Synthesis and Characterization of [NaO3SOCH2CH2OSO3Na] and Its Anchored Form: Surface-Grafted Acid Groups on Zirconium Hydroxide

Abstract

A disodium 1,2-ethanediol bis(hydrogen sulfate) salt, [NaO3SOCH2CH2OSO3Na], has been synthesized and anchored onto zirconium hydroxide to produce a high concentration of solid dual acid sites. The reaction of HCON(CH3)2·SO3, (CH2OH)2, and NaOH produced a stable [NaO3SOCH2CH2OSO3Na] precursor in 40% yield. The [NaO3SOCH2CH2OSO3Na] salt was exchanged with NH4+ using an NH4−R resin followed by impregnation of a zirconium hydroxide slurry, yielding [−O3SOCH2CH2OSO3−]2- anchored on Zr(OH)4. The characterization of the samples included high-resolution X-ray photoelectron, near-infrared diffuse reflectance, 1H NMR, and 13C magic angle spinning NMR spectroscopies. The results provided evidence of a μ2-CH2CH2− ligand bridged between two −OSO3− groups in the precursor and the anchored precursor. The ethyl bridge was removed upon calcination at 500 °C to yield surface-grafted acid groups on zirconia. This material had a surface area of 97 m2 g-1 and an acid-exchange capacity of 0.70 mequiv of H+/g, corresponding to ...