| Summary: | This contribution concerns the effect of the chemical composition of the brucite-type layer of bi-cationic LDH materials Zn<sub>x</sub>Al and Mg<sub>x</sub>Al (x = 2–5) and tri-cationic LDH Mg<sub>y</sub>Zn<sub>z</sub>Al (y + z = 4, y = 1, 2, 3) on their catalytic activity for olefin epoxidation with H<sub>2</sub>O<sub>2</sub> in the presence of acetonitrile. LDH materials were prepared by the standard method of co-precipitation at constant pH 10, using an aqueous solution of the corresponding metal nitrates and a basic solution containing NaOH and Na<sub>2</sub>CO<sub>3</sub>. The fresh LDHs were calcined to yield the corresponding mixed oxides and then the recovery of the LDH structure by hydration of the mixed oxides was performed. The resulting samples were characterized by AAS, XRD, DRIFT, DR-UV–Vis, BET and determination of basic sites. The results of the catalytic tests for olefin epoxidation were well correlated with the basicity of the samples, which was in turn related to the M<sup>2+</sup>/Al<sup>3+</sup> ratio and the electronegativity of different bivalent metals in the brucite-type layer.
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