- Process for the manufacture of hydrogen-rich cyclosiloxane
-
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.
- -
-
Page/Page column 6
(2010/02/17)
-
- Linear polysiloxanes from dichlorosilane
-
Polysiloxanes of type RR′R″SiO(SiH2O)nSiRR′R″ (R, R′, R″ = Me, Me, Me; Me, H, H; Et, Et, Et; Me, Me, H) have been prepared by three different methods: (1) reactions of ClSiH2O(SiH2O)nSiH2Cl with CH3MgBr, Me3SiOH, and Et3SiOH; (2) H2SO4-catalyzed equilibration of cyclic [H2SiO]n oligomers with Me3SiOSiMe3; (3) cohydrolysis of H2SiCl2 with Me3SiCl and Me2HSiCl using NaH2PO4/Na2HPO4-buffered media. Lower species, Me2RSiO(SiH2O)nSiMe2R (n = 1-3), were isolated and characterized (R = Me, H).
- Seyferth, Dietmar,Prud'homme, Christian C.
-
p. 4412 - 4417
(2008/10/08)
-
- Cyclic polysiloxanes from the hydrolysis of dichlorosilane
-
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.
- Seyferth, Dietmar,Prud'homme, Christian,Wiseman, Gary H.
-
p. 2163 - 2167
(2008/10/08)
-