Nano silica and molybdenum supported Re, Rh, Ru or Ir nanoparticles for selective solvent-free glycerol conversion to cyclic acetals with propanone and butanone under mild conditions

- Nano-Re/SiO2 appeared highly efficient and selective catalyst in glycerol acetalization.
- TON for glycerol to solketal (Re/SiO2) significantly outperforms literature values.
- Mo supported Re, Ir, Rh, Ru were tested as catalysts in glycerol acetalization.
- Re, Ir, Rh and Ru/SiO2 catalytic activity was correlated with electronic properties.

We described the preparation of a series of new catalysts, i.e., nano-silica supported Re, Ru, Ir, Rh NPs as well as various combinations of the above-mentioned metals as potential catalysts of glycerol acetalization with acetone or butanone for the first time. In fact, it was discovered that nano-SiO2 supported Re in particular is a highly efficient selective catalyst of glycerol acetalization for five-membered cyclic acetals. While Re supported on nano-SiO2 prefers five-membered cycles its replacement to Mo destroys this selectivity and both five- and six-membered products can be observed. Under optimal conditions, the TON that was observed significantly outperforms those that have been reported in the literature for other catalytic systems.

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