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Keywords:

  • biomass;
  • carbon dioxide;
  • diketones;
  • heterogeneous catalysis;
  • furanes

Abstract

The one-pot production of industrially valuable diketone derivatives from carbohydrates is achieved through a bifunctional catalytic process. In particular, Pd/C-catalyzed hydrogenation of HMF in water and under CO2 affords 1-hydroxypentane-2,5-dione with up to 77 % yield. The process is also eligible starting from fructose and inulin, affording 1-hydroxyhexane-2,5-dione with 36 % and 15 % yield, respectively. The key of the process is reversible in situ formation of carbonic acid, which is capable of assisting Pd/C during the hydrogenation reaction by promoting the dehydration of carbohydrates and the ring-opening of furanic intermediates. Interestingly, by changing the reaction medium from H2O to a H2O/THF mixture (1:9), it is possible to switch the selectivity of the reaction and to produce 2,5-hexanadione with 83 % yield. Within the framework of sustainable chemistry, reactions presented in this report show 100 % carbon economy, involve CO2 to generate acidity, require water as a solvent, and are conducted under rather low hydrogen pressures (10 bar).