Paints, adhesives, cements, and corrosion control are just some of t h e industrial applications of these remarkable alkali metal and organic ammonium silicates propertfes of oluble sdicates are systems containing varying prcportions of an alkali metal or quaternary ammonium ion and silica @iot), usually with at least some water.
Alkaliorganische Verbindungen werden von Azulenen an der cyclischen Fulven-Doppelbindung addiert. Durch Hydrolyse dieser Additionsverbindungen entstehen Dihydro-azulene, die zu Azulenen dehydriert werden, welche in 4oder 8-Stellung substituiert sind. R +H,O -Me'OH (Ill) entstehen, wobei der organische Rest I an C-4 oder C-8 (beide sind in dem unsubstituierten System identisch) tritt. Ein solcher Reaktionsverlauf entsprache auch der polaren Struktur des Azulens, denn nach v *) s. auch K. HAFNER und H.
Die Beobachtung, daD bereita dee durch Aufspaltung des Pyridins unmittelbar zu erhaltende Produkt (IX) rnit Cyclopentadien in Gegenwart von Natriumalkoholat kondensiert, vereinfacht die Darstellung des Fulvens (VI) sehr.VI spaltet bei ca. 250 OC, besonders vorteilhaft in organischen basisohen Lbsungsmitteln, recht schnell N-Methyl-anilin ab und liefert in etwa 73proz. Ausbeute Azulen. Das A d e n ist nach einer einfachen Sublimation des Rohprodukts schmelzpunktsrein. Reinigung durch Chromatographie oder iiber das Trinitrobenzolat ist nicht nbtig.2) Die nahe Beziehung zwischen Glutacon-dialdehyd und Pyri-
The preparation and properties of stable aqueous amine and ammonium silicate solutions by simple ion exchange methods are described. The mole ratio range of amine silicates is between 2 and 10 SiO?/amine, and of the ammonium silicates between 2 and 6 SiO>/(NH4)20. These solutions are stable for long periods of time at moderate concentrations.CRYSTALLINE quaternary ammonium silicates have been known for some time (Merrill and Spencer, 1951) and water-soluble alkali metal-quaternary ammonium double silicates have been described (Weldes, 1970).Simple amine and ammonium silicates have not been known before. This study shows that stable amine and ammonium silicate solutions can be prepared by treating a mixture of a water-soluble amine or ammonia and an alkali metal silicate solution with properly pretreated cation exchange resins (Weldes, 1967; Weldes and Derolf, 1967).A number of attempts to prepare ammonium silicate solutions are described in the literature, but none have formed ammonium silicate solutions of low alkali metal ion content and small average particle size.Efforts to prepare ammonium silicates directly have failed. Ammonium hydroxide is not a strong enough base to dissolve silica gel even under conditions of elevated temperature and pressure. Silica sols stabilized with ammonia have been known for some time. Usually the sol has been prepared by a well known process and then stabilized by addition of ammonia as an alkaline stabilizing agent (Deribere, 1942;Kuhn, 1953). I n other cases, silica gel has been peptized by treating the gel under various conditions with ammonium hydroxide (Griessbach, 1933;Schwarz, 1916). This method also leads to stabilized sols and not to ammonium silicates. Such stabilized sols have also been prepared by treating a sodium silicate solution with an ion exchange resin in the ammonia form (Vorhees, 1949;Wolter, 1954). In these cases substantial amounts of alkali metal ions are left in the system and stabilized sols are obtained. ExperimentalMaterials. The alkali metal silicates used were commercial products produced by the Philadelphia Quartz Co. They had the following composition: S 35 sodium silicate, weight ratio 3.75 Si02/Nae0, 6.75% NazO, 25.3% SiO?, 67.9"~ H 2 0 ; N sodium silicate, weight ratio 3.22 SiOe/ NazO, 8.90% Na20, 28.7% Si02, 62.4% H 2 0 ; and D sodium silicate, weight ratio 2.0 Si02/Na20, 14.7% N a 2 0 , 29.4% SiO?, 55.8% water.Commercial grade water-soluble amines used included monoethanolamine from the Eastman Kodak Co., diethanolamine and morpholine from the Union Carbide Chemicals Co., triethanolamine from the Fisher Scientific Co., and diethylamine from the Fisher Scientific Co.The cation exchange resin found most useful for this exchange reaction was Amberlite IR-124, a highly crosslinked nuclear sulfonic acid type cation exchange resin produced by Rohm & Haas Co. The sodium form has an exchange capacity of 2.1 meq per ml of wet resin. The standard commercial ammonia solutions used had an ammonia content of 29%. Reagent grade ammonium sulfate was used...
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