Silicon monomers dichlorosilane

Methyl(chloromethyl)dichlorosilane is used to obtain silicone liquids, elastomers and polymers for varnishes, as well as monomers with various carbofunctional groups at the silicon atom. 

The R1 values obtained for such phenylethynyl substituted siloxanes are higher then that reported for traditional aromatic-based systems [9] or the phenol modified ones (1.50-1.53) [10]. The synthesis of high refractive index (methyl)(diphenyle thenyl)-dichlorosilane via hydrosilylation was also described [1]. Such monomer was later hydrolyzed and condensed into silicone fluid. Similar process was also presented, applying silylative coupling process in the synthesis of an analogous (methyl)(phenylethenyl)diethoxysilane [11], so the two reactions shall be discussed in the following section. 

Hydrosilylation is by far the most important ronte for obtaining monomers and other precursors to fluorinated polysiloxanes. Hydrosylilation [104] is the addition of silicon hydride moiety across an unsatnrated linkage nsing transition metal complexes of platinum or rhodium such as Speier s catalyst, hexachloroplatinic acid in isopropanol [103], The preparation of methyl(3,3,3-triflnoropropyl)dichlorosilane, which is the precnrsor of the indnstrially most important PMTFPS, is described in patent literatnre [105],... 

Almost simultaneously to Cao et al.. Holmes et al. described the preparation of the 3,6-disubstituted dibenzosilole monomers 4, 5, and 10 by two alternative routes (Scheme 18) [211]. The first method employs selective transmetalation of 2,2 -diiodo-5,5 -dibromobiphenyl (3) followed by silacycUzation (as used for the corresponding 2,7-dibenzosilole) [206], while the second exploits the displacement of methyl groups from a dibenzosilole 8. The latter route demonstrates the versatility of the alkyl-displacement on silicon reaction to introduce solubilising substituents to the bridging silicon, keeping in mind the limited couunercial availability of dis-ubstituted dichlorosilanes. 

This application has been developed by the Dow Corning Corporation, a large manufacturer of silicone materials, and was first reported in 1996 [30], Dow Coming produces its own chlorosilane intermediate feedstocks chlorosilane monomers can then be reacted in variety of way to produce different silicone polymers. One of the more important reaction involves the hydrolysis of dimethyl-dichlorosilane (Me2SiCl2) to polydimethylsiloxane [—Si(Me2)0—]. 

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