Efficient conversion of renewable levulinic acid to n-butyl levulinate catalyzed by ammonium and silver co-doped phosphotungstic acid

•(NH4)0.5Ag0.5H2PW is a highly efficient catalyst for n-butyl levulinate synthesis.•(NH4)0.5Ag0.5H2PW shows excellent catalytic activity and reusability.•(NH4)0.5Ag0.5H2PW shows higher surface acid density and activity than Ag1H2PW.

Ammonium and silver co-doped phosphotungstic acid was developed as novel efficient catalyst for the synthesis of n-butyl levulinate. The catalyst was characterized by element analysis, FT-IR, XRD and Hammett indicator method. Among them, (NH4)0.5Ag0.5H2PW12O40 exhibited the highest catalytic activity, and the yield of n-butyl levulinate could reach up to 99.0% within 2 h. The results showed that the activity of (NH4)0.5Ag0.5H2PW12O40 was higher than that of single Ag+ or NH4+ doped H3PW and other representative catalysts reported by literatures. In addition, (NH4)0.5Ag0.5H2PW12O40 performed good reusability for this reaction.

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