Process for preparing fluoroalkyl-containing organosilicon...

Details Process for preparing fluoroalkyl-containing organosilicon... Process for preparing fluoroalkyl-containing organosilicon...

1998-12-09

2001-07-03

Shaver, Paul F. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Silicon containing

C556S450000, C556S454000, C556S457000, C556S458000, C556S465000, C556S485000, C528S015000

Reexamination Certificate

active

06255516

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to processes for preparing fluoroalkyl organosilicon compounds by reacting fluorine-containing olefins with organosilicon compounds in the presence of a platinum catalyst.
2. Discussion of the Background
In recent years, a large number of new applications have been discovered for fluoroalkylchlorosilanes and fluoroalkylalkoxysilanes. These compounds are useful as surfactants to modify the surfaces of lenses and optical fibers or for producing oil-, dirt-, and water-repellent surfaces, as lubricants, as primers for fluoro resins, as ingredients in cosmetic preparations, and as modifiers in fluoro-rubbers and silicone rubbers.
Platinum catalysts are often used for hydrosilylation reactions of fluoroolefins to produce the above-mentioned silanes. Typically, the preferred catalysts are those in which platinum is in the (+4) oxidation state. However, these Pt(IV) catalyst systems suffer from a number of disadvantages.
In many cases, the reactions are required to run under a closed system. JP 02 178 292 A2 discloses the reaction of F
3
C(CF
2
)
2
C(CF
3
)
2
CH
2
CHCH
2
with HSiCl
3
in a blown glass tube in the presence of a H
2
PtCl
6
catalyst at a temperature of 100° C. for 3 h with a yield of 83%. EP 0 538 061 A2 discloses a reaction of CF
3
CF
2
CF
2
OCF(CF
3
)CF
2
OCF
2
CF
2
CHCH
2
with CH
3
SiHCl
2
in the presence of H
2
PtCl
6
in a steel autoclave at a reaction temperature of 120° C., with a reaction period of 20 h and a resulting yield of 67%.
At atmospheric pressure, such reactions are relatively lengthy. For instance, JP 06 239 872 A2 discloses a reaction time of 48 h for the reaction of C
3
F
7
O[CF(CF
3
)CF
2
O]
3
CF(CF
3
)CHCH
2
with (CH
3
)
3-n
SiHCl
n
(n=1,2) in the presence of H
2
PtCl
6
at a reaction temperature of 150° C., resulting in a yield of 88%. WO 94/20442 discloses a yield of 89% and a reaction period of 50 h for a hydrosilylation reaction, at a reaction temperature of 100° C. in the presence of H
2
PtCl
6
.
The reactions may not be stereospecific. WO 94/20442 additionally discloses that, for example, in the hydrosilylation reaction of p-CF
3
C
6
H
4
CHCH
2
with CH
3
SiHCl
2
, isomerization may occur with a concomitant reduction in selectivity. In this case, an 87:13 ratio of &bgr;-silylated to &agr;-silylated fluoroolefin is obtained with a yield of 89%.
To raise the selectivity and reactivity, and in some cases to improve the solubility of the platinum compound, complexing reagents are added to the platinum catalyst. For example, JP 03 106 889 A2 teaches the addition of acetone. EP 0 466 958 A1 discloses isopropanol as an additive, while EP 0 573 282 A1 discloses the use of H
2
PtCl
6
in 2-ethylhexanal. It is also known to add m-xylene hexafluoride to the Pt catalyst (EP 0 573 282 A1). However, in all of these examples, the cost and complexity of preparation are considerable.
In general none of the above-mentioned catalyst systems are sufficiently reactive or selective, with the result that, from an economic standpoint, such processes are of little interest for the preparation of fluoroalkyl-containing organosilicon compounds.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a process for preparing fluoroalkyl organosilicon compounds simply and economically.
Another object of the present invention is to provide a process for preparing fluoroalkyl organosilicon compounds under mild reaction conditions with high yields and high selectivity.
Another object of the present invention is to provide a process for preparing fluoroalkyl organosilicon compounds using KARSTEDT catalysts.
Another object of the present invention is to provide a process which proceeds uniformly under atmospheric pressure and at low temperatures.
Another object of the present invention is to provide a process which does not require an excess amount of organosilicon reactant, thereby minimizing the proportion of byproducts that require separation and disposal.
Another object of the present invention is to provide a process for preparing fluoroalkyl organosilicon compounds in which unwanted isomerization is reduced or eliminated.
Another object of the present invention is to provide a process for preparing fluoroalkylalkoxy organosilicon compounds.
Another object of the present invention provides for surface-treating agents for enhancing the surface of plastics, glass, metals, ceramics and stone; textile auxiliaries; and architectural preservative preparations which contain fluoroalkyl organosilicon compounds produced by the process.
These and other objects of the present invention have been achieved by reacting, in the presence of a Pt(0) complex catalyst, at least one fluoroolefin with at least one organosilicon compound that contains at least one H-Si group.
The first embodiment of the invention relates to a process for preparing fluoroalkyl organosilicon compounds, which includes:
reacting, in the presence of a Pt(0) complex catalyst,
at least one fluoroolefin with
at least one organosilicon compound that contains at least one H-Si group.
The second embodiment of the invention relates to a process for preparing a fluoroalkylalkoxy organosilicon compound, which includes:
reacting, in the presence of a Pt(0) complex catalyst,
at least one fluoroolefin with
at least one organosilicon compound that contains at least one H-Si group; and
esterifying with an alcohol.
The third embodiment of the invention relates to a fluoroalkyl organosilicon compound prepared by a process which includes:
reacting, in the presence of a Pt(0) complex catalyst,
at least one fluoroolefin with
at least one organosilicon compound that contains at least one H-Si group.
By means of the present invention, fluoroalkyl and fluoroalkylalkyoxy organosilicon compounds can be produced with yields of up to 99%. Heretofore, it was completely unexpected that a process of reacting at least one fluoroolefin with at least one organosilicon compound that contains at least one H-Si group, in the presence of a Pt(0) complex catalyst, would proceed so uniformly, under such mild conditions, and with such improved reactivity, selectivity, and yield.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Other features of the invention will become apparent in the course of the following descriptions of exemplary embodiments which are given for illustration of the invention and are not intended to be limiting thereof.
In the present process, it is preferred to employ a Pt(0) complex catalyst of the KARSTEDT type. More preferably, the KARSTEDT catalyst is selected from the group consisting of bis[1,3-bis(eta-2-ethenyl)-1,1,3,3-tetramethyldisiloxane]platinum(0), triphenylphosphine-[1,3-bis(eta-2-ethenyl)-1,1,3,3-tetramethyldisiloxane]platinum(0) and 2,4,6,8-tetraethenyl-2,4,6,8-tetramethylcyclotetrasiloxane platinum(0). Preferred KARSTEDT catalysts are those which contain 0.01-20% by weight of platinum, based on the weight of the catalyst, preferably 0.1-10% by weight of platinum and, more preferably 0.5-5% by weight of platinum. These ranges include all specific values and subranges therebetween. The catalyst system can be dissolved in an inert solvent. Suitable solvents are xylene (o-, m-, and p-) and toluene. Other inert solvents may be used that are known in the art having boiling points between 100-200° C., preferably 110-160° C., and more preferably 110-145° C. These ranges include all specific values and subranges therebetween.
DE-A 1 941 411, FR-A 2 474 890 and U.S. 3,775,452 disclose platinum catalysts of the KARSTEDT type, the contents of each are hereby incorporated by reference.
The present reaction is preferably carried out employing at least one fluoroolefin of the general formula (I)
R
1
YCH=CH
2
  (I)
in which
R
1
is a mono-, oligo-, or perfluorinated alkyl group having 1 to 20, preferably 1 to 9 carbon atoms or a mono-, oligo-, or perfluorinated aryl group having 6 to 10, preferably 6 carbon atoms and Y is a —CH
2
—, —O— or —S— group. Examples are —CF
3
(CF
2
)
n
CH

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