Note: Descriptions are shown in the official language in which they were submitted.
1 327 0~
RD-17,758
RD-17,758
sI~yLaTIo~ NETHOD
BACXGRO~ND OF ~ INVEN~IO~
In United States Patent Number 4,709,050,
issued Novemher 24, 1987, SILYLATION METHOD AND ORGANIC
SILANES MADE THEREFROM, there is described a method for
silylating aromatic acylhalide with halogenated polysilane
in the presence of an effective amount of a transition
metal catalyst. As shown by Yamamoto et al., Tetrahedron
Letters, 1653 (1980) activated aromatic acylhalide, such as
para-nitrobenzoylchloride, can be converted to the
corresponding aromatic silane with a loss of carbon
monoxide as a result of a decarbonylation reaction
utilizing hexamethyldisilane as the silylating reactant.
It was found, however, that the silylation o~ the aromatic
nucleus using hexamethyl disilane, resulted in only a minor
amount of the desired aromatic silane, such as a
paranitrophenyltrim~thylsilane, whll~ the major product was
: the corresponding aromatic silylketnne.
In my U.S. Patent No. 4,709,054, issued
November 24, 1987, and assigned to General Electric
Company, there is taught that i~ halogenated polysilane of
the formula,
R(~i )n~i-X , ( 1 )
-`` 1 3~70~
RD-17,758
is reacted with aromatic acylhalide of the formula,
O
Rl[CX]m , (2)
in the presence of an ef~ective amount of a transition
metal catalyst, a wide variety of aromatic silylation
reaction products can be obtained at high yields resulting
in the production of nuclear-bound carbon-silicon bonds,
where X is a halogen radical, R is selected from X,
hydrogen, C(1-13) monovalent hydrocarbon radicals,
substituted C(1-13) monovalent hydrocarbon radicals, and
divalent -0-, S- radicals and mixtures thereof which can
form 9siosi- and -sissia connecting groups, R1 is a C(6_20)
monovalent or polyvalent aromatic organic radical, n is an
integer equal to 1 to 50 incl~sive, and m is an integer
equal to 1 to 4 inclusive.
Although the method o~ U.S. Patent No.
4,709,0~4 provides for the production of organic silanes
: ~ and silarylenes at high yields, it has been found difficult
to recycle, regeneratP or salvage transition metal catalyst
; values from thP reaction mixture.
In addition, in instances where halogenated
;20 polysilane of the formula is used as a reactant,
~X ) 2 ~ A1
n l
2 -
`` 1 3270l~
RD-17,758
where R, X and n are as previously defined, reaction can
occur between the halogenated polysilane and the transition
metal catalyst if a phosphine cocatalyst is used, resulting
in reduced yield of nuclear-bound carbon-silicon bonds.
The present invention is based on my discovery
that a wide variety of silylated aromatic reaction products
having one or more nuclear-bound silicon atoms joined to an
aromatic nucleus by carbon-silicon bonds can be made by
effecting reaction betwe~n halogenated polysilane of
formula (1~ and aromatic acylhalide of formula (2) in the
presence of an effective amount of a supported transition
metal complex having chemically combined groups of the
formula,
I R3 R4
h ~ ~S i R2 \ /~MX ( 4 )
5~ ~ 0 4-y
U~
where R2 is a divalent C(2-14) organic radical~ Q is a
nitrogen or phosphorous radical, R3 and R4 are monovalent
C(1-14) alkyl or aryl radicals, M is a transition metal
: selected ~rom palladium, platinum, rhodium or nickel, X is
previously defined, y is an integer equal to 1 to 3
inclusi~e and pre~erably 2. Surprisingly, the supported
transition metal complexes having chsmically combined
groups of formula (4), which are preferably ~ilicon
supported, have been found to ~e recyclable and regenerable
at the termination of the reaction.
~RIEF DESCRIPTION OF THE DRAWTNG
FIGURE 1 compares the reaction mixtures
catalyzed by the "Rich" silica~supported palladium catalyst
and the "commeriçal" carbon-supported palladium catalyst.
STATEME~T OF~ T~E INVENTIQN
There is provided by the present invention, a
method for making silylated aromatic organic materials
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1 3~704~
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having at least one nuclear-bound silicon atom attached to
an aromatic organic group by a carbon-silicon linkage
comprising,
(A) effecting reaction between a halogenated
polysilane of formula (1) and aromatic
acylhalide of formula (2) in the presence of an
effective amount of a supported transition
metal complex having chemically combined groups
of formula (4), and
(B) recovering silylated aromatic organic
material from the mixture of (A).
Some of the supported transition metal
complexes which can be used in the practice of the present
invention are shown by A.G. Allum et al., "Supported
Transition Metal Complexes II Silica as the Support",
Journal or Or~anometallic Chemistry 87 (1975~, pp. 203-216,
and M. Capka et al., Hydrosilylation Catalyzed by
Transition Metal Complexes Coordinately Bound to Inorganic
Supports" , Collection Czechoslov. Chem. Commun ., Vol . 39 ,
pp. 154 (1974). Additional supported transition metal
catalysts which can be used are shown by U.S. Patent
4~083~803/ Oswald et al., U.S. 3,487,112, U.S. 3,726,809
and U.S. 3,832,4040 There are includes for example, in
addition to silica, alumina and zeolites. The silica5 substrate can be in the form o~ silica extrudate.
Among the halogenated polysilanes which axe
included within formula (1) there are, ~or example,
chloropentamethyldisilane, 1,2-dichlorotetramethyldisilane,
1,1-dichlorotetramPthyldisilane, 1,1,2-trimethyltrichloro~
disilane, 1,1,2,2-tetrachlorodimethyldisilane,
hexachlorodisilane, 1,2-dibromotetramethyldisilane,
1,2-difluorotetramethyldisilane, 1,1,2,2,4,4,5,5,-octamethy
-1,2,4,5-tetrasilacyclohexasiloxane,
l-chlorononamethyltetrasil-3~oxane,
1,2-dichloro-1,2-diphenyldimethyldisilans, etc.
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Some of tha aromatic acyl halides which are
included within formula (2) are, for example,
monofunctional aromatic acyl halide such as benzoyl
chloride, trimellitic anhydride acid chloride,
chlorobenzoyl chloride, anisoyl
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chloride, nitrobenzoyl chloride, toluoyl chloride,
cyanobenzoyl chloride, bromobenzoyl chloride, dimethylamino-
benzoyl chloride, N-n-butyl trimellitic imide acid chloride,
etc.
Polyfunctional aromatic polyacyl halides which are
included within formula (2~ are, for example, terephthaloyl
chloride, phthaloyl chloride, isophthaloyl chloride, etc.
There are included among organic silanes which can
be made in accordance wi~h the practice of the method of the
present invention compounds suoh as phenyldimethylchloro-
silane, phenylmethyldichlorosilane, chlorophenyldimethyl-
chlorosilane, anisyldimethylchlorosilane, nitrophenyl-
dimethylchlorosilane, tolyldimethylchlorosilane,
cyanophenyldimethylchlorosilane, 4-dimethylchlorosilyl-
phthalic anhydride, N-n-butyl-4-dimethylchlorosilyl
phthalimide, bromophenyldimethylchlorosilane, etc.
Radical~ which are included within R of formula
~1) are, for example, C(l 8) alkyl radicals, for example
methyl, ethyl, propyl, butyl, pentyl, etc., chlorobutyl,
trifluoropropyl, cyanopropyl; aryl radicals, for example
phenyl, xylyl, tolyl, naphthyl, halogenated aryl radicals
such as chlorophenyl, dichlorophenyl, trichlorophenyl,
fluorophenyl, difluorophenyl, bromophenyl; nitro and
pslynitro aromatic radicals as well a~ arylether radicals,
for example, anisole, ethoxyphenyl, propoxyphenyl,
diphenylether, cyanophenyl, etc.
Some of the monovalent aromatir radicals and
substituted aromatic radicals which can be included within
Rl of formula (2) ar2, for example, phenyl, xylyl, tolyl,
naphthyl; halogenated aromatic radicals such as
chlorophenyl, dichlorophenyl, trichlorophenyl, etc.,
fluorophenyl, difluorophenyl, etc., bromophenyl,
dibrsmophenyl, etc.; nitro and polynitro axomatic radicals
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as well as aryl ether radicals for example, anisoyl,
ethoxyphenyl, propoxyphenyl, diphenylether. Additional
substituted aromatic radicals which can be included within
R1 are for example, cyanophenyl, polycyanophenyl, as well as
phthalimido radicals.
Typical of the chemically combined groups of
formula (4) are, for example, where R2 is selected from
ethylene, propylene, butylene, octylene, tetradecylene,
phenethyl, propylphenyl, butylphenyl and hexylphenyl; R3 and
R4 are selected from methyl, ethyl, propyl, butyl, and
isomers thereof, cyclopentyl, cyclohexyl, phenyl, tolyl,
xylyl, mesityl and anisyl; and X is selected from Cl, Br, I.
Further examples of the catalyst are,
\ /
CH2)
O PdC1
S -~}-Sl-tCH2) / r\
6 5 C6H5
\ /
~i~CH2~-- - - r
~PdC12 .
28 / \
CH3 C6H5
There are alss included among the aromatic
silylation reaction products silarylene halidest such as
1,4-~bis-chlorodimethylsilyl)benzene. The synthesis of such
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RD-17,758
silphenylene compounds can be made from terephthaloyl
chloride and 1,2~dichlorotetramethyldisilane.
An effective amount of silica-supported transition
metal catalyst is an amount of silica-supported transition
metal catalyst which is sufficient to provide from 0.005% by
weight to 20% by weight of transition metal based on the
weight of aromatic acyl halide.
In the practice of the present invention, reaction
is initiated between the halogenated polysilane of formula
(l) and the aromatic acylhalide of formula (2) in the
presence of an effective amount o the silica~supported
transition metal catalyst. Reaction can be carried out
under a variety of conditions. For example, the reactants
can be heated to the desired ~emperature in the absence of
solvent, while being stirred under an inert atmosphere or in
the presence of a nonreactive solvent with a boiling point
greater than about 100C to 300C. Nonreactive solvents
which can be used are, for example, o-xylene, anisole,
mesitylene, or nor~alogenated aromatic or aliphatic
solvents.
Depending upon the value of m in formula (2~ for
the aromatic acylhalide, and whether the halogenated
polysilane is a monofunctional or polyfunctional
halopolysilane, mslar proportions of the halogenated
polysilane and ~he aromatic acylhalide can vary widely.
There should be used sufficient halogenated polysilane to
prcvide at least 2 gram atoms of 5ilicon of the halogenated
polysilane, per mole of the aromatic acylhalide.
Temperatures which can be utilized in effecting
reaction between the halogenated polysilane and the aromatic
acylhalide are, for exampl~, 110C and preferably 135-145C
depending upon the nature of the reactants and conditions
- 1 3270~
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utilized, such as with or without organic solvent, as
previously discussed.
Organic silanes made in accordance with the
practice of the present invention can be hydrolyzed to a
variety of valuable intermediates, such as silarylenesilane
diols, bis(siloxaneanhydrides), bis(siloxaneimides), etc.
In order that those skilled in the art will be
better able to practice the present invention, the following
examples are qiven by way of illustration and not by way of
limitation. All parts are by weight.
EXAfflPLE 1
There was added 17.67 grams ~0.10 moles) of
palladium dichloride to a mixture of 75 grams (0.20 moles)
of diphenylphosphinoethyltriethoxysilane dissolved in 200 ml
of dry dichloroethane. The diphenylphosphinoethyltriethoxy-
silane was pr~pared in accordance with the method of A.G.
Allum et al., Journal Organomet.Chem. 87, 203 (1975). The
mixture of palladium dichloride and the triphenylphosphino-
ethyltriethoxysilane was heated to reflux until all of the
suspended palladium dichloride was consumed. The resulting
orange solution was alluted with 100 ml hexane. Upon
cooling there was ~ormed 89.9 grams ~97%) of bis(diphenyl-
phosphinoethyltriethoxysilyl)palladium dichloride as yellow
crystal
There was addad 585 grams of 1~8 in. diameter
~ilica extrudates to 60.7 grams of
bis(diphenylphosphinoethyltriethoxysilyl)palladium
dichloride di solved in 500 ml of methylene chloride. The
color of the resulting solution changed and the extrudates
were yellow orange. The catalyst was filtered and washed
with methylene chloride and air-dried at 125C for two
hours. Extrudates were then added to 700 ml of 5% aqueous
--e,--
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RD-17,758
HCl and allowed to stand for 12 hours followed by
filtration, washing with water and subse~ently acetone,
ether and pentane. The resulting catalyst was then
air-dried at 125C for eight hours. The catalyst was then
immersed in an excess of hexamethyldisilazane for two hours
at room temperature, followed by filtration, washing with
methylene chloride and pentane and drying under vacuum at
80C for 15 hours. There was obtained a silica-supported
palladium silylation catalyst having a plurality of
chemically combined groups of the formula,
C6H5 /C6H5
Si--CH2CH2 P~ ~Cl
~ ~ 0 / Pd
w ~ ----O--Si--CH2CH2 ~ P ~ ~Cl
6 5 C6H5
Chemical analysis showed that ~he catalyst contained 2.02%
by weiyht of palladium.
There was heated neat to 145C, a mixture of 562
gr~ms (2.67 moles) trimellitic anhydride acid chloride, 700
1~ grams (2.67 moles3 of 1,2-dichlorotetramethyldisilane and 40
grams (0.3 mole %) of the above silylatio~ catalyst having
2.02% by weight of palladium. Rapid outqassing of carbon
monoxide occurred from the catalyst surface and
dimethyldichlorosilane formed during reaction was
continuously removed by distillation. After heating the
mixture for 12 hours at 145C, gas chromatography indicated
complete reaction of the trimellitic anhydride acid
chloride. The resulting mixture was then decanted. Vacuum
distillation resulted in ~he production of 169 grams (73%
1 32704~
RD-17,75B
yield) of 4-chlorodimethylsilylphthalic anhydride as a clear
liquid, b.P. 141C/0.1 torr.
EXAMPLE 2
The procedure of Example 1 was repeated for making
the silica-supported palladium catalyst except that there
was used 89.9 grams (0.16 mole) of bis(diphenylphosphino~
ethyl)triethoxysilane and 1,064 grams of 200-300 mesh
silica. Based on method of preparation and chemical
analysis, there was obtained a silica-supported palladium
catalyst having about 1% by weight of palladium.
A reaction mixture containing 203 grams (1.0 mole)
of terephthaloylchloride and 187 grams (1.0 mole) of
1,2-dichlorotetramethyldisilane was stirred and heated neat
to 245C until a homogeneous mixture was obtained. There
was added to the mixture, 32 grams of the silica-suppor~ed
1% palladium catalyst. Rapid evolution of carbon monoxide
gas occurred and dimethyldichlorosilane was remov~d
continuously as it formed. After 12 hours at 145C NMR
analysis showed complete reaction of the terephthaloyl-
~hloride. The reaction mixture was cooled to roomtemperature and filtered under nitrogen to remove the
catalyst. Distillation of th~ mixture provided 174 grams
(75%~ yield of 4~chlorodimethylsilylbenzoylchloride as a
clear liquid, boiling point 97C/0.1 torr.
EXAMPLE 3
The procedure of Example 2 was repeated utilizing
10 grams (4.93 x 10 2 moles3 of terephthaloylchloride, 9.~
grams (4.93 x 10 2 moles) of 1,2-dichlorotetramethyldisilane
and 3 grams of the 1% palladium (II) on silica ~rom Example
2. The mixture was heated to 145C neat. There was also
utilized in the mixture, an unreactive GC internal standard,
--10 -
1 327044
RD-17,~58
tetradecane (3.16 grams, l.~3 x 10 2 moles). After three
hours, the reaction was stopped and the progress of the
reaction was monitored by gas chromatography. The same
procedure was repeated except that in place of the 3 grams
of reused silica-supported 1% palladium prepared in Example
2, there was used 3 grams of a 1% commercially available
palladium on carbon, Johnson-Mathey Corporation TS2276. An
additional reaction was also run employing 3 grams of a
commercially-available silica-supported 1% palladium
catalyst from Engelhardt Company. It was determined that
the latter- commercially available silica-supported palladium
catalyst had the palladium absorbed onto the surface of the
silica instead of being chemically combined, as shown in
Examples 1 and 2.
lS The various mixtures were heated continuously for
3 hours under neat conditions and the progress of the
respective reactions was monitored by gas chromatography.
The catalysts were then filtered, washed with methylene
chloride, dried under nitrogen and reintroduced into fr sh
aiiquots of the respective reaction mixtures. It was found
that the reaction mixture containing the commercially
available silica-supported palladium catalyst which was
absorbed onto the surface of the silica, could not be
satisfactorily monitored, as little or no reaction had
2S occurred. However, the re~ults of five runs were monitored,
as shown in the drawing, comparing the reaction mixture
catalyzed by the silica-support~d palladium catalyst having
palladium chemically combined to silica through connecting
groups of formula (4~ Xich" and the reaction mixture
containing the "Gommercial" palladium catalyst using carbon
as a support. After three runs, the respective catalysts
ware removed from the mixtures, slurried in carbon
tetrachloride, and gaseous chlorine was introduced. The
~ 3 2 1 0 '~ ~ ~D-17,758
Rich catalyst of the present invention turned yellow-orange
in color and the rate of color change could be increased by
mildly heating the carbon tetrachloride following filtration
and washing with methylenechloride. After the catalysts
were dry, they were reintroduced in fresh aliguots of
starting materials. It was found that the "reactivated"
catalyst of the present invention "Rich" showed 85% of its
initial activity from the first run, while no change was
noted in the commercially available catalyst.
EXAMPLE 4
After several runs, the silica-supported catalyst
of Example 1, a batch of 2% palladium on 1/8" silica
extrudates, had been completely reduced to palladium black
and was no longer active in the silylation process. The
spent silica-supported palladium catalyst was then slurred
in a 5% aqueous solution of copper chloride for 10 minutes
and oxygen wa~ then bubbled through the mixture. An
exothermic reaction occurred and the silica-supported
palladium catalyst turned from black to yellow-oran~e in
color. The mixture was then filtered and the
silica-supported palladium catalyst was then analyzed.
Elemental analysis showed that the spent catalyst had 1.3%
palladium while the original wa~ 2.02% palladium. After the
spent catalyst was reoxidized, the reactivated catalyst
contained 0.7% pall~dium and 1% copper.
A reaction mixture containing 4.93 x 10 2 moles of
trimellitic anhydride acid chloride and 4.93 x 10 3 moles o
1,2-dichlorotetramethyldisilane was heated to 145~ in the
presence of 3 grams of the above-described silica-supported
reactivated catalyst. After 3 hours at 145C, ~9
chromatography indicated complete reaction of the
trimellitic anhydride acid chloride. The resulting mixture
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was then decanted and vacuum distilled to provide 7.23 grams
or a 61% yield of 4-chlorodimethylsilylphthalic a~lydride.
EXAMPLE 5
The procedure o Example 2 was repeated for makin~
the 1% by weight of palladium catalyst.
A reaction mixture containing 3 gram (2.13 x 10 2
mole) of benzoyl chloride and 4.85 grams (2.13 mole3 or
sym-tetrachlorodimethyl disilane was ~tirred and heated to
130-135~C neat until a homogeneous mixture was formed.
There was added to the mixture 2.2 g of 1% palladium on
200-300 mesh silica. Rapid evolution of carbon monoxide
occurred and trichloromethylsilane was removed continuously
as it formed. After 15 hours at 130C, NMR analysis showed
complete reaction of benzoyl chloride.
The above reaction was repeated with other
substrates, as shown by the followin~ equation and Table,
where Ar is phenyl, or substituted phenyl:
R ( C133) Si(CH3)C12 '
+ C~3SiC13 + C0
-13-
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RD~7,7S8
TABLE
Substrate Mole % Mole %
where R = ArSiCH3C12 ArCl
.~
H 90 10
P-Cl 8g 11
P-COCl 8~ 1~
3,4 N-CH3 36 7
o
o
3,4 ~ O 95 5
~ C
o
The above results show that the silica supported
catalyst of the present invention having chemically combined
groups of formula (4~, has superior selectivity when used to
make polyfunctional aryl silanes from aryl substrates
substituted with a variety of activating groups employin~
polysilanes having silicon atoms wi~h at least two halogen
radicals per silicon.
In contrast, a similar silylation reaction was
conducted with the same substrates using the 1% commercially
1 32704~ RD-17,75~
available palladium on carbon catalyst of Example 3. It was
found that a wide variation resulted in selectivity in
accordance with the substituent R on the phenyl ring. For
example, when R was hydrogen, only a trace of the desired
phenyl silane was obtained while a 78% yield was obtained
with chloroacylphthalicanhydride. A 67% yield was obtained
with terephthaloyl chloride.
Although the bove examples are directed to only a
few of the very many variables which can be utilized in the
practice of the method of the present invention, it should
be understood that the present invention is directed to a
much broader variety of silica-supported palladium catalyst,
halogenated polysilane and aromatic acylhalide shown in the
description precesding these examples.
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