Solvent-free Reactions and the Use of Sustainable Solvents

One of the main efforts towards the development of sustainable chemistiy is the reduction in the generation of waste. The largest amount of waste produced by a reaction is typically associated with the solvent employed as it is the component added in the largest quantity and, usually not incorporated into the final product but rather removed and disposed of at the end of the process. For these reasons, many efforts are being devoted to the development of catalytic systems that can operate under solvent-free conditions. When the use of a solvent is mandatory, the efforts are directed towards the use of sustainable solvents. In this context, water, which is the only natural solvent, is the preferred choice. Other green alternatives are ionic liquids or supercritical carbon dioxide. 

In this section, we will focus on gold-catalysed reactions in the absence of solvent, in water and in ionic liquids and will highlight the greenest examples in the literature. 

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