Zr-Beta Zeolite: Synthesis Strategies, Physicochemical Properties, and Catalytic Applications (A Review)

Methods for the synthesis, approaches to the physicochemical characterization of acid properties, and catalytic activity of Zr-containing zeolite Beta (Zr-Beta) are reviewed. Direct and postsynthetic approaches to the incorporation of zirconium into the zeolite framework are considered, including liquid-phase incorporation using various solvents, mechanochemical incorporation, and recrystallization. The relationship between the method of zirconium incorporation and the physicochemical properties of the resulting materials, including the pore structure, concentration of defects, and structure of zirconium acid sites, is analyzed. The effect of the type and local environment of Zr-Beta acid sites on its catalytic activity in Diels–Alder [2+4]-cycloaddition, aldol and croton condensations, Meerwein–Ponndorf–Verley–Oppenauer reduction of aldehydes and ketones, epoxide ring opening, and cascade biomass transformations is considered. The catalytic properties of Zr-Beta are shown to be determined by a combination of material characteristics, including the zirconium content and local environment, ratio of open to closed acid sites, concentration of defects, and pore structure.