Codimerisation of styrene and α-methylstyrene in the presence of zeolites

Article abstract of DOI:10.1016/j.apcata.2011.08.025

The reaction of styrene with α-methylstyrene has been studied over Y, Beta and ZSM-12 zeolites at 80-120 °C in the presence or absence of chlorobenzene. Homo- and codimers of styrene and α-methylstyrene were the main reaction products. The yield of dimers

Full text of DOI:10.1016/j.apcata.2011.08.025

Applied Catalysis A: General 407 (2011) 85–90
Contents lists available at SciVerse ScienceDirect
Applied Catalysis A: General
journal homepage: www.elsevier.com/locate/apcata
Codimerisation of styrene and ␣-methylstyrene in the presence of zeolites
N.G. Grigor’eva∗, S.V. Bubennov, L.M. Khalilov, B.I. Kutepov
Institute of Petrochemistry and Catalysis, Russian Academy of Sciences, 141 prosp. Oktyabrya, 450075 Ufa, Russian Federation
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 23 May 2011
Received in revised form 16 August 2011
Accepted 17 August 2011
Available online 27 August 2011
The reaction of styrene with ␣-methylstyrene has been studied over Y, Beta and ZSM-12 zeolites
at 80–120 ◦C in the presence or absence of chlorobenzene. Homo- and codimers of styrene and ␣-
methylstyrene were the main reaction products. The yield of dimers and their structure depends on
zeolite type and the experimental conditions. Dimers were formed with greater selectively over zeolite
HZSM-12 (S = 80–83%), for which the structural features promote the synthesis of linear compounds. In
the presence of the zeolites HY and HBeta, cyclic homo- and codimers were the predominant products.
The yield of dimers increases with increased reaction temperature and catalyst concentration, and in
the presence of solvent. All zeolites investigated showed high codimerisation activity on styrene and
␣-methylstyrene at 120 ◦C.
Keywords:
Codimerisation
Styrene
␣-Methylstyrene
Homo-dimers
Codimers
© 2011 Elsevier B.V. All rights reserved.
Zeolites
1. Introduction
the presence of Y zeolites with a degree of proton exchange of
10% (55 wt.% of the catalyst, concentration of styrene in CH2Cl2,
Linear dimers of ␣-methylstyrene are used as polymer and rub-
ber molecular-weight regulators and plasticisers, and employed
in dielectric liquids and solvents [1–4]. High-performance lubri-
cating materials are manufactured from hydrogenated dimers [2].
Fuel and radiation-resistant heat-transfers fluids and monomers,
used in the synthesis of gas-separation membranes, are produced
from cyclic dimer of ␣-methylstyrene [5,6]. Styrene dimers are
promising as components of epoxide resins, varnishes, paints, and
polyvinylchloride materials [7–10].
The catalytic homodimerisation of styrene and ␣-methylstyrene
proceeds, depending on the nature of the catalyst and the reaction
conditions, to form dimers with linear (1a; 1b, 2a) or cyclic (1c;
2b,c) structures (Scheme 1) [11,12].
0,2 mol l−1, 25 ◦C) [13]. The cyclic dimers of styrene-cis- and trans-
1-methyl-3-phenylindane were obtained with a selectivity of
84–90% on zeolite Beta (500–1000 wt.% of the catalyst, concentra-
tion of styrene in CCl4 0.02 mol l−1) [14]. The zeolite-like crystalline
aluminophosphates AlPO4-8 exhibited a high activity in dimerisa-
tion of ␣-methylstyrene [15]. The transformation is characterised
by a high conversion of the monomer (97%) with selectivity of linear
dimers of ␣-methylstyrene (4-methyl-2,4-diphenylpent-1- and -2-
enes) 94% in the presence of these catalysts under mild conditions
(p = 0.1 MPa, T = 75–100 ◦C).
Analogous results were obtained while studying of ␣-
methylstyrene linear dimerisation in the presence of zeolites of Y,
Beta, ZSM-12 [16–22].
Large pore zeolites and zeolite-like materials have been shown
to exhibit high efficiency in the homodimerisation of vinylarenes
[13–22].
In contrast to the wealth of detailed studies on the dimerisation
of individual monomers, the codimerisation of styrene and ␣-
methylstyrene has not been thoroughly investigated. Styrene and
␣-methylstyrene codimerisation in the presence of phosphoric acid
has been reported; the conditions led to a mixture of cyclic homo-
and codimers. The synthesis was carried out at 130–155 ◦C using
phosphoric acid, which was concentrated through evaporation
(until the boiling point 200–220 ◦C), and a mixture of monomers
(monomers:Н3РO4 = 1:2, w/w) [23]. We chose, instead, to study
styrene/␣-methylstyrene codimerisation using heterogeneous cat-
alysts.
These zeolites contain 12-ring or 14-ring Si–O–Al–, which form
entrance windows into the channels or cavities of zeolites. Wide
pores provide access for reagent molecules to acidic catalytic sites
and allow transport of the reaction products from zeolite channels.
The regioselectivity of the formation of preferentially linear
dimers or cyclic dimers depends on both structure of zeolite
and its acidic characteristics. The linear dimer of styrene-1,3-
diphenylbut-1-ene was synthesised with a selectivity of 81% in
The successful synthesis of homodimers of styrene and ␣-
methylstyrene in the presence of zeolite catalysts lead us to assume
that zeolites may also be useful in the production of vinylarene
codimers mentioned above.
∗
Corresponding author. Tel.: +7 347 2 84 27 50; fax: +7 347 2 84 27 50.
E-mail address: ngg-ink@mail.ru (N.G. Grigor’eva).
0926-860X/$ – see front matter © 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.apcata.2011.08.025

86
N.G. Grigor’eva et al. / Applied Catalysis A: General 407 (2011) 85–90
2.3. Cooligomerisation of vinylarenes
Nomenclature
Cooligomerisation was carried out in a isothermal batch reactor
in the presence of 5–20 wt.% of catalyst (calculated on mixture of
vinylarenes), at 80–130 ◦C, in the presence or absence of chloroben-
zene. After the completion of the reaction, the reaction mass was
separated from the catalyst by filtration. The conversion of ini-
tial vinylarenes and the quantitative composition of the dimer
fraction were determined using gas-liquid chromatography (GLC).
The composition of the oligomers formed was analysed using
high-performance liquid chromatography (HPLC). For calibration,
dimers and trimers were isolated with vacuum distillation.
Homodimers of styrene and ␣-methylstyrene (1, 2) were iden-
tified using presynthesised compounds [25,26]. The chemical
structure of codimers (3, 4, 6) was established by means of GC/MS
and NMR spectroscopy; linear codimers (5) were identified using
GC/MS-spectrometry.
␣-ms
CD
CCD
LCD
LD
[M0]
MWD
St
␣-methylstyrene
cyclic dimer
cyclic codimer of styrene and ␣-methylstyrene
linear codimer of styrene and ␣-methylstyrene
linear dimer
initial vinylarenes concentration in chlorbenzene
molecular-weight distribution
styrene
T
temperature
This study of the reaction of styrene and ␣-methylstyrene in
the presence of the large-pore zeolites Y and Beta and medium-
pore ZSM-12 will help develop a low-waste method of vinylarene
cooligomerisation.
2.3.1. Synthesis of trans-3-methyl-1,3-diphenylbut-1-ene and
2,4-diphenylpent-1-ene (Scheme 2)
2. Experimental
Zeolite НZSM-12 (1.1 g) was added to a mixture of styrene (5.2 g,
5 mmol) and ␣-methylstyrene (5.9 g, 5 mmol) in chlorobenzene
(25 ml) at 100 ◦C and stirred for 5 h. After cooling, the catalyst was
filtered from the reaction mixture and solvent, and unreacted viny-
larenes were removed at reduced pressure. Dimer fractions (8.5 g)
(120–135 ◦C/2 mm Hg) were isolated through distillation of the
reaction mixture (dimers – 82.2%, trimers and higher molecules
– 17.8%). Cyclic dimers 1c, 6 (60%) were separated by means of
recrystallisation of dimer fractions from ethanol. The concentrate
of linear homo- and codimers was distilled under vacuum. The
fraction with the highest linear codimer content (1,3-diphenylbut-
1-ene 2a (11.7%); 4-methyl-2,4-diphenylpent-1-ene 1a (7.7%);
4-methyl-2,4-diphenylpent-2-ene 1b (30.8%); 3 (21.5%); 4 (28.3%)
was analysed using 1Н and 13C NMR.
2.1. Chemicals and materials
Rectified styrene (public corporation “Salavatnefteorgsyn-
tez”, 99.9%), ␣-methylstyrene (public corporation “Ufaorgsyntez”,
99.8%) and chlorobenzene (Acros Chemicals, 99.9%) were used.
2.2. Catalysts
Zeolite Y, with a SiO2/Al2O3 ratio = 6.0, was synthesised in the
Na-form by a previously described technique [24]. Zeolite NаY was
transformed into the H-form (exchange degree of ions Nа+ on Н+
was 96%) by decationation from a solution of NН4NO3 in three
stages and by intermediate calcination at 540 ◦C. Zeolites NН4-Beta
(BEA) and Н-ZSM-12 (MTW) were produced by the public corpo-
ration Angarsk Factory of Catalysts and Organic Synthesis. Zeolite
NН4-Beta was transferred into H-form by calcination at 540 ◦C for
4 h. Catalyst characteristics are collected in Table 1, FTIR-spectra in
Fig. 1. The FTIR-spectra were recorded at the Boreskov Institute of
Catalysis, Siberian Division, Russian Academy of Sciences. Catalyst
samples were calcined at 540 ◦C for 4 h before all experiments.
trans-3-Methyl-1,3-diphenylbut-1-ene (3). 1H NMR, ı: 1.70 (6
H, s, 2CH3), 6.60–6.65 (2H, m, J = 10, CH CH), 7.0–7.6 (10H, m, ArH);
13C NMR, ı: 28.89 (CH3), 40.94 (CH), 126.09 ( CH), 140.30 ( CH);
121.91–148.73 (Ar); m/z: 222; Kovaè index Ik 1820
2,4-Diphenylpent-2-ene (4). 1H NMR, ı: 1.60 (3H, d, J 7.0, CH3,),
2.26 (3H, s, CH3), 4.03 (1H, m, CH), 6.11 (1H, d, CH), 6.95-7.43
(10H, m, ArH); 13C NMR, ı: 16.26 (CH3), 22.61 (CH3), 38.47 (CH),
Scheme 1. Homo-dimerisation of styrene and ␣-methylstyrene.
Table 1
Characteristics of zeolites.
Catalyst
SiO2/Al2O3 ratio
Degree of exchange of Na+ for H+ (%)
Degree of crystallinity (%)
Acid properties
N
H, (␮mol g−1
)
PA (kJ mol−1
)
References
[18]
H
O
Si
Al
)
320 (
1170
1220
1265
1165
1165
60 (AlOH)
73 (AlOH)
179
Y
6
96
100
Beta
ZSM-12
18
34
98
98
99
100
[19]
[19]
106

N.G. Grigor’eva et al. / Applied Catalysis A: General 407 (2011) 85–90
87
Fig. 1. The FTIR-spectra of zeolites Beta, ZSM-12(a) and zeolite Y(b).
133.59 (HC ), 143.83 ( C), 121.91-148.73 (Ar); m/z: 222 (M+);
Kovaè index Ik 1830.
zene (25 ml) at 130 ◦C and stirred for 5 h. After cooling, the
catalyst was filtered, and the solvent was removed at the
reduced pressure. The dimer fractions (7.8 g) (120–135 ◦C/2 mm
Hg) were isolated under vacuum. The mixture of cyclic dimers
was obtained by crystallisation from hexane. The composition of
this mixture was (% w/w): 6–(76.4%); cis- and trans-1-methyl-
3-phenylindane 2b, 2c (1.1%); 1,1,3-trimethyl-3-phenylindane 1c
2,4-Diphenylpent-1-ene (5). m/z: 222; Kovaè index Ik 1746.
2.3.2. Synthesis of 1,1-dimethyl-3-phenylindane
The zeolite HBeta (2.2 g) was added to a mixture of styrene
(5.2 g, 5 mmol) and ␣-methylstyrene (5.9 g, 5 mmol) in chloroben-
Scheme 2. Formation of codimers of styrene and ␣-methylstyrene.

88
N.G. Grigor’eva et al. / Applied Catalysis A: General 407 (2011) 85–90
Table 2
(22.5%). Compound 6 was identified in the mixture by means of
NMR-spectroscopy.
The codimerisation of styrene and ␣-methylstyrene over zeolites Y, Beta,
ZSM-12 (10 wt.% of catalyst; T = 120 ◦C; chlorobenzene; [M0] = 4 mol l−1; styrene:␣-
methylstyrene = 1; reaction time = 5 h).
1,1-Dimethyl-3-phenylindane (6). 1H NMR, ı: 1.32 (3H, s, CH3),
1.48 (3H, s, CH3), 1.79 (1H, m, CH2), 2.04 (1H, m, CH2), 4.47 (1H, tr,
CH), 6.95–7.43 (H, m, ArH); 13C NMR, ı: 28.70 (CH3), 29.10 (CH3),
46.65 (C(CH3)2), 49.04 (CPh), 52.79 (CH2), 121.91–148.73 (Ar); m/z:
222; Kovaè index Ik 1713.
Catalyst
Y
Beta
ZSM-12
Conversion (%)
St
␣-ms
84.0
99.7
88.0
95.1
87.4
95.1
2.4. Analysis
Selectivity (%)
n = 2
62.6
18.7
9.6
77.8
18.0
3.6
83.4
11.1
3.9
1H and 13C NMR spectra were collected on a Bruker AVANCE 400
spectrometer, (1H, 400.13 MHz; 13C, 100.62 MHz, Me4Si) in CDCl3.
High-resolution mass spectra were measured on a Fisons Trio 1000
instrument equipped with a DB-560 quartz column (50 m); the
temperature of the column was increased from 50 to 320 ◦C with
a programmed heating rate of 4 ◦C min−1; the electron impact was
70 eV. GLC analysis was carried out on a HRGS 5300 Mega Series
chromatograph (Carlo Erba) with a flame-ionisation detector. A 25-
m capillary column, SE-30 phase, with temperature-programmed
heating from 50 to 280 ◦C at a rate of 8 ◦C min−1, detector temper-
ature of 250 ◦C, evaporator temperature of 300 ◦C, and helium as a
carrier gas with a flow rate of 30 ml min−1 was used. High-pressure
liquid chromatography analysis was carried out on a HP-1090
n = 3
n = 4
n = 5
9.1a
0.6
1.6
Composition of dimers (%)
Codimers
CD
LD
33.2
8.1
35.4
19.4
20.3
19.3
Dimers of styrene
CD
LD
8.0
8.6
8.4
11.7
3.9
13.7
Dimers of ␣-methylstyrene
CD
LD
11.7
30.4
10.3
14.8
7.1
35.7
a
Content of fraction n = 5–8
˚
chromatograph with a refractometric detector and a Plgel 100 A
Only the isomerisation of codimer with an external double bond (5)
into the codimer with an internal double bond (4) was revealed.
The composition of trimers consists of 80–95% cooligomers with
MW 326 (formed from two molecules of styrene and one molecule
of ␣-methylstyrene) and MW 340 (the product of one molecule
of styrene and two molecules of ␣-methylstyrene), 5–15% trimers
of styrene and up to 3% trimers of ␣-methylstyrene, according to
GC/MS spectrometry.
polystyrene column using toluene as an eluent, a toluene flow rate
of 0.8 mL min−1, and a tape of velocity of 1.5 cm min−1
.
The acid properties of the samples were studied by IR spec-
troscopy of adsorbed CO. Before the adsorption of CO, the samples
were evacuated at 450 ◦C for 2 h. The adsorption of CO was per-
formed on samples cooled with liquid nitrogen and pressures from
0.1 to 10 mm Hg. IR spectra were recorded on a Shimadzu 8300
Fourier spectrometer with a resolution of 4 cm−1 and 50 spectral
acquisitions. The concentration of Brønsted sites (NH, ␮mol g−1
)
was determined from the intensity of the absorption band of
adsorbed CO; the strength of Brønsted sites (PA, kJ mol−1) was
determined by the shift of the bands of OH groups upon adsorp-
tion of CO and characterised by the value of PA (proton affinity)
using a known technique [27,28].
3.2. Effect of zeolite structure
The results of the study of the catalytic properties of zeolites
HY, HBeta and HZSM-12 in the reaction of cooligomerisation of
styrene and ␣-methylstyrene are given in Table 2. All zeolites stud-
ied show high activity in the cooligomerisation of styrene and
␣-methylstyrene. The conversion of monomers at 120 ◦C and the
concentration of catalyst equal 10 wt. % reached 84–99.7%. The
composition of oligomers obtained in the presence of zeolite Y
contains compounds formed from two to eight monomers. The
oligomers, obtained in the presence of zeolites Beta and ZSM-12, are
characterised by a low molecular-weight distribution of products
formed from two to five monomers.
Zeolite ZSM-12 enables dimer formation with maximum selec-
tivity, which amounts to 83.4%. In the case of zeolites Beta and Y,
the selectivity for dimers was 77.8% and 62.6%, respectively.
Scheme 1 shows that the composition of the dimer fraction
contains homodimers in addition to codimers of styrene and ␣-
methylstyrene. With zeolite Beta, the yield of codimers is highest
(54.8%). Over zeolites Y and ZSM-12, codimer is produced in 41.3
and 39.6% fractions, respectively. Zeolites Y and Beta generally pro-
mote the formation of cyclic dimer compounds, including codimers.
The maximum quantity of linear homo- and codimer is formed in
the presence of zeolite ZSM-12.
3. Results and discussion
3.1. Products of cooligomerisation of styrene and
˛-methylstyrene
The cooligomerisation of styrene and ␣-methylstyrene over
zeolites proceeds to form predominantly dimers, as well as
higher molecular-weight oligomers composed of three to five
monomers. Linear and cyclic homodimers of styrene (2a–c) and
␣-methylstyrene (1a–c), as well as codimers of initial vinylarenes
(3–6), are identified in the dimers fractions (Scheme 2).
According to Scheme 2, the formation of linear and cyclic
codimers (3,6) occurs during the reaction of a styrene molecule
with a carbocation formed from ␣-methylstyrene, and linear
codimers (4,5) are formed as
a result of the addition ␣-
methylstyrene molecule to a carbocation obtained from styrene.
The formation of linear codimers (3–5) has not previously been
described in the literature. Linear homodimers of styrene and ␣-
methylstyrene are known to be unstable; increased temperature,
catalyst concentration or reaction times promote transformation
into more stable cyclic indane structures [11]. Actually, a decrease
the concentration of compound (3) and increase in the content of
cyclic codimer (6) was observed during the study of the change of
codimer composition over time. At the same time, the conversion
of linear codimers (4,5) into the cyclic dimer (7) does not take place.
The action of zeolites can be explained by differences in acid
properties and the structure of zeolite.
Zeolite Beta has a three-dimensional intersecting channels sys-
tem; two mutually perpendicular straight channels, each with
˚
a cross-section of 7.7 × 6.6 A, run in a- and b-directions, and
˚
a sinusoidal channel of 5.6 × 5.6 A running parallel in the c-
direction. In zeolite ZSM-12, rectilinear channels are also formed
by 12-membered rings with a diameter of the entrance windows

N.G. Grigor’eva et al. / Applied Catalysis A: General 407 (2011) 85–90
89
Table 3
The codimerisation of styrene and ␣-methylstyrene over zeolite Beta in chloroben-
zene or in the absence of solvent (20 wt.% of catalyst, T = 120 ◦C, chlorobenzene,
[M0] = 4 mol l−1, styrene:␣-methylstyrene = 1; reaction time = 3 h).
Solvent
Without solvent
Conversion (%)
St
␣-ms
100.0
98.9
100.0
100.0
Selectivity (%)
n = 2
n = 3
n = 4
n = 5
75.6
20.1
67.2
26.0
6.0
4.3
-
0.8
Composition of dimers (%)
Codimers
CD
LD
40.0
13.9
38.0
3.9
Dimers of styrene
CD
LD
7.4
8.1
15.6
2.6
Dimers of ␣-methylstyrene
CD
LD
29.2
1.4
39.8
0.1
Fig. 2. The effect of the molar ratio of styrene:␣-methylstyrene on the composition
of oligomers (20 wt.% zeolite HY, T = 120 ◦C, chlorobenzene, [M0] = 4 mol l−1, reaction
time = 5 h).
methylstyrene and reached to 97–100% in all experiments. At a
1:10 ratio of styrene: ␣-methylstyrene the total yield of dimer is
74%, but the yield of codimer decreases. The excess of styrene in the
mixture leads to widening of the MWD of oligomers and a consid-
erable decrease in the yield of dimers. The maximum percentage of
codimer was obtained with a 1:1 molar ratio of vinylarenes.
The composition of the oligomers formed by the reaction of
styrene and ␣-methylstyrene in bulk (in the absence of solvent)
differs from that of those formed in the presence of chlorobenzene
(Table 3). Codimerisation in bulk proceeds to form more trimers and
tetramers. When the codimerisation is carried out in chloroben-
zene, the vinylarene concentration in zeolite pores decreases,
thereby reducing the formation of large oligomer molecules (n ≥ 3).
In addition, solvent accelerates the diffusion of the products being
formed into zeolite cavities and canals. This accelerated diffusion
leads to a reduction in the MWD and increases the yield of dimers,
especially linear codimers of styrene and ␣-methylstyrene (3,4).
Fig. 3 demonstrates the effect of temperature and catalyst con-
centration on the conversion of vinylarenes and on the selectivity of
the dimers formed during the reaction. Increasing the temperature
up to 80 ◦C and the catalyst concentration up to 5% decreases the
yield of dimers and increases the yield of higher molecular-weight
compounds.
˚
5.6 × 6.0 A. The three-dimensional framework of zeolite Y is pene-
trated by large and small cavities. The input into large cavities of
the supercage is limited by 12-membered rings with diameter 7.4 A
˚
[29].
The selectivity of homo- and codimer formation is maximal
on zeolite ZSM-12, which possesses the narrowest pores. Selec-
tivity decreases over zeolites Beta and Y, which have larger pore
structures. Additionally, the formation of oligomers with a wide
molecular-weight distribution (MWD) in the presence of zeolite
Y can be explained by the structural features of its framework,
in which the diameter of an entrance window into the supercage
(7.4 A) is less than the diameter of the cavity (12 A) [29]. The size of
the supercage allows formation of oligomers with a diameter that
exceeds the size of the entrance window. This leads to blockage of
acidic sites located in the big cavities so that the reaction can take
place only on the superficial acid sites where there are no spatial
restrictions for growth of molecules of oligomers.
It is known that the acid properties of zeolites can influence the
degree of vinylarene oligomerisation. During the oligomerisation of
styrene, the strength of the acid catalysts promotes the formation of
a narrower MWD of oligomers [30,31]. According to the data from
Table 1, the concentration of Brønsted acid sites in zeolites studied
decreases in the following order: Y > Beta > ZSM-12. The strength of
acid sites of zeolites Beta and ZSM-12 is higher than those for zeolite
Y. Hence, a high yield of dimers in the presence of zeolites Beta and
ZSM-12 can be explained by the presence of stronger Brønsted acid
sites in these catalysts than in zeolite Y.
The results of ␣-methylstyrene dimerisation showed that the
quantity and strength of Brønsted acid sites is an important fac-
tor that defines the ratio of linear and cyclic dimers. The enhanced
strength and quantity of Brønsted acid sites promotes cyclodimeri-
sation of ␣-methylstyrene. Therefore, the codimerisation of styrene
and ␣-methylstyrene in the presence of zeolites Y and Beta, which
possess a higher concentration of Brønsted acid sites than zeolite
ZSM-12, proceeds with a high yield of cyclic homo- and codimers.
˚
˚
As shown in Table 4, the composition of codimers depends not
only on zeolite type, but also on the reaction conditions. Linear
codimer (3) predominates among codimers at the beginning of the
reaction. Gradually, its content decreases as a result of conversion
into a cyclic dimer (6), whose yield thereby increases. The con-
tent of linear codimer (4) increases, apparently as a result of the
Table 4
The composition of codimers styrene and ␣-methylstyrene (chlorobenzene
([M0] = 4 mol l−1)).
Catalyst
Catalyst
loading
(wt.%)
T (◦C)
Reaction
time (h)
Composition of codimers (%)
LD(3)
LD(4)
LD(5)
CD (6)
3.3. Effect of the experimental conditions
Beta
Beta
Beta
Y
ZSM-12
ZSM-12
20
20
20
20
20
8
120
120
120
120
120
100
1
3
5
5
5
5
28.9
20.2
10.8
7.2
36.9
56.3
11.1
11.9
14.3
11.3
12.4
26.2
3.1
2.5
0.7
1.0
2.1
5.4
56.9
65.4
74.2
80.5
48.6
12.1
The effect of molar ratio of the vinylarenes on the composition of
oligomers showed that increasing the fraction of ␣-methylstyrene
promotes a decrease in the yield of oligomers with n > 3 (Fig. 2). The
conversion of vinylarenes did not depend on molar ratio styrene:␣-

90
N.G. Grigor’eva et al. / Applied Catalysis A: General 407 (2011) 85–90
a
100
80
60
40
20
0
b 100
80
60
40
20
0
60
80
100
120
140
0
5
10
15
20
T,ºC
wt. %
Fig. 3. The effect of temperature (a) and amount of catalyst (zeolite ZSM-12) in wt% (b) on the conversion of styrene (•) and ␣-methylstyrene (ꢀ) as well as the selectivity
of the dimers formed (ꢁ) (chlorobenzene solvent, [M0] = 4 mol l−1, reaction time = 5 h) (a) 10 wt.% catalyst, b) T = 120 ◦C.
isomerisation of a different codimer (5). The yield of cyclic codimer
also increases with increased reaction temperature and catalyst
concentration.
[3] Y. Sakata, N. Soga, T. Kunugi, JP Patent 9,227,888 (1997).
[4] T.R. Forbus, M.P. Hagemeister, U.S. Patent 069212 (2006).
[5] Chiu I-Ching, U.S. Patent 0,242,441 (2004).
[6] G. Maier, Angew. Chem., Int. Ed. 37 (1998) 2960–2974.
[7] N.A. Jankovskij, A.V. Tugolukov, V.A. Stepanov, RU Patent 2,142,486 (1999).
[8] N.A. Jankovskij, A.V. Tugolukov, V.A. Stepanov, RU Patent 2,147,022 (2000).
[9] N. Yoshihiro, K. Masahiko, Kawasaki Steel Gito 21 (1989) 349–354.
[10] N. Yoshihiro, K. Masahiko, Kawasaki Steel Techn. Rept. 23 (1990) 65–71.
[11] P.H. Plesch, The Chemistry of Cationic Polymerization Symposium Publications
Division, Pergamon Press, Oxford/London/New York/Paris, 1963.
[12] A.R. Taylor, G.W. Keen, E.J. Eisenbraun, J. Org. Chem. 42 (1977) 3477–3480.
[13] K.B. Yoon, J.L. Lim, J.K. Kochi, J. Mol. Catal. A: Chem. 52 (1989) 375–386.
[14] A. Benito, A. Corma, H. Harcia, J. Primo, Appl. Catal. A: Gen. 116 (1994) 127–135.
[15] Ia.I. Isakov, H.N. Minachev, Tc.Z. Sharf, Petrol. Chem. 38 (1998) 404–438.
[16] A. Fihri, R. Durang, F. di Renzo, F. Fajula, Appl. Catal. B: Environ. 98 (2010)
224–228.
[17] V.P. Talzi, V.P. Doronin, T.P. Sorokina, Russ. J. Appl. Chem. 73 (2000) 787–792.
[18] N.G. Grigor’eva, R.R. Galyautdinova, E.A. Paukshtis, B.I. Kutepov, M.I. Tselutina,
U.M. Dzhemilev, Petrol. Chem. 45 (2005) 419–425.
[19] N.G. Grigor’eva, R.R. Galyautdinova, E.A. Paukshtis, B.I. Kutepov, M.I. Tselutina,
U.M. Dzhemilev, Petrol. Chem. 46 (2006) 332–337.
[20] N.G. Grigor’eva, A.V. Vosmerikov, B.I. Kutepov, U.M. Dzhemilev, Petrol. Chem.
48 (2008) 366–370.
[21] N.G. Grigor’eva, R.R. Talipova, B.I. Kutepov, U.M. Dzhemilev, Petrol. Chem. 49
(2009) 16–22.
[22] N.G. Grigor’eva, R.R. Talipova, B.I. Kutepov, U.M. Dzhemilev, Petrol. Chem. 50
(2010) 129–134.
[23] R.N. Volkov, U.S. Tzibin, V.V. Kuzenkov, Petrol. Chem. 10 (1970) 541–545.
[24] M.L. Pavlov, M.I. Levinbuk et al., RU Pаtent 2,090,502 (1997).
[25] N.G. Grigor’eva, R.R. Talipova, A.V. Vosmerikov, B.I. Kutepov, U.M. Dzhemilev,
Russ. Chem. Bull. Int. Ed. 58 (2009) 59–63.
[26] Y. Kawakami, N. Tolyoshima, T. Ando, Y. Yamashita, Polym. J. Tokyo 13 (1981)
947–953.
[27] E.A. Paukshtis, Stud. Surf. Sci. Catal. 130 (2000) 3231–3236.
[28] E.A. Paukshtis, E.N. Yurchenko, Russ. Chem. Rev. 52 (1983) 242–258.
[29] Ch. Baerlocher, D.H. Olson, Atlas of Zeolite Framework Types, 6th ed., Elsevier,
Amsterdam, 2007.
4. Conclusion
Here, we have shown, for the first time, the codimerisation of
styrene and ␣-methylstyrene in the presence of various zeolite
catalysts.
A high activity was found for large pore zeolites Y and Beta
and for the medium pore zeolite ZSM-12, which possess strong
Brønsted acid sites. The conversion of both monomers in the pres-
ence of 10–20 wt.% catalyst at 120 ◦C was close to 100%. The main
reaction products were oligomers; of these, dimers are prevailed.
The degree of oligomerisation of products and their chemical
structure depends on the zeolites structural type and on the reac-
tion conditions. Dimers were formed with the highest selectivity in
the presence of zeolite ZSM-12 (80–83%). In the case of zeolite Beta
and Y, the selectivity for dimers was 77.8% and 62.6%, respectively.
Linear and cyclic homo- and codimers are present in the dimer
fraction. The structural features of zeolite ZSM-12 promote the for-
mation of mainly linear homo- and codimers. In the presence of
zeolites Beta and Y, mostly cyclic dimers are formed.
Carrying out the reaction in chlorobenzene, with the mol ratio of
styrene and ␣-methylstyrene equal to 1:1, increases the selectivity
for dimers.
References
[30] M. Sawamoto, T. Masuda, H. Nisha, T. Higashimura, J. Polym. Sci. 13 (1975)
279–282.
[31] T. Higashimura, M. Hiza, H. Hasegawa, Macromolecules 12 (1979) 217–222.
[1] Q. Cai, J. Li, F. Bao, Y. Shan, Appl. Catal. A: Gen. 279 (2005) 139–143.
[2] T.R. Forbus, M.P. Hagemeister, E.P. 1,778,607 (2007).