Dynamit Nobel Aktiengesellschaft

Volker Hunger

Arnold Lenz

Rainer Haase

Hermann Richtzenhain

Wilhelm Joch

Wilhelm Flick

An improvement in the preparation of orthosilicic acid tetraalkyl esters by reaction of metallic silicon with alcohol in the presence of alkali alcoholate is disclosed, the improvement residing in carrying out the reaction in the co-presence of an ether alcohol or alkanolamine as cocatalyst.

Method for preparation of orthosilicic acid tetraalkyl esters

A process for the preparation of an aqueous alkali metal polysilicate solution having an SiO.sub.2 : alkali metal oxide mole ratio of 2.5 - 5.5 : 1 and a silica content of 16 - 23% by weight which comprises contacting a tetraalkoxysilane of the formula Si(OR).sub.4 wherein each R is independently a straight or branched-chain alkyl group of 1 to 3 carbon atoms with an aqueous alkali metal hydroxide solution at a temperature between room temperature and the boiling point of the reaction mixture and at a temperature up to 100.degree. C. distilling over alcohol formed by the reaction of the silane with the alkali metal hydroxide.

Aqueous solutions of alkali polysilicates

A process for the preparation of an aqueous alkali metal polysilicate solution having an SiO.sub.2 : alkali metal oxide mole ratio of 2.5 - 5.5 : 1 and a silica content of 16 - 23% by weight which comprises contacting a tetraalkoxysilane of the formula Si(OR).sub.4 wherein each R is independently a straight or branched-chain alkyl group of 1 to 3 carbon atoms with an aqueous alkali metal hydroxide solution at a temperature between room temperature and the boiling point of the reaction mixture and at a temperature up to 100.degree.C. distilling over alcohol formed by the reaction of the silane with the alkali metal hydroxide.

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Volker Hunger