1070-4272/01/7408-1318 $25.00 C 2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 8, 2001, pp. 1318!1320. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 8, 2001,
Original Russian Text Copyright + 2001 by Il’chibaeva, Kagan, Tomilov.
AND ION-EXCHANGE PROCESSES
Electrochemical Methoxylation of Styrene
with Gas-Lift in Continuous Mode
I. B. Il’chibaeva, E. Sh. Kagan, and A. P. Tomilov
Southern-Russia State Technical University, Novocherkassk, Russia
State Research Institute of Organic Chemistry and Technology, Moscow, Russia
Received February 14, 2001
Abstract-Anodic oxidation of styrene in methanol was performed in an electrolyzer with gas-lift. The pos-
sibility of carrying this process out in continuous mode with the use of technical-grade methanol was studied.
Recently, the reaction of styrene methoxylation,
making possible manufacture of a number of impor-
tant organic preparations, e.g., benzaldehyde and anis-
aldehyde, has been studied intensively. Electrochem-
ical methoxylation of styrene (I) leads to formation of
1,2-dimethoxyethylbenzene (II) with subsequent splitt-
ing of the C3C bond and conversion of II into di-
methylacetal of benzaldehyde (III):
A number of studies have been concerned with
the effect of a supporting electrolyte, anode material,
and other factors on the yield of the reaction products
. It was established that conversion of styrene I
into 1,2-dimethoxyethylbenzene II is the most ef-
ficient in electrolysis with a platinum anode and po-
tassium fluoride solution as supporting electrolyte.
The conditions were described under which the yield
of compound III is as high as 66%, and the current
efficiency, 33%, after passing 8 F of electricity per
1 mol of styrene.
All the experiments described in the literature have
been performed in a diaphragmless glass electrolyzer
equipped with magnetic stirrer for solution agitation.
Such an electrolyzer cannot serve as a prototype of
an industrial apparatus.
In the industry, the best-developed design is the
electrolyzer of filter-press type in which the electro-
lyte circulation is effected by gases formed in elec-
trolysis-the gas-lift system . Electrolyzers of this
kind exhibit good performance in electrolysis of wa-
ter. It has been shown that cathodic hydrodimerization
of acetone can be performed in an electrolyzer with
gas-lift system .
Electrochemical synthesis of compound III is of
practical importance. In view of this fact, the present
study was aimed at verifying the possibility of carry-
ing out the given reaction in a prototype industrial
electrolyzer. In order to create conditions as close
as possible to those used in the industry, the process
was performed in continuous mode with the use of
technical-grade methanol [GOST (State Standard)
2222395] as solvent.
The experiments were carried in electrolyzer 1 (see
figure) in the form of a glass cylinder 55 mm in diam-
eter and 140 mm high. An electrode pack compris-