Organic quaternary ammonium silicates, rapid

In the first section of this paper, formation of silicate species with cage-like structures in organic quaternary ammonium silicate solutions are reviewed. In the last section, the process of the rapid selective formation of the silicate solids having the... 

Rapid Solidification of Organic Quaternary Ammonium Silicates... 

In this section, the results of our study on the rapid solidification of organic quaternary ammonium silicates are presented. 

I. Hasegawa and S. Sakka, Silicate Species with Cagelike Structure in Solutions and Rapid Solidification with Organic Quaternary Ammonium Ions, Zeolite Synthesis (ACS Symposium Series 398) Am, Chem. Soc., Washington, DC 1989, p.140/51... 

Silicate Species with Cagelike Structure in Solutions and Rapid Solidification with Organic Quaternary Ammonium Ions... 

Tetramethylammonium or (2-hydroxyethyl itrimethylammonium silicate solid, consisting solely of the SigC Q0- silicate structure, was abruptly separated out by cooling the single phase solution which was obtained after an exothermal reaction by mixing the organic quaternary ammonium hydroxide aqueous solution and tetraethoxysilane. The change between the solid and the solution was reversible and very rapid. 

Some of the available quaternary ammonium silicates have been listed by Weldes and Lange (19), although the nature of the ion was not disclosed. Molar ratios of Si0j (NR4)20 range from 1,2 1 to 30 1 and silica contents of the solutions from 10 to 45%. Hydrated amorphous powders are also listed with ratios of 15.6 1 and 19.7 1. These dissolve rapidly in water and are remarkably soluble in mixtures of water and water-miscible organic solvents such as acetone and the lower alcohols. 

Organic bases in water interact with silica in a manner that would be expected from the resulting pH. Strong quaternary ammonium bases like tetramethylammonium hydroxide dissolve silica rapidly, forming the silicate salt. 

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