26980-42-7Relevant academic research and scientific papers
Synthesis of Functional Monosilanes by Disilane Cleavage with Phosphonium Chlorides
Santowski, Tobias,Sturm, Alexander G.,Lewis, Kenrick M.,Felder, Thorsten,Holthausen, Max C.,Auner, Norbert
supporting information, p. 3809 - 3815 (2019/02/13)
The Müller–Rochow direct process (DP) for the large-scale production of methylchlorosilanes MenSiCl4?n (n=1–3) generates a disilane residue (MenSi2Cl6?n, n=1–6, DPR) in thousands of tons annually. This report is on methylchlorodisilane cleavage reactions with use of phosphonium chlorides as the cleavage catalysts and reaction partners to preferably obtain bifunctional monosilanes MexSiHyClz (x=2, y=z=1; x,y=1, z=2; x=z=1, y=2). Product formation is controlled by the reaction temperature, the amount of phosphonium chloride employed, the choice of substituents at the phosphorus atom, and optionally by the presence of hydrogen chloride, dissolved in ethers, in the reaction mixture. Replacement of chloro by hydrido substituents at the disilane backbone strongly increases the overall efficiency of disilane cleavage, which allows nearly quantitative silane monomer formation under comparably moderate conditions. This efficient workup of the DPR thus not only increases the economic value of the DP, but also minimizes environmental pollution.
Interactions of chloromethyldisilanes with tetrakis(dimethylamino)ethylene (TDAE), formation of [TDAE] [Si3Me2Cl7]
Knopf,Herzog,Roewer,Brendler,Rheinwald,Lang
, p. 14 - 22 (2007/10/03)
The chlorodisilanes SiClMe2-SiClMe2 (1), SiCl2Me-SiCl2Me (2), SiCl3-SiCl3 (3) and a 9:1 mixture of 2 and SiCl3-SiCl2Me (4) were reacted with the electron-rich alkene tetrakis-(dimethylamino)-ethylene (TDAE) in n-hexane as well as in polar solvents. While 1 gave no reaction at all, 3 underwent a disproportionation reaction into SiCl4 and Si(SiCl3)4. Also 2 and mixtures of 2 and 4 were disproportionated into MeSiCl3 (2a) and methylchlorooligosilanes. Additionally a crystalline mixture of Si3Me3Cl6 -TDAE (5a) plus Si3Me2Cl7 -TDAE (5b) was obtained by reaction of a 9:1 mixture of 2 and 4 with TDAE in n-hexane as well as in 1,2-dimethoxyethane. The reaction of 2 with TDAE in acetonitrile (MeCN) led to a crystalline precipitation of [TDAE]Cl2 -MeCN (6.MeCN) in addition to MeSiCl3 and methylchlorooligosilanes. The structures of 5b and 6.MeCN were determined by X-ray crystallography beside their NMR and IR spectroscopic characterization. Compound 5b crystallizes in the monoclinic space group P2/c (Z = 4), 6.MeCN in the orthorhombic space group Pna21 (Z = 4). The structure of 5b reveals a [TDAE].+ radical cation and a 1, 2-Me2Si3Cl7- anion with a pentacoordinated central silicon atom.
Methylchlorooligosilanes as products of the basecatalysed disproportionation of various methylchlorodisilanes
Herzog,Richter,Brendler,Roewer
, p. 221 - 228 (2007/10/03)
The methylchlorodisilanes SiCl2Me-SiCl2Me (1), SiCl2Me-SiClMe2 (2) and SiClMe2-SiClMe2 (3) disproportionate in the presence of a basic catalyst into methylchloromonosilanes and various methylchlorooligosilanes. Oligosilanes involving up to seven silicon atoms were identified by means of 29Si-, 13C-1H-NMR and GC-MS measurements. Formation of methylchlorooligosilanes is thought to take place via silylene intermediates.
