681-84-5 Usage
Description
Tetramethyl orthosilicate (TMOS) is a colorless, low-viscosity liquid and the methyl ester of orthosilicic acid. It is a chemical compound with the formula Si(OCH3)4, consisting of four methoxy groups bonded to a silicon atom. TMOS is more reactive and hydrolyzes faster than its counterpart tetraethyl orthosilicate (TEOS), making it a popular choice in various applications. However, it is also more toxic than TEOS and has a flash point below 125°F. It is less dense than water, insoluble in water, and very toxic by ingestion and inhalation, as well as very irritating to skin and eyes.
Uses
Used in Sol-Gel Synthesis:
Tetramethyl orthosilicate is used as a precursor in the sol-gel synthesis of silicates and chromium-doped silicates, as well as in the formation of hexagonal mesoporous silica layers. The hydrolysis and condensation reactions of TMOS allow for the creation of a wide range of materials with unique properties.
Used in Electronics Industry:
TMOS is used as a coating for screens of television picture tubes, providing protection and enhancing performance.
Used in Manufacturing Industry:
Tetramethyl orthosilicate serves as a mold binder in various manufacturing processes, improving the quality and durability of the final products.
Used in Corrosion Protection:
TMOS is used in the development of corrosion-resistant coatings, helping to protect materials from environmental damage and extending their lifespan.
Used in Catalyst Preparation:
Tetramethyl orthosilicate is utilized in the preparation of catalysts, which are essential in various chemical reactions and industrial processes.
Used in Silicone Production:
TMOS acts as an intermediate in the production of silicone materials, contributing to the development of a diverse range of silicone-based products.
Used in Environmental Research:
Tetramethyl orthosilicate is employed in research focused on the multifunctionality of silicified nanoshells and their efficiency at adsorbing cadmium ions at cell interfaces, potentially contributing to environmental remediation and protection.
Used in Paint and Lacquer Industry:
TMOS is used in the production of paints and lacquers, improving their properties and performance in various applications.
Production Methods
Silica aerogels are usually prepared by base-catalyzed reaction
of tetramethoxysilane or tetraethoxysilane, mostly with
ammonia as the catalyst. A modification of this procedure is
to prehydrolyze Si(OR)4 with a small amount of water under
acidic conditions.
Air & Water Reactions
Flammable. Insoluble in water.
Reactivity Profile
Tetramethyl orthosilicate is incompatible with the following: Oxidizers; hexafluorides of rhenium, molybdenum & tungsten .
Hazard
Eye damage and upper respiratory tract irri-tant.
Health Hazard
TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Bromoacetates and chloroacetates are extremely irritating/lachrymators. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Fire Hazard
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapors may travel to source of ignition and flash back. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
Flammability and Explosibility
Flammable
Safety Profile
Poison by
intraperitoneal route. Moderately toxic by
inhalation. Midly toxic by skin contact. A
severe eye irritant. This material can cause extensive necrosis (experimentally),
keratoconus, and opaque cornea. It also
causes severe human eye injuries, as well as
necrosis of corneal cells, which progresses
long after exposure has ceased. It is
destructive and its effects resist treatment.
Permanent blindness is possible from
exposure to it. The kidney seems to be most
subject to injury regardless of the mode of
exposure. Pulmonary edema has also
occurred. This material is more toxic than
either ethyl silicate or silicic acid, although it
has been thought that the injury caused is
largely due to the action of the silicic acid.
Flammable when exposed to heat or flame;
can react vigorously with oxidizing
materials. Potentially violent reaction with
metal hexafluorides (e.g., rhenium,
molybdenum, tungsten). When heated to
decomposition it emits acrid smoke and
irritating fumes.
Potential Exposure
Methyl silicate is used in coating
screens of television picture tubes. It may be used in mold
binders and in corrosion-resistant coatings; as well as in
catalyst preparation and as a silicone intermediate.
Shipping
UN2606 Methyl orthosilicate, Hazard class: 6.1;
Labels: 6.1-Poisonous materials, 3-Flammable liquid.
Purification Methods
Purification is as for tetraethoxysilane. It has a vapour pressure of 2.5mm at 0o. [IR: Sternbach & MacDiarmid J Am Chem Soc 81 5109 1959. Beilstein 1 IV 1266.]
Incompatibilities
Vapor may form explosive mixture with
air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep
away from alkaline materials, including alkaline earth
metals, metals, strong acids, strong bases; water, moisture,
steam decomposes releasing toxic, flammable gases.
Violent reaction with metal hexafluorides of rhenium,
molybdenum, and tungsten. Contact with metals may
evolve flammable hydrogen gas.
Check Digit Verification of cas no
The CAS Registry Mumber 681-84-5 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 6,8 and 1 respectively; the second part has 2 digits, 8 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 681-84:
(5*6)+(4*8)+(3*1)+(2*8)+(1*4)=85
85 % 10 = 5
So 681-84-5 is a valid CAS Registry Number.
InChI:InChI=1/C2H6O3Si/c1-4-6(3)5-2/h1-2H3
681-84-5Relevant articles and documents
Direct Transformation of Silica into Alkoxysilanes by Gas-Solid Reactions
Suzuki, Eiichi,Akiyama, Masanari,Ono, Yoshio
, p. 136 - 137 (1992)
Silica gel is conveniently and efficiently converted into tetramethoxysilane by treatment with gaseous dimethyl carbonate at 500-600 K in the presence of an alkali hydroxide catalyst supported on the reacting silica.
The study of an alcoholysis reaction of silicon tetrafluoride with alcohols and magnesium to prepare tetraalkoxysilanes and magnesium fluoride
Zhang, Zongfan,Huang, Zhong,Tian, Qiang,Li, Yuye,Li, Xia,Liang, Xuesong,Du, Lusha
, p. 567 - 573 (2015)
An efficient alcoholysis reaction of silicon tetrafluoride with alcohols in the presence of magnesium can directly prepare tetraalkoxysilane and magnesium fluoride. The reaction can afford tetraethoxysilane, tetramethoxysilane, and magnesium fluoride in good yields with the aid of a catalytic amount of iodine.
-
Rochow
, p. 2170 (1948)
-
Mechanochemistry-a new powerful green approach to the direct synthesis of alkoxysilanes
Temnikov, Maxim N.,Anisimov, Anton A.,Zhemchugov, Pavel V.,Kholodkov, Dmitry N.,Goloveshkin, Alexander S.,Naumkin, Alexander V.,Chistovalov, Sergey M.,Katsoulis, Dimitris,Muzafarov, Aziz M.
, p. 1962 - 1969 (2018)
The present work shows a new one-stage mechanochemical method for the direct synthesis of alkoxysilanes by silicon mechanoactivation followed by a reaction with an alcohol. Alkoxysilanes were obtained with nearly complete silicon and alcohol conversion. This method allows for a considerable simplification of the traditional multistage process by eliminating three stages that include silicon and catalyst preparation, and adapts it to green chemistry requirements. Vibration milling removed the oxide film, and the mechanoactivation of the large silicon fraction (1000-2000 μm) occurs in the reactor working space. Abrasion of the reactor walls and grinding bodies made of brass results in a developed catalytic surface on silicon, as it has been proven by a set of physical analytical methods such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD), and X-ray photoelectron spectroscopy (XPS).
Method for preparing organosilane by utilizing organosilicone byproduct
-
Paragraph 0024, (2020/07/13)
The invention relates to the technical field of production of organic silicon by-products. The invention aims to solve the problems of high cost, more three wastes and continuous production of byproducts in the traditional organic silicon byproduct treatment process. The method comprises the following steps: adding the organic silicon by-product into a nitrogen-protected glass lining reaction kettle with a tower, adding a catalyst, dropwise adding alcohol to the bottom of the glass lining reaction kettle, carrying out a heating reaction under a stirring condition, neutralizing the obtained material, and rectifying the neutralized material to obtain the organic silane. According to the method, the multi-component organic silicon by-products trichlorosilane and silicon tetrachloride react and are converted into the same product, the high-purity product can be obtained only through simple rectification and purification, the process is simple, the treatment cost is low, and the product hasgood economic value.
Direct transformation of silica from natural resources to form tetramethoxysilane
Putro, Wahyu S.,Fukaya, Keisuke,Choi, Jun-Chul,Choi, Seong Jib,Horikoshi, Toshio,Sato, Kazuhiko,Fukaya, Norihisa
, p. 958 - 962 (2020/09/04)
A simple and practical method for direct synthesis of tetramethoxysilane (TMOS) from silica (SiO2) and methanol was achieved using a base catalyst and acetal as a dehydrant under carbon dioxide (CO2). The production of TMOS was strongly influenced by the kind of the acetal used, with 2,2-dimeth-oxypropane identified as the most effective dehydrant. We observed that the acetal used enabled the production of a high yield of dimethyl carbonate (DMC), which promoted the TMOS production. DMC is an intermediate product from the reaction of CO2 and methanol, which supported the SiO2 depolymerization process. When the reaction is conducted with 2,2-dimethoxypropane at 260 °C for 24 h, TMOS can be produced in up to 59percent yield. For practical applications, the TMOS synthesis has been developed on a 250 mL and 1 L-scale reaction with constant yield (>50percent) from various silica resources.