Glycerol to lactic acid conversion by NHC-stabilized iridium nanoparticles
Journal article, 2018
Hydrogen reduction of an Ir(I) complex featured by a bulky N-heterocyclic carbene (NHC) ligand in dichloromethane gave small-sized (1.8 nm) Ir nanoparticles (NPs) decorated with NHC ligands (IrNHC). 1,4-Dioxane solutions of the latter particles were successfully applied to convert glycerol into lactic acid in the presence of NaOH (i.e. 1 mol equivalent with respect to glycerol). IrNHC showed an atom-related TOF value of almost 104 h−1, an almost exclusive formation of liquid reaction products, a high selectivity for lactic acid (93.0%) and a complete recyclability in air atmosphere. Attempts to synthesize analogous NHC-stabilized Ir NPs on a high surface area carbon support (CK) by reducing the same Ir(I) precursor, supported onto CK, prior to the hydrogen reduction in water, gave almost naked CK-supported Ir NPs (1.4 nm). Their catalytic activity tested for the same reaction in water as reaction medium, exhibited much lower catalytic activity (4 × 103 h−1), a lower percentage of liquid reaction products (i.e. 27.0% of the converted glycerol) and a lower selectivity for lactic acid compared to IrNHC.
Iridium nanoparticles
1,4-Dioxane
NHC-ligand
Glycerol
Lactic acid
Author
Werner Oberhauser
Institute of Chemistry of Organometallic Compounds (ICCOM)
National Research Council of Italy (CNR)
Claudio Evangelisti
Consiglo Nazionale Delle Richerche
Institute of Molecular Science and Technologies
A. Liscio
Consiglo Nazionale Delle Richerche
Institute for organic syntheses and photoreactivity (ISOF-CNR)
Alessandro Kovtun
Consiglo Nazionale Delle Richerche
Institute for organic syntheses and photoreactivity (ISOF-CNR)
Yu Cao
Chalmers, Industrial and Materials Science, Materials and manufacture
Francesco Vizza
Consiglo Nazionale Delle Richerche
Institute of Chemistry of Organometallic Compounds (ICCOM)
Journal of Catalysis
0021-9517 (ISSN) 1090-2694 (eISSN)
Vol. 368 298-305Subject Categories
Inorganic Chemistry
Other Chemical Engineering
Organic Chemistry
DOI
10.1016/j.jcat.2018.10.024