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A Comparative Study of Structurally Related Homogeneous Ruthenium and Iron Catalysts for the Hydrogenation of Levulinic Acid to γ‐Valerolactone
Author(s) -
van Slagmaat Christian A. M. R.,
De Wildeman Stefaan M. A.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700938
Subject(s) - levulinic acid , chemistry , ruthenium , catalysis , acetonitrile , homogeneous , homogeneous catalysis , isopropyl alcohol , organic chemistry , inorganic chemistry , physics , thermodynamics
The conversion of levulinic acid (LA) to γ‐valerolactone (GVL) was investigated by employing the homogeneous Shvo catalyst ( Ru‐1 ) and iron Knölker‐type catalysts, in order to evaluate the possibility to replace ruthenium with cheap, earth‐abundant iron for this catalytic reaction. While the ruthenium‐catalyzed reactions readily proceed, the activating agent required for the iron complex was found to interfere with the LA. This problem could be circumvented by pre‐activating the original Knölker complex ( Fe‐1 ) into the corresponding dicarbonyl mono‐acetonitrile iron species ( Fe‐3 ). The pre‐activated iron catalyst deactivated after a few turn‐overs in transfer hydrogenation reactions with isopropyl alcohol; however, highly improved GVL yields were achieved under H 2 pressure to a notable maximum of 570 turn‐overs for Fe‐3 . Nevertheless, comparative screening experiments with various solvents and kinetic studies showed that Ru‐1 is still superior over Fe‐3 in terms of catalytic activity.