PREPARATION AND CHARACTERIZATION OF 2 DISTINCT ETHYLENE-GLYCOL DERIVATIVES OF KAOLINITE

A new, well-ordered, thermally robust ethylene glycol intercalate of k aolinite was formed by refluxing the dimethyl sulfoxide intercalate of kaolinite (Kao-DMSO) with dry ethylene glycol (EG). This new phase (K ao-EG 9.4 angstrom) which is characterized by a d001 of 9.4 angstrom i s distinct from a previously reported ethylene glycol intercalated pha se of kaolinite (Kao-EG 10.8 angstrom) which has a d001 of 10.8 angstr om. The characterization of these two phases was studied by XRD, NMR, FTIR, and TGA/DSC. It was found that the concentration of water in the ethylene glycol reaction media played a crucial role in governing whi ch of the phases predominated. Water favored Kao-EG 10.8 angstrom form ation, while anhydrous conditions favored the formation of Kao-EG 9.4 angstrom. It is hypothesized that Kao-EG 9.4 angstrom is a grafted pha se resulting from the product of the condensation reaction between an aluminol group on the interlamellar surface of kaolinite and the alcoh ol group of ethylene glycol. Ethylene glycol units would be attached t o the interlamellar surface of kaolinite via Al-O-C bonds. The Kao-EG 9.4 angstrom phase was found to be resistant to both thermal decomposi tion up to 330-degrees-C and also, once formed, in the absence of inte rlamellar water molecules, to decomposition by hydrolysis in refluxing water.