Liquid-Phase Chlorination of Chlorosilyl-substituted Ethylenes and Acetylenes

Article abstract of DOI:10.1023/A:1026174517484

The liquid-phase chlorination of bis(chloromethylsilyl)ethylenes and -acetylenes Me_nQ_3-nSiZ · SiMe_nCl _3-n (n = 0-3; Z = CH=CH, C≡C) was studied. Novel carbochlorosilanes were obtained and characterized. The effe

Full text of DOI:10.1023/A:1026174517484

Russian Journal of General Chemistry, Vol. 73, No. 5, 2003, pp. 708 710. Translated from Zhurnal Obshchei Khimii, Vol. 73, No. 5, 2003,
pp. 749 751.
Original Russian Text Copyright
2003 by Lakhtin, Sheludyakov, Chernyshev.
Liquid-Phase Chlorination of Chlorosilyl-substituted Ethylenes
and Acetylenes
V. G. Lakhtin, V. D. Sheludyakov, and E. A. Chernyshev
Gosudarstvennyi nauchno-issledovatel’skii institut khimii i tekhnologii elementoorganicheskikh soedinenii
State Research Center of the Russian Federation, Moscow, Russia
Received May 4, 2001
Abstract The liquid-phase chlorination of bis(chloromethylsilyl)ethylenes and -acetylenes MenCl3 nSiZ
SiMenCl3 n (n = 0 3; Z = CH=CH, C C) was studied. Novel carbochlorosilanes were obtained and charac-
terized. The effect of substituents on the activity of the multiple bond of chlorosilylolefins in the reaction
studied was determined.
Earlier [1] we studied the liquid-phase chlorination
of C-chlorovinylsilanes to show that the reaction
occurs unselectively as (a) chlorine addition at the
multiple bonds of chlorosilylolefins to form dichloro-
ethylsilanes, (b) chlorination of methyl groups,
(c) substitutive chlorination of the dichloroethyl
groups formed, and (d) decomposition of chlorine-
substituted silanes.
By competitive chlorination of chlorosilylethylenes
and chloroethylenes [1] we earlier found that the Cl3Si
group stronger, compared with chlorine, deactivates
the olefin double bond. In the present work we tried to
estimate the effect of substitution of the chlorine
atoms in the trichlorosilyl group on the relative
Table 1. Chlorination conditions and adduct yieldsa
Proceeding with these studies we performed an
analogous liquid-phase chlorination reaction with bis-
(chloromethylsilyl)ethylenes and -acetylenes MenCl3 n
SiZSiMenCl3 n (n = 0 3; Z = CH=CH, C C) in the
absence of catalysts and solvents. It was found that in
these reactions, too, chlorine addition to the multiple
bonds occurs, followed by substitutive chlorination of
the chloroethyl and methyl substituents at silicon and
decomposition. Accumulation of more methyl groups
at the silicon atom facilitates all the mentioned
reactions.
Synthesis
conditions
Yield,
%
Compound
t, C time, h
Cl3SiCCl=CClSiCl3 (I)
Cl3SiCCl2 CCl2SiCl3 (II)
MeCl2SiCCl=CClSiMeCl2
(III)b
22 87
22 87
22 115
5.5
5.5
3.5
52
43
58
MeCl2SiCCl2 CCl2SiMeCl2
22 115
22 94
3.5
3.5
39
47
(IV)b
Bis(trichlorosilyl)- and bis(dichloromethylsilyl)-
acetylene derivatives take up only one or two chlorine
molecules at the multiple bonds. With bis(chlorodi-
methylsilyl) and bis(trimethylsilyl) derivatives, pro-
found alkylation of the methyl groups occurs (10
18%) along with adduct formation.
Me2ClSiCCl=CClSiMe2Cl
(V)b
Me2ClSiCCl2 CCl2SiMe2Cl
22 94
22 68
3.5
28
(VI)c
Me3SiCCl=CClSiMe3 (VII)
3.0
3.0
6.0
4.5
38
17
82
43
Me3SiCCl2 CCl2SiMe3 (VIII) 22 68
Cl3SiCHCl CHClSiCl3 (IX) 22 84
MeCl2SiCHCl CHClSiMeCl2 22 75
(X)c
Bis(chloromethyl)ethylenes are alkylated even less
selectively. Here only Cl3SiCH=CHSiCl3 forms an
adduct in high yield (Table 1). Beginning with the
MeCl2Si derivative, vigorous substitutive chlorination
of the chloroethyl bridge between the silicon atoms
occurs along with chlorine addition by the double
bond, whereas in the Me2ClSi and Me3Si derivatives,
two more processes, chlorination of the methyl groups
and decomposition. The reaction conditions and adduct
yields are listed in Table 1.
a
Substitutive chlorination products were not isolated because of
b
the low yields and close boiling points. Compounds III, IV,
c
and V are prepared for the first time. Compounds VI and
could not be isolated and characterized because of the pre-
sence of closely boiling admixtures. Their contents in the
reaction mixtures and yields were estimated by GLC.
1070-3632/03/7305-0708$25.00 2003 MAIK Nauka/Interperiodica

LIQUID-PHASE CHLORINATION OF CHLOROSILYL-SUBSTITUTED ETHYLENES
709
Table 2. Competitive chlorination of equimolar mixtures of chlorosilylolefins
Reagent molar ratios during reaction
Run
Initial mixture
no.
0.2 h
0.5 h
1.0 h
1.2 h
1.5 h
2 h
1
2
3
4
5
6
7
8
ClHC=CHCl/Cl3SiCH=CHCl
ClHC=CHCl/MeCl2SiCH=CHCl
ClHC=CHCl/Me2ClSiCH=CHCl
ClHC=CHCl/Me3SiCH=CHCl
Cl3SiCH=CHCl/Cl3SiCH=CHSiCl3
MeCl2SiCH=CHCl/MeCl2SiCH=CHSiMeCl2
Me2ClSiCH=CHCl/Me2ClSiCH=CHSiMe2Cl
Me3SiCH=CHCl/Me3SiCH=CHSiMe3
0.98
0.99
1.50
1.84
0.99
0.98
1.15
1.28
0.78
0.95
1.82
2.15
0.87
0.97
1.24
1.30
0.71
0.89
2.11
0.55
0.90
0.98
1.15
1.31
0.92
1.95
2.58
0.82
0.94
0.75
0.93
1.10
1.15
1.28
1.46
activity of the chlorosilylolefin double bond.
Table 2 lists the results of competitive chlorination of
1,2-dichloroethylene and 1-silyl-2-chloroethylenes,
as well as 1-silyl-2-chloro- and 1,2-disilylethylenes.
As seen from the table, substitution by methyl of even
one chlorine atom at silicon much affects the relative
activities of chloro- and silyl-substituted olefins and
almost equalizes the effects of the silyl group and
chlorine atom (Table 2, run no. 2). Further methyl
substitution for chlorine renders silyl-substituted
chloroolefins much more reactive than 1,2-dichloro-
ethylene (Table 2, run nos. 3 and 4). The same pattern,
while less pronounced, is observed for the 1-silyl-2-
chloro- and 1,2-disilylethylene pairs (Table 2, run
nos. 5 8).
At the same time, we found that chlorination of
adduct XI yields, along with expected substitutive
chlorination products, much decomposition products.
Cl2
Me2ClSiCHCl CHCl2
Me2SiCl2 + ClHC=CHCl
9% 8%
XI
+ Me2ClSiCCl2 CHCl2 + Me2ClSiCHCl CCl3
14% 15%
+ Me2ClSiCCl2 CCl3.
6%
Obviously, further reaction of adduct XI with
chlorine occurs by two directions: (a) more profound
(substitutive) chlorination and (b) Si C bond fission
to give the above decomposition products.
To find out decomposition pathways, we studied
in more detail chlorination of Me2ClSiCH=CHCl. As
shown earlier [1], the reaction gives decomposition
products along with adduct XI.
EXPERIMENTAL
1
The H NMR spectra were obtained on a Varian
Cl2
T-60A instrument for neat liquids and CCl4 solutions.
The internal reference was benzene. Gas chromato-
graphy was performed on an LKhM-72 chroma-
tograph with a thermal conductivity detector, column
2000 3 mm, packing 15% of PMS-20000 on Chro-
maton N-AW, carrier gas helium, linear oven tem-
perature programming at 12 deg/min.
Me2ClSiCH=CHCl
Me2ClSiCHCl CHCl2
XI
+ Me2SiCl2 + ClHC=CHCl.
It proved that individual adduct XI withstands
prolonged heating (130 140 C). On this basis one can
assume that decomposition accompanies formation of
this compound, most likely, from intermediate car-
bocation XII.
Chlorination of chlorosilylolefins. Gaseous
chlorine was barboted through 0.1 0.2 mol of un-
saturated compound at a rate of 3 4 g/h. In most cases,
the temperature of the reaction mixtures rose jump-
wise. The reaction completeness was controlled by
GLC. Chlorine was barboted until complete (or
almost complete) consumption of the starting chloro-
silylolefins. The products were isolated by vacuum
distillation.
Cl+ Cl
Me2ClSiCH CHCl
Me2ClSiCH=CHCl + Cl2
[Me2ClSiCHCl CHCl]+ + Cl
Me2SiCl2
XII
+ ClHC=CHCl.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 5 2003

710
LAKHTIN et al.
1,2-Bis(dichloromethylsilyl)dichloroethylene
1,2-Bis(chlorodimethylsilyl)dichloroethylene
(III). bp 91 C (2 mm), n2D0 1.5200, d420 1.4785. The
1H NMR spectrum contains two singlets at 0.95 and
0.97 ppm (5:3), characteristic of methyl groups at
silicon. These signals were assigned to the trans
(V). bp 122 C (20 mm), n2D0 1.5025, d420 1.2383. The
1H NMR spectrum contains two singlets at 1.12 and
1.10 ppm (5:4), characteristic of methyl groups at
silicon. These signals were assigned to the trans and
and cis isomers. Found, %: C 14.95; H 1.77; Cl 66.14; cis isomers. Found, %: C 25.84; H 4.15; Cl 51.04; Si
Si 17.17. C4H6Cl2Si2. Calculated, %: C 14.86; H 1.86;
Cl 65.94; Si 17.34.
19.67. C6H12Cl9Si2. Calculated, %: C 25.53; H 4.26;
Cl 50.35; Si 19.86.
1,2-Bis(dichloromethylsilyl)perchloroethane
1
REFERENCES
(IV). mp 33 35 C. The H NMR spectrum contains a
signal at 1.44 ppm, which is consistent with the
proposed structure. Found, %: C 12.33; H 1.57; Cl
71.79; Si 14.35. C4H6Cl8Si2. Calculated, %: C 12.18;
H 1.52; Cl 72.08; Si 14.21.
1. Lakhtin, V.G., Ryabkov, V.L., Kisin, A.V., Noso-
va, M.V., Polyakova, M.V., and Chernyshev, E.A., Izv.
Ross. Akad. Nauk, Ser. Khim., 1995, no. 11, p. 2256.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 5 2003