Transfer Hydrogenation of Levulinic Acid to γ‐Valerolactone and Pyrrolidones Using a Homogeneous Nickel Catalyst

• Published in: European journal of inorganic chemistry 2021-02, Vol.2021 (5), p.445-450
• Main Authors: Jurado‐Vázquez, Tamara, Arévalo, Alma, García, Juventino J.
• Format: Article
• Language: English
• Subjects: Amines; Catalysts; Dehydrogenation; Ethane; Formic acid; Homogeneous catalysis; Hydrogenation; Inorganic chemistry; Levulinic acid; Nickel; Selectivity; Transfer hydrogenation
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202001063

We report a well‐defined homogeneous nickel‐based catalyst using the complex [dippeNi(COD)] (dippe=1,2‐bis(diisopropyl phosphino)ethane) as a catalytic precursor with high activity in the hydrogenation of levulinic acid (LVA) to yield γ‐valerolactone (GVL) under relatively mild conditions (4 h, 120 °C); formic acid (FA) is the transfer hydrogenation agent in a dehydrogenation‐hydrogenation process. Under optimized conditions, GVL was obtained with excellent yield (>99 %) and selectivity (>99 %). The Ni‐catalyst was assessed in the LVA hydrogenation with a variety of primary amines using an excess of FA (4 eq) as hydrogen donor at 15 h and 170 °C to produce 2‐pyrrolydones with excellent yield (>99 %) and fair to good selectivity (from 68 to 92 %). The first well‐defined homogeneous nickel‐based catalytic system for the transfer hydrogenation of levulinic acid to γ‐valerolactone and pyrrolidones is reported; key mechanistic insights are also documented, paving the way to sustainable processes.