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A highly branched PNDC demulsifier with 2,6‐naphthalenedicarboxylate as centronucleus was prepared by an efficient "one‐pot" strategy. The product was characterized by FT‐IR, 1H‐NMR, and TGA. The bottle test was performed to explore the effect of temperature, settling time, pH value, and concentration on the demulsification efficiency (DE). The DE reached an optimal value of 94.63% when the concentration of PNDC, settling time and operated temperature were 100 mg/L, 60 min and 70°C, respectively. Also, the DE could reach 91.58% when the concentration was only 20 mg/L at the same conditions. It showed that PNDC had an excellent performance in W/O emulsions with an extremely low concentration. Especially, PNDC could be used over a wide pH range (4–12) and high salinities, indicating that it had a good salt, acid and alkaline tolerance. In addition, the interfacial tension (IFT), surface tension (SFT), elastic modulus and micrograph analysis were carried out to investigate the possible mechanism. This work provides a highly branched demulsifier with high DE for the demulsification of stable W/O emulsions. [ABSTRACT FROM AUTHOR]

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• The synthesis step of the demulsifier is extremely simple. • The demulsifier has a good performance and application potential. • This work provides a new idea for explanation of demulsification mechanism. • The demulsifier can greatly shorten time and reduce temperature of demulsification. A three-branch structure demulsifier (GTE-DDA) for the treatment of water-in-crude oil (W/O) emulsions was synthesized by a one-step method using glycerol triglycidyl ether (GTE) as core and dodecyl amine (DDA) as branched chain. It was characterized by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance hydrogen spectra (1H NMR) and thermogravimetric analysis (TGA). Some key parameters such as the concentration of GTE-DDA, settling time, operated temperature and salinity on demulsification efficiency (DE) were systematically explored. The DE reached 87.55% after treating with 400 mg/L of GTE-DDA at 50 °C for 30 min. The demulsifying temperature was significantly lower than those reported in literatures (60-80℃). Especially, a rise in temperature could further improved the DE. In addition, GTE-DDA had an excellent salt tolerance. The possible mechanism was investigated by the interfacial tension (IFT), three-phase contact angle (CA) and microscopic observation. The comparison with commercial demulsifiers showed that GTE-DDA had a great potential for the treatment of crude oil emulsions. [ABSTRACT FROM AUTHOR]

Water-in-oil emulsions are frequently encountered in petroleum extraction. In this paper, CRB-SiO 2 , a cost-efficient and environmentally friendly demulsifier, was synthesized by a two-step method. The chemical structure and surface morphology were analyzed by flourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The effect of salinity, concentration, temperature and pH value on the demulsification efficiency (DE) was investigated in detail. The DE reached 93.98% with 600 mg/L of CRB-SiO 2 at 70 °C. Also, it had an excellent tolerance of salt, acid and alkali. Moreover, the demulsification mechanism was also studied through three-phase contact angle, interfacial tension and self-assembly of interfacial membrane. CRB-SiO 2 has an amphiphilic structure and lower interfacial tension (IFT) around 37.75 mN/m. Accordingly, it can be easily adsorbed at the water-oil interface, destroying the interface membrane and initiating the separation of oil and water. In summary, CRB-SiO 2 has a potential application in petrochemical industry. [Display omitted] • CRB-SiO 2 was prepared by a two-step method. • CRB-SiO 2 has high demulsification efficiency in water-in-crude oil emulsion. • CRB-SiO 2 is environmentally friendly and highly economical because it uses waste rice bran as raw material. • CRB-SiO 2 has an excellent tolerance of salt, acid and alkali. • The demulsification mechanism has been deeply studied from many aspects. [ABSTRACT FROM AUTHOR]