ISSN 0965ꢀ5441, Petroleum Chemistry, 2012, Vol. 52, No. 6, pp. 426–431. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © A.V. Balaev, N.F. Grigor’eva, A.N. Khazipova, B.I. Kutepov, U.M. Dzhemilev, 2012, published in Neftekhimiya, 2012, Vol. 52, No. 6, pp. 459–464.
A Kinetic Model of the Dimerization of αꢀMethylstyrene
in the Presence of HighꢀSilica Zeolite Y
A. V. Balaev, N. F. Grigor’eva, A. N. Khazipova, B. I. Kutepov, and U. M. Dzhemilev
Institute of Petroleum Chemistry and Catalysis, Russian Academy of Sciences, Ufa, Russia
eꢀmail: nggꢀink@mail.ru
Received October 11, 2011
Abstract—The kinetics of the dimerization of ꢀmethylstyrene in the presence of highꢀsilica zeolite HNaY
α
has been studied, and a nineꢀstage scheme of the monomer conversion has been developed. Analysis of the
kinetic models developed in the form of the Langmuir–Hinshelwood relationships and in terms of the mass
action law has shown that the first model more adequately describes the experimental data. The numerical
values of kinetic and adsorption parameters are represented.
DOI: 10.1134/S0965544112060047
The development of effective methods for producꢀ
ing linear dimers of ꢀmethylstyrene (4ꢀmethylꢀ2,4ꢀ ing an industrial process is the knowledge of its kinetic
It is known that a necessary condition for calculatꢀ
α
diphenylpentꢀ1ꢀ and ꢀ2ꢀenes) has been given constant model [16–17]. Therefore, the aim of the study was to
attention in the literature, because the application analyze the kinetics of the dimerization of AMS in the
ranges of these compounds are very diverse: molecular presence of the Y zeolite (SiO2/Al2O3 = 6.0) and to
weight regulators for polymers, solvents, components develop a kinetic model of the process.
of synthetic lubricants, plasticizers of polymers and
rubbers, and radiationꢀresistant heatꢀtransfer agents
[1–5].
EXPERIMENTAL
A NaY zeolite with a molar ratio of SiO2/Al2O3
=
The synthesis of dimers of
α
ꢀmethylstyrene (AMS)
6.0 synthesized by the technique described in [18] was
used. A HNaY zeolite with the degree of Nа+ Н+ ion
exchange of 53 wt % (0.53НNaY6.0) was prepared by
decationation. The purity of the used AMS was 99.8%.
To study the conversion of individual dimers, 4ꢀ
in the presence of different acid catalysts has been
described in a large number of studies [6–14]. At the
same time, a detailed kinetic study of the reaction is
almost absent, except for [13], where the dimerization
of AMS in the presence of cationꢀexchange resins has
been studied in an environment of different solvents
(cumene, anisole, phenol, substituted phenols), and
[14] concerned with dimerization in an environment
of ionic liquids. However, the analysis of the kinetics
carried out in the mentioned studies is largely qualitaꢀ
tive. There are no kinetic equations for the product
formation rates; a mathematical processing of the
experimental data has not been performed; therefore,
it is impossible to quantitatively estimate the reaction
rate.
methylꢀ2,4ꢀdiphenylpentꢀ1ꢀene (
rial concentration of 98.5% and 1,1,3ꢀtrimethylꢀ3ꢀ
1
) with a base mateꢀ
phenylindane (2) with a purity of 99.8% were isolated
and used.
Kinetic experiments were performed in a batch
thermostated reactor at atmospheric pressure. AMS
was heated in the reactor to a desired temperature, and
then the catalyst was charged. Samples for analysis
were taken at regular intervals. The stirrer speed was
800–1200 rpm to provide the occurrence of the reacꢀ
tion in the kinetic region. During the experiments, the
We have previously developed [15] a kinetic model
of the dimerization of AMS in the presence of a Y zeoꢀ
lite (SiO2/Al2O3 = 5.2), which provides the synthesis
of AMS linear dimers with a selectivity of 90–92% at
a monomer conversion of 100%. At present, a method
temperature was varied in a range of 60–100 С; the
°
catalyst content, 2–20 wt %; and the experiment time,
1–6 h.
The quantitative composition of the reaction prodꢀ
ucts was determined by GLC using a Carlo Erba
for producing a highꢀsilica Y zeolite (SiO2/Al2O3
=
6.0), which does not require a dealumination phase, HRGS 5300 Mega chromatograph with a FID and a
has been assimilated in Salavatnefteorgsintez. This 25ꢀm glass capillary column and SEꢀ30 as a phase.
catalyst is much more resistant to high temperatures Conditions of analysis: a temperature program of 50 to
(up to 800
decationation; therefore, it can be recommended for ature of 250
industrial implementation. helium as a carrier gas, 30 mL/min. The products were
°
С) and is not destroyed at high degrees of 280
°
С
at a rate of rise of
8 C/min; a detector temperꢀ
°
°
С; an evaporator temperature of 300
°
С;
426