Effect of iron content on selectivity in isomerization of α-pinene oxide to campholenic aldehyde over Fe-MMM-2 and Fe-VSB-5

Isomerization of alpha -pinene oxide to campholenic aldehyde (CA) was investigated over Fe-containing mesoporous mesophase materials (Fe-MMM-2) and microporous nickel phosphate molecular sieves (Fe-VSB-5). Activity and selectivity of reaction towards CA over Fe-containing materials was found to depend on iron content in materials that affects oligomeric state of Fe and amount of Lewis acid sites. In the presence of Fe-VSB-5 selectivity towards CA increased with increase in iron content in structure, while that decreased in the presence of Fe-MMM-2. This phenomenon is related to change in agglomeration of iron species in Fe-MMM-2 structure. The high selectivity towards CA in the presence of Fe-VSB-5 was suggested to arise from unique structure of these materials, which favours shape selectivity.