- Protecting and Leaving Functions of Trimethylsilyl Groups in Trimethylsilylated Silicates for the Synthesis of Alkoxysiloxane Oligomers
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The concept of protecting groups and leaving groups in organic synthesis was applied to the synthesis of siloxane-based molecules. Alkoxy-functionalized siloxane oligomers composed of SiO4, RSiO3, or R2SiO2 units were chosen as targets (R: functional groups, such as Me and Ph). Herein we describe a novel synthesis of alkoxysiloxane oligomers based on the substitution reaction of trimethylsilyl (TMS) groups with alkoxysilyl groups. Oligosiloxanes possessing TMS groups were reacted with alkoxychlorosilane in the presence of BiCl3 as a catalyst. TMS groups were substituted with alkoxysilyl groups, leading to the synthesis of alkoxysiloxane oligomers. Siloxane oligomers composed of RSiO3 and R2SiO2 units were synthesized more efficiently than those composed of SiO4 units, suggesting that the steric hindrance around the TMS groups of the oligosiloxanes makes a difference in the degree of substitution. This reaction uses TMS groups as both protecting and leaving groups for SiOH/SiO? groups.
- Yoshikawa, Masashi,Tamura, Yasuhiro,Wakabayashi, Ryutaro,Tamai, Misa,Shimojima, Atsushi,Kuroda, Kazuyuki
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- Some regularities of chlorosilanes etherification
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The influence of reagents, solvent polarity, and temperature on the etherification of chlorosilanes ClCH2SiCl3, VinSiCl 3, PrSiCl3, and Ph3SiCl with ethanol was studied. Influence of reaction temperature on the ratio of the synthesized alkoxysilane and related side-product siloxane is revealed. Use of excess alcohol is shown to increase the content of siloxane. Introduction of FeCl 3 does not affect the synthesis. Solvents are shown to influence the reaction rate: the rate constant increases with increasing ε parameter of the solvent. The rate constant of etherification of chlorosilanes with ethanol falls in the series: ClCH2SiCl3 > VinSiCl3 > PrSiCl3. An explanation of the regularities is suggested.
- Belyakova,Komarov,Bykovchenko,Ershov,Chernyshev,Storozhenko
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- CuH-Catalyzed Asymmetric Reductive Amidation of α,β-Unsaturated Carboxylic Acids
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The direct enantioselective copper hydride (CuH)-catalyzed synthesis of β-chiral amides from α,β-unsaturated carboxylic acids and secondary amines under mild reaction conditions is reported. The method utilizes readily accessible carboxylic acids and tolerates a variety of functional groups in the β-position including several heteroarenes. A subsequent iridium-catalyzed reduction to γ-chiral amines can be performed in the same flask without purification of the intermediate amides.
- Link, Achim,Zhou, Yujing,Buchwald, Stephen L.
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- METHOD FOR PREPARING ALKYLALKOXYSILANES
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A method is useful for preparing alkylalkoxysilanes, such as alkylalkoxysilanes, particularly dimethyldimethoxysilane. The method includes heating at a temperature of 150°C to 400°C, ingredients including an alkyl ether and carbon dioxide, and a source of silicon and catalyst. The carbon dioxide eliminates the need to add halogenated compounds during the method.
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Paragraph 0038
(2020/03/29)
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- A process for the production of alkoxy silane (by machine translation)
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The invention belongs to the field of chemical industry, relates to a production process of alkoxy silane, in order to improve the purity of the product. The production process comprises the following steps: A, eliminates the water mellowly enters into the reaction equipment, an esterification reaction with the organic silane; B, after the esterification reaction of the material entering the evaporation apparatus, and distilled to remove the material in a small amount of alcohol; C, in and after the distillation product to get the alkoxysilane; production process the start-up phase, the steps of adding excessive mellow A, the reaction apparatus in the backflow of appears mellowly; in the case of when the mellow backflow, add organochlorosilane, joins the quantity mellowly is reduced to the amount of consumption by the reaction. The invention relates to a simple process for the production of the realization of the alkoxy silane, in particular methyl triethoxy silane production. Relative to the other process reduces the rectifying tower, the circulation evaporator replace, increased water removal system and in the fixed-bed and system. In the reaction process through the control of the temperature, pressure and feed rate, the obtained alkoxy silane in the HCl content of 10 ppm following, purity 99.0% wt or more. (by machine translation)
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Paragraph 0035; 0036
(2017/07/15)
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- Preparation technique of methyltrimethoxy silane
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The invention discloses a preparation technique of methyltrimethoxy silane. By using monomethylhydrodichlorosilane and methanol as raw materials, the technique comprises the steps of alcoholysis dechlorination and dehydrogenation and after-treatment. The technique specifically comprises the following steps: carrying out alcoholysis reaction on the methanol and monomethylhydrodichlorosilane; and after the reaction finishes, neutralizing the reaction solution to the pH value of 6-8 by using a neutralizer, filtering to remove salts so as to obtain a methyltrimethoxy silane crude product, and carrying out atmospheric rectification on the filtrate to obtain the high-purity methyltrimethoxy silane. The low-value monomethylhydrodichlorosilane is converted into the high-added-value product methyltrimethoxy silane which can be directly sold; and the technique effectively reduces the storage danger of the monomethylhydrodichlorosilane, enhances the production safety, and conforms to the requirements for green clean production.
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Paragraph 0026; 0027; 0028; 0029; 0030; 0031; 0032-0051
(2017/06/19)
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- Amorphous silicon: New insights into an old material
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Amorphous silicon is synthesized by treating the tetrahalosilanes SiX4 (X=Cl, F) with molten sodium in high boiling polar and non-polar solvents such as diglyme or nonane to give a brown or a black solid showing different reactivities towards suitable reagents. With regards to their technical relevance, their stability towards oxygen, air, moisture, chlorine-containing reaction partners RCl (R=H, Cl, Me) and alcohols is investigated. In particular, reactions with methanol are a versatile tool to deliver important products. Besides tetramethoxysilane formation, methanolysis of silicon releases hydrogen gas under ambient conditions and is thus suitable for a decentralized hydrogen production; competitive insertion into the MeO-H versus the Me-OH bond either yields H- and/or methyl-substituted methoxy functional silanes. Moreover, compounds, such as MenSi(OMe)4-n (n=0-3) are simply accessible in more than 75% yield from thermolysis of, for example, tetramethoxysilane over molten sodium. Based on our systematic investigations we identified reaction conditions to produce the methoxysilanes MenSi(OMe)4-n in excellent (n=0:100%) to acceptable yields (n=1:51%; n=2:27%); the yield of HSi(OMe)3 is about 85%. Thus, the methoxysilanes formed might possibly open the door for future routes to silicon-based products. Amorphous silicon is easily synthesized from tetrahalosilanes SiX4 (X=Cl, F) and molten sodium in different solvents. Reactivity studies prove the resulting materials as versatile tools for the formation of technical important silanes, such as the silicon chloro-, alkoxy-, and methylalkoxy-substituted derivatives (see figure; bl=black, br=brown).
- Spomer, Natalie,Holl, Sven,Zherlitsyna, Larissa,Maysamy, Fariba,Frost, Andreas,Auner, Norbert
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p. 5600 - 5616
(2015/03/30)
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- METHOD FOR PREPARING AN ORGANO-FUNCTIONAL SILANE
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A process includes reacting an organometallic cuprate and a silicon precursor in the presence of a solvent. The process produces a reaction product including an organo-functional silane.
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Paragraph 0025
(2014/05/24)
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- COSMETIC TREATMENT METHOD COMPRISING THE APPLICATION OF A COATING BASED ON AN AEROGEL COMPOSITION OF LOW BULK DENSITY
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The present invention relates to a cosmetic treatment method comprising the formation of a coating on keratin fibres characterized in that it comprises: 1) the preparation of an aerogel precursor composition comprising:—at least one organic solvent chosen from acetone, C1-C4 alcohols, C1-C6 alkanes, C1-C4 ethers, which may or may not be perfluorinated, and mixtures thereof and at least one precursor compound that contains:—at least one atom chosen from silicon, titanium, aluminium and zirconium,—at least one hydroxyl or alkoxy function directly attached to the atom chosen from silicon, titanium, aluminium and zirconium by an oxygen atom, and,—optionally an organic group directly attached to the atom chosen from silicon, titanium, aluminium and zirconium by a carbon atom, 2) the removal of the solvent or solvents resulting in the formation of an aerogel composition having a bulk density less than or equal to 0.35 g/cm3, 3) the application to the keratin fibres of the aerogel composition resulting from step 2) or of the aerogel precursor composition resulting from step 1). Advantageously, the molar ratio between the precursor compounds and the solvent is at most 1/20.
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Paragraph 0067
(2014/02/15)
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- METHOD OF PRODUCING A HYDROLYZABLE SILICON-CONTAINING COMPOUND
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The present invention provides a safe, inexpensive, and high yield means of producing a hydrolyzable silicon-containing compound, e.g., an organooxysilane and the like. A compound (A) represented by the general formula R1-O-R2 wherein R1 represents a C4-30, substituted or unsubstituted, tertiary alkyl group or aralkyl group and R2 represents a C1-30, substituted or unsubstituted, monovalent hydrocarbyl group or acyl group, is reacted in the presence of a Lewis acid catalyst with a halosilane (B) represented by the general formula R3mSiX4-m wherein R3 represents the hydrogen atom or a C1-30 substituted or unsubstituted monovalent hydrocarbyl group, X is independently bromine or chlorine, and m represents an integer from 0 to 3.
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Page/Page column 23-24
(2012/07/14)
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- Process for the direct synthesis of trialkoxysilane
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The Direct Synthesis of trialkoxysilane is carried out by conducting the Direct Synthesis reaction of silicon and alcohol, optionally in solvent, in the presence of a catalytically effective amount of Direct Synthesis catalyst and an effective catalyst-promoting amount of Direct Synthesis catalyst promoter, said promoter being an organic or inorganic compound possessing at least one phosphorus-oxygen bond.
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Page/Page column 15-16
(2008/06/13)
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- METHOD FOR PRODUCING ORGANOSILANES
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The invention relates to a method for producing organosilanes by reacting amorphous silicon with appropriate alcohols while forming Si-C compounds. In order to produce organosilanes RnSi (OR) 4-n, X-ray amorphous silicon, which can be produced, for example, by reducing silicon tetrahalides with metals in an inert apolar solvent, are reacted with alcohols while heating.
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Page/Page column 9-10
(2008/06/13)
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- Preparation of branched siloxane
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By reacting a branched siloxane compound of formula (2) containing compounds of formula (1) as an impurity with a disiloxane compound of formula (3) in the presence of an acid compound, there is prepared a branched siloxane of formula (2) containing a reduced level of compounds of formula (1).R1?nSi(OSiR2?3)3-n(OR3)R1?nSi(OSiR2?3)4-nR2?3SiOSiR2?3 R1 is a monovalent hydrocarbon group, R2 and R3 are H or monovalent hydrocarbon groups, and n is 0 or 1.
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Page/Page column 10
(2010/02/10)
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- Use of an organometallic compound to protect and/or strengthen a keratin material, and treatment process
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The use of a composition comprising at least one organometallic compound which may be obtained by partial or total hydrolysis, and partial or total condensation, of at least one metallic precursor, to at least one of protect and strengthen a keratin material.
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- Process for preparing low-chloride or chloride-free alkoxysilanes
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A process for preparing an alkoxysilane with an acidic chloride content of less than 10 ppm by weight, comprising: reacting a chlorosilane with an alcohol in a water-free and solvent-free phase to form a product mixture containing alkoxysilane and residual acidic chloride, with removal of resultant hydrogen chloride from the product mixture, then adding liquid or gaseous ammonia, in an amount corresponding to a stoichiometric excess, based on the content of acidic chloride, to form an ammonia-containing product mixture, treating the ammonia-containing product mixture at a temperature between 10 and 50 DEG C., wherein the ammonia and acidic chloride undergo neutralization, to form a crude product, and optionally, then separating off a salt formed in the course of neutralization, from the crude product, and recovering the alkoxysilane by distilling the crude product.
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- Method for decomposing polysiloxane
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When a polysiloxane or siloxane is contacted with a mixture which comprises an orthoester, a compound having an active hydrogen-containing group and an acid catalyst, it is easily decomposed even at room temperature to provide a silicon compound having a lower molecular weight such as an alkoxysilane.
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- Consecutive Reactions of Diethoxydimethylsilane and Triethoxymethylsilane with Methoxide Ions in Methanol Solution
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The consecutive reactions of (CH3)2Si(OC2H5)2 and CH3Si(OC2H5)3 with methoxide ions were investigated in methanol solutions.The reverse transesterification reactions with ethoxide ions could be neglected in both cases since the concentration of ethoxide in methanol solution was assumed to be low due to the fast equilibrium reaction C2H5O- + CH3OH C2H5OH + CH3O-.The progress of the reactions was followed by monitoring the formation of ethanol with a Fourier-transform infrared spectrometer.All rate constants were determined at 295 K.The reactions between the dialkoxydimethylsilanes and methoxide ions were assumed to consist of two consecutive steps that can be represented by the net reaction; (CH3)2Si(OC2H5)2 + 2 CH3O- -> (CH3)2(OCH3)2 + 2 C2H5O-.The two consecutive rate constants were established as 1.93 +/- 0.12 M-1 s-1 and 1.00 +/- 0.12 M-1 s-1, respectively.The consecutive rate constants for the reactions between the trialkoxymethylsilanes and methoxide ions can be written according to the total reaction; CH3Si(OC2H5)3 + 3 CH3O- -> CH3Si(OCH3)3 + 3 C2H5O-.The three rate constants corresponding to each consecutive step were established as 1.12 +/- 0.09 M-1 s-1, 0.82 +/- 0.10 M-1 s-1, and 0.51 +/- 0.06 M-1 s-1, respectively.
- Jaeglid, Ulf,Lindqvist, Oliver
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- 1,3-disilacyclobutanes and the method for producing thereof
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The present invention relates to a process for preparing 1,3-disilacyclotutanes by pyrolyzing alkoxytrisilaalkaness at a temperature of from 400° C. to 800° C. at the atmospheric pressure or under the vacuum. This is a new synthetic route of 1,3-disilacyclobutanes which employs readily available starting materials without using alkaline metals or magnesium, affords very good yields, produces very clean product mixtures separable by distillation, and tolerates functionality on silicon.
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- Polyfunctional carbosilanes and organosilicon compounds. Synthesis via grignard reactions
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The THF solutions of (triethoxysilyl)methyl magnesium chloride are stable at low temperatures. At 20°C, the Grignard reagent underwent intermolecular condensation, providing a simple synthesis of cyclic carbosilanes derivatives. The cross-coupling reaction with organic halides also afforded a facile route to a variety of trifunctional organosilicon compounds.
- Brondani, Dalci J.,Corriu, Roben J. P.,El Ayoubi, Sabar,Moreau, Joel J. E.,Man, Michel Wong Chi
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p. 2111 - 2114
(2007/10/02)
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- Method of purification of alkoxysilanes
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A halide-containing alkoxysilane is brought into contact with a zinc metal or an organic zinc compound to remove the halide from the alkoxysilane, simply and effectively, to thereby provide a purified alkoxysilane.
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- Process for producing alkoxysilanes
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In a process for producing an alkoxysilane represented by general formula (III): wherein a represents a number of 0 to 2, b represents a number of 1 to 3, c represents a number of 0 to 2, the sum of a+b+c represents a number of not greater than 4 which comprises reacting a chlorosilane represented by general formula (I): wherein a and b have the same meanings as described above and a+b represents a number of less than 4, with an alcohol represented by general formula (II); wherein R represents an alkyl group, a process for producing said alkoxysilanes characterized in that the reaction of the chlorosilane and the alcohol is performed in the co-presence of (a) an inert low boiling solvent having a boiling point lower than the boiling point of the objective alkoxysilane represented by general formula (III) and a difference in boiling point is not smaller than 4° C. and (b) an inert high boiling solvent having a boiling point higher than the boiling point of the objective alkoxysilane and a difference in boiling point is not smaller than 4° C.
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- Method for silylating aromatic imides and silylimides made therefrom
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A method is provided for silylating aromatic imides by effecting reaction between a polysilane and such aromatic imide in the presence of an effective amount of a catalyst of a transition metal such as palladium.
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- Method of making alkylalkoxysilanes
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A process is provided for making alkylalkoxysilane by reacting a C1 -C5 alkyl alcohol in the presence of an effective catalytic amount of copper metal and an alkali metal carboxylate catalyst. Preferably, silicon and methanol are reacted in the presence of copper metal and potassium formate catalysts to produce methyltrimethyoxysilane.
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