Тетраметилортосиликат

Химические свойства

Tetramethyl orthosilicate (TMOS), the methyl ester of orthosilicic acid, is a colorless, low-viscosity liquid. It is industrially the most important of the tetraalkyl silicates.

Использование

Tetramethyl Orthosilicate is a compound used in the research of the multifunctionality of silicified nanoshells and the efficiency at adsorbing cadmium ions at cell interfaces.

Методы производства

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.

Общее описание

A clear colorless liquid. Flash point below 125°F. Less dense than water and insoluble in water. Very toxic by ingestion and inhalation and very irritating to skin and eyes. Used to make paints and lacquers.

Реакции воздуха и воды

Flammable. Insoluble in water.

Профиль реактивности

Tetramethyl orthosilicate is incompatible with the following: Oxidizers; hexafluorides of rhenium, molybdenum & tungsten .

Опасность

Eye damage and upper respiratory tract irri-tant.

Угроза здоровью

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.

Пожароопасность

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.

Профиль безопасности

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.

Возможный контакт

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.

Перевозки

UN2606 Methyl orthosilicate, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 3-Flammable liquid.

Методы очистки

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.]

Несовместимости

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.