5660-60-6Relevant articles and documents
AlPO4 and AlPO4-Al2O3 as Heterogeneous Catalysts in the Preparation of 1,3-dioxolanes by Acetalization of Different Carbonyl Compounds
Bautista, F. M.,Campelo, J. M.,Garcia, A.,Leon, J.,Luna, D.,Marinas, J. M.
, p. 620 - 622 (1994)
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Inhibition by Water during Heterogeneous Br?nsted Acid Catalysis by Three-Dimensional Crystalline Organic Salts
Belokon, Yuri N.,Gak, Alexander,Khakina, Ekaterina,Khrustalev, Victor N.,Korlyukov, Alexander A.,Kuznetsova, Svetlana,Li, Han,Lobanov, Nikolai,Nelyubina, Yulia,North, Michael,Peregudov, Alexander S.,Riazanov, Vladimir,Zhereb, Vladimir
, p. 6364 - 6372 (2021/10/20)
A new self-assembled and self-healing class of metal free, recyclable, heterogeneous Br?nsted acid catalysts has been developed by the protonation of aniline derivatives (tetrakis(4-aminophenyl)methane, leuco-crystal violet, benzidine, and p-phenylenediamine) with aromatic sulfonic acids (tetrakis(phenyl-4-sulfonic acid)methane, and 2,6-naphthalenedisulfonic acid). As a result, five three-dimensional crystalline organic salts (F-1a, F-1b, F-1c, F-2, and F-3) were obtained, linked by hydrogen bonds and additionally stabilized by the opposite charges of the components. Frameworks F-2 and F-3 were prepared for the first time and characterized by elemental analysis, X-ray structural analysis (for F-2), thermogravimetry, SEM, and FTIR spectroscopy. The catalytic activities of crystalline organic salts F-1-3 have been explored in industrially important epoxide ring-opening and acetal formation reactions. The presence of encapsulated water inside frameworks F-1a and F-2 had an inhibitory effect on the performance of the catalysts. X-ray diffraction analysis of hydrated and dehydrated samples of F-1a and F-2 indicated that water of crystallization served as a cross-linking agent, diminishing the substrate induced "breathing"affinities of the frameworks.
Acid properties of organosiliceous hybrid materials based on pendant (fluoro)aryl-sulfonic groups through a spectroscopic study with probe molecules
Erigoni, Andrea,Paul, Geo,Meazza, Marta,Hernández-Soto, María Consuelo,Miletto, Ivana,Rios, Ramon,Segarra, Candela,Marchese, Leonardo,Raja, Robert,Rey, Fernando,Gianotti, Enrica,Díaz, Urbano
, p. 6308 - 6317 (2019/11/20)
Two different heterogeneous catalysts carrying aryl-sulfonic moieties, in which the aromatic ring was either fluorinated or not, were successfully synthesized. The multi-step synthetic approaches implemented involved the synthesis of the silyl-derivative, template-free one-pot co-condensation (at low temperature and neutral pH) and tethering reaction. A multi-technique approach was implemented to characterize the hybrid organic-inorganic catalysts involving TGA, N2 physisorption analysis, FTIR spectroscopy, and ss MAS NMR (1H, 13C, 29Si) spectroscopy. Specifically, the acidity of the organosiliceous hybrid materials was studied through the adsorption of probe molecules (i.e. CO at 77 K and NH3 and TMPO at room temperature) and a combination of FTIR and ss MAS NMR spectroscopy. The catalytic activity of the two hybrids was tested in the acetal formation reaction between benzaldehyde and ethylene glycol. Preliminary results indicated superior performances for the fluoro-aryl-sulfonic acid, compared to the non-fluorinated sample. The findings hereby reported open new avenues for the design of heterogeneous sulfonic acids with superior reactivity in acid-catalyzed reactions. Moreover, through the implementation of spectroscopic studies, using probe molecules, it was possible to investigate in detail the acidic properties of hybrid organosiliceous materials.