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Title: Direct synthesis of furfuryl alcohol from furfural: catalytic performance of monometallic and bimetallic Mo and Ru phosphides
The catalytic properties of monometallic and bimetallic Ru and Mo phosphides were evaluated for their ability to selectively hydrogenate furfural to furfuryl alcohol. Monometallic MoP showed high selectivity (98%) towards furfuryl alcohol, while RuP and Ru 2 P exhibited lower selectivity at comparable conversion. Bimetallic promotional effects were observed with Ru 1.0 Mo 1.0 P, as the pseudo-first order reaction rate constant for furfural hydrogenation to furfuryl alcohol, k 1 , was at least 5× higher than MoP, RuP, and Ru 2 P, while maintaining a 99% selectivity. Composition-directed catalytic studies of Ru x Mo 2−x P (0.8 < x < 1.2) provided evidence that Ru rich compositions positively influence k 1 , but not the selectivity. The rate constant ratio k 1 /( k 2 + k 3 ) for furfuryl alcohol production compared to methyl furan ( k 2 ) and tetrahyrofurfuryl alcohol ( k 3 ) followed the trend of Ru 1.0 Mo 1.0 P > Ru 1.2 Mo 0.8 P > MoP > Ru 0.8 Mo 1.2 P > RuP > Ru 2 P. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to examine the configuration of adsorbed furfural on the synthesized catalysts, but the more » results were inconclusive and no correlation could be found with the selectivity due to the possible IR inactive surface modes with furfural adsorption. However, gas phase density functional theory calculations suggested the x = 1.0 material in Ru x Mo 2−x P (0.8 < x < 1.2) had the most favorable furfural adsorption energy. Experimentally, we also observed that the solvent greatly influenced both the conversion and selectivity, where isopropanol provided the highest selectivity to furfuryl alcohol. Finally, recycling experiments showed a 12% decrease in k 1 after 3 cycles without any regeneration, but the activity could be fully recovered through a re-reduction step. « less
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Catalysis Science & Technology
Page Range or eLocation-ID:
3656 to 3668
Sponsoring Org:
National Science Foundation
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