Intercalation of tartrazine into ZnAl and MgAl layered double hydroxides

The intercalates of Tartrazine Acid Yellow were prepared by heating [Zn0.67Al0.33(OH)(2)]( CO3)(0.165) center dot 0.5H(2)O or [Mg0.70Al0.30(OH)(2)](CO3)(0.15) center dot 0.5H(2)O with a solution of an acid form of Tartrazine in an open reaction vessel or by stirring the powdered calcined hydrotalcites with a Tartrazine solution at room temperature. The intercalates were characterized by chemical and thermal analysis, X-ray powder diffraction and UV-VIS spectroscopy. The intercalates prepared by stirring the calcined host powders have worse crystallinity than those prepared by ion exchange. A possible arrangement of the Tartrazine anions in the intercalates was suggested on the basis of their chemical compositions and interlayer distances, taking into account van der Waals dimensions of the guest anions and assuming that the structure of the host layers is not changed during the intercalation process.