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Chatel G.,University of Alabama | Chatel G.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Rogers R.D.,University of Alabama
ACS Sustainable Chemistry and Engineering | Year: 2014

Lignin, one of the three subcomponents of lignocellulosic biomass (along with cellulose and hemicellulose), represents more than 20% of the total mass of the Earth's biosphere. However, essentially due to its complex structure, this renewable polymer derived from biomass is mainly burned as a source of energy in the pulp and paper industry. Today, the valorization of lignin into the production of chemical feedstocks represents a real challenge in terms of both sustainability and environmental protection. This review first briefly outlines the main points of this challenge and compares the different methods investigated by chemists over the past several decades, pointing out the major difficulties met. Next, the review highlights the recent use of ionic liquids (ILs) as solvents that have provided some new opportunities to efficiently convert lignin and lignin model compounds into value-added aromatic chemicals. Particular focus is given to these new strategies in terms of selectivity, separation and the unique compounds obtained for the oxidation of lignin using ILs. Finally, an assessment of the challenges that must be resolved in order for ILs to become an eco-friendly way of producing chemicals from biomass, including lignin, is proposed. © 2013 American Chemical Society. Source


Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics | Jerome F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Chemical Society Reviews | Year: 2013

Biomass and waste exhibit great potential for replacing fossil resources in the production of chemicals. The search for alternative reaction media to replace petroleum-based solvents commonly used in chemical processes is an important objective of significant environmental consequence. Recently, bio-based derivatives have been either used entirely as green solvents or utilized as pivotal ingredients for the production of innovative solvents potentially less toxic and more bio-compatible. This review presents the background and classification of these new media and highlights recent advances in their use in various areas including organic synthesis, catalysis, biotransformation and separation. The greenness, advantages and limitations of these solvents are also discussed. © 2013 The Royal Society of Chemistry. Source


Zhang Q.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Jerome F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
ChemSusChem | Year: 2013

Deconstructing cellulose: This highlight presents an emerging concept dealing with the mechanocatalytic deconstruction of biopolymers including cellulose, lignin, and lignocellulosic biomass. This dry treatment of biomass is expected to open new horizons in the field of biomass processing. In particular, mechanocatalysis is now considered as a promising entry into biorefinery. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Luo Y.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Alonso-Vante N.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Electrochimica Acta | Year: 2015

This work summarizes the advanced materials developed by various research groups for improving the stability of platinum (Pt), and Pt-based catalysts center toward the oxygen reduction reaction (ORR) in acid medium. The ORR stability enhancement of Pt catalytic center can be classified according to the different nature of the supporting materials, namely, carbon-, oxide-based-, and oxide-carbon composites. The enhancement and stability of a catalytic center can be related to either its electronic modification induced by a strong interaction with the support, another metal (alloy), or to geometric effects. In addition, other parameters come into play, the size, the morphology of the catalytic center, the temperature, the dispersion, and mass loading, along with the measuring methods. This mini-review mainly focusses on the stability improvement, depending on the substrate nature. This latter can be further modified via functionalization or by the chemical interaction nature between the substrate and catalyst. © 2015 Elsevier Ltd. All rights reserved. Source


Chatel G.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Macfarlane D.R.,Monash University
Chemical Society Reviews | Year: 2014

Ionic liquids, as reaction media, and sonochemistry are two recently developing fields of chemistry that present some similarities. Firstly, they constitute separately unconventional approaches to reaction chemistry that, in many cases, generate improvements in yield, rate and selectivity compared to classical chemistry, or even change the mechanisms or products expected. In addition, both are often associated with green chemistry concepts as a result of their properties and their possible eco-friendly uses. A recent trend has been to combine these two technologies in a range of different applications and the results demonstrate very significant and occasionally surprising synergetic effects. Here we critically review the advantages and limitations of the ionic liquid/ultrasound combination in different applications in chemistry, to understand how, and in which respects, it could become an essential tool of sustainable chemistry in the future. Many practical and theoretical aspects associated with this combination of techniques are not understood or resolved and we discus where fundamental studies might further advance this field. This journal is © the Partner Organisations 2014. Source

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