Smectite like layered silicates with cation exchange capacity ranges from 60 to 90 mequivalent/100g clay were synthesized from LiF, Mg(OH)2 and colloidal silica. The controlled cation exchange capacity achieved by changing the composition of the starting mixture (namely the added LiF amount) successfully influenced the nanostructures of intercalation compounds prepared by the ion exchange with dioctadecyldimethylammonium ion.

Nanospace engineering of porous organic-clay intercalation compounds has been conducted by ion exchange reactions of 1,1′-dimethyl-4,4′-bipyridinium chloride (methylviologen) with different layer charged hectorite-like layered silicates (cation exchange capacity derived from the amount of the cation exchanged: 42, 74, and 85 mequivalent/100 g clay) prepared by the reaction of LiF, Mg(OH)2, and colloidal silica. The nanospace created with silicate layers and 1,1′-dimethyl-4,4′-bipyridinium cations has been used for the adsorption of organic compounds (N,N-dimethylaniline and 2,4-dichlorophenol) in the interlayer spaces of a series of the 1,1′-dimethyl-4,4′-bipyridinium-layered silicate intercalation compounds. All of the intercalation compounds adsorbed N,N-dimethylaniline from aqueous solution. The basal spacing of the intercalates did not change by the adsorption, indicating that the adsorbed N,N-dimethylaniline existed in the interlayer nanospace. The intercalated N,N-dimethylaniline polymerized to develop a purple color when the layered silicates with the cation exchange capacities of 74 and 42 meq/100 g were used. On the other hand, the intercalation compound with a larger content of 1,1′-dimethyl-4,4′-bipyridinium (cation exchange capacity: 85 meq/100 g) suppressed the polymerization (to dimer or trimer) of N,N-dimethylaniline due to the smaller pore. The adsorption capacity of 2,4-dichlorophenol was larger when the 1,1′-dimethyl-4,4′-bipyridinium content was smaller. It is found that the volume of the nanospace formed with 1,1′-dimethyl-4,4′-bipyridinium and silicate layers is controllable by using the layered silicate with varied layer charge density.

Iron-containing hectorite-like layered silicate was synthesized by the reaction of LiF, Mg(OH)2, colloidal silica, and FeCl3 in aqueous suspension at 100 °C for 2 days. From X-ray diffraction and infrared spectroscopic analysis, the formation of hectorite-like layered silicate was shown. Dimethyldioctadecylammonium and 1,1′-dimethyl-4,4′-bipyridinium (methyl viologen) ions were intercalated by cation-exchange reactions into the interlayer space of the iron-containing silicate. The intercalated amounts of both cationic species were larger compared to iron-free layered silicate, showing increase in the layer charge density of the silicate by the incorporation of iron(III). The increase in the layer charge was thought to be derived from isomorphous substitution of silicon(IV) by iron(III) in the silicate layer. The structural iron(III) was reduced to iron(II) by reaction with sodium dithionite, which was shown by a color-change (yellow to green) and the increase in the intercalated amounts of dimethyldioctadecylammonium and 1,1′-dimethyl-4,4′-bipyridinium ions.