No abstract

No abstract

No abstract

Ionone synthesis (a, b and c isomers) by pseudoionone cyclization was studied on zeolite HBEA, Amberlyst 35W, SiO 2 -Al 2 O 3 , and unsupported and silicasupported heteropolyacids (HPA/SiO 2 ). Ionone formation was preferentially promoted on strong Brønsted acid sites. A 79% ionone yield was obtained on 58.5 wt.% HPA/SiO 2 after 1.5 h of reaction at 383 K and 250 kPa. This value is similar to the best yields reported for the homogeneouslycatalyzed reaction using sulfuric acid.