Acidity and porosity modulation of MWW type zeolites for Nopol production by Prins condensation

Prins condensation of β-pinene with paraformaldehyde was carried out over MCM-22, delaminated ITQ-2 and silica pillared MCM-36. The mesopore-containing MCM-36 and ITQ-2 catalysts exhibit higher conversion of β-pinene due to more exposed acid sites. Lewis acid sites are responsible for Prins condensation while Brønsted acid sites favor the isomerization of pinene. The Brønsted acid sites can be removed mostly by ion-exchanging the zeolites with sodium cations. Thus, NaMWW zeolites had a higher selectivity towards Nopol. Of these, NaITQ-2 showed the highest activity and selectivity, and is a stable and reusable catalyst for production of Nopol.

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► The accessibility of acid sites is essential in the condensation reaction.
► Lewis acid sites are responsible for condensation while Brønsted acid sites favor isomerization.
► Brønsted acid sites on zeolites can be removed by ion-exchanging with sodium cations.
► NaITQ-2 is a good catalyst to produce Nopol by Prins condensation.