Synthesis of Silylated Derivatives of a Layered Polysilicate Kanemite with Mono-, Di-, and Trichloro(alkyl)silanes

Abstract

Interlayer modification of a layered polysilicate kanemite was performed by silylation with mono-, di-, and trichloro(alkyl)silanes. The introduction of silyl groups into the interlayer region was confirmed by XRD, IR, 13C NMR, and 29Si NMR. The layered structures of the silylated products were confirmed by swelling behavior upon adsorption of n-alkyl alcohols. The amounts of attached alkylsilyl groups varied with the number of functional groups as well as the alkyl chain length in the silylating agents. The products modified with alkyltrichlorosilanes exhibited various interlayer structures due to the different arrangements and/or conformations of the alkyl chains, depending on the chain lengths. The BET surface areas were relatively large (up to ∼480 m2 g-1) when short-chain alkyltrichlorosilanes were used, and decreased substantially to nonporous structures with increasing chain length. In addition to the inherent six-membered rings in the single layered silicate sheets of kanemite, new five- and six-membered rings were formed onto the silicate frameworks when dichloro- and trichlorosilanes were used for silylation. This leads to a new method for constructing novel organosilicate nanomaterials utilizing layered silicates.