± 0.002 0.318 ± 0.003 0.237 ± 0.002 0.205 ± 0.001 0.159 ± 0.003 0.155 ± 0.003 0.122 ± 0.003 0.088 ± 0.007 0.072 ± 0.002 0.060 ± 0.002 0.052 ± 0.002 0

1.000 0.962 ± 0.001 0.926 ± 0.003 0.858 ± 0.003 0.815 ± 0.003 0.770 ± 0.001 0.737 ± 0.001 0.690 ± 0.001 0.660 ± 0.007 0.606 ± 0.001 0.586 ± 0.001 0.549 ± 0.001 0.459 ± 0.001 0.431 ± 0.004 0.372 ± 0.004 0.345 ± 0.003 0.287 ± 0.001 0.247 ± 0.002 0.200 ± 0.002 0.181 ± 0.003 0.158 ± 0.002 0

1.000 1.058 1.058 1.067 1.096 1.088 1.141 1.123 1.151 1.256 1.292 1.315 1.373 1.466 1.545 1.449 1.475 1.694 1.629 1.737 1.744 1.000

1.000 1.389 1.386 1.297 1.208 1.236 1.139 1.160 1.129 1.073 1.060 1.040 1.030 1.014 0.997 1.017 1.020 0.994 1.005 0.998 0.999 1.000

1.638 1.638 1.754 1.926 1.861 2.109 2.027 2.128 2.431 2.527 2.607 2.722 2.943 3.130 2.873 2.901 3.402 3.223 3.452 3.455

Figure 4. Plot of relative volatility of 1,1,1-trifluorotrichloroethane (1) and sulfuryl chloride (2) against the liquid mole fraction of 1,1,1trifluorotrichloroethane at101.3 kPa: ■, experimental relative volatility; , correlated using the NRTL model.

sulfuryl chloride (2) at 101.3 kPa were measured and are shown in Table 3. A slightly positive deviation for the binary system can be observed. To verify the data quality, it is indispensable to test the thermodynamic consistency. For the binary system, the Herington method12 is usually used to verify the quality of all experimental data. The method suggests that

Standard uncertainties, μ(T) = 0.15 K, μ(P) = 0.4 kPa, n

μ(x) =

μ(y) =

∑i = 1 (xi − x ̅ )2

D=

n−1 n ∑i = 1 (yi

Sa − S b 100 Sa + S b

(1)

where Sa is the area of ln(γ1/γ2) − x1 above the x-axis, and Sb is the area of ln(γ1/γ2) − x1 under the x-axis.

2

− y̅ )

n−1

J = 150

Tmax − Tmin Tmin

(2)

Where Tmax and Tmin are the maximum and minimum temperature of the system, respectively. If (D − J) < 10, the isobaric VLE data can be considered to conform the thermodynamic consistency test. The values of D − J for the acetone (1) + ethanol (2) system and the 1,1,1trifluorotrichloroethane (1) + sulfuryl chloride (2) system are 2.1 and 0.6, respectively. However, the Herington area test is insufficient to validate the reliability of the isobaric vapor−liquid equilibrium data. The experimental data were also tested with the point-to-point test proposed by Van Ness et al.13 The system is considered to be thermodynamically consistent when the mean absolute deviation in the vapor mole fraction is less than 0.01, as recommended in the literature.14 The mean absolute deviations for the acetone (1) + ethanol (2) system and the 1,1,1-trifluorotrichloroethane (1) and sulfuryl chloride (2) system in the vapor phase mole fraction are 0.0036 and 0.0054, respectively. This indicates that the two systems are thermodynamically consistent. Correlation of Binary Systems. At VLE, the fugacity of each component i in the vapor phase should be equal to that in the liquid phase, thus

Figure 3. Plot of the experimental equilibrium temperature at 101.3 kPa against the mole fraction of 1,1,1-trifluorotrichloroethane (1) +sulfuryl chloride (2): ○, experimental vapor phase and ●, experimental liquid phase; , calculated liquid and vapor compositions from the Wilson model; ---, calculated liquid and vapor compositions from the NRTL model; ···calculated liquid and vapor compositions from the UNIQUAC model.

individually measured with this still is close to that from the reference. All results of the preliminary experiments indicate an acceptable performance of the still. Experiment Result and Consistency Test. The VLE data for a binary system of 1,1,1-trifluorotrichloroethane (1) and

fiV = fiL

(3)

yi φi V P = xiγif ioL

(4)

or

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Table 4. Physical Properties of Pure Componentsa

a

Tc

Pc

Vc

μ

compound

K

kPa

cm3/mol

Debye

Zc

ω

rb

qc

1,1,1-trifluoro-trichloroethane sulfuryl chloride

483.0 545.0

3320 4610

321 234

0.7405 1.8107

0.265 0.238

0.2467 0.4662

4.0461 3.5821

3.564 3.000

Taken from the databank of Aspen Properties. bVolume parameter of the UNIQUAC model. cSurface area parameter of the UNIQUAC model.

Table 5. Binary Interaction Parameters for 1,1,1-Trifluorotrichloroethane (1) and Sulfuryl Chloride (2) at 101.3 kPa model

parameters

Wilsonb

M12 = 0.85 M21 = −4.09 A12 = −3.70 A21 = 80 P12 = −2.59 P21 = 1.50

NRTLc,d UNIQUACe a

N12 (K) = −404.82 N21 (K) = 1293.52 B12 (K) = −1628.50 B21 (K) = −226.60 Q12 (K) = 807.22 Q21 (K) = −497.34

rmsd Δxa

rmsd Δya

0.033

0.031

0.038

0.120

0.032

0.032

rmsd, root mean square deviation: np

rmsdΔM = (1/np ∑ (Mkcalc − Mkexpt)2 )0.5 k=1 b

Wilson model: ⎡ Mij ⎤ ln Aij = ⎢Mij + ⎥ ⎣ T ⎦

NRTL model: τij = [Aij + Bij/T]. dThe value of α was fixed at 0.3 for each binary system. eUNIQUAC model:τij = [exp(Pij + Pij/T)].

c

Figure 6. Plot of estimated values of excess Gibbs free energy at 101.3 kPa against the mole fraction of 1,1,1-trifluorotrichloroethane (1). ○, experimental excess Gibbs free energy; , calculated excess Gibbs free energy from the NRTL model.

Figure 5. Plot of estimated values of vapor mole fraction of 1,1,1trifluorotrichloroethane at 101.3 kPa against liquid mole fraction of 1,1,1-trifluorotrichloroethane of the system 1,1,1-trifluorotrichloroethane (1) + sulfuryl chloride (2). ○, mole fraction of 1,1,1trifluorotrichloroethane; , calculated mole fraction of 1,1,1-trifluorotrichloroethane from the NRTL model.

γi =

yP i xiPiS

(5)

where P is the total pressure of equilibrium system; Psi is the vapor

where f, ϕ, y, P, x, and γ refer to the fugacity, fugacity coefficient, vapor composition, pressure, liquid composition, and activity coefficient, respectively. The superscripts V, L, and o represent the vapor phase, liquid phase, and standard state, respectively, and the subscript i stands for component i. As the pressure of the system is as low as ambient pressure, f oL i would approximately equal to Psi . Meanwhile, the vapor phase could be considered as ideal vapor phase under this pressure. This means ϕVi is approximately equal to unity. Thus, the activity coefficient of component i (γi), can be calculated by the following equation:

pressure of component i at equilibrium temperature, calculated by the Antoine equation, of which the Antoine constants of acetone, ethanol, sulfuryl chloride, and 1,1,1-trifluorotrichloroethane can be found from literature.5,15,16 The relative volatility of 1,1,1-trifluorotrichloroethane (1) and sulfuryl chloride (2) α12 was calculated by the following equation: α12 = 19

y1 /x1 y2 /x 2

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The values of α12 are shown in Table 3 and Figure 4. According to the magnitude of α12, it is not hard to conclude that the mixture of 1,1,1-trifluorotrichloroethane and sulfuryl chloride can be purified by rectification. Among the local composition models, the Wilson model,17 non-random two-liquid (NRTL) model,18 and the universal quasichemical activity coefficient (UNIQUAC) model19 are recommended for highly nonideal systems. The Wilson, NRTL, and UNIQUAC models were used to correlate the experimental VLE data. The value of αij in the NRTL model was fixed at 0.3. The physical properties of pure components used in the Wilson and UNIQUAC models are listed in Table 4.20 The data correlation was performed using ASPEN plus V7.1. In the data reduction process, the Britt and Luecke21 algorithm based on the maximum likelihood principle was adopted to minimize the following objective function:

isobaric VLE data. Good correlations were found for all three models, with the NRTL model yielding slightly better results.

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Corresponding Author

*E-mail: [email protected]. Tel.: 86-571-8795-1224. Fax: 86571-8795-2773. Funding

We are grateful for financial support from the National High Technology Research and Development Program of China (No. 2012AA040211), the Program for Zhejiang Leading Team of S&T Innovation (No. 2011R50002-02), and the National Natural Science Foundation of China (No. 20936005 and No. 21006083). Notes

2 ⎧⎡ calc expt ⎤2 ⎡ calc ⎪ pk − pkexpt ⎤ ⎥ + ⎢ Tk − Tk ⎥ F = ∑ ⎨⎢ ⎢⎣ ⎥⎦ ⎢ ⎥⎦ σp σT k=1 ⎪ ⎩⎣

The authors declare no competing financial interest.

np

⎡ y calc − ⎡ x calc − x expt ⎤ 1k ⎥ + ⎢ 1k + ⎢ 1k ⎢⎣ σx1 σy ⎢⎣ ⎥⎦ 1 2

■

⎤2 ⎫ y1expt ⎪ k ⎥ ⎬ ⎥⎦ ⎪ ⎭

REFERENCES

(1) Paucksch, H. Process of preparing fluorine containing perhalogencarboxylic acid fliorides or chlorides. US Pat. 3,725,475[P]. Apr. 3, 1973. (2) Masilamani, D.; Rogic, M. M. Sulfuryl chloride as a reagent for selective chlorination of symmetrical ketones and phenols. J. Org. Chem. 1981, 46 (22), 4486−4489. (3) Brawn, H. C. Sulfuryl chloride in organic chemistry. Ind. Eng. Chem. 1944, 39 (9), 785−791. (4) Richon, D. Experimental techniques for the determination of thermophysical properties to enhance chemical processes. Pure Appl. Chem. 2009, 81, 1769−1782. (5) Ku, H.-C.; Tu, C.-H. Isobaric vapor−liquid equilibria for mixtures of acetone, ethanol, and 2,2,4-trimethylpentane at 101.3 kPa. Fluid Phase Equilib. 2005, 231 (1), 99−108. (6) Kharasch, M. S.; Zavist, A. F. Reactions of atoms and free radicals in solution. XXIII: The peroxide-induced addition of sulfuryl chloride to 1alkenes. J. Am. Chem. Soc. 1951, 73, 964. (7) Luchinskii, G. P.; Likhacheva, A. I. Dichlorosulfuryl chlorosulfonate. Zh. Obshchei Khim. 1937, 7, 405−414. (8) Majer, V.; Svoboda, V. Enthalpies of vaporization of organic compounds: A critical review and data compilation. Blackwell Science: Oxford, UK, 1985, 300. (9) Yin, W.; Ding, S.-H.; Xia, S.-Q; Ma, P.-S.; Huang, X.-J.; Zhu, Z.-S. Cosolvent selection for benzene−cyclohexane separation in extractive distillation. J. Chem. Eng. Data 2010, 55 (9), 3274−3277. (10) Huang, X.-J.; Ma, P.-S.; Song, S.; Ma, B. J. Vapor−liquid equilibrium of N-formyl morpholine with toluene and xylene at 101.33 kPa. J. Chem. Eng. Data 2008, 53 (1), 252−255. (11) Rose, A.; Williams, E. T. Vapor liquid equilibrium self-lagging stills. Ind. Eng. Chem. 1955, 47 (8), 1528−1533. (12) Herington, E. F. G. Test of experimental isobaric vapor−liquid equilibrium data. J. Inst. Petrol. 1951, 37, 457−470. (13) Van Ness, H. C.; Byer, S. M.; Gibbs, R. E. Vapor liquid equilibrium. I. Appraisal of data reduction methods. AIChE J. 1973, 19, 238−244. (14) Fredenslund, A.; Gmehling, J.; Rasmussen, P. Vapor−Liquid Equilibria Using UNIFAC: A Group-Contribution Method; Elsevier: Amsterdam, The Netherlands, 1977. (15) Riedel, L. Bestimmung der thermischen Eigenschaften von Trifluor-Trichlorathan. Z. Gesamte Kaelte Ind. 1938, 45, 221−227. (16) Aubry, M.; Guiraud, R. Ebulliometry of the sulfuryl chloride− thionyl chloride binary system. Bull. Soc. Chim. France 1974, 9/10 (Pt.1), 1857−1858. (17) Wilson, G. M. Vapor−liquid equilibrium XI: A new expression for the excess free energy of mixing. J. Am. Chem. Soc. 1964, 86, 127−130. (18) Renon, H.; Prausnitz, J. M. Local compositions in thermodynamics excess functions for liquid mixtures. AIChE J. 1968, 14, 135− 144.

(7)

Where np is the number of data points. The superscripts of calc and expt represent the calculated and experimental values, respectively. The standard deviations (σ) of temperature and pressure are 0.15 K and 0.4 kPa, respectively. They were listed in Table 3 along with liquid and vapor compositions. The results of data correlation are given in Table 5, and graphical representations are shown in Figures 3 and 5. Figure 3 reveals that the calculated results from these three models almost overlap with the experimental measurements. Table 5 also shows that the deviations between the experimental and the calculated values are slight. All of these three models represent satisfactory VLE behavior for the binary system of sulfuryl chloride + 1,1,1trifluorotrichloroethane at 101.3 kPa. To understand the nonideality of the binary system investigated, the excess Gibbs free energies GE were calculated by using following equation: GE = RT (x1 ln γ1 + x 2 ln γ2)

AUTHOR INFORMATION

(8)

In Figure 6 the variation of excess Gibbs free energy with composition is shown for the liquid phase at temperatures from 319.85 to 338.91 K and a pressure of 103.3 kpa. It can be seen that although the system exhibits positive deviation from ideality, the values are very small, indicating that the behavior of the system is close to ideal at these conditions.

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CONCLUSION Isobaric VLE data have been determined experimentally for the binary system of acetone + ethanol system, and sulfuryl chloride + 1,1,1-trifluorotrichloroethane at 101.3 kPa over the entire composition range. The experimental data for the acetone− ethanol system agreed well with the literature data, indicating the reliability of the present experiment method. No azeotrope was observed for the binary system of sulfuryl chloride and 1,1,1-trifluorotrichloroethane at ambient pressure. The Herington and the van Ness methods were used to check the reliability of experimental results, and the system passed both thermodynamic consistency test criteria. The Wilson, NRTL, and UNIQUAC models were used to correlate the experimental 20

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(19) Abrams, D. S.; Prausnitz, J. M. Statistical thermodynamics of liquid mixtures: A new expression for the excess energy of partially or completely miscible systems. AIChE J. 1975, 21, 116−128. (20) Brelvl, S. W. Simple correlations for UNIQUAC structure parameters. Ind. Eng. Chem. Process Des. Dev. 1982, 21, 367−370. (21) Britt, H. I.; Luecke, R. H. The estimation of parameters in nonlinear implicit models. Technometrics. 1973, 15, 233−247.

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