Silicon tetraethoxide

Friberg SE, Yang CC, Sjoblom J (1992) Amphiphilic Associahon Structiues and the Microemulsion Gel Method for Ceramics - Influence on Original Phase Regions by Hydrolysis and Condensahon of Silicon Tetraethoxide. Langmuir 8 372-376... 

Polymer and precursors (FeCl3, iron(III) acetate, titanium isopropoxide, silicon tetraethoxide, and copper(II) chloride) dissolved in organic solvent (acetone, ethyl acetate) and cast onto microscopic slides precursors in situ hydrolyzed... 

The most common process for making inorganic silica polymers is the reaction of water with silicon tetraethoxide (TEOS) in a solvent of ethanol. The major factor controlling the properties of the silica polymers is the solution pH, with water concentration being second. In acidic solution, the resulting polymers yield gels that are clear, have very fine porosity, and form fully dense silica at relatively low temperatures (<800 °C). In contrast, in alkaline... 

Mechanism. Under acidic conditions and with adequate water, the hydrolysis of silicon tetraethoxide (and tetramethoxide) is fast and complete... 

Friberg, S.E., Yang, C.-C., and Sjoblom, J., Amphiphilic association structures and the microemul-sion/gel method for ceramics influence on original phase regions by hydrolysis and condensation of silicon tetraethoxide, Langmuir, 8, 372, 1992. 

Beilstein Handbook Reference) AI3-15098 BRN 1422225 Dynasil A EINECS 201-083-8 ES 100 ES 28 Ethyl orthosilicate Ethyl silicate Ethyl silicate, ((EtO)4Si) Etylu krzemian HSDB 534 NSC 4790 Orthosilicic acid, tetraethyl ester Silane, tetraethoxy- Silester Silicate d ethyle Silicate tetraethylique Silicic acid, tetraethyl ester Silicic acid H4Si04), tetraethyl ester Silicon ethoxide Silicon tetraethoxide Silikan L TEOS Tetraethoxysilane ... 

Even when using the lUPAC convention there is still the distinct possibility of encountering confusion when reading the literature. For example, silicon tetraethoxide... 

TABLE 22.3 Effect of Distillation on the Purity of Silicon Tetraethoxide ... 

Kato, M. Tanaka, H. Ebulliometric measurement of vapor-liquid equihbiia for four binary systems methanol + sihcon tetramethoxide, methanol + silicon tetraethoxide, ethanol -l- sihcon tetramethoxide, and ethanol -l- silicon tetraethoxide J. Chem. Eng. Data 1989,34, 206-209... 

Stober et al. (56) carried out a systematic study of the factors that control the preparation of fine, uniform Si02 particles by the hydrolysis of silicon alkoxides in the presence of NH3. The NH3 served to produce pH values in the basic range. For the hydrolysis of silicon tetraethoxide, Si(OC2H5)4, referred to commonly as TEOS, with ethanol as the solvent, the particle size of the powder was dependent... 

Figure 2.21 Correlation between particle size and the concentrations of water and ammonia in the hydrolysis of a solution of 0.28 mol/dm silicon tetraethoxide in ethanol. (From Ref. 56.)...

For a polymeric silica gel prepared by the hydrolysis of silicon tetraethoxide, =0.25 J/m k — 10 nm and po =0.50, so that tensile stresses, cracking will result. For a colloidal silica gel, the corresponding values are y v 0.25 J/ m, Iq 100 nm, po = 0.25, and CTmax 3 MPa that is, the maximum stress is considerably smaller. 

Similarly titanium trichloride monoethoxide was obtained by reactions of titanium tetrachloride with silicon monochloride triethoxide or silicon tetraethoxide (Eqs 2.162 and 2.163). 

The thermal decomposition of silicon tetraethoxide yields sUicon oxides at higher... 

Mg-Ti catalyst was synthesized by reducing titanium tetrabutoxlde with n-butyImagneslum chloride in the presence of silicon tetraethoxide, and treating with diisobutyl phthalate and then with a mixture of TiCl, dibutylether, and diisobutyl phthalate. 

By far the most used synthetic approach is to partially pre-hydrolyze silicon tetraethoxide (TEOS) with a small amount of acidic water in order to form Si(OEt)4.x(OH)x species (x ). The condensation between silicon species being very slow at low pH, hydrolyzed silicon precursors would then react with Ti(OR)4 to form Si-OTi bonds as follows ... 

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