Kinetics of allyl chloride epoxidation with hydrogen peroxide catalyzed by extruded titanium silicalite

Article abstract of DOI:10.1134/S0023158414060135

A mechanism is suggested for the heterogeneous catalytic epoxidation of allyl chloride with hydrogen peroxide in methanol. The kinetics of allyl chloride oxidation into epichlorohydrin in the presence of extruded titanium silicalite has been investigated. A kinetic model of the process has been derived from experimental data, and the activation energies of the target and side reactions, the rate constants of the reactions, and the adsorption equilibrium constant have been determined. The allyl chloride epoxidation process has been tested using a bench-scale continuous apparatus, and the adequacy of the kinetic model has been estimated.

Full text of DOI:10.1134/S0023158414060135

ISSN 0023ꢀ1584, Kinetics and Catalysis, 2014, Vol. 55, No. 6, pp. 712–721. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © A.V. Sulimov, S.M. Danov, A.V. Ovcharova, A.A. Ovcharov, V.R. Flid, 2014, published in Kinetika i Kataliz, 2014, Vol. 55, No. 6, pp. 730–740.
Kinetics of Allyl Chloride Epoxidation with Hydrogen Peroxide
Catalyzed by Extruded Titanium Silicalite
,
A. V. Sulimova *, S. M. Danova, A. V. Ovcharovaa, A. A. Ovcharova, and V. R. Flidb
aNizhni Novgorod State Technical University, Nizhni Novgorod, 603950 Russia
b Moscow State University of Fine Chemical Technologies, Moscow, 119571 Russia
* eꢀmail: epoxide@mail.ru
Received March 24, 2014
Abstract—A mechanism is suggested for the heterogeneous catalytic epoxidation of allyl chloride with
hydrogen peroxide in methanol. The kinetics of allyl chloride oxidation into epichlorohydrin in the presence
of extruded titanium silicalite has been investigated. A kinetic model of the process has been derived from
experimental data, and the activation energies of the target and side reactions, the rate constants of the reacꢀ
tions, and the adsorption equilibrium constant have been determined. The allyl chloride epoxidation process
has been tested using a benchꢀscale continuous apparatus, and the adequacy of the kinetic model has been
estimated.
DOI: 10.1134/S0023158414060135
Among the
α
ꢀoxides, epichlorohydrin (ECH) is the conventional, chlorohydrinꢀbased ECH producꢀ
the world’s third most abundant industrial product, tion method. The most significant of them are that the
exceeded only by ethylene oxide and propylene oxide. new method needs no solvent and makes it possible to
The world ECH output is estimated at >1.8 million reduce the chlorine consumption by 50% and the
tons per year [1]. Owing to its molecule having an water consumption by 70% and to diminish the formaꢀ
epoxide group and a mobile chlorine atom, ECH tion of chlorineꢀcontaining byꢀproducts (on the averꢀ
reacts readily with various classes of compounds, makꢀ age, by 80%). Significant disadvantages of this process
ing it possible to synthesize a number of ECHꢀbased are its relatively low selectivity for dichloropropanol
products demanded by many industries (epoxy resins, formation from glycerol and low hydrogen chloride
varnishes, glues, synthetic fibers, rubbers, etc.) [2, 3]. and glycerol conversions into the target product [5].
While ECH is used to obtain a really wide variety of Note also that the second stage of the process—
products, over 80% of the ECH output is consumed in alkaline dehydrochlorination of dichloroproꢀ
epoxy resin production [4].
panols—is the same as the final stage of the chloꢀ
rohydrin process, with all of its inherent drawꢀ
backs, including the formation of large amounts of
polluted wastewater. Considering the favorable
shortꢀterm outlook for the market prices of glycꢀ
erol, this technology is economically very attracꢀ
tive; however, in view of the progressive toughenꢀ
ing of environmental regulations, its longꢀterm
prospects are ambiguous.
At present, the main industrial method of producꢀ
ing ECH is the chlorohydrin process. This process,
known since the middle of the 20th century, suffers
from a number of serious drawbacks, including a small
chlorine utilization coefficient and use of extremely
diluted aqueous solutions of reactants at the
hypochlorination and dehydrochlorination stages.
This leads to a decrease in the output capacity of the
apparatuses and to the formation of large amounts of
In the context of the presentꢀday environmental
contaminated wastewater containing СаСl2. Furtherꢀ and economic situation, there is a severe need for new
more, the process yields considerable amounts of technologies that could replace the existing processes
organochlorine impurities, whose removal is very that produce large amounts of toxic waste. The main
laborious and expensive.
efforts in this area are aimed at designing new, efficient
catalytic systems and at developing upꢀtoꢀdate methꢀ
ods of producing oxygenꢀcontaining compounds using
these catalysts.
Special attention is deserved by the technology
developed by Solvay and Dow companies [4], which
independently suggested an ECH synthesis method
based on glycerol, which is the main byꢀproduct in the
The most interesting method of producing ECH
production of biodiesel from vegetable and animal is the liquidꢀphase epoxidation of allyl chloride
fats. This method offers appreciable advantages over (AC) with hydrogen peroxide (HP), an environꢀ
712

KINETICS OF ALLYL CHLORIDE EPOXIDATION
713
mentally friendly oxidizer, in the organic solvent
methanol (M) in the presence of titanium silicalite
[6, 7]:
2
1
+ H2O2
H2C CH CH2
Cl
(I)
+ H2O.
H2C CH CH2
O
Cl
The formation of the target product, ECH, via
reaction (I) is accompanied by a number of side reacꢀ
tions
yielding
1ꢀchloroꢀ3ꢀmethoxypropanꢀ2ꢀol
4000 3500 3000 2500 2000 1500 1000 500
Wavenumber, сm–1
(CMP), 1ꢀchloropropaneꢀ2,3ꢀdiol (CPD), and small
amounts of other compounds:
Fig. 1. IR spectra of the catalyst (1) before and (2) after
molding.
+
H2C CH CH2
H3C OH
O
Cl
H2C CH CH2
OH Cl
(II)
,
The heterogeneous epoxidation catalyst was
extruded titanium silicalite (cylindrical granules 2 mm
in diameter and 5 mm in length) prepared using a proꢀ
cedure developed by us [12, 13]. The extrudate was
prepared from titanium silicalite powder with an averꢀ
age particle size of 200–300 nm obtained as described
O
CH3
+ H2O
.
H2C CH CH2
H2C CH CH2
OH OH Cl
(III)
O
Cl
In addition, one of the reaction products is oxygen, in earlier works [14–16]. The binder was aluminum
which results from the reaction
2Н2О2 → 2Н2О + О2.
5,6ꢀoxynitrate. Powder and granular catalyst samples
were characterized by Xꢀray diffraction and IR specꢀ
troscopy. The morphology of the samples was studied
by scanning electron microscopy (SEM) and lowꢀ
temperature nitrogen adsorption.
(IV)
In recent years, there have been many patents dealꢀ
ing with this ECH synthesis method [8–11]. However,
insufficient data have been reported in openꢀaccess
publications and part of them is sparse and contradicꢀ
tory. Note also that the great majority of the publicaꢀ
tions consider a microcrystalline heterogeneous cataꢀ
lyst finely dispersed in a reaction mass, while ECH
manufacturers would prefer a molded catalyst that is
capable of operating in a fixed bed, obviating the need
for catalyst separation from the reaction mixture. This
prompted us to study the kinetics of the liquidꢀphase
epoxidation of allyl chloride with an Н2О2 solution in
an organic solvent in the presence of extruded titaꢀ
nium silicalite as the heterogeneous catalyst and to
construct a kinetic model of this process.
The kinetics of the process was investigated using a
laboratoryꢀscale setup involving a continuous, cataꢀ
lytic, fixedꢀbed, flow reactor. the reactor was stainlessꢀ
steel tubeꢀinꢀtube apparatus with an inner diameter of
15 mm and a length of 250 mm, filled with granular
titanium silicalite. For the uniform distribution of the
entering stream over the cross section of the reactor,
the bottom part of the latter was filled with glass Fenꢀ
ske helices. The reactor was temperatureꢀcontrolled
using a liquidꢀbath ultrathermostat. It had thermoꢀ
couple wells for monitoring the temperature profile
along the catalyst bed height. A pressure of 2.5–
3.5 atm was maintained in the reactor and in the entire
system. The feed flow rate was regulated by means of
electronic control of the pump. After a certain volume
of the reaction mixture was passed through the reactor
to bring it into the steadyꢀstate operating regime, we
began sampling the mixture leaving the reactor.
EXPERIMENTAL
The following chemicals were used in this study:
methanol (analytical grade, RF state standard GOST
2222ꢀ95), epichlorohydrin (pure grade, USSR state
standard GOST 12844ꢀ74), hydrogen peroxide soluꢀ
tion (specialꢀpurity grade, specifications TU 2611ꢀ
069ꢀ05807977ꢀ2006), allyl chloride (TU 6ꢀ01ꢀ753ꢀ
77), tetrabutyl orthotitanate (TU 6ꢀ09ꢀ2738ꢀ89), tetꢀ
raethyl orthosilicate (TU 2435ꢀ419ꢀ05763441ꢀ2003),
and tetrapropylammonium hydroxide obtained by
The components of the reaction mixture were
quantified by GLC on a Khromos GKhꢀ1000 chroꢀ
matograph (Khromos, Russia) fitted with a flameꢀionꢀ
ization detector and with a metallic column (2 m
×
3 mm) packed with ChromatonꢀNꢀAWꢀDMCS (0.2–
passing tetrapropylammonium bromide (98%, Acros) 2.25 mm) supporting the liquid chromatographic
through an ionꢀexchange column.
phase Reoplexꢀ400 (15% of the support mass). Hydroꢀ
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

714
SULIMOV et al.
taining zeolite—as a result of the introduction of the
Al2O3 binder. In addition, the diffraction pattern of the
granular sample exhibits stronger reflections at 31.12
and 32.66 , which, according to file no. 09ꢀ0440 in the
JCPDS database, are due to aluminum oxide.
°
°
The morphology of catalyst powder samples was
studied by examining them under a Hitachi Sꢀ2500
(Hitachi, Japan) scanning electron microscope with a
JNCA (Oxford Instruments, United Kingdom)
energyꢀdispersive Xꢀray microanalysis attachment.
Based on SEM data for over 250 particles, we conꢀ
structed particleꢀsize distribution histograms for the
powder catalyst. Statistic processing of these data
demonstrated that the average particle size for the
powder catalyst is 255 nm with a distribution width of
25 nm.
1
2
10
15
20
25
30
35
40
45
50
2
θ
, deg
The specific surface area, total pore volume, and
pore volume distribution over pore size for the powder
and granular samples were measured on a TriStar 3020
(Micromeritics, United States) gas adsorption anaꢀ
lyzer. From these data, we calculated, in the online
mode, porous structure parameters for the catalyst
samples using the BET method (Table 1).
Fig. 2. Xꢀray diffraction patterns of the catalyst (
and ( ) molding.
1
) before
2
gen peroxide was determined by iodometric titration
[17].
To estimate the catalytic constituent of the process,
we carried several runs in the absence of a catalyst in
the reactor packed with an inert massꢀtransfer
RESULTS AND DISCUSSION
An examination of the IR spectra of catalyst samꢀ
ples (Fig. 1), which were recorded in air at room temꢀ
perature using the KBr pellet technique in the 400–
4000 cm–1 range on an IRAffinityꢀ1 FTIR spectromeꢀ
ter (Shimadzu, Japan), demonstrated that the posiꢀ
tions of the characteristic peaks of powder and granuꢀ
lar titanium silicalite samples coincide fully in the
region of the 540 and 960 cm–1 bands.
material (Fenske helices) at 60
°C at a feed flow rate of
3.33
×
10–5 L/s. The hydrogen peroxide conversion in
the noncatalytic process did not exceed 0.2–0.3%.
Therefore, the noncatalytic hydrogen peroxide conꢀ
version under the given conditions can be neglected.
Under the same conditions, we studied side reactions
(II)–(IV) occurring in the corresponding systems. In
the absence of a catalyst, the rates of these reactions
were found to be negligibly low. For this reason, in furꢀ
ther analysis we considered only the catalytic constitꢀ
uent of the processes.
An earlier experimental study of allyl chloride
epoxidation under gradientless conditions [18] demꢀ
onstrated that this reaction is firstꢀorder with respect
to olefin and is fractionalꢀorder with respect to hydroꢀ
gen peroxide. It was established that the resulting
epoxidation products decrease the rate of the target
reaction. In order to estimate the effects of RCH and
water on the kinetics of the process catalyzed by
extruded titanium silicalite, we carried out an addiꢀ
tional series of experiments at various concentrations
of the products (ECH and water). The resulting ECH
was observed to slow down the target reaction, while
the variation of the water concentration in the reaction
mass in the 4.15–8.05 mol/L range in ECH synthesis
does not exert any noticeable effect on the process
rate. These findings are in good agreement with the
mechanism that we suggested for the formation of the
target epoxide (scheme).
The Xꢀray diffraction patterns of the powder and
granular catalyst samples, which were obtained on an
LAB XRDꢀ6000 (Shimadzu) diffractometer (Cu
K
α
radiation, nickel filter, scintillation counter, voltage of
30 kV, current of 30 mA) in the = 10 –80 range at
2
θ
°
°
a scanning rate of 2 deg/min with 0.02ꢀdeg increꢀ
ments, show the same reflections in the characteristic
2 range from 23° to 25° (Fig. 2). The peak intensity
in the diffraction pattern of the granular catalyst is
somewhat lower, which is likely due to the decrease in
the amount of the major component—titaniumꢀconꢀ
θ
Table 1. Characteristics of the porous structure of the titaꢀ
nium silicalite catalyst
Specific
Pore
Form of catalyst
surface area, m2/g volume, cm3/g
Powder
316.66
268.83
0.182
0.155
Granules
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

KINETICS OF ALLYL CHLORIDE EPOXIDATION
H
715
R
R
H
R
H
O
O
O
Si
Si
Si
Si
Si
Si
Si
OH
Si
OH
Si
Si
O
O
O
O
O
O
O
O
ROH
H O
2
H C=CH–R
2 1
2
+
+
Ti
Ti
Ti
O
Ti
–ROH
O O
O
O
O
R
O
O O
O
R
O
Si
Si
Si
Si
Si
Si
H2C
H
H
O
CH
H
H
R1
R
H
Si
O−
O
Si
Si
O
O
H
Ti
O
≠
≠
O+
H
CH2 HC
R1
(I)
O
O
R
R
H
R
H
O
Si
O
Si
Si
Si
Si
δ
–
H
O
O
O
O–
δ
O
O
Ti
O
Si
Ti
H
Si
O
rateꢀlimiting
step
O
O
H
H
CH2 O+
δ
H
O
Si
Si
δ
Si
O−
O +
R
H
H2C
O
R
CH
R1
Si
Si
H
CH
R1
O
O
Ti
H
H
O+
CH2 HC
O
O
R
Si
O
R1
H
(II)
(III)
R
H
O
Si
Si
O
O
O
+
+ H2O,
Ti
O
H2C CH R1
O
O
Si
Si
R
H
where R = –СН3, –CH2Cl.
1
Scheme. Mechanism of allyl chloride epoxidation with hydrogen peroxide in methanol in the presence of titaniu
According to the scheme, allyl chloride epoxidaꢀ The mechanism of this interaction is similar to the
tion with hydrogen peroxide takes place on tetracoorꢀ action of Ziegler–Natta catalysts in ꢀolefin polymerꢀ
α
dinated titanium atoms and proceeds via the formaꢀ ization. A distinguishing feature of allyl chloride inserꢀ
tion of an intermediate complex involving a solvent tion into the peroxotitanium bond is the possibility
molecule. It is known from the literature [19] that the of the formation of a fiveꢀmembered cyclic transiꢀ
action of hydrogen peroxide on titanium(IV) comꢀ tion state at the rateꢀlimiting step. This interaction
pounds typically yields peroxide bonds. In the epoxiꢀ yields, on the catalyst surface, oxonium forms of
dation with hydrogen peroxide in the presence of complexes I and II, which are in equilibrium with
titanium silicalite, the Ti–O–Si fragment likely one another. The formation of the reactive species
dissociates reversibly to yield the peroxotitanium II of the ꢀcomplex is facilitated by the existence
σ
bond Ti–OOH and Si–OH. A methanol molecule of hydrogen bonds between the silicate and peroxꢀ
participates actively in the stabilization of the perꢀ ide groups.
oxotitanium bond. The subsequent attack of an
olefin molecule on the catalytic site yields a
The conversion of species II into the initial comꢀ
plex between the catalyst and the solvent, which is
accompanied by the formation of reaction products,
π
ꢀcomplex.
A catalytically important step is the subsequent occurs via the “pushꢀandꢀpull” mechanism of electroꢀ
change of the bond type from the initial ꢀinteraction philic intramolecular substitution at the carbon atom
to the Ti–C ꢀbond. This change is accompanied by SEi). As follows from the structure of the transition
the effective transfer of the –OOH ligand from Ti to C. state III, the “pulling” action on the leaving complex
π
σ
(
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

716
SULIMOV et al.
side reactions (L s–1 g–1);
tion coefficients for hydrogen peroxide and epichloroꢀ
hydrin, respectively (L/mol); CHP CAC CECH M, and
W are the hydrogen peroxide, allyl chloride, epichloꢀ
bHP and bECH are the adsorpꢀ
Table 2. Dependence of the hydrogen peroxide conversion
on the catalyst particle size
,
,
, C
Hydrogen peroxide conversion, %
C
Catalyst particle
size, mm
rohydrin, methanol, and water, respectively (mol/L).
In order to determine the parameters of the model
suggested and to check its adequacy, we carried out
several series of experiments differing in initial condiꢀ
tions. In these experiments, we varied the catalyst bed
30°C
40°C
50°C
60°C
1.5–1.7
2.1–2.3
6.2
6.6
10.3
10.6
17.3
17.1
26.0
26.3
height, volumetric feed flow rate ((2–14.8)
×
10–5 L/s),
temperature (30–60 ), initial hydrogen peroxide
°
C
concentration (0.11–2.28 mol/L), initial allyl chloꢀ
ride concentration (1.37–4.86 mol/L), and methanol
concentration (14.03–24.16 mol/L). For assessing the
reproducibility of the measurements, during the
kinetic experiments we perfumed “standard” experiꢀ
ments at intervals in order to ascertain that the activity
of the catalyst had not changed.
fragment is executed by the silicate group and “pushꢀ
ing” is due to the electrophilic peroxide oxygen atom
that results from the abstraction of a water molecule
from species II. The possibility of the formation of an
H2C–O bond at the final stage of the epoxidation proꢀ
cess is ensured by the 1,3ꢀcontact between the carbon
and oxygen atoms forming the oxirane ring.
In view of the foregoing, the following assumptions
were made in constructing the kinetic model of the
process:
From composition data for the reaction mixtures
leaving the reactor. we constructed kinetic curves for
the process. The conventional residence time (
taken to be equal to the ratio of the catalyst weight in
the reactor ( Cat) to the volumetric feed flow rare ( ).
τ
) was
m
F
The kinetics of the process was studied under different
initial conditions and residence times by varying the
rate of feed supply to the reaction zone.
(1) The catalyst surface is uniform.
(2) The adsorption of the initial olefin and water on
the catalyst surface is negligible.
Significant factors in reactions occurring over a
solid catalyst are heat and mass transfers. These factors
come into play and even become crucial when the rate
of the transfer processes is comparable to, or lower
than, the rate of the chemical reaction as such at least
at some stages. For this reason, for obtaining reliable
kinetic data we preliminarily carried out a series of
experiments in order to find the kinetically controlled
region of the epoxidation process and to rule out diffuꢀ
sion limitations.
(3) The target reaction takes place between hydroꢀ
gen peroxide adsorbed on the catalyst surface and disꢀ
solved olefin.
(4) The rateꢀlimiting step is the surface reaction.
(5) The side reactions occur on the catalyst surface.
Thus, the rate of the chemical reactions taking
place in allyl chloride epoxidation with the hydrogen
peroxide solution in the presence of titanium silicalite
in methanol should be described by the following sysꢀ
tem of fractional rational equations:
The effect of internal diffusion limitations was
evaluated in a series of experiments on two catalysts
with different granule sizes of 1.5–1.7 and 2.1–
2.3 mm. The experiments were performed at the same
k1bHPCHPCAC
⎧
r =
,
(1)
(2)
(3)
(4)
1
initial weights of the reaction components (CA0C
=
⎪
⎪
⎪
1 + bHPCHP + bECHCECH
k2bECHCECHCW
0
0
3.49 mol/L,
= 1.16 mol/L,
= 14.95 mol/L,
CM
CHP
r2 =
r3 =
r4 =
,
104 (g s)/L) and four different temperatures
⎪
⎪
1 + bHPCHP + bECHCECH
k3bECHCECHCM
τ
= 1.43
×
⎨
⎪
⎪
⎪
⎪
of 30, 40, 50, and 60°C. The results of these experiꢀ
,
,
ments are presented in Table 2. Under the given experꢀ
imental conditions, passing from the smaller granules
to the larger ones does not affect the hydrogen peroxꢀ
ide conversion, indicating the absence of internal difꢀ
fusion limitations (Table 2). For this reason, all subseꢀ
quent experiments were performed on 2.1–2.3 mm
granules.
To estimating the effect of flow dynamics on the
rate of the process and to exclude external diffusion
limitations, we used the method that had bee sugꢀ
1 + bHPCHP + bECHCECH
k4bHPCHP
⎪
⎩
1 + bHPCHP + bECHCECH
where r1 is the rate of the target reaction (I) (mol s–1 g–1);
r2 r4 are the rates of side reactions (II)–(IV), respecꢀ
tively (mol s–1 g–1); k1 is the rate constant of the target
reaction (L s–1 g–1); k2
k4 are the rate constants of the
–
–
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

KINETICS OF ALLYL CHLORIDE EPOXIDATION
717
–
СHP
–
С
Hydrogen peroxide conversion, %
(
AC)/r1
105, mol s g L–2
×
70
10
8
30
°
C
60
50
40
30
20
10
40
°
C
6
4
50
°
C
60
°
C
2
m
m
Cat = 1.86 g
Cat = 1.05 g
0
0.05
0.15
0.25
HP, mol/L
0.35
0.45
–
C
0
1
2
3
4
5
6
τ × 10–4, g s/L
Fig. 4. Kinetics of the early stages of allyl chloride epoxiꢀ
dation at varied temperatures (CA0C = 4.49–4.86 mol/L,
CH0 P = 0.11–0.39 mol/L,
F = 1.33 × 10 L/s).
–4
Fig. 3. Effects of the conventional residence time (
catalyst weight on the hydrogen peroxide conversion in the
ECH synthesis.
τ
) and
kinetic models suggested here and carried out a priꢀ
mary estimation of the unknown parameters of kinetic
models (1)–(4).
gested by Kafarov [20] and had been widely employed
in similar studies [21, 22]. For this purpose, we carried
out two series of experiments using two different cataꢀ
lyst weights (different catalyst bed heights) at different
volumetric feed flow rates and a constant composition
In the first step of the kinetic study of allyl chloride
epoxidation, we separately investigated the kinetics of
each of the simple reactions (I)–(IV) at low (5–10%)
conversions of the key reactants (hydrogen peroxide in
reactions (I) and (IV) and ECH in reactions (II) and
(III)). When considering the ECH formation reaction
(I), we assumed that there is no hydrogen peroxide
decomposition via reaction (IV). For the reaction
conducted in a differential reactor, which ensures low
hydrogen peroxide conversions, when the product
concentrations can be taken to be zero, Eq. (1) of the
system of kinetic equations (1)–(4) becomes
of the feed entering the reactor (
F
= (2–14.8)
×
10–5 L/s,
CA0C
CH0 P
CM0
= 3.52 mol/L, = 1.17 mol/L,
=
14.93 mol/L). Since temperature variations, which
affect the rate of the chemical reaction, change the
range of conditions in which the reaction is kinetically
controlled [23], these series of experiments were perꢀ
formed at 60°C, the maximum possible temperature.
For each series of experiments, a plot of hydrogen perꢀ
oxide conversion versus conventional contact time
(
ХHP versus ) was constructed from experimental data
τ
(Fig. 3). Clearly, the data obtained in the two series of
experiments fall on one curve with a satisfactory
degree of accuracy. Therefore, the external diffusion
limitations can be neglected under the given experiꢀ
mental conditions, since the hydrogen peroxide conꢀ
version is independent of the feed flow rate. For this
reason, the volumetric feed flow rate in all subsequent
experiments was maintained so that it was not below the
k1bHPCHPCAC
(5)
r =
.
1
1 + bHPCHP
In linearized form, Eq. (5) appears as
CHPCAC
1
1
(6)
=
+
CHP.
r
1
k1bHP k1
In the processes conducted in a differential reactor,
when the conversions of the starting reactants are low,
the reaction rates and reactant concentrations vary
linearly along the catalyst bed height [24]. Under these
conditions, the reaction rates were determined using
the expression presented by Lebedev et al. [23]:
minimum allowable value, which was
5.25
104 (g s)/L) in the case of ECH synthesis. Since
there were no external diffusion limitations at 60
2
×
10–5 L/s (
=
τ
×
°C,
they could be neglected at lower temperatures as well.
According to the recommendations presented in
Ci0XF
the literature [24], the unknown parameters k1–k4
,
(7)
r =
i
.
mCat
In order to estimate the unknown parameters k1
and HP, we performed a series of experiments at varꢀ
b
HP, and ECH of the kinetic model were determined in
b
two steps. In the first step, based on the data obtained
by the reaction isolation method in a differential flow
b
reactor at low (5–10%) conversions of the key reacꢀ ied initial hydrogen peroxide concentrations in excess
tants, we verified that the experimental data fit the allyl chloride in a methanol medium. If Eq. (6) is valid
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

718
SULIMOV et al.
14 + ln
–
СHP
–
С
AC)/rl
105, mol s g L–2
×
k
1[L s–1 g–1
]
(
3.0
2.5
2.0
1.5
1.0
12
30°C
10
8
40
50
60
°
C
6
°
C
4
°
C
2
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
–
C
ECH, mol/L
0.5
0.0028
0.0030
0.0032
0.0034
T
, K–1
1/
Fig. 5. Kinetics of the early stages of allyl chloride epoxiꢀ
dation at varied ECH concentrations and temperatures
(CA0C = 3.31–3.47 mol/L, CH0 P = 1.07–1.13 mol/L, CE0CH
=
Fig. 6. Logarithm of the rate constant versus inverse temꢀ
perature for allyl chloride epoxidation.
–4
0.18–0.80 mol/L,
F = 1.33 × 10 L/s).
cept of the lines. According to Fig. 5, bECH
where is the slope candle of the straight lines.
The temperature dependences of the rate constant
k1 and adsorption coefficients HP and ECH were estiꢀ
mated using the Arrhenius and van’t Hoff equations,
respectively. The temperatureꢀdependent experimenꢀ
tal data in linearized form are presented in Figs. 6 and
7. From these temperature dependences, we estimated
the corresponding parameters, whose numerical valꢀ
ues are listed in Table 3 (row 1).
In a similar way, we investigated the kinetics of side
reactions (II)–(IV). The results og mathematical proꢀ
cessing of the relevant data are presented in Table 3.
Thus, we obtained a primary estimate of the kinetic
equations that describe the early stages of allyl chloꢀ
=
k
1tan
β
,
for the kinetics of the early stages of allyl chloride
epoxidation, the and values obtained and the
corresponding values of the rate r1 determined via
Eq. (7) at a constant temperature will fall on one
straight line in the coordinates of this equation,
β
CHP
CAC
b
b
Figure 4 presents experimental
CHPCAC r = f (CHP).
1
data fitted to Eq. (6). Clearly, the calculated values
fall on one straight line with a satisfactory degree
of accuracy. The mean relative deviation here is
2.11%.
For estimating the ECH effect on the epoxidation
kinetics and for finding the parameter bECH, we carried
out a series of experiments at fixed amounts of allyl
chloride and hydrogen peroxide and varied amounts of
ECH. Under these conditions, the kinetics of the
ECH formation reaction is described by Eq. (1).
In linearized form, Eq. (1) appears as
2 + ln
1.9
b
i [L mol–1
]
CHPCAC 1 + bHPCHP bECH
(8)
=
+
CECH.
r
k1bHP
If Eq. (8) is valid for the kinetics of the early stages
of epoxidation, the and values obtained
k1bHP
1
1.6
1.3
1.0
0.7
C
HP, CAC
,
CECH
and the corresponding values of the rate r1 determined
via Eq. (7) at a constant temperature will fall on one
straight line in the coordinates of Eq. (8),
1
2
Figure 5 presents the correꢀ
CHPCAC r = f (CECH).
1
sponding experimental data in these coordinates.
Clearly, the deviation from linearity is small: the mean
relative deviation is 1.61%.
0.0028
0.0030
0.0032
0.0034
T
, K–1
1/
From the data presented in Figs. 4 and 5, we calcuꢀ
lated the parameters of kinetic equation (1),
namely,k1
1 = 1/tan
angle of the straight lines and
,
b
α
HP, and
bECH. It follows from Fig. 4 that
Fig. 7. Logarithm of the adsorption coefficients of (
1)
k
and HP = tan
b
α
/L, where
α
is the slope
ECCH and ( ) hydrogen peroxide versus inverse temperaꢀ
2
L
is the ordinate interꢀ
ture for allyl chloride epoxidation.
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

KINETICS OF ALLYL CHLORIDE EPOXIDATION
i, mol/L
719
CHP
,
СECH, mol/L
C
CMP CPD
1.0
0.14
0.12
0.10
0.08
0.06
0.04
0.02
,
,
,
—40
—50
—60
°C
°C
°C
0.8
0.6
0.4
0.2
HP ECH
,
,
,
,
—30
—40
—50
—60
°C
°C
°C
°C
0
50
100
150
200
250
300
τ × 10–4, г с/л
0
50
100
150
200
250
300
τ × 10–4, g s/L
Fig. 8. Hydrogen peroxide and ECH concentrations as a
function of conventional residence time at different temꢀ
peratures (CA0C = 3.03 mol/L, CA0C CH0 P = 3 mol/mol,
Cat
Fig. 9. Concentrations of side products of the allyl chloride
epoxidation process as a function of conventional resiꢀ
m
= 18.26 g).
dence time at different temperatures (CA0C = 3.03 mol/L,
CA0C CH0 P = 3 mol/mol,
m
= 18.26 g).
Cat
ride epoxidation and accompanying side reactions.
The consistency of the data presented in Table 3,
which were obtained by independent investigation of
separate reactions, is evidence that the above
assumptions are valid and the calculated parameꢀ
ters are true.
our study we carried several series of experiments
under varied initial conditions and varied convenꢀ
tional residence times. The data obtained in these
experiments were mathematically processed to refine
the process parameters. The earlier determined rate
constants (Table 3) were used as the initial estimates of
the corresponding parameters. The kinetic equations
were integrated by the modified Euler method with a
In order to refine the parameters of kinetic model
(1)–(4) and, most importantly, to see whether this
model can be used to describe the allyl chloride epoxiꢀ
dation process up to high hydrogen peroxide converꢀ
sions in the integral flow reactor, in the second step of variable integration step. The constants of the kinetic
Table 3. Parameters of the Arrhenius and van’t Hoff equations for allyl chloride epoxidation
b0HP
,
L/mol
b0ECH
, L/mol
0
L s–1 g–1
E
i, J/mol
Q
HP, J/mol
QECH, J/mol
Reaction
ki ,
103
103
103
56.75
70.09
65.20
50.19
×
×
×
×
103
103
103
103
3.03
3.08
3.05
5.70
×
10–4
10–4
10–4
10–4
5.71
4.57
4.79
4.27
×
10–4
10–4
10–4
10–4
19.36
19.56
19.75
19.45
×
×
×
×
103
103
103
103
18.69
×
×
×
×
103
103
103
103
(I)
11.05
5.94
1.10
×
×
×
(II)
×
×
×
×
×
×
17.53
18.58
18.55
(III)
(IV)
5.11
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

720
CHP
SULIMOV et al.
,
СECH, mol/L
C
i, mol/L
0.08
1.5
1.2
0.9
0.6
0.3
CMP CPD СH0 P СA0C
/
,
,
,
,
—2
—3
—4
—5
0.06
0.04
0.02
0
HP AC
0
HPECH
С
/С
,
,
,
,
,
—2
—3
—4
—5
—6
0
50
100 150 200 250 300
τ × 10–4, g s/L
0
100
200
300
τ × 10–4, g s/L
Fig. 10. Hydrogen peroxide and ECH concentrations as
a function of conventional residence time at different
Fig. 11. Concentrations of side products of epoxidation as
a function of conventional residence time at different iniꢀ
initial hydrogen peroxide concentrations (40°C, CA0C
=
tial hydrogen peroxide concentrations (40°C, CA0C
=
3.03 mol/L, = 18.26 g).
m
3.03 mol/L, = 18.26 g).
m
Cat
Cat
Ci, mol/L
CHP, СECH, mol/L
0.05
CMP CPD СH0 P
/
СA0C
0.6
,
,
,
—2
—3
—4
0.04
0.03
0.02
0.01
0
0
HPECH
С
/С
AC
, —2HP
0.4
0.2
—
—
—
3
4
5
,
,
,
,
—
6
0
50
100
150
200
250
τ × 10–4, g s/L
300
0
50
100
150
200
250
τ × 10–4, g s/L
300
Fig. 12. Hydrogen peroxide and ECH concentrations as a
function of conventional residence time at different initial
Fig. 13. Concentrations of side products of epoxidation
as a function of conventional residence time at differꢀ
allyl chloride concentrations (40°C, CH0 P = 0.685 mol/L,
Cat
ent initial allyl chloride concentrations (40°C, CH0 P
=
m
= 18.26 g).
0.685 mol/L, = 18.26 g).
m
Cat
equations were determined using Newton’s nonlinear able factors at different hydrogen peroxide conversions
(Figs. 8–13).
method by minimizing the sum of the squares of the
deviations between the calculated and experimental
concentration values. The results of this mathematical
data processing are presented in Table 4.
As follows from Figs. 8–13, the calculated and
experimental data are in good agreement. Therefore,
kinetic model (1)–(4) is fully adequate to the real proꢀ
cess and confirms the mechanism suggested for liquidꢀ
phase allyl chloride epoxidation with aqueous hydroꢀ
gen peroxide in the presence of titanium silicalite. The
results of this study can be of use in engineering calcuꢀ
lations for tubular allyl chloride epoxidation reacꢀ
Statistical processing of the kinetic model using
Fisher’s test demonstrated that, at a significance level
of 0.05, the model adequately describes the experiꢀ
mental data and provides means to predict the compoꢀ
sition of the reaction mixture in a wide range of variꢀ tors and in further process optimization using
KINETICS AND CATALYSIS Vol. 55
No. 6 2014

KINETICS OF ALLYL CHLORIDE EPOXIDATION
721
Table 4. Kinetic parameters of the allyl chloride epoxida
tion process
3. Khlororganicheskie produkty: Spravochnik fizikoꢀ
khimicheskikh velichin (Chlorinated Organics: A
Handbook of Physical and Chemical Data), Mosꢀ
cow: MITKhT, 2013.
Parameter
k01, L s–1 g–1
Value
(11.06 0.51)
(1.12 0.06)
(6.71 0.35)
12.93 0.58
4. Epicerol Process: Growing Green, Brussels: Solvay
Chemicals, 2008.
5. Dmitriev, G.S. and Zanaveskin, L.N., Khim. Prom–st.
Segodnya, 2012, no. 3, p. 8.
×
×
×
103
103
103
k02, L s–1 g–1
k03, L s–1 g–1
k04, L s–1 g–1
6. Gao, H., Lu, G., Suo, J., and Li, S., Appl. Catal., A
1996, vol. 138, no. 1, p. 27.
,
7. Kumar, R.P. and Kumar, R., Catal. Commun., 2007,
no. 8, p. 379.
8. US Patent 5965754, 1999.
9. US Patent 2001020105, 2001.
10. Xia, H., Zhou, C.ꢀH., Tong, D., Chen, J., Yu, W., and
Liu, S., Appl. Clay Sci., 2011, vol. 53, p. 279.
11. Li, W., Ying, Z., and Zhentao, M., J. Chem. Technol.
Biotechnol., 2007, vol. 82, p. 414.
(55.0 1.8)
(66.0 4.5)
(70.6 3.0)
(50.0 2.6)
×
103
103
103
103
E
E
E
E
1, J/mol
2, J/mol
3, J/mol
4, J/mol
×
×
×
12. RF Patent 2422360, 2011.
13. Danov, S.M., Sulimov, A.V., Kolesnikov, V.A., and
Ovcharov, A.A., Kinet. Catal., 2013, vol. 54, no. 2,
p. 193.
14. US Patent 4410501, 1983.
15. Clerici, M.G., Bellussi, G., and Romano, U., J. Catal.
1991, vol. 129, no. 1, p. 159.
16. Sulimov, A.V., Danov, S.M., and Ovcharova, A.V., Russ.
J. Appl. Chem., 2009, vol. 82, no. 11, p. 1991.
,
b0HP
,
L/mol;
(3.06 0.15)
(4.59 0.15)
×
×
10–4
10–4
b0ECH
,
L/mol
17. Schumb, W.C., Satterfield, C.N., and Ventworth, R.L.,
Hydrogen Peroxide, New York: Reinhold, 1955.
103
103
Q
Q
HP, J/mol
(19.4 0.9)
(18.0 0.7)
×
18. Danov, S.M., Sulimov, A.V., Kolesnikov, V.A., and
Ovcharova, A.V., Kinet. Catal., 2011, vol. 52, no. 6,
p. 793.
ECH, J/mol
×
19. Luchinskii, G.P., Khimiya titana (Titanium Chemisꢀ
try), Moscow: Khimiya, 1971.
20. Kafarov, V.V., Metody kibernetiki v khimii i khimicheskoi
tekhnologii (Methods of Cybernetics in Chemistry and
Chemical Engineering), Moscow: Khimiya, 1985.
computer modeling of chemical technological sysꢀ
tems.
21. Bottino, A., Capannelli, G., and Comite, A., Chem.
Eng. J., 2003, vol. 94, no. 1, p. 11.
ACKNOWLEDGMENTS
22. Sridevi, U., Bhaskar Rao, B.K., and Pradhan, N.C.,
This work was supported by the Ministry of Educaꢀ
tion and Science of the Russian Federation (grant
agreement no. 14.577.21.0093).
Chem. Eng. J., 2001, vol. 83, no. 3, p. 185.
23. Lebedev, N.N., Manakov, M.N., and Shvets, V.F., Teorꢀ
iya khimicheskikh protsessov osnovnogo organicheskogo i
neftekhimicheskogo sinteza (Theory of Chemical Proꢀ
cesses in Bulk Organic and Petrochemical Syntheses),
Moscow: Khimiya, 1984.
REFERENCES
24. Zhorov, Yu.M., Kinetika promyshlennykh organꢀ
icheskikh reaktsii (Kinetics of Industrially Important
Organic Reactions), Moscow: Khimiya, 1989.
1. Epichlorohydrin: production and market survey, Evraz.
Khim. Rynok, 2010, no. 3, p. 63.
2. Paken, A.M., Epoksidnye soedineniya i epoksidnye
smoly (Epoxides and Epoxy Resins), Leningrad: Goskꢀ
himizdat, 1962.
Translated by D. Zvukov
KINETICS AND CATALYSIS Vol. 55
No. 6 2014