Micellization and thermodynamics study of n-alkyl-4-methylpyridinium bromides in water and mixed water–ethanol media
Journal of Molecular Liquids, cilt.352, 2022 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 352
- Basım Tarihi: 2022
- Doi Numarası: 10.1016/j.molliq.2022.118765
- Dergi Adı: Journal of Molecular Liquids
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, INSPEC
- Anahtar Kelimeler: Surfactants, n-Alkyl-4-methyl pyridinium bromide, Micellization, Thermodynamics of micellization, Conductivity measurements
- Kırklareli Üniversitesi Adresli: Evet
Özet
The micellization behaviors of n-decyl-4-methylpyridinium bromide, n-dodecyl-4-methylpyridinium bromide, and n-tetradecyl-4-methylpyridinium bromide were studied in water and mixed water–ethanol media by using conductivity measurements over the temperature range of 293.15–318.15 K. The critical micelle concentrations (CMC) of all n-alkyl-4-methyl pyridinium bromides studied increased with increasing temperature, but they decreased with increasing hydrocarbon chain length. Their CMC values of n-decyl-4-methylpyridinium bromide, n-dodecyl-4-methylpyridinium bromide, and n-tetradecyl-4-methylpyridinium bromide in water at the temperature range of 293.15–318.15 K were determined as in the range of 43.62–46.42, 10.45–11.57, and 2.78–3.20 mM, respectively. Moreover, the lowest CMC values of n-decyl-4-methylpyridinium bromide, n-dodecyl-4-methylpyridinium bromide, and n-tetradecyl-4-methylpyridinium bromide were found with 15, 5, and 5 vol% ethanol additions, respectively. The calculated negative ΔGm0 and ΔHm0 values proved that their micellizations in water and mixed water–ethanol media were spontaneous and exothermic. Also, ΔGm0 values became the more negative with the longer the hydrocarbon chain length. Furthermore, their micellization processes in water were determined to be entropy controlled, however enthalpic contributions in the mixed water–ethanol systems started to predominate with increasing ethanol concentrations and/or temperature.