Kinetics and Mechanism of the Oxidative Conversion of n-Amyl Alcohol to Valeric Acid on a Modified Zeolite Catalyst

Article abstract of DOI:10.1134/S0036024418040027

The catalytic activity of natural and synthetic mordenites modified with Cu²⁺, Zn²⁺, and Pd²⁺ cations via ion exchange was studied in the oxidative conversion of n-amyl alcohol to valeric acid under the action of oxygen. It is established that the highest activity and selectivity in this reaction is exhibited by mordenite hydrothermally synthesized from kaolinite and containing 3.0 wt % Cu²⁺, 0.1 wt % Pd²⁺, and 2.0 wt % Zn²⁺. The kinetics of this catalytic reaction is studied. Based on the experimental data, a possible stepwise mechanism is proposed, and a theoretically grounded kinetic model of the process is developed.

Full text of DOI:10.1134/S0036024418040027

ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2018, Vol. 92, No. 4, pp. 656–662. © Pleiades Publishing, Ltd., 2018.
Original Russian Text © A.M. Aliev, M.F. Bakhmanov, F.A. Agaev, V.Sh. Agaev, Z.A. Shabanova, A.R. Safarov, 2018, published in Zhurnal Fizicheskoi Khimii, 2018, Vol. 92, No. 4,
pp. 552–559.
CHEMICAL KINETICS
AND CATALYSIS
Kinetics and Mechanism of the Oxidative Conversion of n-Amyl
Alcohol to Valeric Acid on a Modified Zeolite Catalyst
A. M. Aliev*, M. F. Bakhmanov, F. A. Agaev, V. Sh. Agaev, Z. A. Shabanova, and A. R. Safarov
Nagiev Institute of Catalysis and Inorganic Chemistry, Baku, AZ1143 Azerbaijan
*e-mail: agil_s@mail.ru
Received March 17, 2017
Abstract—The catalytic activity of natural and synthetic mordenites modified with Cu2+, Zn2+, and Pd2+ cat-
ions via ion exchange was studied in the oxidative conversion of n-amyl alcohol to valeric acid under the
action of oxygen. It is established that the highest activity and selectivity in this reaction is exhibited by mor-
denite hydrothermally synthesized from kaolinite and containing 3.0 wt % Cu2+, 0.1 wt % Pd2+, and 2.0 wt %
Zn2+. The kinetics of this catalytic reaction is studied. Based on the experimental data, a possible stepwise
mechanism is proposed, and a theoretically grounded kinetic model of the process is developed.
Keywords: n-amyl alcohol, valeric acid, mordernite, mechanism, kinetic model, kinetic constants
DOI: 10.1134/S0036024418040027
INTRODUCTION
lyst’s surface. The heterogeneous partial oxidation of
aliphatic alcohols on the surfaces of metal–zeolite
catalysts occurs as the result of the interaction between
these alkoxide compounds and the surfaces’ nucleop-
hilic oxygen [9].
The aim of this work was to synthesize mordenite
from kaolinite by hydrothermal method, modify it
with Cu2+, Zn2+, and Pd2+ cations via ion exchange,
determine its composition active in the oxidative con-
version of n-amyl alcohol to valeric acid, and study the
kinetics and the mechanism of this reaction.
Valeric acid is a valuable organic acid. It is used to
produce medicines, food additives, and detergents. It
is also used for the syntheses of solvents (ethylvaler-
ate), fragrances and emulsifiers for synthetic materials
and plasticizers.
On an industrial scale, organic acids are obtained
via the heterogeneous catalytic oxidation of aliphatic
alcohols. The catalysts are metals (e.g., Cu, Ag, Au,
Fe, and Mo), transition metal oxides (e.g., CuO +
Cu2O, V2O5, Cr2O3, MoO3, etc.), along with mixed
oxides and the salts of transition metals (e.g., vana-
dates, tungstates, stannates, and molybdates of zinc,
cobalt, and bismuth). These processes occur in the
temperature range of 350–450°C and have relatively
low selectivity toward the target product [1–4].
EXPERIMENTAL
Catalysts were prepared from natural mordenite
(from the Azerbaijan deposit) with silicate modulus
λ = SiO2/Al2O3 = 9.6 and a crystallinity of 89.0%.
Synthetic mordenite (also from the Azerbaijan
deposit) was obtained via hydrothermal synthesis fol-
lowing the procedure described in [11]. An autoclave
was charged with 1 g of kaolinite, 2 g of volcanic ash,
2 g of silica gel, 1.75 g of butanediol-1,4, and 13 mL of
water. The pH of the mixture was adjusted to pH 11 by
adding NaOH dropwise. The reaction time at a tem-
perature of T = 170°C was t = 144 h. The zeolite’s type
and crystallinity were determined via X-ray diffraction
on a D-2 diffractometer (Bruker). The silicate modu-
lus and crystallinity of the mordenite synthesized in
this way were λ = 9.6 and 98.0%, respectively.
In [5–10], we showed that zeolites modified with
metal cations via ion exchange exhibit fairly high cata-
lytic activity and selectivity in the oxidative conversion
of aliphatic alcohols at relatively low temperatures
(250–350°C).
Based on a study of experimental data in the litera-
ture and on physicochemical means of analysis, it was
established that—like the liquid-phase variant of the
process, which is performed in an acid medium,
includes protons, and proceeds through the formation
of an intermediate compound (chromate ester)—the
heterogeneous vapor-phase partial oxidation of ali-
phatic alcohols on metal–zeolite catalysts also yields
surface alkoxides that form during the interaction
between medium-strength Brønsted acid sites with
In aqueous solutions of CuCl2, ZnCl2, and
[Pd(NH3)4]Cl2, zeolites were modified with Cu2+,
molecules of aliphatic alcohols adsorbed on the cata- Zn2+, Pd2+ metal cations via ion exchange. They were
656

KINETICS AND MECHANISM OF THE OXIDATIVE CONVERSION OF n-AMYL
657
Table 1. Test results for the catalytic activity of natural and synthetic mordenites and their Cu2+, Zn2+, and Pd2+-modified
forms in the oxidative conversion of n-amyl alcohol to valeric acid at the temperature of T = 280°C, the volumetric flow
rate of V = 2000 h–1, and the alcohol : O2 : N2 molar ratio of 1 : 1 : 3.8
Content of cations, wt %
Yield, %
No.
Zeolite
Х, %
Cu2+
Pd2+
Zn2+
A1
A2
A3
A4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Mor (natural)
11.9
23.3
32.5
32.6
48.2
47.5
53.1
51.1
16.4
30.5
36.6
36.9
57.8
56.7
64.9
61.7
6.7
18.9
26.2
25.6
37.5
36.1
42.6
39.2
10.2
24.6
29.1
28.4
43.8
42.4
51.4
47.3
0.6
1.7
2.4
2.2
3.6
3.4
4.4
4.1
0.8
2.2
2.8
2.6
4.7
4.4
5.5
4.9
4.3
1.9
2.6
3.2
4.9
5.1
3.7
5.3
4.7
2.6
3.1
3.8
5.6
5.8
4.9
6.1
0.3
0.8
1.3
1.6
2.5
2.9
2.1
2.5
0.7
1.1
1.6
2.1
3.7
4.1
3.1
3.4
1.0
3.0
4.0
3.0
3.0
3.0
3.0
0.1
0.2
0.1
0.1
2.0
3.0
Mor (synthetic)
1.0
3.0
4.0
3.0
3.0
3.0
3.0
0.1
0.2
0.1
0.1
2.0
3.0
A is valeric acid, A is valeric aldehyde, A is amylenes, A is CO , Х is conversion.
1
2
3
4
2
then dried (80–120°C, 5 h) and calcined for 30 min in region. The temperature range was 260–320°C, the
a stream of air at a temperature of 300°C and a volu-
volumetric flow rates were 1500–2500 h−1, and the
metric flow rate of 2400 h−1. The content of metal cat- partial pressures of the reagents were Palc = 0.1–
ions added to a zeolite was determined by mass spec-
trometry on an ICP-MS Agilent 7700 instrument.
0.4 atm and
= 0.1–0.3 atm. The purity of n-amyl
PO
2
alcohol (analytical grade) was 99.8%.
Experiments were performed on a flow-through
unit connected directly to the DB-624 column of an
Agilent 7820A gas-liquid chromatograph at a gas (He)
flow rate of 1.5 mL/min. The reactor, made of Pyrex
glass, had an inner diameter of din = 20 mm; the reac-
tor contained zones for preheating the initial reaction
mixture and for the products chilling. The reactor was
charged with 3 cm3 of catalyst with a particle size of
0.25–0.63 mm. The catalyst was activated in a nitro-
gen stream at 400°C for 3 h, after which the tempera-
ture was lowered to the temperature of the reaction,
and the reaction mixture was fed at the desired volu-
metric flow rate. Using an ME-1600 microdoser, the
initial materials were supplied to a mixer in a thermo-
statted cabinet equipped with an electric heater and a
fan. A stable temperature in the thermostat was main-
tained using a MICROMAX temperature microcon-
troller. The mixer was also supplied with oxygen and a
dilution gas (nitrogen). The reactor was placed in a
thermostatted cabinet. Reaction products were col-
lected at the reactor’s outlet from a sampling loop
connected to a six-port valve.
RESULTS AND DISCUSSION
On the basis of natural and synthetic mordenites
and cations of Cu2+, Zn2+, and Pd2+, catalyst samples
with different contents of these cations were synthe-
sized by means of ion exchange. Table 1 presents the
results from catalytic activity tests performed on some
samples, and on unmodified natural and synthetic
mordenites in the oxidative conversion of n-amyl alco-
hol to valeric acid.
It follows from the data in Table 1 that natural and
synthetic mordenites exhibit low catalytic activity in
the oxidative conversion of n-amyl alcohol to valeric
acid. The predominant reactions in this case is the
dehydration of n-amyl alcohol to amylenes (nos. 1 and
9). The yield of amylenes on synthetic mordenite is
higher than on natural mordenite due to the high crys-
tallinity (98.0%) of synthetic mordenite. For the same
reason, the catalytic activity of synthetic mordenite
modified with metal ions is higher in comparison to
natural mordenite (nos. 2–8 and 10–16).
The reaction kinetics was studied under conditions
Concentrations of the cations varied in a wide
that ensured the reaction proceeded in the kinetic range (1–4 wt %). It should be noted that the yield of
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658
ALIEV et al.
Table 2. Results from our study on the kinetics of the n-amyl alcohol oxidative conversion to valeric acid on the
CuZnPdMor (synth.) catalyst
Yield, %
V, h−1
P
alc
No.
T, °C
Х, %
PO
2
A1
A2
A3
A4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1500
1800
2000
2200
2500
1500
1800
2000
2200
2500
1500
1800
2000
2200
2500
1500
1800
2000
2200
2500
260
260
260
260
260
280
280
280
280
280
300
300
300
300
300
320
320
320
320
320
0.15
0.15
0.15
0.15
0.15
0.17
0.15
0.17
0.14
0.15
0.15
0.15
0.13
0.14
0.15
0.15
0.13
0.14
0.15
0.14
0.18
0.18
0.18
0.18
0.18
0.17
0.31
0.17
0.29
0.18
0.18
0.31
0.25
0.29
0.31
0.31
0.25
0.29
0.31
0.29
64.2
60.5
56.7
52.9
49.8
61.2
76.9
64.9
74.1
50.9
67.5
79.8
76.8
79.2
72.2
78.1
79.7
82.4
79.6
79.7
47.9
45.5
42.8
40.1
38.2
45.2
59.2
51.4
55.2
38.8
52.3
60.4
56.6
58.2
54.7
57.2
58.6
60.2
59.7
58.9
8.6
8.1
7.6
7.2
6.8
6.5
6.2
5.5
6.8
4.7
4.2
6.7
6.9
7.1
5.9
7.2
7.2
7.5
6.9
7.1
4.6
4.2
3.9
3.5
3.1
5.6
6.3
4.9
6.6
4.3
6.1
6.9
7.2
7.5
6.2
7.4
7.5
7.8
7.1
7.3
3.1
2.7
2.4
2.1
1.7
3.9
5.2
3.1
5.5
3.1
4.9
5.8
6.1
6.4
5.4
6.3
6.4
6.9
5.9
6.4
V is the volumetric flow rate, Х is conversion. For other notations, see Table 1.
individual products is greatly affected by the distribu-
tion of acid sites (the distribution of acid sites on the
surface changes when metal cations are introduced
into the zeolite) and by the concentration and nature
of a cation. Introducing copper cations into mordenite
increases the concentration of dissociatively adsorbed
oxygen molecules, raising the catalytic activity of the
zeolite in the considered reaction (nos. 2 and 10). As
the concentration of cations grows from 1.0 to
3.0 wt %, the yield of valeric acid rises from 18.9 to
26.2% (nos. 2 and 3) for natural mordenite and from
24.6 to 29.1% for synthetic mordenite. A further
increase in the concentration of copper cations (up to
4.0 wt %) has little effect on the yield of valeric acid
(nos. 4 and 12). This can be explained by a change in
the distribution of acid sites on the surface of the cata-
lyst, as the number of medium strength Brønsted acid
sites falls at relatively high concentrations of copper
cations.
Analysis of data given in Table 1 shows that the cat-
alyst obtained from synthetic mordenite (Mor.
(synth.)) via ion exchange and containing 3.0 wt %
Cu2+, 2.0 wt % Zn2+, and 0.1 wt % Pd2+ exhibits rela-
tively high activity in the oxidative conversion of
n-amyl alcohol to valeric acid (no. 15). The reaction
kinetics for this catalyst was studied with no inhibition
of diffusion. To determine the region of the reaction, a
series of experiments were performed at different sizes
of the catalyst grains (0.07–1 mm) and different linear
feed rates. The linear rate of the initial reaction mix-
ture was varied by changing the catalyst volume (from
3 to 6 cm3) while maintaining a constant volumetric
flow rate. The resulting experimental data showed that
the reaction proceeded in the kinetic region. Table 2
shows the results from our experimental study on the
kinetics of the oxidative conversion of n-amyl alcohol
to valeric acid on CuZnPdMor (synth.) catalyst.
It follows from the data in Table 2 that the oxida-
tion of n-amyl alcohol to valeric acid on these catalysts
is accompanied by the oxidative dehydrogenation of
n-amyl alcohol to valeric aldehyde, and by the deep
oxidation and dehydration of n-amyl alcohol to car-
bon dioxide and amylenes.
The introduction of small amounts of palladium
(0.1 wt %) and zinc (1.0–2 wt %) cations creates a dis-
tribution of acid sites on the catalyst’s surface that
favors the considered reaction (nos. 5–8 and 13–16).
In addition, these cations raise the concentration of
dissociatively adsorbed oxygen molecules.
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KINETICS AND MECHANISM OF THE OXIDATIVE CONVERSION OF n-AMYL
659
(1)
+O2
Analysis of the effect the volumetric flow rate has
C4H9COOH + H2O
on the yields of valeric acid and valeric aldehyde
(Tables 2, nos. 1–5) shows that valeric acid does not
form from valeric aldehyde via a sequential mecha-
nism.
+0.5O2
+O2
C4H9CHO + H2O
C5H10 + H2O
C5H11OH
5CO2 + 6H2O
Our experiments allow us to propose the following
kinetic scheme of the reactions that occur during the
oxidative conversion of n-amyl alcohol on CuZnPdMor
(synth.) catalyst:
Based on an analysis of the literature data [9], we can
propose a stepwise mechanism for the formation of
valeric aldehyde and valeric acid:
H
H
H
C4H9
Me2+
C
OH2
C4H9
C
OH
+C4H9
C
OH
H
1
+
O2
H
H
2
Me2+
Me2+ ON2−
H+
H
Me2+ ON2−
H+
H+
ON2−
H
C
C4H9
C
O
H
C4H9
H
1
2
+
O2
O
H
+ C4H9
C
Me2+
−H2O
H+
Me2+
ON2−
O
ON2−
Me2+
H
C
O
H
C4H9
Me2+
1
2
+
O2
OH
+ C4H9
C
O
ON2−
ON2−
Me2+
H+
H+
According to this scheme, the adsorption of n-amyl All of these stages are virtually irreversible. Assuming
alcohol is accompanied by its protonation on Brønsted their elementarity, we write the expressions for stage
acid sites of the catalyst with the subsequent release of rates:
water and the formation of a surface alkoxide. The sur-
face alkoxide transforms into valeric aldehyde via the
formation of an aldehyde-like surface compound by
reacting with surface nucleophilic oxygen. The alde-
hyde-like surface compound then breaks down to form
valeric aldehyde. Valeric acid forms in the reaction
between the aldehyde-like surface compound and the
surface nucleophilic oxygen.
r = k1PO θ12, r2 = k2P θ2, r = k3θ3,
1
alc
3
2
(3)
r4 = k4θ4, r = k5θ4P1/2
.
O2
5
Here, θ1, θ2, θ3, and θ4 are fractions of the following
regions of the modified zeolite, respectively: free
regions that can absorb oxygen, regions covered with
atomic sorbed oxygen, regions covered with atomic
sorbed oxygen and molecules of n-amyl alcohol, and
regions covered with aldehyde-like intermediates
For convenience in formulating kinetic equations,
the above scheme can be presented in the form
Z(C H COH).
and
are partial pressures of the
P
alc
P
4
9
O2
1
k1
O2 + 2Z ⎯→2ZO
respective components; k1, k2, k3, k4, and k5 are the
rate constants of the respective stages; and r1, r2, r3, r4,
and r5 are the rates of the respective stages.
k2
2
ZO +C H OH ⎯→ZO C H OH
(
4
)
)
5
11
5
11
k3
2
1
(2)
ZO C H OH ⎯→ Z C H CHO + H O
(
4
)
(
4
5
11
9
2
Under stationary conditions,
k4
Z C H CHO ⎯→ C H CHO + Z
(
)
9
9
(4)
r = r = r2 = r = r4 = r ,
1
3
5
1
2
k5
Z C H CHO + O ⎯→C H COOH + Z
(
)
4
9
2
4
9
1
where r is the overall rate of the process.
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A Vol. 92 No. 4 2018

660
ALIEV et al.
Based on these equations and the constancy of the kinetic equation corresponding to this mechanism has
total number of surface regions (θ1 + θ2 + θ3 + θ4 = 1), the form
the concentrations of intermediates θi and the rates of
formation for valeric aldehyde (rv.ald) and valeric acid
(rv.ac) can be found as the functions of the reactants:
k6K1K2P P
O2 alc
.
(11)
rCO
=
2
2
1 + K P + K P
(
)
1
O2
2 alc
Here, k6 is the rate constant of carbon dioxide forma-
tion and K1 and K2 are the constants of the adsorption
equilibrium of molecules of oxygen and n-amyl alco-
hol on active sites.
Amylenes form as a result of the reversible dehy-
dration reaction of n-amyl alcohol. The observed rate
k4θ4
k4θ4
k4θ4
k3
(5)
θ1 =
;
θ2 =
;
θ3 =
.
k1PO
k2P
alc
2
Writing θ4 = y2, we get:
⎛
⎜
⎞
k4
k4
k3
k4
+ 1 y2 +
y −1 = 0,
(6)
+
of this reaction is
⎟
k P
k1PO
⎝
⎠
2
alc
2
ꢀ
ꢁ
ꢀ
ꢁ
r
ꢁ
r
(12)
r = r − r = r 1 −
)
(
⎡
k4
k1PO
y = −
⎢
and
⎣
2
ꢀ
⎤
⎡ ⎛
P
P
⎛
⎞
k4
k4
k4
k4
C5H10 H2O
r
(7)
+
+ 4
+
+ 1 / 2
,
= γ
(13)
(14)
1 − = 1 −
⎥
ꢁ
⎜
⎟
⎜
⎢
k2P
k P
k3
⎞⎤
k P
r
KP P
⎝
⎠
⎣ ⎝
O2
2
alc
2
alc
alc
⎦
ꢀ
k4
k3
r = rγ,
+
+ 1
.
⎟
⎥
⎠⎦
where γ is the irreversibility criterion. Given that the
rate of the forward reaction is
ꢀ
(15)
(16)
r = kP ,
For simplicity, we introduce the notation
alc
by substituting (15) and (13) into (14), we obtain
k4
;
A' = −
P
P
⎛
⎞
C5H10 H2O
k1PO
2
r = kP 1 −
alc
⎜
⎟
KP P
⎝
⎠
alc
⎛
⎞
k4
k2PO
k4
k4
k3
⎛
⎞
1
KP
;
B' =
+ 4
+
+ 1
= k P
−
P
PH O
.
⎜
⎟
alc
C5H10
⎜
⎟
2
k P
⎝
⎠
2
alc
2
⎝
⎠
Considering the deceleration of the reaction rate by
adsorbed molecules of alcohol and water, the observed
reaction rate is
⎛
⎞
k4
k4
k3
.
C' =
+
+ 1
⎜
⎟
k P
⎝
⎠
2
alc
Then
1
KP
P
−
P
P
alc
C5H10 H2O
2
A' + B'
2C '
(17)
rC H = k7
,
⎡
⎤
5
10
.
(8)
θ4 =
K3P + K4P
alc
H2O
⎢
⎥
⎣
⎦
where KP is the equilibrium constant of n-amyl alcohol
By substituting θ4 into the corresponding rate equa-
tions, we obtain equations for the rate of valeric alde-
hyde formation:
dehydration
(18)
log KP = −A + B T ,
in which А and В are empirical constants derived from
experimental data (А = 3.36 and В = 2684.6); K3 and
K4 are constants of the adsorption equilibrium of alco-
hol and water molecules, respectively, on the active
sites of the catalyst in the dehydration of n-amyl alco-
hol; and k7 is the rate constant of dehydration.
⎡A' + B'⎤2
(9)
rv.ald = k4
.
⎥
⎢
2C'
⎣
⎦
For the rate of valeric acid formation,
1/2 ⎡A' + B'⎤2
Arrhenius dependences were used to calculate con-
stants k and K:
.
⎥
⎦
(10)
rv.ac = k5P
O2
⎢
⎣
2C'
E
RT
Q
k = k0e−
,
K = K0eRT
.
If we assume that the formation of carbon dioxide pro-
ceeds when weakly adsorbed molecules of n-amyl
(19)
alcohol react with adsorbed oxygen molecules and fol- Based on kinetic scheme (1), we can write the gross-
lows the Langmuir–Hinshelwood mechanism, the stoichiometric equations for the formation of valeric
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KINETICS AND MECHANISM OF THE OXIDATIVE CONVERSION OF n-AMYL
661
Table 3. Numerical values of the kinetic model constants for
the oxidative conversion of n-amyl alcohol to valeric acid
Here, A1–A4 are the yields of reaction products
(valeric acid, valeric aldehydes, amylenes, and carbon
dioxide).
ln k0, ln K 0
No.
E, Q, kcal/mol
The total volume of reagents is
ln k10
ln k20
ln k30
ln k40
ln k50
ln k60
ln k70
ln K10
ln K20
ln K30
ln K40
1
2
6.86
E1
E2
E3
E4
E5
E6
E7
Q1
Q2
Q3
Q4
2.95
n = nalc + nv.ac + nv.ald + n
i
C5H10
∑
2.23
3.18
2.00
2.86
1.99
(22)
+ nCO + nN0 + nO + nH O
.
3
2
2
2
2
4
−1.43
1.83
The partial pressure of reagents is expressed by the
equation
5
2.58
16.09
13.99
5.99
4.89
1.50
6
25.18
13.59
−17.06
−3.29
2.66
(23)
P = n / n P,
(
)
i
i
i
∑
7
where P is the total pressure of 1 atm.
8
The kinetic model of the oxidative conversion of
n-amyl alcohol to valeric acid on the CuZnPdMor
(synth.) zeolite catalyst thus has the form
9
10
11
2.26
1.50
1/2 ⎡A' + B'⎤2
⎫
dA
1
= k5P
⎪
⎪
⎪
⎪
⎪
⎪
⎬
⎪
⎪
⎪
⎪
⎪
⎪
⎭
O2
⎢
⎥
d G /n0
2C'
(
)
)
⎣
⎦
k
alc
aldehyde, valeric acid, amylenes, and carbon dioxide
from n-amyl alcohol:
⎡A' + B'⎤2
dA2
= k4
⎢
⎣
⎥
⎦
d G /n0
1
2
2C'
(
C5H11OH + O2 → C4H9CHO + H2O,
k
alc
(24)
1
KP
P
−
P P
C5H10 H2O
C5H11OH + O2 → C4H9COOH + H2O,
alc
(20)
dA3
= k7
C5H11OH → C5H10 + H2O,
d G /n0
K3P + K4P
alc
H2O
(
)
)
k
alc
1
2
C5H11OH + 7 O2 → 5CO2 + 6H2O.
k6K1K2P P
dA4
O2 alc
=
2
d G /n0
Using these equations, we determine the yields of
1 + K P + K P
(
(
)
k
alc
1
O2
2 alc
reaction products, the initial molar amounts of n-amyl
na0lc
nО0
, and the current molar
where
is the mass of the catalyst.
Gk
alcohol
and oxygen
quantities of reagents in the2flow using the equations
0
Pre-exponential factors of the rate constants (
ln ki
nalc = na0lc − A n0 + A2na0lc + A3na0lc + A4na0lc
and
0 ), activation energy values ( ), and adsorp-
(
)
ln Ki
Ei
1
alc
= na0lc − na0lc A + A + A + A 100,
tion heat values ( ) were calculated by means of flex-
Q
ible tolerance anid the Powell method using the
POISK software [12]. The objective function was
(
)
1
2
3
4
nv.ac = A na0lc 100,
1
nv.ald = A2 na0lc 100,
2
exp
calc
m
n
⎛
⎞
Aji − Aji
(25)
F = min
.
⎜
⎟
∑∑⎜
exp
⎟
nC H = A3 na0lc 100,
A
j=1 i=1
ji
⎝
⎠
5
10
exp
calc
nCO = 5A4 na0lc 100,
Here,
and
are experimental and calculated
A
A
ji
(21)
ji
2
yields of the ith component in the jth experiment, m is
the number of experiments, and n is the number of
components.
nN = nN0 ,
2
2
0
0
nO = nO0 − A na0lc
+
A2nalc + 7 A4nalc 100
1
2
1
2
0
Numerical values for the parameters of the kinetic
model are listed in Table 3.
1
(
)
2
2
= nO0 − A2 + A2 + 7 A4 nalc 100,
1
2
1
2
)
(
2
Our kinetic model for the oxidative conversion of
n-amyl alcohol to valeric acid describes the experi-
mental data satisfactorily. The average relative error
of the experimental and calculated data does not
exceed 5%.
nH O = A n0 + A2na0lc + A3na0lc + 6A4na0lc 100
(
)
1
alc
2
= na0lc A + A + A + 6A 100.
(
)
1
2
3
4
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A Vol. 92 No. 4 2018

662
ALIEV et al.
7. A. M. Aliyev, Z. A. Shabanova, and F. V. Aliyev, Eur.
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Translated by Yu. Modestova
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 92
No. 4
2018