Intercalation compounds of Mg-Al layered double hydroxides with dichlophenac: different methods of preparation and physico-chemical characterization

[2-(2,6-Dichloro-phenylamino)-phenyl]-acetic acid (DPAPAc) was intercalated between layers of Mg-Al hydrotalcites. Several methods of incorporation were applied: direct ion exchange of the layered double hydroxide (LDH) carbonates with the organic ions, direct synthesis by co-precipitation of metal nitrates and sodium DPAPAc, and reconstruction of the Mg-Al oxide solid solution. The LDH reconstruction method led to the highest degree of intercalation and gave rise to an enlargement of the interlayer space of about 6.7 Angstrom, which was observed in the powder X-ray diffraction (PXRD) patterns. The new hybrid phase obtained by this method was partially intercalated, as the LDH-carbonate phase was still mainly present in the material. The characterization of the prepared samples was also achieved with X-ray photoelectron spectroscopy (XPS), which indicated changes in the environment of the elements on insertion of the organic anions. Finally, the collected data indicated that the method of reconstruction was the most effective route to the hybrid materials. (C) 2004 Elsevier B.V. All rights reserved.