Abstract
BACKGROUND
γ-Valerolactone (GVL) is a high value chemical obtained from hydrogenation of bio-derived levulinic acid (LA). Work to date has focused on batch pressurised catalytic systems where high GVL yield is challenging. In this work, the role of support redox and acidity properties is examined in the continuous gas phase hydrogenation of aqueous LA at ambient pressure over gold on Al2O3, CeO2 and TiO2; Pd/Al2O3 served as a benchmark in catalyst tests.
RESULTS
100% GVL yield was achieved under stoichiometric conditions (inlet H2/LA = 1) over supported Au (mean size = 3.0–4.3 nm). Greater catalytic activity was recorded for Au on reducible TiO2 and CeO2. Under the same reaction conditions, Pd/Al2O3 delivered higher LA consumption rates but promoted formation of pentanoic acid.
CONCLUSIONS
GVL formation proceeds via 4-hydroxypentanoic as reactive intermediate. Surface oxygen vacancies (confirmed by O2 titration) formed during temperature programmed reduction of reducible oxides activate LA for reaction. Greater GVL productivity (with full hydrogen utilisation) is demonstrated in this work relative to state-of-the art supported Pd and Ru catalysts.
γ-Valerolactone (GVL) is a high value chemical obtained from hydrogenation of bio-derived levulinic acid (LA). Work to date has focused on batch pressurised catalytic systems where high GVL yield is challenging. In this work, the role of support redox and acidity properties is examined in the continuous gas phase hydrogenation of aqueous LA at ambient pressure over gold on Al2O3, CeO2 and TiO2; Pd/Al2O3 served as a benchmark in catalyst tests.
RESULTS
100% GVL yield was achieved under stoichiometric conditions (inlet H2/LA = 1) over supported Au (mean size = 3.0–4.3 nm). Greater catalytic activity was recorded for Au on reducible TiO2 and CeO2. Under the same reaction conditions, Pd/Al2O3 delivered higher LA consumption rates but promoted formation of pentanoic acid.
CONCLUSIONS
GVL formation proceeds via 4-hydroxypentanoic as reactive intermediate. Surface oxygen vacancies (confirmed by O2 titration) formed during temperature programmed reduction of reducible oxides activate LA for reaction. Greater GVL productivity (with full hydrogen utilisation) is demonstrated in this work relative to state-of-the art supported Pd and Ru catalysts.
| Original language | English |
|---|---|
| Pages (from-to) | 2221-2228 |
| Number of pages | 8 |
| Journal | Journal of Chemical Technology and Biotechnology |
| Volume | 92 |
| Issue number | 9 |
| Early online date | 30 Mar 2017 |
| DOIs | |
| Publication status | Published - Sept 2017 |
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Fernando Cardenas-Lizana
- School of Engineering & Physical Sciences - Assistant Professor
- School of Engineering & Physical Sciences, Institute of Mechanical, Process & Energy Engineering - Assistant Professor
Person: Academic (Research & Teaching)