Investigation the effect of different ionic liquids based-aryl imidazole on the onset precipitation of asphaltene

Precipitation and deposition of asphaltene are considered as catastrophic issues facing the petroleum industry. Asphaltene deposition mainly occurs at variety places such as formation pore spaces, pumps, pipelines, wellbore, wellhead, tubing, surface facilities and safety valves causing operational problems, production deficiencies and enormous economic losses. This work aims to study the effect of series of synthesized aryl ionic liquids (ILs) containing different alkyl chains, named as R(8)-IL, R(10)-IL, R(12)-IL, and R(14)-IL, on the onset precipitation point of asphaltene in crude oil. R(8)-IL, R(10)-IL, R(12)-IL, and R(14)-IL were synthesized with high yields (the yield varied between 82 and 88%) and characterized via different tools of analysis (FTIR, (1)H NMR, and Elemental Analysis). Their Thermal Gravimetric Analysis (TGA) was investigated and showed a reasonable degree of stability. It was found that R(8)-IL (short alkyl chain) has the highest stability, while R(14)-IL (long alkyl chain) is the lowest one. Quantum chemical calculations were conducted to study the reactivity and geometry of their electronic structures. Moreover, surface and interfacial tension of them were studied. It was found that the efficiency of the surface active parameters increased by increasing the length of the alkyl chain. The ILs were evaluated to delay the onset precipitation point of asphaltene using to different methods; the kinematic viscosity and the refractive index. Results from the two methods showed delaying of onset precipitation after the addition of the prepared ILs. The asphaltene aggregates was dispersed due to the π–π* interactions and hydrogen bonds formation with the ILs.