Shaped inorganic–organic hybrid catalysts based on solid molecular catalysts for continuous formic acid dehydrogenation

Abstract

A synthetic methodology for the immobilization of solid molecular catalysts (SMCs) in cylindrically shaped porous glass substrates was developed to facilitate their use in a continuous plug-flow reactor. The glass supports were coated with tailor-made alkoxysilanes to enable covalent attachment of, ‘in pore’ polymerized SMCs. Inorganic–organic hybrid catalysts based on BINAP-, terpyridine- and triazine were successfully prepared and tested in formic acid dehydrogenation after impregnation with 0.1 wt% Ru or Ir. In a plug-flow reactor, TOFs of up to 11 500 h⁻¹ and selectivities of 75 ppm CO could be observed at 160 °C, while at 100 °C the activity remained at 6200 h⁻¹ with a CO concentration of 79 ppm.