oxidized to the corresponding unsaturated lactones with very high chemoselectivity. The catalyst is also selective for the oxidation of aromatic aldehydes with H2O2, producing the formate ester or the corresponding hydrolyzed product, that is the alcohol. Shape-selective oxidations are observed for isomeric reactants with different molecular shapes. The catalytic Sn sites have been characterized by 119Sn
Sn-Beta用作Baeyer-Villiger与
过氧化氢反应的非均相催化剂。环状酮被转化成相应的内酯,而不饱和酮则以非常高的
化学选择性被氧化成相应的不饱和内酯。该催化剂对于用H 2 O 2氧化芳族醛也是选择性的,产生
甲酸酯或相应的
水解产物,即醇。对于具有不同分子形状的异构体反应物,观察到形状选择氧化。已经通过119Sn MAS-NMR光谱表征了催化的Sn位点,并且已经证明了四面体结合到
沸石骨架中。原位红外光谱和18 O标记实验表明,氧化机理涉及Criegee型中间体。