Trimethylsilyl acetate, also known as TMSOAc, is an organosilicon compound with the chemical formula . It is a colorless liquid. It is the silyl ester analog of tert-butyl acetate, having a trimethylsilyl group in place of the tert-butyl group .
Trimethylsilyl acetate can be prepared by the reaction of trimethylsilyl chloride with sodium acetate in hexanes or diethyl ether in the presence of a phase-transfer catalyst to speed up the reaction.
A trimethylsilyl acetate and methane mixture can be used to produce a-C:H:SiO<sub>x</sub> coatings using plasma-enhanced chemical vapor deposition (PECVD), which have a hardness of up to 11 GPa.
Other coatings can be produced with a trimethylsilyl acetate and oxygen mixture, again using PECVD.
Trimethylsilyl acetate can also be used for acetylation of alcohols.