556-67-2Relevant articles and documents
Silylating Disulfides and Thiols with Hydrosilicones Catalyzed by B(C6F5)3
Brook, Michael A.,Liao, Mengchen,Zheng, Sijia
supporting information, p. 2694 - 2700 (2021/06/25)
Hydrosilanes and silicones, catalyzed with B(C6F5)3, may be used to silylate thiols or cleave disulfides giving silyl thio ethers. Alcohols were found to react faster than thiols or disulfides, while alkoxysilanes (the Piers-Rubinsztajn reaction) were slower such that the overall order of reactivity was found to be HO>HS>SS>SiOEt. The resulting silane and silicone-protected thio ethers produced from the sulfur-based functional groups could be cleaved to thiols using alcohols or mild acid with rates that depend on the steric bulk of the siloxane.
Hydrogenolysis of Polysilanes Catalyzed by Low-Valent Nickel Complexes
Comas-Vives, Aleix,Eiler, Frederik,Grützmacher, Hansj?rg,Pribanic, Bruno,Trincado, Monica,Vogt, Matthias
supporting information, p. 15603 - 15609 (2020/04/29)
The dehydrogenation of organosilanes (RxSiH4?x) under the formation of Si?Si bonds is an intensively investigated process leading to oligo- or polysilanes. The reverse reaction is little studied. To date, the hydrogenolysis of Si?Si bonds requires very harsh conditions and is very unselective, leading to multiple side products. Herein, we describe a new catalytic hydrogenation of oligo- and polysilanes that is highly selective and proceeds under mild conditions. New low-valent nickel hydride complexes are used as catalysts and secondary silanes, RR′SiH2, are obtained as products in high purity.
Heterocyclization and solvent interception upon oxidative triflamidation of allyl ethers, amines and silanes
Ganin, Anton S.,Moskalik, Mikhail Yu.,Astakhova, Vera V.,Sterkhova, Irina V.,Shainyan, Bagrat A.
, (2020/07/20)
The reactions of triflamide with a series of mono- and diallyl heteroatomic compounds have been studied in the presence of various oxidants (t-BuOI, NBS, NIS). The reaction course was found to be strongly dependent on the oxidant leading to the products of bis(triflamidation) or heterocyclization in the system (t-BuOCl + NaI), or amidines – the Ritter-type solvent interception halosulfamidation products – with N-bromo- or N-iodosuccinimide. The amidines were converted to imidazolines in high yield via the base-induced heterocyclization.
METHOD FOR PRODUCING SILOXANE OLIGOMER
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Paragraph 0034; 0045, (2017/07/23)
PROBLEM TO BE SOLVED: To provide a production method capable of simply producing a siloxane oligomer in a high yield when producing a siloxane oligomer by hydrolysis of a silicon halide compound and to provide a production method capable of selectively producing a linear or cyclic siloxane oligomer in particular. SOLUTION: The siloxane oligomer can be efficiently produced without performing any special agitation by providing two electrospray nozzles to oppose to each other in a medium liquid and in the medium liquid, electrostatically spraying in an electric field a first liquid sample containing a silicon halide compound from one nozzle and electrostatically spraying in an electric field a second liquid sample containing water from the other nozzle and allowing the liquid samples to collide and fuse with each other. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
Tris(pentafluorophenyl)borane-Catalyzed Reactions of Siloxanes: A Combined Experimental and Computational Study
Mathew, Jomon,Eguchi, Katsuya,Nakajima, Yumiko,Sato, Kazuhiko,Shimada, Shigeru,Choe, Yoong-Kee
, p. 4922 - 4927 (2017/09/13)
The reaction of 1,1,3,3-tetramethyldisiloxane with 1-octene as a model reaction of silicone curing catalyzed by B(C6F5)3 resulted in the redistribution of the disiloxane into dimethylsilane and cyclic oligosiloxanes, and the subsequent hydrosilylation reaction of dimethylsilane afforded dimethyldioctylsilane. To obtain insights into the reaction mechanism and possibility alter the reaction pathway to favor the hydrosilylation over the redistribution, mechanistic analysis of the reaction between a hydrosiloxane (1,1,3,3-tetramethyldisiloxane, silox-H) and a vinylsiloxane (1,1,3,3-tetramethyl-1,3-divinyldisiloxane, silox-vin) in the presence of B(C6F5)3 was performed through density functional theory calculations. The results of the calculations indicate that the activation of a Si–H bond in silox-H by B(C6F5)3 initiates the reaction to form the B(C6F5)3–silox-H complex with a Lewis acidic silicon atom and a hydridic hydrogen atom. The B(C6F5)3–silox-H complex can undergo two different reaction pathways, that is, trisiloxane formation and the hydrosilylation of silox-vin by silox-H. The trisiloxane formation involves trisilyloxonium ions as intermediates and can lead to either the homotrisiloxane of silox-H or a mixed trisiloxane of silox-H and silox-vin. The energetics of the reaction pathways predict the preference of trisiloxane formation over hydrosilylation, and the fine tuning of the steric and electronic natures of the substrates could alter the thermodynamic and kinetic favorability.
A dimethyl dichloro silane hydrolysate cracking method
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Paragraph 0026; 0028, (2017/02/24)
The invention discloses a method for splitting dimethyl dichlorosilane hydrolysate. The method comprises the following steps: carrying out load reaction onto strong-basicity macroporous anion exchange resin, potassium hydroxide, potassium trimethylsilanolate and [bmim]BF4 ionic liquid to obtain a composite catalyst after the reaction is ended; adding dimethyl dichlorosilane hydrolysate into a splitting kettle to obtain a ring-body mixture by splitting and re-arranging solvent oil, the composite catalyst and the hydrolysate; and washing with water to remove high-boiling point residues and low-boiling point residues to obtain products such as octamethylcyclotetrasiloxane D4, hexamethylcyclotrisiloxane and decamethylcyclopentasiloxane.
Selective Formation of Alkoxychlorosilanes and Organotrialkoxysilane with Four Different Substituents by Intermolecular Exchange Reaction
Komata, Yuma,Yoshikawa, Masashi,Tamura, Yasuhiro,Wada, Hiroaki,Shimojima, Atsushi,Kuroda, Kazuyuki
, p. 3225 - 3233 (2016/11/29)
Alkoxychlorosilanes are scientifically and industrially important toward preparing silicone and silica as well as preparation of siloxane-based nanomaterials by stepwise reactions of Si?OR (R=alkyl) and Si?Cl groups. Intermolecular exchange of alkoxy and chloro groups between alkoxysilanes and chlorosilanes (functional group exchange reaction) provides an efficient and environmentally benign route to alkoxychlorosilanes. BiCl3 as a Lewis acid catalyst can promote the functional group exchange reactions more efficiently than conventional acid catalysts. Higher reactivity has been observed for chlorosilanes with smaller numbers of Si?CH3 groups and for alkoxysilanes with larger numbers of Si?CH3 groups. The reaction mechanism is proposed and selective syntheses of alkoxychlorosilanes are demonstrated. These findings also enable us to synthesize an organotrialkoxysilane with four different substituents.
One-Step Synthesis of Siloxanes from the Direct Process Disilane Residue
Neumeyer, Felix,Auner, Norbert
supporting information, p. 17165 - 17168 (2016/11/23)
The well-established Müller–Rochow Direct Process for the chloromethylsilane synthesis produces a disilane residue (DPR) consisting of compounds MenSi2Cl6?n(n=1–6) in thousands of tons annually. Technologically, much effort is made to retransfer the disilanes into monosilanes suitable for introduction into the siloxane production chain for increase in economic value. Here, we report on a single step reaction to directly form cyclic, linear, and cage-like siloxanes upon treatment of the DPR with a 5 m HCl in Et2O solution at about 120 °C for 60 h. For simplification of the Si?Si bond cleavage and aiming on product selectivity the grade of methylation at the silicon backbone is increased to n≥4. Moreover, the HCl/Et2O reagent is also suitable to produce siloxanes from the corresponding monosilanes under comparable conditions.
Depolymerization of end-of-life poly(dimethylsilazane) with boron trifluoride diethyl etherate to produce difluorodimethylsilane as useful commodity
D?hlert, Peter,Pfrommer, Johannes,Enthaler, Stephan
, p. 1189 - 1193 (2016/08/31)
A straightforward protocol for the depolymerization of end-of-life poly(dimethylsilazane) using boron trifluoride diethyl etherate as depolymerization reagent to convert the Si-N to Si-F bonds was set-up. The application of the depolymerization reagent affords difluorodimethylsilane as major products, which can be a suitable synthon for the synthesis of new polymers (e.g., poly(dimethylsiloxanes) and allow an overall recycling of the [Me2Si]-unit.
Method for preparing hybrid cyclo-boron siloxane
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Paragraph 0032; 0033; 0034; 0035; 0036; 0037; 0038, (2016/10/10)
The invention relates to the field of chemistry and chemical engineering, provides a cheap and efficient cyclo-boron siloxane intermediate in order to prepare high-performance boracic polysiloxane, and particularly provides a method for preparing hybrid cyclo-boron siloxane. Under inert gas shielding, a mixture of alkyl boric acid and an organic solvent A is dropwise added to dialkyl dichloro-slane, stirring and reacting are carried out for 3 h to 8 h at the temperature of -20 DEG C to 80 DEG C, then the mixture is added into a mixture of an organic solvent B and metallic oxide, filtering and washing are carried out after reacting is carried out for 6 h to 18 h, the organic solvent A and the organic solvent B are evaporated out, and hybrid cyclo-boron siloxane is obtained. The method has the advantages that the raw materials can be obtained easily, and cost is low, and the compound can be used for synthesizing boron-silicon rubber, a heat-resisting adhesive, a heat-resisting coating and other boracic polysiloxane products, and can be widely applied to aerospace, electronics, chemical engineering, machinery and other industries.
