ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 10, pp. 1721 1722.
Pleiades Publishing, Inc., 2006.
Original Russian Text
No. 10, p. 1740.
M.G. Voronkov, S.V. Basenko, R.G. Mirskov, S.N. Adamovich, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79,
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Synthesis of High-Purity Tris(trimethylsilyl) Borate
M. G. Voronkov, S. V. Basenko, R. G. Mirskov, and S. N. Adamovich
Favorskii Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
Irkutsk, Russia
Received June 5, 2006
Abstract A method was developed for synthesis of high-purity tris(trimethylsilyl) borate by reaction of tri-
methylacetoxysilane with powdered boric acid.
DOI: 10.1134/S1070427206100351
Tris(trimethylsilyl) borate B(OSiMe ) (TMSB) is
B(OH)3 + 3MeCOOSiMe3
3MeCOOH.
B(OSiMe3)3
3
3
used as a monomer and comonomer in production of
polyorganyl borosiloxane caoutchoucs for improving
their technical parameters, as a catalyst for polymer-
ization processes, and as an adsorbent of neutrons. It
is recommended as a means of protection of surfaces
subjected to action of an electric arc and as a half-
product in synthesis of silicon-and-boron-containing
compounds [1]. High-purity TMSB has been sug-
gested by the authors for use in the microelectronic
technology for plasmochemical deposition of thin
layers of boron-doped silicon dioxide, with a boron
content of 1.5 to 10 wt % [2].
+
A mixture of 20 g (0.15 mol) of trimethylacetoxy-
silane and 3 g (0.05 mol) of finely ground boric acid
of chemically pure grade was heated at 110 C for 1 h.
After acetic acid was evaporated (8.4 g, 97%), the re-
sidue was distilled in a vacuum. The yield of TMSB
2
0
was 7.95 g (95%), bp 70 C (19 mmHg), n = 1.3865,
d
in agreement with published data [3]: bp 48 C
0
(
5 mm Hg), n2 = 1.3860.
d
According to GLC data, TMSB purified by recti-
fication in a vacuum on a quartz column is free of
even trace amounts of organic impurities. Accord-
ing to the results of an atomic-absorption analysis,
the content of metals (Na, K, Ca, Fe, Ni, Co, etc.)
does not exceed 10 5 10 wt % for each of the me-
tals.
Previously, TMSB has been synthesized in a 20%
2
yield by heating hexamethyldisiloxane with B O3
in an autoclave at 350 C or by boiling trimethyl-
6
chlorosilane with H BO (yield 26.5%) [3].
3
3
The yield of TMSB could be raised to 81% on
heating hexamethyldisilthiane with boric acid to
20 C [4]. However, use of the difficultly acces-
CONCLUSION
1
sible and foul-smelling hexamethyldisilthiane is un-
feasible for industry. The reaction of hexamethyl-
disilazane with ammonium borate in a solvent [5]
or with boric acid at 110 120 C in the course of
A method for synthesis of high-purity tris(trimeth-
ylsilyl) borate for micro- and optoelectronics in a 92%
yield was developed. The method is based on the re-
action of trimethylacetoxysilane with powdered boric
acid of chemically pure grade at 110 C for 1 h, with
the subsequent purification of the product by rectifi-
cation in a vacuum.
10 h [6] produced TMSB in 40 and 72% yields, re-
spectively.
To be used in micro- and optoelectronics, TMSB
should be of special purity. This forced the authors to
develop a method for synthesis of high-purity TMSB
by heating trimethylacetoxysilane with powdered
boric acid of chemically pure grade at 110 C:
ACKNOWLEDGMENTS
The study was supported by the Council for Pre-
1721