A low temperature demulsifier with double hydrophobic chains was prepared by a one-step method

A demulsifier (PEDA) with double hydrophobic chain structure was synthesized using polyethylene glycol diglycidyl ether (PEDGE) and dodecyl amine (DA) as starting materials by a one-step method. The PEDA was characterized by FT-IR, 1H NMR and thermogravimetric analysis (TGA). It was used for the demulsification of two water-in-crude oil (W/O) emulsions (mwater:moil = 70:30 and mwater:moil = 10:90). The effect of PEDA concentration, settling time, demulisification temperature, pH value and salinity on the demulsifying efficiency (DE) were detailly discussed in the W/O emulsions. The results showed that the DE of PEDA could reach 91.78% and 100% in the 70:30 and 10:90 emulsion at 50 °C for 240 min, respectively. Also, PEDA had excellent acid, alkaline and salt resistance. In addition, some commercial demulsifiers were used for comparison to evaluate the demulsification ability of PEDA. The dynamic interfacial tension (IFT), three-phase contact angle (CA), zeta potential and optical microscopic observation were used to investigate the demulsifying mechanism. The current study not only develops a new PEDA demulsifier with excellent performance at lower temperature but also provides a simple synthesis method for the demulsifier using less variety of raw materials, so it is more conducive to the industrial applications.