TY - JOUR
T1 - Catalytic hydrogenation of levulinic acid to ɣ-valerolactone: Insights into the influence of feed impurities on catalyst performance in batch and flow
AU - Genuino, H.C.
AU - van de Bovenkamp, H.H.
AU - Wilbers, E.
AU - Winkelman, J.G.M.
AU - Goryachev, Andrey
AU - Hofmann, J.P. (Jan Philipp)
AU - Hensen, Emiel J.M.
AU - Weckhuysen, B.M.
AU - Bruinincx, P.C.A.
AU - Heeres, Hero J.
PY - 2020/4/20
Y1 - 2020/4/20
N2 - 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.
AB - 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.
KW - Biobased chemicals
KW - Catalyst deactivation
KW - Catalyst stability
KW - Ruthenium catalysts
KW - Zirconia and titania supports
UR - http://www.scopus.com/inward/record.url?scp=85084597064&partnerID=8YFLogxK
U2 - 10.1021/acssuschemeng.9b07678
DO - 10.1021/acssuschemeng.9b07678
M3 - Article
VL - 8
SP - 5903
EP - 5919
JO - ACS Sustainable Chemistry & Engineering
JF - ACS Sustainable Chemistry & Engineering
SN - 2168-0485
IS - 15
ER -
