The acidity values of ternary DES-like mixtures based on choline chloride, lactic acid, and dihydric alcohols

Among the unique and interesting types of solvents are DES-like mixtures, which with their significant physicochemical properties, which they meet the criteria of green solvents, such as sustainability, biodegradability and safety have attracted wide attention of the scientific community in many applications. Among the most important physical properties of DES-like mixtures, the acidity and alkalinity determine their applicability in various industries. In this work, the objective was to analyze the acidity of systems containing choline chloride (ChCl), lactic acid (LacA), and various dihydric alcohols in molar ratios of 1:1:1 to 1:5:1 and to express it using milliequivalents of acids per kilogram of solvent. DES-like mixtures based on ChCl/LacA/1,3-propanediol had an acidity of 1072 & PLUSMN; 82 meq/kg (1:1:1) to 4293 & PLUSMN; 257 meq/kg. For systems composed of ChCl/LacA/1,2butanediol; ChCl/LacA/1,3-butanediol; ChCl/LacA/1,4-butanediol; ChCl/LacA/1,5-pentanediol acidity values ranged from 1511 & PLUSMN; 117 meq/kg (1:1:1) to 5348 & PLUSMN; 96 meq/kg (1:5:1); 1128 & PLUSMN; 89 meq/kg (1:1:1) to 4489 & PLUSMN; 304 meq/kg (1:5:1), 914 & PLUSMN; 76 meq/kg (1:1:1) to 4314 & PLUSMN; 22 meq/kg (1:5:1), and 908 & PLUSMN; 65 meq/kg (1:1:1) to 4137 & PLUSMN; 23 meq/kg (1:5:1), respectively. As the ratio increased, the acidity of these systems also increased, while the pH values of all input systems were approximately the same and did not change significantly.