Preparation using chlorosilane

Aryl ketones. Aromatic aldehydes are converted to ketones by condensation with benzotriazole in the presence of triethyl orthoformate, alkylation of the resulting ethers [ArCH(OEt)Bt], and treatment with dilute HCl to expel benzotriazole and ethanol. Silyl ketones are similarly prepared, using chlorosilanes as alkylating agents. ... 

Nevertheless Kipping made a number of contributions of value to the modem silicone industry. In 1904 he introduced the use of Grignard reagents for the preparation of chlorosilanes and later discovered the principle of the inter-molecular condensation of the silane diols, the basis of current polymerisation practice. The term silicone was also given by Kipping to the hydrolysis products of the disubstituted silicon chlorides because he at one time considered them as being analogous to the ketones. 

Phenyl and vinyl modified versions of poly(m-carborane-siloxane) were readily prepared using the procedure just described, by introducing the appropriate silane feed into the reaction mix.19 Typically, 1 to 3 mol % di-chloro-methylvinylsilane was added to the di-chlorosilane feed in the syntheses described earlier. The repeat unit of the phenyl modified poly(w-carborane-siloxane) is shown in 5. 

Gaul and co-workers [15] prepared a variety of polysilazanes by using chlorosilanes and hexa-methyldisilazane to control polymer molecular weight, rheology, and spinnability (Eq. 9). 

The preparation of organofunctional silica gels on industrial scale is performed by liquid phase reaction. As a solvent, water, a water/ethanol or water/acetone mixture is used. Chlorosilanes or alkoxysilanes are used for this type of modification. 

Polymerization of terpenes using acidic catalysts such as AICI3 and BF3 is another major reaction for terpenes. B-Pinene and dipentene yield almost quantitative amounts of polymer in the 600-2000 MW range, while a-pinene yields only about 60% polymer in this range (32). More recently, it was claimed that an all a-pinene resin can be prepared by using chlorosilane as a catalyst (33). Monoterpenes condense with phenol in the presence of BF3 to form terpene-phenolic resins. 

On the other hand, the (AB) star copolymers were prepared by the condensation of AB diblock anions using chlorosilane compound [59]. This star copolymer could also be synthesized by crosslinking diblock monocarbanionic [60,61] or monocarbocationic chains [62,63] with bis-unsaturated monomers. 

Silcones are important products of silicon. They may be prepared by hydrolyzing a silicon organic chloride, such as dimethyl silicon chloride. Hydrolysis and condensation of various substituted chlorosilanes can be used to produce a very great number of polymeric products, or silicones, ranging from liquids to hard, glasslike solids with many useful properties. 

Apart from the direct action of an alcohol on a chlorosilane or siUcon, the only other commercial method used to prepare alkoxysilanes is transesterification. 

On the commercial scale silicone resins are prepared batchwise by hydrolysis of a blend of chlorosilanes. In order that the final product shall be cross-linked, a quantity of trichlorosilanes must be incorporated into the blend. A measure of the functionality of the blend is given by the R/Si ratio (see Section 29.3). Whereas a linear polymer will have an R/Si ratio of just over 2 1, the ratio when using trichlorosilane alone will be 1 1. Since these latter materials are brittle, ratios in the range 1.2 to 1.6 1 are used in commercial practice. Since chlorophenylsilanes are also often used, the CH3/CgH5 ratio is a further convenient parameter of use in classifying the resins. 

Thienyllithium has been used for the preparation of triphenyl-2-thienylsilane, 2-thienylsulfinic acid, and di-2-thienylketone by means of reactions with triphenyl chlorosilane, sulfur dioxide, and... 

Tetramethyl-l,3-disilacyclobutane had been prepared earlier by Knoth and Lindsey [10], but a multistep synthesis was involved which was not generalizable to the synthesis of Si-functional 1,3-disilacyclobutanes. The reaction shown in eq. 4, provided it is carried out in the right way, represents a good, general route to 1,3-disilacyclobutanes. This reaction was reported first by Muller and his coworkers [11]. In this work, diethyl ether was used as reaction solvent and the product yield was only around 4%. Somewhat better yields were obtained" by Russian workers [12], but it was the detailed studies of the (chloromethyl)chlorosilane/ magnesium reaction by Kriner [13] which provided a good synthesis of... 

In the past five years, researchers at Dow Corning have made a concentrated effort to explore and develop the use of Si-Cl/Si-N redistribution reactions as a means of preparing tractable, polysila-zane precursors to SijN (3A-A2). Initial work focussed on the reaction of chlorosilanes and chlorodisilanes with hexamethyl-disilazane ... 

The transmetalation of trimethylsilylphosphanes with germanium and tin halides is a useful way to prepare compounds with P—Ge and P—Sn bonds by simple chlorosilane elimination. The reverse reaction, i. e. formation of P—Si bonds by chlorosilane cleavage of germyl- and stannylphosphanes has not yet been reported. Recently, we observed that hexachlorodisilane "transsilylates di-r-butyl(trimethyl-silyl)phosphane 1 much faster than tetrachlorosilane to give trichlorosilylphosphane 2 ... 

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