Three Binary Azeotropic Systems for 1-(Methoxymethoxy)-propane, 1-(Ethoxymethoxy)-propane, and Methoxy(methoxymethoxy)methane with Three Alcohols at 101.33 kPa: Experimental Data, Correlation, and Purification

Article abstract of DOI:10.1021/acs.jced.7b00740

The isobaric vapor-liquid equilibrium (VLE) data for three binary systems of 1-(methoxymethoxy)-propane and ethanol, 1-(ethoxymethoxy)-propane and 1-butanol, methoxy(methoxymethoxy)methane and 1-propanol at 101.33 kPa were measured using an improved Rose still. Three minimum boiling azeotropes were found for three binary systems containing ethanol, 1-butanol, and 1-propanol for which the azeotropic temperature and composition are 349.35 K and 70.95 mol % (ethanol), 384.02 K and 36.02 mol % (1-butanol), 368.68 K and 69.26 mol % (1-propanol), at 101.33 kPa, respectively. The VLE measurements were correlated by the Van Laar, Wilson, and nonrandom two-liquid models, and the results showed that the measurements had a good correlation by using thethree models for the three binary systems, respectively. The measurements of these three binary systems were thermodynamic as checked by the Herington semiempirical method.

Full text of DOI:10.1021/acs.jced.7b00740

Article
pubs.acs.org/jced
Cite This: J. Chem. Eng. Data 2018, 63, 138−146
Three Binary Azeotropic Systems for 1‑(Methoxymethoxy)-propane,
1‑(Ethoxymethoxy)-propane, and
Methoxy(methoxymethoxy)methane with Three Alcohols at 101.33
kPa: Experimental Data, Correlation, and Purification
Yu-He Song,† Xing-Ming Hou,‡ Juan Song,† Yue Zhang,† Jie Wang,† Ping-He Wei,† and Cun-Fu Li*,†
†Jiangsu Key Laboratory of Chiral Pharmaceuticals Biosynthesis (Taizhou University), College of Pharmacy and Chemistry &
Chemical Engineering, Taizhou University, Taizhou 225300, P. R. China
‡CNOOC Energy Technology & Services-Safety and Environmental Protection Co, Tianjin City 300450, China
ABSTRACT: The isobaric vapor−liquid equilibrium (VLE) data for three
binary systems of 1-(methoxymethoxy)-propane and ethanol, 1-(ethoxyme-
thoxy)-propane and 1-butanol, methoxy(methoxymethoxy)methane and 1-
propanol at 101.33 kPa were measured using an improved Rose still. Three
minimum boiling azeotropes were found for three binary systems containing
ethanol, 1-butanol, and 1-propanol for which the azeotropic temperature and
composition are 349.35 K and 70.95 mol % (ethanol), 384.02 K and 36.02 mol
% (1-butanol), 368.68 K and 69.26 mol % (1-propanol), at 101.33 kPa,
respectively. The VLE measurements were correlated by the Van Laar, Wilson, and nonrandom two-liquid models, and the
results showed that the measurements had a good correlation by using thethree models for the three binary systems, respectively.
The measurements of these three binary systems were thermodynamic as checked by the Herington semiempirical method.
1. INTRODUCTION
Oxygenated compounds can reduce soot formation and
increase the combustion efficiency during combustion which
Figure 1. Molecular structure of MMP.
can be used as additives of gasoline or diesel. These compounds
such as methoxy(methoxymethoxy)methane (DMM2), 1-
(methoxymethoxy)-propane (MMP), and 1-(ethoxymethoxy)-
Figure 2. Molecular structure of EMP.
propane (EMP) can be synthesized from methylal, form-
aldehyde, methanol, ethanol, and 1-propanol.1−5 However,
before their separation technology can be devoped, the vapor−
liquid equilibrium (VLE) measurements and their azeotropic
state with alcohols mixture must be determined. The VLE and
Figure 3. Molecular structure of DMM2.
azeotropic state data are always required for engineering use,
such as in the design of a distillation process. Here, we have
measured the isobaric VLE measurements at 101.33 kPa for
binary mixtures composed of three systems in this study to
provide a reference for the development of distillation
technology in the process of purifying these oxygenated
compounds.
In addition, the thermodynamics consistency of these VLE
measurements about three binary systems was checked with the
help of the traditional area test and direct test methods. These
VLE data have been compared with the result correlated by the
Van Laar,6 Wilson,7 and the NRTL8 models.
with the help of an acid catalyst under some different situations.
The DMM2 was synthesized by the mixture containing
methylal and formaldehyde under the situation of 383.15 K
and 1.0 MPa using H2SO4 as catalyst, and the yield is about
26%. The MMP was synthesized by the mixture containing
methylal and 1-propanol under the situation of 373.15 K and
0.8 MPa using AlCl3 as catalyst, and the yield is about 42%. The
main byproducts are 1-(methoxymethoxymethoxy)-propane
(MMMP) and 1-(propoxymethoxy)-propane (PMP). The
EMP was synthesized by the mixture containing ethanol, 1-
propanol, and methylal under the situation of 363.15 K and 0.6
MPa using the FeCl3 as catalyst, and the yield is about 38%.
The byproducts in the synthetic product are 1-(ethoxyme-
thoxy)-ethane (EME), 1-(ethoxymethoxymethoxy)-ethane
2. EXPERIMENTAL SECTION
2.1. Chemicals. Methanol, ethanol, 1-propanol, 1-butanol,
methylal, and formaldehyde were supplied from the Sinopharm
Chemical Reagent. The DMM2, MMP, and EMP (molecular
structure in Figures 1, 2, and 3) were synthesized by using
methanol, ethanol, 1-propanol, methylal, and formaldehyde9,10
Received: August 18, 2017
Accepted: December 4, 2017
Published: December 18, 2017
© 2017 American Chemical Society
138
DOI: 10.1021/acs.jced.7b00740
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Journal of Chemical & Engineering Data
Article
Table 1. Comparison of Density (ρ) at 293.15 K, Refractive Index (nD) at 298.15 K and the Boiling Points (Tb) at 101.33 kPa of
the Pure Components with Literature Data
a
b
b
Tb (K)
ρ (293.15 K)(kg/m3)
nD (298.15 K)
component
ethanol
this work
351.51
lit.
this work
789.2
lit.
this work
lit.
c
c
d
c
c
d
f
d
c
c
c
c
e
c
c
f
351.46
351.55
370.34
370.35
390.81
390.90
366.12
386.53
377.95
378.15
789.3
789.1
803.6
803.4
809.7
809.5
841.4
831.4
1.3595
1.3835
1.3971
1.3594
1.3593
1.3837
1.3833
1.3971
1.3974
1.3757
d
e
1-propanol
1-butanol
370.42
390.92
803.6
809.5
d
c
f
MMP
EMP
366.13
386.53
378.00
841.2
831.1
958.0
1.3757
1.3818
1.3790
g
h
i
g
ik
h
DMM2
960.0 ,
jk
959.7 ,
1.3789
a
b
Standard uncertainties u are u(T) = 0.1K, u(P) = 0.05 kPa. Standard uncertainties u are u(T) = 0.2K, u(P) = 0.3 kPa, u(ρ) = 0.2 kg/m3, u(nD) =
0.0002. Standard literature.12 Standard literature.13 Standard literature.14 Standard literature.3 Standard literature.4 Standard literature.1
c
d
e
f
g
h
i
j
k
Standard literature.15 Standard literature.16 The data of refractive index for DMM2 was the measurement at the temperature of 298.15 K.
(EMME), PMP, and a minor other compound. After that, we
carried out a complex separation and purification process in
order to obtain high purity chemicals.
First, most of the methanol or ethanol (unreacted) was
removed by flash distillation in the reaction products of MMP
and EMP. Afterward, a small quantity of formaldehyde
decomposed from methylal in the reaction product was
removed by washing using an alkaline hydrogen peroxide
solution. Following, atmospheric distillation was used to
achieve the separation of methanol, ethanol, and methylal,
and concentrates were obtained which mainly consist of MMP,
MMMP, PMP, and 1-propanol or EMP, EME, EMME, PMP,
and 1-propanol.
H2SO
Δ
4
CH3OCH2OCH3 + (CH2O)n
H3 + CH3O(CH2O)3CH3
CH3O(CH2O)2C
(1)
AlCl3
Δ
CH3OCH2OCH3 + CH3(CH2)2OH
CH3OCH2O(CH2)2CH3
Thereafter, the technology of reduced pressure distillation
was used to achieve the separation of MMP (containing the 1-
+ CH3O(CH2O)2(CH2)2CH3 + CH3(CH2)2OCH2O(CH2)2CH3
(2)
propanol of approximately 8.5 wt %) and MMMP at 101.3
1
kPa and 362.5 1 K. Similarly, the technology of reduced
FeCl3
pressure distillation was used to achieve the separation of EMP
(containing the 1-propanol of approximately 4.8 wt %) and
EME and PMP at 101.3 1 kPa and 369.5 1 K. In the course
of the experiment, we found that the boiling points of EME and
PMP are about 361 1 K and 410 1 K, respectively, and
there is no azeotropic state between EMP with EME or PMP.
Consequently, this separation process was easy to implement.
Afterward, the technology of reduced pressure distillation
was operated at 22 1 kPa and 324 1 K for MMP or at 26
CH3OCH2OCH3 + CH3CH2OH + CH3(CH2)2OH
Δ
CH3(CH2O)2(CH2)2CH3 + CH3(CH2O)2CH2CH3
+ CH3CH2O(CH2O)2(CH2)2CH3
(3)
2.2. Purification. Ethanol, 1-propanol, and 1-butanol with
purities of 99.8 wt % used in the VLE experiment were supplied
from the Sinopharm Chemical Reagent. These compounds
were further purified by a separation process of the secondary
rectification using a rectifying tower with 25 theoretical plates
and a reflux ratio at 3:1. After the separation process, the purity
of the three alcohols reached over 99.9 wt %, and the water
content was less than 0.03 wt % in the three alcohols.
There is no azeotropic state between DMM2 with methylal
or methanol as proven in our early studies, so the purification
method of DMM2 is simply direct atmospheric rectification
with the help of the rectifying tower as mentioned above under
similar operating conditions. However, there are some
azeotropic states between MMP (or EMP) with some alcohols,
therefore MMP and EMP were purified by a complicated
separation technology in which the separation process is similar
to the purification method of 1-(methoxymethoxy)-2-methyl-
propane that was described in our previous paper.11
Considering that there are two binary azeotropes between 1-
propanol with MMP or EMP, the mass content of alcohol for
the lower boiling point is higher than that of the other
compound in the synthetic materials of MMP and EMP.
Therefore, the 1-propanol was consumed during the reaction.
In the mixture after reaction, the content of 1-propanol was
very small, being about 3−8 wt %.
1 kPa and 323
conveying the boiling portion of 362.5 1 K or 369.5 1 K
which separated at 101.3 1 kPa to rectification under
1 K for EMP before removing water;
vacuum; collecting the distillate of 366.1 or 386.5 K at 101.33
kPa upon secondary rectification as the experimental chemical
of MMP and EMP. The theoretical plate number and the reflux
ratio of the rectifying tower used in the purification process
above were 25 and 3:1.
2.3. Analysis. An Agilent gas chromatograph (GC) 7890B
with a thermal conductivity detector (TCD) and a flame
ionization detector (FID, equipped with one chromatographic
column of porapak N (Hangzhou Kexiao Chemical Instrument
Company, China) and another capillary column of KB-5
(Kromat corporation, America) was used to measure the
content of these chemicals. We did not find any significant
impurities in the six chemicals after purification. The results
showed that the purities of ethanol, 1-propanol, 1-butanol,
DMM2, MMP, and EMP were ≥ 99.9 wt %. We set the
temperatures of detector, injector, and column box at 483.15 K,
473.15 K, and 373.15 to 453.15 K (programmed temperature,
heating rate of 10 K/min), respectively. The quantitative results
139
DOI: 10.1021/acs.jced.7b00740
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Journal of Chemical & Engineering Data
Article
Table 2. Materials Description
chemical name
source
ethanol
1-propanol
1-butanol
DMM2
MMP
EMP
Sinopharm,
China
Sinopharm,
China
Sinopharm,
China
Homemade
Homemade
Homemade
molecular formula
CASRN
C2H6O
64-17-5
99.8
C3H8O
71-23-8
99.8
C4H10O
71-36-3
99.8
C4H10O3
628-90-0
C5H12O2
C6H14O2
71739-38-3
139157-75-8
suppliers’ purity (wt
%)
purification method
distillation
distillation
distillation
distillation and
dehydration
distillation and
dehydration
distillation and
dehydration
final purity (wt %)
99.9
99.9
0.03
GC
99.9
0.02
GC
99.9
0.02
GC
99.9
0.02
GC
99.9
0.02
GC
water content (wt %) 0.03
analysis method GC
Table 3. Correlated Experiment Data and Deviations of Ethanol (1) + MMP (2) System by Van Laar, Wilson, and NRTL at
101.33 kPa
Van Laar
Wilson
NRTL
a
b
b
c
d
d
d
d
d
d
no.
Texp (K)
x1exp
y1exp
γ1
γ2
α12
△T
△y1
△T
△y1
△T
△y1
1
366.13
364.66
361.99
360.00
358.34
355.74
354.22
352.51
351.46
350.48
349.98
349.69
349.49
349.41
349.38
349.41
349.50
349.65
349.97
350.32
350.74
351.04
351.27
351.45
351.51
0.0000
0.0124
0.0446
0.0762
0.1099
0.1677
0.2188
0.2927
0.3592
0.4560
0.5192
0.5788
0.6336
0.6792
0.7219
0.7617
0.7993
0.8340
0.8766
0.9158
0.9504
0.9722
0.9862
0.9961
1.0000
0.0000
0.0456
0.1425
0.2203
0.2762
0.3670
0.4240
0.4857
0.5302
0.5851
0.6148
0.6442
0.6718
0.6961
0.7190
0.7441
0.7704
0.7972
0.8431
0.8778
0.9201
0.9538
0.9762
0.9933
1.0000
0.44
0.62
0.52
0.35
0.16
0.32
0.27
0.34
0.36
0.34
0.38
0.37
0.37
0.35
0.34
0.32
0.30
0.27
0.21
0.21
0.23
0.27
0.30
0.33
0.35
0.62
0.33
0.0000
0.0043
0.0128
0.0148
0.0257
0.0213
0.0213
0.0219
0.0209
0.0170
0.0165
0.0136
0.0109
0.0084
0.0077
0.0055
0.0035
0.0022
−0.0068
−0.0007
0.0004
−0.0012
−0.0008
−0.0004
0.0000
0.0257
0.0095
−0.42
−0.16
−0.07
−0.10
−0.17
0.13
0.0000
0.0027
0.0081
0.0081
0.0177
0.0125
0.0127
0.0148
0.0158
0.0153
0.0171
0.0162
0.0150
0.0136
0.0135
0.0115
0.0094
0.0077
−0.0024
0.0024
0.0021
−0.0004
−0.0005
−0.0003
0.0000
0.0177
0.0088
−0.42
−0.14
−0.03
−0.05
−0.14
0.13
0.0000
0.0022
0.0070
0.0072
0.0175
0.0134
0.0143
0.0169
0.0179
0.0168
0.0178
0.0162
0.0143
0.0124
0.0120
0.0099
0.0078
0.0063
−0.0034
0.0019
0.0021
−0.0002
−0.0003
−0.0003
0.0000
0.0179
0.0087
2
2.2317
2.1424
2.0847
1.9281
1.8539
1.7397
1.5924
1.4758
1.3341
1.2555
1.1939
1.1462
1.1116
1.0815
1.0595
1.0416
1.0268
1.0202
1.0025
0.9961
0.9974
0.9971
0.9976
1.0096
1.0164
1.0165
1.0314
1.0483
1.0678
1.1140
1.1636
1.2509
1.3365
1.4232
1.5191
1.6108
1.7201
1.8261
1.9391
2.0598
2.1214
2.3942
2.6182
2.6741
2.7474
2.7506
3.7972
3.5619
3.4235
3.0898
2.8774
2.6272
2.2821
2.0125
1.6826
1.4779
1.3175
1.1837
1.0821
0.9858
0.9098
0.8428
0.7828
0.7566
0.6600
0.6012
0.5904
0.5753
0.5755
3
4
5
6
7
0.16
0.13
8
0.28
0.23
9
0.31
0.25
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
0.26
0.20
0.29
0.23
0.26
0.21
0.23
0.19
0.20
0.16
0.17
0.14
0.13
0.11
0.09
0.07
0.04
0.03
−0.05
−0.10
−0.12
−0.10
−0.08
−0.06
−0.05
−0.42
0.16
−0.06
−0.10
−0.11
−0.09
−0.08
−0.06
−0.05
−0.42
maximum deviation
average absolute deviation
0.14
a
b
c
Standard uncertainties u are u(T) = 0.1 K, u(P) = 0.05 kPa. Expanded uncertainties U are U(x1) = U(y1) = 0.0046, P = 0.95. Relative volatility.
y
xi
d
The antoine equation used is αij = yi /x . Calculation: ΔT = (Tcal−Texp), Δy1 = (y1cal−y1exp).
j
j
were acquired by the area normalization method in the process
of analysis. The water contents were analyzed by the GC7890B
with porapak N and TCD for which the detection limit for
water content in an organic compound is 0.001 wt %. The
water content was ≤ 0.03 wt % in ethanol and 1-propanol and
≤ 0.02 wt % in 1-butanol, MMP, EMP, DMM2. The sources,
purity, and water content of the reagents are listed in Table 1.
As additional purity checks, we tested the normal boiling
points, densities (ρ), and refractive indices (nD) of six pure
chemicals and compared these measurements with the
literature values12−16 presented in Table 2. The methods of
measurement and calculation for three physical property
parameters have been described in our previous paper.4
The normal boiling point of each pure chemical at 101.33
kPa was measured by a modified Rose still whose uncertainty is
0.05 K and 0.02 kPa. The density of each pure chemical was
measured at 293.15
0.1 K and 101.33
0.25 kPa by the
pycnometer (Tianjin Glass Company LTD, Tianjin, China)
method for which the uncertainty of its capacity was 0.03%.
The pycnometer was verified by calculating on the basis of
weight the filling quality when absolutely packed with the
distilled water at 25 °C. The electronic analytical balance
(Mettler Toledo Instrument Company, Switzerland) for which
the accuracy is 0.0001 was used to weigh the relative quality.
The refractive index of each pure chemical was measured at
298.15
0.1 K and 101.33
0.15 kPa by an Abbe
refractometer (Shanghai INESA Instrument Company, China).
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Table 4. Experiment Data and Deviations Correlated of 1-Butanol(1) + EMP (2) System by Van Laar, Wilson and NRTL at
101.33 kPa
Van Laar
Wilson
NRTL
a
b
b
c
d
d
d
d
d
d
no.
Texp (K)
x1exp
y1exp
γ1
γ2
α12
△T
△y1
△T
△y1
△T
△y1
1
386.53
386.13
385.78
385.21
384.61
384.27
384.13
384.05
384.11
384.26
384.48
384.82
385.31
385.82
386.57
387.20
387.88
388.52
389.20
389.60
389.98
390.72
390.92
0.0000
0.0245
0.0516
0.0972
0.1692
0.2289
0.2830
0.3342
0.3930
0.4517
0.5042
0.5662
0.6343
0.7006
0.7624
0.8083
0.8533
0.8891
0.9270
0.9483
0.9664
0.9936
1.0000
0.0000
0.0325
0.0643
0.1212
0.1962
0.2534
0.2983
0.3395
0.3840
0.4274
0.4672
0.5130
0.5688
0.6237
0.6824
0.7320
0.7807
0.8261
0.8774
0.9107
0.9392
0.9877
1.0000
1.12
1.03
0.93
0.89
0.80
0.78
0.72
0.71
0.64
0.57
0.50
0.44
0.37
0.40
0.32
0.30
0.32
0.33
0.42
0.51
0.57
0.58
0.56
1.12
0.60
0.0000
−0.07
−0.03
−0.01
0.11
0.0000
−0.07
−0.02
0.00
0.0000
2
1.5713
1.4995
1.5312
1.4561
1.4082
1.3481
1.3030
1.2502
1.2040
1.1693
1.1291
1.0974
1.0689
1.0456
1.0335
1.0188
1.0108
1.0044
1.0048
1.0028
0.9991
1.0006
1.0053
1.0085
1.0200
1.0311
1.0464
1.0633
1.0858
1.1124
1.1372
1.1763
1.2181
1.2791
1.3318
1.3678
1.4342
1.4776
1.5523
1.5781
1.6344
1.7012
1.3345
1.2640
1.2808
1.1983
1.1433
1.0772
1.0240
0.9626
0.9060
0.8623
0.8072
0.7605
0.7085
0.6695
0.6476
0.6121
0.5924
0.5634
0.5561
0.5375
0.5174
0.0047
0.0013
0.0013
3
0.0104
0.0041
0.0040
4
0.0099
0.0005
0.11
0.0004
5
0.0108
0.21
−0.0009
−0.0040
−0.0037
−0.0045
−0.0044
−0.0045
−0.0056
−0.0049
−0.0072
−0.0060
−0.0068
−0.0087
−0.0056
−0.0051
−0.0024
−0.0024
−0.0007
0.0000
0.21
−0.0008
−0.0038
−0.0034
−0.0042
−0.0042
−0.0043
−0.0055
−0.0050
−0.0074
−0.0063
−0.0071
−0.0089
−0.0057
−0.0051
−0.0023
−0.0024
−0.0007
0.0000
6
0.0078
0.30
0.30
7
0.0072
0.31
0.31
8
0.0052
0.35
0.35
9
0.0034
0.33
0.33
10
11
12
13
14
15
16
17
18
19
20
21
22
23
0.0012
0.30
0.29
−0.0019
−0.0035
−0.0082
−0.0090
−0.0111
−0.0135
−0.0104
−0.0095
−0.0058
−0.0051
−0.0027
−0.0004
0.0000
0.25
0.25
0.21
0.20
0.15
0.14
0.17
0.16
0.07
0.06
0.01
0.01
−0.01
−0.05
−0.01
0.04
−0.01
−0.05
−0.01
0.04
0.07
0.07
0.01
0.01
−0.02
0.35
0.0000
−0.02
0.35
0.0000
maximum deviation
average absolute deviation
−0.0135
0.0062
−0.0087
0.0036
−0.0089
0.0036
0.13
0.13
a
b
c
Standard uncertainties u are u(T) = 0.1 K, u(P) = 0.05 kPa. Expanded uncertainties U are U(x1) = U(y1) = 0.0030, P = 0.95. Relative volatility.
y
xi
d
The antoine equation used is αij = yi /x . ΔT = (Tcal − Texp), Δy1 = (y1cal − y1exp
)
j
j
Table 5. Experiment Data and Deviations Correlated of 1-Propanol (1) + DMM2 (2) System by Van Laar, Wilson, and NRTL at
101.33 kPa
Van Laar
Wilson
NRTL
a
b
b
c
d
d
d
d
d
d
no
Texp (K)
x1exp
y1exp
γ1
γ2
α12
△T
△y1
△T
△y1
△T
△y1
1
378.00
376.67
374.85
373.16
372.02
371.17
370.30
369.72
369.26
369.03
368.84
368.71
368.70
368.74
368.85
369.05
369.40
369.78
370.26
370.42
0.0000
0.0154
0.0791
0.1488
0.2209
0.2771
0.3515
0.4157
0.4851
0.5354
0.5901
0.6557
0.7107
0.7634
0.8052
0.8513
0.9053
0.9469
0.9900
1.0000
0.0000
0.0305
0.1390
0.2349
0.3178
0.3749
0.4428
0.4944
0.5467
0.5828
0.6212
0.6675
0.7073
0.7474
0.7812
0.8224
0.8760
0.9258
0.9850
1.0000
0.50
1.11
0.74
0.59
0.31
0.29
0.26
0.25
0.24
0.22
0.22
0.23
0.22
0.24
0.25
0.26
0.28
0.32
0.41
0.41
1.11
0.37
0.0000
0.0027
0.0118
0.0168
0.0179
0.0165
0.0128
0.0105
0.0073
0.0051
0.0028
0.0004
−0.0013
−0.0023
−0.0026
−0.0029
−0.0017
−0.0019
−0.0006
0.0000
0.0179
0.0059
−0.47
0.23
0.0000
0.0007
0.0044
0.0073
0.0086
0.0082
0.0066
0.0064
0.0055
0.0051
0.0045
0.0037
0.0031
0.0026
0.0025
0.0018
0.0020
0.0005
−0.0001
0.0000
0.0086
0.0037
−0.47
0.24
0.0000
0.0006
0.0042
0.0073
0.0090
0.0088
0.0073
0.0071
0.0060
0.0053
0.0045
0.0035
0.0027
0.0021
0.0020
0.0015
0.0019
0.0005
−0.0001
0.0000
0.0090
0.0037
2
1.5779
1.4914
1.4258
1.3560
1.3165
1.2664
1.2221
1.1785
1.1483
1.1189
1.0875
1.0634
1.0443
1.0308
1.0183
1.0065
1.0025
1.0019
1.0175
1.0191
1.0299
1.0380
1.0518
1.0729
1.0998
1.1346
1.1657
1.2066
1.2661
1.3264
1.3981
1.4664
1.5495
1.6802
1.7751
1.8843
2.0175
1.8790
1.7560
1.6433
1.5644
1.4660
1.3741
1.2800
1.2119
1.1393
1.0541
0.9839
0.9170
0.8637
0.8087
0.7390
0.6987
0.6601
3
0.13
0.15
4
0.17
0.18
5
0.01
0.02
6
0.05
0.05
7
0.06
0.06
8
0.08
0.07
9
0.07
0.06
10
11
12
13
14
15
16
17
18
19
20
0.05
0.04
0.05
0.03
0.04
0.02
0.00
0.00
0.00
0.00
−0.01
−0.04
−0.07
−0.08
−0.05
−0.07
−0.47
0.09
−0.01
−0.04
−0.06
−0.07
−0.05
−0.07
−0.47
0.09
maximum deviation
average absolute deviation
a
b
c
Standard uncertainties u are u(T) = 0.1 K, u(P) = 0.05 kPa. Expanded uncertainties U are U(x1) = U(y1) = 0.0028, P = 0.95. Relative volatility.
y
xi
d
The antoine equation used is αij = yi /x . ΔT = (Tcal − Texp), Δy1 = (y1cal − y1exp).
j
j
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a
Table 6. Parameters in the Extended Antoine Equation
component
A
B
C
E
F
G
T range (K)
b
ethanol
67.56720
88.13400
22.10877
74.72410
18.77778
20.92615
−7164.30000
−8498.60000
−3137.02000
−7223.44000
−1773.91012
−7.32700
0.00000
0.000
−9.077
0.000
0.000
0.000
0.000
3.1340 × 10−06
8.3303 × 10−18
0.0000
2
6
0
0
0
0
273.0−405.0
273.0−423.0
288.0−404.0
295.0−395.0
290.0−380.0
314.0−394.0
b
1-propanol
c
1-butanol
−94.43000
−8.25216
−121.50099
d
DMM2
0.0000
e
MMP
0.0000
f
EMP
−3068.23568
−60.03471
0.0000
The extended antoine equation used is eq 14. Standard literature.12 Standard literature.17 Standard literature.16 The antoine equation used is
a
b
c
d
B
T(K)
ln ps(mmHg) = A +
+ C ln T(K)
i
e
f
Standard literature.3 Standard literature.4
These results showed that these measurements were basically
experimental data for chromatographic analysis includes five
aforementioned elements which can be described by eq 4.
consistent with literature data. We analyzed the compositions
of vapor and liquid samples at the equilibrium state by the same
GC and operating condition above.
2
U = Kc (ur(sample))2 + (ur(true))2 + (ur(cal))2 + (ur(rep))2 + (ur(LOD)
)
(4)
2.4. Apparatus and Procedure. Similar to our previous
work, the VLE data of three binary mixtures above at 101.33
kPa were measured by a dynamic modified Rose still1 which is a
typical experiment apparatus: its total capacity is 150 mL, and
the reflux rate of the condensate is about 10−15 mL/min. A
detailed description about the operation and veracity of the
apparatus in measuring the VLE value has been reported.4,11
First, compound no. 1 was injected into the kettle, and the
content of another compound in the kettle was increased from
0% to 100% at intervals. There are 20−25 sets of samples
measured for which the concentrations are different in one
binary system experiment. In the experiment, we measured the
temperature by using a precise standard mercury thermometer
(Beijing Glass Research Institute Co., second-class) with an
error range of less than 0.1 K. Meanwhile, the experimental
apparatus must remain sealed under the pressure demand
which was kept at 101.33 0.03 kPa by the pressure control
system in the measuring process. We usually measure the
pressure of the apparatus by a digital display vacuum measuring
instrument (Taizhou Aide Mechanical and Electrical Technol-
ogy Co., VR-208C-510A) with an error range of less than 0.02
kPa, which was controlled and adjusted by two buffer bottles
(the volume is 5 L) and a sealed rubber tube (its length and
inner diameter are 1 m and 0.8 cm, respectively) with a moving
clip.
where in this equation, ur(sample) means for the relative standard
uncertainty of sediment sample mass determination, ur(true)
represents the relative standard uncertainty of recovery
determination, ur(cal) stands the relative standard uncertainty
of calibration step, ur(rep) stands the relative standard
uncertainty of repeatability, ur(LOD) stands the relative standard
uncertainty of LOD determination. These relative standard
uncertainties can be calculated by eqs 5, 6, 7, and 8:
RSDR
ur(true)
ur(cal)
ur(rep)
ur(LOD)
=
(5)
(6)
(7)
(8)
n
RSDf
=
n
RSD
x
=
n
LOD
cm
=
RSD is the relative standard deviation calculated by using the
following eq 9:
∑n (xi − x)
SD
̅
i
RSD =
=
(n − 1)x2
In the process of experiment, sufficient equilibrium could be
established by continuously circulating the liquid and vapor
phase when the temperature remained constant for 60 min.
Two condensed samples of vapor and liquid (the volume is 2
mL, respectively) were withdrawn rapidly and simultaneously
when sufficient equilibrium was set up to analyze their content.
x
(9)
̅
̅
The expanded uncertainty of the VLE measurement of three
binary systems, MMP + ethanol, EMP + 1-butanol, and DMM2
+ 1-propanol, were calculated by these equations, using a
coverage factor of 2 (for P = 95%). The highest values of the U
of the three binary systems were 0.0046, 0.0030, and 0.0028,
respectively.
3.3. Thermodynamic Consistency. The thermodynamic
consistency of the VLE experimental data for the three binary
systems was checked by the traditional area test and the direct
test methods. Under normal conditions the value of D−J must
be less than 10; D and J are calculated by eqs 10 and 11:19,20
3. RESULTS AND DISCUSSION
3.1. Experimental Results. The isobaric VLE experiment
data, activity coefficients, relative volatility, and their deviations
comparing measurements with calculation values which were
correlated by using Van Laar, Wilson, and NRTL models for
three binary mixtures composed of MMP + ethanol, EMP + 1-
butanol, and DMM2 + 1-propanol at 101.33 kPa are listed in
Tables 3, 4, and 5.
3.2. Expanded Uncertainty. The calculation method of
the uncertainty is similar to the methods which are described in
a previous reference.11−18 The expanded uncertainty (U) of
|I|
D =
× 100
∑
(10)
(11)
θ
Tmin
J = 150 ×
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I = ∫ 10 ln(γ1/γ2) dx1, ∑ = ∫ 10|ln(γ1/γ2)| dx1, θ = Tmax − Tmin
.
The Tmin and Tmax are the lowest and the highest boiling point
(K) in three binary systems VLE data, respectively.
The equilibrium relationship about the VLE system is
expressed by eq 12:
l
s
i
⎛
⎞
Vi (p − p )
V
s
s
⎜
⎜
⎝
⎟
⎟
⎠
yφ P = xiγφ p exp
i
i i
i
i
RT
(12)
where, in this equation, φVi means for the fugacity coefficient of
component i in the vapor mixture. φsi stands for the fugacity
coefficient of pure vapor i at the state of equilibrium. P and T
are the system total pressure and equilibrium temperature.
Considering the experimental operation at low pressure
(101.33 kPa), and assuming the vapor phase as an ideal gas,
we neglect the pressure effect of the liquid phase fugacity in eq
13.
yp = xiγps
(13)
i
i
where psi stands for the saturated vapor pressure of pure
component i under the corresponding equilibrium temperature,
which is calculated by the extended Antoine eq 14. The
parameters of the six studied chemicals are listed in Table 6.
Figure 4. Diagram of ln(γ1/γ2) to x1 for the ethanol(1) and MMP(2)
system.
B
ln ps(Pa) = A +
+ DT(K)
i
T(K) + C
+ E ln T(K) + FT(K)G
(14)
The results of thermodynamic consistency for three binary
systems measurements are illustrated in Table 7 and Figures 4,
5, and 6, which indicate that they have passed the consistency
test of thermodynamics.
Table 7. Thermodynamic Consistency Test of VLE Data
Tmax
(K)
Tmin
(K)
system
D
J
D − J
ethanol (1) + MMP
1-butanol(1) + EMP
366.13
390.92
349.35
380.02
368.68
11.280
7.109
8.451
7.205
2.695
3.792
4.075
4.414
4.659
1-propanol (1) + DMM2 378.00
The relative volatilities between MMP, EMP, and DMM2
with the relevant alcohol are illustrated in Tables 3, 4, and 5
which are calculated by the eq 15:
y
xi
xj
i
αij =
/
Figure 5. Diagram of ln(γ1/γ2) to x1 for the 1-butanol(1) and EMP(2)
system.
y
j
(15)
The evolution of relative volatility for three binary systems
indicated that it is difficult to separate two compounds in binary
system mixtures by ordinary distillation.
The average absolute deviations for the equilibrium temper-
ature and vapor phase mole fraction of three VLE systems
above were also listed in Table 8. These binary energy
interaction parameters can be obtained by these following
equations:
3.4. Correlations for Binary VLE. In this work, the
experimental isobaric VLE data for three binary mixtures
composed of MMP + ethanol, EMP + 1-butanol, and DMM2 +
1-propanol at 101.33 kPa were correlated by the van Laar,
Wilson, and NRTL models. The binary interaction parameters
of all models were estimated using the minimization of the
following objective function, OF. The results are shown in
Table 8.
Van Laar:
Λij = (λij − λii)/RT
(17)
|Ai|xi
zi =
|Ai|xi + |B |(1 − xi)
(18)
n
2
⎛
⎝
⎞
⎠
i
2
⎜
⎟
⎟
OF =
(y
− y
)2 + (T − T
i,k,exp
)
k,exp
∑ ∑
k,cal
⎜
i,k,cal
A =
x Λ /(1 − x )
∑
i
j
ij
i
k=1 i=1
j
(19)
(16)
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Wilson:
⎛
⎞
n
n
⎛
⎞
Λkixk
⎜
⎜
⎝
⎟
⎟
⎠
⎜
⎜
⎝
⎟
⎟
⎠
ln γ = 1 − ln
Λ x
−
∑
∑
ij
j
n
i
∑
Λkjxj
j=1
j=1
k=1
(24)
NRTL:
n
n
n
⎛
⎝
⎞
∑
i=1 τjiGjixj
Gjixj
∑
i=1 τjiGjixj
⎜
⎜
⎟
⎟
ln γ =
+
τ −
∑
n
c
ij
n
i
∑
k=1 Gkixk
∑
Gkixk
∑
Gkixk
⎠
k=1
k=1
i=1
(25)
These binary interaction energy parameters obtained can be
used to predict these equilibrium temperature and vapor phase
composition of a binary system. The t−x−y diagrams about
binary mixtures composed of MMP + ethanol, EMP + 1-
butanol, and DMM2 + 1-propanol at 101.33 kPa are depicted in
Figures 7, 8, and 9 correlated by Van Laar, Wilson, and the
Figure 6. Diagram of ln(γ1/γ2) to x1 for the 1-propanol(1) and
DMM2(2) system.
B =
x Λ /(1 − x )
∑
i
j
ji
i
j
(20)
(21)
(22)
Wilson:
Λij = exp[−(λij − λii)/RT]
NRTL:
τ = (λij − λii)/RT, Gij = exp(−αijτij)
ij
The γi can be calculated as follows:
Van Laaar:
Figure 7. T−x−y diagram for the ethanol (1) and MMP (2) system at
101.33 kPa.
⎢
⎥
⎥
⎛
⎜
⎝
⎞
⎟
⎠
AiB
2
i
⎢
ln γ = A (1 − z ) 1 + 2z
− 1
i
i
i
i
⎢
⎣
⎥
⎦
|A B |
i
i
(23)
Table 8. Van Laar, Wilson, and NRTL Equation Parameters and Mean Absolute Deviations of the Binary Systems
model parameters
(λ21 − λ22)/J·mol−1
average absolute deviation
a
b
c
model
(λ12 − λ11)/J·mol−1
αij
|ΔT|
|Δy1|
Ethanol (1) + MMP (2)
3192.3886
Van Laar
Wilson
NRTL
2780.8918
−1119.7136
2447.4308
0
0
0.33
0.16
0.14
0.0095
0.0088
0.0087
−2218.1119
726.0123
0.3
1-Butanol (1) + EMP (2)
1944.2227
Van Laar
Wilson
NRTL
1914.6532
−734.2971
1181.1145
0
0.60
0.13
0.13
0.0062
0.0036
0.0036
−1094.1274
597.2182
0
0.3
1-Propanol (1) + DMM2 (2)
2162.7502
Van Laar
Wilson
NRTL
1674.2004
−6.0401
2582.2216
0
0.37
0.09
0.09
0.0059
0.0037
0.0037
−2024.5142
−537.0202
0
0.3
a
b
c
Parameter of NRTL is set to 0.3 when the mixture contains a polar component. |ΔT| = ∑ |Tcal−Texp|/k. |Δy1| = ∑ |ycal−yexp|/k. k is the number of
data points.
144
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50 mol % (MMP) + 50 mol % (ethanol), 50 mol % (EMP) +
50 mol % (1-butanol), and 50 mol % (DMM2) + 50 mol % (1-
propanol) in the kettle. The azeotropic data for these systems
are 349.52 K and 70.84 mol % (ethanol), 384.20 K and 36.10
mol % (1-butanol), and 368.79 K and 69.16 mol % (1-
propanol) measured by the rectifying process.
4. CONCLUSIONS
In this work, the VLE data for three binary mixtures composed
of MMP + ethanol, EMP + 1-butanol, and DMM2 + 1-propanol
at 101.33 kPa were measured by using a dynamic modified
Rose still. The t−x−y diagram of three binary systems at 101.33
kPa shows three minimum boiling azeotropes. The azeotropic
states are 349.35 K and 70.95 mol %(ethanol) for MMP +
ethanol mixture, 384.02 K and 36.02 mol %(1-butanol) for
EMP + 1-butanol mixture, and 368.68 K and 69.26 mol %(1-
propanol) for DMM2 + 1-propanol mixture, respectively. Our
VLE measurements passed the thermodynamic consistency test
with the help of the Herington semiempirical method. They
were correlated by using the Van Laar, Wilson, and NRTL
models for which the binary interaction energy parameters were
obtained, and there is a good correlation for the three models.
The average absolute deviations (ΔT/Δy) correlated under the
Wilson and NRTL models were less than 0.16 K and 0.0088,
respectively. Therefore, there is reason to believe that the
measurements can be applied to design separation technologies
during purifying the MMP, EMP, and DMM2.
Figure 8. T−x−y diagram for the 1-butanol (1) and EMP (2) system
at 101.33 kPa.
AUTHOR INFORMATION
Corresponding Author
*Tel.: +86 133 6522 3311. E-mail licunfu2017@163.com.
■
ORCID
Yu-He Song: 0000-0002-2366-5481
Cun-Fu Li: 0000-0002-3404-4891
Funding
The authors thank the Taizhou University research project
(No. TZXY2015QDXM025) and the Project of Natural
Science Research of Higher Education Institutions of Jiangsu
Province (No. 15KJD530001) for financial support for this
work.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
Figure 9. T−x−y diagram for the 1-propanol (1) and DMM2 (2)
system at 101.33 kPa.
We wish to thank Prof. Joshua Qingsong Li at China University
of Petroleum-East China for his support with valuable
calculations.
NRTL three models. By comparing, it is very significant that
these calculated values can be correlated with a good degree of
accuracy with these experimental data.
ABBREVIATIONS AND SYMBOL LIST
A, B, C, D, E, F, G = parameters of the extended Antoine
equation
zi, Ai ,Bi ,Λij and Λji = binary energy interaction parameters of
van Laar model
Λij and Λji = binary energy interaction parameters of Wlsion
model
■
3.5. Calculation and Determination for Azeotropic
Data. The azeotropic data of three binary systems for MMP +
ethanol, EMP + 1-butanol, and DMM2 + 1-propanol were
estimated based on the T−x−y diagram which was described by
using these calculated data correlated by the NRTL model. The
confirmed azeotropic states are 349.35 K and 70.95 mol %
(ethanol), 384.02 K and 36.02 mol % (1-butanol), and 368.68
K and 69.26 mol % (1-propanol) for the three binary systems.
In addition, we measured the azeotropic data of the three
binary systems by a rectifying process using a rectifying column
whose theoretical plate number is 25 under the condition of
total reflux. The composition of the binary system mixtures are
Gij, and τij = binary energy interaction parameters of NRTL
model
T = absolute temperature
Tb = boiling temperature
Vil = the molar volume of pure liquid
P = pressure
ps = saturated pressure
145
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Journal of Chemical & Engineering Data
Article
(16) Boyd, R. H. Some Physical Properties of Polyoxymethylene
Dimethyl Ethers. J. Polym. Sci. 1961, 153, 133−141.
(17) Walas, S. M. Phase Equilibria Chemical Engineering, 1st ed.; EUA:
Butterworth: Boston, 1985.
aij and bij = binary interaction parameters
x = mole fraction in liquid
y = mole fraction in vapor
nD = refractive index
c = average concentration of the analyte
́
(18) Konieczka, P.; Namiesnik, J. Estimating Uncertainty in
Analytical Procedures Based on Chromatographic Techniques. J.
Chromatogr. A 2010, 1217, 882−891.
GREEK LETTERS
(19) Ma, P. S. Chemical Engineering Thermodynamics; Chemical
Industry Press: Beijing, 2009.
■
α = NRTL nonrandomness parameter
γ = activity coefficient
ρ = density
(20) Wisniak, J.; Apelblat, A.; Segura, H. An Assessment of
Thermodynamic Consistency Tests for Vapor-Liquid Equilibrium
Data. Phys. Chem. Liq. 1997, 35, 1−58.
Δ = standard deviation
SUBSCRIPTS
■
cal = calculated value
exp = experimental value
i, j = component
k and n = data number
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DOI: 10.1021/acs.jced.7b00740
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