XNi–yCu–ZrO2 catalysts for the hydrogenation of levulinic acid to gamma valorlactone

Daniel R Jones,Jonathan K Bartley,Peter J Miedziak,Graham J Hutchings,Liam Thomas,Christian Reece,Satoshi Ishikawa,Sarwat Iqbal,David J Morgan,David J Willock,Wataru Ueda

doi:10.1080/2055074x.2018.1433598

Daniel R Jones, Jonathan K Bartley + Show 9 more

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https://doi.org/10.1080/2055074x.2018.1433598

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Abstract

We have investigated xNi–yCu–ZrO2 catalysts for the selective synthesis of γ-valerolactone from levulinic acid (LA). A series of xNi–yCu–ZrO2 catalysts with a consistent metal loading of 50% but varying Ni and Cu composition were prepared by an oxalate gel precipitation method and tested for LA hydrogenation. Ni-rich catalysts showed higher catalytic activity compared with Cu-rich formulations with a 45Ni–5Cu–ZrO2 composition yielding 76% γ-valerolactone after a reaction time of 30 min at 200 °C. Characterisation of the materials by XRD, surface area measurements and TPR allow us to attribute the differences in performance seen for different compositions to particle size and nanoparticle dispersion effects. DFT calculations also showed that a shift of d-band centre to higher energies with the mole fraction of Ni in Cu–Ni alloys would be expected to lead to improved hydrogen dissociation in Ni-rich catalysts and so aid hydrogenation activity.

Highlights

Utilisation of biomass for the production of fuel and chemicals has become an important research topic because of growing concerns about the finite nature of fossil carbon reserves and the environmental impact of our continued dependence on these resources
We have recently shown that the oxalate gel co-precipitation method coupled with a pre-reduction of the catalyst prior to use can significantly enhance the activity of Cu–ZrO2 catalysts compared to alternative preparation methods
Whilst we have shown how Cu–ZrO2 catalysts produced via the oxalate gel route can give high activity and selectivity for the hydrogenation of levulinic acid (LA) to GVL, the reaction conditions required are more forcing than used with supported Ru or Pd catalysts

Summary

Introduction

Utilisation of biomass for the production of fuel and chemicals has become an important research topic because of growing concerns about the finite nature of fossil carbon reserves and the environmental impact of our continued dependence on these resources. The hydrogenation of LA to GVL has been reported using both homogeneous and heterogeneous catalysts [4,5]. Ru, Pd, and Pt have been the generally explored precious metal heterogeneous catalysts for the synthesis of GVL from LA with a particular focus on Ru due to its excellent performance for the liquid phase hydrogenation of this substrate [6,7,8,9]. Ir on polymer supports [11], Sn/ SBA-15 [12] and Pt–Pd/SBA-15 [13] have been identified as active catalysts for this hydrogenation reaction

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