A template approach for the multifunctionalization of the interlayer space of kaolinite

Abstract The interlayer space of kaolinite was functionalized with an ionic liquid (1-(2-hydroxyethyl)-3-methylimidazolium chloride (IL1)) by controlling the amount of grafted organic cation. The strategy used was to co-intercalate the compound to be grafted and a non-reactive template. The template was an IL (1-(propyl)-3-methylimidazolium chloride (IL2)) capable of intercalating in the interlayer space of kaolinite, without being grafted. This template when intercalated covers certain grafting sites and prevents them from reaction with other chemical species present in the interlayer space. Physicochemical characterizations confirm that the presence of the template effectively reduces the amount of grafted IL. This phenomenon was observed through the decrease of the d001-value of the nanohybrid kaolinite (from 13.1 A to 9.6 A) and the increase of the amount of physisorbed water which occupies the vacant space resulting from the partial grafting of the IL. Multifunctional materials were prepared by intercalating dimethyl sulfoxide (DMSO) or by grafting triethanolamine (TEA) molecules in the vacant space, using simple synthesis procedures. Several multifunctional materials can be produced using this approach, the main caution being the judicious choice of reagents. These materials can find promising applications in catalysis and in molecular recognition systems.