Cyclization of Pseudoionone into α-Ionone Over Heteropolyacid Supported on Mesoporous Silica SBA-15

Cyclization of pseudoionone into alpha-ionone was performed over the series heteropolyacid supported on SBA-15 in liquid-phase at 363 and 373 K using a batch reactor. It has been demonstrated that the liquid-phase synthesis of alpha-ionone by pseudoionone cyclization can be efficiently achieved on heteropolyacid/SBA-15 materials. The high catalytic performance of PW12/SBA-15 materials is due to their strong Bronsted acidity, high dispersion of active phase and also to absence of steric constraints for pseudoionone cyclization. PW12/SBA-15 catalysts are specially active and selective for this reaction giving predominantly alpha-ionone, as the main product, with high yield (about 60% at 373 K after 2 h) close to that obtained via the homogeneous synthesis. This catalytic system is more active and efficient in comparison with heteropolyacid supported on commercial silica. In order to achieve comparable amount of alpha-ionone, as is got for PW12/SBA-15, belongs to apply five times more of the catalyst based on classical SiO2.