293-51-6Relevant articles and documents
Process for the manufacture of hydrogen-rich cyclosiloxane
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Page/Page column 6, (2010/02/17)
The present invention relates to a for controlled synthesis of hydrogen-rich cyclosiloxanes of the (H2SiO)n type. where n is an integer equal to or greater than 3, by reacting: a.) a halosilane of the H2SiX2 type where X=halogen withb.) a lithium salt, copper(II) salt or a salt of a metal from main group 2 or transition group 2 of the periodic table of the elements, or a mixture of these salts. The ring size is advantageously adjustable to n=3, 4, 5, 6 (especially n=4 to 6), such that larger rings are not formed. In a particularly advantageous embodiment of the process, for the selective preparation of cyclohexasiloxane (H2SiO)6, after the reaction, the solvent is at least partly removed and then solvent is added again.
Cyclic polysiloxanes from the hydrolysis of dichlorosilane
Seyferth, Dietmar,Prud'homme, Christian,Wiseman, Gary H.
, p. 2163 - 2167 (2008/10/08)
The hydrolysis of H2SiCl2 in dichloromethane solution, either with a stoichiometric amount of water at -30 to -20°C or by slow, controlled addition of a slight excess of water at 0°C, results in the formation of siloxanes of type [H2SiO]n. In the volatile fraction oligomers with n from 4 up to 23 were found. Those with n = 4-6 were isolated by GC and characterized (1H and 29Si NMR, IR, n25D, mass spectroscopy). A brief study was made of the hydrolysis of MeSiHCl2 and Me2SiCl2 under comparable conditions.
