Copper phosphate nanostructures catalyze dehydration of fructose to 5-hydroxymethylfufural

The nanostructured catalysts of copper hydrogen phosphate monohydrate and copper pyrophosphate were developed for catalyzing dehydration of fructose to 5-hydroxymethylfurfural under hot compressed water at 200 °C. As evidenced by X-ray absorption fine structure, X-ray diffraction, SEM, and TEM analyses, the CuHPO4·H2O (as-synthesized) exhibits needle-like nanocrystals, while the samples calcined at 600 °C and 900 °C display α-Cu2P2O7 phases in rod-like nanostructure and irregularly shaped microcrystal, respectively. Each copper is distributed throughout the phosphate network. Among all samples, the Cu2P2O7 catalysts with weak acid strength (+3.3 ≤ H0 ≤ +4.8) was highly active and selective for 5-hydroxymethylfurfural production with a yield of 36% and maximum turnover number, while no metal leaching was observed after the reaction.

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► The copper phosphates catalyze dehydration of fructose to 5-hydroxymethylfurfural
► X-ray absorption fine structure, X-ray diffraction, acid–base titration, and TEM
► The CuHPO4.H2O exhibits needle-like nanocrystals.
► The α-Cu2P2O7 are in rod-like nanostructure and irregularly shaped microcrystal.
► No metal leaching was observed after the reaction.