Methyl levulinate (ML) is a biobased platform molecule, which has versatile applications in fine chemical synthesis and food additives. However, during the ML production, one of the main barriers is that humins are usually cogenerated, which leads to poor reaction efficiency and catalyst deactivation. The following findings are herein reported for the first time: in a catalytic system with H-beta25, molecular oxygen could act as both a humins cleaner and a reaction accelerator for the synthesis of value-added ML from 5-hydroxymethylfurfural (HMF) or furfuryl alcohol (FA). The reaction efficiency and the catalyst reusability were significantly improved in the presence of oxygen. Besides, the effects of different reaction parameters as well as catalysts have been investigated. The mechanism of ML formation from HMF in the presence of O 2 and the role of O 2 in humins removal were also proposed.

Direct valorization of furfural into alkyl levulinates and γ‐valerolactone in primary alcohols with rare‐earth metal catalysts via transfer hydrogenation was firstly reported. The effects of different rare‐earth metal salts and hydrogen donors, as well as reaction parameters on the conversion of furfural were evaluated. Under optimal conditions, ca. 74 % yield of ethyl levulinate was directly produced from furfural in ethanol with YI3 as the catalyst, and more than 60 % of γ‐valerolactone was yielded using YBr3. And intriguingly, it has been demonstrated that primary alcohols, such as ethanol, n‐propanol etc., have superior catalytic activity than secondary alcohol due to their multiple roles in the reaction. The present study provides a green, simple and efficient way for the valorization of biomass derived furfural.

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