Specific conductivities of local anaesthetic 1-methoxy-3-(4-methylpiperazin-1-yl)propan-2-yl-4-propyl-oxyphenyl carbamate (LM9) in aqueous solution were measured as a function of the concentration and temperature. The critical micelle concentration, CMC, degree of ionization and the counterion binding of the micelle were estimated from the dependence of the specific conductivity measurements at various temperatures. The dependence of CMC on temperature was shown to be U-shaped with a minimum at the temperature T = 298.15 K. Thermodynamic parameters (Gibbs energy ΔG°, enthalpy ΔH°, entropy ΔS°) for the micelle system were estimated by applying the mass action model. Molecule LM9 exhibited the enthalpy-entropy compensation phenomenon. The compensation temperature Tc of the studied compound was 301.79 K.
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.
- MeSH
- kvartérní amoniové sloučeniny * analýza chemie klasifikace MeSH
- lidé MeSH
- piperidiny analýza chemie MeSH
- spektrofotometrie ultrafialová * metody využití MeSH
- statistika jako téma MeSH
- výzkum MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
