Vapor-Phase Conversion of Aqueous 3-Hydroxybutyric Acid and Crotonic Acid to Propylene over Solid Acid Catalysts

Shijie Leow, Andrew Koehler, Lauren Cronmiller, Xiangchen Huo, Gabriella Lahti, Yalin Li, Glenn Hafenstine, Derek Vardon, Timothy Strathmann

Research output: Contribution to journalArticlepeer-review

3 Scopus Citations


Diverse sources of wastewater organic carbon can be microbially funneled into biopolymers like polyhydroxybutyrate (PHB) that can be further valorized by conversion to hydrocarbon fuels and industrial chemicals. We report the vapor-phase dehydration and decarboxylation of PHB-derived monomer acids, 3-hydroxybutyric acid (3HB) and crotonic acid (CA), in water to propylene over solid acid catalysts using a packed-bed continuous-flow reactor. Propylene yields increase with increased Bronsted acidity of catalysts, with amorphous silica-alumina and niobium phosphate yielding 52 and 60 %C (percent feedstock carbon, max 75 %C) of feedstock 3HB and CA, respectively; additional products include CO2 and retro-aldol products (acetaldehyde and acetic acid). Deactivation studies indicate progressive and permanent steam deactivation of amorphous silica-alumina, while re-calcination partially recovers niobium phosphate activity. Experiments demonstrating sustained reactor operation over niobium phosphate provide a promising technology pathway for increasing valorization of organic-rich wastewater.
Original languageAmerican English
Pages (from-to)6866-6876
Number of pages11
JournalCatalysis Science and Technology
Issue number20
StatePublished - 2021

NREL Publication Number

  • NREL/JA-5100-81229


  • biopolymers
  • decarboxylation
  • hydrocarbon fuels
  • vapor-phase dehydration
  • watewater


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