Novel reactive amino-compound: Tris(hydroxymethyl)aminomethane covalently grafted on kaolinite

A novel reactive solid containing amine groups was prepared by functionalization of the Brazilian São Simão kaolinite with tris(hydroxymethyl)aminomethane, designated TRIS. The functionalization involved refluxing of the molten TRIS in the presence of kaolinite previously intercalated with dimethylsulfoxide (DMSO). TRIS effectively displaced DMSO from the clay mineral interlayer, giving rise to Al–O–C bonds, thereby forming a hybrid organic–inorganic matrix. The resulting material was characterized by X-ray diffraction, thermal analysis, infrared absorption spectroscopy, and C and N elemental analysis. The X-ray diffractograms revealed the intercalation of DMSO, and subsequently TRIS. The thermogravimetric curves of the kaolinite samples functionalized with TRIS indicated that the materials were thermally stable up to 250 °C. Displacement of the bands due to interlayer hydroxyl groups in the infrared absorption spectra and the presence of vibration bands due to NH2 groups at 3349, 3331, 3290, and 1589 cm− 1 also confirmed functionalization of the kaolinite with TRIS.