Names | |
---|---|
IUPAC name Trimethoxysilane | |
Other names Trimethoxy silane | |
Identifiers | |
3D model (JSmol) | |
ECHA InfoCard | 100.017.853 |
EC Number |
|
PubChem CID | |
UNII | |
UN number | 9269 |
CompTox Dashboard (EPA) | |
| |
| |
Properties | |
C3H10O3Si | |
Molar mass | 122.195 g·mol−1 |
Appearance | Clear colorless liquid |
Density | 0.86 g/mL Vapor density >1 (vs air) |
Melting point | −115 °C (−175 °F; 158 K) |
Boiling point | 84 °C (183 °F; 357 K) |
Slightly soluble | |
Vapor pressure | < 7.2 mmHg (20 °C) |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Poison inhalation and flammable |
GHS labelling: | |
NFPA 704 (fire diamond) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Trimethoxysilane (TMS) is an organosilicon compound with the formula HSi(OCH3)3. The compound is a commonly used basic raw material for the preparation of silicone materials.
Trimethoxysilane can be produced in a complicated synthesis. This synthesis includes steps such as, using a wet chemical reduction method to prepare nano-copper. Then preparing a silicon powder-nano-copper catalyst mixture, which is followed by preparing trimethoxysilane by a fixed bed reactor. This trimethoxysilane synthesis is suitable for industrialized production as the synthesis is simple and convenient to operate. [3]
There are multiple synthesis methods of trimethoxysilane, which includes the direct synthesis of trialkoxysilane. The direct synthesis is a reaction of silicon and alcohol. This reaction takes place in a solvent with the presence of a catalytically effective amount of direct synthesis catalyst and an effective catalyst-promoting amount of direct synthesis catalyst promoter. This promoter is often an organic or inorganic compound possessing at least one phosphorus-oxygen bond. [4]
Trimethoxysilane is an important substance for producing silane coupling agents. It contains both hydrolyzable siloxane bonds as well as an active silicon-hydrogen bond. Thereby it can be utilized in a series of reactions, such as copolymerization, polycondensation, and disproportionation reactions. These reactions have many possible downstream products which are used to manufacture diverse coupling agents, silylating substances for plastic surfaces, and reagents for thermal insulation production.
The plastic industry makes use of certain organic coupling agents, like adhesion promoters, which can thus be manufactured from trimethoxysilane. An example is trimethoxysilylpropyl methacrylate, which is produced by direct addition of trimethoxy silane to the 3-methacryloxypropyl group in the presence of radical scavengers. The resulting compound plays an important role in organosiloxane copolymers, prosthetics, and contact lenses. Besides that it can also work as coupling or silylating agent in other reactions.
A silane coupling agent acts as a sort of intermediary which bonds organic materials to inorganic materials. It is this characteristic that makes silane coupling agents useful for improving the mechanical strength of composite materials, for improving adhesion, and for resin and surface modification.
TMS is used as an adhesive and binding agent (92%), as an intermediate (7%) and as a surface active agent (1%). Due to its high reactivity, trimethoxysilane is produced and used as site-limited intermediate in closed systems. This limits the potential for exposure. [5] [6]
Trimethoxysilane is a dermatotoxin. Exposure can occur via inhalation or skin or eye contact. In case of inhalation of trimethoxysilane, a typical effect is respiratory tract irritation, which can be fatal. Toxic vapors can cause inflammation of the lungs and even pneumonitis. The patient can be treated by clearing the airways and administering an oxygen mask. When vapors come in contact with the eyes, this can cause irritation or even blindness when it is absorbed into the corneal tissues. In case of eye contamination, immediately flushing with water is desired. TMS can also be absorbed via skin, causing skin irritation. This can be treated by rinsing with flowing water as well. High exposure to TMS may cause other physical problems like headache, drowsiness and seizure, which eventually can be fatal. [7]
The effects of trimethoxysilane were also tested on rats. Exposure to the rats eyes had the same effect as in humans. It causes eye irritation and damage of the cornea and conjunctiva. The efficacy of trimethoxy was tested on rats and rabbits. When administered orally in rats, the median lethal dose (LD50) is estimated to be 1560 μL/kg. The lethal dose or lethal concentration is the amount of chemical at which 50% of the test group of animals dies. Via inhalation, the lethal concentration (LC50) is 42 ppm/4h. Finally, the LD50 in rabbits is 6300 μL/kg when administered via the skin. [8]
Trimethoxysilane has a relatively high vapor pressure of 76 Hg at 25 °C which means that it is solely present in the gas phase in the atmosphere. [9] It can either be hydrolyzed immediately, or degraded via reaction with hydroxyl radicals in the air. The half-life for the latter reaction is calculated to be 6.4 days. TMS itself is not expected to be susceptible to direct photolysis by sunlight. If TMS is hydrolyzed in air, this occurs within 3 minutes at 25 °C, which is much faster. Hydrolysis of TMS can also occur in water, but at a 10 times slower rate than in air: 0.3 minutes at 2 °C. Hydrolysis of TMS produces methanol and silanetriol at a ratio of 3:1. The produced silane triol can undergo further condensation, which results in either siloxane polymers or monomers depending on the concentration. [10]
Tabun is an extremely toxic compound of the organophosphate family. It is not present in nature. At room temperature, the pure compound presents itself as a clear and viscous liquid. However, impurities imparted during its manufacture are almost always present in some amount, turning it into a yellow or brown liquid. Exposed to environs, it slowly volatizes into the atmosphere, with the vapor having a slight fruity or almond-like odor. As the compound has a much higher molecular mass compared to air, Tabun gas tends to accumulate in low-lying areas.
Silane (Silicane) is an inorganic compound with chemical formula SiH4. It is a colorless, pyrophoric, toxic gas with a sharp, repulsive, pungent smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Silane with alkyl groups are effective water repellents for mineral surfaces such as concrete and masonry. Silanes with both organic and inorganic attachments are used as coupling agents. They are commonly used to apply coatings to surfaces or as an adhesion promoter.
A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom [−Si(CH3)3], which is in turn bonded to the rest of a molecule. This structural group is characterized by chemical inertness and a large molecular volume, which makes it useful in a number of applications.
The Bamford–Stevens reaction is a chemical reaction whereby treatment of tosylhydrazones with strong base gives alkenes. It is named for the British chemist William Randall Bamford and the Scottish chemist Thomas Stevens Stevens (1900–2000). The usage of aprotic solvents gives predominantly Z-alkenes, while protic solvent gives a mixture of E- and Z-alkenes. As an alkene-generating transformation, the Bamford–Stevens reaction has broad utility in synthetic methodology and complex molecule synthesis.
Cyanogen bromide is the inorganic compound with the formula (CN)Br or BrCN. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds. The compound is classified as a pseudohalogen.
Organosilicon chemistry is the study of organometallic compounds containing carbon–silicon bonds, to which they are called organosilicon compounds. Most organosilicon compounds are similar to the ordinary organic compounds, being colourless, flammable, hydrophobic, and stable to air. Silicon carbide is an inorganic compound.
Tetrafluorohydrazine or perfluorohydrazine, N2F4, is a colourless, nonflammable, reactive inorganic gas. It is a fluorinated analog of hydrazine.
Benzotrichloride (BTC), also known as α,α,α-trichlorotoluene, phenyl chloroform or (trichloromethyl)benzene, is an organic compound with the formula C6H5CCl3. Benzotrichloride is an unstable, colorless or somewhat yellowish, viscous, chlorinated hydrocarbon with a penetrating odor. Benzotrichloride is used extensively as a chemical intermediate for products of various classes, i.e. dyes and antimicrobial agents.
Hydrosilanes are tetravalent silicon compounds containing one or more Si-H bond. The parent hydrosilane is silane (SiH4). Commonly, hydrosilane refers to organosilicon derivatives. Examples include phenylsilane (PhSiH3) and triethoxysilane ((C2H5O)3SiH). Polymers and oligomers terminated with hydrosilanes are resins that are used to make useful materials like caulks.
Tetraethyl orthosilicate, formally named tetraethoxysilane (TEOS), ethyl silicate is the organic chemical compound with the formula Si(OC2H5)4. TEOS is a colorless liquid. It degrades in water. TEOS is the ethyl ester of orthosilicic acid, Si(OH)4. It is the most prevalent alkoxide of silicon.
Mercuric amidochloride is an inorganic compound with the formula Hg(NH2)Cl.
Methyltrichlorosilane, also known as trichloromethylsilane, is a monomer and organosilicon compound with the formula CH3SiCl3. It is a colorless liquid with a sharp odor similar to that of hydrochloric acid. As methyltrichlorosilane is a reactive compound, it is mainly used a precursor for forming various cross-linked siloxane polymers.
p-Chlorocresol, or 4-chloro-3-methylphenol (ClC6H3CH3OH), also known as p-chloro-m-cresol, is a potent disinfectant and antiseptic. It appears as a pinkish white crystalline solid. It is also used as a preservative in cosmetics and medicinal products for both humans and animals. It is used as an active ingredient in some preparations of veterinary medicines for tropical, oral and parenteral use. Normally, the concentration of p-Chlorocresol in oral and parenteral veterinary products are 0.1-0.2%. Concentrations are higher (~0.5%) in tropical veterinary products. p-Chlorocresol contains microbial activity against both gram positive and gram negative bacteria and fungi.
Hexachlorocyclopentadiene (HCCPD), also known as C-56, Graphlox, and HRS 1655, is an organochlorine compound with the formula C5Cl6. It is a precursor to pesticides, flame retardants, and dyes. It is a colourless liquid, although commercial samples appear lemon-yellow liquid sometimes with a bluish vapour. Many of its derivatives proved to be highly controversial, as studies showed them to be persistent organic pollutants. An estimated 270,000 tons were produced until 1976, and smaller amounts continue to be produced today.
Demeton, sold as an amber oily liquid with a sulphur like odour under the name Systox, is an organophosphate derivative causing irritability and shortness of breath to individuals repeatedly exposed. It was used as a phosphorothioate insecticide and acaricide and has the chemical formula C8H19O3PS2. Although it was previously used as an insecticide, it is now largely obsolete due to its relatively high toxicity to humans. Demeton consists of two components, demeton-S and demeton-O in a ratio of approximately 2:1 respectively. The chemical structure of demeton is closely related to military nerve agents such as VX and a derivative with one of the ethoxy groups replaced by methyl was investigated by both the US and Soviet chemical-weapons programs under the names V-sub x and GD-7.
Disiloxane has the chemical formula Si
2H
6O. It is the simplest known siloxane with hydrogen only R groups. The molecule contains six equivalent Si−H bonds and two equivalent Si−O bonds. Disiloxane exists as a colorless, pungent gas under standard conditions. However, it is generally safe for human use as evidence in its widespread use in cosmetics. It is also commonly known as disilyl ether, disilyl oxide, and perhydrodisiloxane
Methacrylonitrile, MeAN in short, is a chemical compound that is an unsaturated aliphatic nitrile, widely used in the preparation of homopolymers, copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, amines, esters, and other nitriles. MeAN is also used as a replacement for acrylonitrile in the manufacture of an acrylonitrile/butadiene/styrene-like polymer. It is a clear and colorless liquid, that has a bitter almond smell.
Methacrolein diacetate is a chemical compound with the molecular formula C8H12O4 and a molecular weight of 172.17848. It is a colorless liquid. It is listed as an extremely hazardous substance by the Emergency Planning and Community Right-to-Know Act, and the National Institute of Health identifies it as "an irritant of the eyes, skin, and respiratory tract."
Lewisite 2(L-2) is an organoarsenic chemical weapon with the formula AsCl(CH=CHCl)2. It is similar to lewisite 1 and lewisite 3 and was first synthesized in 1904 by Julius Arthur Nieuwland. It is usually found as a mixture of 2-chlorovinylarsonous dichloride (lewisite 1) as well as bis(2-chloroethenyl) arsinous chloride (lewisite 2) and tris(2-chlorovinyl)arsine (lewisite 3). Pure lewisite 1 is an oily, colorless liquid, however, the impure mixture can appear amber to black with an odor distinct to geraniums.
Lewisite 3(L-3) is an organoarsenic chemical weapon like lewisite 1 and lewisite 2 first synthesized in 1904 by Julius Arthur Nieuwland. It is usually found as a mixture of 2-chlorovinylarsonous dichloride as well as bis(2-chloroethenyl) arsinous chloride and tris(2-chlorovinyl)arsine. Pure lewisite 1 is an oily, colorless liquid, however, the impure mixture can appear amber to black with an odor distinct to geraniums.