Topic summary
Tetramethyl orthosilicate
Tetramethyl orthosilicate (TMOS) is the chemical compound with the formulaSi(OCH3)4. This molecule consists of four methoxy groups bonded to a silicon atom. It is the tetramethylester of orthosilicic acid. The basic properties are similar to the more popular tetraethyl orthosilicate, which is usually preferred because the product of hydrolysis, ethanol, is less toxic than methanol.
Tetramethyl orthosilicate hydrolyzes to SiO2:
In organic synthesis, Si(OCH3)4 has been used to convert ketones and aldehydes to the corresponding ketals and acetals, respectively.