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Methyltrichlorosilane vapor reacts with water on surfaces to give a thin layer of methylpolysiloxane, which changes the contact angle of the surface to water. This effect arises because of the oriented layer of methyl groups, making a water-repellent film. [ 4 ]
Methyltrichlorosilane can be used to induce branching and cross-linking in PDMS molecules, while chlorotrimethylsilane serves to end backbone chains, limiting molecular weight. Other acid-forming species, especially acetate, can replace chlorine in silicone synthesis with little difference in the chemistry of the finished polymer. These ...
Dimethyldichlorosilane (Me 2 SiCl 2) is of particular value (precursor to silicones), but trimethylsilyl chloride (Me 3 SiCl) and methyltrichlorosilane (MeSiCl 3) are also valuable. [5]: 371 The mechanism of the direct process is still not well understood, despite much research. Copper plays an important role.
Trichlorosilane is a reagent in the conversion of benzoic acids to toluene derivatives. In the first step of a two-pot reaction, the carboxylic acid is first converted to the trichlosilylbenzyl compound. In the second step, the benzylic silyl derivative is converted to the toluene derivative with base. [7]
Methyltrimethoxysilane is usually prepared from methyltrichlorosilane and methanol: CH 3 SiCl 3 + 3 CH 3 OH → CH 3 Si(OCH 3) 3 + 3 HCl. Alcoholysis of alkylchlorosilanes typically proceeds via an S N 2 mechanism. Inversion of the configuration is favored during nucleophilic attack when displacing good leaving groups, such as chloride. [3]
This feature is exploited in many reactions such as the Sakurai reaction, the Brook rearrangement, the Fleming–Tamao oxidation, and the Peterson olefination. [16] The Si–C bond (1.89 Å) is significantly longer than a typical C–C bond (1.54 Å), suggesting that silyl substitutents have less steric demand than their organyl analogues.
The more useful products of this reaction are those for x = 1 (trimethylsilyl chloride), 2 (dimethyldichlorosilane), and 3 (methyltrichlorosilane). [1] TMS undergoes deprotonation upon treatment with butyllithium to give (H 3 C) 3 SiCH 2 Li. The latter, trimethylsilylmethyl lithium, is a relatively common alkylating agent.
The mechanism of the direct synthesis is not known. However, the copper catalyst is essential for the reaction to proceed. In addition to dimethyldichlorosilane, products of this reaction include CH 3 SiCl 3, CH 3 SiHCl 2, and (CH 3) 3 SiCl, which are separated from each other by fractional distillation. The yields and boiling points of these ...