Selective oxidation of styrene over Mg–Co–Al hydrotalcite like-catalysts using air as oxidant
•The successful substitution of Mg2 + by Co2 + in Mg/Al hydrotalcite•Co2 + in hydrotalcite is essential for the epoxidation of styrene.•A good activity in the styrene oxidation under mild condition•A higher selectivity to epoxide styrene over the cobalt-richer hydrotalcite
A set of synthesized Mg/Co/Al hydrotalcites was synthesized and characterized by XRD, XPS, BET, SEM, TEM, and FT-IR physical techniques. The partial substitution of Mg2 + by Co2 + in brucite layers has not significantly affected the layered double hydroxide structure, but plays a crucial role in the oxidation of styrene in the presence of air. The prepared Mg/Co/Al hydrotalcite-like compounds express a good activity and stability in the oxidation of styrene in the free-solvent condition. Both styrene conversion and desired product selectivities are strongly dependent on the cobalt substitution content. The intra-hydrotalcite lattice Co2 + ions are active sites for the epoxidation of styrene.
Graphical abstractA strong correlation between catalytic activity in the oxidation of styrene and Co2 + in brucite-like layers of layered double hydroxides (other products: phenyl acetaldehyde, benzoic acid, styrene glycol, benzyl benzoate, and polymerized products).Figure optionsDownload full-size imageDownload as PowerPoint slide
Journal: Catalysis Communications - Volume 45, 5 February 2014, Pages 153–157