Solubilities of N -[(4-bromo-3,5-difluorine)-phenyl]maleimide in pyridine, acetone, tetrahydrofuran, ethanol, trichloromethane, and acetonitrile at temperature between (285.00 and 350.15) K

Article abstract of DOI:10.1021/je100819f

The solubility of N-[(4-bromo-3,5-difluorine)-phenyl]maleimide in pure pyridine, acetone, tetrahydrofuran, ethanol, trichloromethane, and acetonitrile at temperature between (285.00 and 350.15) K under atmospheric pressure was investigated. A laser monito

Full text of DOI:10.1021/je100819f

158
J. Chem. Eng. Data 2011, 56, 158–160
Solubilities of N-[(4-Bromo-3,5-difluorine)-phenyl]maleimide in Pyridine, Acetone,
Tetrahydrofuran, Ethanol, Trichloromethane, and Acetonitrile at Temperature
between (285.00 and 350.15) K
Yanxun Li, Li Xu, Xinding Yao, Tingliang Luo, and Guoji Liu*
College of Chemical and Energy Engineering, Zhengzhou University, Zhengzhou 450001, P.R. China
The solubility of N-[(4-bromo-3,5-difluorine)-phenyl]maleimide in pure pyridine, acetone, tetrahydrofuran,
ethanol, trichloromethane, and acetonitrile at temperature between (285.00 and 350.15) K under atmospheric
pressure was investigated. A laser monitoring observation technique was used to determine the dissolution
of the solid phase in solid + liquid mixture. The experimental solubility data were correlated with the
modified Apelblat equation.
added to the reaction flask, and the mixture was maintained for
hours at the temperature of 383.15 K until no water drops
appeared in the water separator. Toluene was removed by
distillation and then cooled to room temperature, and BDPM
[11.12 g, mp (470.45 to 470.85) K, 1HNMR (CDCl3, 400 MHz,
δ): 7.13-7.18 (m, 2H, CH), 7.35-7.42 (m, 2H, ArH)] was
obtained by filtering, washing, and drying.
Introduction
Halogen-substituted N-phenylmaleimide (XPM) monomers
due to the rigid imide rings in the backbones are usually
designed to modify thermal stability and fire resistance of
organic matrix materials.1-5 N-[(4-Bromo-3,5-difluorine)phe-
nyl]maleimide (BDPM, Figure 1) is a new XPM monomer with
fluorine and bromine atoms for polyreaction. BDPM was
synthesized by the interaction of 4-Bromo-3,5-difluoroaniline
with maleic anhydride. Crude BDPM was gained after concen-
trating and filtrating. For extensive halogen-substituted N-
phenylmaleimide polymers investigation, crude BDPM has to
be purified by crystallization. To improve the purity and yield
of BDPM, we require the solubility data of BDPM in different
solvents.
In this article, solubility measurement of BDPM in pure
pyridine, acetone, tetrahydrofuran, ethanol, trichloromethane,
and acetonitrile at temperature between (285.00 and 350.15) K
was performed at atmospheric pressure by a laser monitoring
observation technique. Experimental data were correlated by
the modified Apelblat equation.6
The solubility of BDPM in six pure solvents was measured
by the similar method that was described in the literature.7-9
The experiments were carried out in a 50 mL jacketed glass
vessel with a magnetic stirrer. The temperature, with an
uncertainty of ( 0.05 K, was controlled by circulating water
through the outer jacket. To prevent the evaporation of the
solvent, we introduced a condenser vessel. A laser monitoring
system that consisted of a laser generator, a photoelectric
transformer, and a light intensity display was used to determine
the disappearance of the last crystal in the mixtures. An
electronic balance (Shimadzu AX200) with uncertainty of (
0.0001 g was used for the mass measurements.
During the measurement, predetermined excess amounts of
solute and solvent of known masses were added to the jacket
vessel. The contents of the vessel was stirred continuously for
30 min at a fixed temperature. Then, additional solvent of known
mass was introduced to the cell. When the last solute just
disappeared, the laser intensity penetrating through the vessel
reached maximum, and the solvent mass consumed in the
measure was recorded. Together with the mass of solute, the
solubility would be obtained. The saturated mole fraction
solubility of BDPM can be determined from eq 1
Experimental Section
Materials. The N-[(4-bromo-3,5-difluorine)-phenyl]maleimide
was produced by ourselves. Its mass fraction purity was > 99.3
%, determined by HPLC [column: ZORBAX SA C18 (5 µm,
200 nm × 4.6 mm) using the methanol as the mobile phase].
The melting point is (470.6 ( 0.3) K (measured by DSC). All
of the solvents, pyridine, acetone, tetrahydrofuran, ethanol,
trichloromethane, and acetonitrile (purchased from the Tianjin
Kewei of China) used for experiments were analytical reagent
grade, and their mass fraction purities were higher than 99.8
%. Distilled deionized water of HPLC grade was used throughout.
Apparatus and Procedure. The BDPM was produced by the
following method: 80 mL of toluene, 15 mL of DMF, and 4.54 g
maleic anhydride were put in a 250 mL four-mouth flask,
respectively; then, 8.00 g 4-bromo-3,5-difluoroaniline was added
to three flasks in batches, and the mixture was maintained for
1.5 h at the temperature of 293.15 K. Then, 0.88 g of toluene-
p-sulfonic acid and an appropriate amount of inhibitor were
m1/M1
xi )
(1)
m1/M1 + m2/M2
where m1 and m2 represent the masses of the solute and solvent
and M1 and M2 are the molecular weights of the solute and the
solvent, respectively. All experiments were repeated three times,
and the solubility data were the average of experimental results.
Considering other factors, the relative uncertainty in the
measurement of the concentration of BDPM was within 0.5 %.
* Corresponding author. E-mail: guojiliu@zzu.edu.cn. Phone: 86 0371
67781101.
10.1021/je100819f  2011 American Chemical Society
Published on Web 12/14/2010

Journal of Chemical & Engineering Data, Vol. 56, No. 1, 2011 159
Figure 1. Synthesis of BDPM.
Table 1. Mole Fraction Solubility of BDPM in Different Solvents at
Different Temperatures
T
T
K
100x1 100(x1 - xc1alcd)/x1
K
100x1 100(x1 - xc1alcd)/x1
pyridine
tetrahydrofuran
285.55 1.16
289.66 1.29
293.95 1.44
297.15 1.54
300.85 1.69
304.65 1.86
310.05 2.14
315.65 2.46
318.65 2.65
322.55 2.91
328.45 3.41
334.15 3.94
337.95 4.32
340.65 4.62
344.85 5.14
346.35 5.33
-0.54
0.02
0.88
-0.31
0.04
-0.13
0.46
0.29
0.31
-0.03
0.76
0.79
0.38
0.06
0.13
285
1.48
-0.71
288.45 1.62
291.55 1.76
294.25 1.85
297.55 2.00
302.8
306.65 2.49
0.37
1.21
-0.26
-0.41
0.01
-0.27
-0.09
-0.40
-0.12
0.42
0.50
0.12
0.30
0.11
2.28
310.8
315
2.75
3.03
318.45 3.29
321.45 3.55
324.65 3.83
327.65 4.09
330.35 4.37
333.65 4.70
336.25 4.97
-0.13
-0.43
Figure 2. Solubilities of BDPM in different solvents: 9, pyridine; b,
acetone; 2, tetrahydrofuran; 1, ethanol; left tilted triangle, trichloromethane;
right tilted triangle, acetonitrile. The line is well fit to the experimental
data calculated with the modified Apelblat equation.
acetone
ethanol
0.03
0.03
0.04
0.06
0.08
0.11
0.14
0.16
0.20
0.23
0.27
0.30
0.33
0.36
0.39
287.65
291.85
295.55
298.35
301.25
304.55
307.6
309.45
311.95
313.95
316.55
319.55
321.45
323.35
325.15
0.71
0.81
0.92
1.00
1.09
1.20
1.31
1.39
1.52
1.59
1.74
1.90
2.02
2.14
2.25
-0.36
-0.62
0.79
0.48
0.43
288.65
293.59
299.85
305.72
311.15
318.15
324.35
327.85
332.95
336.05
339.65
341.85
344.15
346.15
347.75
4.45
6.33
-0.85
0.39
3.51
2.15
-0.97
-0.38
-1.23
-0.39
-1.61
0.54
-0.16
-0.03
0.89
Table 2. Parameters of the Modified Apelblat Equation for BDPM
in Different Pure Solvents
solvent
pyridine
tetrahydrofuran
acetone
ethanol
trichloromethane
acetonitrile
A
B
C
104 rmsd
0.04
-118.07
-82.66
-104.35
-117.39
-100.46
-95.91
3210.6
1702.2
2098.9
1238.0
1997.2
1223.0
18.11
12.82
16.27
18.50
15.59
15.12
1.24
1.17
0.68
0.20
0.59
1.00
-0.51
-0.78
0.67
-0.62
0.39
-0.25
0.47
0.15
and the BDPM is slightly soluble in ethanol, whereas the
solubility of BDPM in pure pyridine and tetrahydrofuran is
slightly higher than that in the solvents of ethanol, acetonitrile,
trichloromethane, and acetone. The temperature T dependence
of BDPM solubility in pure solvents can be computed by the
modified Apelblat equation
-0.27
trichloromethane
0.55
acetonitrile
0.28
0.33
0.37
0.40
0.44
0.49
0.57
0.70
0.78
0.95
1.07
1.19
1.46
1.65
1.98
2.17
289.25
294.85
296.65
300.85
302.75
305.65
307.45
309.55
311.65
315.35
318.65
322.15
324.65
326.45
328.35
330.65
-0.42
0.09
-0.38
0.17
-0.88
1.35
1.04
-0.69
0.21
291.95
296.65
299.25
302.45
304.85
307.15
311.55
316.95
320.15
325.45
328.55
332.05
338.65
341.65
347.25
350.15
1.41
-0.78
-0.61
-3.01
-2.02
-1.08
-0.99
0.29
-0.34
1.34
2.20
0.24
0.66
0.69
0.78
0.82
0.92
0.96
1.01
1.08
1.20
1.32
1.46
1.57
1.66
1.76
1.88
B
T/K
ln xc1alcd ) A +
+ C ln T/K
(2)
0.11
where A, B, and C are the empirical parameters. The experi-
mental data of mole fraction solubility in Table 1 were correlated
with eq 2.
The values of the three parameters, A, B, and C together with
the root-mean-square deviations (rmsd), are listed in Table 2.
The rmsd is defined as
-0.28
-0.42
-0.63
0.15
0.25
0.20
-1.27
0.72
0.02
-0.34
Results and Discussion
N
1
rmsf )
(xcalcd - xi)2}1/2
(3)
The solubility data of BDPM in pure pyridine, acetone,
tetrahydrofuran, ethanol, trichloromethane, and acetonitrile are
listed in Table 1 and shown in Figure 2. In Table 1, x1 expresses
the experimental solubility value. xc1alcd expresses the calculated
solubility value. From Table 1 and Figure 2, it can be seen that
at temperature ranging from (285.00 to 350.15) K, the solubility
of BDPM increases with temperature in all six pure solvents,
∑
i
{
N i)1
where N is the number of experimental points; xci alcd represents
the solubility calculated; and x1 represents the experimental
solubility values. As can be seen from Figure 2 and Table 2,
the correlation is satisfactory.

160 Journal of Chemical & Engineering Data, Vol. 56, No. 1, 2011
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ethanol, acetonitrile, trichloromethane, acetone, pyridine, and
tetrahydrofuran. The experimental solubility and correlation
equation in this work can be used as essential data and models
in the purification process of BDPM.
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Received for review August 9, 2010. Accepted November 24, 2010.
JE100819F