Synthesis of interlamellar silylated derivatives of magadiite and the adsorption behavior for aliphatic alcohols

Interlayer silanol groups of a layered polysilicate magadiite (Na ₂H₂Si₁₄O₃₀·nH₂O) were silylated with octyltrichlorosilane via dodecyltrimethylammonium magadiite as the intermediate. Three organic derivatives with different degrees of silylation were prepared by varying the amount of the silylating reagent. Aliphatic alcohols with different alkyl chain lengths (n = 8, 12, and 16) were adsorbed into these derivatives at room temperature, and the adsorption behavior was examined. The basal spacings of the derivatized silicates were expanded after the adsorption, and larger spacings were observed when the derivatives with lower degrees of silylation and the alcohols with longer chain lengths were used. Because intercalated alcohols and alcohols taken up in the intercrystal spaces were desorbed by drying, the amounts of intercalated alcohols were estimated by surveying the relationship between the variation in the basal spacing and the amounts of alcohols in the samples treated under various drying conditions. Larger amounts of alcohols were adsorbed onto the derivatives with lower degree of silylation, indicating a possible control of the interlayer nanospace by varying the amount of grafting alkylsilyl groups.