Integrated Catalytic Conversion of γ-Valerolactone to Liquid Alkenes for Transportation Fuels

TLDR

Renewable fuel synthesis is a challenging yet critical research area. The study presents a strategy to convert aqueous gamma‑valerolactone, derived from biomass carbohydrates, into liquid alkenes suitable for transportation fuels without requiring external hydrogen. The process decarboxylates GVL over a silica/alumina catalyst at high pressure to generate butene and CO₂, then oligomerizes the butene on an acid catalyst such as H‑ZSM‑5 or Amberlyst‑70 to produce condensable alkenes, while the CO₂ stream can be captured or sequestered.

Abstract

Efficient synthesis of renewable fuels remains a challenging and important line of research. We report a strategy by which aqueous solutions of gamma-valerolactone (GVL), produced from biomass-derived carbohydrates, can be converted to liquid alkenes in the molecular weight range appropriate for transportation fuels by an integrated catalytic system that does not require an external source of hydrogen. The GVL feed undergoes decarboxylation at elevated pressures (e.g., 36 bar) over a silica/alumina catalyst to produce a gas stream composed of equimolar amounts of butene and carbon dioxide. This stream is fed directly to an oligomerization reactor containing an acid catalyst (e.g., H ZSM-5, Amberlyst-70), which couples butene monomers to form condensable alkenes with molecular weights that can be targeted for gasoline and/or jet fuel applications. The effluent gaseous stream of CO2 at elevated pressure can potentially be captured and then treated or sequestered to mitigate greenhouse gas emissions from the process.