Synthesis of an ionic liquid demulsifier with double hydrophilic and hydrophobic chains

A new type of ionic liquid demulsifier with double hydrophilic and hydrophobic chains (HDEA-TFA) was synthesized through the quaternization and replacement reaction. The chemical structure of HDEA-TFA was identified by 1 H NMR and FT-IR. It could be applied as an excellent demulsifier for two water-in-crude oil (W/O) emulsions (m water :m oil  = 70:30 and m water :m oil  = 30:70). The effect of demulsification conditions such as concentration of HDEA-TFA, settling time, demulsification temperature, pH value and salinity on the demulsifying efficiency (DE) of the W/O emulsions were discussed in detail. The results showed that the demulsifying efficiency (DE) of HDEA-TFA in the two W/O emulsions could reach 100 % with the concentration of 500 mg/L at 60 °C within 120 min. Also, HDEA-TFA had excellent acidic, alkaline and salt resistance. Moreover, several commercial demulsifiers were compared to evaluate the demulsifying performance of HDEA-TFA. The dynamic interfacial tension (IFT), surface tension (ST), three-phase contact angle (CA), elasticity modulus (EM) and zeta potential were used to investigate the demulsifying mechanism. The current study developed a new type of ionic liquid demulsifier with excellent performance and provided a reference for the research of demulsification mechanism.