Continuous single-stage organomagnesium synthesis of a mixture of ethylethoxysilanes and dimethylethylethoxysilane

Article abstract of DOI:10.1021/op990011g

Simultaneous synthesis of ethylethoxysilanes and dimethylethylethoxysilane from a mixture of ethyl chloride, tetraethoxysilane, and dimethyldichlorosilane with magnesium (supply rate 75-100 g h^-1) was studied. Schemes of intermediate processes are proposed. Reactivity of dimethyldichlorosilane and diethyldichlorosilane relative to each other is evaluated. Various grades of magnesium are tested. To reduce the amount of regenerated solvent (toluene) its mixtures with oligodiethylsiloxanes are used. The mixture of ethyl-substituted silanes can be used in subsequent preparation of oligo-ethylsiloxane liquids modified with the terminal dimethylethylsiloxy groups, which are characterised by improved lubricating properties.

Full text of DOI:10.1021/op990011g

Organic Process Research & Development 2000, 4, 122−128
Technical Notes
Continuous Single-Stage Organomagnesium Synthesis of a Mixture of
Ethylethoxysilanes and Dimethylethylethoxysilane
Boris A. Klokov*
Silane Joint-Stock Company, 14 ZaitseV street, DankoV, Lipetsk region, 399820 Russia
Scheme 1
Abstract:
Simultaneous synthesis of ethylethoxysilanes and dimethyleth-
ylethoxysilane from a mixture of ethyl chloride, tetraethoxysi-
lane, and dimethyldichlorosilane with magnesium (supply rate
75-100 g h-1) was studied. Schemes of intermediate processes
are proposed. Reactivity of dimethyldichlorosilane and dieth-
yldichlorosilane relative to each other is evaluated. Various
grades of magnesium are tested. To reduce the amount of
regenerated solvent (toluene) its mixtures with oligodiethylsi-
loxanes are used. The mixture of ethyl-substituted silanes can
be used in subsequent preparation of oligo-ethylsiloxane liquids
modified with the terminal dimethylethylsiloxy groups, which
are characterised by improved lubricating properties.
Scheme 2
Introduction
A continuous process developed by us for the synthesis
of ethylethoxysilanes (Scheme 1), which is used in produc-
tion of oligoethylsiloxanes,1,2 and for production of silicone
intermediates (polyolefin catalysis),2a,bis performed with the
excess of granulated magnesium3 in a stirring column
apparatus with a countercurrent mode relative to liquid
reagents.
To improve this process, we proposed using of a mixture
of tetraethoxysilane 3 and diethyldichlorosilane 94,5 in a
continuous process (Scheme 2).
The absence of triethylchloro- 11 and tetraethylsilane 12,
which could have been formed from 9 with 8 (Scheme 3),
is due to silane 9 ethoxylation with ethoxymagnesium
chloride 7 and the reaction of diethyl(ethoxy)chlorosilane
13 with 8 (Scheme 4).
Scheme 3
Scheme 4
(1) Khananashvili, L. M.; Andrianov, K. A. Tekhnologiya elementoorgani-
icheskikh monomeroV i polimeroV (Technology of Organoelement Mono-
mers and Polymers); Khimiya: Moscow, 1983.
The use of the mixture of ethoxysilane 3 and dichlorosi-
(2) Klokov, B. A. Metalloorgan. Khim. 1992, 5(1), 83 (Organomet. Chem.
1992, 5(1), 43) and references therein. (a) Arkles, B. In Handbook of
Grignard Reagents; Silverman, G. S., Rakita, P. E., Eds.; Dekker: New
York, 1996; Chapter 32 and references therein. (b) Kolthammer, B. W. S.
In Handbook of Grignard Reagents; Silverman, G. S., Rakita, P. E., Eds.,
Dekker: New York, 1996; Chapter 33 and references therein.
(3) Vavilov, V. V.; Velikii, V. V.; Gerlivanov, V. G.; Kalliopin, L. E.; Klokov,
B. A.; Medvedev, A. D.; Sakhiev, A. S.; Ufimtsev, N. G. RU Patent 726825,
1985.
(4) Klokov, B. A.; Sobolevskii, M. V.; Sakhiev, A. S.; Ufimtsev, N. G.;
Kuz`min, D. S.; Novikov, V. I.; Grishutin, Yu. P.; Bezlepkina, V. M.;
Balukov, Yu. L.; Koroleva, T. V.; Pashintsev, S. I. RU Patent 1162808,
1985.
lane 9 for the synthesis of ethylsilanes considerably improved
the continuous synthesis: it ensured a higher yield of silane
6 and higher conversion of ethylmagnesium chloride, and
also a lower viscosity of the product.
To improve the properties of oligoethylsiloxanes, we
proposed the using of a mixture of ethoxysilane 3 and
diorganodichlorosilane RR1SiCl2 (R ) Me, R1 ) γ-F3Pr, Cl2-
Ph, C3H4S, Ph) in the continuous process.6-9
In this work we developed and researched the continuous
organomagnesium synthesis of a crude mixture of ethyl-
(5) Klokov, B. A. Zh. Prikl. Khim. 1995, 68(1), 114 (Russ. J. Appl. Chem.
1995, 68(1), 100).
122
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Vol. 4, No. 2, 2000 / Organic Process Research & Development
10.1021/op990011g CCC: $19.00 © 2000 American Chemical Society and The Royal Society of Chemistry
Published on Web 01/05/2000

Scheme 5
Table 1. Composition of the mixture of ethyl-substituted
silanes and conversion (C) of Grignard reagent 8 during the
course of the continuous synthesisa
composition of ethyl-substitued silanes %
duration
(h)
C of 8
(%)
15
9
6
5
4
1
2
3
4
5
6
7
13.8
13.1
12.6
12.9
13.7
13.3
13.1
10.7
8.1
8.1
8.5
8.4
7.2
8.2
7.2
7.6
8.9
8.6
8.4
7.4
8.3
63.0
67.8
67.3
66.3
65.8
68.9
67.5
5.3
3.4
3.1
3.7
3.7
3.2
2.9
89.3
90.5
91.5
91.0
91.0
91.1
91.2
Scheme 6
a The reaction mixture (Scheme 7) was fed from the supply tank with a dosing
pump at a rate of 1100 mL/h. 80 g/h of Mg was loaded at regular intervals (2
times/h).
Table 2. Effect of reagent concentration on composition of
mixture of ethylethoxysilanes and dimethylethylsilanes and
conversion (C) of Grignard reagenta
ethoxysilanes 4-6 and dimethylethylethoxysilane 15 (Scheme
5). We also summarised the results reported previously10,11
and the recent data.
Ethoxysilane 15 is quantitatively formed by ethoxylation
and ethylation of chlorosilane 14 (Scheme 6). Scheme 6 is
confirmed experimentally (see Experimental Section).
M
yield (%)a for compds listed in Scheme 5
C of 8
(%)
entry
3
14
4
5
6
15
16 17 14
Type of Granulated Magnesium Is MGP-2 (1.0-1.6 mm)2,15
1.36 0.11 8.0 83.8 0.0 8.2 0.0 0.0 0.0 90.7
1
2
3
4
5
6
7
8
Results and Discussion
1.32 0.24 7.5 78.5 0.0 13.2 0.0 0.0 0.0 92.3
1.26 0.35 7.8 70.2 0.0 22.0 0.0 0.0 0.0 92.0
1.19 0.50 7.6 65.6 0.0 26.8 0.0 0.0 0.0 92.3
1.07 0.75 1.5 60.8 1.0 25.9 6.8 2.0 2.0 96.3
1.20 0.24 0.0 82.2 2.0 15.8 0.0 0.0 0.0 89.0
1.15 0.35 0.0 78.0 1.5 20.5 0.0 0.0 0.0 89.0
1.09 0.50 0.0 63.5 3.4 25.6 3.0 1.5 3.0 90.7
The effect of different parameters on composition of 4-6,
15-17, and conversion of 8 was studied and is discussed in
the following sections.
Determination of a Relative Reactivity of 14 and 9.11
First of all, we evaluated the reactivity of 14 and 9 relative
to each other (Scheme 7).
As seen from the test results (Scheme 7; Table 1),
products obtained from a mixture of 3.00 M 2, 1.19 M 3,
0.25 M 9, and 0.25 M 14 are ethyl-substituted ethoxysilanes
4, 5, 6 (0.124 M), 15 (0.25 M), and dichlorosilane 9 (0.126
M).
Type of Milled Magnesium Is MPM-1 (1.0-1.6 mm)13-15
1.26 0.29 0.0 81.5 0.5 18.0 0.0 0.0 0.0 94.0
9
Type of Granulated Magnesium Is L-29 (1.0-2.5 mm)2,15
10 1.26 0.29 6.5 75.3 0.6 17.6 0.0 0.0 0.0 91.0
a The weight content of the component is determined from the data of
chromatographic analysis. The deviation from the average values did not exceed
0.2% (at content of component up to 20%) and 1.0% in all other cases.
The relative contents of 6 and 9 (6:9 ) 1:1) and the
complete conversion of 14 into 15 show that the reactivity
of 14 into 15 is higher by a factor of 2 than the reactivity of
9 into 6.
Thus, dichlorosilane 14 is well-suited for continuous
synthesis of ethyl-substituted ethoxysilanes 4-6 and 15.
The Effect of Concentration of 3 and 14 on the
Composition of 4-6 and 15. Then, we studied the influence
of the concentrations of the starting reagents 3 and 14 on
the composition of the synthesis products (Table 2).
It is clearly seen that an increase in concentration of 14
in the reaction mixture results in increasing of the amount
of triorganosilane 15 (entries 1-5) and ethylmagnesium
chloride conversion (from 90.7 to 96.3%).
Diethylsilane 5 constitutes the greater part of the com-
position of the synthesis products (Table 2). The composition
of ethylethoxysilanes 4, 5 (entries 1-4) or 5, 6 (entries 6-9),
or 4-6 (entries 5, 10) can be controlled by the concentration
of 3 and 14. Inputing 9 into the mixture of reagents (Scheme
2) was necessary to obtain good yields of 6 (Table 1).
The fact that the reaction products contain practically no
tetraethoxysilane and a low amount (0-8%) of ethyltri-
ethoxysilane indicates relatively high rates of reactions
(Scheme 1; n ) 1, 2); a high dichlorosilane 14 content
suggests rather low rates of reactions (Scheme 8).
(6) Klokov, B. A.; Uvimtsev, N. G.; Grishutin, Yu. P.; Burilov, K. A.;
Sobolevskii, M. V.; Phedetsov, E. A.; Skorokhodov, I. I. RU Patent
1621466, 1994.
(7) Klokov, B. A.; Grishutin, Yu. P.; Sobolevskii, M. V.; Skorokhodov, I. I.;
Uvimtsev, N. G.; Burilov, K. A.; Simanenko, Z. A. RU Patent 1657514,
1991.
(8) Klokov, B. A.Zh. Prikl. Khim. 1998, 71(3), 461 (Russ. J. Appl. Chem. 1998,
71(3), 479).
(9) Klokov, B. A. Zh. Prikl. Khim. 1998, 71(9), 1493 (Russ. J. Appl. Chem.
1998, 71(9)), 1587.
Therefore, under conditions of the single-stage continuous
organomagnesium synthesis, the reactivity of ethoxysilanes
3 and 4 (catalysts of ethylmagnesium chloride formation)
toward ethylmagnesium chloride is higher than that of
dichlorosilane 14. This effect stems from formation of
complexes 8 with 3 and 4.12
(10) Klokov, B. A.; Sobolevskii, M. V.; Tivanov, V. D.; Isaeva, O. V.; Khe, L.
N.; Savina, T. M. Khim. Prom’st. 1995, 27(11), 672 (Russ. Chem. Ind.
1995, 27(11), 33).
(11) Klokov, B. A. Tez. Dokl. Symp. po Khimii i Primeneniyu Phosphor, Sera
i Kremniiorganicheskikh Soedinenii “Peterburgskie Vstrechi-98” (Abstr.
All-Russia Symposium on the Chemistry and Practical Use of Phosphorus,
Sulfur, and Organosilicon Compounds “Peterburg’s Meetings-98”) St.
Peterburg, 1998, 296.
Vol. 4, No. 2, 2000 / Organic Process Research & Development
•
123

Scheme 7
Scheme 8
Small quantities of 8 (1.6-2.8%) are swept away by the
reaction products (Table 5).The yield of Grignard reagent 8
reaches 97.9% (entry 5).
Therefore, the procedure developed in this work allows
us to control the composition of the reaction products, and
conversion of the initial reagents and intermediates is almost
complete.
Table 3. Dimethyldichlorosilane conversion in continuous
organomagnesium synthesis of ethylethoxysilanes
Effect of Type of Magnesium. Next, we tested a various
grades of magnesium. The results (Table 2) show that use
of mechanically activated type of magnesium (entry 9) makes
it possible to obtain a synthesis product with a high selectivity
of the Grignard reagent 8 (and an appreciably lower viscosity
in pilot installations). This can apparently be explained by
the higher rate of the process of nucleus formation of the
Grignard reagent (milled grades of magnesium exhibit a
higher activity due to lattice defects), which lowers the size
of its particles, increases the rates of their reaction, and
changes the size of the particles of the formed magnesium
salts 7 and 10. Similar results were obtained when using
tetrachlorosilane13,14 or phenylmagnesium chloride (in situ).14-17
The minimum amount of magnesium (0.2-3.5%) is carried
away by the synthesis products (Table 6). Thus, granulated
and milled types of magnesium are well-suited for continuous
synthesis of ethyl-substituted silanes.
In 10 h of continuous operation, the initially loaded
magnesium (500 g) is twice replaced completely by mag-
nesium loaded in the course of the reaction. Therefore, the
apparatus design and size of magnesium grain (1.0-1.6 mm)
provide effective removal of solid products (magnesium salts
7 and 10, and Grignard reagent 8) as well as complete (96.5-
99.8%) conversion of magnesium.
amount (%) of 7
M of 14
Yield (M) of conversion product
consumed in 14
initial final
15
16
17
ethoxylation
0.11 0.00
0.24 0.00
0.35 0.00
0.50 0.00
0.75 0.04
0.24 0.00
0.35 0.00
0.50 0.04
0.29 0.00
0.29 0.00
0.11
0.24
0.35
0.50
0.53
0.24
0.35
0.38
0.29
0.29
0.00
0.00
0.00
0.00
0.13
0.00
0.00
0.05
0.00
0.00
0.00
0.00
0.00
0.00
0.04
0.00
0.00
0.03
0.00
0.00
4.2
9.5
14.5
22.0
24.8
9.9
15.1
17.0
11.5
11.9
Table 4. Content of ethylmagnesium chloride in the
producta
Content of EtMgCl (%) in expt N
duration of
synthesis (h)
1
2
3
4
5
6
7
8
10
2
3
4
5
6
0.49 0.61 0.37 0.23 0.34 1.24 0.41 0.49 0.22
0.29 0.46 0.35 0.34 0.26 1.51 0.31 0.36 0.45
0.51 0.67 0.36 0.41 0.43 1.44 0.49 0.43 0.54
0.60 0.68 0.35 0.27 0.38 1.12 0.59 0.41 0.50
0.69 0.88 0.56 0.30 0.35 1.41 0.73 0.31 0.58
Effect of Type of Solvent: A Mixture of Toluene with
Oligoethylsiloxanes. After that, to reduce the amount of
regenerated solvent (toluene), by known procedures,18,19 we
proposed using a continuous process of its mixture with
oligoethylsiloxanes (up 20%) modified with dimethylethyl-
siloxy groups /bp 60-190 °C/1-3 Torr/ (entry 10). It
allowed us to decrease the load on the stirrer motor and to
stabilize continuous working of the reactor. These effects
a A 0.10% content of ethylmagnesium chloride in the resulting product
corresponds to 0.38% of the theoretical amount.
The relative contents of the reaction products (entries 5,
8; Table 2) show that the rates of dichlorosilane 14
ethoxylation and its subsequent conversion to triorganosilane
15 (Scheme 6) are higher by a factor of 3-6 than the rate
of its alkylation by 8 (Scheme 8). The quantity of ethoxy-
magnesium chloride 7 reacted with dichlorosilane 14 in-
creases with increasing content of the latter in the reaction
mixture. Note, that although the reaction products contain
large amounts of 7 and 14, not more than 25% of 7 is
involved in the reaction (Table 3).
The lack of ethyl chloride 2 in the reaction products and
in the gaseous phase in the reactor separator (Table 4)
indicates its complete conversion. These data show that
among side reactions accompanying Grignard reagent 8
formation, hydrogen abstraction from the solvent molecule
is predominant.
(13) Klokov, B. A.; Sobolevskii, M. V.; Uvimtsev, N. G.; Grishutin, Yu. P.;
Burilov, K. A.; Simanenko, Z. A.; Putintsev, Yu. I.; Philatov, A. P. RU
Patent 1626653, 1994.
(14) Klokov, B. A.; Grishutin, Yu. P.; Shajachmetov, B. M.; Putintsev, Yu. I.;
Anochin, N. Ph.; Ershova, N. M.; Phedetsov, E. A. RU Patent 1626654,
1994.
(15) Klokov, B. A. Zh. Prikl. Khim. 1997, 70(7), 1191 (Russ. J. Appl. Chem.
1997, 70(7), 1130).
(16) Klokov, B. A. Zh. Prikl. Khim. 1997, 70(8), 1398 (Russ. J. Appl. Chem.
1997, 70(8), 1330).
(17) Klokov, B. A. Zh. Prikl. Khim. 1998, 71(3), 458 (Russ. J. Appl. Chem.
1998, 71(3), 476).
(18) Klokov, B. A.; Grishutin, Yu. P.; Bezlepkina, V. M.; Kleinovskaya, M.
A.; Yakovleva, L. N.; Eremina, A. A. RU Patent 1002295, 1983.
(19) Klokov, B. A.; Sobolevskii, M. V.; Sakhiev, A. S.; Grishutin, Yu. P.;
Bezlepkina, V. M. Protsessy i Apparaty Elementoorganicheskikh proiz-
VodstV (Processes and Apparatus of the Organoelemental Industry);
GNIIKhTEOS: Moscow, 1985; p 97.
(12) Voronkov, M. G.; Mileshkevich, V. P.; Yuzhelevskii, Yu. A. SiloksanoVaja
SVyaz’ (The Siloxane Bond); Nauka: Novosibirsk, 1976.
124
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Table 5. Composition of the gas phase in the separator of the reactor
gas content (vol %) in expt N
compnt
1
2
3
4
5
6
7
8
10
ethylene
ethane
butane
ethyl
chloride
toluene
7
10-16
51-60
15-20
0.1-0.2
3-5
74-81
7-9
0
4-5
79-81
7-8
0
17
46
17
0
2-5
26-45
5-7
0
4-7
54-74
11-15
0
4-5
30-44
6-12
0
6
70
9
65
12
0
0
16
10-13
7-15
6-9
20
42-58
12-19
38-56
15
Table 6. Content of magnesium in the producta
from 1.260 mol of tetraethoxysilane and 0.335 mol of
diethyldichlorosilane.
Content of Mg (%) in expt N
duration of
Hence, these modified liquids were used as a basis for
technical liquid whose compounding and preparation pro-
cedure were developed at VNII NP (All-Russia Research
Institute of Oil Refining). The main results of this work were
patented.20,21
synthesis (h)
1
2
3
4
5
7
9
10
2
3
4
5
6
0.01 0.01 0.21 0.04 0.23 0.02 0.24 0.00
0.01 0.01 0.15 0.24 0.27 0.02 0.52 0.01
0.02 0.02 0.19 0.24 0.25 0.06 0.24 0.01
0.05 0.01 0.09 0.15 0.26 0.02 0.53 0.01
0.09 0.02 0.04 0.21 0.16 0.01 0.38 0.01
Conclusions
a A 0.10% content of magnesium in the resulting product corresponds to 1.37%
of the loaded amount.
We have presented an efficient route for the commercial-
scale manufacture of the modified oligoethylsiloxanes with
the terminal dimethylethylsiloxy groups, which are character-
ized by improved lubricating properties. We have developed
for the first time and put into operation on a pilot scale the
efficient continuous organomagnesium synthesis of ethyl-
substituted silanes from the mixture of ethyl chloride,
tetraethoxysilane (catalyst of ethylmagnesium chloride (in
situ) formation), and dimethyldichlorosilane. We have dem-
onstrated an original method for the direct conversion of
dimethyldichlorosilane to dimethylethylethoxysilane (Scheme
6). The granulated and milled (better) types of magnesium
are well-suited for continuous synthesis of ethyl-substituted
silanes. Conversion of the initial reagents and intermediates
is almost complete. We proposed using of mixture of toluene
with oligoethylsiloxanes (up 20%) modified dimethylethyl-
siloxy groups/bp 60-190 °C/1-3 Torr/ in continuous
process. It allowed us to decrease the load on the stirrer motor
and stabilized continuous working of the reactor. The
procedure have developed in this work allows us to control
the composition and properties of the reaction products and
some properties of modified oligoethylsiloxanes (are deter-
mined by the content of 3 and 14 into the reaction mix-
ture).
stem from formation of oligosiloxane complexes with
magnesium salts 7 and 10, and from the lubricating properties
of oligoethylsiloxanes.
Thus, the procedure developed in this work allows us to
control the composition and properties of the reaction
products, which are used in subsequent preparation of
modified oligoethylsiloxanes. And conversion of the initial
reagents and intermediates is almost complete.
Preparation of Modified Oligoethylsiloxanes. Finally,
from the reaction products (without recovery of individual
monomers) we recovered for the first time oligoethylsiloxane
liquids with the terminal dimethylethylsiloxy groups.
Some properties of oligoethylsiloxanes are presented in
Table 7. As can be seen, the properties of these compounds
are determined by the content of the terminal triorganosiloxy
groups (or by the content of 3 and 14 into the reaction
mixture).
From the reaction product (entry 1; Table 2,7), we
obtained PES-5 polisiloxane liquid which meets the require-
ments of the All-Union State Standard (GOST) 13004-77
(viscosity 219 centistoke; flash point 265 °C; pH 6.5; silicon
content 27.9%; ethoxy group and moisture contents less than
0.25 and 0.005%, respectively).
From the reaction product (entry 3, Table 2,7), we
obtained PES-7 polisiloxane liquid which meets the require-
ments of the All-Union State Standard (GOST) 5.868-71
(viscosity 45.7 centistoke; flash point >200 °C; pH 6.4;
silicon content 27.9%; ethoxy group and moisture contents
less than 0.25 and 0.005%, respectively).
It is important to note, that the lubricating properties of
these liquids (determined by E. B. Markina /VNII NP/) are
significantly better than those of the nonmodified compounds.
For example, the diameter of the wear spot for fraction 7
and 5 (entries 3, 4, 6, and 7)/test conditions: 50 N, 50 °C,
2h/ is 0.35, 0.32, 0.30, and 0.60 mm, respectively, i.e., lower
than 0.73 mm in the case of nonmodified fraction 5 prepared
Experimental Section
General Procedures. All reagents and solvents were
obtained from SILANE and used without further purification.
The purity of starting magnesium: MGP-2 (96-98%);
MPM-1 (>99%); L-29 (96-98%).
The liquid phase obtained in the synthesis was separated
by centrifugation and analyzed on an LKhM-80 chromato-
graph5 (2 m × 4 mm column, 5% E-301 on Celite 545,
(20) Klokov, B. A.; Grishutin, Yu. P.; Sobolevskii, M. V.; Koroleva, T. V.;
Novikov, V. I.; Markina, E. B.; Sheinina, S. Z.; Vlasova, T. A. RU Patent
2027718, 1995.
(21) Klokov, B. A.; Grishutin, Yu. P.; Sobolevskii, M. V.; Koroleva, T. V.;
Novikov, V. I.; Markina, E. B.; Sheinina, S. Z.; Vlasova, T. A. RU Patent
2048486, 1995.
Vol. 4, No. 2, 2000 / Organic Process Research & Development
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125

Table 7. Properties of oligomer fractions
viscosity refractive density
viscosity refractive density
fraction bp (°C) yield at 20 °C index at at 20 °C
fraction bp (°C) yield at 20 °C index at at 20 °C
entry
1
N
1-3 Torr (%)
(cst)
20 °C
(g cm-3
)
entry
5
N
1-3 Torr (%)
(cst)
20 °C
(g cm-3
)
2
3
4
5
1
2
3
4
5
1
2
3
7
1
2
3
7
110-150
6.3
9.3
13.6
36.1
212.5
a
1.4341
1.4349
1.4381
1.4485
1.4233
1.4338
1.4334
1.4371
1.4433
1.4278
1.4301
1.4318
1.4378
1.4241
1.4275
1.4312
1.4371
0.956
0.960
0.975
0.995
0.874
0.949
0.956
0.969
0.991
0.919
0.931
0.948
0.971
0.886
0.916
0.941
0.967
1
2
3
7
1
2
3
7
1
2
3
7
1
2
3
7
1
2
3
7
7
60-110
2.9
2.4
4.4
1.4196
1.4245
1.4300
1.4358
1.4292
1.4309
1.4338
1.4402
1.4280
1.4304
1.4348
1.4412
1.4214
1.4270
1.4308
a
0.942
0.905
0.931
0.951
0.902
0.932
0.940
0.961
0.879
0.907
0.931
0.949
0.866
0.906
0.921
a
150-185 24.4
185-250 17.8
110-150 18.7
150-190 33.7
9.4
>250
51.5
1.2
>190
44.7
0.7
29.0
2.6
5.0
10.0
36.8
2.2
3.8
9.3
31.4
2.0
4.4
9.0
24.5
2.6
8.0
10.9
60.4
63.5
2
60-110
6
7
60-110
110-150 11.5
150-185 20.4
185-250 22.5
11.9
12.6
28.1
143.5
4.3
110-150 17.5
150-190 34.4
>190
47.4
1.3
8.6
>250
44.4
0.8
60-110
110-150
3
4
60-110
110-150 14.4
150-190 30.2
6.1
150-190 45.1
12.0
45.7
3.0
>190
45.0
5.2
>190
54.6
2.3
9.9
8
60-110
60-110
110-150
110-150 13.7
150-190 34.8
4.9
10.5
38.6
150-190 32.3
>190
46.0
0.7
5.1
>190
52.5
9
60-110
110-150
1.4251
1.4326
1.4336
1.4408
a
0.900
0.930
0.942
0.963
a
150-190 29.5
>190
>190
64.7
63.0
10
a Not measured.
detector temperature 350 °C, vaporizer temperature 350 °C,
programmed heating from 50 to 300 °C at a rate of 12 deg
min-1, carrier gas helium, flow rate 50 mL min-1, detector
current 100 mA).
into a 1-L round-bottom four-necked flask equipped with a
mechanical stirrer with a hydroseal, a reflux condenser, a
thermometer, and a dropping funnel. Mg was heated to 75
°C and stirred at this temperature for 20 min. To the Mg
turnings was quickly added a portion (10-20 mL) of a
mixture of 2 (70.0 mL, 1.000 mol), 3 (101.0 mL, 0.455 mol),
and toluene (150.0 mL). The reaction self-initiated within
10 min. The remaining solution of 2 and 3 was added
(continuous addition) into the flask over 20 min at 55-70
°C; a cooling bath was needed to keep the temperature within
this range. When the addition was complete, the mixture was
stirred for 2 h at 60 °C and a sample was withdrawn to
analyse the reaction products (a).
The content of magnesium in the product was determined
from the amount of hydrogen released after the decomposi-
tion of the sample (0.3-0.5 g) with 20 mL of sulfuric acid
(1:3), using a 2 m × 4 mm column packed with zeolite 5A
(0.250-0.315 mm grains) and the calibration curve. Tem-
peratures of the vaporizer, the column, and the detector were
50, 35 and 40 °C, respectively. The carrier gas (argon) flow
rate was 60 mL min-1. The detector current was 100 mA.
The hydrogen content was determined from the peak height
on the 8-mV scale of potentiometer from two parallel
findings.
The ethylmagnesium chloride content was determined
from the amount of ethane formed after the sample (3.0-
9.0 g) decomposition with distilled water (20 mL) using a 2
m × 4 mm column packed with Polysorb-1 and the
calibration curve. Temperatures of the vaporizer, the column,
and the detector were 50, 35, and 40 °C, respectively. The
carrier gas (helium) flow rate was 60 mL min-1. The detector
current was 100 mA. The ethane content was determined
from the peak area from two parallel findings.
Silane 14 (30.0 mL, 0.250 mol) was added to the above
reaction product over a 1 min period at 45 °C, the reaction
mixture was further stirred for 1 h at 63 °C, and the sample
for analysis was taken (b).
(B) Similar to the procedure of (A) an amount of Mg
turnings (40 g, 1.646 mol) was heated to 75 °C and stirred
at this temperature for 20 min. To the Mg turnings was
quickly added a portion (10-20 mL) of a mixture of 2 (105.0
mL, 1.500 mol), 3 (147.0 mL, 0.660 mol), 14 (30.0 mL,
0.250 mol), and toluene (240.0 mL). The reaction self-
initiated within 5 min. The remaining solution of 2, 3, and
14 was added (continuous addition) into the flask over 35
min at 60-65 °C; a cooling bath was needed to keep the
temperature within this range. When the addition was
complete, the mixture was stirred for 2 h at 60 °C, and a
sample was withdrawn to analyse the reaction products
(c).
The gaseous phase from the reactor separator was
analyzed on an LKhM-8MD chromatograph (2 m × 3 mm
column packed with Polysorb-1). The detector and vaporizer
temperature was 200 °C; the columns were heated in
programmed mode with a 12 deg min-1 heating rate over
the temperature range from 35 to 200 °C. The carrier gas
(helium) flow rate was 30 mL min-1. The detector current
was 90 mA.
(C) The sample of reaction products (d) was prepared
from 1, 2, 3, and 14 (60.0 mL, 0.500 mol) in a manner similar
to that described above (B).
Control Batch Synthesis of Ethyl-Substituted Silanes.
(A) A batch of Mg turnings (27.0 g, 1.111 mol) was charged
126
•
Vol. 4, No. 2, 2000 / Organic Process Research & Development

Table 8. Parameters of continuous organomagnesium synthesis of ethyl-substituted silanes
feed rate
of the
heat removal
from the
reaction
first reaction
zone
Temperature in indicated zones of synthesis reactor (°C)
mixture
exptN
(ml h-1
)
1
2
3
4
separator
82
(kcal h-1
)
1
2
1030-1080
1050-1120
960-1030
1050-1140
1040-1110
1010-1060
980-1220
1150-1220
1160-1270
1100-1220
80-81
79-82
77-83
80-86
78-83
95-98
88-95
90-91
86-92
84-90
67
65-66
65-66
63-64
63-64
64
48-58
48-50
54-59
55-63
66-70
86
172
65-68
64-66
64-65
68
85-87
85-86
86
80-82
81-85
86
196-208
162-177
172-184
192-194
195-219
195-228
227-248
222-234
220-233
3
4
5
86
83
6
50-60
48-50
58-64
63-69
62-74
83
76
7
83
74
8
84-85
76-78
77-79
75-76
73-75
73-75
9
10
Table 9. Characteristics of intermediate products and parameters of catalic rearrangement (CR) of modified oligoethylsiloxanes
(OES)
Solution of OES
Solution of MgCl
parameters of CR
viscosity
of OESa
(cSt)
expt
N
OES
d
MgCl2
(%)
d
HCl
τ
t
(%)
(g cm-3
)
(g cm-3
)
(g L-1
)
(h)
(°C)
1
2
27.9
28.6
28.8
28.7
28.0
23.6
26.4
25.0
34.3b
34.7c
0.89
0.88
0.88
0.88
0.87
0.87
0.87
0.87
0.88
0.88
19-22
18-22
19-25
19-21
18-22
27-32
22-25
28-32
28-33
21-26
1.14-1.15
1.15-1.16
1.15-1.16
1.15-1.17
1.15-1.17
1.18-1.20
1.16-1.18
1.20-1.23
1.18-1.20
1.18-1.21
20-52
20-38
31-46
22-52
20-43
27-36
42-52
21-31
30-42
41-57
7.9/42.0
5.3/24.4
4.7/14.7
4.6/13.7
3.6/9.9
4.8/14.4
3.6/11.1
4.4/9.9
6.5/23.1
5.7/24.0
12
12
18
18
18
28
26
30
22
21
110-122
90-110
120-130
120-130
120-130
130-140
133-140
140
3
4
5
6
7
8
9
100-122
107-137
10
aBefore CR/after CR. b OES were added to the synthesis products. c OES were added to the reaction mixture in place of part of toluene.
The results of analysis of (a-d) (wt %) show that in our
tests ethoxylation of 14 follows Scheme 6.
(a)
(b)
(c)
(d)
Si(OEt)4
1.4
21.6
77.0
0.0
1.0
15.7
56.1
0.0
6.5
17.5
48.1
0.0
15.9
11.8
30.6
0.0
EtSi(OEt)3
Et2Si(OEt)2
Et3SiOEt
Me2SiCl2
0.0
0.0
0.0
0.0
17.4
2.2
7.6
0.0
2.1
25.8
0.0
6.8
6.6
26.8
1.5
Me2EtSiCl
Me2EtSiOEt
X
0.0
conversion of EtMgCl, %
80.1
82.3
87.6
85.7
Continuous Synthesis. The continuous synthesis was
carried out using a column apparatus (Figure 1)2 divided
along the vertical into four zones by jackets. The zones are
numbered from the bottom to the top. To initiate the process,
we fed into the reactor from a supply tank using a dosing
pump 100 mL of toluene. Then 100 g of magnesium was
loaded into the reactor through a funnel on the cap of the
reactor separator. The contents of the reactor were heated to
to 60-70 °C by feeding hot water from a thermostat to the
jacket of the first zone and a heat-transfer agent from a
another thermostat to the jackets of the fourth zone and the
separator. When the temperature of the first zone reached
60 °C, we began introduction of the reaction mixture of a
given composition from the supply tank with the dosing
pump at a rate 400-600 mL h-1. After an induction period
Figure 1. Synthesis reactor:2 1, connecting pipe for mixture
input; 2, stirrer; 3, cooling jacket; 4, reactor body; 5, paddle;
6, frame; 7, connecting pipe for magnesium input; 8, thermo-
couple pocket; 9, connecting pipe for product removal; 10,
separator.
Vol. 4, No. 2, 2000 / Organic Process Research & Development
•
127

(usually 5-20 min), the temperature into the first zone
increased to 80-100 °C, indicating the completion of the
induction period and onset of the reaction. The water was
fed through the jacket of the first reactor zone for cooling.
A heat-transfer agent was fed through the jackets of the
fourth zone and the separator from a another thermostat.
Every 5 min, 50 g of magnesium was introduced into the
reactor through the funnel, until the total amount in the
reactor became 500 g; at this moment, we began to take off
the synthesis product from the reactor into the receiver or
into the continuous hydrolysis unit.
After that the feeding rate was increased to the prescribed
value over a period of 1 h. Simultaneously the prescribed
synthesis temperature mode of the process was established
by controlling the input rate of the cooling water and the
temperature of the heat-transfer agent. The rate of stirrer
rotation was maintained at 120-140 rpm. The additional
amounts of magnesium (up to the prescribed amount) were
loaded at regular intervals (2 times an hour). The mixture
moved in the reactor from the bottom to the top through the
magnesium bed, reacting with this layer.
the reactor separator, samples were withdrawn every hour
to determine the composition of the gaseous phase.
After collecting the required amount of the product, the
heating was swiched off, and the reactor was cooled to 40
°C by feeding water into the jackets. Simultaneously, toluene
was fed into the reactor (usually 0.5 L). Then the bottom
cap was screwed off, and the contents were unloaded into a
special vessel.
Safety and hazards associated to the continuous process
are typical of the batch process.
Synthesis of Modified Oligosiloxanes. The syntheses
were performed according to the procedure given previ-
ously.17,22 The parameters of the catalytic rearrangement (CR)
and the characteristics of the intermediates are listed in Table
9.
Acknowledgment
The author is grateful to the collaborators in GNIIKh-
TEOS (State Research Institute of Chemical Technology of
Organoelement Compounds), VNII NP and Joint-Stock
Company SILANE, which are the authors of patents, refs
20 and 21,20,21 for helpful discussion aimed at improving
properties of the final products.
The parameters of the continuous synthesis are listed in
Table 8. The synthesis product as a suspension of a
magnesium salts into ethylethoxysilanes and toluene from
the separator was directed into a collector (entries 1-5, 9)
or into a setup for continuous hydrolysis (entries 6-8, 10).
From the discharge duct, samples were withdrawn every hour
to determine the composition of the synthesis product. From
Received for review February 22, 1999.
OP990011G
(22) Klokov, B. A. Zh. Prikl. Khim. 1994, 67(10), 1703 (Russ. J. Appl. Chem.
1994, 67(10), 1497).
128
•
Vol. 4, No. 2, 2000 / Organic Process Research & Development