| 词条 | Tetramethyl orthosilicate |
| 释义 |
| Watchedfields = changed | verifiedrevid = 470604767 | ImageFileL1 = Tetramethyl orthosilicate.svg | ImageFileR1 = Tetramethyl orthosilicate 3D.png | IUPACName = tetramethoxysilane | OtherNames = tetramethyl orthosilicate; methyl silicate; silicic acid, tetramethyl ester; silicon methoxide; TMOS |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 12161 | InChI = 1/C4H12O4Si/c1-5-9(6-2,7-3)8-4/h1-4H3 | InChIKey = LFQCEHFDDXELDD-UHFFFAOYAT | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C4H12O4Si/c1-5-9(6-2,7-3)8-4/h1-4H3 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = LFQCEHFDDXELDD-UHFFFAOYSA-N | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 681-84-5 | PubChem = 12682 | SMILES = CO[Si](OC)(OC)OC }} |Section2={{Chembox Properties | Formula = SiC4H12O4 | MolarMass = 152.25 | Appearance = colourless liquid | Density = 1.032 | MeltingPtC = 4 to 5 | MeltingPt_notes = | BoilingPtC = 121 to 122 | Solubility = organic solvents | VaporPressure = 12 mmHg (25°C)[1] |Section3={{Chembox Hazards | MainHazards = toxic | FlashPtF = 205 | FlashPt_notes =[1] | AutoignitionPt = | IDLH = N.D.[1] | PEL = none[1] | REL = TWA 1 ppm (6 mg/m3)[1] |Section8={{Chembox Related | OtherCations = Trimethyl borate Trimethyl phosphite }} Tetramethyl orthosilicate is the chemical compound with the formula Si(OCH3)4. This molecule consists of four methoxy groups bonded to a silicon atom. 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.[2] SafetyThe 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{{Citation needed|date=June 2018}}. Worse, at low concentrations (200 ppm/15 min) the damage is often insidious, with onset of symptoms hours after exposure.[3] The mode of action is the precipitation of silica in the eyes and/or lungs{{Citation needed|date=June 2018}}. Contrary to common information, including several erroneous MSDS sheets, the methanol produced is relatively innocuous{{Citation needed|date=June 2018}}. 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.[4] References1. ^1 2 3 4 {{PGCH|0428}} 2. ^Sakurai, H. "Silicon(IV) Methoxide" in Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley & Sons. {{doi|10.1002/047084289X.rs012}} 3. ^{{cite web|title=Tetramethyl silicate|url=http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~v3cqfN:1:FULL|work=National Library of Medicine - Hazardous Substances Data Bank|publisher=National Library of Medicine|accessdate=11 February 2013}} 4. ^{{cite web|title=Methanol|url=http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~Bjt41r:1|work=Hazardous Substances Data Bank - National Library of Medicine|publisher=National Library of Medicine|accessdate=11 February 2013}} External links
2 : Methyl esters|Silicate esters |
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