Application of imidazolium based ionic liquids grafted on microcrystalline cellulose as demulsifiers for water in crude oil (W/O) emulsions

Separation of water and oil from water-in-oil (W/O) emulsion before transportation and refining is very important and critical. Ionic liquids (ILs) and their derivatives have recently attracted much attention as efficient chemical agents for breaking emulsions. So, here, a series of microcrystalline cellulose (MCC) grafted with imidazolium-based ionic liquids (IM-ILs) were synthesized, named as MCC@IM-ILs, and evaluated as eco-friendly surface-active agents for the separation of water from the crude oil. Structure of the synthesized com-pounds was confirmed by different characterization techniques. Dehydration efficiency percent (DE%) of the synthesized demulsifiers was measured and compared with each other. Synthesized MCC@IM-ILs showed an acceptable DE% to demulsify three kinds of W/O emulsions with different water content after 5 min. Concen-tration, alkyl chain length, and counter-anion of the synthesized MCC@IM-ILs play a key role in separating water from crude oil. Demulsifier with C10 alkyl chain length showed better DE% than the corresponding demulsifier with C6 alkyl chain length in the W/O (30:70 v/v) emulsion. Also, demulsifier with Br counter anion showed lower DE% than the corresponding BF4 ion-exchanged compound with higher hydrophilicity. Synthesized demulsifiers immobilized on ILs have significant advantages compared to unsupported ILs due to the use of green and economical cellulosic substrate.

Automated summary

The separation of water and oil from water-in-oil emulsion is crucial for its transportation and refining. Ionic liquids and their derivatives have been studied as effective agents for breaking emulsions. In this study, microcrystalline cellulose grafted with imidazolium-based ionic liquids (MCC@IM-ILs) was synthesized and evaluated as eco-friendly surface-active agents for water separation from crude oil. The structure of the synthesized compounds was confirmed through various characterization techniques. MCC@IM-ILs showed acceptable dehydration efficiency to demulsify different water-in-oil emulsions. The concentration, alkyl chain length, and counter-anion of MCC@IM-ILs played a key role in the separation process.