**1. Introduction**

Hydrogenation reactions of unsaturated compounds have been among the most extensively studied processes in catalysis for many years [1, 2]. To process, generally metallic catalysts are required. Nevertheless, one of the principal challenges facing the field of transition metal catalysis is the efficient recycling and the possibility to reuse the catalytic species.

Ionic liquids (ILs) were rapidly considered as very promising solvents for this purpose, due to their tunable physicochemical properties and capacity to immobilise catalysts. As their name indicates, ILs are ionic species containing an organic cation and presenting usually low melting points below 100°C [3, 4]. ILs have a negligible vapour pressure, are not so viscous over a wide temperature range and many are non-flammable [5]. Chemical and physical properties of ILs can be also refined through proper choice of cation and anion. For these reasons, ILs have been

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

intensively investigated for the last three decades as green alternatives to conventional organic solvents [6–8]. Indeed, their numerous properties confer to these compounds the opportunity to replace classical organic solvents and their fields of applications are numerous: electrochemistry, organic synthesis, catalysis, complexation, extraction, etc. [4]. However, their low biodegradability or the toxicity of their degradation products and their high (eco)toxicity led the scientific community to reduce their use or to find other greener alternatives [9–13]. Considering this aspect, biobased ionic liquids could be a good alternative to classical ionic liquids but their preparation remains relative long and costly [14].

This chapter will be dedicated to the description of hydrogenation procedures of (poly) alkenes or unsaturated ketones in biobased ionic liquids (ILs). In order to present this specific topic, the first part of the chapter will present the preparation of various biobased ionic liquids. Next, general procedures of hydrogenation in "classical" ILs will be developed according to recently published reviews. Finally, we will show that hydrogenation processes could be performed in biobased ILs with few examples.
