- PROCESSES FOR SYNTHESIZING UNSYMMETRICAL DISILOXANES
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Described herein are methods for making alkenyl disiloxanes, comprising combining an alkenyl halosilane with an alkyl halosilane and adding the mixture to water, an acidic aqueous solution, or a basic aqueous solution. The ratio of the alkenyl halosilane to the alkyl halosilane is about 10:1 to about 1:10. The alkenyl halosilane and the alkyl halosilane are mixed at about 20 °C to about 45 °C. The reaction product is separated and washed with saturated alkali carbonate solution.
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Paragraph 0044-0046
(2021/06/22)
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- Low alkoxy branched siloxane continuous number bath method
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The subject matter of the invention is a continuous method for producing organosiloxanes (O) by reacting silicon compound 1 of general formula 1 RnSiHal4_n (1) and silicon compound 2 which is selected from a silicon compound of general formula 2a or a silicon compound of general formula 2b or mixtures of the silicon compounds of general formulas 2a and 2b R1 3SiHal (2a), R1 3Si-O-SiR1 3 (2b), where R, R1, Hal and n have the meanings described in claim 1, with alcohol and water in the presence of organosiloxane (O) in a reaction unit comprising a distillation column and a vessel (G) which is arranged therebeneath and contains organosiloxane (O), wherein: the content of the vessel is heated to boiling with reflux; silicon compound 1 is introduced into the column above the lower column end; silicon compound 2 is introduced into the vessel (G); the hydrogen halide produced is removed by means of the distillation column; and organosiloxane (O) is continuously withdrawn from the vessel as it is formed, wherein the reaction unit is constantly supplied with silicon compound 1, silicon compound 2, alcohol and water in such quantities that the reaction unit always contains more water than can be consumed by the silicon compound 1 and silicon compound 2 added.
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Paragraph 0158-0169
(2019/05/15)
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- Preparation method of 1-vinyl-1,1,3,3,3-pentamethyldisiloxane
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The invention relates to a preparation method of 1-vinyl-1,1,3,3,3-pentamethyldisiloxane, prepared by: using 1,3-divinyl-1,1,3,3,-tetramethyldisiloxane ad 1,1,1,3,3,3-hexamethyldisiloxane as materials, carrying out rearrangement reaction under the catalytic action of a complexing catalyst KOH/18-crown ether-6; neutralizing the catalyst, filtering, and distilling filtrate. The macromolecular ring compound 18-crown ether-6 and KOH form the complexing agent; the compound reaction helps improve catalyst activity and efficiently catalyzes for rearrangement reaction. The macromolecular ring compound18-crown ether-6 and KOH form a complexing catalyst; complexing reaction is performed to obtain improved catalyst activity, and rearranging reaction is efficiently catalyzed. In addition, the preparation method is simple, the reacting is fast and stable, and the preparation method has the advantages of high yield, good safety, good environmental friendliness and the like.
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Paragraph 0039-0041
(2018/09/11)
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- Method for preparing 1,3-divinyl-1,1,3,3-tetramethyldisiloxane
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The invention discloses a method for preparing 1,3-divinyl-1,1,3,3-tetramethyldisiloxane. The method comprises the following step: 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is prepared from 1,1,3,3-tetramethyldisiloxane, acetylene, cocatalyst amine compounds and a reaction system formed by a catalyst ruthenium compound through reaction. According to the preparation method, 1,1,3,3-tetramethyldisiloxane and acetylene can be subjected to reaction in one step under the mild condition for generation of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane. The method has the advantages of few side reactions,high yield of main products, lower cost and high safety, and is suitable for industrial production.
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Paragraph 0014; 0015; 0016-0019; 0020-0023; 0024-0027
(2018/06/26)
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- NHO to aNHC Isomerization at a Pd0-Center
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N-heterocyclic carbenes (NHCs) are a highly important class of ligands in transition metal-mediated catalysis. Recently, a modification of the NHCs has received considerable interest, the N-heterocyclic olefins (NHOs) with an exocyclic methylene appended to the NHC. In here we investigated the propensity of NHOs to act as a ligands for Pd0 complexes derived from [Pd2(dvds)3]. The reaction of IPrCH2 and IMesCH2 with the Pd0 precursor [Pd2(dvds)3] resulted in the formation of abnormal N-heterocyclic carbene complexes [(aIPrCH3)Pd(dvds)] (1) and [(aIMesCH3)Pd(dvds)] (2). DFT calculations were applied to study this isomerization and to reveal the bonding in 1 and 2. In addition, the backbone-methylated NHOs MeIPrCH2 and mMeIMesCH2 (4) were shown not to undergo the isomerization observed in IPrCH2 and IMesCH2.
- Schumann, André,Hering-Junghans, Christian
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p. 2584 - 2588
(2018/06/04)
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- An efficient catalytic approach for the synthesis of unsymmetrical siloxanes
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The potential for expanding the variety of catalytic methods for siloxane bond formation is explored. Alkoxysilanes react with methylallylsilanes in the presence of scandium(III) trifluoromethanesulfonate to yield disiloxanes and isobutene. The reaction p
- Hreczycho, Grzegorz
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- Mechanistic studies on the Pd-catalyzed vinylation of aryl halides with vinylalkoxysilanes in water: The effect of the solvent and NaOH promoter
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The mechanism of the Pd-catalyzed vinylation of aryl halides with vinylalkoxysilanes in water has been studied using different catalytic precursors. The NaOH promoter converts the initial vinylalkoxysilane into a highly reactive water-soluble vinylsilanolate species. Similarly, deuterium-labeling experiments have shown that, irrespective of the catalytic precursor used, vinylation occurs exclusively at the CH vinylic functionality via a Heck reaction and not at the C-Si bond via a Hiyama cross-coupling. The involvement of a Heck mechanism is interpreted in terms of the reduced nucleophilicity of the base in water, which disfavors the transmetalation step. The Heck product (β-silylvinylarene) undergoes partial desilylation, with formation of a vinylarene, by three different routes: (a) hydrolytic desilylation by the aqueous solvent (only at high temperature); (b) transmetalation of the silyl olefin on the PdH Heck intermediate followed by reductive elimination of vinylarene; (c) reinsertion of the silyl olefin into the PdH bond of the Heck intermediate followed by β-Si syn-elimination. Both the Hiyama and Heck catalytic cycles and desilylation mechanisms b and c have been computationally evaluated for the [Pd(en)Cl2] precursor in water as solvent. The calculated Gibbs energy barriers support the reinsertion route proposed on the basis of the experimental results.
- Gordillo, Alvaro,Ortuno, Manuel A.,Lopez-Mardomingo, Carmen,Lledos, Agusti,Ujaque, Gregori,De Jesus, Ernesto
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supporting information
p. 13749 - 13763
(2013/10/01)
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- VOLATILE LIQUID COPPER PRECURSORS FOR THIN FILM APPLICATIONS
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The present invention provides copper +1 compounds for film depositon of copper that retain the low tempertaure processing advantages typical for copper +1 compounds, but which have the thermal stability normally associated with copper +2 compounds. Such compounds are suitable for use as copper precursors for the growth of thin copper films for various applications by Chemical Vapor Deposition (CVD) or Atomic Layer Deposition (ALD).
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Page/Page column 14-15
(2008/12/07)
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- Reaction of 1-hydrohexafluoroisobutenyloxytrimethylsilane with fluoride ion sources. 2,2,2′,2′-Tetrakis(trifluoromethyl)divinyl ether
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The reaction of 1-hydrohexafluoroisobutenyloxytrimethylsilane (2a) with cesium fluoride in diglyme leads to elimination of trimethylfluorosilane to form the 1-hydrohexafluoroisobutenolate anion (3), which is silylated with trialkylchlorosilanes at the oxygen atom. In the presence of bis(trifluoromethyl)ketene N,N,O-trimethylaminoacetal or N-(α,α- difluoroalkyl)-dialkylamines, silane 2a is transformed into 2,2,2′, 2′-tetrakis(trifluoromethyl)divinyl ether. The reaction of trifluoroacetic anhydride with N-(1,1,2,2-tetrafluoroethyl)diethylamine affords trifluoroacetyl fluoride in quantitative yield.
- Volkonskii,Kagramanova,Mysov,Mysova
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p. 2774 - 2781
(2007/10/03)
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- Studies of silyl and germyl Group VI species. Part VII. The substituent effects of the vinyl group in 1,3-divinyltetramethyldisilyl chalcogenides
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Symmetrically substituted 1,3-divinyltetramethyldisilyl chalcogenides (CH2=CHSiMe2)2E, where E = O, S, Se, and Te have been prepared and characterized by their ir, Raman, (1)H and (13)C nmr spectra.Reactions of the sulfide and selenide with anhydrous H2S and H2Se, respectively, are discussed.
- Drake, John E.,Vahradian, Ankin,Glavincevski, Boris M.
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p. 2712 - 2715
(2007/10/02)
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