The effect of substrate size in the Beckmann rearrangement: MOFs vs. zeolites

Catalytic activity of CuBTC and FeBTC was investigated in Beckmann rearrangement of a series of aromatic and non-aromatic oximes and compared with that of zeolites Beta and USY. The reactivity of substrates in Beckmann rearrangement increases in the order camphor oxime < cyclohexanone oxime < indanone oxime < acetophenone oxime. While zeolites show higher activity in the transformation of relatively small aromatic (acetophenone oxime, indanone oxime) and non-aromatic oximes (cyclohexanone oxime) providing 100% selectivity to the target lactams in all reactions, CuBTC was the most active in transformation of bulky oximes. It was deduced, that textural preferences of CuBTC may be the reason of its capability to facilitate the transformation of bulky camphor oxime in comparison with zeolites Beta and USY.