I. A. Gebel

Reaction of Organylchlorosilanes with Dimethyl Sulfoxide in the Presence of Octamethyltrisiloxane

Dichloro(methyl)(vinyl)silane reacts with DMSO in the presence of octamethyltrisiloxane to form cyclooligomethyl(vinyl)siloxanes(MeViSiO)n (n = 3-6). The reaction involves disproportionation of octamethyltrisiloxane into hexamethyldisiloxane and decamethyltetrasiloxane. Along with the latter two products, insertion products of methyl vinyl silanone into both permethyloligosiloxanes were identified. Alkyltrichlorosilanes RSiCl3 (R = Me, Et) react with DMSO in the presence of octamethyltrisiloxane to form cyclic oligoalkyltrichlorosiloxanes (RClSiO)m (m = 3-6).

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]mSiCl2R (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]mOSiMe3 (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.

Generation and capture of methyl(vinyl)silanone

Methyl(vinyl)dichlorosilane reacts with DMSO in the presence of hexamethyldisiloxane to give the corresponding linear oligosiloxanes of the general formula Me3Si(OSiMeVin)nOSiMe3 (n=1–6) as well as MeSi(OSiMe3)3 and Me3Si(MeOSiVin)mOSi(OSiMe3)(Me)OSiMe3 (m=1–2). The same reaction in the presence of chlorotrimethylsilane results in oligomers of the general formula Me3Si(OSiMeVin)nCl (n=1–3). A possible scheme of their formation is discussed.

Unusual transformations of difluorosilanone F2Si=O

The structure and properties of fluorosilicon polymer (fluorosil) formed by the reaction of phenyltrifluorosilane with aliphatic alcohols have been studied by the methods of IR, 19F, 29Si NMR spectroscopy, high temperature mass-spectrometry, derivatography and atom emission analysis. Due to its high reactivity, this polymer readily reacts with glass of the reaction vessel extracting the ions of all metals entering into its composition. Fluorosil formed in a quartz, teflon or polypropylene reactors is characterized by low stability and is slowly decomposed to SiF4 and SiO2. Apparently, fluorosil is the product of incorporation of SiF4 into the SiO2 matrix.

New method of tris(trimethylsilyl) antimonite preparation

Tris(trimethylsilyl) antimonite, (Me3SiO)3Sb was for the first time prepared by the reaction of trimethylsilanol with triethyl antimonite in 67% yield [1]. But the strong tendency of trimethylsilanol to take part in anhydrocondensation resulting in the formation of hexamethyldisiloxane decreased the preparative value of this method. The attempts to prepare tris (trimethylsilyl) antimonite by the reaction of sodium trimethylsilanolate with the antimony trichloride [2] or trimethylsilanol with the antimony triacetate [3] failed. Later tris(trihydrocarbylsilyl) antimonites attracted the attention of many researchers [4–6] and were used as precursors of the antimony silicate glass for coatings in microelectronics [7].

Reaction of arylarsonic acids with organylalkoxy- and organylacetoxy-silanes

ConclusionsThe reaction of phenylarsonic acid with trialkylalkoxy- or trialkylacetoxysilanes leads to the formation of bis(trialkylsilyl)phenylarsonates. Bis(trimethylsilyl)- and bis(dimethylsilyDphenylarsonates are thermally unstable and decompose upon separation.2. The reaction of phenylarsonic acid with organylalkoxy- or tetraalkoxysilanes is a convenient method for the preparation of dialkylphenylarsonates.