Acylated carboxymethyl chitosan grafted with MPEG-1900 as a high-efficiency demulsifier for O/W crude oil emulsions

• Published in: Carbohydrate polymer technologies and applications Vol. 2; p. 100144
• Main Authors: Lyu, Renliang, Li, Zeqin, Liang, Cheng, Zhang, Cheng, Xia, Ting, Wu, Ming, Wang, Yi, Wang, Lichun, Luo, Xiaogang, Xu, Caili
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 25-12-2021; Elsevier
• Subjects: Acylated carboxymethyl chitosan; Demulsifier; Polyethylene glycol monomethyl ether; Surface tension; Polyethylene glycol monomethyl ether; Demulsifier; Surface tension; Acylated carboxymethyl chitosan
• ISSN: 2666-8939; 2666-8939
• DOI: 10.1016/j.carpta.2021.100144

•Three chitosan derivatives containing acyl group, carboxymethyl group and MPEG-1900 were synthesized.•The chitosan derivatives had superior demulsification ability compared with chitosan.•The chitosan derivatives could address high concentration of crude oil emulsion compare with current positive control.•The acyl group were major effect factor of demulsification efficiency.
In this work, due to its excellent adsorption performance, biodegradability, and low toxicity, chitosan was used as the raw material to synthesize a series of new oil-in-water (O/W) type crude oil demulsifiers. First, an acyl group was introduced onto the chitosan molecule. Then, sodium chloroacetate was used as a carboxymethylation reagent to introduce a carboxymethyl group into the acylated chitosan. Furthermore, polyethylene glycol monomethyl ether with an average molecular weight of 1900 (MPEG-1900) was used to react with acylated carboxymethyl chitosan to synthesize chitosan-based O/W type demulsifiers. The molecular structures of the synthetic chitosan derivatives were characterized using Fourier-transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance techniques. The results showed that the surface tension decreased with an increase in the concentration of polysaccharide demulsifiers, which included MPEG-1900-A4CMC, MPEG-1900-A6CMC, and MPEG-1900-A8CMC. The demulsification efficiency of these synthetic demulsifiers reached a maximum over 100 min at a concentration of 200 ppm at 50 °C. The as-synthesized chitosan derivatives showed good demulsification performance.