Communications
Nanocatalysis
Bimetallic Nanoparticles in Supported Ionic Liquid Phases as
Multifunctional Catalysts for the Selective Hydrodeoxygenation of
Aromatic Substrates
Lisa Offner-Marko, Alexis Bordet, Gilles Moos, Simon Tricard, Simon Rengshausen,
Abstract: Bimetallic iron–ruthenium nanoparticles embedded
in an acidic supported ionic liquid phase (FeRu@SILP + IL-
SO3H) act as multifunctional catalysts for the selective hydro-
deoxygenation of carbonyl groups in aromatic substrates. The
catalyst material is assembled systematically from molecular
components to combine the acid and metal sites that allow
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hydrogenolysis of the C O bonds without hydrogenation of
the aromatic ring. The resulting materials possess high activity
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Scheme 1. Selective catalytic hydrodeoxygenation of aromatic carbonyl
compounds as a possible route to alkyl-substituted aromatics, opening
new synthetic pathways, for example, from Friedel–Crafts acylation
products or lignin derivatives.
and stability for the catalytic hydrodeoxygenation of C O
groups to CH2 units in a variety of substituted aromatic ketones
and, hence, provide an effective and benign alternative to
traditional Clemmensen and Wolff–Kishner reductions, which
require stoichiometric reagents. The molecular design of the
FeRu@SILP + IL-SO3H materials opens a general approach
to multifunctional catalytic systems (MM’@SILP + IL-func).
moieties from aromatic substrates, despite the fact that they
rely on the use of toxic reagents and/or create large amounts
of undesired and problematic waste.[1] Current synthetic
pathways involving the hydrodeoxygenation of aromatic
substrates cannot fulfill the requirements of high yields,
selectivity, stability, productivity, safety, and environmental
compatibility.[6] Consequently, recent efforts have been
devoted to the development of selective hydrodeoxygenation
catalysts, typically based on conventional materials for
heterogeneous catalysis.[7a–j] While promising results have
been obtained in some cases for individual substrates, most of
the traditional solid catalysts show severe limitations such as
low hydrogenation selectivity,[8a–c] restriction to only benzylic
carbonyl groups,[7a–c] low stability,[7d–e] formation of side-
products,[7f] or high catalyst loadings approaching almost
stoichiometric amounts of the active metal component.[7g]
In the present paper, we describe the design, preparation,
and application of novel bifunctional catalysts for the
selective hydrodeoxygenation of aromatic substrates using
a molecular approach to assemble the key components of the
active materials.
T
he catalytic hydrodeoxygenation of carbonyl groups to
methylene units in the side chains of aromatic substrates has
attracted considerable attention for the production of alkyl-
substituted aromatic structures in commodity and fine
chemicals.[1] It is also considered an important enabler for
the deoxygenation of building blocks from lignocellulosic
biomass towards value-added chemicals and tailor-made
fuels.[2a–f] However, the large-scale synthetic application of
this transformation has been hindered by the lack of suitable
catalysts that allow for selective catalytic hydrodeoxygenation
of aromatic ketones without concomitant hydrogenation of
the aromatic ring (Scheme 1).[3] Stoichiometric methods such
as the Clemmensen[4] and Wolff–Kishner[5] reductions often
remain the methods of choice for the removal of carbonyl
[*] M. Sc. L. Offner-Marko, Dr. A. Bordet, M. Sc. G. Moos,
M. Sc. S. Rengshausen, Dr. K. L. Luska, Prof. Dr. W. Leitner
Institut fꢀr Technische und Makromolekulare Chemie
RWTH Aachen University
Worringerweg 2, 52074 Aachen (Germany)
E-mail: walter.leitner@cec.mpg.de
The design of the catalyst was based on the analysis of the
desired sequence of bond-breaking and bond-forming events
to achieve the overall transformation, exemplified for benzy-
lideneacetone (1) as a prototypical substrate in Scheme 2. The
M. Sc. L. Offner-Marko, Dr. A. Bordet, M. Sc. G. Moos,
M. Sc. S. Rengshausen, Prof. Dr. W. Leitner
Max-Planck-Institut fꢀr Chemische Energiekonversion
45470 Mꢀlheim an der Ruhr (Germany)
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metal-catalyzed hydrogenation of the C C and C O bond
À
leads to the corresponding alcohol 1b. Then, the C O bond is
Dr. A. Bordet, Dr. S. Tricard, Prof. Dr. B. Chaudret
Laboratoire de Physique et Chemie de Nano-Objets
Universitꢁ de Toulouse, INSA, UPS, LPCNO, CNRS-UMR5215
135 Avenue de Rangueil, 31077 Toulouse (France)
broken through an acid-catalyzed E1- or E2-type mechanism,
resulting in a carbocation or olefin intermediate (only the
latter is shown for clarity in Scheme 2). A second metal-
catalyzed hydrogenation leads to butylbenzene (1d) as the
desired product. The catalytic hydrogenation of the aromatic
ring must be strictly avoided at each stage. Thus, the challenge
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
Angew. Chem. Int. Ed. 2018, 57, 1 – 7
ꢀ 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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