Continuous organomagnesium synthesis of organometallic compounds

Article abstract of DOI:10.1134/S1070427213030166

Continuous organomagnesium synthesis of a number of organic derivatives of 14th group elements of the periodic table was examined in a column apparatus with an agitator. An effect of a molar ratio of reactants, temperature in a reaction zone, and other factors was studied on the yield and composition of the products.

Full text of DOI:10.1134/S1070427213030166

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 3, pp. 387−393. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © P.A. Storozhenko, A.A. Grachev, A.O. Klochkov, V.I. Shiryaev, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 3,
pp. 418−424.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
Continuous Organomagnesium Synthesis
of Organometallic Compounds
P. A. Storozhenko, A. A. Grachev, A. O. Klochkov, and V. I. Shiryaev
State Research Institute for Chemistry and Technology of Organoelement Compounds, Moscow, Russia
e-mail: shirvi@mail.ru
Received February 22, 2013
Abstract—Continuous organomagnesium synthesis of a number of organic derivatives of 14th group elements
of the periodic table was examined in a column apparatus with an agitator. An effect of a molar ratio of reactants,
temperature in a reaction zone, and other factors was studied on the yield and composition of the products.
DOI: 10.1134/S1070427213030166
Organomagnesium method is one of the most popular
and versatile methods for synthesis of various organic and
organoelemental compounds [1–3]. Organomagnesium
synthesis is widely used in the manufacture of such or-
ganoelemental compounds (OEC) important for industry
and agriculture as organosilicon and organotin. Organo-
silicon compounds (OSC) are widely used as a heat- and
damping fluids, silicon rubbers, unsurpassed sealants,
insulation materials, water repellents, surfactants [4].
volatile and flammable solvents (diethyl ether, THF, etc.)
is a serious threat. The low boiling point and flash point
of diethyl ether and THF (–35 and –14°C, respectively)
limit the initiation temperature and proceeding reactions
of organohalides (especially, organic chlorides) with
magnesium in these solvents [15, 16]. Therefore, ways to
reduce risk in proceeding the organomagnesium synthesis
are invented, for example, replacing these solvents by less
volatile ethers (1,2-dimethoxyethane, diethylene glycol
dibutyl ether, dioxane), reaction of organohalides with
magnesium in a non-ether environment [17, 18].Another
technique to reduce the risk is carrying out the process
in continuous mode. It was suggested various design of
devices for continuous synthesis of organomagnesium
compounds in laboratory and industrial applications
[19, 20].
Organotin compounds (OTC) are used as heat and
light stabilizers of PVC, catalysts of a number of indus-
trial processes such as the production of polyurethanes,
in the esterification for obtaining esters, in cold curing
of silicone rubber, etc. OTCs are used as biologically
active substances for protection of various materials
from biological damage, in agriculture they are applied
as fungicides and acaricides, and in the production of
anti-fouling coatings and dyes [5–13].
The most successful column reactor is that operat-
ing in a regime close to a plug flow regime with use
of which the technology was developed of continuous
organomagnesium synthesis of ethylchlorosilanes and
ethyl (ethoxy) silanes [20]. The advantage of using this
reactor was the possibility of exhaustion ethylmagnium
chlorides produced in the same apparatus, as well as its
high performance. The same reactor was used to develop
a continuous synthesis of other organomagnesium com-
pounds [21].
Nowadays large amounts of OEC application neces-
sitate solution of very urgent task for improvement of
the previously developed and still existing technologies
of their production, which no longer correspond to the
requirements of modern industrial production and, espe-
cially, to criteria of environmental safety set out in the
concept of “green chemistry” [14].
In most processes involved in the synthesis of organo-
magnesium compounds on an industrial scale the use of
The purpose of this study was to examine the oppor-
387

388
STOROZHENKO et al.
tunities and prospects for continuous organomagnesium
method for the synthesis of various OEC. Therewith the
effect of the main parameters of the continuous organo-
magnesium synthesis of OEC was studied in the same
reactor, in which a process of continuous synthesis of
organomagnesium compounds was simulated [21]. The
effect of the molar ratio of the basic reagents, the tem-
perature over the zones of the reactor, and other factors
on the yield and composition of the products formed
were studied.
its test portion was dissolved in toluene–ether in a preset
ratio. Anhydrous tin tetrachloride, silicon tetrachloride,
germanium tetrachloride, and phosphorus chloride oxide
were used without pre-treatment.
Chromatographic analysis of starting materials and
reaction products was carried out on Chromatograph
Crystal 5000.2 using reference samples of OEC on
stainless steel column: Column A: l 2 m, d 3 mm, SE-30
(10%) on Chromosorb W (60/80 mesh); column B: l 2 m,
d 3 mm, PEG-40M (5%) on Chromosorb W (60/80 mesh),
column C: l 1 m, d 3 mm, SE-30 (5%) on Chromosorb W
(60/80 mesh). Carrier gas helium, detector katharometer.
EXPERIMENTAL
Scheme of the laboratory setup is shown in Fig. 1.
Dimensions of the reactor: height of the cylindrical part
500 mm, diameter 40 mm, separator height 100 mm, the
diameter of the cylindrical part 150 mm. The cylindrical
part of the reactor is conventionally divided into four
All solvents were dried before use and distilled. Di-
ethyl ether was dried over calcium chloride and calcium
hydride; THF, over beads of NaOH. Initial organohalides
was dried over calcium chloride and distilled. The dry
chloroethane from bottle was condensed at –20°C and
4a
1c
4b
1b
2b
Fig. 1. Installation of continuous organomagnesium.synthesis of organometallic compounds. (1а–1c) supply tanks; (2а, 2b) metering
pumps; (3) reactor; (4а, 4b) reflux condenser; (5) hydrolyser; (6) settler; (7) magnesium hopper.
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CONTINUOUS ORGANOMAGNESIUM SYNTHESIS
389
equal areas jacketed, in which cooling agent of preset
temperature was supplied from thermostates. The reactor
was equipped with a multibladed agitator and thermo-
couples to measure the temperature over the areas of the
reactor and an inlet and outlet of cooling agent (water or
oil) from the jackets.
the reactor. Tin tetrachloride in the hydrocarbon solvent
was supplied between the first and second areas of the
reactor. Supply of reagents to the reactor by two streams
can also distribute the heat of reaction over zones.
As a n-donor solvent diethyl ether or THF was used,
taken in a molar ratio of 0.75–2.5 to organohalide, ac-
cording to data [21] depending on the organohalide used.
In the continuous process the basic parameters of the
reaction: the molar ratio RX/SnCl4, temperatures in the
areas of the reactor, were refined. In all the experiments
in this series magnesium filled a cylindrical part of the
reactor, i.e., its four zones.
Magnesium (400 g) in the form of pellets of a diameter
0.5–2.5 mm was loaded into the reactor 3 (Fig. 1) in a
nitrogen flow at the operating agitator (ω = 120 rpm) and
also from the storage container 1a with the aid of meter-
ing pump 2a 50 ml of the seed mixture of composition
(ml): 1,2-dibromoethane 20, n-donor 20, toluene 10, was
supplied.After launching of the reaction (the temperature
jump in the first zone of the reactor) mixture no. 1 was
supplied from the container 1a at a preset rate (Table 1).
By the example of chlorobutane the dependence of
the yield and composition of the reaction products on the
molar ratio BuCl/SnCl4 was pictured (Fig. 2). As can be
seen from Fig. 2, with an increase in this ratio from 2.5
to 5.5 there is increase in the total yield of OTC (Fig. 2,
curve 1) from 67 to 100%. The low total yield of OTC in a
molar ratio BuCl/SnCl4 equal to 2.5–3.0 is, probably, due
In 10–15 min after the launching of the reaction the
mixture no. 2 was fed from the storage container 1b with
metering pump 2b (Table 1) at a preset rate to the lower
part of the second or third area of the reactor. Further
the level of magnesium loading in the cylindrical part
of the reactor was ensured by periodic supplement of its
calculated amount from hopper 7. The load sensor such
as γ-relay GR-6S controlled magnesium levels,
1
to the fact that the yield of BuSnCl3 was not accounted
for in it. As it was expected, with increasing the molar
ratio of BuCl/SnCl4 the increase in the yield of OTC was
observed with a high degree of alkylation. Thus, the yield
of Bu2SnCl2 (Fig. 2, curve 2) was reduced from 38 in the
case of the molar ratio of BuCl/SnCl4 equal to 2.5 to 2%
at the molar ratio equal to 4. The yield of Bu4Sn (Fig. 2,
The temperature in the areas of the reactor was main-
tained at the set ranges by adjusting the feeding of cooling
agent, which supplied to the jackets of respective areas,
and by its temperature.
The reaction products from the separator of the reactor
flowed down through a nozzle into a hydrolyzer 5, where
they were treated with 5–10% hydrochloric acid from
a storage container 1 with a given velocity. Hydrolysis
products through hydraulic lock flowed down into the
settler liquid–liquid 6, where there occurred a continuous
separation of the organic and aqueous phases.
After 3–4 hours of continuous operation of the setup
the organic phase for 1 h were collected in the receiver, the
solvent was evaporated, a residue was distilled in vacuo,
and the product was analyzed by GLC. Yield and process
performance (mol h–1 L–1) are presented in Table 1; the
properties and data of elemental analysis, in Table 2.
Because tin tetrachloride with diethyl ether and THF
forms a solid insoluble complex [22, 23] that impedes
supplying the reagents by the metering pump, they were
fed to the reactor by two separate streams by the two me-
tering pumps. The first stream comprising organohalide in
a hydrocarbon solvent (usually toluene) in the presence of
n-donor was supplied from the bottom of the first area of
Fig. 2. Yield of butyltin compounds Х (%) vs. the molar ratio of
BuCl/SnCl4. Yiled: (1) total BunSnCl4–n (n = 2–4); (2) Bu2SnCl2,
(3) Bu4Sn, (4) Bu3SnCl.
––––––––––––––
1 Here and below, the content of butyl trichloro stannane by GLC was
not determined because the compound is highly soluble in acidic
aqueous medium and is virtually absent in the organic phase.
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STOROZHENKO et al.
Table 1. The conditions and results of continuous organomagnesium synthesis of tetraorganosilanes, -germanes, and -stannanes
Temperature over the
1st stream
component, g
2nd stream
n-Donor/RX RX/SnCl4
Yield
R4Sn,
g (%)
areas, °С
Performance,
mol h–1 L–1
w,
mL h–1
component, g
(mol)
w,
mol mol–1
I
II
III–IV
(mol)
mL h–1
EtCl, 284 (4.4);
Et2O, 245 (3.3);
toluene, 334 mL
EtBr, 469 (4.3);
Et2O, 319 (4.3);
toluene, 227 mL
1000 SnCl4, 260.4
0.75
4.4
4.3
50 ± 5 50 ± 5 50 ± 5 233.4
(99.4)
0.414
0.412
(1.0); toluene, 1000
883 mL
1000 SnCl4, 260.4 1000
(1.0); toluene,
1.0
50 ± 5 50 ± 5 50 ± 5 232.6
(99.0)
883 mL
n-BuCl, 250
(2.7); Et2O, 300
(4.05); toluene,
1000 SnCl4, 130.2
(0.5); toluene,
442 mL
500
500
1.5
1.0
5.4
5.5
50 ± 5 50 ± 5 60 ± 5 170.2
(98.0)
0.204
0.204
293 mL
n-BuCl, 255
1000 SnCl4, 130.2
(0.5); toluene,
442 mL
50 ± 5 50 ± 5 60 ± 5 169.0
(97.9)
(2.75); THF, 198
(2.75); toluene,
490 mL
n-OctCl, 557
(3.75); Et2O, 278
(3.75); toluene,
219 mL
1250 SnCl4, 130.2
(0.5); toluene,
542 mL
600
600
1.0
1.0
7.5
8.0
6.1
6.4
50 ± 5 60 ± 5 65 ± 5 281.6
(98.5)
0.205
0.201
0.187
0.201
n-OctCl, 594.6
(4.0); THF, 288.5
(4.0); toluene,
246 mL
1250 SnCl4, 130.2
(0.5); toluene,
542 mL
50 ± 5 60 ± 5 70 ± 5 275.5
(96.4)
s-HexCl, 361.7
(3.05); Et2O,
226.1 (3.05);
1000 SnCl4, 130.2 1000
(0.5); toluene,
1.0
50 ± 5 65 ± 5 75 ± 5 202.9
(89.9)
942 mL
toluene, 318 mL
s-HexCl, 379.5
(3.2); THF, 288.5
(4.0); toluene,
295 mL
1000 SnCl4, 130.2 1000
(0.5); toluene,
1.25
50 ± 5 65 ± 5 75 ± 5 217.8
(96.5)
942 mL
PhCl, 337.7 (3.0); 1250 SnCl4, 130.2
700
2.5
1.5
6.0
6.0
70 ± 5 80 ± 5 90 ± 5 207.8
(97.3)
0.203
0.181
THF, 540.9 (7.5);
toluene, 337 mL
(0.5); toluene,
642 mL
i-AmBr, 453.2
(3.0); Et2O, 300
(4.05); toluene,
216 mL
1000 SnCl4, 130.2 1000
(0.5); toluene,
50 ± 5 50 ± 5 60 ± 5 175.4
(87)
942 mL
i-AmBr, 528.6
(3.5); THF, 315.5
(4.38); toluene,
226 mL
1000 SiCl4, 85.0
(0.5); toluene,
942 mL
1000
500
1.25
1.25
7.0
6.5
70 ± 5 80 ± 5 90 ± 5 128.2
(82)
0.171
0.179
i-AmBr, 490.9
(3.25); THF,
292.9 (4.06);
toluene, 281 mL
1000 GeCl4, 107.2
(0.5); toluene,
442 mL
70 ± 5 80 ± 5 90 ± 5 153.6
(86)
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CONTINUOUS ORGANOMAGNESIUM SYNTHESIS
391
Table 2. Properties and the elemental analysis data of OEC obtained under optimum conditions
Found, %
Calculated, %
Product properties
OEC,
formula
Content of
the basic
(malar mass) substances
bp, °С/ Торр
mp, °С
nd20
d420
С
Н
E
Tetraethyltin,
Et4Sn (234.96)
100
70–72/15
(181 [26])
_
1.4726 (1.4738
[27])
1.1981
(1.1990 [27])
40.76
40.90
8.43
8.58
50.35
50.52
Tetra-n-butyl-
tin,
n-Bu4Sn
(347.17)
99.5
119–122/2
(152–153/8 [26])
_
_
1.4742
1.0550
55.09
55.36
10.17
10.45
34.01
34.19
(1.4727 [27]) (1.0541 [27])
Tetra-n-octyl-
tin,
n-Oct4Sn
(571.60)
98.5
97
189–193/0.4
(268/10 [26])
1.4679
0.9611
66.98
67.24
11.58
11.99
20.53
20.77
(1.4681 [27]) (0.9609 [27])
Tetracyclohex-
yltin, c-Hex4Sn
(451.32)
_
_
259–261
(261–263
[26])
_
_
_
_
63.70
63.87
9.79
9.83
26.36
26.30
Tetraphenyltin,
Ph4Sn (427.13)
98
225–226
(226–227
[26])
67.26
67.49
4.69
4.72
27.85
27.79
Tetraisoam-
yltin
145–149/2
(148–152/3 [28])
_
1.4691 (1.4710 1.006 (1.012
[28]) [28])
59.45
59.57
10.87
11.00
29.15
29.43
i-Am4Sn
(403.28)
Tetraisoamyl-
tin silane
i-Am4Si
148–151/15
(150–152/15 [29])
_
_
1.4487 (1.4472 0.8633 (0.8623 76.54
[29]) [29]) 76.83
13.94
14.19
8.77
8.98
(312.66)
Tetraisoamyl-
tin germane,
i-Am4Ge
122–125/5
(278 [30])
1.4580 (1.4571 0.9324 (0.9340 67.43
[30]) [30]) 67.25
12.11
12.42
20.17
20.33
(357.18)
curve 3) increased rapidly and reached 99% at a molar
ratio of the reactants equal to 5.5. For Bu3SnCl curve
4 has an extreme at the ratio equal to 3.0–3.5, reaching
a minimum yield 1–2% at the molar ratio 5.0–5.5.
of the continuous organomagnesium synthesis of
tetraorganosilane, -germane, and -stannane are presented
in Table 1; the properties of the OEC, in Table 2. It should
be noted that in this case the EOC high yield usually
nearly quantitative are formed.
Similar experiments were performed with other
organohalides and silicon, germanium, and tin
tetrachloride. Optimal conditions and the results
Hourly performance of the setup (Fig. 1), calculated in
view of the volume of its main equipment (2.4 L): reactor,
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STOROZHENKO et al.
Table 3. Performance of synthesis tetraalkyltin by batch and continuous methods
Performance, mol h–1 l–1
Method
Пcont/Пperiodic
References
Et4Sn
n-Bu4Sn
n-Oct4Sn
Periodic
Continous
0.019
0.414
–
–
21.7
6.71
8.44
[23]
Our data
Periodic
Continous
–
0.030
0204
–
[24]
Our data
Periodic
Continous
–
–
0.024
0.205
[25]
Our data
istry, Wilkinson, G., Stone, F.G.A., and Abel, E.W., Eds.,
Oxford: Pergamon Press, 1984.
hydrolyzer, and settler, was 0.412–0.414 for tetraethyltin
and 0.187–0.205 mol h–1 L–1 for other tetraorganotins
(Table 3). For comparison Table 3 shows the performance
of the known methods for obtaining tetraalkyltin based
on periodic organomagnesium synthesis calculated
approximately, since in the examples [23–25] the volumes
of the main equipment are not always given. In these
cases, the volume of the equipment was calculated by the
volume of the loaded reagents, solvents, water, etc. In the
examples also the time of the basic operations (addition,
exposure, hydrolysis, etc.) are not always given, in such
cases the data are taken according to the conventional
practice of the processes. The data in Table 3 show that the
hourly yield per unity of volume of the basic equipment
for continuous organomagnesium method of producing
tetraalkyltin is several times higher than periodic.
4. Butts, M., Cella, J., Wood, C.D. et al., Kirk-Othmer En-
cyclopedia of Chemical Technology, 5th ed. New Jersey:
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tsiklopedicheskii Sprav., 2011, no. 10, pp. 23–35.
9. Shiryaev, V.I. and Storozhenko, P.A., Vse materialy: En-
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As a result of these studies, a continuous organomag-
nesium synthesis of tetraorganosilanes, -germanes, and
-stannanes was developed. The process of obtaining or-
ganoelement compounds differs from the known methods
by high performance and safety that allows attributed it
to the technologies of the 21st century, the concept of
“Green chemistry.”
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