Trimethylsilanol

• Hydroxytrimethylsilan
• Trimethylhydroxysilan

Colorless clear liquid

Liquid

0.95 g · cm -3

-4.5 ° C

98 ° C

21 mbar ( 20 ° C)

35-43 g · l - 1 in water

Risk

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Trimethylsilanol (TMS ) is a chemical compound and belongs to the silanols. It is a derivative of the silane and the silicon analog of tert- butanol.

Representation and extraction

Simple hydrolysis of chlorotrimethylsilane leads because of the by-product hydrochloric acid rather to etherification hexamethyldisiloxane. Through a slightly basic hydrolysis performed trimethylsilanol is accessible, so as the dimerization can be avoided. Trimethylsilanol can also be obtained by the basic hydrolysis of hexamethyldisiloxane.

Properties

Trimethylsilanol is a volatile organic liquid having a boiling point of 98 ° C. The heat of vaporization of 45.64 kJ · mol -1, the vaporization 123 J · K-1 · mol -1. The vapor pressure function is given by Antoine corresponding log10 (P) = A- ( B / ( T C )) ( P in bar, T in K) with A = 5.44591, B = 1767.766 and C = -44.888 in temperature range of 291 K to 358 K below the melting point at -4.5 ° C the solidified compound in a monoclinic crystal lattice. Trimethylsilanol is a weak acid with a pKa of 11. The acid strength is comparable with that of the ortho-silicic acid, but substantially higher than the case of alcohols such as tert.-butanol (pKa 19).

Use

TMS is used for the hydrophobic coating on the silicate surface. It reacts with the silicon atoms of the substrate thereby forming a layer of the methylene groups is formed. TMS usually occurs as an impurity in spaceships because it releases gases from the silicone -based materials.

Like other silanols is investigated for use as an antimicrobial agent TMS.

TMS is a possible hydrolysis of PDMS chain end groups.