1. The acid-catalysed reaction of α-pinene over molybdophosphoric acid immobilised in dense polymeric membranes
- Author
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Castanheiro, J.E., Ramos, A.M., Fonseca, I., and Vital, J.
- Subjects
- *
CATALYSTS , *SILOXANES , *ZEOLITES - Abstract
The α-pinene hydration to α-terpineol was studied using as catalysts polymeric catalytic membranes consisting of HPMo entrapped in polyvinyl alcohol (PVA) cross-linked with 10, 20 and 30% of succinic acid, and HPMo encaged in USY zeolites dispersed in a polydimethylsiloxane (PDMS) matrix.In the case of HPMo/PVA membranes it was observed that membrane activity increases with the polymer cross-linking, due to the increase in membrane hydrophobicity, up to the limit of the increasingly restrictions to the molecules mobility. The HPMo-USY/PDMS membrane shows a significantly higher activity for pinene hydration, which is even higher than that observed with USY encaged HPMo alone. However, selectivity to α-terpineol (65% at 80% conversion) is slightly lower than that obtained for the HPMo/PVA cross-linked with 20 or 30% of succinic acid (70–75% at 90% conversion).For both catalytic membranes, HPMo/PVA or HPMo-USY/PDMS, the stability is reasonable good and catalyst activity increases in the subsequent uses of the same membrane, probably due to the interaction between retained α-terpineol and the polymer matrix. [Copyright &y& Elsevier]
- Published
- 2003
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