An ionic liquid demulsifier with double cationic centers and multiple hydrophobic chains

In this paper, an ionic liquid demulsifier (MDBr-IL) with double cationic centers and multiple hydrophobic chains was synthesized with N,N,N,N,-tetraglycidyl- 4,4-diaminodiphenylmethane as starting materials. The structure of MDBr-IL was characterized by Fourier transform infrared spectrometer (FT-IR) and 1 H nuclear magnetic resonance spectrometer ( 1 H NMR). Effect of a few key factors such as concentration, demulsifying time, demulsifying temperature, salinity and pH value on the demulsifying efficiency (DE) was detailly researched in a water-in-crude oil emulsion. When the concentration of MDBr-IL was 500 mg/L, the DE reached 95.24% at 60 °C for 180 min. Also, the DE could increase to 98.64% when the demulsifying temperature was 70 °C. In addition, MDBr-IL had an eminent resistance to acid, alkali and salt. Also, the salinity could further improve the demulsification performance. Interfacial properties and wettability were employed to investigate the possible demulsification mechanism. It demonstrated that MDBr-IL is a viable demulsifier for the separation of oil-water emulsions.