Document2

118 Ind. Eng. Chem. Process Des. D e V . 1082, 21, 118-127

Vapor-Liquid Equilibria by UN IFAC Group Contribution. Revision and Extension. 2

Jurgen Gmehllng'

Lehrstuhl Technische Chemie 8, University of Dortmund, 46 Lbrtmund 50, West Germany

Peter Rasmussen and Aage Fredenslund'

InsNtuffet for Kemlteknlk, The Technical University of Denmark, DK 2800 Lyngby, Denmark

The UNIFAC group-contribution method may be used for predicting activity coefficients for many nonelectrolyte liquid mixtures of interest in chemical technology. The accuracy and the range of applicability of the method are dependent on the availability of group parameters based on reliable experimental data. I n this work, some of the gaps in the group-interaction parameter table have been filled, and parameters are reported for seven new groups not previously covered by UNIFAC. I t is shown that frequently the UNIFAC equation is more flexible for correlating vapor-liquid equilibrium data than its molecular counterpart, the UNIQUAC equation.

Introduction The UNIFAC (UNIQUAC Functional Group Activity

Coefficients) group-contribution method is a reliable and fast method for predicting liquid-phase activity coefficients in nonelectrolyte, nonpolymeric mixtures at low to mod- erate pressures and temperatures between 300 and 425 K. I t has become widely used in practical chemical engineering applications, most notably in phase equilibrium calculations in cases where little or no relevant experimental information is available.

The UNIFAC method was originally developed by Fredenslund et al. (1975). Later the method was revised and its range of applicability considerably extended (Fredenslund et al., 1977a,b; Skjold-Jargensen et al., 1979). The UNIFAC method is fully described in these references, and we do not here repeat the description. It is the aim of this work to report further extensions and revisions of the UNIFAC parameter tables. New Parameters (Extension)

In this work we have extended the UNIFAC group-interaction parameter table by including experimental vapor-liquid equilibrium data published until the middle of 1980. The literature data have been collected and stored in the Dortmund Data Bank (Gmehling et al., 1977), which now contains over 10 000 vapor-liquid equilibrium data sets. Relevant, thermodynamically consistent data are automatically retrieved from the data bank and used di- rectly in the parameter estimation procedure. Most of the group-interaction parameters presented in this work are estimated in the manner described by Fredenslund et al. (1977a). Some of them are estimated using a parameter estimation program based on the principle of maximum likelihood and described by Skjold-Jargensen (1980) and by Kem6ny et al. (1981).

In the following two sections we report group-interaction parameters for new groups not previously covered by UNIFAC and parameters which fill some of the gaps in the parameter table by Skjold-Jargensen et al. (1979). New Groups

Table I presents a supplementary list of group volume and surface area parameters, Rk and Q k , for seven new groups not previously covered by UNIFAC.

Alkynes. New experimental data for alkanes with alkynes have recently been reported. This enables the

determination of a limited number of interaction parameters for mixtures containing the alkyne group.

Dimethyl sulfoxide, acrylonitrile, trichloroethylene, and dimethylformamide are included, each as one separate group. These compounds are of significant importance in chemical technology, and hence a consid- erable number of vapor-liquid equilibrium data sets for mixtures including these components have been reported (Gmehling et al., 1977). As shown in Table I, diethylformamide may be built from one dimethylformamide group (DMF-2) and two CH, groups.

Fluorinated Hydrocarbons (alkanes and aromatics) have been included. Only a small number of data sets for mixtures with fluorohydrocarbons have been published. While for chlorohydrocarbons it was possible to develop separate group-interaction parameters for the groups CC14, CC13, CCl,, and CC1, such a distinction was not possible for the groups CF,, CF2, and CF. Instead the groups CF,, CF2, and CF were defined as subgroups belonging to the same main group, "CF2". Thus their Rk and Qk values differ, but they have identical interaction parameters with any other group (e.g., uCFa,CH2 = uCF ,CH2). For subgroups belonging to the same main group, tke interaction parameters are equal to zero (e.g., uCF3,CF2 = oCF ,CF3 = 0).

The group-interaction parameters for tke new groups are given in Table 11. Filling the Gaps

Because of the increase of the number of data sets in the Dortmund Data Bank, it has been possible to determine some of the group-interaction parameters previously nonavailable because of lack of data. (These interactions are marked "ma." in Table I1 of Skjold-Jargensen et al., 1979). The results are shown in Table 111. Several of these parameters were determined on the basis of data recently measured by Smith and co-workers (see, e.g., Muthu et al., 1980). It has been found that the combinatorial part of UNIFAC alone describes the published vapor-liquid equilibrium data for the system 1,2-ethanediol-water. This means that for this system one may u ~ e UH WH = U ~ H * @ = 0. It may be pointed out that the availafie experimental data for the 1,2-ethanediol-water system are somewhat conflicting.

Parameters describing the interactions between the groups C=C/CCOO and C=C/HCOO are now available.

0196-4305/82/1121-0118$01.25/0 0 1981 American Chemical Society

Ind. Eng. Chem. Process Des. Dev., Vol. 21, No. 1, 1982 119

Table I. UNIFAC Group Volume and Surface Area Parameters for New Groups. Rk and Qk

main group sub group

“C&” C S H

“Me , SO” Me,SO ‘‘ ACRY ’’ ACRY ‘TlCC” c1-( C=C) “ACF” ACF

e=

“DMF” DMF-1 DMF-2

“CF,” CF, CF, C F

group volume group surface parameter, area parameter

Rk Q k 1.2920 1.088 1.0613 0.784 2.8266 2.472 2.3144 2.052 0.791 0.724 0.6948 0.524 3.0856 2.736 2.6322 2.120 1.406 1.380 1.0105 0.920 0.615 0.460

sample group assignment

1-hexyne: 1 CH,, 3 CH,, 1 C=CH 2-hexyne: 2 CH,, 2 CH,, 1 C=C dimethyl sulfoxide: 1 Me,SO acrylonitrile: 1 ACRY trichloroethylene: 1 CH=C, 3 C1-(C=C) hexafluorobenzene: 6 ACF dimethylformamide: 1 DMF-1 diethylformamide: 2 CH,, 1 DMF-2 perfluorohexane: 2 CF,, 4 CF,

perfluoromethylcyclohexane: 1 CF,5 CF,, 1 CF

1.00

0.80 ‘ 0.60 Y1

0.60

0.20

0 .a0

0 ,BO

t 0.60

Y1 0 ,LO

0,20

0.00

0,80

t 0.60

0.60

0.20

0 .oo

0.80

t 0.60

Yl

Yl 0.60

0.20

0.00

x1 - x1- x1- x1 - Figure 1. Experimental and predicted x-y diagrams for 16 ketone-alkane mixtures.

Thus UNIFAC may be applied to systems with, for example, vinyl acetate.

Extensions by Other Authors The matrix of UNIFAC group-interaction parameters

has recently been further extended by several authors. Hauthal et al. (1980) published more than 30 UNIFAC

parameters for systems with lactam derivatives, acetic

anhydride, multifunctional amino compounds, vinyl acetate, methylformate, and others.

Kat0 (1980) reports UNIFAC parameters for the enol ring (defined as one group) together with alcohol and alkane groups. Kat0 shows that with these new parameters, UNIFAC is capable of describing chemical and physical equilibria in mixtures containing acetylacetone, its tau- tomers, and various organic solvents.

120 Ind. Eng. Chem. Process Des. Dev., Vol. 21, No. 1, 1982

Table 11. UNIFAC GroupInteraction Parameters for Table 111. UNIFAC Group-Interaction Parameters for New Groups. amnr K Already Existing Groups, a,,,,,, K (Previously Marked

“n. a., Non-available”). main group main group m n amnr K a n m , K main group, main group,

-72.88 m n am,, K a n m , K 298.9 523.6 -184.4 c=c ccoo 71.23 269.3

CH. e= C=k CH,CO CCN CNO,

ACH ACCH, OH CH,OH

CH,CO ccoo CH,O

CH,

HZ0

cc1, (3% CCl,

CH, HZ0

CH,

CH,SH DOH

CCN

c=c ACH OH CH,OH CH,CO ccoo CH,O CCN COOH c c1 CCl, CCl,

CS, CH,

CNO,

ACH ACCH, OH CH,OH CCl, CH, c=c ACH ACCH, OH CH,OH

CH,CO CH,O ACNH,

CH,SH DOH c=c Me,SO

H,O

CCl,

CH 2

CkC c=c e= CkC Me,SO Me,SO Me , SO Me,SO Me,SO Me,SO Me, SO Me,SO Me, SO Me,SO Me , SO Me,SO Me, SO Me , SO ACRY ACRY ACRY ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ClCC ACF ACF ACF ACF ACF ACF DMF DMF DMF DMF DMF DMF DMF DMF DMF DMF DMF DMF DMF DMF DMF CF,

-246.6 -203.0

-27.70 526.5 169.9

4284. -202.1 -399.3 -139.0

-44.58 52.08

172.1 215.0 363.7 337.7

-417.2 31.66

689.0 160.8

81.57 -0.505

237.3 69.11

253.9 -21.22 -44.42 -23.30

-19.14 -90.87 -58.77 -79.54 -86.85

48.40 -47.37 125.8 389.3 101.4

145.6

44.78 -48.25 21 5.2 485.3 320.4 245.6

5629.0 -143.9 -172.4

319.0

254.8

498.6

302.2

-61.70

-293.1

78.92

-119.8 -97.71

-2.859

443.6 329.1 174.4

50.49 -2.504

-143.2 -25.87 695.0

110.4

-122.1 -215.0 -343.6

-240.0

41.57

-58.43 85.70

535.8

386.6 -165.9

-42.31 41.90 -3.167

-75.67 640.9 726.7 -8.671

-18.87 -209.3

298.4

201.7

143.2 313.8 167.9

2344.

85.32

-5.132 -237.2 -157.3

649.7 645.9

-124.6 -31.95

37.70 -133.9 -240.2

64.16 172.2

-287.1

-158.2

-186.7

-191.7

97.04

335.6

-71.00

6.699 136.6 147.3

Zarkarian et al. (1979) determined several new group- interaction parameters on the basis of infinite dilution activity coefficients obtained from gas-liquid chromatog- raphy measurements. New Interaction Parameters for the ACOH Group (Revision)

Phenol may be constructed from 5 ACH groups and 1 ACOH group, see Table IV. This means that it is necessary to establish the values for the interaction parameters

scribing interactions with the ACOH group can be determined.

UACHhcOH and UACOHACH before any other parameters de-

c=c c=c ACH ACCH, ACCH, OH CH,OH CH,OH CH,OH CH,CO CH,CO CH,CO CHO ccoo HCOO CH,O CH,O CNH, CNH, CNH ACNH, ACNH, pyridine pyridine pyridine CCN COOH CCl CNO, CNO,

OH H*O

HCOO ACCl CCl, (C),N

(C),N

ACNO , ACNO,

ACNH, ACCl ACNH, pyridine ACCl CH,O DOH

DOH Br

cc1,

(C),N cc1, ( C ) J CCN ACCl COOH ca* cc1,

CCl, ACCl

ACCl ACNO, I DOH CH,SH

468.7 959.7

-144.4 23.50

4448.0 157.1

335.5

937.9 165.1 174.5 304.1

53.90

17.12

-101.7 -287.2

-202.3 -20.11

-41.11 -99.81

-189.2 -216.8

-153.7 -351.6 -165.1

699.1

52.31 76.75

464.4 533.2 304.3

0.0 147.5a

91.65 -203.2

121.3 109.9

-127.8 561.6

-406.8 5.182

661.6 -399.1

-51.54 128.1

152.0 488.9

736.4

261.1 865.9 617.1 323.3

-313.5 587.3 309.2 356.9

1346.0

-7.838

9.207

38.99

-314.9 -85.12

64.28 0.0

461.6

a This parameter was misprinted in Skjold-JGrgensen et al. (1979).

E t h a n 0 1 -hexane

1 . 2 - D i c h l o r o e t n a n e - b e n z e n e

Figure 2. Examples of binary mixtures which are constructed from two different main groups.

In the previous UNIFAC group-interaction parameter tables, the parameters aACHhCOH and aACOH,ACH were es- tablished on the basis of vapor-liquid equilibrium data for the benzene-phenol system. Unfortunately, only one, apparently not so reliable, data set was published for this


Y1 Y1

.8 . 8

.6 . 6

. 4 . 4

.2 .2

0 0 .2 . 4 . 6 .8 x1 .2 . 4 .6 .8 x1

. 2 . 4 .6 .8 x1

Cyclohexane(1) - trichloroethylene(?) Hexane(1) - tetrachloroethylene(2) Hexane(1) - trichloroethylene(2) at 1 am at 60 OC at 60 OC

Figure 3. Experimental and predicted x-y diagrams for three chlorinated hydrocarbon-alkane systems.

Y1

.8

. 6

. 4

.2

0

X 1 . 2 . 4 .6 .8

Y 1

.8

. 6

. 4

. 2

. 2 . 4 . 6 .E x1

E t h y l b e n z ~ e (1) - nitrobenzene 12) Propylhnzereil) - nitrobenzene(2) Butylbenzene(1) - nitrobenzene(2) a t 100 OC a t 1 0 0 OC a t 100 OC

Figure 4. Experimental and predicted r-y diagrams for three alkylbenzene-nitrobenzene mixtures.

Figure 6. UNIFAC group-interaction parameters.

system. As a result, predictions for mixtures containing phenol, cresol, and other components with the ACOH group may be less reliable than is normally the case for UNIFAC predictions. For the system benzene (1) -cyclohexane (2), the selectivity of the solvent phenol (S) may be defined as the ratio of the infinite dilution activity coefficients of benzene and cyclohexane in phenol, i.e., ymp,s/yml,~ Kolbe et al. (1979) noted that while the experimental value of the selectivity for this system should

be somewhat larger than 2.1, UNIFAC with the parameter table of Skjold-Jargensen et al. (1979) yields the value 1.4.

The number of published data sets for mixtures with phenol and either toluene, xylene, or cresol is relatively large. In this work, we have simultaneously determined the parameters ~ACHACOH, a ACOH,ACH, ~ACCH~,ACOH and aACOH,ACCHa on the basis of experimental data for these systems plus new data for the system benzene-phenol measured at the University of Dortmund. As a conse-

122

Table IV. UNIFAC Group Volume and Surface-Area Parameters

Ind. Eng. Chem. Process Des. Dev., Vol. 21, No. 1, 1982

main group subgroup no. Rh Qh sample group assignment

hexane: 2 CH,. 4 CH, CH, 1 0.9011 0.848 1 “CH,”

2 “ClC”

3 “ACH”

4 “ACCH,”

5 “OH”

6 “CH,OH”

7 “H,O”

8 “ACOH”

9 “CH,CO”

1 0 T H O ”

11 “CCO 0 ”

1 2 “HCOO”

1 3 “CH,O”

1 4 “CNH,”

1 5 “CNH”

1 6 “(C),N”

1 7

18 “ACNH,”

“pyridine”

1 9 “CCN”

20 “COOH”

21 “CCl”

22 “CCl,”

“CCl,”

“CCl,”

23

24

25 “ACCl”

26 “CNO,”

27

28

29

“ACNO,”

“CS, ”

“CH,SH”

CH; CH C CH,=CH CH=CH CH,=C CH=C c=c ACH AC ACCH, ACCH, ACCH OH

CH,OH

H,O

ACOH

CH,CO

CH,CO CHO

CH,COO CH,COO HCOO

CH,O CH,O

FCH,O CH,NH, CH,NH, CHNH, CH,NH CH,NH CHNH

CH,N CH,N

ACNH,

CH-0

C A N C A N C A N CH,CN CH,CN COOH HCOOH CH,Cl CHCl CCl CH,Cl, CHC1,

CHCl, CCl,

CCl, CCl,

ACCl

CH,NO, CH,NO, CHNO, ACNO,

CS,

CH, SH CH,SH

30“ “furfural” furfural

2 0.6744 0.540 3 0.4469 0.228 4 0.2195 0.000 5 1.3454 1.176 6 1.1167 0.867 7 1.1173 0.988 8 0.8886 0.676 9 0.6605 0.485

1 0 0.5313 0.400 11 0.3652 0.120 1 2 1.2663 0.968 1 3 1.0396 0.660 1 4 0.8121 0.348 1 5 1.000 1.200

1 6 1.4311 1.432

1 7 0.92 1.40

1 8 0.8952 0.680

1 9 1.6724 1.488

20 1.4457 1.180 21 0.9980 0.948

22 1.9031 1.728 23 1.6764 1.420 24 1.2420 1.188

25 1.1450 1.088 26 0.9183 0.780 27 0.6908 0.468 28 0.9183 1.1 29 1.5959 1.544 30 1.3692 1.236 3 1 1.1417 0.924 3 2 1.4337 1.244 3 3 1.2070 0.936 34 0.9795 0.624

3 5 1.1865 0.940 36 0.9597 0.632

37 1.0600 0.816 38 2.9993 2.113 39 2.8332 1.833 40 2.667 1.553 4 1 1.8701 1.724 42 1.6434 1.416 43 1.3013 1.224 44 1.5280 1.532 45 1.4654 1.264 46 1.2380 0.952 47 1.0060 0.724 48 2.2564 1.988 49 2.0606 1.684 50 1.8016 1.448 51 2.8700 2.410 52 2.6401 2.184 53 3.3900 2.910

54 1.1562 0.844

55 2.0086 1.868 56 1.7818 1.560 57 1.5544 1.248 58 1.4199 1.104

59 2.057 1.65

6 0 1.8770 1.676 6 1 1.6510 1.368

62 3.1680 2.481

2-methylpropane: 2,2-dimethylpropane:

1-hexene: 2-hexene: 2-methyl-1 -butene : 2-methyl- 2-butene : 2,3-dimethylbutene-2: benzene : styrene: toluene: ethylbenzene: cumene : 2-propanol:

methanol :

water:

phenol :

ketone group is 2nd carbon; 2-butanone:

ketone group is any other carbon; 3:pentanone: acetaldehyde:

butyl acetate: butyl propanoate : ethyl formate:

dimethyl ether: diethyl ether diisopropyl ether: tetrahydrofuran: methylamine : propylamine : isopropylamine: dimethylamine: diethylamine: diisopropylamine :

trimethylamine: triethylamine :

aniline: pyridine : 3-methylpyridine : 2,3-dimethylpyridine : acetonitrile : propionitrile: acetic acid: formic acid: 1-chlorobutane : 2-chloropropane : 2-chloro-2-methylpropane : dichlorome thane : 1,l-dichloroethane: 2,2-dichloropropane : chloroform: l,l,l-trichloroethane: te trachloromethane:

chlorobenzene :

nitromethane: 1-nitropropane : 2-nitropropane : nitrobenzene :

carbon disulfide:

methane thiol : et haneth io1 :

furfural:

3 CH;; 1 CH’ 4 CH,, 1 C

1 CH,, 3 CH,, 1 CH,=CH 2 CH,, 2 CH,, 1 CH=CH 2 CH,, 1 CH,, 1 CH,=C 3 CH,, 1 CH=C 4 CH,, 1 C=C 6 ACH 1 CH,=CH, 5 ACH, 1 AC 5 ACH, 1 ACCH, 1 CH,, 5 ACH, 1 ACCH, 2 CH,, 5 ACH, 1 ACCH 2 CH,, 1 CH, 1 OH

1 CH,OH

1 H,O

5 ACH, 1 ACOH

1 CH,, 1 CH,, 1 CH,CO

2 CH,, 1 CH,, 1 CH,CO 1 CH,, 1 CHO

1 CH,, 3 CH,, 1 CH,COO 2 CH,, 3 CH,, 1 CH,COO 1 CH,, 1 CH,, 1 HCOO

1 CH,, 1 CH,O 2 CH,, 1 CH,, 1 CH,O 4 CH,. 1 CH. 1 CH-0 3 CH;; 1 FCH,O 1 CH,NH, 1 CHI, 1 6H,, 1 CH,NH, 2 CH,, 1 CHNH, 1 CH,. 1 CH,NH 2 CH;: 1 CH;, 1 CH,NH 4 CH,, 1 CH, 1 CHNH

2 CH,, 1 CH,N 3 CH,, 2 CH,, 1 CH,N

5 ACH, 1 ACNH, 1 C.H,N 1 CH,; 1 C5H,N 2 CH,, 1 C,H,N 1 CH,CN 1 CH;, 1 CH,CN 1 CH,, 1 COOH 1 HCOOH 1 CH,, 2 CH,, 1 CH,Cl 2 CH,, 1 CHCl 3 CH,, 1 CCl 1 CH,Cl, 1 CH,, 1 CHC1, 2 CH,, 1 CCl, 1 CHC1, 1 CH,, 1 CCl, 1 CCl,

5 ACH, 1 ACCl

1 CH,NO, 1 CH,, 1 CH,, 1 CH,NO, 2 CH,, 1 CHNO, 5 ACH, 1 ACNO,

1 cs, 1 CH,SH 1 CH,, 1 CH,SH

1 furfural


Table IV (Confinued) main group subgroup no. Rk Qk sample group assignment

3 1 “DOH”

3 2 “I”

33 “Br”

34 “ G C ”

3 5 “Me,SO”

36 “ACRY”

37 “ClCC”

38 “ACF”

39 “DMF”

40 VF,”

(CHZOH 1, I

Br CH& C=C Me,SO

ACRY

C1( C=C)

ACF

DMF-1 DMF-2

CF, CF, CF

63 2.4088 2.248

64 1.2640 0.992

65 0.9492 0.832 6 6 1.2920 1.088 67 1.0613 0.784 68 2.8266 2.472

69 2.3144 2.052

70 0.7910 0.724

7 1 0.6948 0.524

72 3.0856 2.736 73 2.6322 2.120

74 1.4060 1.380 75 1.0105 0.920 76 0.6150 0.460

Table V. UNIFAC Parameters for Interactions with the ACOH Group

1,2-ethanediol:

1-iodoethane:

1-bromoethane: 1-hexyne : 2-hex yne : dimethyl sulfoxide:

acrylonitrile:

trichloroethylene :

hexafluorobenzene :

dimethylformamide: diethylformamide :

perfluorohexane :

perfluoro methylcyclohexane :

C=C 547.4 ACH 1329.0 ACCH, 884.9 OH -259.7 CH,OH -101.7

-133.1 ccoo -36.72 pyridine -341.6

324.5 H*O CH,CO

CCl, 10000.0 DOH 838.4

1665.0

244.2 25.34

-451.6 -265.2 -601.8 -356.1 -449.4 -305.5 1827.0 -687.1

quence, it was necessary to change all subsequent interaction parameters for the group ACOH. In this connection we have used new data for phenol-alkane systems measured a t the University of Dortmund. The new group- interaction parameters for the ACOH group are given in Table V.

Predictions for mixtures with phenol, cresol, etc., should now be more reliable. For example, the predicted value of the selectivity of phenol for the benzene-cyclohexane system now becomes 2.5, which is much closer to the experimental value than previously.

The Flexibility of UNIFAC Figure 1 shows experimental and predicted x-y diagrams

for 16 different binary alkane-ketone systems. Bearing in mind that all of these diagrams are produced using the same two parameters (UCH~,CH~CO = 476.4 K; UCH C O ~ C ~ - 26.76 K), this in a qualitative way indicates the dexibifity of the UNIFAC model. A similar figure is shown by Gmehling et al. (1980) for alkane-alcohol systems, and many additional such figures are shown by Gmehling (1981).

In this section we attempt somewhat more quantitatively to assess the flexibility of the UNIFAC model. We focus the attention on binary mixtures which may be constructed from two different main groups. Examples of such mixtures are shown in Figure 2.

One may correlate a vapor-liquid equilibrium data set for, e.g., ethanol-hexane with the UNIQUAC equation and obtain two UNIQUAC parameters describing the molec-

-

1 CH,, 1 CH,, 1 I

1 CH,, 1 CH,, 1 Br 1 CH,, 3 CH,, 1 CHEC 2 CH,, 2 CH,, 1 C=C 1 Me,SO

1 ACRY

1 CH=C, 3 Cl(C=C)

6 ACF

1 DMF-1 2 CH,, 1 DMF-2

2 CF,, 4 CF,

1 CH,, 5 CH,, 1 CF

Table VI. Binary, Isothermal Vapor-Liquid Equilibrium Data Using UNIFAC and UNIQUAC

re1 sum of squares dev:

Comparison of Results from Correlating

temp, SSQ (UNIFAC)/ system K SSQ (UNIQUAC)

ethanol- 348 0.27

propanol- 363 0.85

diethylamine- 328 1.09

acetone- 328 0.89

acetone- 318 0.94

3-pentanone- 363 0.78

l-octene- 313 0.94

octane

decane

heptane

cyclohexane

decane

heptane

cyclohexane

The data were correlated using the programs based on the principle of maximum likelihood (Skjold-JQrgensen (1980)). SSQ (UNIFAC) and SSQ (UNIQUAC) are defined as

SSQ = Z[( )* + X l ( C d C ) - xl(exP)

OX

)2 + T( calc) - T( exp) 3.’1(calc) - Yl(exP)

UY )2 + ( UT

l2 1 g ( c d c ) - P(exP) OP

In both cases, the following variances were used: ux = uy = 0.005; UT = 0.1 K; u p = 1.0 mmHg.

ular interactions in the mixture. One may also correlate this data set with the UNIFAC equation and obtain two UNIFAC parameters describing the group interactions in the mixture, i.e., uCH2,0H and u O H , C H . In this way we may compare the flexibility of UNIQUAe and UNIFAC models for describing binary mixtures.

It may be shown (Maabe, 1979) that if a mixture can be described by no more than two different main groups and if the components have no main group in common, then UNIFAC reduces to UNIQUAC. This holds for the

1 CH, 2 c=c 3 ACH 4 ACCH, 5 OH 6 CH,OH 7 H,O 8 ACOH 9 CH,CO

10 CHO 11 ccoo 12 HCOO 1 3 CH,O 14 CNH, 1 5 CNH

1 7 ACNH, 18 pyridine 1 9 CCN 20 COOH 21 CCl

23 CCl, 24 CCl, 25 ACCl 26 CNO, 27 ACNO, 28 CS, 29 CH,SH 30 furfural 31 DOH 32 I 33 Br 34 c=c 35 Me,SO 36 ACRY 37 ClCC 38 ACF 39 DMF 40 CF,

1 6 (C),N

22 CCI,

0.0 2520.0 -11.12 -69.70 156.4 16.51 300.0 275.8 26.76 505.7 114.8 90.49 83.36

65.33

5339.0

24.82 315.3 91.46 34.01 36.70

-30.48

- 83.98

-101.6

-78.45 -141.3 -32.69

-52.65 -7.481 -25.31

5541.0

140.0 128.0 -31.52 -72.88 50.49

41.90 -165.9

-5.132 -31.95 147.3

-200.0 0.0 -94.78 -269.7

-52.39 8694.0

692.7 1665.0

n.a. 269.3 91.65 76.44 79.40

-82.92

-41.32 -188.0 n.a. n.a. 34.78 349.2 -24.36 -52.71 -185.1 -293.7 -203.2 -49.92 n.a. 16.62 n.a. n.a. n.a. n.a. n.a.

n.a. n.a.

n. a. 37.70 n.a.

-184.4

-3.167

61.13 340.7 0.0 -146.8 89.60 -50.00 362.3 25.34 140.1 n.a. 85.84 n.a. 52.13 -44.85 -22.31 -223.9 650.4 31.87

62.32 4.680 121.3 288.5

-22.97

-4.700 -237.7 10.38 1824.0 21.50 28.41 157.3 221.4 58.68 155.6 n.a.

n.a. -2.504

-75.67 -237.2 -133.9 n.a.

76.50 4102.0 167.0 0.0 25.82 -44.50 377.6 244.2 365.8 n.a.

n.a. 65.69 n.a. 223.0 109.9 979.8 49.80

268.2 122.9 n.a. 33.61 134.7 375.5 -97.05 -127.8 40.68 n.a. 404.3 150.6 n.a. 291.1 n.a.

n.a. n.a. -157.3

n.a.

-170.0

-138.4

-143.2

-240.2

693.9 636.1 803.2 0.0 249.1 -229.1 -451.6

-404.8 164.5

245.4 191.2 237.7 -164.0 -150.0 28.60 529.0 -132.3 185.4 -151.0 562.2 747.7 742.1 856.3 246.9 341.7 561.6 823.5 461.6 521.6 267.6 501.3 721.9 n.a.

n.a. 640.9 649.7 64.16 n.a.

-25.87

124

Table VII. UNIFAC Interaction Parameters'

Ind. Eng. Chem. Process Des. Dev., Vol. 21, No. 1, 1982

1 2 3 4 5 6 7 8 697.2 1318.0 1333.0 986.5 1509.0 637.3 603.2 -137.1 0.0 289.6 -265.2 108.7 -340.2 249.6 155.7 339.7 -481.7 -500.4 -406.8 5.182 -378.2 157.8 1020.0 529.0 669.9 649.1 860.1 661.6 252.6 n.a. 914.2 382.8 n.a. n.a. n.a. n.a. n.a. 695.0 n.a. 726.7 645.9 172.2 n.a.

634.2 903.8 5695.0 353.5 -181.0 0.0 -601.8 47 2.5 23 2.7 10000.0 n.a. -314.7 -330.4 -448.2 -598.8 -339.5 -332.9 242.8 -66.17 698.2 708.7 826.7 1201.0 920.4 417.9 360.7 1081.0 n.a. 23.48 0.0 n.a. n.a. n.a.

386.6 n.a. n.a.

n.a.

-240.0

-287.1

547.4 1329.0 884.9 -259.7 -101.7 324.5 0.0 -133.1 n.a. -36.72 n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. 10000. n.a. n.a. n.a. n.a. n.a. n.a. 838.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

-341.6

9 10 11 12 1 3 14 1 5 1 6 251.5 391.5 255.7 206.6 1 CH,

2 c=c 3 ACH 4 ACCH, 5 OH 6 CH,OH 7 H,O 8 ACOH 9 CH,CO

10 CHO 11 ccoo 1 2 moo 1 3 CH,O 14 CNH, 1 5 CNH 1 6 ( C P 17 ACNH, 18 pyridine 19 CCN 20 COOH 21 CCl 22 CCl, 23 CCl, 24 CC1, 25 ACCl 26 CNO, 27 ACNO, 28 CS, 29 CH,SH 30 furfural 31 DOH 3 2 I 33 Br 34 c=c 35 Me,SO

476.4 524.5 25.77

84.00 23.39

-52.10

-195.4 -356.1 0.0 128.0 37 2.2 n.a. 52.38 n.a. n.a. n.a. -399.1 -51.54 -287.5 -297.8 286.3 423.2 552.1 37 2.0 128.1

n.a. 303.7 160.6 317.5 n.a. 138.0

443.6 110.4

-142.6

-142.6

677.0 n.a. n.a. n.a. 441.8 306.4 -257.3 n.a. -37.36 0.0 n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

-7.838

-47.51

232.1 71.23 5.994 5688.0 101.1 -10.72 14.42 -449.4 -213.7 n.a. 0.0 -261.1 461.3 n.a. 136.0 n.a. n.a. n.a. -266.6 -256.3

-132.9 n.a.

176.5 129.5

n.a. n.a. 243.8 ma.

152.0 21.92 n.a. n.a. 41.57

- 246.3

-146.3

741.4 468.7 n.a. ma. 193.1 193.4 n.a. n.a. n.a. n.a. 372.9 0.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 312.5 n.a. n.a. 488.9 n.a. ma. n.a. n.a. n.a. 239.8 n.a. n.a. n.a. n.a. n.a. n.a.

289.3 32.14 213.1 28.06

540.5 n.a. 5.202 304.1 -235.7 n.a. 0.0 n.a. -49.30 n.a. n.a. n.a. n.a.

225.4

-180.6

-338.5

-197.7 -20.93 113.9 n.a. -94.49 n.a. 112.4 63.71 n.a. 9.207 476.6 736.4 n.a. -122.1

396.0 161.7 n.a. 83.02 359.3 48.89 ma. n.a. n.a. n.a. ma. n.a. 0.0 108.8 38.89 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 261.1 203.5 n.a. n.a. n.a. 106.7 n.a. n.a. ma. n.a. n.a. n.a.

273.6 122.8

42.70 266.0 168.0 n.a. n.a. n.a.

n.a. 141.7 63.72 0.0 865.9 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 91.13

n.a. n.a. n.a. n.a. n.a. ma. n.a. n.a. n.a. n.a.

-49.29

-73.50

-108.4

658.8 90.49 23.50

53.90 304.0 ma. n.a. n.a. n.a. n.a. n.a.

-323.0

-41.11 -189.2 0.0 n.a. n.a. n.a. n.a. n.a. -141.4 -293.7 -126.0 1088.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.


Table VI1 (Continued) 9 1 0 11 1 2 1 3 14 1 5 16

36 ACRY n.a: n.a. n.a. n.a. n.a. n.a. n.a. n.a. 37 ClCC -8.671 n.a. -18.87 n.a. -209.3 n.a. n.a. n.a. 38 ACF n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 39 DMF 97.04 n.a. n.a. n.a. -158.2 n.a. n.a. n.a. 40 CF, n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

1 7 18 1 9 20 21 22 23 24

1 CH. 287.7 597.0 663.5 35.93 53.76 24.90 104.3 2 c=k 3 ACH 4 ACCH, 5 OH 6 CH,OH 7 H,O 8 ACOH 9 CH,CO

1 0 CHO 11 ccoo 1 2 HCOO 1 3 CH,O 14 CNH, 1 5 CNH 1 6 (C13N 1 7 ACNH, 18 pyridine 19 CCN 20 COOH 21 CCI 22 CCl, 23 CC1, 24 CCI, 25 ACCl 26 CNO, 27 ACNO, 28 CS, 29 CH,SH 30 furfural 31 DOH 32 I 33 Br 34 c=c 3 5 Me,SO 36 ACRY 37 ClCC 38 ACF 39 DMF 40 CF,

1 CH,

1245.0 n.a. 668.2 764.7 -348.2 335.5 213.0 n.a. 937.3 n.a. n. a. n.a. n.a. n.a. n.a. n.a. 0.0 n. a. 617.1 n.a. n.a. n. a. n.a. 1301.0 323.3 n.a. 5250.0 n.a. n.a. n.a. 164.4 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 335.6 n.a.

n.a. -4.449 52.80 170.0 580.5 459.0

165.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.0 134.3 -313.5 n.a. 587.3 18.98 309.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

-305.5

405.9 212.5 6096.0 6.712 36.23 112.6 n.a. 481.7 n.a. 494.6 n.a. n.a. n.a. n.a. n.a. -216.8 -169.7 0.0 n.a. n.a. n.a. 74.04 492.0 356.9 n.a. n.a. 335.7 125.7 n.a. n.a. n.a. n.a. 329.1 n.a.

298.4 n.a. n.a. n.a.

-42.31

730.4 537.4 603.8 199.0 -289.5 -14.09 n.a. 669.4 n.a. 660.2

664.6 n.a. n.a. n.a. n.a. -153.7 n.a. 0.0 326.4 1821.0 1346.0 689.0 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 2344.0 n.a. n.a. n.a.

-356.3

99.61 -18.81 -114.1 75.62

325.4 n.a.

751.9 n.a. n.a. 301.1 n.a. n.a. n.a. n.a. n.a. n.a. 44.42 0.0 -84.53 -157.1

-38.32

-191.7

11.80

n.a. ma.

-314.9

-73.09 -27.94 n.a. n.a. n.a. 1169.0 n.a. n.a. n.a. 201.7 n.a. n.a. n.a.

337.1 -144.4 n.a. -112.1 -102.5 370.4 n.a. -284.0 n.a. 108.9 n.a. 137.8 n.a. n.a. -73.85 n.a. -351.6 n.a. -183.4 108.3 0.0 0.0 17.97 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a.

n.a. n.a. n.a. n.a. n.a.

-40.82

-215.0

4584.0 -231.9 -12.14 -98.12 -139.4 353.7 n.a. -354.6 n.a. -209.7 -287.2 -154.3 n.a. n.a.

n.a. -352.9

-114.7 -15.62 76.75 249.2 0.0 0.0 51.90 n.a. n.a. n.a.

n.a. 48.48 n.a. 21.76 n.a. n.a.

ma. 85.32 n.a. n.a. n.a.

-26.06

-343.6

5831.0 3.000 -141.3 143.1 -67.80 497.5 1827.0 -39.20 n.a. 54.47 n.a. 47.67

71.23

8455.0

-99.81

-8.283

-165.1 -54.86 212.7 62.42 56.33 -30.10 0.0 -255.4 -34.68

-60.71

-133.1

514.6

n.a.

n.a. 48.49 225.8 n.a.

n.a. 143.2

-58.43

-124.6 -186.7 n.a.

25 26 27 28 29 30 31 3 2

153.6 184.4 354.5 3025.0 335.8 661.5 543.0 2 c=k 3 ACH 4 ACCH, 5 OH 6 CH30H 7 H,O 8 ACOH 9 CH,CO

1 0 CHO 11 ccoo 1 2 HCOO 1 3 CH,O 1 4 CNH, 1 5 CNH 1 6 (C),N 1 7 ACNH, 18 pyridine 1 9 CCN 20 COOH 21 CCl 22 CCl, 23 CCl, 24 CC1, 25 ACCl 26 CNO, 27 ACNO, 28 CS,

321.5 959.7 538.2 -126.9 287.8 17.12 678.2 n.a. 174.5 n.a. 629.0 n.a. n.a. 68.81 4350.0

699.1 n.a. 52.31 n.a. 464.4 n.a. n.a. 475.8 0.0 794.4 n.a. n.a.

-86.36

542.1 168.0 3629.0 61.11 75.14 220.6 n.a. 137.5 n.a. n.a. n.a. 95.18 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n. a. 490.9 -154.5 0.0 -85.12 n.a.

n.a. 194.9 4448.0 157.1 n.a. 399.5 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. 534.7 n.a. 533.2 0.0 n.a.

-62.73

76.30 n.a.

-9.451 n.a. 477.0 147.5

887.1 n.a. n.a. n.a.

n.a. n.a. 183.0 n.a. n.a. 4.339 140.9 -8.538 n.a. -70.14

52.07 -10.43

-31.09 37.84

216.1 -46.28

n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 230.9 21.37 n.a. n.a. 450.1 59.02 n.a. n.a. 116.6 n.a. 132.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.0 n.a.

n.a. -64.69 -20.36 -120.5 n.a. 188.0 n.a.

n.a. 202.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

546.7 n.a. n.a. n.a. n.a.

-163.7

-64.38

n.a. n.a. 210.4 113.3 4975.0 n.a. -318.9 313.5 n.a. n.a. 0.0 n.a. -687.1 n.a. n.a. 53.59 n.a. n.a. -101.7 148.3 n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. 125.3 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 177.6 n.a. 86.40 n.a. 247.8 n.a. n.a. 139.8 304.3 n.a. n.a. n.a. n.a.

-20.11 -149.5

126 Ind. Eng. Chem. Process Des. Dev., Vol. 21, No. 1, 1982

Table VI1 (Continued)

25 26 27 28 29 30 31 32

29 CH,SH n.a. n.a. n.a. n.a. 0.0 n.a. n.a. n.a. 30 furfural n.a. n.a. n.a. ma. n.a. 0.0 n.a. n.a. 31 DOH n.a. 481.3 n.a. n.a. n.a. n.a. 0.0 n.a. 32 I n.a. 64.28 n.a. n.a. n.a. n.a. n.a. 0.0 33 Br 224.0 125.3 n.a. n.a. n.a. n.a. n.a. n.a. 34 c=c n.a. 174.4 n.a. ma. n.a. n.a. n.a. n.a. 35 Me,SO n.a. n.a. n.a. n.a. 85.70 n.a. 535.8 n.a. 36 ACRY n. a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 37 ClCC n.a. 313.8 n.a. 167.9 n.a. n.a. n.a. n.a. 38 ACF n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 39 DMF n.a. n.a. n.a. n.a. -71.00 n.a. -191.7 n.a. 40 CF, n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

33 34 35 36 37 38 39 40 689.0 -0.505 125.8 485.3 -2.859 1 CH, 479.5 298.9 526.5

2 c=k 3 ACH 4 ACCH, 5 OH 6 CH,OH 7 H,O 8 ACOH 9 CH,CO

10 CHO 11 ccoo 1 2 HCOO 13 CH,O 14 CNH, 15 CNH

17 ACNH, 18 pyridine 19 CCN 20 COOH

16 (C),N

21 CCl 22 CCl, 23 CCl; 24 CCl, 25 ACCl 26 CNO, 27 ACNO,

29 CH,SH 30 furfural 31 DOH 32 I 33 Br 34 c=c 35 Me,SO 36 ACRY 37 ClCC 38 ACF 39 DMF 40 CF,

28 cs,

n.a. -13.59 -171.3 133.4 n.a. n.a. n.a. 245.2 n.a. n.a. n. a.

n.a. n.a. n.a. n.a. n.a. n.a. n. a.

n.a. n.a. 41.94

10.17 n.a. n.a. n.a. n.a. n.a. n.a. 0.0 n.a. n.a. n.a. n.a. n.a. n. a. n.a.

-. 2 0 2.3

-125.9

-60.70

a n.a. = not available.

523.6 n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.0 n.a. n.a. n.a. n.a. 6.699 n.a.

-246.6

-203.0

-27.70

n.a. 169.9 4284.0 -202.1 -399.3 -139.0 n.a. -44.58 n.a. 52.08 n.a. 172.1 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 215.0 363.7 337.7 n.a. n.a. n.a. n.a. 31.66 n.a.

n.a. n.a. n.a. 0.0 n.a. n.a. n.a. 136.6 n.a.

-417.2

n.a. 237.3 n.a. 69.11 n.a. n.a. n.a. 253.9 n.a. -21.22 160.8 n.a. n.a. n.a.

n.a. n.a.

n.a. n.a. n.a. 145.6 ma. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

n.a. -44.42

n.a. -23.30

81.57 -19.14 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.0 n.a. n.a. n.a. n.a.

mixture 172-dichloroethane-benzene (see Figure 2). Nat- urally, in this case UNIFAC and UNIQUAC are equally flexible.

When the components have a main group in common (e.g., ethanol-hexane) the UNIQUAC and UNIFAC models differ. Two UNIFAC or two UNIQUAC parameters have been fitted to a number of binary vapor-liquid equilibrium data sets exemplified by the ethanol-benzene system. Table VI shows that as a correlating equation, UNIFAC is somewhat more flexible than UNIQUAC. This indicates that the assumptions underlying the solution of groups concept may be physically reasonable. Results

Naturally, many results could be shown using the new UNIFAC group-interaction parameters. However, only two typical examples of such predictions will be shown here.

-90.87 -58.77 n.a. -79.54 -86.85 n.a. 48.40 n.a.

n.a. n.a. n.a. ma. n.a. n.a. n.a. n.a. 0.0 n.a. n.a. n.a.

-47.31

n.a. 389.3 101.4 44.78

n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 215.2 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.0 n.a. n.a.

-48.25

320.4 245.6 5629.0 -143.9 -172.4 319.0 n.a.

n.a. n.a. n.a. 254.8 n.a. n.a. n.a.

n.a. n.a. n.a. n.a. n.a. n.a. 498.6 n.a. n.a. n.a. n.a. 78.92 n.a. 302.2 n.a. n.a. -119.8 -97.71 n.a. n.a. n.a. 0.0 n.a.

-61.70

-293.1

n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. ma. n.a. n.a. n.a. n.a. n.a. 0.0

In Figure 3, the same two group-interaction parameters (ac1.c~ = c), C H ~ and U C H ~ , c l - (c = c)) are used to calculate all three x-y diagrams.

Figure 4 shows the predicted vapor-liquid equilibria for the homologous series ethylbenzene, propylbenzene, butylbenzene with nitrobenzene.

In all of these systems the average deviation between experimental and predicted vapor phase compositions is less than 0.01 mole fraction. This is typical for cases where the group-interaction parameters are based on reliable experimental data. When the parameters are based on limited, poor data or when the molecules contain two strong functional groups close to each other, much larger average deviations may be expected.

Glycols are examples of molecules having two strong functional groups (here two OH groups) close to each other. Skjold-Jerrgensen et al. (1979) found that glycols could not

Ind. Eng. Chem. Process Des. Dev. 1982, 27, 127-134 127

be described by using two OH groups. It was necessary to introduce a special glycol group. Similar “proximity effects” are discussed by Hauthal et al. (1980).

Complete tables of Rk and Qk values and group-interaction parameters which include the extensions reported in this work are given in Tables IV and VII. As a result of the revisions and extensions of UNIFAC

described in this work, UNIFAC now encompasses 40 different main groups and 76 subgroups. Figure 5 gives an overview of the available group-interaction parameters.

The new parameter tables do not include the CCOH alcohol group introduced by Fredenslund et al. (1977). In our experience, the OH alcohol group (group no. 5 of Table VII) yields results which are as good as or better than the CCOH group. Supplement

A list of references to the data on which the new UNI- FAC parameters are based and a listing of a subroutine which incorporates the new UNIFAC parameter table in generating activity coefficients may be obtained from the authors. Acknowledgment

The authors are grateful to Deutsche Bundesminister- ium fur Forschung and Technologie and the Danish Sta- tens tekniske videnskabelige Forskningsrhd for support of

the UNIFAC project. In addition, we thank Professor U. Onken and our many other colleagues who in different ways have contributed to this work. Literature Cited Fredenslund, Aa.; Gmehllng, J.; Rasmussen, P. “Vapor-Liquid Equilibria Using

UNIFAC”; Elsevler: Amsterdam, 1977a; Chapter 5. Fredenslund, Aa.; Gmehilng. J.; Michelaen. M. L.; Rasmussen, P.; Prausnitz, J.

M. Ind. Eng. Chem. Process Des. D e v . 1977b. 16, 450. Fredenslund, Aa; Jones, R.; Prausnitz. J. M. A I C M J . 1975, 2 1 , 1086. Gmehling, J.; Onken, U.; Arlt, W. “Vapor-Liquid Equlibrlum Data Collectlon”;

DECHEMA Chemistry Data Series, Vol. 1 (12 parts): Frankfurt, 1977. Gmehling, J.; Doctorlal Thesis, (Hebllitationsschrlft), University of Dortmund.

BRD, under preparation, 1981. Gmehling, J; Rasmussen, P.; Fredenslund, Aa. Chem. Ing. Tech. 1980.

52(9), 724. Hauthai, W. H.; Schmelzer, J.; Qultzsch. K.; Mohle, L.; Figurski, G. 6th Int.

Conf . Thermodynamics Merseburg I DDR , 1980. Kato, M. Ind. Eng. Chem. Fundem. 1980. 19, 253. Kemgny, S.; SkJoidJerrgensen, S.; Manczinger, J.; T6th, K. AIChE J . 1981 In

press. Kolbe, B.; Gmehllng. J.; Onken, U. I.Chem. E . Symp. Ser. 1979, 56, 1.31

23. Maalore, B.; M. Sc. Thesis, Instltuttet for Kemlteknik, The Technlcal University

of Denmark, Lyngby, Denmark, 1979. Muhtu, 0.; Maher. P. J.; Smith, B. D. J . Chem. Eng. Data 1980, 25, 163. SkjoidJerrgensen, S.; Ph. D. Dissertatlon, Instituttet for Kemlteknik, The

Technical University of Denmark, Lyngby. Denmark, 1980. SkjoldJerrgensen, S.; Kolbe. B.; Gmehiing, J.; Rasmussen P. Ind . Eng.

Chem. Process Des. Dev. lS79, 18, 714. Zarkarlan, J. A.; Anderson, F. E.; Boyd, J. A.; Prausnltz, J. M. Ind. Eng.

Chem. Process Des. Dev. 1979, 18, 657.

Receiued for review December 4, 1980 Accepted June 30, 1981

Density, Viscosity, and Surface Tension of Coal Liquids at High Temperatures and Pressures

Shuen-Cheng Hwang and Constantine Tsonopoulos’

Exxon Research and Engineering Company, Fiorham Park, New Jersey 07932

John R. Cunnlngham

Brigham Young University, Provo, Utah 84602

Grant 1111. Wllson

Wiltec Research Company, Inc., Provo, Utah 84601

Density, viscosity, and surface tension of coal liquids have been experimentally determined at temperatures up to 850 O F and pressures up to 3200 psia. Measurements were made on liquids produced with the Exxon Donor Solvent process from Illinois and Wyoming coals. Several measurements were also made to determine the effect of dissolved hydrogen on the physical properties of coal liquids. These data were used to investigate the applicability of the existing physical property correlations to coaiderived liquids. Results indicate that the existing correlations are generally satisfactory for the temperature and pressure dependence of density but are unsatisfactory for the viscosity and surface tension of coalderlved liquids.

Introduction Coal liquefaction has drawn a lot of attention in the last

few years. Several processes are currently being investi- gated, and in every case the process development has been

hampered by the unavailability of phase-equilibrium and physical property data a t the conditions of interest. The first need has been addressed by Wilson et al. (1981). Here we are concerned only with the density, viscosity, and

0196-4305/82/1121-0127$01.25/0 0 1981 American Chemical Society

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