Evaluation of Fe- and Cr-containing clinoptilolite catalysts for the production of camphene from α-pinene

The catalytic properties of the Cr3+- and Fe3+-loaded clinoptilolites were screened in the liquid-phase isomerization of α-pinene and the major products were found to be camphene and limonene. Selectivity to camphene was superior for the 0.7Fe-CL catalyst than those observed for the Raw-CL and 0.4Cr-CL catalyst. Over raw clinoptilolite, the proportion of limonene and other isomers reached ∼65% while it was ∼15% with 0.7Fe-CL and ∼56% with 0.4Cr-CL. The results also show that the selectivity to camphene increases with increasing reaction time reaching up to about ∼72% at 428 K over 0.7Fe-CL catalyst.