Synthesis and application of geminal dicationic ionic liquids and poly (ionic liquids) combined imidazolium and pyridinium cations as demulsifiers for petroleum crude oil saline water emulsions

Abstract

New geminal dicationic ionic liquids, ILs, containing both imidazolium and pyridinium cations were synthesized to apply as effective demulsifiers for stable sea water-in-heavy petroleum crude oil emulsions. In this respect, vinyl imidazolium and 4- amino-4-pyridyl diethoxylate (APE) or 4-pyridyl tetradecanamide were quaternized either with 1,4-dibromobutane or 1,12-dibromododecane to produce ILs monomers. Their vinyl group was polymerized via solution radical polymerization to produce geminal poly (ionic liquids), PILs, and their chemical structures were identified by nuclear magnetic resonance. The thermal stability and thermal characteristics of the prepared geminal dicationic imidazolium and pyridinium cations indicate that all prepared compounds behave as ILs and PILs having lower melting temperature below 100 °C and lower glass transition temperatures below 0 °C. The surface activity, micellization or aggregation, and adsorption at air/seawater or seawater/petroleum crude oil interfaces were investigated from surface and interfacial tension measurements. The interactions of the prepared ILs and PILs with asphaltenes were evaluated from particle sizes and zeta potentials. The demulsification of stable W/O emulsions at temperature of 60 °C using different concentrations of the prepared ILs and PILs confirm that the demulsification was carried out at lower injection dose (from 100 to 250 ppm) and shorter demulsification time (from 40 to 240 min).