Fluid Phase Equilibria 341 (2013) 30–34

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Fluid Phase Equilibria

j ournal homepage: www.elsevier.com/locate/fluid

Investigation on vapor–liquid equilibrium for

2-propanol + 1-butanol + 1-pentanol at 101.3 kPa

∗

Juan Wang, Zonghong Bao

College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China

a r t i c l e i n f o a b s t r a c t

Article history: Isobaric vapor–liquid equilibrium (VLE) data for 2-propanol + 1-butanol, 2-propanol + 1-pentanol, 1-

Received 26 September 2012

butanol + 1-pentanol and 2-propanol + 1-butanol + 1-pentanol were measured at 101.3 kPa by using an

Received in revised form 5 December 2012

improved Rose still. All the binary VLE data have passed the traditional area test proposed by Herington.

Accepted 18 December 2012

The interaction parameters for the Wilson, NRTL and UNIQUAC equations were determined by regress-

Available online 7 January 2013

ing the binary VLE data. The prediction for ternary system was given by using the three pairs of binary

parameters correlated. And the ternary data predicted agreed well with the experiment data. Keywords: © 2013 Elsevier B.V. All rights reserved. 2-Propanol 1-Butanol 1-Pentanol

Vapor–liquid equilibrium

1. Introduction 1-pentanol and ternary mixture of 2-propanol + 1-butanol + 1-

pentanol were obtained at 101.3 kPa. The experimental values were

Currently the international oil price has been rising, and the correlated by the Wilson, NRTL and UNIQUAC equations, in which

domestic oil resources are increasingly scarce. All these lead to a the binary parameters were obtained through the maximum like-

trend about producing mixed alcohols by using coal. The C1–C8 lihood. The quality of the experimental binary values was veriﬁed

mixed alcohols were produced at the same time by a new coal by the Herington method [5].

chemical synthesis technology in a set of device. This production

has already begun to accelerate the domestic industrial process [1].

2. Experimental

Mixed alcohols can continue to conduct multi-fractionations

and result in a series of single alcohol include methanol, ethanol,

2.1. Chemicals

propanol, etc. But the vapor–liquid equilibrium (VLE) data play

an important role in the design and optimized operations of

The physical properties of chemical reagents used are given

distillation processes. So far many useful VLE data among the

in Table 1. Methanol and 1-pentanol were supplied by Shanghai

mixed alcohols have been presented. However, for 2-propanol + 1-

Lingfeng Chemical Co. Ltd. 2-Propanol and 1-butanol were supplied

pentanol system, there is only one report about VLE data in 313.15 K

by Shanghai Shenbo Chemical Co. Ltd. Methanol and 2-propanol

[2], and no report is in isobaric condition. To 1-butanol + 1-pentanol

were used without further puriﬁcation. 1-Butanol and 1-pentanol

system, data in low pressure are available [3], but they may not

were further puriﬁed by distillation in a column. All the reagents

meet the requirement of design calculations. As for 2-propanol + 1-

were dried on 0.4 nm molecular sieves and degassed by ultrasound

butanol system, Wang et al. [4] determined temperature and

before use. The purity of chemicals used was checked by the gas

liquid phase mole fraction in 101.3 kPa without giving vapor-

chromatography equipped with a thermal conductivity detector

phase mole fraction. Therefore, it is necessary to measure the VLE

and a stainless steel column. The refractive indices and normal boil-

data for 2-propanol + 1-butanol, 2-propanol + 1-pentanol, and 1-

ing points were measured by the WYA Abbe refractometer and the

butanol + 1-pentanol at atmospheric pressure condition.

improved Rose still, respectively.

In this paper, isobaric VLE results for binary mixture of

2-propanol + 1-butanol, 2-propanol + 1-pentanol and 1-butanol +

2.2. Apparatus and procedures

In this study, the VLE data were obtained with a glass recircula-

∗

tion apparatus called improved Rose still described by Zhang et al.

Corresponding author. Tel.: +86 025 83587190.

E-mail address: [email protected] (Z. Bao). [7]. A mercury thermometer was used to measure the equilibrium

0378-3812/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ﬂuid.2012.12.020

J. Wang, Z. Bao / Fluid Phase Equilibria 341 (2013) 30–34 31

Table 1

Physical properties of experimental materials.

Compound Purity (mass %) Water (mass %) nD (298.15 K) Tb/K (101.3 kPa)

Experiment Literature [6] Experiment Literature [6]

Methanol >99.5 <0.1% 1.3288 1.3286 337.69 337.66

2-Propanol >99.7 <0.1% 1.3776 1.3775 355.50 355.55

1-Butanol >99.6 0.1% 1.3995 1.3993 390.86 390.85

1-Pentanol >99.6 0.1% 1.4097 1.4099 411.10 411.15

Note: u(w) = ±0.001, u(nD) = ±0.0001, u(Tb) = ±0.01 K.

Table 2

temperature with an accuracy of temperature of 0.1 K, and con-

VLE data for 2-propanol (1) + 1-butanol (2), 2-propanol (1) + 1-pentanol (2), and 1-

ducted exposed neck correction to obtain the true temperature. The

butanol (1) + 1-pentanol (2) system at 101.3 kPa.

experiment pressure was controlled by a constant pressure system

T/K x y T/K x y

(a vacuum pump, a U-tube, and a buffer tank), and the precision 1 1 1 1

±

was within 133 Pa. 2-Propanol (1) + 1-butanol (2)

In the experiments, all the analytical work was carried out by 390.86 0 0 370.75 0.4002 0.7221

389.12 0.0227 0.0672 369.13 0.4471 0.7615

a gas chromatograph (GC6890, supplied by Shandong Lunan Rui-

387.53 0.0474 0.1362 367.77 0.4938 0.7954

hong instruments company), which was equipped with a ﬂame

385.95 0.0744 0.2067 366.51 0.5341 0.8218

ionization detector (FID). The composition of vapor phase and liq-

384.15 0.1062 0.2825 364.99 0.5840 0.8526

uid phase was calculated by the area normalization method, which 382.96 0.1299 0.3357 363.60 0.6307 0.8768

381.80 0.1465 0.3750 362.17 0.6836 0.9015

can accurate to 0.001. The GC column was 30 m long and 0.32 mm

379.00 0.2023 0.4759 360.67 0.7333 0.9221

in diameter silica capillary column packed with OV-1701. The car-

376.05 0.2693 0.5731 359.27 0.7957 0.9448

rier gas was high purity nitrogen, and head pressure was 400 kPa.

374.00 0.3170 0.6373 357.16 0.9052 0.9775

The injector and detector temperature of column were 473.15 K 373.65 0.3255 0.6480 355.50 1 1

and 493.15 K, respectively.

2-propanol (1) + 1-pentanol (2)

Methanol + 2-propanol system as a checking system was mea-

411.10 0 0 380.36 0.3302 0.7905

sured ﬁrst. The VLE data at 101.3 kPa and comparisons to literature 408.68 0.0156 0.0741 379.45 0.3494 0.8072

406.51 0.0315 0.1499 377.00 0.3956 0.8405

are shown in Fig. 1. The results matched very well with previous

404.91 0.0495 0.2355 374.75 0.4364 0.8644

literature and this result gives us a conﬁdence of our instruments

402.10 0.0682 0.2973 372.45 0.4821 0.8861

and analysis method.

400.42 0.0854 0.3565 371.03 0.5105 0.8990

398.32 0.1016 0.4056 367.88 0.5908 0.9275

395.97 0.1250 0.4684 366.57 0.628 0.9385

3. Results and discussion

392.48 0.1615 0.5509 363.69 0.7059 0.9573

390.25 0.1895 0.6088 361.67 0.7645 0.9685

3.1. VLE model and experiment data 388.14 0.2141 0.6498 359.47 0.8324 0.9798

385.00 0.2579 0.7155 357.45 0.9032 0.9895

383.55 0.2794 0.7398 355.50 1 1

The VLE results of binary system (2-propanol + 1-butanol,

2-propanol + 1-pentanol, and 1-butanol + 1-pentanol) and ternary 1-butanol (1) + 1-pentanol (2)

411.10 0 0 400.17 0.4836 0.6405

system (2-propanol + 1-butanol + 1-pentanol) are shown in

410.00 0.0440 0.0741 398.60 0.5369 0.6895

Tables 2 and 3. The activity coefﬁcient of pure component was

409.70 0.0537 0.0900 397.88 0.5796 0.7297

calculated by:

408.00 0.1046 0.1725 396.57 0.6488 0.7920

407.50 0.1383 0.2245 395.93 0.6913 0.8250

p

V L 406.04 0.1906 0.3065 395.13 0.7336 0.8604

v sat s i 404.96 0.2408 0.3763 393.83 0.8022 0.8997

=

pyiϕi xiipi ϕi exp dp (1)

RT 404.31 0.2936 0.4378 393.13 0.8579 0.9290

s

p 403.20 0.3394 0.4950 392.02 0.9115 0.9599

i

401.74 0.3833 0.5366 390.86 1 1

400.90 0.4308 0.5875

356 Note: u(T) = ±0.01 K, u(x) = ±0.001, u(y) = ±0.001. 354

352 Table 3

VLE data for 2-propanol (1) + 1-butanol (2) + 1-pentanol (3) ternary system at

350 101.3 kPa.

348 T/K x1 x2 y1 y2 1 2 3 /K

T

346 375.71 0.3031 0.6489 0.5264 0.3045 1.0056 1.0199 1.0343

378.07 0.2648 0.6172 0.4775 0.3047 1.0099 1.0259 1.0383

344

381.30 0.2184 0.5675 0.4341 0.3125 1.0102 1.0227 1.0354

342 383.30 0.1911 0.5321 0.4084 0.3174 1.0136 1.0240 1.0390

385.91 0.1595 0.4855 0.3722 0.3189 1.0183 1.0249 1.0408

340

388.36 0.1341 0.4399 0.3396 0.3179 1.0152 1.0243 1.0419

338 391.37 0.1068 0.3818 0.3002 0.3132 1.0072 1.0253 1.0374

395.79 0.0428 0.1755 0.3980 0.4846 1.0100 1.0259 1.0393

336 397.46 0.0373 0.1599 0.3404 0.4378 1.0047 1.0236 1.0398

0.0 0.2 0.4 0.6 0.8 1.0

399.49 0.0281 0.1285 0.2881 0.3973 1.0097 1.0250 1.0365

x , y

1 1 401.17 0.0216 0.1036 0.2429 0.3547 1.0086 1.0263 1.0367

403.04 0.0151 0.0759 0.1974 0.3060 1.0018 1.0244 1.0343

± ± ±

Fig. 1. Comparisons of T–x1–y1 diagram for methanol + 2-propanol between exper- Note: u(T) = 0.01 K, u(x) = 0.001, u(y) = 0.001.

iment and literature at 101.3 kPa. , Ref. [8]; ଝ, Ref. [9]; ᭹, this work.

32 J. Wang, Z. Bao / Fluid Phase Equilibria 341 (2013) 30–34

Table 4

The physical properties of pure component.

Parameters 2-Propanol 1-Butanol 1-Pentanol

a

Tc /K 508.3 563.0 588.1

a

Pc /MPa 4.764 4.414 3.897

a 3 −1

Vc /cm mol 222 274 326

a

Zc 0.25 0.258 0.26

b

RD /Å 2.726 3.225 3.679

c

/D 1.679 1.679 1.799

d

q 2.51 3.052 3.592

d

r 2.78 3.4543 4.1287

a

The Antoine coefﬁcients

A 6.40823 6.54172 6.3975

B 1107.303 1336.026 1337.613

−

C 103.944 −96.348 −106.567

T/K 358–461 323–413 326–411

Note: a

Ref. [11]. b

Ref. [12]. c

Ref. [6]. d

Ref. [13].

where xi is the liquid-phase mole fraction of component i, yi is the

vapor-phase mole fraction of component i, p is the total pressure, i

v s

is the activity coefﬁcient of component i, ϕi and ϕi are the fugacity

coefﬁcient and the fugacity coefﬁcient at saturation of component

sat

i. The saturated vapor pressure pi was calculated by the Antoine equation:

s B

lg p (kPa) = A − (2)

T(K) + C

p

L

where exp (Vi /RT)dp is called Poynting coefﬁcient. It can be con-

ps

i

sidered to be 1 at the moderate or low pressure conditions. So Eq

(1) can be written:

v sat s = pyiϕi xiipi ϕi (3) v where ϕi is: ⎧ ⎫ ⎨ ⎬

v p 1 ln ϕ = B + [y y (2ı − ı )] (4) i RT ⎩ ii 2 i k ji jk ⎭

j k

ıji and ıjk can be given by:

= = − −

ıji ıij 2Bji Bjj Bii (5)

= = − −

ıjk ıkj 2Bjk Bjj Bkk (6)

Fig. 2. Relationship between activity coefﬁcients ( 1) and liquid-phase mole

fractions (x1) for (a) 2-prapanol (1) + 1-butanol (2) system, (b) 2-prapanol (1) + 1-

where Bii, Bjj and Bkk are the second term of the virial state equation;

pentanol (2) system, and (c) 1-butanol (1) + 1-pentanol (2) system. ᭹, experimental

Bji and Bjk are the cross second term of the virial state equation,

1–x1, —, correlated 1–x1; , experimental 2–x1, - - -, correlated 2–x1.

which are calculated by the Hayden and O’Connell method [10]. All

the physical properties required in this calculation are shown in

Table 4. The relationship between liquid-phase mole fractions and

activity coefﬁcients is also displayed in Fig. 2. 3.2. Correlation for binary VLE data

We carried out Herington method which based on Gibbs-

Duhem equation to check the thermodynamic consistency of In this research, the VLE data was correlated with the Wil-

binary system. The method includes two parameters (D and J), son, NRTL, and UNIQUAC equations, respectively. The interaction

an area function and a temperature function, respectively. If parameters of binary system were obtained by iterative solution,

the value of (D − J) is less than 10, the isobaric VLE data pass and they were based on the maximum likelihood of objective func-

the thermodynamic consistency test. In this research, the results tion:

(D − J) for 2-propanol + 1-butanol, 2-propanol + 1-pentanol and 1-

N

butanol + 1-pentanol system are 3.37, 0.72 and 2.25, respectively.

cal exp 2 cal exp 2

= − + −

Obviously, all the binary isobaric data passed the thermodynamic F [( ) ( ) ] (7) i i n j j n consistency test. n

J. Wang, Z. Bao / Fluid Phase Equilibria 341 (2013) 30–34 33

Table 5 410

Regression parameters in equations for activity coefﬁcients. 405

−1 −1

Equation A12/(J mol ) A21/(J mol ) y1 T/K 400

2-Propanol(1) + 1-butanol(2) 395

Wilson −35.22 56.87 0.0031 0.20

390

NRTL (˛ = 0.3) 4151.27 −3027.73 0.0029 0.21

UNIQUAC 2512.93 −1793.08 0.0032 0.20 385 /K

T

2-Propanol(1) + 1-pentanol(2) 380

Wilson 26.90 −25.49 0.0037 0.26

375

NRTL (˛ = 0.3) −1966.54 1905.90 0.0040 0.40

UNIQUAC −568.78 542.39 0.0049 0.49 370

1-Butanol(1) + 1-pentanol(2)

365

Wilson −133.80 648.30 0.0054 0.25

NRTL (˛ = 0.3) 3697.42 −2967.98 0.0047 0.21 360

UNIQUAC 2305.76 −1754.10 0.0048 0.20

355

0.0 0.2 0.4 0.6 0.8 1.0

Note: Wilson, A12 = (12–11); NRTL, A12 = (g12–g22); UNIQUAC, A12 = (u12–u22). x 1 , y1

cal exp

Fig. 4. T–x –y diagram for 2-prapanol (1) + 1-pentanol (2) at 101.3 kPa. ᭹, experi-

where i , i are the activity coefﬁcients calculated by correla- 1 1

mental data; —, Wilson regression p(x = 0) = 101.39 kPa, p(x = 1) = 101.20 kPa.

tion and the activity coefﬁcients calculated by Eq. (3). N refers to 1 1

the number of experiment data.

The average deviations (y and T) were expressed as:

The D and Dmax can be calculated by (11) and (12).

N cal exp | − | = y y i 1 i i N y = (8)

N

= + − D (xic xid) (ln id ln ic) (11) N

| − | = i=1 Tcal Texp i 1

T = (9)

N

The regression parameters and average deviations (y and T) N

1 1 1 1

= + + + + are listed in Table 5. In Table 5, the deviation whether in vapor- Dmax (xic xid) x

xic yic xid yid

phase mole fraction or in temperature is very close among three i=1

models, so we only showed the comparisons between experiment

N

data and the Wilson model regression results in Figs. 3–5.

+

| − | 2 ln id ln ic x

i=1

3.3. Ternary system N N

p 1 1

The experimental VLE data of 2-propanol + 1-butanol + 1- + − + (x x ) (x + x )B + x

ic id p ic id i 2 2

− +

pentanol have been given in Table 3. The predictions of ternary (Tc C ) (T C )

i=1 i=1 i d i

system with binary interaction parameters of Wilson, NRTL and (12)

UNIQUAC equations were made. The correlation average deviations

in 2-propanol vapor-phase mole fraction were 0.0057, 0.0043, and where xic, xid, yic and yid refer to liquid-phase mole fraction and

0.0049, and in temperature were 0.52, 0.50, and 0.49, respectively vapor-phase mole fraction of adjacent point c and d respectively; Tc,

for Wilson, NRTL and UNIQUAC models. The quality of results for Td, ic and id are temperature and activity coefﬁcient of adjacent

ternary system was tested by the McDermott-Ellis method [14], points c and d; B and C are the Antoine constants; x, p and T are

which compares maximum deviation Dmax and local deference D the experiment errors of liquid-phase mole fraction, pressure and

of the adjacent point c and d. The data passed the thermodynamic temperature, respectively. In this research, x = 0.001, p = 0.065,

consistent test if it satisﬁes: T = 0.1.

| |

D < Dmax (10) 412

390 410 408 384 406 404 378 402 /K

T 400

/K 372 T 398 366 396 394 360 392

354 390

0.0 0.2 0.4 0.6 0.8 1.0

0.0 0.2 0.4 0.6 0.8 1.0

x1 , y1 x1 , y1

᭹

Fig. 3. T–x1–y1 diagram for 2-prapanol (1) + 1-butanol (2) at 101.3 kPa. , experi- Fig. 5. T–x1–y1 diagram for 1-butanol (1) + 1-pentanol (2) at 101.3 kPa. ᭹, experi-

mental data; —, Wilson regression p(x1 = 0) = 101.39 kPa, p(x1 = 1) = 101.23 kPa. mental data; —, Wilson regression p(x1 = 0) = 101.23 kPa, p(x1 = 1) = 101.20 kPa.

34 J. Wang, Z. Bao / Fluid Phase Equilibria 341 (2013) 30–34

4. Conclusions activity coefﬁcient

dipole moment

The VLE data for 2-propanol + 1-butanol, 2-propanol + 1- ϕ fugacity coefﬁcient

pentanol, 1-butanol + 1-pentanol and 2-propanol + 1-butanol + 1- ω eccentric factor

pentanol were obtained with an improved Rose still at 101.3 kPa.

We got the binary interaction parameters by regressing model Superscripts and subscripts

equations, and also made a prediction for every system, with a good cal calculated value

agreement between experiment data and correlation data. What is exp experimental value

more important is that the data both for binary and for ternary sys- sat, s saturation property

tems have passed the thermodynamic consistent test. At last, the v vapor phase property

VLE data in our experiment conditions have few reports, so this i component i

paper ﬁlled a blank in literature. j component j

List of symbols References

A12, A21 interaction parameters

A, B, C Antoine coefﬁcients [1] X.G. Zhang, China Chemical Engineering News, 5th ed., 2012.

[2] K. Mara, V.R. Bhethanabotla, S.W. Campbell, Fluid Phase Equilib. 127 (1997)

B , B , B second virial coefﬁcients

ii jj kk 147–153.

B , B , B , B cross second virial coefﬁcients

ij ji jk kj [3] N.A. Lebedinskaya, N.A. Filippov, V.I. Zayats, et al., Neftepererab. Neftekhim.

F objective function (Moscow) 2 (1974) 39.

[4] C.M. Wang, H.R. Li, L.H. Zhu, et al., Fluid Phase Equilib. 189 (2001)

N number of components 119–127.

D [5] E.F.G. Herington, J. Inst. Petrol. 37 (1951) 459–469.

P pressure [6] N.L. Cheng, Solvent Manual, Chemical Industry Press, Beijing, 2007.

[7] C.D. Zhang, H. Wan, L.J. Xue, et al., Fluid Phase Equilib. 305 (2011)

q, r structure parameters of UNIQUAC model

68–75.

R universal gas constant

[8] G.X. Zhang, L.W. Brandon, J.H. Wei, J. Chem. Eng. Data 52 (2007)

RD mean radius of gyration 878–883.

[9] N. Gultekin, J. Chem. Eng. Data 35 (1990) 132–136.

T absolute temperature

[10] J.G. Hayden, J.P. O’Connell, Ind. Eng. Chem. Process Des. Dev. 14 (1975)

Tb boiling point 209–216.

V liquid mole volume [11] P.S. Ma, Chemical Engineering Thermodynamics, Chemical Industry Press, Bei-

jing, 2005.

x liquid phase mole fraction

[12] A. Fredenslund, J. Gmehling, P. Rasmussen, Vapor–liquid Equilibria Using

y vapor phase mole fraction

UNIFAC—A Group Contribution Method, Elsevier Scientiﬁc Publishing Com-

Zc compressibility factor pany, New York, 1977.

[13] J. Gmehling, U. Onken, Vapor–liquid Equilibrium Data Collection Chemistry

Data Series, Dechema, Frankfurt, 1977.

Greek letters

[14] C. McDermott, S.R.M. Ellis, Chem. Eng. Sci. 20 (1965) 293–296.

˛ adjustable parameter of NRTL model