To perform quaternization, quinine free base of high purity was obtained from quinine monohydrochloride dihydrate of technical grade using the previously developed precipitation method . First, quinine monohydrochloride dihydrate was dissolved in anhydrous acetonitrile (0.9 dm 3 per 100 g of hydrochloride) at 25 °C, and then, an equimolar amount of potassium hydroxide was added. The precipitate was filtered off and thoroughly washed with warm (40-50 °C) water. In the next stage, the obtained quinine free base was subjected to quaternization with 1-bromoalkanes comprising 4, 8, or 12 carbon atoms in the alkyl chain according to the methodology described previously . 1-(2-Hydroxyethyl)quininium bromide was obtained according to a similar methodology. First, quinine free base (0.03 mol) was alkylated using 2-bromoethanol (0.0315 mol). The reaction was conducted for 48 hours at 35 °C, and DMF (30 cm 3 ) was used as a preferred solvent. The post-reaction mixture was transferred to a dropping funnel and added dropwise to vigorously stirred ethyl acetate, and the resulting precipitate was filtered off, dried, and recrystallized twice from methanol-acetone (1:3 volumetric ratio). The resulting quaternary ammonium bromides were pulverized, dried and stored over P4O10. A semi-automatic EasyMax reactor with a vessel of 100 cm 3 equipped with a reflux condenser, a stir bar and a temperature sensor (Mettler Toledo, USA) was used to perform all quaternization reactions.