Process for preparing organohalosilanes utilizing copper halide-aluminum halide catalysts

This invention relates a process for the redistribution/disproportionation of organohalosilanes utilizing copper halide-aluminum halide complex catalysts.

FIELD OF THE INVENTION 
This invention relates to a novel process for the preparation of 
organohalosilanes utilizing copper halide-aluminum halide catalysts. In 
particular, this invention relates to a process for the redistribution, 
e.g., disproportionation, of organohalosilanes utilizing copper 
halide-aluminum halide complex catalysts. More particularly, this 
invention relates to a process for the preparation of triorganohalosilanes 
by the redistribution of diorganodihalosilanes in the presence of copper 
halide-aluminum halide complex catalysts. 
BACKGROUND OF THE INVENTION 
Organohalosilanes have found many uses in the chemical arts. By way of 
illustration, certain organohalosilanes, such as trimethylchlorosilane, 
are useful as silylating agents, polymer end-blockers and capping reagents 
in organic and pharmaceutical synthesis. Several processes for the 
preparation of organohalosilanes have been proposed. For example, 
methylchlorosilanes can be produced by the "direct reaction" of methyl 
chloride with a silicon-copper mass (see, e.g. U.S. Pat. No. 2,380,995). 
The direct reaction produces a mixture of organochlorosilanes (e.g. 
dimethyldichlorosilane and trimethylchlorosilane). Usually more 
dimethyldichlorosilane and less trimethylchlorosilane are produced by the 
direct reaction than are required commercially. 
Redistribution (e.g., disproportionation) methods are also known in the art 
for the preparation of organohalosilanes, particularly for converting 
excess dimethyldichlorosilane to needed trimethylchlorosilane. Some of 
these methods utilize aluminum catalysts and reactants, such as 
AlCl.sub.3, and other aluminum-containing materials. A silane 
redistribution reaction is a rearrangement of at least two different 
substituents which are attached to a silicon atom or atoms. One or more 
silanes having at least two substituents, such as CH.sub.3 or Cl, 
redistribute when these substituents exchange sites of bonding to silicon. 
The resulting silane or silanes still have a total of four substituents or 
atoms attached to the silicon atom, but in ratios different from that of 
the starting silane or silanes. A typical silane redistribution reaction 
can be illustrated by the following equation: 
##STR1## 
A silane disproportionation reaction is a type of silane redistribution 
reaction that occurs when a single silane yields two or more dissimilar 
silanes having substituents (i.e., CH.sub.3 Cl) in differing proportions 
from that of the initial starting silane. A silane disproportionation 
reaction can be illustrated by the following equation: 
##STR2## 
This position of thermodynamic equilibrium in the disproportionation of 
diorganodihalosilanes typically favors a high concentration of the 
diorganodihalosilane. For example, with dimethyldichlorosilane, the 
following equilibrium concentrations are observed at 350.degree. C. with 2 
weight percent AlCl.sub.3 : 
##STR3## 
(see Zemany et al, J. Amer. Chem. Soc., vol. 70, p. 4222 (1948); Golosova 
et al, Russ. J. Phys. Chem., vol 45, p. 460 (1971) Engl. Trans.). 
Disproportionation of diorganodihalosilanes without any catalyst or with 
the catalysts described by the prior art does not provide a practical 
commercial synthesis of triorganohalosilanes because equilibrium is 
attained too slowly or not at all. Consequently, a practical synthesis of 
triorganohalosilanes by the disproportionation of diorganodihalosilanes 
requires the use of a catalyst capable of accelerating the attainment of 
equilibrium. The use of SiH compounds and arylsilanes as co-catalysts with 
AlCl.sub.3 for this purpose is known (See U.S. Pat. Nos. 2,786,861 and 
3,793,357). 
U.S. Pat. No. 2,717,257 describes the use of alkali metal 
halogen-aluminates of the general formula, MAlX.sub.4, wherein M is an 
alkali metal and X is a halogen, as catalysts for the redistribution of 
organohalosilanes. 
Morozov et al (Russ. J. Gen. Chem. vol. 41, p. 1275 (1971); vol. 39, p. 
2234 (1969) Engl. Trans.) report that the disproportionation of 
dichlorodimethylsilane is facilitated by the addition of NaAlCl.sub.4 to a 
fixed bed of silicon-copper contact mass in the presence of active methyl 
chloride molecules on the catalyst surface. 
U.S. Pat. No. 2,647,136 states that aluminum chloride was the only catalyst 
found to accelerate the redistribution of methylchlorosilanes and that the 
other common Lewis acid catalysts, such as BCl.sub.3, ZnCl.sub.2, 
FeCl.sub.3 and CuCl, had no perceptible effect on the course of the 
redistribution reaction. 
The use of organoaluminum compounds as catalysts in methylchlorosilane 
redistribution and disproportionation reactions, in general, often results 
in pyrophoric, potentially explosive, and readily hydrolyzable 
organoaluminum by-products which must be disposed via lixiviation with 
water or alkali. This can be extremely hazardous because of the attendant 
hydrolysis of methylchlorosilanes to yield hydrogen chloride. Aluminum 
trichloride has appreciable solubility in methylchlorosilane mixtures 
which can produce separation and purification problems. Plugging problems 
in transport lines and distillation columns are usually concomitant with 
its use. When aluminum trichloride is utilized in conjunction with certain 
co-catalysts described in the prior art, there is the possibility of 
product contamination or loss of catalyst by volatization. 
Complexes comprising copper halides and aluminum halides are known (see, 
e.g., Schlapfer, et al, Inorganic Chem., vol. 17, No. 6, p. 1623 (1978); 
and U.S. Pat. Nos. 3,651,159; 3,647,843; and 3,592,865). These complexes 
have been utilized in various processes, e.g. in reactions involving the 
alkylation or halogenation of hydrocarbons (see U.S. Pat. Nos. 3,846,503; 
3,846,504; 3,420,908; and 3,935,288). However, prior to the present 
invention, complexes of aluminum halide and copper halide were not 
utilized in reactions involving the redistribution of organohalosilanes. 
Accordingly, it is an object of the present invention to provide a novel 
process for the preparation of organohalosilanes utilizing copper 
halide-aluminum halide complex catalysts. 
In particular, it is an object of the present invention to provide a novel 
process for the redistribution (e.g., disproportionation) of 
organohalosilanes utilizing a copper halide-aluminum halide complex 
catalyst. 
More particularly, it is an object of this invention to provide a novel 
process for the preparation of triorganohalosilanes by the catalytic 
disproportionation of diorganodihalosilanes utilizing a copper 
halide-aluminum halide complex catalyst. 
A further object of this invention is to provide a process for the 
redistribution of organohalosilanes which does not produce hazardous 
by-products, involve soluble catalysts, produce product contamination or 
lose catalyst through volatization. 
DESCRIPTION OF THE INVENTION 
This invention relates to a process for effecting the redistribution of at 
least one organic group bonded to a silicon atom by a silicon to carbon 
bond and at least one halogen atom bonded to a silicon atom which process 
comprises: 
(1) forming a reaction mixture of 
(a) a first silane or first mixture of silanes containing at least one 
organic group bonded to a silicon atom by a silicon to carbon bond and at 
least one halogen atom bonded to a silicon atom; and 
(b) a catalytic amount of AlX.sub.3 and CuX.sub.n complex wherein n is 1 or 
2 and X is a halogen atom; and 
(2) maintaining the reaction mixture at a temperature and pressure at which 
said group and atom in (1)(a) redistribute to form a second silane or a 
second mixture of silanes different from the first silane or first mixture 
of silanes. 
For the purposes of this invention the catalytically effective complex of 
AlX.sub.3 and CuX.sub.n (hereinafter also referred to as the "catalyst 
complex") is any complex of AlX.sub.3 and CuX.sub.n which can accelerate 
the rate at which the redistribution is effected and is meant to encompass 
complexes formed from mixtures of AlX.sub.3 and CuX, mixtures of AlX.sub.3 
and CuX.sub.2, and mixtures of AlX.sub.3, CuX and CuX.sub.2. Preferably 
all the AlX.sub.3 and CuX.sub.n in the catalyst mixture will be complexed 
and no free (i.e., uncomplexed) AlX.sub.3 will be present. Complete 
complexing can occur when the molar ratio of CuX.sub.n to AlX.sub.3 in the 
catalyst mixture is from about 0.5:1 to about 3:1. The complex formed when 
the molar ratio of CuX.sub.n to AlX.sub.3 is about 0.5:1 is preferred. 
Complete complexing of the AlX.sub.3 and CuX.sub.n, although desirable, is 
not necessary for a mixture of AlX.sub.3 and CuX.sub.n to produce a 
catalytically effective complex useful in the process of this invention. 
The catalyst mixture useful in producing the catalyst complex in the 
process of this invention can comprise a molar ratio of CuX.sub.n to 
AlX.sub.3 of at least about about 0.05:1, preferably from about 0.25:1 to 
0.6:1 and most preferably about 0.5:1. The concentration of the total 
catalyst complex can be as low as 0.1% by weight, based on the total 
weight of the silane reactant(s) in the reaction complex. Higher 
concentrations of the catalyst complex will increase the rate of 
redistribution and decrease the overall reaction time. The upper limit on 
the concentration of the catalyst complex is not critical and would be 
determined largely by commercial and economic considerations. As a 
practical matter, a concentration of catalyst complex of less than 10%, 
generally between 5-10%, by weight based on the total weight of the silane 
reactant(s) in the redistribution reaction mixture, is preferred. 
The active catalyst complex can be prepared in situ by adding the 
ingredients of the catalyst mixture, i.e. CuX.sub.n and AlX.sub.3, to the 
redistribution reaction mixture and exposing the resultant reaction 
mixture to the appropriate temperature and pressure conditions to effect 
the desired redistribution. Alternatively the active catalyst complex may 
be preformed by heating the ingredients of the catalyst mixture together, 
e.g. in a sealed ampoule, and then transferring the catalyst mixture so 
formed to the redistribution reaction mixture. 
The CuX, CuX.sub.2, and AlX.sub.3 used in the process of this invention 
should all be anhydrous materials to avoid side reactions between the 
water of hydration and the organohalosilanes. Additionally, whether the 
active catalyst complex useful in the process of this invention is 
preformed or formed in situ, its subsequent handling should be under 
anhydrous, inert atmospheric conditions in order to avoid hydrolysis and 
oxidation. Such anhydrous, inert atmospheric conditions are also necessary 
if reuse of the active catalyst complex without loss of catalytic activity 
is desired. 
The process of this invention can be conducted in the presence of an 
organic solvent, if desired, provided that the presence of the solvent 
does not have a deleterious effect on the redistribution reaction. For 
example, branched aliphatic hydrocarbons, such as 2,5-dimethyl hexane, can 
be used as solvents because they do not interfere with the redistribution 
reaction whereas certain aromatic solvents, such as toluene, are not 
acceptable solvents because they could inhibit the catalytic activity of 
the CuX.sub.n /AlX.sub.3 catalyst complex. 
The manner in which the process of this invention can be practiced will 
vary depending on the choice of silane or mixture of silanes in the 
redistribution reaction mixture. For example, as described below, the 
temperature and pressure requirements can vary significantly from those 
necessary for the disproportionation of a diorganodihalosilane to those 
necessary for the redistribution of a mixture of organohalosilanes. 
A preferred embodiment of this invention relates to a process for the 
catalytic disproportionation of a diorganodihalosilane of the formulas 
EQU R.sub.2 SiX.sub.2 [Formula ( 1)] 
wherein R is alkyl or aryl and X is halogen, which comprises contacting the 
diorganodihalosilane with a catalytic amount of a complex of AlX.sub.3 and 
CuX.sub.n, wherein n is 1 or 2, and X is as defined above, at a 
temperature greater than 200.degree. C. and under superatmospheric 
pressure. 
The process of this preferred embodiment of this invention is conducted 
under superatmospheric pressure, preferably from about 400-750 psi, more 
preferably from about 450-550 psi, and preferably under autogenous 
conditions. The reaction temperature of the process of this preferred 
embodiment of this invention can be varied depending on such factors as 
the particular diorganodihalosilane employed, the pressure utilized, etc. 
In general, the reaction temperature must be greater than about 
200.degree. C., preferably between about 250.degree. C. to about 
350.degree. C. and most preferably between about 250.degree. C. to about 
300.degree. C. The reaction time will vary (e.g. from about 1 to about 10 
hours), depending on factors such as catalyst concentration, reaction 
temperature, etc., but, in general, when the reaction temperature is 
between about 250.degree. C.-300.degree. C. and the catalyst complex 
concentration in the disproportionation reaction mixture is about 5-10% by 
weight based on the weight of the diorganodihalosilane utilized, using a 
catalyst mixture wherein the molar ratio of CuX.sub.n /AlX.sub.3 is about 
0.5:1, the reaction time will be about 4-8 hours. 
When the disproportionation reaction of the process of this preferred 
embodiment of this invention is completed, the triorganohalosilane 
produced can be distilled from the crude reaction product. If reuse of the 
CuX.sub.n /AlX.sub.3 catalyst complex is desired, a new supply of 
diorganodihalosilane need only be added to the residue of the distillation 
and the resultant reaction mixture subjected to the desired appropriate 
reaction conditions selected from those outlined above. 
As stated above, the process of this invention can also be utilized for the 
redistribution of mixtures of organohalosilanes. Accordingly, another 
preferred embodiment of this invention relates to a process for the 
catalytic redistribution of a mixture of organohalosilanes having the 
formulas: 
EQU R.sub.m SiX.sub.4-m [Formula ( 2)] 
and 
EQU R.sub.p SiHX.sub.3-p [Formula ( 3)] 
wherein R and X are as defined above, m is 1 to 4 inclusive and p is 1 to 3 
inclusive, which comprises contacting the mixture of organohalosilanes 
with a catalytic amount of a complex of AlX.sub.3 and CuX.sub.n. The 
reaction conditions described above for the disproportionation of 
diorganodihalosilanes can be used for this redistribution reaction as 
well, although this redistribution reaction can be conducted at 
temperatures as low as room temperature or higher and at atmospheric or 
super-atmospheric pressure. 
The halogen represented by X in Formulas (1), (2) and (3) above is 
preferably the same in the organohalosilane and in the complex of 
AlX.sub.3 and CuX.sub.n, i.e., if X is Cl in the organohalosilane, then 
the complex should comprise AlCl.sub.3 and CuCl.sub.n. This is desirable 
to avoid obtaining products of the redistribution with different halogen 
substituents. Preferably R is C.sub.1 -C.sub.4 alkyl, most preferably 
methyl, and X is preferably chlorine. 
The following Examples are presented to illustrate the process of this 
invention. 
The terms and abbreviations used in the Examples have the following 
meanings. 
______________________________________ 
ABBREVIATION MEANING 
______________________________________ 
GC Gas chromatography 
GC/MS Gas chromatography/mass 
spectrometry 
.degree.C. Degree Celsius 
.degree.K. Degree Kelvin 
T .degree.K. Temperature in degrees Kelvin 
cm centimeter 
cm.sup.-1 reciprocal centimeter 
wt % weight percent 
ml milliliter 
gm gram 
Kcal Kilocalorie 
psig pounds per square inch 
min minute 
hr hour 
Temp. Temperature 
TC HSiCl.sub.3 
MD CH.sub.3 SiHCl.sub.2 
M (CH.sub.3).sub.3 SiCl 
T CH.sub.3 SiCl.sub.3 
D (CH.sub.3).sub.2 SiCl.sub.2 
Q (CH.sub.3).sub.4 Si 
DM (CH.sub.3).sub.2 SiHCl 
______________________________________ 
STARTING MATERIALS 
The AlCl.sub.3, CuCl and CuCl.sub.2 used in the following Examples were 
commercial compounds. Commercial CuCl can contain up to about 3 wt % 
CuCl.sub.2. (CH.sub.3).sub.2 SiCl.sub.2 was reagent grade material 
typically of about 99.7 wt % purity.

EXAMPLE 1 
This example shows that the mixture of copper chloride and aluminum 
chloride reacts to form new complex species different from the starting 
chlorides. 
A. 0.43 gm CuCl (0.0043 mole) and 1.11 gm AlCl.sub.3 (0.0083 mole) were 
mixed together in a thick-walled glass ampoule in a glove-bag filled with 
dry nitrogen. The ampoule was then evacuated, sealed in a flame and 
subsequently placed in a fluidized sand bed of 300.degree. C. for 15 
minutes. On removal from the bed, the ampoule contained a dark colored 
liquid, which crystallized to a gray solid. 
B. A mixture of 0.75 gm CuCl.sub.2 (0.0056 mole) and 1.42 gm AlCl.sub.3 
(0.011 mole) was prepared in A. above and reacted to give yellow crystals. 
Each solid sample, still within the sealed ampoule, was then analyzed by 
Raman Spectroscopy. The principal bands observed are set forth in Table 1 
along with comparative data for solid AlCl.sub.3. Solid CuCl has no Raman 
spectrum. The results show that while the solid reaction product samples 
and solid AlCl.sub.3 sample have Raman bands at 305-307 cm.sup.-1 and 
168-170 cm.sup.-1, the intensity ratios of the bands are different for the 
three samples. The relative intensity of the band at 307 cm.sup.-1 to that 
at 168 cm.sup.-1 in the CuCl/AlCl.sub.3 sample is 1.54, while the 
corresponding ratio for solid AlCl.sub.3 sample is 3.22. The 348 cm.sup.-1 
band in the spectrum of the CuCl/AlCl.sub.3 sample is very intense and has 
no counterpart in the AlCl.sub.3 spectrum. It is apparent that the solid 
reaction product of CuCl and AlCl.sub.3 is different from either of the 
starting materials and gives rise to the Raman vibrations at 168 
cm.sup.-1, 307 cm.sup.-1 and 348 cm.sup.-1. Comparison of the data for 
the CuCl/AlCl.sub.3 sample and the CuCl.sub.2 /AlCl.sub.3 sample in Table 
1 shows that different complexes are formed. 
TABLE 1 
______________________________________ 
Raman Bands of AlCl.sub.3, CuCl.sub.2 plus AlCl.sub.3 and CuCl 
plus AlCl.sub.3 (Molar Ratio CuCl.sub.n /AlCl.sub.3 = 0.5) 
Solid AlCl.sub.3 
Solid CuCl.sub.2 + AlCl.sub.3 
Solid CuCl + AlCl.sub.3 
______________________________________ 
115 cm.sup.-1 (w) 
110 cm.sup.-1 (sh) 
110 cm.sup.-1 (sh) 
170 (m) 170 (m) 168 (m) 
196 (w) 93 (vs) 
255 (w) 268 (vs) 
306 (vs) 305 (w) 307 (s) 
352 (m) 348 (vs) 
395 (m) 
485 (w) 
______________________________________ 
Note: 
Abbreviations in parenthesis refer to the relative intensities of the 
Raman vibration bands. They have the following meanings: 
sh = shoulder, 
w = weak, 
m = medium, 
s = strong, 
vs = very strong 
EXAMPLE 2 
This example illustrates the effect of increasing CuCl levels on the yield 
of (CH.sub.3).sub.3 SiCl and CH.sub.3 SiCl.sub.3 from the 
disproportionation of CH.sub.2 SiCl.sub.2 at 264.degree. C. with 5 wt % 
AlCl.sub.3. 
Eight separate experiments were conducted (see Table 2 below). In each 
experiment, 0.40-0.45 mole (CH.sub.3).sub.2 SiCl.sub.2 was placed in 300 
ml stainless steel autoclave along with a mixture of 5 wt % AlCl.sub.3 and 
0-5 wt % CuCl (percentages based on the weight of (CH.sub.3).sub.2 
SiCl.sub.2 used). A mixture of AlCl.sub.3 and CuCl was weighed out in a 
nitrogen-filled glove bag, shaken together and then transferred to the 
autoclave. The sealed autoclave was rocked to mix the reactants, and 
heated to 264.degree. C. for 5 hours. The pressure attained was 500-550 
psig. After cooling the autoclave, the contents of the autoclave were 
emptied into a dried, nitrogen-flushed, weighed container for subsequent 
analysis by GC and GC/MS. The composition of the reaction mixtures for the 
eight experiments is set forth in Table 2. From the literature [J. Amer. 
Chem. Soc., vol. 70, 4222 (1948); Russ J. Phys. Chem., vol. 45, No. 4, 460 
(1971 ], it can be calculated that the equilibrium concentration of 
(CH.sub.3).sub.3 SiCl at 264.degree. C. is 8.35 wt %. The results in Table 
2 below show that the yield of (CH.sub.3).sub.3 SiCl varied with the molar 
ratio of CuCl to AlCl.sub.3 but that complexes of CuCl and AlCl.sub.3 
(Examples 2B to 2G) were superior catalysts compared to AlCl.sub.3 alone 
(Example 2A). CuCl alone had no catalytic effect on the disproportionation 
of (CH.sub.3).sub.2 SiCl.sub.2 (Example 2H). 
TABLE 2 
______________________________________ 
The effect of CuCl on the Disproportiona- 
tion of (CH.sub.3).sub.2 SiCl.sub.2 ("D") by AlCl.sub.3 at 264.degree. 
C., 
520-550 psig to produce methyltrichlorosilane ("T") 
and trimethylchlorosilane ("M") 
Molar 
Ex- Ratio M T 
am- Moles AlCl.sub.3 
CuCl CuCl Wt Wt D 
ple D Wt % Wt % AlCl.sub.3 
% % Wt % 
______________________________________ 
2A 0.45 5.04 0 0 1.45 3.27 95.28 
2B 0.45 5.02 1.04 0.28 1.64 5.46 92.90 
2C 0.46 5.01 1.86 0.50 4.80 9.70 85.50 
2D 0.43 5.02 2.15 0.58 4.50 10.0 85.50 
2E 0.42 5.01 2.47 0.66 3.15 7.16 89.69 
2F 0.43 5.04 3.74 1.00 2.73 6.41 90.86 
2G 0.41 5.06 5.06 1.35 1.89 5.11 93.00 
2H 0.42 0 4.94 0 0 0 100.00 
______________________________________ 
EXAMPLE 3 
This example illustrates the effect of temperature and CuCl/AlCl.sub.3 
molar ratio on the yield of (CH.sub.3).sub.3 SiCl and CH.sub.3 SiCl.sub.3 
by the disproportionation (CH.sub.3).sub.2 SiCl.sub.2. The data permit the 
computation of activation energies for the catalytic disproportionation 
reactions with AlCl.sub.3 alone and a CuCl/AlCl.sub.3 complex with a molar 
ratio of 0.5: 1. 
Ten separate experiments (3A to 3J) were conducted and the conditions and 
results are shown in Table 3 below. The procedure and equipment used were 
the same as those described in Example 2, except that the molar amount of 
(CH.sub.3).sub.2 SiCl.sub.2 used was between 0.43-0.55 mole, the 
CuCl/AlCl.sub.3 molar ratios were held to 0-1.00 and the temperature was 
varied from 264.degree. C.-323.degree. C. The time at the stated 
temperature was five hours in each case. The experimental data are set 
forth in Table 3. 
The yield of (CH.sub.3).sub.3 SiCl increased between 264.degree. C. and 
323.degree. C. at each of the molar ratios studied. At 323.degree. C., the 
content of (CH.sub.3).sub.3 SiCl in the reaction mixture was 8.19 wt % at 
CuCl/AlCl.sub.3 molar ratio of 0.26 and 0.50. This value was 85% of the 
equilibrium concentration (9.6 wt %) calculable from the literature 
references in Example 2. 
The efficacy of a catalyst in effecting disproportionation reactions can be 
measured by determining the rate of approach to equilibrium as well as the 
yield of products relative to the equilibrium values at the temperature of 
the reactions. All the reactions were run for 5 hours at the stated 
temperatures, so the quantity of (CH.sub.3).sub.3 SiCl formed is a direct 
indication of the rate of approach to equilibrium. Accordingly, a plot of 
log (M wt %) versus 1/T.degree.K. is an Arrhenius plot [see Benson, The 
Foundation of Chemical Kinetics, McGraw-Hill Book Co., N.Y. (1960), pp. 
66-67] from which the activation energy of the reaction can be calculated. 
A lower activation energy denotes a faster reaction and hence more 
efficient catalysis. 
An Arrhenius plot for the experiments (3A, 3B, 3C) wherein the 
CuCl/AlCl.sub.3 molar ratios were 0.5-0.6 gave an activation energy of 
6.53 kcal per mole. The corresponding plot for the AlCl.sub.3 -catalyzed 
reaction at 264.degree. C.(537.degree. K.) and 300.degree. C.(574.degree. 
K.), examples 3I and 3J, respectively gave an activation energy of 21.1 
kcal per mole. The disproportionation reactions catalyzed by complexes of 
CuCl and AlCl.sub.3, therefore, proceed at a much faster rate than the 
reactions using AlCl.sub.3 alone. A rate increase of about 10.sup.6 can 
result from using a CuCl/AlCl.sub.3 mixture with a molar ratio of 0.5 
instead of using AlCl.sub.3 alone. 
TABLE 3 
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The effect of Temperature and CuCl/AlCl.sub.3 
on (CH.sub.3).sub.2 SiCl.sub.2 Disproportionation 
Ex- M T D 
am- Temp. Moles AlCl.sub.3 
Molar Ratio 
Wt Wt Wt 
ple .degree.C. 
D Wt % CuCl/AlCl.sub.3 
% % % 
______________________________________ 
3A 264 0.43 5.02 0.58 4.50 10.0 85.50 
3B 304 0.54 5.01 0.53 6.89 14.99 
78.12 
3C 322 0.45 5.05 0.50 8.19 17.99 
73.82 
3D 264 0.43 5.04 1.00 2.73 6.41 90.86 
3E 300 0.55 5.02 1.00 6.37 14.19 
79.45 
3F 264 0.45 5.02 0.28 1.64 5.46 92.90 
3G 323 0.44 5.05 0.26 8.19 17.03 
74.18 
3H 300 0.55 5.06 0.105 5.51 11.26 
83.23 
3I 264 0.45 5.04 0 1.45 3.27 95.28 
3J 300 0.44 5.14 0 5.02 11.75 
83.23 
______________________________________ 
EXAMPLE 4 
This example illustrates the uniqueness of complexed CuCl and CuCl.sub.2 
compared with powdered copper, FeCl.sub.3, SnCl.sub.2, NaCl and AgCl, in 
promoting the AlCl.sub.3 -catalyzed disproportionation of (CH.sub.3).sub.2 
SiCl.sub.2. 
Examples 4A thru 4F (see Table 4 below) were performed in the 300 ml 
rocking autoclave according to the procedure of Example 2, except that 
additives other than CuCl were employed. The quantities of FeCl.sub.3 and 
CuCl.sub.2 were chosen so as to give molar ratios of 0.5 with AlCl.sub.3. 
In example 4C with SnCl.sub.2 as additive, the AlCl.sub.3 concentration 
was 3 wt % and the SnCl.sub.2 /AlCl.sub.3 molar ratio 0.47. 
Examples 4G thru 4J (see Table 4 below) were performed in a 45 ml autoclave 
heated in a fluidized sand bath. The reagents [(CH.sub.3).sub.2 
SiCl.sub.2, AlCl.sub.3 and additive] were charged to the autoclave in the 
nitrogen-filled glove bag as described in Example 2. The autoclave was 
then sealed and heated in the sand bath at 265.degree. C. That temperature 
was maintained for 4 hours. Comparative experiments with AlCl.sub.3 alone 
and AlCl.sub.3 plus CuCl (molar ratio CuCl/AlCl.sub.3 =0.5) under these 
conditions are shown in Table 4 as Examples 4I and 4J. 
The data showed that powdered copper, SnCl.sub.2, FeCl.sub.3, NaCl and AgCl 
did not promote the AlCl.sub.3 catalysis of (CH.sub.3).sub.2 SiCl.sub.2 
disproportionation whereas complexed CuCl.sub.2 and CuCl did. 
TABLE 4 
__________________________________________________________________________ 
The effect of Cu, CuCl.sub.2, SnCl.sub.2, FeCl.sub.3, NaCl, AgCl 
on the Disproportionation of (CH.sub.3).sub.2 SiCl.sub.2 by AlCl.sub.3 
at 264.degree. C. and 300.degree. C. 
Moles 
AlCl.sub.3 
Additive 
Temp. 
M T D 
Example 
Additive 
D Wt % 
Wt % .degree.C. 
Wt % 
Wt % 
Wt % 
__________________________________________________________________________ 
4A None 0.45 
5.04 
0 264 1.45 
3.27 
95.28 
4B Powdered Cu 
0.55 
5.04 
2.13 264 1.73 
3.35 
94.92 
4C SnCl.sub.2 
0.47 
3.0 2.0 300 3.30 
6.87 
89.83 
4D CuCl.sub.2 
0.52 
5.01 
2.59 300 6.78 
17.54 
75.67 
4E FeCl.sub.3 
0.46 
5.01 
3.24 300 5.00 
13.14 
81.86 
4F None 0.44 
5.14 
0 300 5.51 
11.26 
83.23 
4G NaCl 0.058 
5.04 
1.84 265 1.01 
3.29 
95.70 
4H AgCl 0.058 
5.04 
2.67 265 1.05 
3.30 
95.65 
4I None 0.058 
5.04 
0 265 1.09 
3.43 
95.48 
4J CuCl 0.058 
5.04 
1.8 265 4.76 
10.84 
84.40 
__________________________________________________________________________ 
EXAMPLE 5 
The four experiments (5A-5D) of this example were conducted separately in a 
45 ml autoclave using the procedure described in Example 4G through 4J. 
Each experiment (5A-5D) was conducted with 7.5 gm (CH.sub.3).sub.2 
SiCl.sub.2 and the respective stated quantities of AlCl.sub.3 and CuCl set 
forth in Table 5 below. 
The data in Table 5 below demonstrates that the yield of (CH.sub.3).sub.3 
SiCl from (CH.sub.3).sub.2 SiCl.sub.2 disproportionation with 
CuCl--AlCl.sub.3 catalyst mixture of 265.degree. C. for 1, 2 and 4 hours 
was greater than the yield from the disproportionation catalyzed by 
AlCl.sub.3 alone at 300.degree. C. for 1 hour. 
TABLE 5 
__________________________________________________________________________ 
(CH.sub.3).sub.2 SiCl.sub.2 Disproportionation at Short 
Reaction Times and Low Catalyst Concentrations 
Moles 
AlCl.sub.3 
CuCl 
Temp. 
Time 
Example 
D Wt % 
Wt % 
.degree.C. 
Hr M Wt % 
T Wt % 
D Wt % 
__________________________________________________________________________ 
5A 0.058 
4.93 
1.75 
265 1 0.62 3.18 96.20 
5B 0.058 
5.08 
1.80 
265 2 2.07 3.83 94.22 
5C 0.058 
0.50 
0.19 
265 4 0.53 3.40 95.51 
5D 0.058 
5.08 
0 300 1 -- -- 100.00 
__________________________________________________________________________ 
EXAMPLE 6 
This example demonstrates the reusability of the catalyst complex of this 
invention. 
For Example 6A, 55.6 gm (CH.sub.3).sub.2 SiCl.sub.2 was reacted in the 
presence of a complex formed from a mixture of 3.2 gm AlCl.sub.3 and 1.2 
gm CuCl in a 300 ml autoclave at 310.degree. C. using the procedure of 
Example 2. The molar ratio of CuCl to AlCl.sub.3 was 0.5. After 5.2 hours 
at 310.degree. C. the autoclave was cooled to 100.degree. C., which is 
below the melting point of the CuCl--AlCl.sub.3 catalyst but above the 
normal boiling points of the methylchlorosilanes in the reaction product. 
The valved outlet of the autoclave was connected to an evaculated cooled 
(with dry-ice and isopropanol) 150 ml stainless steel sample cylinder. On 
opening the valves of the autoclave and the cylinder, the 
methylchlorosilane mixture distilled from the autoclave into the sample 
cylinder and the catalyst complex remained in the autoclave. 38.7 gm of 
liquid was so transferred. Thereafter the autoclave and sample cylinder 
were disconnected and the sample cylinder warmed to room temperature. Any 
residual vacuum was released under nitrogen prior to analysis of the 
reaction product. 
For Example 6B fresh (CH.sub.3).sub.2 SiCl.sub.2 (44.0 gm) was placed in 
another 150 ml stainless steel sample cylinder with a valve attached at 
each end. One end of the cylinder was connected to the valved inlet of the 
autoclave (containing the catalyst complex from example 6A above) and the 
other end to a nitrogen source pressurized to 30 psig. The 
dimethyldichlorosilane was transferred to the autoclave by first opening 
the cylinder valve distal from the autoclave (i.e., to pressurize the 
cylinder which contained the dimethyldichlorosilane), followed by opening 
the valve proximal to the autoclave and finally opening the autoclave 
valve itself. After the transfer the valves were closed and the autoclave 
disconnected from the sample cylinder. The autoclave was reheated to 
310.degree. C. and maintained at that temperature for 4.1 hours. 51.9 gm 
of liquid product was recovered by vacuum transfer from the cooled 
(100.degree. C.) autoclave as described above. Product analysis of the two 
disproportionation experiments is shown in Table 6. 
The data in Table 6 below demonstrates that the catalyst complex used in 
the process of this invention is reusable. (CH.sub.3).sub.3 SiCl and 
CH.sub.3 SiCl.sub.3 were also produced in Example 6B in good yields; the 
catalyst in Example 6A was the same catalyst used in Example 6B, and no 
additional CuCl or AlCl.sub.3 was added to Example 6B. 
TABLE 6 
______________________________________ 
Reuse of CuCl--AlCl.sub.3 Catalyst Complex in the 
Disproportionation of (CH.sub.3).sub.2 SiCl.sub.2 at 310.degree. C. 
HCl MD M T D 
Example Wt % Wt % Wt % Wt % Wt % 
______________________________________ 
6A 0.26 0.44 7.48 15.20 76.62 
6B 1.17 2.15 8.47 15.07 73.15 
______________________________________ 
EXAMPLE 7 
This example illustrates the redistribution of (CH.sub.3).sub.3 SiCl and 
CH.sub.3 SiCl.sub.3 by CuCl--AlCl.sub.3 catalyst complex. 
CH.sub.3 SiCl.sub.3 (2.9 gm, 0.0194 mole) and (CH.sub.3).sub.3 SiCl (2.15 
gm, 0.0198 mole) were charged to a 45 ml autoclave along with a mixture of 
0.376 gm AlCl.sub.3 and 0.14 gm CuCl using the procedure in Example 4G and 
4J. The sealed autoclave was then heated to 265.degree. C. in a fluidized 
sand bath and maintained there for 4 hours. Thereafter the autoclave was 
cooled to room temperature and its contents subsequently analyzed by gc. 
The analytical data (see Table 7) show that the desired product of the 
redistribution, i.e. (CH.sub.3).sub.2 SiCl.sub.2, accounted for over 50 wt 
% of the reaction end product. 
TABLE 7 
______________________________________ 
Redistribution of (CH.sub.3).sub.3 SiCl and CH.sub.3 SiCl.sub.3 by 
CuCl--AlCl.sub.3 (molar ratio 0.5) at 265.degree. C., 370 psig 
M T D 
Example Wt % Wt% Wt % 
______________________________________ 
7A 20.68 26.09 53.63 
______________________________________ 
EXAMPLE 8 
This example illustrates that the CuCl--AlCl.sub.3 complexes catalyze the 
redistribution of methylchlorosilanes even at 23.degree. C. 
The catalyst was prepared by heating 1.11 gm AlCl.sub.3 and 0.43 gm CuCl in 
an evacuated glass ampoule 300.degree. C. as described in Example 1A. The 
solid was retrieved by breaking the ampoule in a N.sub.2 -filled glove 
bag. The 1.54 gm catalyst complex having a CuCl/AlCl.sub.3 molar ratio of 
0.5 was added to 22 gm of a methylchlorosilane mixture containing 43.98% 
(CH.sub.3).sub.4 Si, 8.91% (CH.sub.3).sub.2 SiHCl and 46.97% 
(CH.sub.3).sub.2 SiCl.sub.2 in a 250 ml 3-neck round bottom flask. A 
reflux condenser was affixed to one neck, a thermometer to another and a 
serum cap to the third. The serum cap facilitated periodic sampling of the 
magnetically stirred reaction mixture for gc analysis. Temperature was 
maintained at 23.degree. C. 
The results (see Table 8 below) demonstrate that (CH.sub.3).sub.3 SiCl was 
formed from the redistribution. 
TABLE 8 
______________________________________ 
Redistribution of (CH.sub.3).sub.4 Si("Q") 
(CH.sub.3).sub.2 SiHCl ("DM") and 
(CH.sub.3).sub.2 SiCl.sub.2 ("D") by 
CuCl--AlCl.sub.3 (molar ratio = 0.5) 
at 23.degree. C. 
Time, Hr 
Q wt % DM wt % M wt % D wt % 
______________________________________ 
0 43.98 8.91 0.14 46.97 
0.5 42.81 8.66 2.22 46.31 
1.0 42.91 8.48 2.92 45.70 
1.5 43.98 8.81 3.28 43.93 
2.0 41.65 8.39 3.33 47.81 
3.0 41.52 8.61 3.46 46.40 
______________________________________