Test lab sheet


WP2 – LA2.04

Main tool(s) used for IEMAP

Ionic liquid synthesis laboratory, chemical fume hood, magnetic mixer, wash water aspirator, glass vacuum stove, glove-box

Type of measurements that are possible to be made in this laboratory, with this instrument(s)

Ionic liquid synthesis/purification and electrolyte components

ApplicationIonic liquids

List of deliverables delivered to SAL2DeliverableD2.5 (Final Report)


Giovanni Battista Appetecchi -ENEA-Casaccia – SSPT Department.

S. Maria di Galeria (Rome)


Figure 1


Schematic diagram of the overall one-pot process, performed in aqueous solvent, for the synthesis of hydrophobic ionic liquids. Red dashed area (1): one-pot synthesis of ionic liquid. Green dashed area (2): ionic liquid purification. Blue dashed area: ionic liquid anhydrification.  = liquid components. = solid components.

Figure 2


Evolution of process temperature (panel A) and overall yield (panel B) as a function of process time for different batches of PYR14TFSIionic liquid obtained by one-pot reaction starting from similar initial temperature (Tin = 47 °C) of the reactants.

Level of innovation

In LA2.4, an innovative, potentially automatable process for the environmentally sustainable synthesis of ionic liquids was designed and developed. This process, referred to as one-pot, employs deionized water as the only process solvent, can be carried out by a single reaction stage in a much faster time than that required by standard synthesis procedures, and is self-sustaining, i.e., requires no energy for the synthesis to proceed. Such a process results in lower energy consumption, which, together with the low cost of the solvent (water), produces a marked reduction in production costs. The one-pot process can be amenable to automation given the relative simplicity of execution and has considerable flexibility, i.e., it can be used for the preparation of a wide variety of families of ionic liquids (mainly hydrophobic but also hydrophilic) that can be made up of a variety of cations and anions and, at the same time, allows for wide variation in the nature/type of functional groups bound to the ions. The one-potprocess can be easily performed continuously and is, potentially amenable to automation (both the synthesis and purification stages are not particularly problematic and can be performed distinctly in succession).


Conference:7th ICNaB 2022 (International Conference on Sodium Batteries), Ulm (Germany), December 5-8, 2022.

Authors: G. Maresca, S. Brutti, G.B. Appetecchi

Title: Ionic liquid electrolytes for sodium battery systems

Description of results achieved in this SAL2

During the 2nd year (ended at SAL2) under LA2.4. line, the feasibility of an innovative process (called one-pot) for the synthesis of ionic liquids by means of tests/investigations performed in the laboratory was verified, also in order to assess the possibility of its execution performed continuously and, therefore, automation. (Ionic liquids are molten salts at room temperature proposed as innovative, nonvolatile and nonflammable solvents in order to increase the safety and reliability of lithium batteries.) Different operational parameters were investigated, and special attention was paid to the reproducibility of the results obtained. Ionic liquid PYR14TFSI, widely investigated and proposed for lithium batteries, was selected as a reference material.

The one-pot reaction can be carried out in a single stage, uses water as the only process solvent, and is self-sustaining, that is, it does not require any external heating (exploiting the heat from the exothermic dissolution of the reactants in the aqueous solvent). The results obtained showed that the one-pot process exhibits excellent reproducibility and can be easily brought to completion in aqueous medium simply by adjusting the initial temperature of the process, that is, by varying the amount of aqueous solvent. At an initial temperature (Tin) of 47 °C (measured at the beginning of the reaction), a maximum value, reached by the temperature during the reaction, of 80 °C was recorded. Under these operating conditions, the process yield reaches the maximum possible value (95 percent) after a reaction time of 30 minutes. More prolonged reaction times do not result in any increase in process yield. However, the fraction of ionic liquid dissolved in the aqueous phase can be completely recovered from the aqueous phase. Purification of the ionic liquid (crucial for application in electrochemical devices) was conducted by simple washes in water and vacuum drying (moisture removal). These characteristics, in combination with high sustainability, lower cost, reduced process time, ease of execution, and flexibility (possibility of synthesizing various types of ionic liquid following the same procedure), are also of particular relevance in view of possible industrial applications.

Therefore, the one-pot process, given its overall execution characteristics, can be conducted continuously (without interruption) and is amenable to automation.