Polycarbosilanes and process for preparing them
AssigneeKali-Chemie Aktiengesellschaft
InventorsPeter Sartori, Wolfgang Habel, Heinz-Peter Judenau
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Abstract
Polycarbosilanes having Si units which are linked by phenyl-substituted methylene bridges or by partially or completely fluorinated hydrocarbon bridges. These polycarbosilanes are obtained by a Grignard polycondensation reaction. If phenyl substituents are present on the silicon atoms of the polycarbosilanes, they may also optionally be exchanged for halogen atoms in additional halogenating reactions, so that polycarbosilanes can be prepared which are both fluorinated on the hydrocarbon bridges and halogenated (particularly fluorinated) on the silicon atoms.
Claims18
A polycarbosilane composed of structural units corresponding to the formula I:
- ##STR8## wherein R.sup.1 represents hydrogen, alkyl, cycloalkyl, aryl, arylalkyl or halogen, whereby R.sup.1 may have different meanings in various units of one and the same polycarbosilane;
- R.sup.2 represents alkyl, cycloalkyl, aryl, arylalkyl, or halogen, whereby R.sup.2 may have different meanings in various units of one and the same polycarbosilane;
- R.sup.3 represents fluorine or phenyl, whereby R.sup.3 may have different meanings in various units of one and the same polycarbosilane;
- R.sup.4 represents hydrogen, fluorine, or phenyl, whereby R.sup.4 may have different meanings in various units of one and the same polycarbosilane,
- n represents the numeral 1 if R.sup.3 and/or R.sup.4 represents phenyl, and n represents an integer from 1 to 6 if R.sup.3 represents fluorine and R.sup.4 represents hydrogen or fluorine, whereby n may have different meanings in various units of one and the same polycarbosilane, and
- p represents an integer from n to 2n-1, whereby p may have different meanings in various units of one and the same polycarbosilane.
A process for preparing a polycarbosilane composed of structural units corresponding to the formula I:
- ##STR10## in which R.sup.1 represents hydrogen, alkyl, cycloalkyl, aryl, arylalkyl or halogen, whereby R.sup.1 can have different meanings in various units of one and the same polycarbosilane;
- R.sup.2 represents alkyl, cycloalkyl, aryl, arylalkyl or halogen, whereby R.sup.2 can have different meanings in various units of one and the same polycarbosilane;
- R.sup.3 represents fluorine or phenyl, whereby R.sup.3 can have different meanings in various units of one and the same polycarbosilane;
- R.sup.4 represents hydrogen, fluorine or phenyl, whereby R.sup.4 can have different meanings in various units of one and the same polycarbosilane,
- n represents the numeral 1 if R.sup.3 and/or R.sup.4 represent phenyl, and n represents an integer from 1 to 6 if R.sup.3 represents fluorine and R.sup.4 represents hydrogen or fluorine, whereby n can have different meanings in various units of one and the same polycarbosilane, and
- p represents an integer from n to 2n-1, whereby p can have different meanings in various units of one and the same polycarbosilane;
- wherein
- for preparing a polycarbosilane composed of structural units corresponding to the formula Ia:
- ##STR11## in which R.sup.1a represents hydrogen, alkyl, cycloalkyl, aryl or arylalkyl, whereby R.sup.1a can have the same or different meanings in various units of one and the same polycarbosilane,
- R.sup.2a represents alkyl, cycloalkyl, aryl or arylalkyl, whereby R.sup.2a can have the same or different meanings in various units of one and the same polycarbosilane,
- R.sup.3, R.sup.4, n and p have the meanings given above;
- said process comprises the steps of:
- reacting a dihalosilane corresponding to the formula IV ##STR12## with a dibromide compound corresponding to the formula V
- Br--(C.sub.n R.sub.p.sup.3 R.sub.2n-p.sup.4)--Br (V)
- wherein
- X represents the halogens chlorine, bromine or iodine, and
- R.sup.1a, R.sup.2a, R.sup.3, R.sup.4, n and p have the meanings given above, in a Grignard polycondensation reaction with magnesium metal.
Dependencies are inferred from the claim text.