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Dimethyldichlorosilane is a tetrahedral organosilicon compound with the formula Si(CH 3) 2 Cl 2. At room temperature it is a colorless liquid that readily reacts with water to form both linear and cyclic Si-O chains. Dimethyldichlorosilane is made on an industrial scale as the principal precursor to dimethylsilicone and polysilane compounds.
Tetramethylsilane is the accepted internal standard for calibrating chemical shift for 1 H, 13 C and 29 Si NMR spectroscopy in organic solvents (where TMS is soluble). In water, where it is not soluble, sodium salts of DSS, 2,2-dimethyl-2-silapentane-5-sulfonate, are used instead.
The chemical formula of PDMS is CH 3 [Si(CH 3) 2 O] n Si(CH 3) 3, where n is the number of repeating monomer [Si(CH 3) 2 O] units. [4] Industrial synthesis can begin from dimethyldichlorosilane and water by the following net reaction: n Si(CH 3) 2 Cl 2 + (n+1) H 2 O → HO[Si(CH 3) 2 O] n H + 2n HCl. The polymerization reaction evolves ...
This group consists of three methyl groups bonded to a silicon atom [−Si(CH 3) 3], which is in turn bonded to the rest of a molecule. This structural group is characterized by chemical inertness and a large molecular volume , which makes it useful in a number of applications.
2 CH 3 Cl + Si → (CH 3) 4−n SiCl n + other products. While this reaction is the standard in industrial silicone production and is nearly identical to the first direct synthesis of methyltrichlorosilane, the overall process is inefficient with respect to methyltrichlorosilane. [2]
The S(N(Si(CH 3) 3) 2) 2 reacts with the combination of SCl 2 and sulfuryl chloride (SO 2 Cl 2) to form S 4 N 4, trimethylsilyl chloride, and sulfur dioxide: [5] 2 S(N(Si(CH 3 ) 3 ) 2 ) 2 + 2 SCl 2 + 2 SO 2 Cl 2 → S 4 N 4 + 8 (CH 3 ) 3 SiCl + 2 SO 2
The mechanism begins by generation of Si(CH 3) 3 X and a highly reactive [CF 3] − (trifluoromethide) intermediate. The [CF 3 ] − attacks the carbonyl to generate an alkoxide anion. The alkoxide is silylated by the reagent to give the overall addition product, plus [CF 3 ] − , thus propagating an anionic chain reaction.
The relevant reactions are (Me = CH 3): x MeCl + Si → Me 3 SiCl, Me 2 SiCl 2, MeSiCl 3, Me 4 Si 2 Cl 2, ... Dimethyldichlorosilane (Me 2 SiCl 2) is of particular value as a precursor to silicones, but trimethylsilyl chloride (Me 3 SiCl) and methyltrichlorosilane (MeSiCl 3) are also valuable.