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LEBEDEV et al.
As can be seen, the highest yield of the desired EDCS is
reached when performing the reaction in an ether solution,
which involves the use of large amounts of diethyl ether.
Distillation of the reaction products without filtration
of the reaction mixture makes the process less efficient.
The use of the less active suspension of ethylmagnesium
bromide favors an increase in the contribution of TCS dis-
proportionation and the formation of nonvolatile reaction
products. In all the cases, the use of a high-performance
distillation column is required for separation of the reac-
tion mixture. The ether procedure of organomagnesium
synthesis is quite suitable for the synthesis of EDCS in a
laboratory and for its low-tonnage production.
toclave equipped with a stirrer was charged with 101 g
( mol) of DCS, several drops of Karstedt catalyst, and
ethylene in an amount giving the pressure of 0.6 MPa at
20°С. The mixture was heated over 60°С with stirring
and kept under these conditions until the pressure ceased
to decrease. Then, the autoclave was cooled with liquid
nitrogen, a new portion of ethylene was added, and the
process was continued until the last portion of ethylene
(total amount 22 g, 0.78 mol) was consumed. The reaction
products were analyzed by GLC.
Hydrosilylation of ethylene with trichlorosi-
lane. A 0.5-L flask equipped with a stirrer was charged
with 149 g (1.1 mol) of TCS and several drops of Karstedt
catalyst, after which ethylene was bubbled at 20°С. The
mixture spontaneously warmed up to 37°С. The ethylene
bubbling was continued for 3 h until the ethylene conden-
sation in a trap cooled with liquid nitrogen at the outlet of
the system became persistent. Distillation of the reaction
mixture gave 162 g of ethyltrichlorosilane, bp 99°С.
EXPERIMENTAL
1
The H NMR spectra were recorded on a Bruker
AM-360 spectrometer with the working frequency of
360.14 MHz using СDCl3 as solvent.
GLC analysis of the reaction mixtures was performed
with an LKhM-80 chromatograph using a thermal con-
ductivity detector under the following conditions: vapor-
izer temperature 300°C, detector temperature 300°С,
carrier gas helium, carrier gas flow rate 30 mL min–1,
programmable heating at a rate of 16 deg min–1, 2 m ×
5 mm stainless steel column, stationary phase SE-30,
5% on Chromaton N-AW. The gravimetric content of
substances was determined by normalization without
introducing correction coefficients. The peaks were iden-
tified using reference samples of compounds.
Reaction of chlorosilanes with triethylaluminum.
A steel autoclave was charged in a nitrogen atmosphere
with 100 g of TEA and the corresponding amount of
chlorosilanes (STC or TCS). The reaction mixture was
heated with stirring to the required temperature, kept
at this temperature for the above-indicated time, and
cooled. The products were analyzed by GLC. In some
experiments, 1.5 g of NaCl and/or 150 mL of a mixture
of paraffins С14Н30–С17Н36 was added to the reaction
mixture to shift the equilibria.
Reduction of ethyltrichlorosilane with DIBAH.
Equimolar amounts of ETCS and DIBAH (0.2 or 0.4 mol)
were mixed under nitrogen and gradually heated with stir-
ring to 120°С, with distillation of low-boiling substances
through a descending heat exchanger. The low-boiling
products were analyzed by GLC.
GC–MS analysis was performed with anAgilent Tech-
nologies spectrometer under the following conditions:
250 μm × 20 m capillary column coated with SE-30,
mass-spectrometric detector, carrier gas helium, carrier
gas flow rate 1 mL min–1, programmable heating from
20 (0.5 min) to 300°С at a rate of 16 deg min–1, sample
volume 0.5 μL, flow split ratio 400 : 1. The content of
components was determined from the chromatograms by
percent normalization with respect to peak area.
Alkylation of trichlorosilane with ethylmagne-
sium- bromide. Dry diethyl ether was added to 46.6 g
(2 mol) of magnesium powder in an amount sufficient
for the powder to be fully covered by the solvent. Asolu-
tion of 228.9 g (2.1 mol) of ethyl bromide in ether or in
a mixture of xylenes was added dropwise with stirring at
a rate ensuring uniform boiling of the reaction mixture.
The total amount of the solvents was 0.5 L per mole of
magnesium. After the dropwise addition was complete,
the mixture was refluxed with stirring for an additional
1 h, cooled to 15°С, and transferred by applying nitrogen
pressure into a dropping funnel, from which the mixture
was added in portions to a solution of 243.9 g (1.8 mol)
DCS and TCS were purchased from HORST (main
substance content 99.9%).
In all the cases, the desired ethyldichlorosilane was
isolated by distillation on a column 1 cm in diameter,
60 cm long, packed with glass rings 2 mm in diameter,
with the performance of 10 TP, which ensured obtaining
more than 99% pure product.
Hydrosilylation of ethylene with dichlorosi-
lane. Under cooling with liquid nitrogen, a steel au-
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 87 No. 5 2014