Synthesis of campholenic aldehyde from α-pinene using bi-functional PrAlPO-5 molecular sieves

Abstract

Praseodymium incorporated AlPO-5 was synthesized hydrothermally in fluoride medium using triethylamine as template. PrAlPO-5 could be bi-functional in nature since the isolated praseodymium sites acted both as redox and acid sites. The framework incorporation of praseodymium in AlPO-5, and the absence of separate praseodymium oxide phase were confirmed by laser Raman and fluorescence studies. The chemisorbed oxygen on praseodymium sites were identified by ESR. The ex-situ pyridine adsorbed IR spectrum confirmed the presence of Lewis acid sites. The catalytic activity of PrAlPO-5 was evaluated in the synthesis of campholenic aldehyde from α-pinene. The epoxidation of α-pinene through chemisorbed oxygen followed by isomerisation of α-pinene oxide over Lewis acid sites on PrAlPO-5 yielded campholenic aldehyde selectively. PrAlPO-5 was proved to be an active, selective and reusable catalyst.