1873-88-7Relevant articles and documents
Synthesis of methyl(1-aminophosphonate)siloxane oligomers
Khairova,Milenin,Cherkaev,Stoikov,Muzafarov
, p. 1285 - 1288 (2017/02/05)
A synthesis of 1-aminophosphonate derivative of methylsiloxane oligomer was developed. A methodology of the introduction of 1-aminophosphonate fragment not only into the stable siloxane structures, but also into hydrolytically unstable alkoxyfunctional organosilicon compounds was suggested.
Method for preparing 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane
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Paragraph 0009; 0010, (2016/11/17)
The invention discloses a method for preparing 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane. According to the method, concentrated sulfuric acid with the mass concentration being 98% serves as a catalyst, methyl hydrogen silicone oil 202 and hexamethyldisiloxane serve as raw materials, a catalyst reaction is conducted, and the 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane with the mass concentration being 99% and above is obtained. According to the method, the concentrated sulfuric acid serves as the catalyst, the catalyst is simple and easy to obtain, the price is low, the catalysis effect is good, operation is convenient and fast, production cost is lowered, and production efficiency is effectively improved.
Hydrosilation of endo-cis-5-Norbornene-2,3-dicarboxylic Anhydride
Trofimov,Skvortsov,Pashnova,Skvortsov
, p. 572 - 577 (2007/10/03)
In hydrosilation of endo-cis-5-norbornene-2,3-dicarboxyIic anhydride with pentamethyldisiloxane and heptamethyltrisiloxane catalyzed by platinum(II) complexes, the mixed complexes with amino and sulfoxide ligands are the most active. The differences between the activities of the exo and endo isomers were explained on the basis of quantum chemical calculations indicating significant difference in the frontal orbitals of the exo and endo derivatives of norbornenedicarboxylic anhydride and the corresponding imides. A lower activity of the endo isomers is due to a change in the structure of the lowest unoccupied molecular orbital and its weak π-acceptor interaction with the transition metal atom in the course of the catalytic cycle.
Kinetic Investigation of the Platinum-catalysed Hydrosilylation of Vinylsiloxanes with Hydrogensiloxanes
Brand, Dagmar,Moretto, Hans-Heinrich,Schulze, Manfred,Wrobel, Dieter
, p. 218 - 224 (2007/10/02)
A kinetic investigation of the platinum-catalysed hydrosilylation of monofunctional oligomeric vinylsiloxanes by monofunctional oligomeric hydrogensiloxanes was performed under stoichiometric conditions with use of quantitative 1H-NMR spectrometry.The reaction rate up to 50percent conversion can be expressed by v=k .During further hydrosilylation the kinetic changed to second order.No induction period was observed.A hydrogensiloxane with a dimethylsilyl end group gives much higher rates than a siloxane with a methylsiloxy group.The main reactions of all hydrosilylations, determined by GC-MS and 29Si-NMR, are β-additions.Less then 5percent α-products are obtained.
FEATURES OF INFLUENCE OF HCl ON HYDROLYTIC COPOLYCONDENSATION OF BIFUNCTIONAL ORGANOCHLOROSILANES WITH TRIMETHYLCHLOROSILANE
Kopylov, V. M.,Agashkov, S. P.,Sunkovich, G. V.,Prikhod'ko, P. L.
, p. 1257 - 1261 (2007/10/02)
The hydrogen chloride that is formed in the hydrolytic copolycondensation of R'RSiCl2 with Me3SiCl affects the composition of the reaction products only at cocentrations above 30-35percent, where it is responsible for splitting out the terminal trimethylsiloxy group.The stability of the terminal groups increases with increasing size of the substituents on the silicon atom in the R'RSiCl2.The total yield of Me3SiO(R'RSiO)mSiMe3 with m = 1-4 also increases with increasing size of the substituents on the silicon atom in the R'RSiCl2.The total yield of p with p = 3-5 increases with decreasing tendency of the R'RSiCl2 to form rings by hydrolytic polycondensation, and with increasing sensitivity of the terminal trimethylsiloxy group in the cocondensation products to the action of HCl and its activity with respect to the siloxane bond.
METAL COMPLEX-CATALYZED REDISTRIBUTION REACTIONS OF ORGANOSILANES. IV. REDISTRIBUTION REACTIONS OF METHYLSILOXANES CATALYZED BY TRANSITION METAL COMPLEXES
Gustavson, Wayne A.,Epstein, Paul S.,Curtis, M.D.
, p. 87 - 98 (2007/10/02)
Redistribution reactions of a variety of hydrogen-substituted siloxanes are catalyzed by various transition metal complexes of iridium and rhodium.The products arise from breaking and remaking of Si-C, Si-H, and Si-O bonds.Siloxanes not possessing a Si-H bond are inert under the conditions studied.The most favored reaction pathway appears to scramble preferentially the groups directly attached to the silicon bearing the hydrogen atom.A new cyclo-iridiadisiloxane, (L = Ph3P; R = Me3SiO) is reported.This compound exists in three isomeric forms as a consequence of the spatial arrangements of the R and Me groups on the ring.
