552-86-3Relevant articles and documents
Recyclable Supported Carbene Catalysts for High-Yielding Self-Condensation of Furaldehydes into C10 and C12 Furoins
Wang, Lu,Chen, Eugene Y.-X.
, p. 6907 - 6917 (2015)
Two highly efficient and recyclable heterogeneous azolium catalyst systems, one grafted (g) onto the inorganic oxide (Silica) and the other onto the organic polymer [Merrifield's peptide or chloromethylated polystyrene (PS) resin], have been developed and employed to catalyze quantitative self-coupling (umpolung condensation) reactions of furfural and 5-hydroxymethylfurfural (HMF) into C10 and C12 furoins, respectively. Supported benzimidazolium ([BI]) salts bearing a long-chain alkyl substituent (i.e.; C12 dodecyl) on the azolium nitrogen atom, upon activation with a suitable base to generate the corresponding N-heterocyclic carbene (NHC) catalyst, are found to be far more effective catalysts for furaldehyde self-coupling reactions than the analogous catalysts carrying a short-chain alkyl substituent (i.e.; C1 methyl). Thus, supported NHC catalysts generated in situ from Silica-g-[BI]-C12 or PS-g-[BI]-C12-benzyl/base afford the C10 and C12 furoins in about 97% and 94% yield, respectively. By adopting a catalyst recycling procedure that involves activation of the precatalyst with a base to generate the NHC catalyst, catalysis in conversion of furaldehydes into furoins, and recycle of the catalyst by quenching the reaction with HCl to convert the catalyst back to the precatalyst, excellent recyclability has been achieved without loss of the catalytic activity after 10 cycles by maintaining essentially a constant furoin yield of 96-97% for all 10 cycles performed with both supported catalyst systems.
Hybrid catalysts based on N-heterocyclic carbene anchored on hierarchical zeolites
Gianotti, Enrica,Miletto, Ivana,Ivaldi, Chiara,Paul, Geo,Marchese, Leonardo,Meazza, Marta,Rios, Ramon,Raja, Robert
, p. 35336 - 35344 (2019)
Hybrid materials have been synthesized by anchoring a N-heterocyclic carbene (NHC) precursor on different inorganic zeolitic supports with hierarchical porosity, in particular hierarchical HZSM-5 and SAPO-5. Hierarchical porous inorganic supports have been obtained both by top-down and bottom-up approaches and the role of hierarchical porosity has been evaluated. A detailed physico-chemical characterization has been performed on the organic-inorganic hybrids using a multi-technique approach (XRD, volumetric and thermogravimetric analysis, ssNMR and FTIR) in order to establish a structure-property relationship. The hybrids were tested in the benzoin condensation reaction of furfural, a base catalyzed reaction.
N-PEGylated Thiazolium Salt: A Green and Reusable Homogenous Organocatalyst for the Synthesis of Benzoins and Acyloins
Haghighi, Ali Javaheri,Mokhtari, Javad,Karimian, Khashayar
, p. 1646 - 1652 (2020/10/19)
N-PEGylated-thiazolium salt is used as efficient catalyst for the benzoin condensation. The catalyst was synthesized by reaction of activated polyethylene glycol 10,000 (PEG-10000) with 4-methyl-5-thiazoleethanol (sulfurol). Reaction mixture undergoes temperature-assisted phase transition and catalyst separated by simple filtration. After reaction course, catalyst can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. Synthesized benzoins and acyloins by this method have been characterized on the basis of melting point and 1H-NMR spectral studies. Graphic Abstract: [Figure not available: see fulltext.]
Sol-gel synthesis of ceria-zirconia-based high-entropy oxides as high-promotion catalysts for the synthesis of 1,2-diketones from aldehyde
Dinjar, Kristijan,Djerdj, Igor,Koj?inovi?, Jelena,Kukovecz, ákos,Markovi?, Berislav,Mileti?, Aleksandar,Nagy, Sándor Balázs,Sapi, Andras,Stenzel, David,Széchenyi, Aleksandar,Szenti, Imre,Tang, Yushu,Tatar, Dalibor,Varga, Gábor,Ziegenheim, Szilveszter
, (2021/10/20)
Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.
