Which DES or IL do you want to prepare?

I need to create de Novo one not a previous one for research project

Designing new ionic liquids is not an easy task, you have to consider if what comes out will be liquid, if it will be stable enough, and so on. If you want to dissolve cellulose, you need an ionic liquid, that has good hydrogen acceptor properties ( i.e. the so called β Kamlet-Taft parameter), so that it can disrupt the hydrogen bonds in cellulose and thus dissolve it. The higher this parameter is, the better the solubility. Usually some phosphoric acids and esters or carboxylic acids have such.

The synthesis of ionic liquids (ILs) for lignocellulosic biomass hydrolysis typically involves creating imidazolium-based or choline-based compounds. For imidazolium ILs like 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), the process begins with alkylation where 1-methylimidazole reacts with ethyl bromide in a 1:1 molar ratio at 70°C for 24 hours to form [EMIM][Br]. This is followed by anion exchange where the bromide ion is replaced with acetate using either silver acetate or an ion-exchange resin, with subsequent purification through filtration and solvent removal under vacuum. Choline-based ILs such as choline lysinate ([Ch][Lys]) are synthesized more simply by neutralizing choline hydroxide with lysine in a 1:1 molar ratio in aqueous solution, followed by water removal through rotary evaporation. While imidazolium ILs show excellent biomass dissolution capabilities, their high cost and toxicity make choline-based alternatives more attractive for sustainable applications, despite potentially requiring higher operating temperatures.

Deep eutectic solvents (DES) offer a more environmentally friendly alternative and are simpler to prepare. Common DES formulations combine choline chloride with hydrogen bond donors like urea or lactic acid in specific molar ratios (typically 1:2). The synthesis involves mixing the components and heating at 80-100°C with continuous stirring until a homogeneous liquid forms, usually within 1-2 hours. The resulting solvent can be used directly or dried under vacuum to remove residual moisture. DES systems are particularly advantageous due to their low toxicity, biodegradability, and ability to operate under milder conditions compared to conventional ILs, though they may require longer processing times for effective biomass breakdown.

For biomass pretreatment applications, both ILs and DES follow a similar operational sequence. The biomass (typically 5-10% by weight) is dissolved in the solvent at elevated temperatures ranging from 80-150°C for periods between 30 minutes to 12 hours, depending on the specific solvent and biomass type. Following dissolution, an antisolvent such as water or ethanol is added to precipitate the cellulose and lignin fractions. The solvents can then be recovered through antisolvent evaporation and reused, with DES generally offering easier recovery and lower environmental impact compared to many ILs. The choice between ILs and DES ultimately depends on balancing processing efficiency against economic and environmental considerations, with DES systems like choline chloride-lactic acid mixtures being particularly promising for large-scale applications due to their favorable sustainability profile and competitive performance.