Thermochemistry of organic azides revisited Dedicated to Prof. Ch. Rüchardt on the Occasion of His 85th Birthday

Article abstract of DOI:10.1016/j.tca.2014.10.015

Highly pure samples of 4-nitro-phenyl azide, 1-octyl azide and 1 decyl-azide were prepared for thermochemical studies. Vapour pressures over the solid and the liquid sample of 4-nitro-phenyl azide have been determined by the transpiration method. The molar enthalpies of vaporization/sublimation for this compound were derived from the temperature dependencies of vapour pressures. The molar enthalpy of fusion of 4-nitro-phenyl azide was measured by DSC. The measured data set for 4-nitro-phenyl azide was successfully checked for internal consistency. Molar enthalpies of vaporization of 1-octyl azide and 1 decyl-azide were measured by transpiration. The molar enthalpies of formation of the liquid 1-octyl azide and 1 decyl-azides were derived from the combustion calorimetry. New experimental results for these organic azides have been used to derive their molar enthalpies of formation in the gas state and for comparison with results from quantum-chemical method G4.

Full text of DOI:10.1016/j.tca.2014.10.015

Thermochimica Acta 597 (2014) 78–84
Contents lists available at ScienceDirect
Thermochimica Acta
journal homepage: www.elsevier.com/locate/tca
Thermochemistry of organic azides revisited
a
b
c
Vladimir N. Emel`yanenko , Manuel Algarra , Joaquim C.G. Esteves da Silva ,
a
c
a,d,
Jesús Hierrezuelo , Juan M. López-Romero , Sergey P. Verevkin
Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan, Russia
Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
Department of Physical Chemistry and Department “Science and Technology of Life, Light and Matter”, University of Rostock, Dr-Lorenz-Weg 1, D-18059,
*
a
b
c
d
Rostock, Germany
A R T I C L E I N F O
A B S T R A C T
Article history:
Received 18 August 2014
Received in revised form 8 October 2014
Accepted 15 October 2014
Available online 18 October 2014
Highly pure samples of 4-nitro-phenyl azide, 1-octyl azide and 1 decyl-azide were prepared for
thermochemical studies. Vapour pressures over the solid and the liquid sample of 4-nitro-phenyl azide
have been determined by the transpiration method. The molar enthalpies of vaporization/sublimation for
this compound were derived from the temperature dependencies of vapour pressures. The molar
enthalpy of fusion of 4-nitro-phenyl azide was measured by DSC. The measured data set for 4-nitro-
phenyl azide was successfully checked for internal consistency. Molar enthalpies of vaporization of 1-
octyl azide and 1 decyl-azide were measured by transpiration. The molar enthalpies of formation of the
liquid 1-octyl azide and 1 decyl-azides were derived from the combustion calorimetry. New experimental
results for these organic azides have been used to derive their molar enthalpies of formation in the gas
state and for comparison with results from quantum-chemical method G4.
Dedicated to Prof. Ch. Rüchardt on the
Occasion of His 85th Birthday
Keywords:
Vapour pressure
Enthalpy of vaporization
Enthalpy of sublimation
Enthalpy of formation
Transpiration method
Combustion calorimetry
DSC
ã 2014 Elsevier B.V. All rights reserved.
Azide
1. Introduction
2. Experimental
Organic azides have a broad field of application as propellants,
plasticizers and pharmacy products [1]. Thermochemical data for
azides are in disarray [2]. Most of enthalpies of formation and
enthalpies of sublimation/vaporization available in the literature
are of technical quality or reported without any sample purity
information. Nowadays, the modern quantum-chemical methods
allow for performing the enthalpy data evaluation, provided that
sufficient amount of the experimental data with the benchmark
quality are available for the methods attestation. This paper
extends our previous experimental study of a series of organic
azides [3]. A complex thermochemical studies (including transpi-
ration, combustion calorimetry and DSC) on highly pure samples of
2.1. Materials
Samples of 4-nitro-phenyl azide, 1-octyl azide and 1 decylazide
were prepared and purified at the University of Málaga, according
to the literature procedures with some modifications.
2.1.1. 4-Nitro-phenyl azide
In a round bottom flask equipped with a magnetic stirrer, a
sample of 4-nitroaniline (1 g, 7.25 mmol) was dissolved in 5 mL of
HCl and 5 mL of water. 10 mL of cold aqueous solution of sodium
nitrite (0.5 g, 7.25 mmol) was dropped into the flask under stirring
at 273 K. Then, 12 mL of aqueous solution of sodium azide (0.47 g
7.25 mmol) was dropped into the flask and the reaction was
allowed to continue for 30 min. The precipitate was extracted with
chloroform and washed with water. The organic layer was dried
over anhydrous sodium sulphate, and the solvent was evaporated
4-nitro-phenyl azide, 1-octyl azide and 1 decyl-azide. These new
data are expected to help for validation of the high-level quantum-
chemical calculations.
l
in vacuo to get 4-nitro-phenyl azide, yield 90% (1.07 g) [4], H NMR
(
400 MHz, CDCl
C NMR (100 MHz, CDCl
3
):
d
8.18 (d, J = 9.2 Hz, 2H), 7.09 (d, J = 9.2 Hz, 2H).
): 146.8, 144.5, 125.5, 119.3.
*
Corresponding author. Tel.: +49 381 498 6508.
E-mail address: sergey.verevkin@uni-rostock.de (S.P. Verevkin).
1
3
3
d
http://dx.doi.org/10.1016/j.tca.2014.10.015
040-6031/ã 2014 Elsevier B.V. All rights reserved.
0

V.N. Emel`yanenko et al. / Thermochimica Acta 597 (2014) 78–84
79
2
.1.2. 1-Octyl azide
The amount of condensed sample of 1-octyl azide and 1 decyl-
azide was determined by GC analysis using an external standard
NaN (2.53 g, 38.86 mmol) was added to a solution of 1-
3
bromooctane (5 g, 25.91 mmol) in dimethylformamide (10 mL).
The reaction mixture was stirred at room temperature for 4 h.
Water (100 mL) was added to the reaction mixture and the aqueous
layer was extracted with ethyl acetate (3 ꢀ 50 mL). The combined
organic phase was washed with 100 mL brine (26% of NaCl in MilliQ
(n-C
nitro-phenyl azide was determined by weighing of the trap
(ꢃ0.0001 g). The absolute vapour pressure p at each temperature
was calculated from the amount of the product collected within a
8
H18 and n-C11H24). The amount of condensed sample of 4-
i
T
i
definite period of time. Assuming validity of the Dalton’s law
Water, pH 6.8), dried over anhydrous Na
reduced pressure to give azide (3.5 g, 87%) as a colourless oil. H
NMR (400 MHz, CDCl ): 3.25 (t, J = 6.9 Hz, 2H), 1.60 (quin,
J = 6.7 Hz, 2H), 1.28 (br s, 10H), 0.80 (t, J = 6.4 Hz, 3H).
2
SO
4
and evaporated at
applied to the nitrogen stream saturated with the substance i,
values of p were calculated with equation:
i
l
3
d
m ꢀ R ꢀ T
a
i
pi ¼
; V ¼ VN2 þ V ; VN2 ꢄ Vi
(1)
i
V ꢀ M
i
2
.1.3. 1-Decyl azide
ꢂ1
ꢂ1
NaN (5.25 g, 80 mmol) and 1-bromo-decane (7.08 g, 32 mmol)
3
where R = 8.314472 J K mol ; m
compound, M
volume contribution to the gaseous phase. VN2 is the volume of the
carrier gas and T is the temperature of the soap bubble meter used
i
is the mass of the transported
were dissolved in acetone: H
2
O (10:1), and left stirred for 3 days
i i
is the molar mass of the compound, and V ; its
ꢁ
under reflux at 65 C. The extraction procedure of the azide was
carried out with diethyl ether (3 ꢀ 50 mL) and dichloromethane
a
(
2 ꢀ 50 mL). To ensure the total extraction and absence of H
2
O, the
for measurement of the gas flow. The volume of the carrier gas VN2
was determined from the flow rate and the time measurement.
Experimental results are given in Tables 2 and 3.
organic phase was washed with brine (26% of NaCl in MilliQ Water,
pH 6.8), dried over anhydrous Na SO and evaporated in vacuum. A
2
4
further purification process was carried out by silica chromatog-
raphy in a porous disc filter funnel, where the pure 1 decyl azide
was obtained by a flow of hexane (400 mL), whereas the traces of
2.3. Combustion calorimetry
1
starting 1-bromo-decane were trapped in the silica. H NMR
The molar enthalpies of combustion of 1-octyl azide and 1
decyl-azide were measured with an isoperibolic calorimeter with a
static bomb and a stirred water bath. The sample was placed
(under an inert atmosphere in a glove-box) in a polythene ampoule
and burned in oxygen at 3.04 MPa pressure. The detailed procedure
has been described previously [7]. The combustion products were
examined for carbon monoxide (Dräger tube) and unburned
carbon but neither was detected. The energy equivalent of the
(
1
400 MHz, CDCl
.18 (m, 14H), 0.88 (t, J = 6.9 Hz, 3H).
The solid sample of 4-nitrophenyl azide was purified by re-
3
) d 3.25 (t, J = 7.0 Hz, 2H), 1.67–1.52 (m, 2H), 1.43–
crystallization from ethanol and then by fractional sublimation in
vacuum. The liquid samples of 1-octyl azide and 1 decyl azide were
purified by a repeated fractional distillation at reduced pressure.
Purities of samples were determined by a Hewlett Packard gas
chromatograph 5890 Series II equipped with a flame ionization
detector. We used a 25 m capillary column HP-5 with inside
diameter of 0.32 mm and a film thickness of 0.25 mm. The standard
temperature program of the GC was T = 333 K for 180 s followed by
calorimeter
ecalor was determined with a standard reference
sample of benzoic acid (sample SRM 39j, NIST). For the reduction of
the data to standard conditions, conventional procedures [8] were
used. Auxiliary data are collected in Table 4. Correction for nitric
ꢂ1
ꢂ3
a heating rate of 0.167 K s toT = 523 K. No impurities (greater than
acid formation was based on titration with 0.1 mol dm NaOH
mass fraction 0.001) for both samples could be detected in the
samples used for the thermochemical measurements.
Provenance and purity of the compounds prepared for
thermochemical studies in this work are given in Table 1.
Cautions should be taken during the manipulation and storage
of azides. These compounds must be handled in a powerful fume
hood. They should be handled only on a small scale with
appropriate safety precautions (face shields, leather gloves and
protective clothing).
(aq). The residual water concentration in the liquid samples was
determined by Karl Fischer titration before starting experiments
and appropriate corrections have been made for combustion
results.
2.4. Phase transitions in the solid state. DSC-measurements
The thermal behaviour of 4-nitro-phenyl azide including
melting temperature and enthalpy of fusion was determined with
a PerkinElmer DSC-2. The fusion temperature and enthalpies were
determined as the peak onset temperature and by using a straight
baseline for integration, respectively. The temperature and heat
flow rate scale of the DSC was calibrated by measuring high-purity
indium. The thermal behaviour of the specimen was investigated
2.2. Vapour pressure measurements
Vapour pressures of organic azides were determined using the
method of transpiration [5,6] in a saturated nitrogen stream. About
.5 g of the sample was mixed with small glass beads and placed in
ꢂ1
0
during heating the sample at a cooling rate of 10 K min . The DSC
a thermostated U-shaped saturator. A well defined nitrogen stream
was passed through the saturator at a constant temperature
measurements were repeated in triplicate and values agreed
g
ꢂ1
within the experimental uncertainties uð
D
H Þ = 0.2 kJ mol for
cr
m
(ꢃ0.1 K), and the transported material was collected in a cold trap.
the enthalpy of fusion and u(T) = 0.5 K for the melting temperature.
Table 1
Provenance and purity of the synthesis materials.
Material
4-Nitro-phenyl azide
1-Octyl azide
1-Decyl azide
CASRN
1516-60-5
7438-05-3
62103-13-3
Origin
Synthesis in this work
Fractional sublimation
0.999a
Synthesis in this work
Fractional distillation
0.999
Synthesis in this work
Fractional distillation
0.999
Method of purification
GC purity (mass fraction)
Water content after drying
306.42 ppm
266.02 ppm
a
The same result was measured by DSC.

8
0
V.N. Emel`yanenko et al. / Thermochimica Acta 597 (2014) 78–84
Table 2
Calculated enthalpies of azides are based on the electronic energy
calculations obtained by the compound method using standard
procedures of statistical thermodynamics [12].
Results from measurements of the vapour pressure
transpiration method.
p
of azides using the
Ta
mb
(mg)
V
c
Gas-flow
(dm /h)
pd
(Pa)
u(p)
(%)
g
(N2)
Dl Hm or
3
3
(
K)
(dm )
g
cr
D
H
m
ꢂ1
3. Results and discussion
(
kJ mol
)
g
cr
ꢂ1
4
-Nitro-phenyl azide;
D
H
m
(298.15 K) = 93.0 ꢃ 0.6 kJ mol
ꢂ
ꢃ
3.1. Vapour pressure and sublimation/vaporization enthalpies
À
Á
p
Pa
321:63
R
99935:42
RꢅðT;KÞ
23:3
T;K
ln
ꢂ
ꢂ
ln
R
298:15
313.3
21.1
302.9
4.50
4.50
4.50
4.50
4.50
4.50
4.50
4.50
1.20
1.89
3.58
6.02
8.23
11.52
15.99
19.54
0.92
92.64
92.54
92.4
92.28
92.22
92.13
92.06
92.02
Temperature dependence of vapour pressures measured for
azides were fitted with the following equation [12]:
317.4
9.4
9
81
0.76
0.64
0.58
0.56
0.54
0.53
0.53
3
3
3
3
3
3
4
23.3
28.5
31.2
34.9
38.1
39.9
39.4
26.6
29
17.9
12.6
10.4
15.6
13.6
13.3
19.6
ꢀ
ꢁ
b
T
g
1
T
R ꢀ lnp ¼ a þ
þ
D
C
p
ꢀ ln
(2),
i
T
0
15.2
g
g
ꢂ1
-Nitro-phenyl azide;
D
H
m
(298.15 K) = 93.0 ꢃ 0.6 kJ mol
where a and b are adjustable parameters and Dl
C
p
is the difference
1
ꢂ
ꢃ
À
Á
p
Pa
324:89
98385:24
RꢀðT;KÞ
80:2
T;K
ln
¼
ꢂ
ꢂ
ln
of the molar heat capacities of the gaseous and the liquid phase
respectively. T appearing in Eq. (2) is an arbitrarily chosen
reference temperature (which has been chosen to be 298.15 K).
Consequently, vaporization (or sublimation) enthalpy at tempera-
ture T was indirectly derived from the temperature dependence of
vapour pressures using Eq. (3):
R
R
298:15
3
45.1
13.7
7.4
6.5
3.8
3.2
2.6
2.6
4.50
4.50
4.50
4.50
4.50
4.50
28.47
42.36
58.58
82.79
113.38
0.52
0.51
0.51
0.51
0.50
0.50
70.71
70.30
69.90
69.50
69.09
68.68
0
350.2
355.2
360.2
365.3
18.0
14.8
17.7
19.2
25.5
370.5
150.41
g
ꢂ1
1
-Octyl azide; Dl
H
m
(298.15 K) = 58.9 ꢃ 0.3 kJ mol
g
g
ꢂ
ꢃ
À
Á
Dl H ðTÞ ¼ ꢂb þ Dl
C
p
ꢀ T
(3)
p
Pa
330:24
R
89107:94
RꢀðT;KÞ
101:5
R
T;K
298:15
m
ln
ꢂ
1.65
ꢂ
ln
276.2
4.28
3.42
2.56
2.21
1.51
1.29
1.11
0.905
0.628
0.553
0.755
0.369
0.503
0.277
0.503
0.259
0.252
0.277
0.252
0.503
0.503
0.252
3.02
6.25
9.04
11.72
15.48
21.19
27.51
0.58
0.56
0.54
0.53
0.52
0.52
0.52
0.51
0.51
0.51
0.51
0.51
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
61.07
60.71
60.44
60.1
279.8
282.5
285.8
289.4
292.2
293.2
296.2
300.2
302.1
303.1
307
1.92
3.02
3.02
3.02
3.02
1.01
3.02
3.02
1.11
1.01
3.02
1.11
3.02
1.11
3.02
1.11
1.01
1.11
1.01
3.02
3.02
1.01
Eqs. (2) and (3) are also valid for the study of the solid sample. For
this case the enthalpy of sublimation is derived from Eq. (3) by
1.88
2.15
2.02
2.25
2.04
2.13
1.91
2.04
3.12
1.96
3.48
2.39
6.02
3.96
3.82
4.57
4.29
10.36
10.36
5.02
g
g
g
using the appropriate values of
D
C
p
. Values of
D
C
p
and Dl
C
p
59.74
59.45
59.35
59.04
58.64
58.45
58.34
57.94
57.64
57.24
56.84
56.54
56.44
56.24
56.24
56.04
56.04
56.04
cr
cr
have been calculated according to the procedure developed by
l
29.11
Chickos et al. [13] based on isobaric molar heat capacities C and
p
37.07
48.08
58.05
65.04
83.45
108.88
135.49
188.01
240.59
238.5
259.2
268.35
323.7
323.61
cr
p
l
p
C . The C values were estimated by group-contribution method
14]. The experimental value Cp = 164.1 J K mol measured by
cr
ꢂ1
ꢂ1
[
DSC [4] was used for 4-nitro-phenyl azide. Experimental results for
azides and parameters a and b are listed in Table 2.
The compilation of sublimation/vaporization enthalpy meas-
urements on azides from this work and from the literature is
presented in Table 3. Only few experimental studies of azides
3
3
3
10
13.9
17.9
3
3
3
3
3
3
3
1
20.9
21.8
23.9
23.9
25.8
25.8
25.8
relevant to this study were found in the literature [15,16]. We
g
l
treated experimental literature data using
D
C
p
-values listed in
g
g
Table 3 and calculated
D Hm (298.15 K) or Dl Hm (298.15 K) for the
cr
sake of comparison with our results. It has turned out that the
ꢂ1
enthalpy of sublimation of 4-nitro-phenyl azide 81 ꢃ3 kJ mol
313.49
g
ꢂ1
-Decyl azide; Dl
H
m
(298.15 K) = 67.8 ꢃ 0.4 kJ mol
admittedly used until today in the literature was roughly assessed
ꢂ
ꢃ
À
Á
p
Pa
357:51
R
103212:11
RꢀðT;KÞ
118:2
R
T;K
298:15
ln
ꢂ
1.44
ꢂ
ln
by analogy with the enthalpy of sublimation of 1,3-dinitrobenzene
ꢂ1
2
99.1
[4]. Thus, any reasonable explanation of 10 kJ mol
difference
4.481
2.801
1.953
1.159
0.915
0.854
0.793
0.732
0.915
0.225
4.80
4.80
3.66
3.66
3.66
3.66
3.66
3.66
3.66
1.04
4.31
6.66
0.07
0.07
0.06
67.69
67.1
66.5
65.91
65.33
64.72
64.13
63.55
62.94
62.34
3
3
04
09
1.39
1.49
1.3
with our experimental value (see Table 3) was hardly required. In
this work, vapour pressures for 4-nitro-phenyl azide were
measured over the solid as well as over liquid sample. The
10.17
14.89
21.52
33.05
47.44
67.69
91.4
314
ꢂ0.3
318.9
1.48
2.12
2.83
3.73
6.29
2.26
ꢂ0.83
0.04
0.13
g
ꢂ1
enthalpy of vaporization Dl Hm (298.15 K) = 74.5 ꢃ1.1 kJ mol for
3
3
3
3
3
24
29
33.9
39
44.1
4-nitro-phenyl azide measured in this work by transpiration was
g
1.05
significantly different from the value Dl Hm (298.15 K) = 116.9 ꢃ 0.7
ꢂ2.49
ꢂ1
kJ mol measured with the same method earlier [15]. It makes
134.7
4.17
oneself conspicuous that the latter value is even larger than
available enthalpies of sublimation of 4-nitro-phenyl azide (see
Table 3). Consequently, the transpiration result from [15] seems to
be in error.
The molar enthalpy of vaporization of 1-alkyl azides were
measured earlier by very simple static device [16]. Using Eqs. (2)
and (3) we adjusted vaporization enthalpies from this work [16] to
the reference temperature for comparison with our new results: 1-
a
b
c
Saturation temperature (u(T) = 0.1 K).
Mass of transferred sample condensed at T = 243 K.
3
Volume of nitrogen (u(V) = 0.005 dm ) used to transfer m (u(m) = 0.0001 g) of the
sample.
d
Vapour pressure at temperature T, calculated from the m and the residual
vapour pressure at T = 243 K.
g
1
ꢂ1
2
.5. Computational details
octyl azide
D
Hm (298.15 K) = 62.1 kJ mol and of 1 decyl azide
g
ꢂ1
Dl Hm (298.15 K) = 73.4 kJ mol
(see Table 3). These literature
Standard ab initio molecular orbital calculations for azides were
results are significantly higher in comparison to our more reliable
results from transpiration method (see Table 3). In our previous
work [3] we reported that the family of 1-alkyl-azides fit very well
in the linear correlation. The dependence of vaporization enthalpy
performed with the Gaussian 09 series of programs [9]. Energies of
compounds under study were calculated using G4 level [10].
Details on this method have been given in our previous paper [11].

V.N. Emel`yanenko et al. / Thermochimica Acta 597 (2014) 78–84
81
Table 3
Compilation of data on enthalpies of vaporization Dl
g
H
m
(298.15 K) of azides.
1
g
cr
cr
p
)
g
g
cr
g
g
cr
g
Ref
[4]
This work
[15]
This work
[16]
This work
This work
[16]
Compounds
T-range
K)
D
Hm or Dl Hmat Tav
D
Hm or Dl Hmat 298.15 K
C ð
D
C
p
ÞC
ð
Dl
C
p
Þ
p
(
ꢂ1 ꢂ1
(kJ molꢂ1
)
(
J mol
K
4-Nitro-phenyl azide (cr)
4-Nitro-phenyl azide (liq)
1-Octyl azide (l)
164.0
(ꢂ25.3)
267.7
81.0 ꢃ 3.0
93.0 ꢃ 0.6
116.9 ꢃ 0.7
74.5 ꢃ 1.1
62.1
313.3–338.1
92.4
110.5
69.7
363–393
45.1–370.5
350–420
3
(ꢂ80.2)
349.5
53.3
a
(
ꢂ101.5)
58.5
276.2–325.8
58.4
58.2
58.9 ꢃ 0.3
1
-Decyl azide (l)
373–480
413.3
ꢂ118.8)
73.4
a
(
67.9
67.8 ꢃ 0.4
This work
This work
2
99.1–344.1
65.1
a
Calculated using Eq. (4).
on the number of C-atoms N
C
was calculated solely using the
differences meet expectation for contributions from two CH
2
literature data. Having measured two representatives of this series
in this work, we have refined this correlation with the new data:
groups (within the combined experimental uncertainties) and
prove consistency of our new values.
Energy of combustion of 4-nitro-phenyl azide was earlier
determined using an isoperibol static bomb combustion calorim-
eter [4]. The purity of the sample used and the quality of
g
ꢂ1
2
Dl H ð298:15KÞ=ðkJmol Þ ¼ 21:1 þ 4:68 ꢀ N withðR
C
m
¼
0:9997Þ
(4)
experimental results reported in this work were apparently on the
ꢁ
m
high level. The molar enthalpy of formation Df
ꢃ 4.3 kJ mol
H
(cr) = 308.7
We would recommend to use Eq. (4) for thermochemical
calculations of 1-alkyl azides of general formula CH -(CH -N
ꢂ1
(see Table 7) of 4-nitro-phenyl azide [4] was
accepted in this work for the further thermochemical calculation.
3
2
)
n
3
.
3.2. Enthalpies of formation from the combustion calorimetry
3
.3. Enthalpy of fusion of 4-nitro-phenyl azide
Results of combustion experiments on 1-octyl azide and 1
As per the rule, prior to the vapour pressure measurements, the
decyl-azide are summarized in Tables 4–6. Values of the standard
ꢁ
crystalline samples have to be studied by DSC. Information about
possible phase transitions in the sample under study helps
choosing of the temperature range for investigation and guide
vapour pressure measurements within the range where the
specific energy of combustion,
D
c
u , the standard molar enthalpy
ꢁ
of combustion, DcH , and the standard molar enthalpy of
m
ꢁ
formation in the liquid state Df
H
(l) was based on the reactions:
m
C
8
17
H N
3
+ 12.25O
2
= 8CO
2
+ 8.5H
2
O + 1.5N
2
(5)
(5)
compound of interest exists in only
a certain crystalline
modification. The melting temperature, purity (0.999 mass
fraction), and enthalpy of fusion of 4-nitro-phenyl azide were
measured in the present work by DSC. No phase transitions other
than melting of 4-nitro-phenyl azide have been detected. The
onset, peak and end temperatures of the DSC run were as follows:
C
10
H
21
N
3
+ 15.25O
2
= 10CO
2
+ 10.5H
2
O + 1.5N
2
(6)
(6)
ꢁ
m
3
3
41.4 K, 342.5 K and 344.4 K. For comparison, the melting point of
45 K was reported in Ref. [4], but it is not quite clear which
Values of the molar enthalpy of formation, Df
azides were calculated from the enthalpy balance for Reactions (5)
and (6) according to the Hess’s Law using molar enthalpies of
2 2
formation of H O (l) and CO (g) as assigned by CODATA [17]. The
uncertainties of the standard molar energy and enthalpy of
combustion correspond to expanded uncertainties of the mean
H
(l) of 1-alkyl
method was used for this measurement. In any case, the end
temperature of the melting peak in our work was in agreement
with those from [4]. Moreover, the purity of our sample of 0.999
mass fraction, was confirmed by the GC method. The experimental
(
0.95 level of confidence) and include the contribution from the
calibration with benzoic acid and from the values of the auxiliary
ꢁ
Table 4
Formula, density
coefficients ( V/
quantities used. Enthalpy of combustion and the Df
H
(l) = 96.7
m
r
(T = 293 K), massic heat capacity c
p
(T = 298.15 K), and expansion
ꢂ1
ꢃ 3.0 kJ mol of 1-octyl azide was earlier published in the U.S.
d
p
dT) of the materials used in the present study.
ꢁ
m
Naval Powder Factory report [18]. Our new Df
H
(l)-value is of
Formulaa
r
C
(J K
10 ꢀ (
ꢂ6
d
)
V/
d
T)
b
ꢂ1
Compounds
p
p
17 kJ mol less positive. Study of scarce details in this report has
ꢂ3
ꢂ1 ꢂ1
3
ꢂ1
(
g cm
)
g
)
(dm K
not revealed any explanation. Analysis of the experimental data for
-alkyl-azide (alkyl = pentyl, hexyl, heptyl and octyl) reported by
1
1
-Octyl azide
-Decyl azide
C
8
H
H
17
21
CH1.93
N
N
3
0.84c
2.25d
1.0
1.0
0.1
0.1
1
C
10
3
0.87c
2.26d
Murrin et al. [18] have revealed the general inconsistency of the
enthalpies for this series. For example the enthalpies of formation
e
Polyethylene
0.92 [7]
1.50 [7]
2.53 [7]
1.67 [7]
Cottonf
CH1.774O0.887
ꢁ
m
ꢂ1
Df
H
(l) = 151 kJ mol were identical for 1-pentyl azide and 1-
a
The relative atomic masses used for the elements C, H, N and O were calculated
as the mean of the bounds of the interval of the standard atomic weights
recommended by the IUPAC commission in 2011 [27] for each of these elements.
hexyl azide. Such an anomalous behaviour has never been
ꢁ
m
observed for any homologous family [23], because Df
H
(l)-
b
values of 1-pentyl azide and 1-hexyl azide are expected to be
Estimated [8].
ꢂ1
c
Measured with a calibrated pycnometer with uncertainties u(T) = 0.1 K and u
different by at least ꢂ28.85 kJ mol (contribution for CH
2
group)
ꢂ3
(
r) = 0.01 g cm
d
.
[
23]. In contrast, our new enthalpies of formation of 1-octyl azide
ꢁ
ꢁ
Calculated by group-contribution method [13].
Energy of combustion Dc
Energy of combustion Dc
ꢂ1
Df
H
(l) = 80.6 ꢃ 2.2 kJ mol
and 1 decyl-azide Df
(see Table 7) differ by 51.6 kJ mol
H
(l) = 29.0
e
ꢁ
ꢁ
ꢂ1
ꢁ
ꢂ1
m
m
u
u
(polyethylene) = ꢂ46357.3 J g ; u(Dcu ) = 3.6 J g
.
ꢂ1
ꢂ1
f
ꢂ1
ꢁ
ꢂ1
ꢃ 3.0 kJ mol
.
These
(cotton) = ꢂ16945.2 J g ; u(
D u ) = 4.2 J g .
c

8
2
V.N. Emel`yanenko et al. / Thermochimica Acta 597 (2014) 78–84
Table 5
ꢁ
a
Results for combustion experiments at T = 298.15 K (p = 0.1 MPa) of the 1-octyl azide.
m(substance)/g
0.323745
0.001169
0.279711
1.66819
0.323617
0.001107
0.342548
1.86402
0.389136
0.001221
0.280926
1.83278
0.176607
0.001423
0.392715
1.6596
0.268154
0.001178
0.338976
1.71677
0
m (cotton)/g
00
m
(polyethene)/g
c
DT /K
(
e
calor) ꢀ (ꢂ
D
T
c
)/J
)/J
/J
ꢂ24817.5
ꢂ27730.8
ꢂ27266
ꢂ24689.7
ꢂ25540.2
(
D
e
cont) ꢀ (ꢂ
DT
c
ꢂ27.07
69.88
ꢂ31.07
76.45
ꢂ30.29
ꢂ27.15
51.96
ꢂ28.13
62.71
U
U
decomp HNO
corr/J
3
74.06
7.54
20.69
D
6.75
19.81
12966.65
ꢂ36391.3
7.8
18.76
15879.6
ꢂ36398.7
7.09
24.11
18205.21
ꢂ36399.6
7.25
19.96
15714.01
ꢂ36413.3
0
0
ꢂm ꢀ
D
D
c
u /J
00
00
ꢂm
ꢀ
c
u /J
13022.97
ꢂ36416.7
36403.7
ꢁ
ꢂ1
D
c
u (liq)/(J g
)
ꢁ
ꢁ
ꢂ1
ꢂ
D
c
u (liq)/(J g
)
ꢂ1
b
u(
D
c
u )/J g
4.8
a
0
3
The definition of the symbols assigned according to Ref [8] is as follows: m (substance) and m (cotton) are, respectively, the mass of compound burnt and the mass of
i
fuse (cotton) used in each experiment, masses were corrected for buoyancy; V (bomb) = 0.2511 dm is the internal volume of the calorimetric bomb; p (gas) = 3.00 MPa is the
initial oxygen pressure in the bomb; m (H
equivalent of the calorimeter;
exchange during the experiment;
i
ꢂ1
2
i
O) = 10.00 g is the mass of water added to the bomb for dissolution of combustion gases;
corr is the corrected temperature rise from initial temperature T to final temperature T , with the correction
cont is the energy equivalents of the bomb contents in their initial
e
calor = (14876.9 ꢃ 1.0) J K is the energy
f
i
f
D
T
c
= T ꢂ T +
D
T
D
T
corr for heat
i
f
e
e
e
3
cont and final states
e
cont, the contribution for the bomb content is
corr is the
i
i
f
f
calculated with (
econt) ꢀ (ꢂDT
c
) = (
cont) ꢀ (T ꢂ 298.15) + (
e
cont) ꢀ (298.15 ꢂ T +
D
Tcorr).
D
U
decomp HNO
is the energy correction for the nitric acid formation. DU
correction to standard states.
b
Uncertainties in this table are expressed as the standard deviation of the mean.
1
cr
ꢂ1
molar enthalpy of fusion
D
H
m
= 21.3 ꢃ 0.5 kJ mol measured in
additional argument to support the reliability of our new result
is required. A valuable test of consistency of the experimental data
on the phase change sequence sublimation–melting–vaporization
provides a simple calculation according to Eq. (8):
1
cr
ꢂ1
this work is significantly higher than
45 K measured by DSC in [4]. The reason for this disagreement is
difficult to identify because of absence of the necessary details in
4]. Probably it could be insufficient peak integration in the earlier
DSC software. Generally, the experimental molar enthalpy of
D
H
m
= 17.1 ꢃ0.3 kJ mol at
3
[
1
g
g
1
D
H
m
ð298:15KÞ ¼
D
H
m
ð298:15KÞ ꢂ
D
H
m
ð298:15KÞ
(8)
cr
cr
1
fusion
cr
m
D H is referred to the melting temperature Tfus. The
measured enthalpy of fusion have to be adjusted to the reference
temperature T = 298.15 K. The adjustment was calculated from the
equation [19]:
Indeed, in this work the sample of 4-nitro-phenyl azide was
deliberately investigated by the transpiration method in both
g
ranges, above and below the Tfus = 341.4 K. The value of
D Hm
cr
ꢂ1
1
cr
1
ð298:15KÞg=ðJmolꢂ1Þ
(298.15 K) = 93.0 ꢃ 0.6 kJ mol was obtained in this work over the
fD
H
m
ðT =KÞ ꢂ
D
H
m
fus
cr
cr
solid sample in the temperature range 313.3–338.2 K and the
¼
fð0:75 þ 0:15C Þ½ðT =KÞ ꢂ 298Kꢆg
g
p
fus
vaporization enthalpy for 4-nitro-phenyl azide
Dl Hm
1
p
ꢂ fð10:58 þ 0:26C Þ½ðT =KÞ ꢂ 298:15Kꢆg
(7)
ꢂ1
fus
(
298.15 K) = 74.5 ꢃ1.1 kJ mol from measurements over the liquid
sample in the temperature range 345.1–370.5 K. The molar
enthalpy of fusion calculated according to Eq. (7) as the difference:
With this adjustment (the uncertainty of the correlation was
1
g
g
ꢂ1
1
D
H
m
(298.15 K) =
D
Hm
ꢂ
Dl Hm = 18.5 ꢃ1.3 kJ mol was in good
not taken into account), the molar enthalpies of fusion,
298.15 K) = 18.9 ꢃ 0.5 kJ mol , was calculated and used to estab-
D
H
m
cr
cr
cr
ꢂ1
ꢂ1
agreement with (298.15 K) = 18.9 ꢃ 0.5 kJ mol , directly measured
in this work by DSC and adjusted to T = 298.15 K. Thus, our new
results for sublimation, fusion and vaporization enthalpies for 4-
nitro-phenyl azide have been proven to be consistent.
(
lish consistency of the thermochemical data set for 4-nitro-phenyl
azide as it described below.
3
.4. Consistency test of the vaporization, sublimation and fusion
3
.5. Gas phase enthalpies of formation of azides
enthalpies of 4-nitro-phenyl azide
Experimental values of sublimation and vaporization enthal-
pies of azides from Tables 2 and 3 can now be used together with
Since a significant discrepancy between available fusions
enthalpies of 4-nitro-phenyl azide have been observed, the
Table 6
ꢁ
a
Results for combustion experiments at T = 298.15 K (p = 0.1 MPa) of the 1-decyl azide.
m (substance)/g
0.192052
0.001314
0.321215
1.50253
0.263736
0.001404
0.312549
1.6596
0.219859
0.001232
0.342801
1.64137
0.290458
0.000995
0.292872
1.66665
0.356894
0.001177
0.297984
1.85263
0
m (cotton)/g
00
m
(polyethene)/g
c
DT /K
(
e
calor)ꢀ(ꢂ
D
T
c
)/J
)/J
ꢂ22237.1
ꢂ24561.7
ꢂ24291.9
ꢂ24666
ꢂ27418.6
(
D
e
cont)ꢀ(ꢂ
DT
c
ꢂ24.17
54.35
ꢂ27.04
59.73
ꢂ26.77
57.93
ꢂ27.17
ꢂ30.64
68.09
U
U
decompHNO
corr/J
3
/J
63.91
6.75
16.86
D
6.11
22.27
14890.66
ꢂ37947.7
6.79
23.79
14488.93
ꢂ37952.6
6.78
20.88
7.62
19.94
13813.73
ꢂ37937.9
0
0
ꢂm ꢀ
D
D
c
u /J
00
00
ꢂm ꢀ
c
u /J
15891.33
ꢂ37941.2
13576.76
ꢂ37970.8
ꢁ
ꢂ1
D
c
u (liq)/(J g
)
ꢁ
ꢁ
ꢂ1
b
ꢂ
D
c
u (liq)/(J g
u )/J g
)
37950.0
ꢂ1
c
u(
D
c
5.8
a
The definition of the symbols assigned is identical to those in Table 5.
b
c
ꢂ1
The energy equivalent of the calorimeter
ecalor = (14799.8 ꢃ 1.0) J K
.
Uncertainties in this table are expressed as the standard deviation of the mean.

V.N. Emel`yanenko et al. / Thermochimica Acta 597 (2014) 78–84
83
Table 7
Thermochemical data at T = 298.15 K (p = 0.1 MPa) for azides (in kJ mol ).a
ꢁ
ꢂ1
ꢁ
m
ꢁ
m
ꢁ
m
ꢁ
m
ꢁ
m
ꢁ
m
Compounds
Dc
H
(liq or cr)
Df
H
(liq or cr)
Dcr
H
or D1
H
Df
H
(g) Exp.
Df
H
(g)
c
4
-Nitro-phenyl azide (cr)
ꢂ3241.4 ꢃ 4.2 [4]
308.7 ꢃ 4.3 [4]
93.0 ꢃ 0.6
401.7 ꢃ 4.3
396.6 ꢃ 4.0
b
7
4.5 ꢃ 1.1
1
1
-Octyl azide (liq)
-Decyl azide (liq)
ꢂ5658.2 ꢃ 2.0
ꢂ6965.3 ꢃ 2.6
80.6 ꢃ 2.2
29.0 ꢃ 3.0
58.9 ꢃ 0.3
139.5 ꢃ 2.2
96.8 ꢃ 3.0
137.7 ꢃ 4.0
94.8 ꢃ 4.0
67.8 ꢃ 0.4
a
b
c
Uncertainties correspond to expanded uncertainties of the mean (0.95 level of confidence).
Enthalpy of vaporization from Table 3.
ꢂ1
The original G4 value 384.6 kJ mol obtained from the atomisation procedure was corrected according to the empirical correlation from [25] (see text).
the results from combustion experiments (see Tables 5 and 6) for
further calculation of the gas standard enthalpies of formation,
For this purpose the well balanced distribution reaction:
ꢁ
ꢁ
Phenylazide þ nitro ꢂ benzene
Df
H
(g) at 298.15 K. The resulting experimental values of Df
H
(g)
m
m
¼
xꢂnitro ꢂ phenylazide þ benzene
(9)
for 4-nitro-phenyl azide and 1-alkyl azides are given in Table 7
column 5) and they could be now compared with the theoretical
(
results from quantum chemical calculations.
was applied. Enthalpies H298 of all reaction participants were
We have calculated using the G4 method total energies E
T = 0 K and enthalpies H298 at T = 298.15 K (see Table 8). In this work
0
at
calculated in this work by G4 method (Table 9). Enthalpy of this
ꢁ
distribution reaction,
D
r
H , was calculated according to the Hess’s
for the distribution Reaction (9) expresses
m
ꢁ
we used the atomization procedure (AT) for calculation the
Law. The value of Dr
H
m
ꢁ
m
theoretical values Df
H
(g, G4) for 4-nitro-phenyl azide and 1-
energetic of the mutual interaction of substituents on the benzene
ring depending on their ortho-, meta- or para-position. A significant
advantage of the quantum-chemical calculations towards benzene
derivatives is that this method allows estimation of substituent
alkyl azides. These values are given in Table 7 (column 6). Enthalpy
of formation for 4-nitro-phenyl azide was calculated according to
the procedure developed for nitro-compounds and described in
our previous paper [25]. The linear correlation between experi-
effects directly from enthalpies H
98
skipping the common step of
2
ꢁ
ꢁ
mental and G4 calculated enthalpies of formation Df
H
(exp)/in
the calculation of Df H (g) for the Reaction (9) participants by any
m
m
ꢁ
ꢂ1
kJ mol = 1.0083 Df
H
(G4) + 8.8 with (r = 0.9993). With this linear
theoretical or empirical method [20,21].
m
ꢂ1
correlation and the G4 value 384.6 kJ mol obtained from the
Substituent effects in nitro-phenyl azide isomers defined by
ꢁ
m
atomization
procedure
the
current
result
Dr
H
of Reaction (9) are listed in Table 9. It is apparent that all
ꢂ1
1.0083 ꢀ 384.6 + 8.8 = 396.6 kJ mol
was calculated. The latter
three isomers are significantly destabilized. Destabilizations of the
meta- and para-isomers are approximately on the same level of
ꢁ
m
ꢂ1
value is in a good agreement with Df
H
(G4) = 393.9 kJ mol
ꢂ1
derived in [2] by using different isodesmic reactions. Results
calculated by using G4 for 4-nitro-phenyl azide and 1-alkyl azides
are in very close agreement with the experiment within the
combined uncertainties. Thus, the composite G4 method can be
further recommended for calculations of the azide family. At the
same time, such are good agreement could serve as an evidence of
consistency of thermochemical results measured in this work by
different techniques.
about 2–4 kJ mol . The nitro- and azide-groups for meta- and
para-isomers are in plane with the benzene ring (Fig.1). In contrast,
the nitro-group is out of plain in 2-nitro-phenyl azide and this
steric interaction caused the profound destabilization of the ortho-
ꢂ1
isomer of 29.6 kJ mol (see Table 9).
It is interesting to compare the size of substituent effects in
nitro-phenyl azides with those in similar benzene derivatives
nitro-benzonitriles, where reliable experimental data are available
[
22]. Using archival experimental enthalpies of formation for
3.6. Pairwise interactions of substituents in nitro-phenyl azides
gaseous benzene and its cyano and nitro derivatives [23–26], we
calculated values of
ꢁ
D
r
H
according to the reaction:
m
Mutual interactions of substituents on the benzene ring belong
Benzonitrile þ nitro ꢂ benzene
to the basics of organic chemistry. Energetics of interplay of
electron-donating and electron-accepting substituents in the
ortho-, meta- and para-position on the ring determine the
mechanism of a chemical reaction. Having established a set of
G4 enthalpies H298 for nitro-phenyl azide isomers (see Table 8) we
are able now to calculate effects of mutual interactions of nitro-
group with the azide-group on the benzene ring in the ortho-,
meta- and para-position.
¼
xꢂnitro ꢂ benzonitrile þ benzene
(10)
Results for interactions of the nitro- and cyano-groups are given
in Table 9 and we can conclude that the meta- and para-nitro-
Table 9
ꢁ
Mutual interactions of substituents,
D
r
H
, on the benzene ring for nitro-phenyl
In our recent work [20,21] we suggested to derive the
m
azides and the analogous nitro-benzonitriles as calculated by G4 (at 298.15 K,
interactions on the benzene ring directly from enthalpies H298
.
ꢂ1
in kJ mol ).
ꢁ
D
r
H
Compounds
m
Table 8
G4 total energies at 0 K, enthalpies at 298.15 K and standard enthalpy of formation
ꢁ
m
D
f
H
(g) at 298.15 K of the nitro-phenyl azides and parent compounds.
29.6a
2-Nitro-phenyl azide
3-Nitro-phenyl azide
a
ꢁ
m
4.9
Compounds
E
0
H
298
Df
H
G4
a
4
2
-Nitro-phenyl azide
-Nitro-benzonitrile
2.1
ꢂ1
(
Hartree)
(Hartree)
(kJ mol
)
b
b
b
19.5 ꢃ 3.9
10.6 ꢃ 4.0
14.4 ꢃ 4.4
2
3
4
-Nitro-phenyl azide
-Nitro-phenyl azide
-Nitro-phenyl azide
Phenyl azide
Nitro-benzene
Benzene
ꢂ600.090788
ꢂ600.100265
ꢂ600.101321
ꢂ395.644363
ꢂ436.551642
ꢂ232.093987
ꢂ600.080359
ꢂ600.089780
ꢂ600.090835
ꢂ395.636364
ꢂ436.543854
ꢂ232.088586
396.7
399.7
424.4
–
3-Nitro-benzonitrile
4-Nitro-benzonitrile
a
Calculated using the G4 energies from Table
7 for the reaction: phenyl
azide + nitro-benzene = x-nitro-phenyl azide + benzene.
–
b
Calculated using the experimental data [22–26] for the reaction: benzonitrile +
nitro-benzene = x-nitro-benzonitrile + benzene.
–

8
4
V.N. Emel`yanenko et al. / Thermochimica Acta 597 (2014) 78–84
Fig. 1. Optimized with the G4 structures of the nitro-phenyl azides.
benzonitrile are also destabilized by 10.6 ꢃ 4.0 and 14.4 ꢃ 4.4 kJ
Heyd, E. Brothers, K.N. Kudin, V.N. Staroverov, T. Keith, R. Kobayashi, J.
Normand, K. Raghavachari, A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi, M.
Cossi, N. Rega, J.M. Millam, M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo, J.
Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C.
Pomelli, J.W. Ochterski, R.L. Martin, K. Morokuma, V.G. Zakrzewski, G.A. Voth,
P. Salvador, J.J. Dannenberg, S. Dapprich, A.D. Daniels, O. Farkas, J.B. Foresman,
J.V. Ortiz, J. Cioslowski, D.J. Fox, Gaussian 09, Revision C .01, Gaussian, Inc.,
Wallingford CT, 2010.
ꢂ1
mol respectively. This level of destabilization is stronger than
those for nitro-phenyl azides. Cyano is a quite small in comparison
to the azide group. Consequently, the destabilization due to both
steric and electronic interactions in ortho-nitro-benzonitrile of
ꢂ1
1
9.5 ꢃ 3.9 kJ mol as expected lower in comparison to 2-nitro-
phenyl azide. Thus, the mutual substituent effects for nitro-phenyl
azide derived in this work seem to be reasonable in size.
[10] L.A. Curtiss, P.C. Redfern, K. Raghavachari, Gaussian-4 theory, J. Chem. Phys.126
(
2007) 0841081–08410812.
[
11] S.P. Verevkin, V.N. Emel’yanenko, R. Notario, M.V. Roux, J.S. Chickos, J.F.
Liebman, Rediscovering the wheel thermochemical analysis of energetics of
the aromatic diazines, J. Phys. Chem. Lett. 3 (2012) 3454–3459.
4. Conclusion
[
12] D.A. McQuarrie, Statistical Mechanics, Harper and Row, New York, 1976.
[
13] J.S. Chickos, S. Hosseini, D.G. Hesse, J.F. Liebman, Heat capacity corrections to a
standard state: a comparison of new and some literature methods for organic
liquids and solids, Struct. Chem. 4 (1993) 271–278.
Complex of thermochemical studies leading to the molar
enthalpy of formation of three organic azides was accomplished.
The G4 theoretical gaseous enthalpies of formation of the title
compounds were in agreement with the experiment within the
combined uncertainties. The composite G4 method combined with
the atomization procedure was shown to be suitable for calculation
of enthalpies of formation of the azide family.
[14] J.S. Chickos, W.E. Acree, Enthalpies of sublimation of organic and
organometallic compounds 1910–2001, J. Phys. Chem. Ref. Data 31 (2002)
5
37–698.
[
15] T. Shimizu, S. Ohkubo, M. Kimura, I. Tabata, T. Hori, The vapour pressures and
heats of sublimation of model disperse dyes, J. Soc. Dyers Colour. 103 (1987)
132–137.
[
16] A. Lee, C.K. Law, A. Makino, Aerothermochemical studies of energetic liquid
materials: 3: approximate determination of some thermophysical and
thermochemical properties of organic azides, Combust. Flame 78 (1989)
Acknowledgement
2
63–274.
[
17] J.D. Cox, D.D. Wagman, V.A. Medvedev, CODATA Key Values for Thermody-
This work has been partly supported by the Russian Govern-
ment Program of Competitive Growth of Kazan Federal University.
namics, Hemisphere, New York, 1989.
[18] J.W. Murrin, G.A. Carpenter,1957. The heats of combustion of 1-azidooctane,1-
azidoheptane, 1-azidohexane, and 1-azidopentane U.S. Naval Powder Factory
Research and Development Department, 1–9.
References
[
19] J.S. Chickos, P. Webb, C. Nichols, T. Kiyobayashi, P.-C. Cheng, L. Scott, The
enthalpy of vaporization and sublimation of corannulene coronene, and
perylene at T = 298.15 K, J. Chem. Thermodyn. 34 (2002) 1195–1200.
[
1] S. Brase, K. Banert (Eds.), Organic Azides: Syntheses and Applications, John
Wiley and Sons, Chichester, UK, 2009.
[
20] V.N. Emel’yanenko, S.P. Verevkin, Enthalpies of formation and substituent
effects of ortho-, meta-, and para-aminotoluenes from thermochemical
measurements and from ab initio calculations, J. Phys. Chem. A 109 (2005)
3960–3966.
[
2] O.V. Dorofeeva, O.N. Ryzhova, M.A. Suntsova, Accurate prediction of enthalpies
of formation of organic azides by combining G4 theory calculations with an
isodesmic reaction scheme, J. Phys. Chem. A 117 (2013) 6835–6845.
3] S.P.Verevkin,V.N.Emel’yanenko,M.Algarra,J.ManuelLópez-Romero,F. Aguiar,J.
EnriqueRodriguez-Borges,J.C.G.EstevesdaSilva,Vaporpressuresandenthalpies
of vaporization of azides, J. Chem. Thermodyn. 43 (2011) 1652–1659.
4] A. Finch, P.J. Gardner, A.J. Head, W. Xiaoping, The enthalpy of formation of 4-
nitrophenyl azide, Thermochim. Acta 298 (1997) 191–194.
[
[21] V.N. Emel’yanenko, A. Strutynska, S.P. Verevkin, Enthalpies of formation and
strain of chlorobenzoic acids from thermochemical measurements and from
ab initio calculations, J. Phys. Chem. A 109 (2005) 4375–4380.
[
[
[
22] M.V. Roux, P. Jiménez, J.Z. Dávalos, M. Temprado, J.F. Liebman, Destabilization
in the isomeric nitrobenzonitriles: an experimental thermochemical study, J.
Chem. Thermodyn. 35 (2003) 803–811.
5] D. Kulikov, S.P. Verevkin, A. Heintz, Enthalpies of vaporization of a series of
aliphatic alcohols – experimental results and values predicted by the ERAS-
model, Fluid Phase Equilib. 192 (2001) 187–207.
[
23] S.P. Verevkin, V.N. Emel’yanenko, V. Diky, C.D. Muzny, R.D. Chirico, M. Frenkel,
New group-contribution approach to thermochemical properties of organic
compounds: hydrocarbons and oxygen-containing compounds, J. Phys. Chem.
Ref. Data 42 (2013) 0331021–03310233.
[
6] S.P. Verevkin, Pure component phase changes liquid and gas, in: R.D. Weir, Th.
W. De Loos (Eds.), Experimental Thermodynamics: Measurement of the
thermodynamic properties of multiple phases, vol. 7, Elsevier, 2005, pp. 6–30
[
24] W.V. Steele, R.D. Chirico, I.A. Hossenlopp, S.E. Knipmeyer, A. Nguyen, N.K.
Smith, Determination of ideal-gas enthalpies of formation for key compounds.
The 1990 project results, DIPPR Data Series 2 (1994) 188–215.
(
Chapter 1).
[
7] V.N. Emel’yanenko, S.P. Verevkin, A. Heintz, The gaseous enthalpy of formation
of the ionic liquid 1-butyl-3-methyl-imidazolium dicyanamide from combus-
tion calorimetry vapor pressure mesurements, and ab initio calculations, J.
Amer. Chem. Soc. 129 (2007) 3930–3937.
[
25] S.P. Verevkin, V.N. Emel’yanenko, V. Diky, O.V. Dorofeeva, Enthalpies of
formation of nitromethane and nitrobenzene: new experiments vs quantum
chemical calculations, J. Chem. Thermodyn. 73 (2014) 163–170.
[
8] W.N. Hubbard, D.W. Scott, G. Waddington, in: F.D. Rossini (Ed.), In
Experimental Thermochemistry, Interscience Publishers, New York, 1956,
pp. 75–127.
[26] J.P. Pedley, R.D. Naylor, S.P. Kirby, Thermochemical Data of Organic
Compounds, 2nd ed., Chapman and Hall, London, 1986.
[
27] M.E. Wieser, N. Holden, T.B. Coplen, J.K. Böhlke, M. Berglund, W.A. Brand, P. De
Bièvre, M. Gröning, R.D. Loss, J. Meija, T. Hirata, T. Prohaska, R. Schoenberg, G.
O’Connor, T. Walczyk, S. Yoneda, X.-K. Zhu, Pure Appl. Chem. 85 (2013)
1047–1078.
[
9] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,
G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato,
X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M. Hada,
K. Ehara, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, T. Vreven, J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro, M. Bearpark, J.J.