General Description
A colorless liquid with a pungent odor. Flash point of 193°F. Decomposed by water to hydrochloric acid with the evolution of heat. Corrosive to metals and tissue. Used to make various silicon containing compounds.
Reactivity Profile
Chlorosilanes, such as OCTADECYLTRICHLOROSILANE, are compounds in which silicon is bonded to from one to four chlorine atoms with other bonds to hydrogen and/or alkyl groups. Chlorosilanes react with water, moist air, or steam to produce heat and toxic, corrosive fumes of hydrogen chloride. They may also produce flammable gaseous H2. They can serve as chlorination agents. Chlorosilanes react vigorously with both organic and inorganic acids and with bases to generate toxic or flammable gases.
Health Hazard
TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Contact with molten substance may cause severe burns to skin and eyes. 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
Combustible material: may burn but does not ignite readily. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. When heated, vapors may 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. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
Chemical Properties
Colorless clear liquid
Uses
n-Octadecyltrichlorosilane is used in semiconductor industry to form self-assembled monolayer thin films on silicon dioxide substrates. Used in molecular electronics, as thin insulating gates in Metal-Insulator-Semiconductor Field-Effect Transistors. It is also used in platinum catalyzed synthesis.
Purification Methods
Purify it by fractional distillation at high vacuum. [Winstein & Seubold J Am Chem Soc 69 2916 1947, Beilstein 4 IV 4256.]
