Sodium hydroxide-tetraethoxysilane mixture

Sodium Hydroxide-Tetraethoxysilane Mixture. The exothermal reaction in the mixture of sodium hydroxide aqueous solution and... 

Preparation of Solutions. Tetraethoxysilane is used as a silica source. By adding tetraethoxysilane to a tetramethylammonium or a (2-hydroxyethyl)trimethylammonium hydroxide aqueous solution, two kinds of mixtures in which a N/Si ratio was 1.0 and a Si02 concentration was 2.22 mol kg-1 were prepared. For comparison, another mixture consisting of tetraethoxysilane and a sodium hydroxide aqueous solution with a Na/Si molar ratio of 1.0 and a Si02 concentration of 2.22 mol kg-1 was prepared. 

Synthesis of a hyperbranched polyethoxysiloxane. Using a method described in (in print.), a specimen of hyperbranched polyethoxysiloxane was prepared the solution of 25.4 g (0.125 mole) of sodiumoxytriethoxysilane (preliminary prepared by interaction of 5.0 g of sodium hydroxide and 26.1 g of tetraethoxysilane) was added dropwise to the solution of 7.9g (0.132 mole ) of acetic acid in 160 ml of dry toluene with stirring at 0 C. Reaction mixture was stirred for another two hours at room temperature. The precipitated CHaCOONa was filtered and washed with dry toluene on the filter. The solvent was evacuated at room temperature. 21.7 (82%) of triethoxysilanol was prepared and used for the hyperbranched polyethoxysiloxane preparation. Probe of prepared triethoxysilanol was dissolved in dry THF and analized by NMR (THF,39.76 MHz) 8 = -78.49 (s,lSi). 17.2 g(1.01 mole) of... 

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