Ammonium Salts Catalyzed Acetalization Reactions in Green Ethereal Solvents
| Autor: | Sebastiano Garroni, Martina Corrias, Lidia De Luca, Silvia Gaspa, Riccardo Polese, G. Satta, Rosella Crisafulli, Ugo Azzena, Luigi Urtis, Salvatore Pintus, Massimo Carraro, Luisa Pisano, Luca Nuvoli, Michela Sanna, Nina Senes |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
ammonium salts Cyclopentyl methyl ether characterization of heterogeneous catalysts lcsh:Chemical technology Heterogeneous catalysis Toluene acetals Catalysis lcsh:Chemistry chemistry.chemical_compound heterogeneous catalysis lcsh:QD1-999 chemistry Azeotrope Organic chemistry lcsh:TP1-1185 Ammonium Physical and Theoretical Chemistry Chemoselectivity Counterion green solvents |
| Zdroj: | Catalysts Volume 10 Issue 10 Catalysts, Vol 10, Iss 1108, p 1108 (2020) |
| ISSN: | 2073-4344 |
| DOI: | 10.3390/catal10101108 |
| Popis: | Cyclopentyl methyl ether and 2-methyltetrahydrofuran, low impact ethereal solvents forming a positive azeotrope with water, were successfully employed as solvents in the synthesis of a variety of acetals carried out under Dean&ndash Stark conditions in the presence of heterogeneous acidic catalysts. Under these conditions, ammonium salts, either as such or supported on SiO2, performed better or equally well than widely employed homogeneous and heterogeneous acidic catalysts such as p-toluenesulfonic acid, Amberlyst 15® or Montmorillonite K10. Several examples highlight the advantage of tuning the relative acidities of ammonium salts by appropriately selecting the counterion. Within one of these examples, our protocol clearly outweighs the classic p-toluenesulfonic acid/toluene protocol in terms of chemoselectivity. Silica-supported catalysts were characterized by SEM, TEM, and FTIR spectroscopies, as well as by N2 physisorption. Such a characterization reveals an even distribution of ammonium salts on silica, thus confirming the formation of expected catalytic supports. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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