Green solvents

The omnipresence of solvents (organic and aqueous) in specialty chemistry generates a considerable amount of waste and requires the development of extraction processes that are often costly and time-consuming. In addition, the introduction of increasingly stringent regulations has led industry and academia to rethink the "solvent problem". This situation offers the skilled worker an opportunity to open up and evolve towards a more sustainable and environmentally-friendly chemistry, through the search for alternative processes or solvents.

Although solvent-free approaches are now being re-examined, in most cases solvent substitution is essential. To this end, decision-support tools (Hansen-HSP method, COSMO-RS-type in silico approaches) have been developed, but the experimenter's expertise is still essential.

Many alternatives are available on the market today, or are currently being developed. However, given the cost involved in changing a process, the choice of "THE" replacement solution is often crucial and difficult. Nevertheless, this notion of cost needs to be analyzed with discernment, and in particular compared with the real (and future) costs associated with the reprocessing and/or destruction of solvents in current processes.

To help users make the right choices, we present an overview of the main alternative solutions, and discuss the relevance of each in both environmental and economic terms. The advantages/disadvantages of each of these approaches will be discussed.