Methyltrimethoxysilane is an organosilicon compound with the formula CH<sub>3</sub>Si(OCH<sub>3</sub>)<sub>3</sub>. It is a colorless, free-flowing liquid. It is a crosslinker in the preparation of polysiloxane polymers.
Methyltrimethoxysilane is usually prepared from methyltrichlorosilane and methanol:
Alcoholysis of alkylchlorosilanes typically proceeds via an S<sub>N</sub>2 mechanism. Inversion of the configuration is favored during nucleophilic attack when displacing good leaving groups, such as chloride. In contrast, displacement of poor leaving groups, such as alkoxide, retention is favored.
Methyltrimethoxysilane is tetrahedral and is often described as sp<sup>3</sup> hybridized. It has idealized C<sub>3v</sub> point symmetry.
Hydrolysis of MTM proceeds both under acidic and basic conditions. Under acid conditions, rates of successive hydrolyses for methyltrimethoxysilane decreases with each step. Under basic condition the opposite is true.