Intercalation Compounds of KHSi 2O5 and Hz Si 2O5 with Alkylammonium Ions and Alkylamines

Abstract By acid leaching, the layer silicate, KH 2 Si 2 O 5 , can be converted into a phyllodisilicic acid, H 2 Si 2 O 5 , which is a crystalline hydrated silica. Both products react with aqueous solutions of n-alkylammonium salts, or n-alkylamines, to form organic intercalation derivatives with larger basal spacings than the original materials. The basal spacings of the compounds obtained with the silicic acid increase with length of the alkyl chain. With the silicate, however, the increase is nearly the same (about 2,5 - 3.0 å) for all short-chain ammonium ions (number of carbon atoms n o <7). Longer chains give values of the same order of magnitude as with the silica. Treatment of the short-chain alkylammonium derivatives with the corresponding amines increases their spacings markedly, nearly to those of the H 2 Si 2 O 5 -amine derivatives.