Tetraethoxy silane

The high acidity of the unique sulfonic acid function of Nafion can also be utilized by tethering perfluoroalkanesulfonic acid groups to the surface of various silicas. Two approaches have been described to prepare such hybrid organic-inorganic materials. The grafted materials 3 have been prepared by reacting preformed silica materials (MCM-41, SBA-15) with sultone 2 [Eq. (2.31)].165 Co-condensation of tetraethoxy-silane with 4 in the presence of dodecylamine template, in turn, furnished the HMS-based material 5 [Eq. (2.32)].166,167... 

The initial silica sol consisted of 11 ml of tetramethoxy silane (TMOS), 5 mL of distilled water, and 1 drop of 12 N HC1. A monophasic solution was prepared by the sonogel method 9). Under continuous sonication, a total of 30 ml of tetraethoxy silane (TEOS), 7.5 mL of distilled H2O, and 11 mL of TMOS were addded in a dropwise fashion to form the precursor solution. The final silica sol was composed of a 1 1 5 mole ratio of TEOS TMOS H2O. The acid catalyst was present as a... 

To develop ceramic inks, hybrid organic-inorganic sols are first prepared by hydrolyzing methyltriethoxysilane and tetraethoxy-silane together with colloidal silica sol (10 nm in diameter). Ethanol is generated during the hydrolysis and condensation reaction by the silanes. ... 

The use of silyl ethers also provided a good glimpse into the steric effects of the C-H insertion [98], Relative rates were obtained for insertion a to the oxygen atom in silyl protected n-butanol. It was found that the reaction rate increased dramatically as the size of the silyl protecting group decreased, with a 100-fold rate difference between TBDPS and TMS. Complementary steric and electronic effects were observed with the tetralkoxy silane substrates [97,98], hi competition experiments, it was found that the carbenoid derived from diazo ester 99 reacted solely with tetraethoxy silane 123 to form product 126, and not the corresponding tetramethoxy or tetraisopropoxy derivatives 124 or 125 (Scheme 28). Thus, the secondary C-H bonds appear to possess the right balance between steric and electronic requirements for the insertion. 

Silica monoliths are prepared by sol-gel technology starting from alkoxide precursors, such as tetraethoxy-silane or tetramethoxy-silane [23]. The structure of a silica monolith is characterized by an interconnected silica skeleton and bimodal distribution of 1-3-pm macropores (flow through pores) and 10-20 nm mesopores. 

Being a derivative of tetraethoxy silane and due to the presence of Si-G-Si bonds, PEGS reacts with hydroxide ions in analogy to tetraethoxy silane according to... 

The preparation of nanocomposite membranes by intra-membrane growth within a proton exchange membrane was first described by Mauritz et al. [45-47]. The then novelty of this approach and the breadth and depth of these studies warrant the following discussion of the results, which in many ways laid the foundation for future work in this area. This group made use of the hydrophilic ionic cluster regions of Nafion for confined, sulfonic acid group catalysed, hydrolysis/condensation reactions of impregnated alkoxides. Nafion membranes were first swollen in ethanol/water, then tetraethoxy-silane (or aluminium, titanium and zirconium alkoxides) permeated from one side of the membrane. In addition to the concentration profile of in-... 

Kato, M. Tanaka, H. Aizawa, K. Determination of vapor-liquid equUibria by total pressure measurements for four binaiy silicon compound systems tetramethoxysUane -t p-xylene, tetramethoxysUane + n-nonane, tetraethoxysilane + p-xylene, and tetraethoxy silane + n-nonane F/mW Ptoie 1990,55,181-189... 

Scanning electron microscopy Tetraethyl aluminoxane Transmission electron microscopy Tetraethoxy silane Triisobutyl aluminum Trimethyl aluminum... 

Garz6 et all42 reported retention indices for a considerable number of organosilicon compounds, but only two of the compounds were tetraalkoxysilanes, namely tetramethoxy- and tetraethoxy-silane. 

Physical and chemical mapping using AFM and ToF-SIMS are appropriate means for studying surfaces of flame retarded materials. Various interactions may take place between ammonium polyphosphate (APP), pentaerythritol (PER) and tetraethoxy-silane (TES). Whereas the reaction between APP and PER has been described [820], no direct reaction could be found between APP and TES. Marosi et al. [821] have reported imaging ToF-SIMS of APP-PER-ME-TES intumescent flame retarded (IFR) polypropylene. The image prepared on the basis of SiOjc ions proved the existence of a silicone layer between polymer and solid APP particles covered by PER. 

Ferrer M.L., del Monte F. Study of the adsorption process of sulforhodamine B on the internal surface of porous sol-gel silica glasses through fluorescence means. Langmuir 2003 19 650-653 Fujii T., Mabuchi T., Mitsui I. Fluorescence spectra of naphthols during sol to gel transition of tetraethoxy silane by HCl catalyst. Chem. Phys. Lett. 1990 168 5-8 Fujii T., Mabuchi T., Kitamura H., Kawauchi O., Negishi N., Anpo M. Fluorescence spectra of 1-naphthol during the sol-gel process of a mixed aluminum-silicon alkoxide (Si Al = 94 6). Bull. Chem. Soc. Jpn. 1992 65 720-727... 

A. Novel method for solution growth of thin silica films from tetraethoxy silane. Adv. Mater. 2000 12 1434-1437... 

The sintering behavior of an amorphous zircon powder synthesized by sol-gel processing has been studied by Veytizou et al. (2002). Gel samples were prepared from a reactive precursor solution of zirconyl nitrate and tetraethoxy silane. N2-adsorption-desorption measurements on the porous precursor powder of surface area 412 m /g indicated the presence of spheroidal mesoporous cavities with narrow necks created by a packing of spherical particles. The precursor powder with irregularly shaped and different sized agglomerates or aggregates had a microporous volmne of 27 mm /g and a... 

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