Abstract
Ionic liquids (ILs) are environmentally friendly compounds and their gemini types exhibit high thermal stabilities and high surface and interfacial activity. The main objective of this work is to prepare, characterize and investigate the demulsification efficiency of two gemini pyridinium surfactant ILs. They were prepared by the introduction of long chain decanoyl chloride to aminopyridine followed by quaternization with two dichloro spacers containing different ethylene oxide units (DCDE and TEGDC) to form MEGPy and TEGPy ILs, respectively. The structure properties of the prepared demulsifiers were investigated using different spectral tools including (HNMR)-H-1 and (CNMR)-C-13 and DLS. Also, their solubility and surface activity were investigated to confirm their ability to reduce surface tension (ST) and interfacial tension (IFT). Gemini pyridinium IL with triethylene oxide spacer (TEGP) showed higher ability to reduce both ST and IFT than that with mono ethylene oxide spacer (MEGP). Thanks to the ability of both TEGPy and MEGPy surfactant IL to reduce ST and IFT, they were applied successfully as demulsifiers for W/O emulsions with different water percentages. Demulsification study indicated that both TEGPy and MEGPy were able to demusify W/O emulsions with high performance which reached to 100% at low concentrations (250 ppm) for some compositions with higher activity to TEGP IL than MEGPy surfactant.