Tetramethylsilane

Description

Tetramethylsilane (TMS1) is the simplest tetraalkylsilane and the organosilicon analogue of neopentane. It is a volatile liquid with a characteristic “organometallic” odor.
TMS has been known since at least 1911, when Artur Bygden at the University of Uppsala (Sweden) prepared it from silicon tetrachloride and the Grignard reagent2 methylmagnesium chloride. Nowadays, TMS is made less expensively, as one of the products of the direct alkylation of elemental silicon with chloromethane.
TMS is sometimes used as a starting material for synthesizing more complex organosilanes, but its main use by far is as a versatile internal standard in NMR spectroscopy. Its 1H, 13C, and 29Si signals are sharp and have resonances that are distinctly different from the nuclei normally encountered in test samples.
For example, the 1H atoms in TMS are highly shielded by the silicon atom and therefore resonate at a higher magnetic field than 1H atoms surrounded by more common nuclei such as carbon, oxygen, and nitrogen. TMS is such a common standard that its 1H chemical shift (δ) is defined as zero. In most 1H spectra, all of the signals are to the left (lower field) of the TMS signal, although highly shielded protons in some aromatic compounds can appear to the right of TMS.
Highly soluble TMS is an ideal standard for generating NMR spectra of samples in organic solvents, but its low water solubility makes it unusable for aqueous samples. TMS’ low cost, chemical inertness, and ease of removal because of its volatility are additional factors that make it the universal standard?for organic-solution NMR.
1. TMS is also used as the abbreviation for the trimethylsilyl radical.
2. Victor Grignard, the French Nobel Prize–winning chemist, had recently discovered the eponymous reaction; and chemists around the world were experimenting with alkylmagnesium halides in all sorts of ways.

Chemical properties

Colorless clear liquid

The Uses of Tetramethylsilane

NMR reference standard. In semiconductor applications (chemical vapor deposition). Tetramethylsilane (TMS) is used as a chemical shift reference for proton, carbon-13, and silicon-29 analysis in organic solvents and is given 0 as its chemical shift position.

The Uses of Tetramethylsilane

Tetramethylsilane is used as a building block in organometallic chemistry. It acts as a by-product in the production of methyl chlorosilanes. Also, it serves as a precursor to silicon dioxide or silicon carbide. It is used as internal reference standard for the calibration of chemical sift for 1, 13 and 29 NMR spectroscopy. In addition, it is used as an aviation fuel.

Definition

ChEBI: Tetramethylsilane is an organosilicon compound that is silane in which the hydrogens have been replaced by methyl groups.

General Description

Tetramethylsilane appears as a colorless, mildly acidic volatile liquid. A serious fire hazard. Mildly toxic by ingestion. Emits acrid smoke and fumes when heated to high temperatures. Less dense than water and insoluble in water, but soluble in most organic solvents. Used as an aviation fuel and as an internal standard for nmr analytical instruments.

Air & Water Reactions

Highly flammable. Tetramethylsilane is insoluble in water.

Reactivity Profile

Hydrides, such as Tetramethylsilane, are reducing agents and react rapidly and dangerously with oxygen and with other oxidizing agents, even weak ones. Thus, they are likely to ignite on contact with alcohols. Hydrides are incompatible with acids, alcohols, amines, and aldehydes.

Hazard

Flammable, high fire risk.

Health Hazard

May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.

Fire Hazard

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Purification Methods

Distil it from conc H2SO4 (after shaking with it) or LiAlH4, through a 5ft vacuum-jacketed column packed with glass helices into an ice-cooled condenser, then percolate it through silica gel to remove traces of halide. [Beilstein 4 IV 3875.]