1992-48-9Relevant articles and documents
Pentacoordinate dihydridosilicates: Synthesis, structure, and aspects of their reactivity
Corriu, Robert J. P.,Guérin, Christian,Henner, Bernard J. L.,Wang, Qunjie
, p. 3574 - 3581 (1991)
The reactions of H- with trialkoxysilanes provide a unique and facile entry to anionic pentacoordinate dihydridosilicates [H2Si(OR)3]-, isolated as stable crystalline products in the case of bulky R groups (R = i-Pr, s-Bu, c-C6H11). Their dynamic behavior (R = i-Pr and s-Bu) has been investigated by 29Si and variable-temperature 1H NMR. Intramolecular exchange of H atoms between axial and equatorial sites is indicated and was found to be significantly dependant on the nature of the solvent. Compared to HSi(OR)3, K[H2Si(OR)3] are versatile reagents: (1) the silicon atom is an electrophilic center and this leads to nucleophilic displacements of the alkoxy groups with Grignard reagents and organolithiums; (2) they are able to reduce very easily carbonyl derivatives to alcohols without any catalyst; (3) they react with primary halides through an ionic mechanism leading to the alkane; (4) the reaction with benzylic halides is more complex and affords the dimer as the major product, the formation of which can be explained by a SET process; (5) the ability to donate one electron is confirmed in the reaction with Cp(CO)2FeI and by direct ESR observation of stable radical intermediates.
BIOREMEDIATION USING CO-METABOLISM SUBSTRATES
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, (2020/06/08)
Certain disclosed embodiments concern a bioremediation composition comprising microbial cells, at least one co-metabolism substrate to induce selected enzyme production by the microbial cells, and a bead or gel encapsulating the microbial cells, such as bacterial or fungi cells, and the at least one co-metabolism substrate. For certain embodiments, the substrate is a slow release compound, such as an orthosilicate that hydrolyzes to produce an alcohol growth substrate. Embodiments of a method for using the composition to transform contaminants of concern also are disclosed.
Reaction of silicon with alcohols in autoclave
Krylova,Egorov,Nefedov
, p. 260 - 266 (2017/07/11)
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.
Precursors for silica or metal silicate films
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Page/Page column 3, (2008/06/13)
A composition selected from the group consisting of bis(tert-butoxy)(isopropoxy)silanol, bis(isopropoxy)(tert-butoxy)silanol, bis(tert-pentoxy)(isopropoxy)silanol, bis(isopropoxy)(tert-pentoxy)silanol, bis(tert-pentoxy)(tert-butoxy)silanol, bis(tert-butoxy)(tert-pentoxy)silanol and mixtures thereof; its use to form a metal or metalloid silicate layer on a substrate and the synthesis of the mixed alkoxysilanols.
PRECURSORS FOR SILICA OR METAL SILICATE FILMS
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Page/Page column 2, (2008/06/13)
A composition selected from the group consisting of bis(tert-butoxy)(isopropoxy)silanol, bis(isopropoxy)(tert-butoxy)silanol, bis(tert-pentoxy)(isopropoxy)silanol, bis(isopropoxy)(tert-pentoxy)silanol, bis(tert-pentoxy)(tert-butoxy)silanol, bis(tert-butoxy)(tert-pentoxy)silanol and mixtures thereof; its use to form a metal or metalloid silicate layer on a substrate and the synthesis of the mixed alkoxysilanols.
Orthosilicate-mediated esterification of monosubstituted phosphinic acids
Dumond, Yves R.,Baker, Rhonda L.,Montchamp, Jean-Luc
, p. 3341 - 3344 (2007/10/03)
(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.
Contributions to the chemistry of silicon-sulphur compounds LVI. The imidazole catalyzed alcoholysis of the isosteric isobutyl(isopropoxy)silanethiols i-Bun(i-PrO)3-nSiSH (n = 0-3)
Pikies, J.,Wojnowski W.
, p. 305 - 312 (2007/10/02)
The kinetics of the imidazole-catalyzed alcoholysis of the isosteric silanethiols i-Bun(i-PrO)3-nSiSH (I) with n = 0-3 in benzene and acetonitrile have been investigated.The alcoholysis of Si-S bond in I is generally first order with respect to both the silanethiol and the catalyst.At low alcohol concentrations the order with respect to alcohol tends to be zero.A mechanism involving an attack of a nucleophilic catalyst on silicon in I in the rate-determining step is proposed.In MeCN solution the reactivities of silanethiols decrease in the sequence i-Bu(i-PrO)2SiSH > i-Bu2(i-PrO)SiSH > (i-PrO)3SiSH > i-Bu3SiSH.The anomeric effect seems to determine the conformations and the reactivities of these silanethiols.
Hetero-?-Systeme XVI. Alkoxysilylene (Alkoxysilandiyle)
Maier, G.,Reisenauer, H. P.,Schoettler, K.,Wessolek-Kraus, U.
, p. 25 - 38 (2007/10/02)
Dimethoxysilylene (2) reacts with acetylene or dimethylacetylene to form 1,4-disilacyclohexadienes in very good yields.The known addition reactions of dichloro or dimethylsilylene with olefins cannot be carried out, with the exception of the addition to 2,3-dimethylbutadiene.The UV spectrum of dimethylsilylene is also markedly different from those of alkylsubstituted silylenes.The UV absorptions of matrix-isolated alkoxysilylenes, prepared by thermolytically induced flash extrusion from disilanes or benzosilepines, show a surprisingly large hypsochromic shift.This effect can be correlated with semi-empirical calculations.
