Thermodynamics of 2-(1′-hydroxycyclohexyl)cyclohexanone: Vaporization, sublimation, and the ideal gas state thermodynamic properties

Article abstract of DOI:10.1021/je0602768

The thermodynamics of one of the byproducts of caprolactam production, 2-(1′-hydroxycyclohexyl)cyclohexanone (ketol), have been studied in this work. Saturated vapor pressure for liquid and crystalline ketol was measured by the Knudsen method in the temperature ranges from (308.2 to 330.4) K and from (289.6 to 300.8) K, respectively. Additionally, the saturated vapor pressures over ketol in the undercooled state and in the liquid were measured by the transpiration method in the temperature range from (287.9 to 303.0) K and from (308.0 to 351.5) K, respectively. The enthalpy of vaporization and the enthalpy of sublimation of ketol at the average temperatures studied were obtained indirectly from the temperature dependence of the vapor pressure measured by the Knudsen method as well as by the transpiration method. Furthermore, the standard molar enthalpy of sublimation was measured directly at 303.1 K using calorimetry. The entropy of ketol in the vapor state at (320.8 and 298.2) K was derived. The thermodynamic properties for 2-(1′-hydroxycyclohexyl) cyclohexanone in the ideal gas state were calculated from statistical mechanic calculations in the broad temperature range from (50 to 1000) K. The gaseous thermodynamic equilibrium constant K° (at 332.1 K) for cyclohexanone auto-condensation (side reaction of the caprolactam production) leading to 2-(1′-hydroxycyclohexyl)cyclohexanone was assessed.

Full text of DOI:10.1021/je0602768

1
946
J. Chem. Eng. Data 2006, 51, 1946-1952
Thermodynamics of 2-(1′-Hydroxycyclohexyl)cyclohexanone: Vaporization,
Sublimation, and the Ideal Gas State Thermodynamic Properties
Marina P. Shevelyova, Dzmitry H. Zaitsau, Yauheni U. Paulechka, and Gennady J. Kabo*
Chemistry Faculty, Belarusian State University, Leningradskaya 14, Minsk 220030, Belarus
Sergey P. Verevkin*
Department of Physical Chemistry, University of Rostock, Hermannstrasse 14, 18051 Rostock, Germany
The thermodynamics of one of the byproducts of caprolactam production, 2-(1′-hydroxycyclohexyl)cyclohexanone
(ketol), have been studied in this work. Saturated vapor pressure for liquid and crystalline ketol was measured by
the Knudsen method in the temperature ranges from (308.2 to 330.4) K and from (289.6 to 300.8) K, respectively.
Additionally, the saturated vapor pressures over ketol in the undercooled state and in the liquid were measured
by the transpiration method in the temperature range from (287.9 to 303.0) K and from (308.0 to 351.5) K,
respectively. The enthalpy of vaporization and the enthalpy of sublimation of ketol at the average temperatures
studied were obtained indirectly from the temperature dependence of the vapor pressure measured by the Knudsen
method as well as by the transpiration method. Furthermore, the standard molar enthalpy of sublimation was
measured directly at 303.1 K using calorimetry. The entropy of ketol in the vapor state at (320.8 and 298.2) K
was derived. The thermodynamic properties for 2-(1′-hydroxycyclohexyl)cyclohexanone in the ideal gas state
were calculated from statistical mechanic calculations in the broad temperature range from (50 to 1000) K. The
gaseous thermodynamic equilibrium constant K° (at 332.1 K) for cyclohexanone auto-condensation (side reaction
of the caprolactam production) leading to 2-(1′-hydroxycyclohexyl)cyclohexanone was assessed.
Introduction
p ) 0.3 kPa. The mole fraction purity of the ketol used in
experiments was 0.9982 according to the fractional melting
Auto-condensation of cyclohexanone leading to the formation
2
analysis.
of 2-(1′-hydroxycyclohexyl)cyclohexanone (ketol) according to
1
Vapor Pressure Measurements, Knudsen Method. The
procedure of measurements has been described in detail.3
Uncertainty in vapor pressure was estimated to be 5 %. The
improved Knudsen cell with enlarged contact surface was used4
for the measurements of the solid sample. Two membranes with
the following parameters were used for the measurements: the
reaction I
-
3
first one with thickness l ) (50 ( 2)‚10 mm and the average
effusion orifice diameter d ) (0.8370 ( 0.0005) mm, and the
is one of the first side reactions at the initial stage of caprolactam
production. Furthermore, auto-condensation of ketones is an
important reaction for the synthesis of bicyclic ketones, alcohols,
and phenylphenols. Thermodynamic properties of ketol in the
condensed state and equilibrium study of reaction involving this
-
3
second one with l ) (84 ( 2)‚10 mm and d ) (0.4467 (
.0005) mm. Mass loss in each experiment was from (4 to 12)
0
mg. The vapor pressures were calculated using the following
3
equation :
2
compound have been reported recently. In this paper, results
1
R
Sorif
derived from vapor pressure measurements of the ketol together
with the direct calorimetric determination of the vaporization
enthalpy of the ketol as well as calculation of the thermodynamic
properties of the ketol in the ideal gas state are reported.
psat ) p* +
k
p*
(1)
(
)
Ssamp
where psat is the equilibrium vapor pressure of the substance;
Ssamp is the geometric surface of the sample; Sorif is the area of
the effusion orifice; k is the transmission probability coefficient
through the effusion orifice; R is the condensation coefficient;
p* is the vapor pressure in the cell calculated as
Experimental Section
Sample. The sample of 2-(1′-hydroxycyclohexyl)cyclohex-
anone was prepared by cyclohexanone dimerization with a water
solution of KOH as catalyst according to the procedure described
in ref 1. The compound was purified by re-crystallization from
petroleum ether and finally distilled at T ) (313 to 318) K and
∆m
kSorif
2πRT
p* )
(2)
τ
x
M
∆
m is the mass loss of the sample during the exposure time τ;
*
Corresponding authors. Contact G.J.K. for results from the Knudsen
T is the temperature of the heat carrier in the thermostat; and
M is the molar mass of the substance (assumption that the vapor
of ketol tends to be monomolecular has been made according
method and calorimetric calculations (e-mail: kabo@bsu.by). Contact S.P.V.
for results from the transpiration method (e-mail: sergey.verevkin@
uni-rostock.de).
1
0.1021/je0602768 CCC: $30.25 © 2006 American Chemical Society
Published on Web 08/30/2006

Journal of Chemical and Engineering Data, Vol. 51, No. 5, 2006 1947
to arguments given in the discussion below). The k coefficient
was determined according to Wahlbeck’s theory as described
Table 1. Saturated Vapor Pressure over the Liquid and the
Crystalline Ketol Determined by the Knudsen Method
3
in refs 4 and 5. An effective diameter of ketol molecule σ )
Ta
∆mb
tc
p f
-
10
7
.214‚10
m was calculated from a van der Waals volume
kd
Kne
K
mg
s
Pa
assuming the molecule to be spherical. The van der Waals
volume was estimated by the geometric parameters of ketol
obtained from quantum-mechanical calculations and the known
g
Liquid d ) (0.4467 ( 0.0004) mm
3
08.22
9.87
9.24
16200
10800
10800
5400
0.8451
0.8609
0.8829
0.9093
0.9252
0.9394
0.9585
3.34
2.45
1.66
1.16
0.97
0.81
0.67
1.23
1.71
2.56
3.73
4.47
5.42
6.64
313.05
317.95
6
-3
atomic radii. The condensation coefficient R ) 5‚10 for the
14.08
10.48
8.47
10.43
12.94
3
3
3
3
22.97
25.33
27.45
30.40
crystalline state was determined from eq 1 taking into account
3600
3611
3600
2
that in the triple point Ttr ) 306.75 K, psat,liq(Ttr) ) psat,cr(Ttr)
and R ) 1 for the liquid state.
Vapor Pressure Measurements, Transpiration Method.
Vapor pressure of the liquid ketol and its enthalpy of vaporiza-
g
Crystal d ) (0.8370 ( 0.0004) mm, R ) 0.005
2
89.55
4.00
4.59
4.19
6.22
8.45
9.06
9.57
9.60
12.87
21600
19800
15002
18008
19800
18000
18000
14400
16260
0.8043
0.8009
0.8019
0.8085
0.8159
0.8123
0.8187
0.8228
0.8293
21.3
17.0
14.2
11.6
0.129
0.163
0.196
0.241
0.296
0.352
0.369
0.466
0.545
7
,8
tion were also determined by the transpiration method.
sample of approximately 0.5 g was mixed with glass beads
diameter of a bead was 1 mm) and placed in thermostated
U-tube of length 20 cm and diameter 0.5 cm. Preheated nitrogen
A
290.90
2
2
2
2
92.45
94.44
95.86
97.42
(
9.49
8.03
7.67
6.12
5.24
3
-1
stream with flow from (2 to 6) dm ‚h was passed through
the U-tube at constant temperature (( 0.1 K), and the transported
amount of material was condensed in a cooled trap (T ) 243
K). The amount of condensed substance (about 1 mg in each
experiment) was determined by GLC using an external standard
297.92
2
3
99.90
00.83
a
Temperature of saturation. b Mass loss. c Time of experiment. Trans-
d
mission probability factor. e Knudsen number. Saturated vapor pressure
f
(
linear hydrocarbon). Assuming that Dalton’s law of partial
corrected with respect to the isotropy failure theory and the condensation
coefficient. g Diameter of the effusion orifice.
pressures when applied to the nitrogen stream saturated with
the substance is valid, values of psat were calculated using the
equation
tion at 298.15 K were taken as those: ∆subH° ) (72.6 ( 0.6)
m
-
1
g
cr
-1
-1
kJ‚mol and 〈∆ C°〉 ) -(34 ( 2) J‚K ‚mol reported in
p
ref 10.
Vibration Spectra. The IR spectrum of crystalline ketol in
the range from (400 to 3500) cm (KBr pellets) and the IR
spectra for solutions of ketol in CCl4 (four sequential dilutions)
psat ) mRT /VM
(3)
a
-
1
where m is the mass of the transported substance; V ) VN +
Vketol, VN2 is the volume of nitrogen; Vketol is the volume
contribution of ketol to the gaseous phase (VN . Vketol); Ta is
the temperature of the soap film bubble flow meter. The vapor
pressure psat at each saturation temperature was calculated from
the amount of product collected within a definite time period.
The value of psat was corrected for the small value of the residual
vapor pressure at the temperature of condensation. The latter
correction was calculated from a linear correlation between ln
2
were recorded with a Bruker Vertex 70 spectrometer at T )
2
-1
2
90 K with resolution of 2 cm . The Raman spectrum in the
-1
range from (100 to 3500) cm of crystalline ketol was recorded
by a LabRam Raman microscope (HORIBA Jobin Yvon, Inc.)
at T ) 290 K.
Ab Initio Calculations. Calculation of the total energy of ketol
conformers as well as of their IR and Raman spectra were
performed with the Gaussian 03 Rev.C.02 series of the
-
1
psat and T obtained by iteration. We have checked experi-
1
1
program at the B3LYP/6-311G* level of theory.
mental and calculation procedures with measurements of vapor
8
pressures of l-alcohols. It turned out that vapor pressures
Results
derived from the transpiration method were reliable within (1
to 3) %, and their accuracy was governed by reproducibility of
the GLC analysis. However, in the case of the low-volatile ketol,
the reproducibility of the GLC analysis has been on the level
of 5 %.
Saturated Vapor Pressure, Enthalpy of Sublimation, and
Enthalpy of Vaporization of Ketol. The results of the effusion
experiments psat on the crystalline and the liquid ketol in the
temperature ranges from (289.6 to 300.8) K and from (308.2 to
3
30.4) K, respectively, are listed in Table 1. It should be
Sublimation Enthalpy Measurements, Calorimetry. The
enthalpy of sublimation of ketol was measured using a Calvet-
mentioned that an anomalous increase of ∆m has been observed
in effusion experiments above 330.4 K, apparently due to
decomposition of the sample in vacuum. But no traces of
decomposition have been observed during the transpiration
7
type microcalorimeter MID-200 with the uncertainty to within
0.5 %.9
(
The molar enthalpy of sublimation of ketol was calculated
5
experiments at T < 351.5 K in the inert gas stream (pN ≈ 10
using the equation:
∆subH° ) (K‚m)
2
Pa), as well as the ketol being stable in the benzene solution
during the sampling into injection port with a constant temper-
ature of 523 K. In the transpiration experiments, the sample of
ketol has remained liquid below its melting temperature 306.75
K down to 287.9 K. Thus, the psat values (see Table 2) were
measured in the temperature ranges from (287.9 to 303.0) K
and from (308.0 to 351.5) K, which covered the undercooled
and the liquid state of the ketol.
τ
-
1
M
∫
∆E dτ
(4)
m
τ)0
where m is the mass of the sublimed sample in vacuum; K is
the calorimetric constant of the cell; ∆E is a thermo-electromo-
tive force that is proportional to the difference to the temperature
imbalance between the cell and the thermostat of the calorimeter
at the time τ; ∫ ∆E dτ is the total signal value recorded
τ
τ)0
Vapor pressures measured by effusion and transpiration
techniques were fitted by
during the experiment.
The calorimetric constant of the cell was determined in series
of experiments with naphthalene (x ) 0.9999) for which
sublimation enthalpy and heat-capacity change during sublima-
-
1
T
To
ln(p /Pa) ) A + B(T/K) + C ln
/K
(5)
sat
[
(
)
]

1
948 Journal of Chemical and Engineering Data, Vol. 51, No. 5, 2006
Table 2. Saturated Vapor Pressure over the Undercooled and the
Liquid Ketol Determined by the Transpiration Method
Ta
mb
V(N2)c
pd
Ta
mb
V(N2)c
pd
K
mg
dm3
Pa
K
mg
dm3
Pa
e
e
e
e
287.9
293.2
298.0
303.0
308.0
311.1
313.1
316.2
318.2
321.2
323.3
325.2
328.2
330.2
331.3
1.35
1.51
1.78
1.13
0.97
1.08
0.88
1.20
0.89
1.04
0.96
1.21
0.66
1.29
1.39
105.5
67.80
47.09
21.17
12.20
10.18
7.20
7.15
4.82
4.28
3.03
0.17
0.29
0.49
0.71
0.99
1.34
1.53
2.09
2.34
3.05
3.95
4.03
5.40
5.67
6.05
333.3
336.2
337.4
338.4
340.2
341.3
342.6
344.6
345.4
347.0
348.4
348.6
350.5
351.5
1.45
1.07
1.13
1.01
1.49
1.14
1.63
1.30
1.38
1.03
1.64
1.09
1.40
0.94
2.22
1.50
1.50
1.21
1.56
1.14
1.36
1.00
0.93
0.71
1.03
0.67
0.70
0.49
8.16
8.86
9.49
10.42
11.85
12.49
14.80
16.13
18.32
18.08
19.81
20.13
24.99
23.78
Figure 1. Deviation of the experimental vapor pressure data for the liquid
and the undercooled ketol from the values calculated by eq 5. +, effusion
method data; O, transpiration method data.
3.72
1.52
2.81
2.86
has been calculated as their difference:
a
b
Temperature of saturation. Mass of transferred sample, condensed at
c
T ) 243 K. Volume of nitrogen, used to transfer mass m of sample.
Vapor pressure at temperature T, calculated from m and the residual vapor
pressure at the cooling temperature T ) 243 K. Temperature of under-
cooled liquid.
l
cr
-1
d
∆ H°(306.75) ) (21.4 ( 1.3) kJ‚mol
m
e
This value is in a good agreement with those obtained by the
2
l
Table 3. Enthalpy of Sublimation of Ketol Determined by the
Calorimetric Method
adiabatic calorimetry : ∆ H°(306.75) ) (20.81 ( 0.02) kJ‚
cr m
-
1
mol .
ma
T
∫
τ
τ)0
∆E dτb
Kc
∆ H°
m
g
cr
d
In the dimerization process two intramolecular hydrogen
bonds are changed to two intermolecular ones; therefore, ∆H
mV‚s‚J-1
kJ‚mol-1
mg
K
mV‚s
Crystal
1576.78
1510.75
≈
0 for this process. The entropy change in this process would
12
be comparable to -∆vapS°. So, the dimerization is an unfavor-
able process, and the vapor should consist of monomers. As a
possible argument for the absence of the dimers in the ketol
vapor could serve the behavior of ketol in the CCl4 dilute
solution studied by IR spectroscopy. Indeed, a narrow intensive
band of the OH bond involving in the intramolecular hydrogen
1
1
8.79
7.75
303.11
303.14
187.74 ( 0.66
190.00 ( 1.42
87.74
87.94
a
Mass of the sample corrected for buoyancy with the density of ketol d
3
-3 b
)
1.2‚10 kg ‚m
.
Total signal value recorded during the experiment.
c
d
g
cr
Calorimetric constant of the cell. 〈∆ H°(303.13 K)〉 ) (87.8 ( 1.8)
kJ‚mol
m
-
1
.
-
1
bond was detected in the region 3550 cm while the band of
the OH bond involved in intermolecular hydrogen bond in the
g
cond
g
cond
-1
g
-1
where B ) [∆ C°‚To - ∆ H°(To)]‚R , C ) ∆ C°‚R ,
To is the average temperature of each method, ∆ H°(To) is
the vaporization/sublimation enthalpy at To, ∆ C° is the
average difference between the heat capacities of the condensed
p
m
cond p
-
1
g
region 3600 cm was almost invisible.
cond
g
m
Enthalpy of sublimation of ketol at T ) 298.15 K derived in
cond
p
g
cr
-1
this work (∆ H° ) 88.4 ( 1.2 kJ‚mol ) together with the
m
g
l
-1
-1
g
cr
f
m
enthalpy of formation of crystalline ketol ∆ H° (cr, 298.15 K)
) -(597.6 ( 2.4) kJ‚mol available from our recent study
and vapor phase: ∆ C° ) -97.5 J‚K ‚mol , ∆ C° ) -36.8
p
p
-1
2
-
1
-1
J‚K ‚mol .
provides now the standard enthalpy of formation for the
substance in the gaseous state:
The parameters of the equations psat ) f (T) for each method
g
l
g
cr
as well as the values of ∆ H° (<T>) and ∆ H° (<T>) are
m
m
listed in Table 4. Relative deviations of the experimental vapor
pressure, measured by the effusion and the transpiration
methods, from eq 5 are shown in Figure 1. Most of the
experimental points deviate from the smoothing eq 5 by less
than ( 5 %, however some points show scatter up to ( 10 %.
Calorimetric value of the enthalpy of sublimation has been
measured with heat-conducting calorimeter (Table 3). Enthalpies
-
1
∆fH° (g, 298.15 K) ) -(509.2 ( 2.7) kJ‚mol
m
The entropies of the liquid and the crystalline ketol available
from our earlier work and the enthalpies of vaporization and
sublimation obtained in this study were used for the calculation
of the entropies of ketol in the ideal gas state. According to the
procedure described earlier, the experimental gaseous entropy
of ketol at 320.77 K, S° (g, 320.77) ) (490.6 ( 2.3)
J‚K ‚mol , and at 298.15 K, S° (g, 298.15) ) (475.0 ( 4.2)
J‚K ‚mol (Table S1, see Supporting Information) were
calculated. A residual entropy S°(T f 0) ) R ln 2 caused by
the existence of equivalent racemic mixture of two optical
isomers in the condensed state was taken into account.
2
g
13
of vaporization ∆ H° (<T>) and enthalpies of sublimation
l
m
g
cr
∆
H° (<T>) (see Tables 3 and 4) were adjusted to the
m
m
-
1
-1
temperatures 320.8 K and 298.2 K, respectively, with the use
of the average differences between the heat capacities of the
condensed and vapor state (see above). Moreover, the enthalpies
of vaporization and sublimation at the triple point temperature
were calculated in the same way, and the enthalpy of fusion
m
-
1
-1
Table 4. Parameters of Equation 5 for the Temperature Dependence of Vapor Pressure for the Crystalline and the Liquid Ketol
g
cond
-B
∆
H°(〈T〉)
m
kJ‚mol-
1
method
temperature range
A
K
-C
transpiration (liquid)
effusion (liquid)
effusion (crystal)
287.9 to 351.5 (〈T〉 ) 328.1 K)
313.05 to 330.40 (〈T〉 ) 320.8 K)
289.55 to 300.83 (〈T〉 ) 295.5 K)
37.12 ( 0.17
37.26 ( 0.46
39.31 ( 0.66
11641 ( 57
11577 ( 147
11993 ( 194
11.7 ( 0.4
11.7 ( 0.4
4.4 ( 0.3
64.8 ( 0.5
64.9 ( 1.2
88.8 ( 1.6

Journal of Chemical and Engineering Data, Vol. 51, No. 5, 2006 1949
Figure 2. Most stable conformer of 2-(1′-hydroxycyclohexyl)cyclohex-
anone.
Figure 4. Raman spectrum of crystalline ketol.
Table 5. Differences in the Energies of the Conformers of
2
-(1′-Hydroxycyclohexyl)cyclohexanone from ab initio Calculations
H (0 K)
kJ‚mol-1 xi (298.15 K)
∆
Figure 3. Newman projections of the conformers produced by rotation
around C(2)-C(7) and C(7)-O(14) bonds: a, the most stable at 0 K; b,
conformation of the ketol in the crystal lattice.
type of conformational motion
-
2
hindered rotation around C(7)-O(14) bond
hindered rotation around C(2)-C(7) bond
0
99.998‚10
-
-
5
2
26.6
2.15‚10
44.15‚10
55.63‚10
0.22‚10
0
Thermodynamic Properties for 2-(1′-Hydroxycyclohexyl)-
cyclohexanone in the Ideal Gas State. The procedure of
statistical thermodynamic calculations of the thermodynamic
properties in the ideal gas state was described in detail
-2
-
0.5
13.1
0
-
-
2
2
inversion of C(7)C(8)C(9)C(10)C(11)C(12) ring
inversion of C(1)C(2)C(3)C(4)C(5)C(6) ring
91.56‚10
-
5
2
2
2
2.5
6.8
4.9
11.5‚10
1.98‚10
4.27‚10
9.30‚10
-
5
1
3
-1
elsewhere. Molar mass of ketol M ) 196.286 g‚mol was
calculated using atomic weights of elements recommended by
IUPAC.14
-5
-
9
45.8
22.2
5
0
-5
13.1‚10
9.19‚10
98.94‚10
3.13‚10
-
-
2
2
.9
Ketol has one chiral C-atom (Figure 2, atom C(2)). The
following types of intramolecular motions are possible in a ketol
molecule: hindered rotation of -OH group with the forming
of two rotational isomers; hindered rotation of the rings around
the C(2)-C(7) bond with the forming of three rotational isomers
-4
25.4
9.89‚10-3
11.4
40.2
-
8
9.13‚10
-
6
2
2
1
8.4
5.5
9.0
10.5‚10
3.35‚10
4.66‚10
-
-
5
4
(Newman projections of the rotational isomers are shown in
Figure 3); and inversion of “cyclohexanol” and “cyclohexanone”
rings with the forming of the equatorial and axial “chair” ring
isomers and five “twist” isomers in each case. Relative energies
of the conformers Ei - E0 (E0 is the energy of conformer b,
see Figure 3) together with the mole fractions of the conformers
at 298.15 K are listed in Table 5. Optimization of geometry
and calculation of total energy of each the conformer was carried
out by quantum-mechanical methods. Zero-point vibration
energies were found with the use of the calculated vibration
frequencies scaled by a factor ø from eq 6 described below
crystal of the ketol is formed by molecules in the b conforma-
tion. The accordance between the experimental and the calcu-
lated values for the bands observed in the experimental spectra
was found with the use of calculated and observed intensities
of the absorption Raman and IR bands. The scaling factors ø
-
1
) wexp/wcalc for the range (100 to 3500) cm were fitted by
the following equation:
-
5
-1
ø ) (1.025 ( 0.002) - (4.22 ( 0.14)‚10 (w /cm ) (6)
calc
(Table S2, see Supporting Information). In the calculation of
the mole fractions, it was assumed that all types of intramo-
lecular motions are independent.
All the conformers belong to C1 group of symmetry. The
products of the principal moments of inertia (IAIBIC) are listed
in Table S3 (see Supporting Information).
Experimental absorption bands of Raman (Figure 4) and IR
spectra for the crystalline ketol and its IR spectrum in CCl4
solution (Figure 5) are listed in Table 6. From the comparison
of the experimental and calculated spectra, it was assumed that
The vibration frequencies invisible both in IR and Raman spectra
were assessed with the help of quantum-mechanical calculations
and the scaling factors ø from eq 6. The set of selected
fundamental frequencies for the b conformer obtained by
combining the experimental and theoretical results are listed in
Table 6.
Thermodynamic properties of ketol in the ideal-gas state in
the temperature range (50 to 1000) K are listed in Table 7. The
calculated entropy of ketol in the ideal gas state was S°(320.8
m

1
950 Journal of Chemical and Engineering Data, Vol. 51, No. 5, 2006
Table 6. Experimental and Calculated (B3LYP/6-311G*) Fundamental Frequencies for the b Conformer of Ketol
experimental
frequencies in cm
experimental
frequencies in cm
-
1
-1
IR
IR, soln in CCl4
Raman
ab initio, scaled
selected
IR
IR, soln in CCl4
Raman
ab initio, scaled
selected
6
9
1
1
61
91
1216
1236
1258
1216
1235
1257
1223
1237
1255
1246
1271
1293
1296
1304
1310
1325
1348
1355
1360
1376
1379
1376
1391
1394
1396
1404
1442
1483
1487
1497
1501
1507
1507
1510
1519
1524
1763
2985
2994
3012
3013
3022
3025
3026
3031
3035
3039
3051
3062
3064
3069
3070
3080
3085
3090
3101
3714
1216
1229
1257
1257
1263
1273
1298
1309
1319
1319
1333
1345
1345
1355
1355
1355
1359
1393
1428
1428
1434
1434
1448
1448
1448
1460
1460
1699
2848
2856
2863
2863
2892
2902
2902
2902
2902
2915
2921
2938
2938
2938
2938
2944
2944
2944
2959
3532
1
1
1
2
2
2
3
3
3
3
22
41
86
22
46
64
06
16
28
67
113
133
184
217
235
264
307
319
331
369
419
428
454
479
503
504
551
113
133
186
222
246
264
306
316
328
367
414
423
452
472
501
501
549
615
659
659
719
766
783
831
837
854
860
890
910
923
947
947
973
992
1026
1028
1041
1059
1064
1081
1095
1103
1129
1143
1157
1179
1267
1275
1295
1311
1263
1273
1298
1309
1319
1270
1275
1292
1319
1333
1325
1341
1345
1355
4
4
4
4
4
20
415
423
414
425
452
473
495
504
550
1345
1350
25
55
73
98
472
1351
1359
1397
1428
501
1401
1428
1393
1426
5
6
62
61
549
6
15
666
70
659
661
1440
1449
1434
1448
1440
1449
6
7
7
19
65
720
766
720
760
783
834
831
843
845
865
869
902
921
934
949
1465
1460
1699
1466
8
37
837
857
861
889
912
923
947
8
8
8
9
9
9
55
60
85
10
23
47
854
860
886
910
920
947
1689
2840
2861
1688
2848
2856
2892
2902
956
969
972
991
1007
044
046
1048
050
1082
1097
1120
1126
1152
1167
1187
1206
992
2901
1
1
2915
2921
1041
1036
1
2932
2944
3488
2938
1
1
1
1
1
1
1
1
066
080
100
113
132
146
157
182
1069
1075
1097
1110
1133
1144
1157
1183
1081
1103
1110
1129
1143
1157
1179
2936
2949
2959
2969
3489
3532
Table 7. Thermodynamic Properties of 2-(1′-Hydroxycyclohexyl)cyclohexanone in the Ideal Gas State
T
0
T
0
T
S°
C°
∆ H°/T
-∆ G°/T
-∆fHm°
∆fGm°
m
p,m
m
m
K
J‚K-1‚mol-1
J‚K-1‚mol-1
J‚K-1‚mol-1
J‚K-1‚mol-1
kJ‚mol-1
kJ‚mol-1
5
00
50
00
73.15
98.15
00
00
00
00
00
00
00
0
268.8
315.8
357.5
397.5
455.7
475.7
477.2
558.8
640.5
720.3
796.8
869.5
938.3
1003.3
53.7
86.4
40.3
55.0
71.3
228.5
260.9
286.2
309.0
340.5
351.0
351.8
393.3
434.6
475.6
516.1
555.7
594.5
632.1
454.0
468.9
480.1
490.5
505.0
509.6
509.9
525.7
537.1
544.7
548.9
550.3
549.4
546.7
-420.8
-381.3
-335.0
-285.1
-207.5
-180.1
-178.1
-65.0
51.7
170.2
289.7
410.2
529.5
1
1
2
2
2
3
4
5
6
7
8
9
121.6
158.7
218.7
240.4
242.0
328.2
405.3
469.8
522.7
566.0
601.7
631.3
88.5
115.2
124.7
125.5
165.5
205.9
244.7
280.8
313.8
343.9
371.2
1
000
649.3
-
1
-1
-1
-1
K) ) 494.0J‚K ‚mol and S°(298.2 K) ) 475.7 J‚K ‚mol
work, equilibrium of reaction I in the liquid phase K° (332.1
r(1)
K) ) 4.8‚10 was already reported. The values of the saturated
m
-2
2
(
Table S1, see Supporting Information).
Equilibrium of Cyclohexanone Dimerization and Equilib-
rium of Ketol Dehydration in the Vapor Phase. In our previous
vapor pressure of ketol obtained in this work together with those
1
5
for cyclohexanone allows now to estimate the equilibrium

Journal of Chemical and Engineering Data, Vol. 51, No. 5, 2006 1951
Table 8. Thermodynamic Properties of the Participants in Reaction
II in the Ideal Gas State (T ) 298.15 K)
property
ketol 2-(1-cyclohexenyl)cyclohexanone16 H2O15
-
1
-
∆fH°/kJ‚mol
509.6
475.7
217.2
492.4
241.8
188.8
m
-
1
-1
Sm°/J‚K ‚mol
were calculated with the use of the thermodynamic properties
for ketol in the ideal-gas state listed in Table 7 and those for
1
5
16
water and 2-(1-cyclohexenyl)cyclohexanone (Table 8). A
residual entropy S°(T f 0) ) R ln 2 caused by the existence of
equivalent racemic mixture of two optical isomers of 2-(1-
cyclohexenyl)cyclohexanone in the condensed state was taken
into account:
-
1
∆r(2)H°(298.15 K) ) 50.6 kJ‚mol
m
-
1
-1
∆r(2)S°(298.15 K) ) 205.5 J‚K ‚mol
m
K° ) 74.01
r(2)
5
At this temperature and p ) 10 Pa, the conversion of ketol is
rather low: equilibrium mole fractions of the participants are
x(ketol) ) 0.947; x(2-(1-cyclohexenyl)cyclohexanone) )
-
2
-2
2
.65‚10 ; x(H2O) ) 2.65‚10 . But since the reaction is
Figure 5. IR spectrum of ketol in CCl4 solution. The band of the OH-
bond adjacent to the intramolecular hydrogen bond is marked by an arrow.
endothermic, conversion of the ketol will increase with the
increase of temperature.
constant K°r(1) for reaction I in the vapor phase at 332.1 K:
Acknowledgment
K° (g, 332.1 K) ) K° (liq, 332.1 K) )
r(1)
r(1)
The authors are very grateful for the measurements by the
calorimetric method carried out by V. M. Sevruk.
pketol
5
-3
1
0 ) 2.4‚10 (7)
pcyclohexanone
Supporting Information Available:
Three additional tables. This material is available free of charge
via the Internet at http://pubs.acs.org.
where pi are the saturated vapor pressures for the pure
substances.
This constant has been also calculated using the thermody-
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1
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gratefully acknowledges
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(
JE0602768