Generation and capture of alkylchlorosilanones

Alkyltrichlorosilanes react with DMSO (molar ratio 1 : 1 0 °C) to give cyclic oligoalkylchlorosiloxanes of the general formula [R(Cl)SiO] _n (where R=Me or Et;n=3–6). With an excess of alkyltrichlorosilane (2: 1), linear oligoalkylchlorosiloxanes Cl[R(Cl)SiO] _m SiCl₂R (where R=Me or Et;m=1–5) are also formed. In the presence of hexamethyldisiloxane (molar ratio Cl₃SiR : DMSO: (Me₃Si)₂O=1:1:2, 20 °C), the reaction products are both cyclic and linear oligoalkyl(trimethylsilyloxy)siloxanes [R(Me₃SiO)SiO] _n (n=3–5) and Me₃Si[OSi(OSiMe₃)R] _m OSiMe₃ (m=1–3), respectively. The reaction of DMSO with trichloro(vinyl)silane and hexamethyldisiloxane occurs in a similar manner. A plausible scheme of formation of the final products via intermediate alkylchlorosilanones RClSi=O and alkyl(trimethylsilyloxy)silanones is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 361–364, February, 2000.