An efficient and scalable room temperature aerobic alcohol oxidation catalyzed by iron chloride hexahydrate/mesoporous silica supported TEMPO

An efficient room temperature catalytic system FeCl3 center dot 6H(2)O/SBA-15-TEMPO/NaNO2 for the oxidation of alcohols with dioxygen or air as terminal oxidant'has been developed. Various alcohols were oxidized at a low catalyst loading (0.1-1 mol %) to the corresponding carbonyl compounds in good to excellent yields. For the oxidation of benzyl alcohol, the excellent turn-over frequency (TOP) of 81.4 h(-1) was achieved (turn-over number (TON) up to 9770). The catalyst SBA-15-TEMPO can be reused for 10 reaction runs without significant loss of catalytic activity. In addition, the two components FeCl3 center dot 6H(2)O and SBA-15-TEMPO can also be reused for at least four reaction runs without appreciable loss of catalytic activity. In the case of large-scale experiment for the oxidation of benzyl alcohol, the desired product benzaldehyde was obtained in 94.5% yield. (C) 2013 Elsevier Ltd. All rights reserved.