Molecular Ruthenium Cyclopentadienone Bifunctional Catalysts for the Conversion of Sugar Platforms to Hydrogen

Molecular ruthenium cyclopentadienone complexes were employed for the first time as pre-catalysts in the homogeneously catalysed Aqueous Phase Reforming (APR) of glucose. Shvo's complex resulted the best pre-catalyst (loading 2 mol%) with H-2 yields up to 28.9% at 150 degrees C. Studies of the final mixture allowed to identify the catalyst's resting state as a mononuclear dicarbonyl complex in the extracted organic fraction. In situ NMR experiments and HPLC analyses on the aqueous fraction gave awareness of the presence of sorbitol, fructose, 5hydroxymethylfurfural and furfural as final fate or intermediates in the transformations under APR conditions. These results were summarized in a proposed mechanism, with particular emphasis on the steps where hydrogen was obtained as the product. Benzoquinone positively affected the catalyst activation when employed as an equimolar additive.

Automated summary

Molecular ruthenium cyclopentadienone complexes were used as pre-catalysts in the homogeneously catalysed Aqueous Phase Reforming (APR) of glucose for the first time. Shvo's complex was identified as the best pre-catalyst (loading 2 mol%) with H-2 yields up to 28.9% at 150 degrees C. In situ NMR experiments and HPLC analyses revealed the presence of sorbitol, fructose, 5-hydroxymethylfurfural and furfural as final products or intermediates in the transformations under APR conditions. Benzoquinone was found to positively affect catalyst activation when used as an equimolar additive.