Analysis of kinetics and reaction pathways in the aqueous-phase hydrogenation of levulinic acid to form γ-Valerolactone over Ru/C

Omar Ali Abdelrahman, Andreas Heyden, Jesse Q. Bond

Research output: Contribution to journalArticle

167 Scopus citations

Abstract

Reaction pathways and kinetics governing the Ru-catalyzed hydrogenation of levulinic acid (LA) in the aqueous phase to form γ-valerolactone (GVL) were considered in a packed bed reactor. GVL can be produced by two distinct hydrogenation pathways; however, over Ru/C at temperatures below 423 K, it forms exclusively via intramolecular esterification of 4-hydroxypentanoic acid (HPA). Over Ru/C, reasonable hydrogenation rates of LA to HPA were observed at near-ambient temperatures (e.g., 0.08 s-1 at 323 K), but GVL selectivities are poor (<5%) under these conditions. Apparent barriers for LA hydrogenation and HPA esterification are 48 and 70 kJ mol-1, respectively, and GVL selectivity improves at higher temperatures alongside increasing mass transfer limitations in 45-90 μm catalyst particles. Reactivity and selectivity trends in LA hydrogenation below 343 K are well-described by an empirical kinetic model capturing sequential hydrogenation and esterification. Coupling stacked beds of Ru/C and Amberlyst-15 delivers high GVL yields (∼80%) at near ambient temperatures (323 K) and practical residence times.

Original languageEnglish (US)
Pages (from-to)1171-1181
Number of pages11
JournalACS Catalysis
Volume4
Issue number4
DOIs
StatePublished - Apr 4 2014

Keywords

  • angelicalactone
  • aqueous phase kinetics
  • hydrogenation
  • hydroxypentanoic acid
  • levulinic acid
  • ruthenium
  • γ-valerolactone

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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