Prins cyclization in 4-methyl-2-phenyl-tetrahydro-2H-pyran-4-ol preparation using smectite clay as catalyst
| Autor: | Eliška Vyskočilová, Mariya Shamzhy, Eva Vrbková, Jiří Krupka, Anna Gruberová, Libor Červený |
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| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Prins reaction Isoprenol 010402 general chemistry 01 natural sciences Aldehyde Catalysis 0104 chemical sciences Reaction rate Benzaldehyde chemistry.chemical_compound chemistry Organic chemistry Methanol Physical and Theoretical Chemistry Selectivity |
| Zdroj: | Reaction Kinetics, Mechanisms and Catalysis. 124:711-725 |
| ISSN: | 1878-5204 1878-5190 |
| DOI: | 10.1007/s11144-018-1371-7 |
| Popis: | Prins cyclization of isoprenol with benzaldehyde as a model aldehyde was performed using montmorillonite K10 as an acid catalyst. Various reaction conditions were used including catalyst modification by mineral acids and calcination. Both treatments influenced the selectivity to substituted tetrahydropyranol negatively. Due to the increased specific surface of the catalyst the reaction rate increased. Both addition of water and methanol to the reaction mixture prevented dehydration but the selectivity to desired product remained the same. Chosen reaction conditions (70 °C, ratio aldehyde:isoprenol 0.9:1, catalyst amount 110 wt%, solvent toluene) were used in Prins cyclization of other aldehydes with the similar results. Montmorillonite K10 may be used in preparation of substituted tetrahydropyranols with selectivity ranging from 59 to 69% (depending on aldehyde), which is comparable with or higher than heterogeneous catalysts used previously. This catalyst may be also used repeatedly with slight decrease in the reaction rate and no loss of selectivity. |
| Databáze: | OpenAIRE |
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