Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Patent
1998-01-08
1999-09-07
Shaver, Paul F.
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
252573, C07F 708
Patent
active
059489294
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to fluorosilicon compounds and to a preparation method.
2. Description of the Prior Art
The majority of known fluorinated organosilicon compounds have structures in which a fluorine-containing groups such as perfluoroalkyl is bonded to a silicon atom through a dimethylene or trimethylene group. Synthesis of these compounds usually requires many stages, including a Grignard reaction and a reaction involving a precious metal catalyst, such as platinum (cf. U.S. Pat. No. 5,202,453; EP 0,538,061 A2). Reactions for making fluorinated organosilicon compounds by way of a cyclization process between olefine derivatives of silicone and fluorine have also been described (cf. U.S. Pat. No. 2,596,967; UKP 760,201 and 802,358; Holbrook G. W. J. Am.Chem.Soc 82 825 (1960); Park J. D. J. Org.Chem., 25, 1628 (1960). However, this reaction has been largely ignored over the past ten years.
SUMMARY OF THE INVENTION
According to the first aspect of the invention there is provided a fluorinated organosilicon compound represented by the formula: ##STR2## Preferably the compound is represented by the following formula: ##STR3## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently selected from alkyl groups having 1-4 carbon atoms or independently selected from the above alkyl groups,the CF.sub.3 CH.sub.2 CH.sub.2 -- group, and the R.sup.6 (R.sup.5).sub.c (CF.sub.2 CF.sub.2 O).sub.b CFCF.sub.2 CH.sub.2 CH -- group, where R.sup.6, R.sup.5, a,b and c are as hereinafter defined. R.sup.5 is a bivalent group such as --OCF.sub.2 --, --OCF.sub.2 CF.sub.2,-- or --OCF.sub.2 CF(CF.sub.3)--. R.sup.6 is a --OCF.sub.3 -- group or --F atom. a is an integer from 0 to 6, b is zero or 1, c is an integer between 2 and 6.
Fluorinated organosilicon compounds in accordance with the invention have a wide operating temperature range and excellent chemical resistance; they are oil- and water- repellent and have outstanding dielectric properties. In addition, due to the phenomenon of "super-flexibility", the viscosity of these materials is much lower than their molecular weight would suggest. All these properties, together with their density, which can be arranged to be in the range 1.3-1.7 g/ml make these liquids very suitable for use as base liquids in Electro-Rheological (ER) Fluids as well as more general applications.
The invention includes a cyclo butane ring of formula: ##STR4##
A preferrred formula being: ##STR5##
According to a second aspect of the invention, there is provided a method of manufacturing a compound in accordance with the first aspect by reacting a vinyl siloxane of general formula: ##STR6## wherein R.sup.1, R.sup.2, R.sup.3,and R.sup.4 have the meanings defined above, with a perfluoro-olefin of the general formula: present of a free radical inhibitor.
The compounds are produced by a reaction between vinyl siloxane and perfluoro-olefin in the presence of a free radical inhibitor at elevated temperature and pressure.
Preferably, in the cyclization reaction of the vinylsiloxane and the perfluoro-olefin, the ratio of reactants is in the range 1-2 moles of perfluoro-olefin for each mole of vinyl siloxane, preferably between 1.1 and 1.6. The reaction temperature may be in the range 150-250.degree. C. and preferably between 180 and 230.degree. C. The reaction time may be 5-100 hours, and typically between 10 and 70 hours. The reaction is preferably carried out at elevated pressure in an autoclave.
Typical examples of fluorinated organosilicon compounds prepared by this method include: ##STR7##
1. Fluorinated organosilcon compounds having at least one cyclobutane ring connected with fluoro contained groups through oxygen atom, the compounds being represented by the formula wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently selected from alkyl groups having 1-4 carbon atoms, the CF.sub.3 CH.sub.2 CH.sub.2 -- group, the CH.sub.2 .dbd.CH-- and the ##STR8## R.sup.5 is a bivalent group selected from --OCF.sub.2 --, --OCF.sub.2 CF.sub.2 --,
REFERENCES:
patent: 2596967 (1952-05-01), Frost
patent: 4996344 (1991-02-01), Inomata et al.
patent: 5262557 (1993-11-01), Kishita et al.
"Reactions of Vinylsilanes With Tetrafluoroethylene", Zhurnal Obshchei Khimii, vol. 54, No. 10, 1984, pp. 2302-2306.
FSO Limited
Shaver Paul F.
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