- SYNTHESIS OF ORGANO CHLOROSILANES FROM ORGANOSILANES
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The invention relates to a process for the production of chlorosilanes by subjecting one or more hydndosilanes to the reaction with hydrogen chloride in the presence of at least one ether compound, and a process for the production of such hydndosilanes serving as starting materials.
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Page/Page column 36; 37
(2019/04/16)
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- Synthesis of Polycyclic and Cage Siloxanes by Hydrolysis and Intramolecular Condensation of Alkoxysilylated Cyclosiloxanes
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The controlled synthesis of oligosiloxanes with well-defined structures is important for the bottom-up design of siloxane-based nanomaterials. This work reports the synthesis of various polycyclic and cage siloxanes by the hydrolysis and intramolecular condensation of monocyclic tetra- and hexasiloxanes functionalized with various alkoxysilyl groups. An investigation of monoalkoxysilylated cyclosiloxanes revealed that intramolecular condensation occurred preferentially between adjacent alkoxysilyl groups to form new tetrasiloxane rings. The study of dialkoxy- and trialkoxysilylated cyclotetrasiloxanes revealed multistep intramolecular condensation reactions to form cubic octasiloxanes in relatively high yields. Unlike conventional methods starting from organosilane monomers, intramolecular condensation enables the introduction of different organic substituents in controlled arrangements. So-called Janus cubes have been successfully obtained, that is, Ph4R4Si8O12, in which R=Me, OSiMe3, and OSiMe2Vi (Vi=vinyl). These findings will enable the creation of siloxane-based materials with diverse functions.
- Sugiyama, Tomoaki,Shiba, Hiroya,Yoshikawa, Masashi,Wada, Hiroaki,Shimojima, Atsushi,Kuroda, Kazuyuki
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p. 2764 - 2772
(2019/02/01)
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- Lewis Base Catalyzed Selective Chlorination of Monosilanes
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A preparatively facile, highly selective synthesis of bifunctional monosilanes R2SiHCl, RSiHCl2 and RSiH2Cl is reported. By chlorination of R2SiH2 and RSiH3 with concentrated HCl/ether solutions, the stepwise introduction of Si?Cl bonds is readily controlled by temperature and reaction time for a broad range of substrates. In a combined experimental and computational study, we establish a new mode of Si?H bond activation assisted by Lewis bases such as ethers, amines, phosphines, and chloride ions. Elucidation of the underlying reaction mechanisms shows that alcohol assistance through hydrogen-bond networks is equally efficient and selective. Remarkably, formation of alkoxysilanes or siloxanes is not observed under moderate reaction conditions.
- Sturm, Alexander G.,Schweizer, Julia I.,Meyer, Lioba,Santowski, Tobias,Auner, Norbert,Holthausen, Max C.
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supporting information
p. 17796 - 17801
(2018/11/23)
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- B(C6F5)3-Catalyzed Selective Chlorination of Hydrosilanes
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The chlorination of Si?H bonds often requires stoichiometric amounts of metal salts in conjunction with hazardous reagents, such as tin chlorides, Cl2, and CCl4. The catalytic chlorination of silanes often involves the use of expensive transition-metal catalysts. By a new simple, selective, and highly efficient catalytic metal-free method for the chlorination of Si?H bonds, mono-, di-, and trihydrosilanes were selectively chlorinated in the presence of a catalytic amount of B(C6F5)3 or Et2O?B(C6F5)3 and HCl with the release of H2 as a by-product. The hydrides in di- and trihydrosilanes could be selectively chlorinated by HCl in a stepwise manner when Et2O?B(C6F5)3 was used as the catalyst. A mechanism is proposed for these catalytic chlorination reactions on the basis of competition experiments and density functional theory (DFT) calculations.
- Chulsky, Karina,Dobrovetsky, Roman
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supporting information
p. 4744 - 4748
(2017/04/11)
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- PROCESS FOR THE PREPARATION OF HALOALKYLALKOXYSILANCS AND HALOALKYLHALOSILANES
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This invention involves a process for the preparation of haloalkylalkoxysilanes and haloalkylhalosilancs. The process comprises reacting an alkoxyhydridosilane or a halohydridosilanc silane with an alkenylhalide compound in the presence of a catalytic amount of an iridium containing catalyst. When a halohydridosilane is the silane rcactant. the resulting haloalkylhalosilane may be alkoxylatcd by reaction with a C1-C6, alcohol, In another aspect of the invention, the reacting is conducted under a reduced oκygen atmosphere to improve the catalyst activity and the yield of the resulting haloalkylhalosilane or halυalkylalkυx vsi lane.
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Page/Page column 12-13
(2009/10/22)
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- Process for making haloalkylalkoxysilanes
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A haloalkylalkoxysilane is prepared by reacting an olefinic halide with an alkoxysilane in which the alkoxy group(s) contain at least two carbon atoms in the presence of a catalytically effective amount of ruthenium-containing catalyst. The process can be used to prepare, inter alia, chloropropyltriethoxysilane which is a key intermediate in the manufacture of silane coupling agents.
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- Reaction of Tetraalkoxysilanes with Alkyl(aryl)chlorosilanes
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Alkyl(aryl)trichloro- or dialkyl(diaryl)dichlorosilanes react with tetraalkoxysilanes Si(OMe)4, Si(OEt)4, and Si(OBu)4 to give partially etherfied alkyl(aryl)chlorosilanes RSiCl2(OAlk), RSiCl(OAlk)2, and R2SiCl(OAlk).
- Chernyshev, E. A.,Komalenkova, N. G.,Tagachenkov, A. A.,Bykovchenko, V. G.
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p. 241 - 243
(2007/10/03)
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