Silicon compounds, organic tetraethoxysilane

Tetraethoxysilane is the main raw stock in the production of valuable silicone products, e.g. heat-resistant and insulating varnishes, or oli-goethylsiloxane liquids. The most important chemical property of tetraethoxysilane is its ability to replace the ethoxyl group with an organic radical under the effect of metalorganic compounds, i.e. to form substituted ethers of orthosilicon acid, which are the raw stock in the production of the silicone products mentioned above. 

Here the phenyl silicate represents a compound of an acidic alcohol with a nonacidic acid. Considerations such as these have led to the term ether as a more correct name from the standpoint of organic chemistry, and yet not all the carbon ethers hydrolyze as readily as do these silicon analogs. The names tetraethoxysilane and tetra-phenoxysilane would be more correct, although unwieldy. 

Thermal decomposition of two starting materials in inert organic solvent may provide a convenient route for the synthesis of mixed oxides or precursor of mixed oxides. For example, when a mixture of aluminum isopropoxide and tetraethoxysilane (tetraethylorthosilicate) in a 3 1 ratio is decomposed in toluene, an amorphous product is obtained." Note that thermal decomposition of the former compound alone yields %-alumina, while the latter compound alone does not decompose at the reaction temperature." Mullite is crystallized by calcination of the product at 900°C." It is known that the crystallization behavior of mullite from the precursor gel depends on the homogeneity of mixing of aluminum and silicon atoms in the precursor when the precursor gel has atomic scale homogeneity, mullite is crystallized at 900°C, and the gel with homogeneity in a nano... 

The synthesis of titanium silicates by basic and acidic hydrolysis in an organic-water media were carried out at 80-150 C in an autoclave with stirring (150-200 rpm) at autogenic pressure (2.5-4.5 at.). As silicon sources tetraethoxysilane and silicic acid have been used. As metal sources the metal-organic compounds alcoholates, stearates, acetylacetonates, acetates or mineral salts have been used. Hexamethylenetetramine, N,N-dimethylocteIamine, monoethanolamine were used as the structure-directing agents. 

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