Abstract:
The reduction of functional platform chemicals,
such as furfural, to industrially important chemicals and fuel
requires precise modulation of surface reactivity of the catalyst to
obtain the desired reactivity and selectivity. In this study, the
selective reduction of furfural (FAL) to furfuryl alcohol (FOL) and
tetrahydrofufuryl alcohol (THFA) is achieved by the transition
metal interplay in the framework structure of magnetic spinels
Fe3O4 and by modulating the reaction medium. Herein, FAL is
selectively and quantitatively reduced to FOL in water at very mild
reaction conditions over Pd-decorated CuFe2O4, whereas FAL is
selectively converted to THFA in hexane at mild reaction
conditions over Pd-decorated NiFe2O4, using H2 as an economical
reducing agent. The Pd loading, reaction temperature, H2 pressure,
and reaction time are minimized to obtain the best selectivity toward THFA. Different modes of FAL adsorption occur on CuFe2O4
and NiFe2O4 surfaces. Dissociative adsorption of H2 occurs on Pd sites to form Pd-H species, followed by transfer hydrogenation
from Pd-H to FAL adsorbed on spinels, leading to the formation of FOL or THFA. Efficient magnetic recyclability and the hot
filtration test show that the catalyst exhibits no significant loss in the activity even after five recycles. Catalysts exhibit very high
activity, selectivity, and low activation energy, which are very attractive for academic and industrial points of view.
