Catalytic hydrogenation of levulinic acid to ɣ-valerolactone: Insights into the influence of feed impurities on catalyst performance in batch and flow

H.C. Genuino, H.H. van de Bovenkamp, E. Wilbers, J.G.M. Winkelman, Andrey Goryachev, J.P. (Jan Philipp) Hofmann, Emiel J.M. Hensen, B.M. Weckhuysen (Corresponding author), P.C.A. Bruinincx (Corresponding author), Hero J. Heeres (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

7 Downloads (Pure)

Abstract

γ-Valerolactone (GVL) is readily obtained by the hydrogenation of levulinic acid (LA) and is considered a sustainable platform chemical for the production of biobased chemicals. Herein, the performance and stability of Ru-based catalysts (1 wt % Ru) supported on TiO 2 (P25) and ZrO 2 (monoclinic) for LA hydrogenation to GVL is investigated in the liquid phase in batch and continuous-flow reactors using water and dioxane as solvents. Particular attention is paid to the influence of possible impurities in the LA feed on catalyst performance for LA hydrogenation. Benchmark continuous-flow experiments at extended times on-stream showed that the deactivation profiles are distinctly different for both solvents. In dioxane, the Ru/ZrO 2 catalyst is clearly more stable than Ru/TiO 2, whereas the latter is slightly more stable in water. Detailed characterization studies on spent catalysts after long run times showed that the deactivation of Ru/TiO 2 is strongly linked to the reduction of a significant amount of Ti 4+ species of the support to Ti 3+ and a decrease in the specific surface area of the support in comparison to the fresh catalyst. Ru/ZrO 2 showed no signs of support reduction and displayed morphological and structural stability; however, some deposition of carbonaceous material is observed. Impurities in the LA feed such as HCOOH, H 2SO 4, furfural (FFR), 5-hydroxymethylfurfural (HMF), humins, and sulfur-containing amino acids impacted the catalyst performance differently. The results reveal a rapid yet reversible loss of activity for both catalysts upon HCOOH addition to LA, attributed to its preferential adsorption on Ru sites and possible CO poisoning. A more gradual drop in activity is found when cofeeding HMF, FFR, and humins for both solvents. The presence of H 2SO 4, cysteine, and methionine all resulted in the irreversible deactivation of the Ru catalysts. The results obtained provide new insights into the (ir)reversible (in)sensitivity of Ru-based hydrogenation catalysts to potential impurities in LA feeds, which is essential knowledge for next-generation catalyst development.

Original languageEnglish
Pages (from-to)5903-5919
Number of pages17
JournalACS Sustainable Chemistry & Engineering
Volume8
Issue number15
DOIs
Publication statusPublished - 20 Apr 2020

    Fingerprint

Keywords

  • Biobased chemicals
  • Catalyst deactivation
  • Catalyst stability
  • Ruthenium catalysts
  • Zirconia and titania supports

Cite this