1. Synthesis of Florol via Prins cyclization over heterogeneous catalysts.
- Author
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Lasne, Basile, Mäki-Arvela, Päivi, Aho, Atte, Vajglova, Zuzana, Eränen, Kari, Kumar, Narendra, Sánchez-Velandia, Julián E., Peurla, Markus, Mondelli, Cecilia, Pérez-Ramírez, Javier, and Murzin, Dmitry Yu
- Subjects
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HETEROGENEOUS catalysts , *RING formation (Chemistry) , *BRONSTED acids , *CATALYST testing , *INDUSTRIAL goods , *ZEOLITES - Abstract
[Display omitted] • Prins cyclisation from isovaleraldehyde and isoprenol to tetrahydropyranol. • Zeolites with varying acidity and hierarchical materials as catalysts. • H-Beta-300 zeolite giving 72% selectivity to the desired product at 99% conversion. • The cis/trans ratio of tetrahydropyranols depends on porous structure. • Parallel formation of tetrahydropyranol and dihydropyran confirmed by DFT. In this work, several heterogeneous micro- and mesoporous, acidic catalysts were tested for the selective synthesis of Florol®, an industrial product formed via condensation and rehydration starting from isoprenol and isovaleraldehyde in dimethylcarbonate as a solvent. The results showed that a mildly acidic, microporous H-Beta-300 with SiO 2 /Al 2 O 3 ratio of 300 was the best catalyst, giving 72% selectivity with 99% conversion at 40 °C when using the molar ratio isoprenol to isovaleraldehyde of 1:5. More acidic zeolites gave slightly lower selectivity, while the lowest selectivity (up to 52%) was obtained with mesoporous catalysts exhibiting mild acidity and no strong Brønsted acid sites. Selectivity to pyranols was nearly constant when changing temperature, while a larger excess of isovaleraldehyde promoted formation of tetrahydropyranol. H-Beta-300 catalyst was successfully after calcination at 400 °C. DFT calculations pointed out on the parallel formation of tetrahydro pyranols and dihydropyrans, which are the corresponding dehydration products. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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