Figure 10.

The effect of in situ solvent and reagent recycling on the E‐factor (A) and the carbon footprint (B, C) of the continuous‐flow synthesis. The main contributors of the environmental burden are the solvent waste and the energy to operate the thermostat for the jacket of the flow reactor. The rest of the contributors have cumulative contributions lower than 0.5 %. Refer to the Supporting Information for the actual values for all contributors. Based on the acetone solvent recovery flowrate and the density of the different solvents, the potential of nanofiltration for the carbon footprint reduction can be estimated25 for the most common solvent wastes5 generated in the pharmaceutical sector (D).