Preparation and characterization of Mg-Al layered double hydroxides intercalated with benzenesulfonate and benzenedisulfonate

Mg-Al layered double hydroxides (Mg-Al LDHs) intercalated with benzenesulfonate (BS^-) and benzenedisulfonate (BDS^2-) ions were prepared by coprecipitation and characterized by X-ray diffraction, FT-IR spectroscopy, and chemical analyses. The intercalated BS^- and BDS^2- maintained their intrinsic molecular structures within the Mg-Al LDH interlayers. At low intercalation levels, the benzene ring of BS^- in BS · Mg-Al LDH was inclined at 30° relative to the plane of the brucite-like layers of Mg-Al LDH. With increasing BS^- content, the benzene ring adopted an additional configuration perpendicular to the Mg-Al LDH layers. In BDS-intercalated Mg-Al LDH, the benzene ring of BDS^2- was tilted at 26° relative to the plane of the Mg-Al LDH layers. Intercalation levels of BDS^2- were smaller than those of BS^- despite the greater charge density of BDS^2-, which was likely attributable to a greater degree of electrostatic repulsion between intercalated anions.