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|Section2= |Section3= |Section8= }} Tetramethyl orthosilicate is the chemical compound with the formula Si(OCH3)4. This molecule consists of four methyl groups attached to the hypothetical anion SiO44−. 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: :Si(OCH3)4 + 2 H2O → SiO2 + 4 CH3OH In organic synthesis, Si(OCH3)4 has been used to convert ketones and aldehydes to the corresponding ketals and acetals, respectively.〔Sakurai, H. "Silicon(IV) Methoxide" in Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley & Sons. 〕 ==Safety== The hydrolysis of Si(OCH3)4 produces insoluble SiO2 and CH3OH (methanol). Even at low concentrations inhalation causes lung lesions, and at slightly higher concentrations eye contact with the vapor causes blindness. Worse, at low concentrations (200ppm/15min) the damage is often insidious, with onset of symptoms hours after exposure. The mode of action is the precipitation of silica in the eyes and/or lungs. Contrary to common information, including several erroneous MSDS sheets, the methanol produced is relatively innocuous. The mechanisms of methanol toxicity are well established, methanol causes blindness via conversion to toxic formaldehyde in the liver; methanol splashes to the eye cause only moderate and reversible eye irritation. Tetraethyl orthosilicate is safer for two reasons. 1) It is considerably less volatile. 2) It is hydrolyzed more slowly by the water in the lungs and on the eyes (due to steric bulk). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tetramethyl orthosilicate」の詳細全文を読む スポンサード リンク
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