The critical micelle concentration (CMC) of the selected surfactant belonging to quaternary ammonium salts with chemical designation N,N-dimethyl-N-(3-((1R,5S)-1,8,8-trimethyl-2,4-dioxo-3-azabicyclo[3.2.1]octane-3yl)propyl)hexadecane-1-amine bromide was determined. Simultaneously, the effect of the addition of various concentrations of NaCl, KCl, NaBr, and KBr salts on the CMC value of the substance was observed and compared with those obtained in an aqueous solution at T = 296,15 K. Based on the results obtained, it was concluded that NaCl and KCl salts decreased the critical micelle concentration, while NaBr and KBr salts did not support micellization and CMC values therefore increased. In the case of solutions of a substance in the salt environment, when compared to the substance's solution in distilled water, a decrease in partial molar volume was observed. From the concentration density dependencies of the substance, an ionization degree of α was determined. Finally, the molar Gibbs energy ∆G° was also calculated and found negative for all salt solutions, while increase with their increasing concentration.
Použitím absorpčnej spektroskopie UV/VIS s pyrénom bola preskúmaná micelizácia vybraných kvartérnych amóniových solí odvodených od heptakaínu (látky s pracovným označením H22, H26, H27, H29, H34, H37, H + Al a H + B) vo vodných prostrediach a derivát H34 v 3 mol/l etanolovom roztoku pri teplote 25 °C. V homologickom rade študovaných bromidov H22, H26, H27 a H29 hodnoty cmc exponenciálne závisia od počtu atómov uhlíka nC v hydrofóbnom reťazci: ln (cmc) = –3,131–0,421nC. Voľná Gibbsova energia prenosu jednej metylénovej skupiny alkylového reťazca z vodnej fázy do vnútra micely pri teplote 25 °C má hodnotu (–0,421 ? 0,034)RT.
Micellization of selected quaternary ammonium compounds derived from heptacaine have been studied by absorption spectroscopy in the UV/VIS spectral region with the use of a pyrene probe. The compounds studied in the aqueous solution have been marked as H22, H26, H27, H29, H34, H + Al and H + B and the derivative marked as H34 was studied in a 3 mol/l ethanol solution at the temperature of 25 °C. In the homologous series of the studied bromides H22, H26, H27 and H29, cmc was observed to be dependent on the number of carbon atoms nc in the hydrophobic chain: ln (cmc) = –3.131–0.421nC. The Free Gibbs energy necessary for the transfer of a methyl group of the alkyl chain from the water phase to the inner part of the micelle at the temperature of 25 °C is (–0.421 ? 0.034)RT.
