The synthesis of -substituted dialkyldichlorosilanes and their conversion into polysiloxanes

Article abstract of DOI:10.1016/0022-1139(93)02917-4

Attack of the oxyl (CF3)2NO^. (1) on an ethyl group of the silane Et2SiCl2 occurs at both the α- and β-positions relative to silicon (ratio 31:45), whereas with the silane PrⁿSiMeCl2 attack takes place at the β-position of the propyl group.With the disilane Me3SiCH2SiMe3, the mojor silicon-containing products formed from treatment with oxyl 1 are Me3SiF, (CF3)2NOSiMe3 and Me3SiSiMe3.Speier-catalysed (H2PtCl6) addition of the silane HSiCl2X (X = Me and Cl) to the alkene (CF3)2NOCH2CH=CH2 gives the adducts (CF3)2NOCH2CH2CH2SiCl2X (29, X = Me) and (28, X = Cl)in high yield.The substituted dichlorosilanes (CF3)2NOCH2CH2SiEtCl2 (9), (CF3)2NOCHMeCH2SiMeCl2 (14) and (CF3)2NOCH2CH2CH2SiMeCl2 (29) are converted into corresponding polysiloxanes ("prepolymers" of low molecular weight) by reaction with reagents including water, acid, base and metal oxides; equilibration of the polysiloxane "prepolymer" 38, derived from dichlorosilane 29 by heating with powdered KOH, affords a solid rubbery polysiloxane.