Chlorosilanes trimethylchlorosilane

The first rectification stage. From collector 10 the mixture of methyl-chlorosilanes is periodically fed into pressure container 11, from where at 50-65 °C it is sent through heater 12 (by self-flow) onto the feeding plate of rectification tower 13. From the tower the tank liquid (methyltrichloro-silane, dimethyldichlorosilane and tank residue) flows into tank 14, where the temperature of 80-90 °C is maintained, and from there is continously poured into collector 22. After the tower, vapours of the head fraction at a temperature below 58 °C, consisting of the rest of methylchloride, di- and trichlorosilane, dimethylchlorosilane, methyldichlorosilane and the azeotropic mixture of silicon tetrachloride and trimethylchlorosilane are sent into refluxer 15, cooled with water, and into refluxer 16, cooled with salt solution (-15 °C). After that, through cooler 17 the condensate is gathered in receptacle 19. Volatile products, which did not condense in reflux-ers 15 and 16, are sent into condenser 18 cooled with Freon (-50 °C). There they condense and also flow into receptacle 19. As soon as it is accumulated, the condensate is sent from receptacle 19 into collector 20. 

Industrial chlorination of methyltrichlorosilane and trimethylchlorosi-lane is conducted by a similar technique. It should be borne in mind, however, that the chlorination speed of methyl groups greatly depends on the number of methyl radicals in the original methylchlorosilanes. Trimethyl-chlorosilane is the easiest to chlorinate, methyltrichlorosilane is the hardest. For example, the chlorination speed at the transition from dimethyldi-chlorosilane to trimethylchlorosilane increases 9-fold. 

The hydrolytic cocondensation of trimethylchlorosilane, dimethyldi-chlorosilane and isobutylmethyldichlorosilane with subsequent partial polycondensation of the products can be used to obtain oligomers with methyl and isobutyl groups at the Si atom ... 

The strategy of incorporating silicon as a reactive component in the polymeric system to attain flame retardancy has been explored. For example, Ebdon et al. carried out silylation to the polystyrene using //-butyl lithium in the presence of tetramethylethylenediamine, followed by reaction with trimethylchlorosilane, dichlorodimethylsilane, or trichloromethylsilane, as shown in Scheme 8.1. Poly(vinyl alcohol) films have also been modified with chlorosilanes (Scheme 8.1). 

The described metallo-silanols exhibit high stability concerning condensation, however, the OH groups display reasonable reactivity in context with chlorosilanes. These properties can be used to transform the ferrio-silanols 4a, 4b via reaction with trimethylchlorosilane to the ferrio-di- and -trisiloxanes 13a, 13b characterized by a hydrogen substituted a-silicon. In the case of 4b the first siloxane unit is established after one day, the second takes five days (13b). The same reaction pattern can be applied for the generation of the ruthenio-disiloxanes 13c, 13d, resulting fi-om the treatment of the ruthenio-silanols 8c, 8e with Me2Si(R )Cl. 

Wurtz coupling reactions of chlorosilanes are the main route to the silicon-silicon bonded compounds. For example, hexamethyldisilane can be prepared by refluxing trimethylchlorosilane with lithium sand in THF (97%). Lithium may be substituted by sodium by using a mixture of HMPA-THF as the solvent. Linear and branched oligosilanes can be prepared by the same method (equations 55-57). 

TRIMETHYLCHLOROMETHANE see BQROOO TRIMETHYL CHLOROSILANE see TLN250 TRIMETHYLCHLOROSILANE pop seeTLN250 TRIMETHYLCHLOROSTANNANE see CLTOOO TRIMETHYLCHLOROTIN see CLTOOO... 

One approach to solving the problem of residual silanol interactions has involved improvements in the synthetic procedures for the production of hydrocarbonaceous stationary phases. One synthetic approach for the elimination of residual silanol groups involves the reaction of the bonded phase with a small silylating reagent such as trimethylchlorosilane which is presumed to have easier access to silanol groups than bulkier, long-chained chlorosilanes. An alternative, synthetic approach involves surface polymerization of the stationary phase, which is believed to reduce the accessibility of surface silanol groups to polar analytes in the mobile phase. Stationary phases produced by the former method are often referred to as end-capped and stationary phases produced by the latter method are sometimes called base-deactivated. ... 

Mesoporous silicas with various pore sizes are hydrophobic by silylation with silanes. Changes in the pore structure as a result of the silylation reactions are monitored in order to assess the distribution of the hydrophobic groups. Extensive polymerization of dimethyldi-chlorosilane causes blocking of the micropore fraction. For silica with pore sizes in the supermicroporous range (2nm), this leads to hydrophobization of almost exclusively the outer surface. While for trimethylchlorosilane a smaller number of molecules react with the surface, modification is more homogeneous and an open structure is optimally preserved. Both silanes lead to lower surface polarity and increased hydrothermal stability, i.e., preservation of the porous structure during exposure to water.12231... 

Hexamethyldisilazane has been prepared by Sauer and Hasek6,7 from the reaction of ammonia with trimethyl-chlorosilane in an inert solvent. When the reaction was carried out in liquid ammonia, a somewhat smaller yield of hexamethyldisilazane was obtained, along with appreciable amounts of trimethylsilanol and hexamethyldisil-oxane6 owing to hydrolysis during recovery of the product. Presumably other trimethylhalosilanes could be employed in place of trimethylchlorosilane, but the ready availability of the latter favors its use. 

An apparatus has been developed392 for the analysis of a mixture containing tri-chlorosilane, methyldichlorosilane, silicon tetrachloride, trimethylchlorosilane, di-methyldichlorosilane and methyltrichlorosilane by gas-liquid chromatography on a column of nitrobenzene supported on Celite 545. The column is eluted with nitrogen and the emergent gas is absorbed in flowing 0.01 N potassium ohloride. Hydrolysis of the silanes yields hydrochloric acid which alters the electrical resistance of the potassium chloride solution and this permits quantitative analysis of the silane mixture. 

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