Vapor–Liquid Phase Equilibrium of a Cyclohexene + Water +

Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

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Vapor−Liquid Phase Equilibrium of a Cyclohexene + Water + Cyclohexanol + Isophorone Quaternary System at 500 kPa Hui Tian,*,† Jinchao Sun,† Yupeng Du,† and Wenyou Xu*,†,‡ †

College of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, China Collaborative Innovation Center of Comprehensive Utilization of Light Hydrocarbon Resource, Yantai University, Yantai 264005, China

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‡

ABSTRACT: Cyclohexanol is an important intermediate for producing adipic acid and ε-caprolactame, as well as nylons. Furthermore, cyclohexene directly hydrated to cyclohexanol overcomes the shortcomings of the traditional methods and is attracting more and more attention, but due to the solubility of cyclohexene in water, it still suffers from rather low equilibrium conversion and a fairly slow reaction rate. The addition of isophorone can significantly increase the solubility of cyclohexene in the aqueous phase, and thus, it is appropriate as a cosolvent for the direct hydration of cyclohexene to cyclohexanol by extractive distillation. It is known from previous literature that cyclohexene hydration is under medium and high pressure. In this study, the vapor−liquid equilibrium (VLE) data for the vapor−liquid phase equilibrium of ternary systems cyclohexene + cyclohexanol + isophorone and quaternary systems cyclohexene + water + cyclohexanol + isophorone were measured at 500 kPa. The NRTL, Wilson, and UNIQUAC models were employed to correlate the binary VLE data of water−cyclohexene, water−cyclohexanol, water−isophorone, cyclohexene− cyclohexanol, cyclohexene−isophorone, and cyclohexanol−isophorone.

1. INTRODUCTION Cyclohexanol is an important intermediate for producing adipic acid and ε-caprolactame, as well as nylons.1−5 There are three commercial routes for producing cyclohexanol: (1) the oxidation of cyclohexane, (2) the hydrogenation of phenol, and (3) the direct hydration of cyclohexene. The third route using the direct hydration of cyclohexene proposed by researchers from Asahi Chemical Industry Co., Ltd., avoided most disadvantages associated with the previous processes, namely, for high energy demands, low selectivity, and low conversion. However, the slow reaction rate and fairly low equilibrium conversion hampered the broader application of the new process; thus, it is of great interest to investigate this process further to elucidate a more favorable commercial operation. In view of the problems of low conversion rate, poor operational safety, and the very low mutual solubility between cyclohexene and water in the cyclohexene hydration reaction, a new method for preparing cyclohexanol using reactive distillation technology was applied. Moreover, adding the cosolvent isophorone in the system improved the cyclohexene solubility in the aqueous phase and the reaction conversion rate. In order to obtain reliable thermodynamic data, vapor− © XXXX American Chemical Society

liquid equilibrium (VLE) data of the cyclohexene−cyclohexanol−isophorone ternary system and the cyclohexene + water + cyclohexanol + isophorone quaternary system were determined using data regression calculations of the binary system equilibrium data. This was used to establish the binary interaction parameters, which were used to provide the basic data for the calculation of the reaction distillation of the cyclohexene hydration process.6−8

2. EXPERIMENTAL SECTION 2.1. Materials. Cyclohexene, water, cyclohexanol, and isophorone were used in these experiments, and the specifications are given in Table 1. 2.2. Apparatus and Procedure. The experiments were carried out in a BCF-1 high-pressure vapor−liquid phase equilibrium still at 500 kPa controlled by a reactor control instrument, which includes an equilibrium chamber, a liquidphase sampling port, a heating bar, a vapor-phase sampling Received: April 3, 2018 Accepted: October 15, 2018

A

DOI: 10.1021/acs.jced.8b00273 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

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Table 1. Purities and Suppliers of the Chemicals List reagenta molecular formula CASRN source purity (mass fraction)

ENE

H2O

NOL

Table 2. Isobaric VLE Data and Activity Coefficients for the Ternary System ENE(1) + NOL(2) + IPHO(3) at 500 kPaa

IPHO

C6H10

H2O

C6H12O

C9H14O

110-83-8 Macklin, Shanghai 0.999

7732-18-5 made by ourselves 1.000

108-93-0 Macklin, Shanghai 0.998

78-59-1 Macklin, Shanghai 0.998

a

ENE - cyclohexene, H2O - water, NOL - cyclohexanol, IPHO isophorone.

port, and a condenser, as shown in Figure 1. The BCF-1 reactor is produced by Yantai Keli Chemical Equipment Co.,

T/K

x1

x2

y1

y2

427.6 433.9 434.7 435.8 439.8 443.8 446.5 448.5 454.2 459.7 460.9 469.0 472.4 477.9 484.5 493.9 506.7 517.0 527.4 532.5 539.5

0.819 0.828 0.805 0.753 0.746 0.728 0.696 0.609 0.542 0.516 0.513 0.450 0.385 0.332 0.285 0.145 0.105 0.080 0.059 0.049 0.038

0.172 0.164 0.147 0.141 0.137 0.124 0.105 0.082 0.070 0.059 0.055 0.050 0.043 0.030 0.021 0.047 0.042 0.036 0.029 0.025 0.021

0.97 0.968 0.968 0.958 0.955 0.954 0.953 0.953 0.952 0.950 0.949 0.942 0.941 0.930 0.917 0.695 0.597 0.511 0.418 0.372 0.305

0.029 0.022 0.022 0.030 0.033 0.024 0.025 0.025 0.025 0.027 0.024 0.032 0.032 0.042 0.048 0.057 0.063 0.064 0.060 0.057 0.051

a

Standard uncertainties: u(x1) = 0.002, u(x2) = 0.002, u(y1) = 0.002, u(y2) = 0.002, u(T) = 0.1 K, u(P) = 1 kPa. Figure 1. Experimental flowchart. 1 - nitrogen bottle; 2 - advection pump; 3 - autoclave; 4 - heating jacket; 5 - magnetic stirrer; 6 - reactor control cabinet; 7 - thermocouple; 8 - pressure port.

Table 3. Isobaric VLE Data and Activity Coefficients for the Quaternary System ENE(1) + H2O(2) + NOL(3) + IPHO(4) at 500 kPaa T/K

x1

x2

x3

y1

y2

y3

429.5 430.3 431.4 435.4 439.4 442.1 444.6 450.3 455.8 457.0 465.1 468.5 474.0 480.6 484.6 487.7 490.9 494.0 502.8 519.0 525.8 529.9

0.345 0.335 0.314 0.311 0.303 0.290 0.254 0.226 0.215 0.214 0.187 0.160 0.138 0.119 0.032 0.030 0.027 0.026 0.020 0.011 0.009 0.008

0.314 0.281 0.270 0.263 0.238 0.201 0.158 0.134 0.113 0.106 0.096 0.083 0.058 0.040 0.022 0.020 0.019 0.017 0.013 0.007 0.005 0.005

0.249 0.260 0.258 0.224 0.214 0.262 0.325 0.333 0.307 0.296 0.321 0.357 0.368 0.392 0.092 0.087 0.083 0.078 0.066 0.087 0.076 0.069

0.454 0.432 0.410 0.389 0.373 0.369 0.357 0.348 0.336 0.315 0.293 0.279 0.259 0.253 0.225 0.215 0.205 0.195 0.167 0.096 0.080 0.071

0.38 0.361 0.343 0.325 0.312 0.309 0.298 0.291 0.281 0.263 0.245 0.234 0.216 0.212 0.232 0.22 0.209 0.198 0.168 0.101 0.083 0.073

0.067 0.076 0.079 0.071 0.056 0.061 0.066 0.074 0.043 0.063 0.093 0.114 0.12 0.117 0.187 0.184 0.18 0.176 0.161 0.224 0.205 0.191

Ltd., and is equipped with relevant intelligent controllers. The controller uses intelligent digital control instruments to provide data acquisition and control of motor rotation speed, reaction temperature, and pressure inside the reactor. The internal volume was around 1 L, of which about 0.6 L was occupied by the liquid. In order to ensure the equilibrium established, both the vapor and the liquid phases continuously circulated when the temperature remained constant for 30 min during the experimental process. The sample amount was determined as 0.1−0.2 mL, in order to decrease the influence on the equilibrium system, which was negligible compared with the liquid volume of 0.6 L.9,10 The pressure was controlled by a Fischer M101 system, and the pressure still was controlled at 500 ± 1 kPa by a pressure relief valve. First flushed with 500 kPa of nitrogen, the liquid starts to generate steam after heating, and the pressure continues to rise through the pressure relief valve to maintain the pressure at 500 kPa.11,12 2.3. Sample Analysis. The amples were analyzed using a gas chromatograph (GC)-2010 (Shimadzu Enterprise Management (China) Co., Ltd.) equipped with a flame ionization detector. The injection volume of each sample into the GC was 0.6 μL. In order to reduce errors, the final composition of the samples was determined as the average of three replication results. The standard uncertainty of the compositions was 0.002 of the mass fraction.

Standard uncertainties: u(x1) = 0.002, u(x2) = 0.002, u(x3) = 0.002, u(y1) = 0.002, u(y2) = 0.002, u(y3) = 0.002, u(T) = 0.1 K, u(P) = 1 kPa.

3. CALCULATION PROCEDURE AND RESULTS AND DISCUSSION 3.1. Experimental Data. The VLE data for the ternary system cyclohexene + cyclohexanol + isophorone and the quaternary system cyclohexene + water + cyclohexanol +

isophorone were measured with a high-pressure reactor at 500 kPa in this work, the experimental data for which are listed in Table 2 and Table 3.

a

B

DOI: 10.1021/acs.jced.8b00273 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

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temperature T, in units of Pa, and T is for the temperature in units of K.16 The Antoine equations for each component in the cyclohexene hydration reaction system containing isophorone as a cosolvent are reported in Table 4. Among them, the Antoine equations for cyclohexene, water, and cyclohexanol were derived from the literature, and the Antoine equation of isophorone was derived from the database.17 3.3. Data Regression. The binary interaction parameters are important to predict the VLE of the quaternary system cyclohexene + water + cyclohexanol + isophorone. In this work, the experimental data of the system were regressed using the nonrandom two-liquid (NRTL), Wilson, and UNIversal QUAsi Chemical(UNIQUAC) methods to obtain the corresponding interaction parameters of the binary system. The NRTL, Wilson, and UNIQUAC models were employed by Aspen Plus, and the correlated binary interaction parameters by the NRTL, UNIQUAC, and Wilson models are listed in Table 5.

Table 4. Antoine Equation of the Cyclohexene Hydration Reaction Systema Antoine equation psat ENE psat H2O

= exp[15.8243 − 2813.53/(T − 49.98)] = exp[18.3036 − 3816.44/(T − 46.13)]

−6 2 psat NOL = exp[119.8 − 11155/T − 13.71 ln T + 3.69 × 10 T ] psat = exp[83.031−8112.6/T − 9.51171 ln T + 8.18 × 10−3T] IPHO

a

sat sat sat The units of psat ENE and pH2O are mmHg, the units of pNOL and pIPHO are Pa, and the units of temperature T are K.

3.2. The VLE Model. The activity coefficient of the compositions can be calculated using the following equation:13,14 γi = φî v yP /{xiφi sPi s exp[(P − Pi s)Vi L /(RT )]} i (i = 1, 2, ..., N )

(1)

The Poynting factor exp[(P − is approximately equal to 1 at low pressure. Therefore, eq 1 can be simplified to Pis)ViL/RT]

γi = φî v yP /(xiφi v Pi s) i

4. CONCLUSIONS The isobaric VLE data for the ternary system cyclohexene + cyclohexanol + isophorone and the quaternary system cyclohexene + water + cyclohexanol + isophoroneat at 500 kPa were measured in a vapor−liquid equilibrium still with circulation. The NRTL, Wilson, and UNIQUAC models were employed to correlate the binary VLE data of water− cyclohexene, water−cyclohexanol, water−isophorone, cyclohexene−cyclohexanol, cyclohexene−isophorone, and cyclohexanol−isophorone.

(2) s

The saturated vapor pressure Pi is calculated by the following Antoine equation15 ln Pi sat = C1i + C2i /(T + C3i) + C4iT + C5i ln T + C6iT C 7i

(3)

where C1i, C2i, C3i, C4i, C5i, C6i, and C7i are physical constants, Pisat is the pure liquid saturated vapor pressure at the

Table 5. Binary Interaction Parameters for the Binary Systems at 500 kPa binary interaction parameters aij

model

a

NRTLa Wilsonb UNIQUACc

1.0635 0.1814 −9.6538

NRTL Wilson UNIQUAC

1.1003 −7.1525 −19.4555

NRTL Wilson UNIQUAC

4.5738 9.2658 −14.8185

NRTL Wilson UNIQUAC

2.5118 −0.0310 10.8908

NRTL Wilson UNIQUAC

1.6816 0.7902 −1.3116

NRTL Wilson UNIQUAC

4.7338 6.0425 2.3378

NRTL: τij = aij +

bij T

,

aji

bij

water (i)−cyclohexene (j) −12.5405 94.4537 0.0096 442.4241 12.7824 3962.7117 water (i)−cyclohexanol (j) −5.9154 243.9621 −5.7834 3200.6243 −1.6855 −8987.3808 water (i)−isophorone (j) −5.7044 221.3692 −17.4296 −4300.4826 4.8393 −8691.1562 cyclohexene (i)−cyclohexanol (j) 11.9325 −298.1759 −0.4141 168.4286 −18.3159 −5213.6136 cyclohexene (i)−isophorone (j) 0.4756 217.1610 0.3444 −126.5798 −0.1210 −426.5237 cyclohexanol (i)−isophorone (j) −19.9471 −151.8371 7.2122 −3382.4607 3.7129 −939.1980

(

αij = 0.3. bWilson: ln Aij = exp aij +

bij T

).

(

c

UNIQUAC: τij = exp aij + C

bji

αij

4442.9533 71.7794 −4954.9291

0.3

2029.2308 3114.1631 1909.2452

bij T

1463.1783 −7936.5382 −1733.6581

0.3

−6504.0134 155.2772 8482.5568

0.3

−993.5183 −460.4689 536.7860

0.3

9607.7368 −3723.9668 −2185.3599

0.3

). DOI: 10.1021/acs.jced.8b00273 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

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algorithm for vapor-liquid equilibrium data. J. Chem. Eng. Data 2010, 55, 3631−3640.

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Hui Tian: 0000-0002-1324-9302 Funding

The authors acknowledge the Natural Science Foundation of Shandong Province, China (ZR2017QB006), the Colleges and universities in Shandong Province science and technology projects (J16LC22), and the Focus on research and development plan in Yantai city (2018XSCC038). Notes

The authors declare no competing financial interest.

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DOI: 10.1021/acs.jced.8b00273 J. Chem. Eng. Data XXXX, XXX, XXX−XXX