Vapor pressures and phase transitions of a series of the aminonaphthalenes

Article abstract of DOI:10.1021/je060394v

Vapor pressures of 1-aminonaphthalene, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, N,N-dimethyl-1-aminonaphthalene, 1,8-N,N,N,N',N'- tetramethyldiaminonaphthalene, and 1,5-N,N,N',N'-tetramethyldiaminonaphthalene have been determined by the transpiration method. The molar enthalpies of sublimation and the molar enthalpies of vaporization have been determined from the temperature dependence of the vapor pressure. Experimental vaporization and sublimation enthalpies were checked for internal consistency with help of available data on fusion enthalpies.

Full text of DOI:10.1021/je060394v

286
J. Chem. Eng. Data 2007, 52, 286-290
Vapor Pressures and Phase Transitions of a Series of the Aminonaphthalenes
Sergey P. Verevkin,* Miglena Georgieva,† and Svetlana V. Melkhanova‡
Department of Physical Chemistry, University of Rostock, 18051 Rostock, Germany
Vapor pressures of 1-aminonaphthalene, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, N,N-dimethyl-1-
aminonaphthalene, 1,8-N,N,N′,N′-tetramethyldiaminonaphthalene, and 1,5-N,N,N′,N′-tetramethyldiaminonaphthalene
have been determined by the transpiration method. The molar enthalpies of sublimation and the molar enthalpies
of vaporization have been determined from the temperature dependence of the vapor pressure. Experimental
vaporization and sublimation enthalpies were checked for internal consistency with help of available data on
fusion enthalpies.
Introduction
Certain aromatic diamines, such as 1,8-diaminonaphthalene
or 1,8-N,N,N′,N′-tetramethyldiaminonaphthalene (see Figure 1),
are found to have exceptionally high basicity constants: this is
due to spatial interaction of the basic centers, which are in close
proximity. Such compounds have been called the proton
sponges.1 The two factors that are most important in causing
this effect are, on the one hand, the extreme steric strain in these
systems and the destabilizing effect of the overlap of the nitrogen
lone pairs of the neutral diamines and, on the other hand, the
strong N‚‚‚H‚‚‚N hydrogen bonds that are formed on mono
protonation and that lead to a considerable relaxation of the
steric strain.1 The unusual properties of the proton sponges
Figure 1. Structures of aminonaphthalene derivatives and their Chemical
Abstracts Registry Numbers (CASRN): 1-aminonaphthalene (134-32-7);
1,8-diaminonaphthalene (479-7-6); 1,5-diaminonaphthalene (2243-62-1);
N,N-dimethyl-1-aminonaphthalene (86-56-6); 1,8-N,N,N′,N′-tetramethyl-
diaminonaphthalene (20734-58-1); 1,5-N,N,N′,N′-tetramethyldiaminonaph-
thalene (10075-69-1).
provide examples of the fact that cooperative steric interactions
of reactive structural elements can lead to properties that cannot
be derived from an isolated consideration of the various
functional groups. Such “proximity effects” are certainly of
general importance in chemistry and biochemistry. Thermo-
chemical methods provide quantitative data for interactions of
substituents on the naphthalene ring. In this work, we focus on
measuring of the vapor pressures, enthalpies of sublimation, and
enthalpies of vaporization of the naphthalene derivatives related
to the proton sponges shown in Figure 1.
of NaOH in water to a strongly basic solution with pH of 12
to 13, and the methylation product was extracted with
benzene. The benzene was evaporated, and the residue was
crystallized after 2 to 3 h. Yield was 6.41 g (94.7 %), melting
point was at 361 K. The compound was purified by repeated
re-crystallization from ethanol. The structure of the 1,5-
N,N,N′,N′-tetramethyldiaminonaphthalene was confirmed by
NMR spectroscopy.
Experimental Section
Samples of 1-aminonaphthalene, 1,8-diaminonaphthalene, 1,5-
diaminonaphthalene, N,N-dimethyl-1-aminonaphthalene, and
1,8-N,N,N′,N′-tetramethyldiaminonaphthalene were of com-
mercial origin (Aldrich, Fluka). The sample of 1,5-N,N,N′,N′-
tetramethyldiaminonaphthalene was prepared by methylation of
1,5-diaminonaphthalene according to procedures elaborated by
Sorokin et al.:2 a mixture of 23.9 mL of Me2SO4 (0.253 mol),
25 mL MeOH, and 72.3 g of Na2CO3‚10H2O (0.253 mol) was
added to 5.0 g of 1,5-diaminonaphthalene (0.032 mol). The
reaction mixture was stirred well (CO2 was evolved) for 5 h.
After that time, the reaction mixture was basified with solution
The degree of purity of all naphthalene derivatives studied
was determined using a Hewlett-Packard gas chromatograph
5890 series II equipped with a flame ionization detector and a
Hewlett-Packard 3390A integrator. The carrier gas (nitrogen)
flow was 12.1 cm3‚s-1. A capillary column HP-5 (stationary
phase crosslinked 5 % phenyl methyl silicone) was used with
a column length of 30 m, an inside diameter of 0.32 mm, and
a film thickness of 0.25 mm. The standard temperature program
of the GC was T ) 363 K for 180 s followed by a heating rate
of 0.167 K‚s-1 to T ) 523 K. No impurities (greater than mass
fraction 0.002) could be detected in the samples used for the
vapor pressure measurements. Melting temperature and enthalpy
of fusion of 1,8-diaminonaphthalene were determined with a
Perkin-Elmer DSC-2C.
* To whom correspondence concerning vapor pressures should be addressed.
E-mail: sergey.verevkin@uni-rostock.de. Phone: +49-381-498-6508.
Fax: +49-381-498-6502.
† On leave from the Institute of Organic Chemistry, Bulgarian Academy of
Sciences, Sofia, Bulgaria.
‡ On leave from the Chemistry Department, Moscow State University,
Moscow, Russia.
10.1021/je060394v CCC: $37.00 © 2007 American Chemical Society
Published on Web 11/23/2006

Journal of Chemical and Engineering Data, Vol. 52, No. 1, 2007 287
Vapor pressures were determined using the method of
transpiration in a saturated nitrogen stream,3,4 and enthalpies
of naphthalene derivatives were obtained applying the Clausius-
Clapeyron equation. About 0.5 g of the sample was mixed with
glass beads and placed in a thermostatted U-shaped tube having
a length of 20 cm and a diameter of 0.5 cm. Glass beads with
diameter of 1 mm provide surface, which was sufficient for the
vapor-liquid equilibration. At constant temperature (( 0.1 K),
a nitrogen stream was passed through the U-tube, and the
transported amount of gaseous material was collected in a
cooling trap. The flow rate of the nitrogen stream was measured
using a soap bubble flowmeter and optimized in order to reach
the saturation equilibrium of the transporting gas at each
temperature under study. On the one hand, flow rate of nitrogen
stream in the saturation tube should be not too slow in order to
avoid the transport of material from U-tube due to diffusion.
On the other hand the flow rate should be not too fast in order
to reach the saturation of the nitrogen stream with a compound.
We tested our apparatus at different flow rates of the carrier
gas in order to check the lower boundary of the flow below
which the contribution of the vapor condensed in the trap by
diffusion becomes comparable to the transpired one. In our
apparatus, the contribution due to diffusion was negligible at a
flow rate up to 0.11 cm3‚s-1. The upper limit for our apparatus
where the speed of nitrogen could already disturb the equilibra-
tion was at a flow rate of 1.5 cm3‚s-1. Thus, we carried out the
nitrogen was measured with gas-clock or by water withdrawing
from calibrated gasometer. Data of psiat have been obtained as a
function of temperature and were fitted using following equa-
tion:3
b
T
T
R ln psiat ) a + + ∆cgrCp ln
(2)
( )
T0
This equation was fitted to the experimental p, T data using a
and b as adjustable parameters. The T0 appearing in eq 2 is an
arbitrarily chosen reference temperature, which has been chosen
to be 298.15 K. Consequently from eq 2, the expression for the
sublimation enthalpy at temperature T is derived:
∆gcrHm(T) ) -b + ∆cgrCpT
(3)
Experimental results with parameters a and b are listed in
Table 1. Values of ∆g Cp have been derived according to a
cr
procedure developed by Chickos et al.5 When the vapor
pressures were measured over liquid samples of aminonaph-
thalene derivatives, eq 2 gives the expression for the vaporization
enthalpy ∆gHm at temperature T. Values of ∆gCp required for
l
l
the data treatment in this case have been derived according to
a procedure developed by Chickos and Acree.6 We have checked
experimental and calculation procedure with measurements of
vapor pressures of n-alcohols3 and substituted naphthalenes.7
It turned out that vapor pressures derived from the transpiration
method were reliable within (1 to 3) % and that their accuracy
was governed by reproducibility of the GC analysis. Contribu-
tions to the experimental error due to fluctuations of the nitrogen
stream or temperature were negligible in comparison to the
aforementioned error bars of the GC analysis. In order to assess
the uncertainty of the vaporization enthalpy, the experimental
data were approximated with the linear equation ln(psiat) )
f (T -1) using the method of least squares. The uncertainty in
the enthalpy of vaporization was assumed to be identical with
the as average deviation of experimental ln(psiat) values from
this linear correlation.
experiments in the flow rate interval of (0.28 to 0.52) cm3‚s-1
,
which has ensured that transporting gas was in saturated
equilibrium with the coexisting liquid phase in the saturation
tube. The mass of compound collected within a certain time
interval was determined by dissolving it in a suitable solvent
with a known amount of external standard (hydrocarbon). This
solution was analyzed using a gas chromatograph equipped with
autosampler. Uncertainty of the sample amount determined by
GC analysis was assessed to be within (1 to 3) %. The peak
area of the compound related to the peak of the external
standard (hydrocarbon n-CnH2n+2) is a direct measure of the
mass of the compound condensed into the cooling trap provided
a calibration run has been made. From this information the vapor
pressure of the compound under study can be determined (i.e.,
the ideal gas law can be applied provided that the vapor pressure
of the substance is low enough). Real gas corrections arising
from interactions of the vapor with the carrier gas were
negligible. The saturation vapor pressure psiat at each tempera-
ture Ti was calculated from the amount of product collected
within a known period of time, and the small value of the
residual vapor pressure at the temperature of condensation was
added. The latter was calculated from a linear correlation
Results and Discussion
Vapor pressure measurements on 1,8-diaminonaphthalene,
1,5-diaminonaphthalene, N,N-dimethyl-1-aminonaphthalene, 1,8-
N,N,N′,N′-tetramethyldiaminonaphthalene, and 1,5-N,N,N′,N′-
tetramethyldiaminonaphthalene have been performed for the first
time. Critical evaluation of the available thermochemical
properties for 1- and 2-aminonaphthalene was reported by Das
et al.,8 but the phase transitions data on these species is
apparently in disarray. Indeed, Das et al.8 recommended the
value ∆gcrHm ) (65.0 ( 4.0) kJ‚mol-1 for 1-aminonaphthalene.
This enthalpy of sublimation was assessed from the selected
sat
-1
between ln(pi ) and T obtained by iteration. Assuming that
Dalton’s law of partial pressures applied to the nitrogen stream
saturated with the substance i of interest is valid, values of pisat
were calculated:
value ∆g Hm ) (74.1 ( 4.0) kJ‚mol-1 measured by Karyakin
cr
et al.9 (using an effusion method) and the difference between
enthalpies of fusion of 1- and 2-aminonaphthalene 9.1 kJ‚mol-1
reported by Khetarpal et al.10 (see Table 2). Thus, the estimate
by Das et al.8 of ∆cgrHm ) (65.0 ( 4.0) kJ‚mol-1 and our result
psiat ) miRTa/VMi; V ) VN2 + Vi; (VN2 . Vi)
(1)
where R ) 8.314472 J‚K-1‚mol-1, mi is the mass of transported
compound, Mi is the molar mass of the compound, and Vi is its
volume contribution to the gaseous phase. VN2 is the volume of
transporting gas, and Ta is the temperature of the soap bubble
meter. The volume of transporting gas VN2 was determined from
the flow rate and time measurements. The flow rate was
maintained constant with help of the high precision needle valve
(Hoke, C1335G6BMM-ITA). The accuracy of the volume VN2
measurements from flow rate was established to be (( 0.001
dm3) with help of series of experiments, where volume the
∆g Hm ) (88.1 ( 0.4) kJ‚mol-1 from Table 1 are different
cr
over 20 kJ‚mol-1. The value ∆cgrHm ) (90.0 ( 4.2) kJ‚mol-1
cited in the NIST WebBook11 as the experimental result from
Balson12 should support our result, but unfortunately this
reference does not contain any data on 1-aminonaphthalene. The
comprehensive compilation by Stull13 contains vapor pressure
data for 1- and 2-aminonaphthalene over a wide range of
temperature from 377 K to their boiling point. It should be
mentioned, that the origin of the data presented there is unclear,

288 Journal of Chemical and Engineering Data, Vol. 52, No. 1, 2007
Table 1. Vapor Pressures p, Sublimation Enthalpy ∆g Hm, and Vaporization Enthalpy ∆gHm Obtained by the Transpiration Method
cr
l
T
Ka
m
mgb
V(N2) N2 flow
dm3 c cm3‚s-1
p
Pad
(pexp - pcalc
)
∆g Hm or ∆gHm
kJ‚mol-1
T
Ka
m
mgb
V(N2) N2 flow
dm3 c cm3‚s-1
p
Pad
(pexp - pcalc
)
∆g Hm or ∆gHm
kJ‚mol-1
cr
l
cr l
Pa
Pa
1-Aminonaphthalene(cr), ∆gcrHm(298.15 K) ) (88.11 ( 0.40) kJ‚mol-1
307.1 95978.9 26.4
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
290.3 0.56 153.5
293.3 0.57 104.6
298.3 1.06 107.3
7.03
7.23
6.84
7.13
6.74
0.06
0.09
0.17
0.30
0.55
0.00
0.00
0.00
-0.01
0.01
88.32
88.24
88.11
87.97
87.84
311.5 0.67 15.11
314.2 0.79 13.22
316.2 1.07 14.88
318.2 1.02 11.23
6.74
6.84
6.84
6.84
6.84
0.76
1.03
1.24
1.55
1.91
0.00
0.01
-0.03
-0.01
-0.01
87.76
87.69
87.63
87.58
87.53
303.3 0.44
308.3 0.59
25.19
18.54
320.2 0.84
7.58
1-Aminonaphthalene(l), ∆lgHm(298.15 K) ) (73.29 ( 0.43) kJ‚mol-1
313.2 96542.6 78.0
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
323.2 0.87
326.2 0.96
329.2 1.04
332.3 1.48
335.3 1.22
338.1 1.16
5.46
4.73
4.12
4.73
3.03
2.31
7.28
7.28
7.28
7.28
7.28
7.28
2.71
3.44
4.29
5.33
6.83
8.59
0.04
0.03
-0.04
-0.18
-0.09
0.07
71.34
71.10
70.87
70.63
70.39
70.17
341.1 1.12
344.1 1.04
347.1 1.17
350.1 1.13
353.1 0.86
1.82
1.33
1.21
0.971
0.607
7.28
7.28
7.28
7.28
7.28
10.53
13.27
16.44
19.91
24.28
-0.08
0.12
0.20
-0.04
-0.13
69.94
69.71
69.47
69.24
69.00
1,8-Diaminonaphthalene(cr), ∆gcrHm(298.15 K) ) (94.08 ( 0.37) kJ‚mol-1
303.5 102520.6 28.3
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
304.4 0.19 174.6
4.94
4.94
4.94
4.88
4.88
4.94
4.94
4.94
4.88
4.94
4.88
0.017
0.024
0.034
0.051
0.061
0.086
0.101
0.130
0.152
0.162
0.210
0.000
0.000
0.000
0.001
0.001
93.91
93.83
93.74
93.65
93.60
93.52
93.46
93.40
93.37
93.35
93.28
327.2 0.20 14.04
329.1 0.21 12.00
330.2 0.27 14.08
331.2 0.27 12.44
4.94
4.88
4.94
4.88
4.94
4.94
4.88
4.94
4.94
4.94
0.223
0.273
0.302
0.339
0.348
0.372
0.414
0.422
0.526
0.535
0.001
0.002
-0.001
0.003
-0.010
0.000
0.002
-0.011
0.022
93.26
93.21
93.18
93.15
93.13
93.12
93.09
93.08
93.04
93.02
307.3 0.15
310.3 0.19
313.6 0.23
315.2 0.26
318.2 0.40
320.3 0.19
322.2 0.22
323.5 0.15
324.2 0.17
326.5 0.18
96.2
87.52
71.29
67.91
71.63
29.39
27.01
15.01
15.97
13.18
331.8 0.15
332.2 0.22
333.2 0.18
333.7 0.14
335.2 0.23
335.7 0.19
6.67
9.39
6.91
5.19
6.71
5.52
0.002
-0.005
-0.001
0.002
0.000
0.004
0.005
1,8-Diaminonaphthalene(l), ∆gl Hm(298.15 K) ) (79.57 ( 0.25) kJ‚mol-1
322.9 106943.6 91.8
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
339.5 0.22
341.5 0.20
344.6 0.28
346.1 0.20
349.3 0.22
352.4 0.26
355.3 0.33
358.5 0.31
5.44
4.32
4.86
2.99
2.70
2.49
2.49
1.91
4.98
4.98
4.98
4.98
4.98
4.98
4.98
4.98
0.62
0.72
0.91
1.03
1.28
1.62
2.03
2.50
0.01
0.00
0.00
75.78
75.60
75.31
75.18
74.88
74.60
74.33
74.04
361.4 0.44
364.5 0.37
367.6 0.49
370.6 0.44
373.2 0.41
376.2 0.39
379.3 0.36
2.32
1.54
1.66
1.20
0.955
0.747
0.581
4.98
4.98
4.98
4.98
4.98
4.98
4.98
2.95
3.73
4.59
5.67
6.63
8.04
9.66
-0.11
-0.04
-0.04
0.06
0.02
0.07
73.77
73.49
73.20
72.93
72.69
72.41
72.13
0.01
-0.01
-0.01
0.02
0.03
0.00
1,5-Diaminonaphthalene(cr), ∆gcrHm(298.15 K) ) (120.16 ( 0.65) kJ‚mol-1
340.9 128595.7 28.3
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
345.3 0.10 113.1
347.3 0.12 104.6
4.81
4.81
4.81
4.81
4.81
4.81
4.81
4.81
4.81
0.0139
0.0175
0.0221
0.0242
0.0272
0.0350
0.0383
0.0442
0.0540
0.0003
0.0002
0.0002
-0.0004
-0.0004
0.0002
-0.0006
0.0006
-0.0006
118.83
118.77
118.71
118.68
118.66
118.60
118.57
118.54
118.49
359.3 0.13 31.47
360.4 0.43 90.59
361.3 0.14 26.21
363.4 0.16 23.97
366.4 0.23 24.69
368.4 0.23 20.12
369.3 0.29 22.05
371.3 0.32 20.04
4.81
4.81
4.81
4.81
4.81
4.81
4.81
4.81
0.0656
0.0741
0.0856
0.1051
0.1455
0.1808
0.2045
0.2502
-0.0026
-0.0028
0.0007
-0.0015
-0.0014
-0.0005
0.0053
118.43
118.40
118.37
118.31
118.23
118.17
118.15
118.09
349.3 0.13
350.3 0.14
351.3 0.15
353.3 0.17
354.3 0.21
355.3 0.17
357.3 0.25
89.07
89.55
83.77
73.83
84.74
60.45
71.59
0.0051
N,N-Dimethyl-1-aminonaphthalene(l), ∆gl Hm(298.15 K) ) (66.92 ( 0.16) kJ.mol-1
311.6 92676.0 86.4
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
283.2 0.67
285.2 0.99
287.7 1.30
291.3 1.21
295.3 0.45
298.2 0.55
304.2 0.43
307.3 1.34
310.3 0.65
37.68
45.10
45.45
30.17
7.92
7.56
3.36
4.69
4.69
4.69
4.69
4.75
4.75
4.69
4.91
4.91
0.26
0.32
0.41
0.58
0.83
1.05
1.84
2.45
3.05
0.00
0.00
0.01
68.16
68.00
67.78
67.48
67.14
66.90
66.39
66.13
65.88
313.3 0.81
316.3 0.81
319.4 0.91
322.2 0.85
325.3 0.91
328.2 1.07
331.2 1.26
334.3 1.15
3.01
2.34
2.03
1.56
1.33
1.25
1.17
4.69
4.69
4.69
4.69
4.69
4.69
4.69
4.69
3.89
4.97
6.42
7.85
9.89
12.34
15.45
19.29
-0.07
-0.05
0.03
-0.05
-0.07
0.05
65.62
65.37
65.11
64.87
64.61
64.37
64.11
63.85
0.01
-0.01
-0.04
-0.01
0.04
0.24
0.42
7.90
3.07
0.860
-0.05

Journal of Chemical and Engineering Data, Vol. 52, No. 1, 2007 289
Table 1 (Continued)
T
Ka
m
mgb
V(N2) N2 flow
dm3 c cm3‚s-1
p
Pad
(pexp - pcalc
)
∆g Hm or ∆gHm
kJ‚mol-1
T
Ka
m
mgb
V(N2) N2 flow
dm3 c cm3‚s-1
p
Pad
(pexp - pcalc
)
∆g Hm or ∆gHm
cr l
kJ‚mol-1
cr
l
Pa
Pa
1,8-N,N,N′,N′-Tetramethyldiaminonaphthalene(cr), ∆gcrHm(298.15 K) ) (94.73 ( 0.80) kJ‚mol-1
353.5 110587.2 53.2
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
290.7 0.50 125.5
5.92
5.95
5.92
5.90
5.75
5.95
0.045
0.065
0.094
0.124
0.126
0.192
-0.001
95.12
94.99
94.84
94.72
94.70
94.56
304.3 0.71 29.98
306.7 0.59 19.25
308.4 0.66 17.50
308.5 0.90 22.34
310.9 0.76 14.99
5.88
5.80
5.90
5.80
5.88
5.80
0.270
0.343
0.433
0.454
0.576
0.802
0.005
-0.011
-0.002
0.015
-0.008
-0.006
94.40
94.27
94.18
94.18
94.05
93.90
293.2 0.49
296.1 0.73
298.3 0.27
298.7 0.47
301.4 0.46
83.82
88.69
24.88
42.09
26.95
0.001
0.000
-0.001
-0.005
0.007
313.7 0.62
8.70
1,8-N,N,N′,N′-Tetramethyldiaminonaphthalene(l), ∆gl Hm(298.15 K) ) (76.72 ( 0.35) kJ‚mol-1
351.8 109097.1 108.9
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
323.7 1.37
326.2 1.48
329.2 1.51
332.1 1.61
333.3 0.86
334.5 1.11
337.5 1.16
340.3 1.23
7.65
6.61
5.35
4.48
2.18
2.61
2.19
1.91
3.45
3.45
3.45
3.45
3.08
3.37
3.37
3.37
2.04
2.54
3.20
4.08
4.47
4.84
5.99
7.33
0.03
0.06
0.02
0.07
0.06
-0.01
-0.12
-0.23
73.95
73.68
73.35
73.04
72.91
72.78
72.45
72.15
343.4 1.47
346.3 1.63
349.2 1.56
352.3 1.60
355.2 2.16
358.4 2.46
361.2 2.59
364.3 3.01
1.77
1.61
1.26
1.03
1.09
1.01
0.891
0.863
3.37
3.45
3.45
3.45
3.45
3.45
3.45
3.45
9.46
11.52
13.97
17.56
22.50
27.75
32.98
39.66
-0.05
-0.21
-0.44
-0.32
0.72
0.81
0.66
71.81
71.49
71.18
70.84
70.53
70.18
69.88
69.54
0.28
1,5-N,N,N′,N′-Tetramethyldiaminonaphthalene(cr), ∆gcrHm(298.15 K) ) (98.55 ( 0.40) kJ‚mol-1
348.0 114416.0 53.2
T/K
298.15
ln(p/Pa) )
-
-
ln
(
)
R
R
R(T/K)
318.2 0.53
322.2 0.61
325.2 0.69
326.7 0.51
328.1 0.58
328.2 0.61
329.6 0.60
330.6 0.58
331.2 0.59
331.9 0.62
332.7 0.47
333.5 0.64
335.7 0.60
338.1 0.63
37.59
27.32
22.42
13.76
13.78
14.64
11.94
10.91
9.33
9.67
6.82
8.27
6.35
3.13
5.46
5.61
5.58
5.51
5.49
5.51
5.46
5.60
5.52
4.54
5.22
5.44
5.21
0.165
0.262
0.360
0.432
0.493
0.491
0.591
0.625
0.733
0.751
0.809
0.899
1.104
1.407
0.002
0.004
0.001
97.49
97.28
97.12
97.04
96.96
96.96
96.88
96.83
96.80
96.76
96.72
96.68
96.56
96.43
338.2 0.41
339.2 0.62
340.7 0.60
341.3 0.61
343.2 0.69
344.4 0.55
345.7 0.69
348.2 0.63
349.5 0.60
350.7 0.58
351.5 0.59
353.2 0.62
354.5 0.57
355.7 0.63
3.33
4.74
4.09
3.63
3.45
2.49
2.71
1.90
1.67
1.42
1.34
1.18
2.66
5.69
5.46
5.18
4.60
5.53
5.42
4.57
2.86
2.83
2.86
2.83
2.86
2.80
1.440
1.532
1.739
1.952
2.351
2.574
3.001
3.918
4.230
4.832
5.213
6.210
6.941
7.956
0.015
-0.045
-0.093
-0.002
0.004
-0.066
0.007
0.113
-0.075
0.013
0.020
0.131
0.091
0.314
96.43
96.37
96.29
96.26
96.16
96.10
96.03
95.89
95.83
95.76
95.72
95.63
95.56
95.50
0.008
-0.002
-0.009
0.010
-0.025
0.044
0.009
0.002
0.021
0.000
0.955
0.934
5.21
-0.003
a Temperature of saturation. b Mass of transferred sample, condensed at T ) 243 K. c Volume of nitrogen, used to transfer mass m of sample. d Vapor
pressure at temperature T, calculated from m and the residual vapor pressure at T ) 243 K.
Table 2. Comparison of Enthalpies of Fusion Measured by DSC with Those Calculated as the Difference ∆l Hm ) ∆g Hm
-
cr
cr
∆gHm at T ) 298 K from Transpirationa
l
∆g Hm
∆gHm
∆l Hm
actrTfus
∆l Hm
∆l Hm
b
b
c
d
e
cr
l
at c2r98 K
at c2r98 K
kJ·mol-1
6
∆
f
at 298.15 K
at 298 K
compound
kJ‚mol-1
kJ‚mol-1
kJ‚mol-1
kJ‚mol-1
kJ·mol-1
1
2
3
4
5
7
1-aminonaphthalene (I)
88.11 ( 0.40
73.29 ( 0.43
14.49/323.2 K10
15.33/323.2 K8
16.18/323 K14
23.61/386.210
12.5
13.4
14.2
19.1
73.613
14.9
14.5
18.0
-0.7
-1.0
-1.8
2-aminonaphthalene
93.7g
74.613
74.1 ( 1.79,11
94.08 ( 0.37
120.16 ( 0.65
II
79.57 ( 0.25
16.15h/339.8
25.5i/469.5 K
13.5
14.6
III
IV
V
66.92 ( 0.16
76.72 ( 0.35
94.73 ( 0.80
98.55 ( 0.40
17.6i/324 K
19.6i/361 K
16.2
16.2
VI
a 1-Aminonaphthalene (I); 1,8-diaminonaphthalene (II); 1,5-diaminonaphthalene (III); N,N-dimethyl-1-aminonaphthalene (IV); 1,8-N,N,N′,N′-tetrameth-
yldiaminonaphthalene (V); 1,5-N,N,N′,N′-tetramethyldiaminonaphthalene (VI). b Results from this work (see Table 1). c The enthalpy of fusion ∆cl rHm
measured by DSC. d The enthalpy of fusion ∆lcrHm measured by DSC and extrapolated to 298.15 K (see text). e The enthalpy of fusion ∆cl rHm, calculated as
the difference ∆g Hm - ∆gHm from Table 1. f The difference between columns 5 and 6. g Calculated as the sum of columns 3 and 4. h The enthalpy of fusion
cr
l
measured in this work using DSC-2, Perkin-Elmer (calibrated with indium). i Calculated using the modified15 Walden’s rule: ∆l Hm(Tfus) ) 54.4
cr
(J‚K-1mol-1)‚Tfus (K).
methods of measurements are unknown, as well as are errors
of measurements and purities of compounds. In spite of this
fact, we treated the results from Stull13 using eqs 2 and 3 and
calculated enthalpies of vaporization for the sake of comparison

290 Journal of Chemical and Engineering Data, Vol. 52, No. 1, 2007
with our results: ∆lgHm(298.15 K) ) 73.6 kJ‚mol-1 for
1-aminonaphthalene and ∆gl Hm(298.15 K) ) 74.6 kJ‚mol-1 for
2-aminonaphthalene. These results look quite reasonable, be-
cause according our previous findings for 1- and 2 substituted
naphthalenes, their enthalpies of vaporization usually differ by
only (1 to 2) kJ‚mol-1. Direct comparison of vapor pressures
reported by Stull13 with those in this work (Table 1) is not
possible because of completely different temperature ranges,
298.15 K are required to obtain gaseous enthalpies of formation
∆fH°(g) of organic compounds, provided that their enthalpies
m
of formation in condensed phase ∆fH°(l or cr) are known.
m
Experimental values for ∆fH°(l or cr) of the same series of
m
aminonaphthalenes from combustion calorimetry will be a
subject of our forthcoming paper.
Literature Cited
but the agreement of vaporization enthalpies ∆gHm(298.15 K)
l
(1) Pozharskii, A. F. Naphthalene proton sponges. Russ. Chem. ReV. 1998,
67, 1-24.
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effective procedure for the N-permethylation of amino-substituted
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(3) Kulikov, D. V.; Verevkin, S. P.; Heintz, A. Enthalpies of vaporization
of a series of linear aliphatic alcohols. Experimental measurements
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(4) Verevkin, S. P. Pure component phase changes liquid and gas. In
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(5) Chickos, J. S.; Hesse, D. G.; Liebman, J. F. A group additivity
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(6) Chickos, J. S.; Acree, W. E., Jr. Enthalpies of vaporization of organic
and organometallic compounds, 1880-2002. J. Phys. Chem. Ref. Data
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(7) Verevkin, S. P. Vapor pressures and enthalpies of vaporization of a
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(8) Das, A.; Frenkel, M.; Gadalla, N. A. M.; Kudchadker, S.; Marsh, K.
N.; Rodgers, A. S.; Wilhoit, R. C. Thermodynamic and thermophysical
properties of organic nitrogen compounds. Part II. 1- and 2-Butan-
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2-, and 3-methylpyrrole, pyridine, 2-, 3-, and 4-methylpyridine,
pyrrolidine, piperidine, indole, quinoline, isoquinoline, acridine, car-
bazole, phenanthridine, 1- and 2-naphthalenamine, and 9- methylcar-
bazole. J. Phys. Chem. Ref. Data 1993, 22, 659-782.
derived from vapor pressures in both studies is very close (see
Table 2). In addition, results from this work together with the
vapor pressures reported by Stull13 led us to claim ∆g Hm
)
cr
(74.1 ( 4.0) kJ‚mol-1 for 2-aminonaphthalene measured by
Karyakakin et al.9 as unreliable and instead to suggest the
more arguable value ∆cgrHm(298.15 K) ) 93.7 kJ‚mol-1 calcu-
lated from ∆gl Hm(298.15 K) ) 74.6 kJ‚mol-1 for 2-amino-
naphthalene derived in this work from results by Stull13 and
the fusion enthalpy for this compound reported by Khetarpal et
al.10 and adjusted to the reference temperature 298.15 K (see
Table 2).
A valuable test of consistency of the experimental data on
sublimation and vaporization enthalpies measured in this work
provides a comparison with a set of experimental values of
enthalpies of fusion of the solid aminonaphthalenes (see Table
2). Indeed, in this work, most of the solid aminonaphthalenes
were investigated by the method of transference in both ranges,
above and below the temperature of fusion and the values
∆g Hm(298.15 K) and ∆gHm(298.15 K) were derived (see
cr
l
Tables 1 and 2). For each compound studied, comparison (see
Table 2) of the enthalpy of fusion, ∆l Hm, calculated as the
cr
difference ∆g Hm - ∆gHm (both values referred to T ) 298.15
cr
l
K) from Table 1, and the enthalpy of fusion ∆l Hm measured at
cr
Tfus (and adjusted to T ) 298.15 K, see below) demonstrate
discrepancies only on the level of (1 to 2) kJ‚mol-1 and are
acceptable within the boundaries of the experimental uncertain-
ties of the methods used. Hence, the set of vaporization and
sublimation enthalpies of aminonaphthalenes given in the Table
1 possess the internal consistency.
(9) Karyakin, N. V.; Rabinovich, I. B.; Pakhomov, L. G. Heats of
sublimation of naphthalene and its beta-monoderivatives. Zh. Fiz.
Khim. 1968, 42, 1814-1816.
(10) Khetarpal, S. C.; Lal, K.; Bhatnagar, H. L. Thermodynamic studies
on melting of some alpha- and beta-derivatives of naphthalene. Austr.
J. Chem. 1979, 32, 49-57.
(11) Brown, R. L.; Stein, S. E. Boiling point data. In NIST Chemistry
WebBook; NIST Standard Reference Database No. 69; Linstrom, P.
J., Mallard, W. G., Eds.; National Institute of Standards and Technol-
ogy: Gaithersburg, MD, June 2005; http://webbook.nist.gov.
(12) Balson, E. W. Studies in vapor pressure measurement. Part III. An
effusion manometer sensitive to 5 × 10-6 millimeters of mercury:
vapor pressure of D.D.T. and other slightly volatile substances. Trans.
Faraday Soc. 1947, 43, 54-60.
The experimental enthalpies of fusion ∆l Hm are referred to
cr
the melting temperature and are recorded in Table 2. Because
of the deviations from T ) 298.15 these observed values of the
enthalpies of fusion of aminonaphthalenes had to be corrected
to this reference temperature. The corrections were estimated
with help of the equation:5,6
(13) Stull, D. R. Vapor pressure of pure substances organic compounds.
Ind. Eng. Chem. 1947, 39, 517-540.
{∆lcrHm(Tfus/K) - ∆cl rHm(298.15 K)}/(J‚mol-1) )
{(0.75 + 0.15Ccpr)[(Tfus/K) - 298.15]} -
{(10.58 +0.26Clp)[(Tfus/K) - 298.15]} (4)
(14) Tiers, G. V. D. Materials science of organic compounds. Part 3. Glass-
formers, vitriphores, Tg, and molecular chirality. Thermochim. Acta
1993, 226, 317-324.
(15) Chickos, J. S.; Acree, W. E., Jr.; Liebman, J. F. Estimating solid-
liquid change enthalpies and entropies. J. Phys. Chem. Ref. Data 1999,
28, 1535-1673.
With these corrections and the measured values of ∆l Hm(Tfus),
cr
the standard molar enthalpies of fusion at T ) 298.15 K,
Received for review September 6, 2006. Accepted October 11, 2006.
S.P.V. gratefully acknowledges financial support from the Research
Training Group “New Methods for Sustainability in Catalysis and
Technique” of German Science Foundation (DFG). M.G. gratefully
acknowledges a research scholarship from the Bulgarian Ministry of
∆l Hm(298.15 K), were calculated (Table 2).
cr
The experimental vapor pressures, enthalpies of sublimation,
enthalpies of vaporization, and enthalpies of fusion of amino-
naphthalenes fill a gap in our knowledge of the thermochemical
data for “proton sponges”. Values of enthalpies of vaporization
∆gHm or sublimation ∆g Hm at the reference temperature
Science and Education. S.V.M. gratefully acknowledges
scholarship from DAAD.
a research
JE060394V
l
cr