- Reaction of silicon with alcohols in autoclave
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A reaction of activated silicon with alcohols in an autoclave at 240—270 °C was studied. It was found that primary alcohols form tetraalkoxysilanes Si(OR)4 with high selectivity (up to 97%), while the secondary PriOH gave a mixture of compounds HSi(OPri)3, Si(OPri)4, HSi(OPri)2OSi(OPri)2H, HSi(OPri)2OSi(OPri)3, and Si(OPri)3OSi(OPri)3 with the predominance of trialkoxysilane (up to 67%). Carrying out the reaction under the indicated conditions has the advantage of experimental simplicity, reagent availability, high conversion of silicon, good isolated yields of products.
- Krylova,Egorov,Nefedov
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p. 260 - 266
(2017/07/11)
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- Direct synthesis of tetraalkoxysilanes from silica and alcohols
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A new simple and efficient process for synthesizing tetraalkoxysilanes (TROS) directly from silica and alcohols was developed using molecular sieves as dehydrating agents. Using this method, a variety of TROS (R = ethoxy, n-propoxy, or n-butoxy) were obtained over 70% yields within 6 h. We also employed various natural silica sources in this process for practical applications.
- Fukaya, Norihisa,Choi, Seong Jib,Horikoshi, Toshio,Kataoka, Sho,Endo, Akira,Kumai, Hiroshi,Hasegawa, Minoru,Sato, Kazuhiko,Choi, Jun-Chul
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supporting information
p. 2224 - 2226
(2017/03/21)
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- PRODUCTION METHOD FOR ALKOXYSILANES
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Provided is a method for efficiently producing alkoxysilanes that are useful as various functional chemicals. In order to produce alkoxysilanes efficiently, an ethoxy- or methoxysilane and an alcohol are caused to react using, as a catalyst, for instance an inorganic solid acid having a regular-pore and/or layered structure. Zeolites, montmorillonites or the like can be used as the inorganic solid acid. When a zeolite is used as the catalyst, the silica/alumina ratio of the zeolite ranges preferably from 5 to 1000. The reaction can be promoted through irradiation of microwaves.
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Paragraph 0096; 0097; 0115
(2016/01/30)
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- Heterogeneous-gold-catalyzed acceptorless cross-dehydrogenative coupling of hydrosilanes and isocyanic acid generated in situ from urea
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Support structure: In the presence of gold nanoparticles supported on alumina (Au/Al2O3), various hydrosilanes can be converted into the corresponding silyl isocyanates using urea as an isocyanate source. The observed catalysis is truly heterogeneous, and the retrieved Au/Al 2O3 catalyst can be reused several times without any loss of its high catalytic performance. Copyright
- Taniguchi, Kento,Itagaki, Shintaro,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 8420 - 8423
(2013/09/02)
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- Versatile method for introduction of bulky substituents to alkoxychlorosilanes
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The reactions of various alkoxytrichlorosilanes prepared in situ from tetrachlorosilane and alcohols, with Grignard reagents bearing a bulky substituent such as the isopropyl, sec-butyl, and cyclohexyl group afforded triisopropyl-, tri(sec-butyl)-, and tricyclohexylalkoxysilane in high yields. The reactions of n-butoxytrichlorosilane with these Grignard reagents produced triisopropyl-, tri(sec-butyl)-, and tricyclohexyl(n-butoxy)silane in 94%, 96%, and 92% yields, respectively. Methoxymethyldichlorosilane reacted with the same Grignard reagents to give diisopropyl-, di(sec-butyl)-, and dicyclohexylmethoxymethylsilane in 84%, 83%, and 83% yields. Treatment of methoxydimethylchlorosilane with the Grignard reagents readily afforded isopropyl-, sec-butyl-, and cyclohexylmethoxydimethylsilane in excellent yields. Similar treatment of methoxydimethylchlorosilane with tert-butylmagnesium chloride gave tert-butylmethoxydimethylsilane in 62% yield.
- Masaoka, Shin,Banno, Tadashi,Ishikawa, Mitsuo
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p. 182 - 192
(2007/10/03)
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- Orthosilicate-mediated esterification of monosubstituted phosphinic acids
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(matrix presented) Monosubstituted phosphinic acids are esterified with orthosilicates in excellent yields. Phosphinylidene-containing acids react selectively under these conditions, while disubstituted phosphinic acids and phosphonic acids remain unchanged. One-pot procedures are also described for the preparation of phosphinate esters from an alcohol. This novel method provides a convenient and general alternative to more commonly employed conditions such as diazomethane or carbodiimide.
- Dumond, Yves R.,Baker, Rhonda L.,Montchamp, Jean-Luc
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p. 3341 - 3344
(2007/10/03)
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- Transesterification of Ethoxysilanes with Butyl Acetate in the Presence of Alkoxy Derivatives of Titanium
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It was found for the first time that alkoxy derivatives of titanium of various structure act as effective catalysts in alkoxysilane transesterification with esters. Kinetic studies showed that both the catalytic activity of alkoxytitaniums and the reactivity of alkoxysilanes are structure-dependent. The preparative usefulness of titanium tetraalkoxides was demonstrated.
- Khonina,Suvorov,Soldatova,Kozlov
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p. 729 - 732
(2007/10/03)
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- Catalytic Activity of Titanium Alkoxy Derivatives in Alcoholysis of Ethoxysilanes
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Titanium tetraalkooxides, regardless of their structure, are effective catalysts for alcoholysis of ethoxysilanes. Titanium alkoxychlorides demonstrate the highest catalytic activity, whereas the catalytic activity of coordination-saturated titanium compounds is the lowest. The influence of the catalyst nature on its activity is analyzed.
- Khonina,Kochneva,Suvorov
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- Transesterification Reaction of Tetraethoxysilane and Butyl Alcohols
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Tetraethoxysilane was treated with Amberlyst 15 cation-exchange resin in the presence of butyl alcohol.On treating the mixture of tetraethoxysilane and 1-butanol, the transesterification took place in which butoxyl groups were substituted for ethoxyl groups in tetraethoxysilane.The degree of the transesterification depended on the molar ratio of tetraethoxysilane to 1-butanol of a mixture.The distribution of alkoxysilane species present in the tetraethoxysilane-1-butanol solution was compared with the tetrabutoxysilane-ethanol solution, and it was found that the degree of the transesterification depended on the ratio of numbers of alkyl groups in tetraalkoxysilane and alcohol used.The time required for equilibrium in the distribution of alkoxysilane species in the solution was different with the variety of butyl alcohol used, suggesting the presence of steric effect of butyl alcohols on this reaction.
- Hasegawa, Isao,Sakka, Sumio
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p. 4087 - 4092
(2007/10/02)
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- Conformational transmission in silatranes. Confirmation of the pentacoordinated structure in solution
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A 300-MHz (1)H-NMR conformational analysis study of a set of pentacoordinated silicon compounds (silatranes) and their tetracoordinated counterparts is presented.The solution conformation of the silatranes shows a close resemblance to known X-ray structures, although the silatrane conformation was found to depend upon the solvrnt polarity.Comparison of the conformation of a 2-methoxyethoxy fragment in the tetra-and pentacoordinated systems showed the existence of conformational transmission, similar to that known for phosphorus compounds.Enhanced electrostatic repulsion between the vicinal oxygens in the 2-methoxyethoxy fragment produces a trans conformation around the C-C bond in the pentacoordinated silatranes.The conformational transmission effect is smaller in silatranes than in phosphorus compounds, due to a relatively weak fifth bond.
- Genderen, Marcel H. P. van,Buck, Henk M.
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p. 449 - 452
(2007/10/02)
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