Silylation
Under silylation is meant chemical reactions in organic chemistry, in which the products of derivatives of silanes are derived ( derivatization ). Silylation with the formation of a siloxane bond (Si-O-Si) is of particular importance in the production of silicone materials . The silylation of hydroxyl groups in alcohols takes place with alkyl or aryl silicon chlorides and is an important functionalization in organic chemistry. Since the silyl group can be split off again very easily from the products formed, it is also referred to here as the protective group . The silylation of enols with trimethylchlorosilane (abbreviated TMS – Cl) yields TMS-protected enols. A related reaction is hydrosilylation , in which derivatives of hydrosilanes are converted by a catalytic addition reaction on vinyl groups or other multiple bonds. Typical catalysts are complexes of the noble metal platinum . This type of reaction is widely used in rubber production .
For many substance classes such as B. carbohydrates , long-chain alcohols , phenols , sterols , steroids and fatty acids , silyl derivatives play a significant role in gas chromatographic analysis , since the derivatives produced can usually be evaporated without decomposition and can be easily separated, especially on non-polar stationary phases .
Silylating agents
- Aminopropyltriethoxysilane (APTES)
- Dichlorodimethylsilane
- Chlorotrimethylsilane
- Chlorotriphenylsilane
- Hexamethyldisilazane
- N -Methyl- N - (trimethylsilyl) trifluoroacetamide (MSTFA)
- N , O -Bis (trimethylsilyl) acetamide (BSA)
- N , O -Bis (trimethylsilyl) trifluoroacetamide (BSTFA)
- N -trimethylsilyl-diethylamine (TMS-DEA)
Bibliography
- Udo Michel: Silylation and catalytic amination of cellulose in ammonia. Dissertation . Shaker, Aachen 2001, ISBN 3-8265-9643-9 .
Individual evidence
- ^ A b Siegfried Hauptmann : Organic chemistry. 2nd Edition. VEB Deutscher Verlag für Grundstofftindustrie, Leipzig 1985, ISBN 3-342-00280-8 , p. 551.
- ^ Daniel R. Knapp: Handbook of Derivatization Reactions. John Wiley & Sons, New York / Chichester / Brisbane / Toronto 1979, ISBN 0-471-03469-X .