Mild electrocatalytic hydrogenation of lactic acid to lactaldehyde and propylene glycol

Tulika S. Dalavoy, James E. Jackson, Greg M. Swain, Dennis J. Miller, Jie Li, Jacek Lipkowski

    Research output: Research - peer-reviewArticle

    • 20 Citations

    Abstract

    Reduction of fermentation-derived lactic acid (LA) offers a renewables-based pathway to propylene glycol (PG), a large-scale commodity chemical, currently manufactured by the oxidation of petroleum-derived propene. Complementing our previously described catalytic hydrogenation of LA to PG, we now report electrocatalytic hydrogenation (ECH) of LA in an aqueous electrolyte using constant current electrolysis. A reticulated vitreous carbon (RVC) electrode serves to agglomerate, support, and supply current to a 5% Ru/C powder catalyst, the same catalyst used in the classical hydrogenations. The ECH conditions are mild (ambient pressure, 70 °C vs 1500 psi H2, 150 °C) relative to the chemical hydrogenation. More surprisingly, the major electrohydrogenation product is lactaldehyde (LAL), with small quantities of PG also formed. Variable current studies in the range of 10-100 mA show an increase in product yields and a shift in selectivity toward PG with increasing current. Experiments carried out with different acids as electrolytes reveal a distinct effect of the anion on the yields of the two products. In situ ATR-FTIR studies of the ECH of LA point to a chelating bidentate carboxylate adsorption mode for lactate on the Ru surface and offer insight into the effects of electrolyte anions on surface adsorption and reactivity.

    LanguageEnglish (US)
    Pages15-28
    Number of pages14
    JournalJournal of Catalysis
    Volume246
    Issue number1
    DOIs
    StatePublished - Feb 15 2007

    Profile

    lactic acid
    propylene
    hydrogenation
    glycols
    Propylene Glycol
    Hydrogenation
    Lactic Acid
    lactaldehyde
    Lactic acid
    Glycols
    Propylene
    electrolytes
    products
    Electrolytes
    anions
    catalysts
    adsorption
    Anions
    Adsorption
    Catalysts

    Keywords

    • ATR
    • Electrocatalytic hydrogenation
    • Electrosynthesis
    • FTIR
    • Green chemistry
    • Lactaldehyde
    • Lactic acid
    • Organic electrochemistry
    • Propylene glycol
    • Reticulated vitreous carbon
    • SEIRAS

    ASJC Scopus subject areas

    • Catalysis
    • Process Chemistry and Technology

    Cite this

    Mild electrocatalytic hydrogenation of lactic acid to lactaldehyde and propylene glycol. / Dalavoy, Tulika S.; Jackson, James E.; Swain, Greg M.; Miller, Dennis J.; Li, Jie; Lipkowski, Jacek.

    In: Journal of Catalysis, Vol. 246, No. 1, 15.02.2007, p. 15-28.

    Research output: Research - peer-reviewArticle

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