A mini-review on solid superbase catalysts developed in the past two decades

Abstract

In this mini-review, we focus on the research activities on solid superbase catalysts that have been conducted in the past two decades. We summarize the type and preparation of superbases, the mechanism for the generation of basic sites, and the applications of superbases in catalysis. It is pointed out that several kinds of superbases are reported so far with the majority of solid superbases generated using a single metal oxide as support. However, the superbases are extremely sensitive to water and CO 2 , and rigorous conditions are required for their preparation and utilization. As a consequence, the development and application of solid superbases is limited. Despite the understanding of formation mechanism of superbasic sites being essential for the design of solid superbases, reports on this aspect are scant. It is envisaged that composite metal oxides and porous materials should be developed as support materials to generate novel solid superbases, and our recent research results open up a new route for the design and synthesis of composite oxide superbase materials. Efforts should be devoted to study the generation of superbase sites by adopting advanced techniques for characterization and new methods for theoretical investigation. Moreover, it is predicted that solid superbases will find new applications in catalysis, especially in reactions that require high temperatures for desorption of acidic substances from surfaces of superbases.

Transfer hydrogenation over sodium-modified ceria: Enrichment of redox sites active for alcohol dehydrogenation

“…The shift signifies, on average, a more electron-rich environment of lattice oxygens. Since sodium is present it would seem plausible that the apparent increased oxygen electron density for Ce-Na could be due to higher material basicity, which has been observed for other metal oxides modified with sodium [74,75] and could explain the different reaction rates observed. However, the basic properties and C-H activating ability [76] of the two materials were found to be identical by testing with basicity probes and base-catalyzed reactions (Fig.…”

Design and fabrication of mesoporous heterogeneous basic catalysts

“…Her current research interests focus on design, synthesis, and applications of porous functional materials, with emphasis on adsorbents and catalysts. [14][15][16][17] A well-known application of the solid base is the synthesis of 4-methylthiazole, which is an intermediate in the preparation of a systemic fungicide thiabendazole. Taking account of the strong tendency of Na to donate electrons, it is easy to understand that Al 2 O 3supported Na acts as an effective basic catalyst.…”

“…K 3 PO 4 ) 13 with different pore structures including micropores, mesopores, and macropores. [14][15][16][17] A well-known application of the solid base is the synthesis of 4-methylthiazole, which is an intermediate in the preparation of a systemic fungicide thiabendazole. 18 The traditional synthetic route towards 4-methylthiazole consists of five steps that involve several hazardous chemicals (see eqn (1)-( 5) in Scheme 1).…”

Synthesis and Antioxidant Activity of Prenylated Resveratrol

“…Therefore, Synthesis of monomeric resveratrol derivatives has been a challenging topic in both organic and medicinal chemistry. In recent years, a number of catalytic methods have been developed to generate chemical diversity synthetically 16,17 . Prenylation plays a major role in the diversification of aromatic natural products, such as phenylpropanoids, flavonoids, and coumarins 18 .…”