title: Attachment of the sulfonic acid group in the interlayer space of a layered alkali silicate, octosilicate.
abstract: The surface modification of a layered alkali silicate, octosilicate (Na(2)Si(8)O(17)·nH2O), with a sulfonic acid group was conducted. The sulfonic acid group was attached to the silicate layer by the reaction of octosilicate with phenethyl(dichloro)methylsilane and the subsequent sulfonation of the attached phenethyl groups with chlorosulfonic acid. The modified octosilicate is a solid acid as indicated by the intercalation of dodecylamine. A systematic expansion of the interlayer space was observed by the ion exchange with a series of alkyltrimethylammonium ions to show the variation of the layer charge density.
authors.affiliation: Graduate School of Creative Science and Engineering, Waseda University, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Nakamura
authors.forename: Makoto
authors.initials: M
authors.lastname: Ogawa