CO₂ Cycloaddition of Epichlorohydrin over NH₂‐Functionalized MIL‐101

Abstract

CO 2 is the major greenhouse gas suspected to cause global warming, and various CO 2 capture and sequestration technologies using liquid amines or solid-phase sorbents to remedy the situation have been evaluated. [1][2][3] Chemical conversion of CO 2 is also being considered as a means of sequestration, because CO 2 can be an attractive C 1 building block that can be converted to valuable chemical products. In this regard, the cycloaddition reaction is one of the most promising reactions for CO 2 currently under consideration. In this process, cyclic carbonates are produced by the coupling of carbon dioxide with various epoxides. [4][5][6] These carbonates are used widely in industry as solvents, monomers, and pharmaceutical and fine-chemical intermediates. 7 A range of homogeneous catalysts, such as ionic liquids, or transition-metal complexes, such as Re(CO) 5 Br or Co(III)-salen, [8][9][10] have been used to produce cyclic carbonates. On the other hand, the frequent necessity to employ a base promoter and the rigorous purification process required for catalyst separation are significant limitations. A heterogeneous catalyst that can promote the reaction under mild reaction conditions would be highly desirable.Metal-organic frameworks (MOFs) are crystalline organicinorganic hybrid structures formed by the coordination of metal ions or clusters with multidentate organic linkers. These materials have been investigated actively for potential energy storage, CO 2 capture, hydrocarbon adsorption/separation, and catalysis owing to their high surface areas in uniformly sized pores as well as the high metal content in high dispersion. 11-14Song et al. examined the cycloaddition of CO 2 to propylene epoxide over MOF-5 with a quaternary ammonium salt as a co-catalyst, 15 whereas ZIF-8 and Cu 3 (BTC) 2 were tested for the cycloaddition of epichlorohydrin (ECH) without employing a solvent. 16,17 Mg-MOF-74 was effective not only for CO 2 capture but also for its chemical conversion via a cycloaddition reaction.18 Recently, amine-functionalized was reported to be promising for the cycloaddition of styrene oxide with CO 2 , and the catalytic activity was correlated with the concerted contribution by Lewis acid/base sites on the MOF catalysts. MIL-101 is a chromium-benzenedicarboxylate MOF having a high surface area with excellent stability against moisture and other chemicals, and has been applied to a wide range of chemical reactions either as a catalyst or as support material. [20][21][22] In this study, the amine-functionalized MIL-101 structures were prepared by two different routes: direct solvothermal method using 2-aminobenzene-1,4-dicarboxylate as a ligand, and post-synthesis grafting of diethylenetriamine (DETA) onto the Cr open metal sites. The materials were studied as a catalyst for the cycloaddition of CO 2 to ECH. The amine-functionalized MIL-101 structures were found to be active catalysts for the catalytic cycloaddition of CO 2 to a range of epoxides in an organic solvent, and control of the relative amounts ...

Zeolite-Like Metal Organic Framework (ZMOF) with a rho Topology for a CO2 Cycloaddition to Epoxides

“…rho-ZMOF showed a higher BET surface area and pore volume (871 m 2 /g, 0.37 cm 3 /g) than those of sod-ZMOF (352 m 2 /g, 0.14 cm 3 /g), which was a consequence of the imidazole ligands in sod -ZMOF protruding into the pore space. 30 The thermal stability of the ZMOF samples was examined by TGA, as shown in Figure 2d. Both exhibited two major weight losses within the heating range.…”

“…The corresponding textural properties of the prepared samples are listed in Table . rho -ZMOF showed a higher BET surface area and pore volume (871 m 2 /g, 0.37 cm 3 /g) than those of sod -ZMOF (352 m 2 /g, 0.14 cm 3 /g), which was a consequence of the imidazole ligands in sod -ZMOF protruding into the pore space . The thermal stability of the ZMOF samples was examined by TGA, as shown in Figure d.…”

Chemoselective Transfer Hydrogenation of Flavoring Unsaturated Carbonyl Compounds over Zr and Hf‐based Metal–Organic Frameworks

“…Isomorphous substituted “Zr” in the framework of zeolite Beta (Zr‐Beta) with only a small amount of Zr, achieved 96% cinnamyl alcohol yield from cinnamaldehyde 20 . In recent years, MOFs and MOF‐derived materials have been used successfully as heterogeneous catalysts in several chemical transformations 21–24 . Consequently, Zr‐containing MOFs have recently been tested for CTH of various carbonyl compounds 25–27 .…”

“…20 In recent years, MOFs and MOFderived materials have been used successfully as heterogeneous catalysts in several chemical transformations. [21][22][23][24] Consequently, Zr-containing MOFs have recently been tested for CTH of various carbonyl compounds. [25][26][27] Our research group has also contributed to the successful transformation of various biomass-derived carbonyl compounds using series of Zr-based functional and metal node-modified MOFs under mild reaction conditions.…”

Self-Assembly in Polyoxometalate and Metal Coordination-Based Systems: Synthetic Approaches and Developments

“…Catalysis is one of the most studied area of applications for MOF-based materials [78][79][80]. The porous nature of MOF structures allows the efficient diffusion of the substrates towards the catalytic sites ( Figure 13).…”