Investigation of the Effects of Functional Groups on the Inhibition Performances of Imidazolium-Based Bola-Form Ionic Liquids as Novel High-Performance Shale Inhibitors

Ionic liquids (ILs) are consideredeffective additives to inhibitshale hydration swelling in recent years. The imidazolium-based bola-formionic liquids (IBFILs) with two positively charged groups and optimalalkyl chain lengths can greatly enhance their electrostatic interactionwith clay to improve their inhibition ability. The present study furtherextends our previous research on IBFILs to investigate the effectsof different modified functional groups on the inhibition propertiesof three novel IBFILs including [C-6(BIM)(2)]Br-2, [C-6(NBIM)(2)]Br-2, and [C-6(ABIM)(2)]Br-2. Then, their inhibitionperformances are evaluated via immersion tests, linear swelling tests,and hot-rolling recovery tests. The inhibition properties of threenovel IBFILs are evidently improved in different degrees, especiallyfor the [C-6(ABIM)(2)]Br-2 with aminegroups. Then, the inhibition mechanisms are analyzed via contact anglemeasurements, Fourier transform infrared spectrometer (FTIR), X-raydiffraction (XRD), particle size distribution measurement, & zeta;-potential,and molecular electrostatic potential (MEP) distribution. The resultsreveal that the hydrogen bonding and protonation of amine groups shouldbe responsible for the outstanding inhibition property of [C-6(ABIM)(2)]Br-2, whereas the nitro groups indirectlyhinder the coverage of the benzene rings at the clay surface to partiallyaffect the inhibition capacity of [C-6(NBIM)(2)]Br-2. Finally, the proposed mechanisms are further confirmedby molecular dynamics simulations. Our work may provide novel insightinto the development and design of efficient IL inhibitors with modifiedfunctional groups.

Automated summary

Ionic liquids (ILs) have been proven to be effective additives for inhibiting shale hydration swelling. Imidazolium-based bola-form ionic liquids (IBFILs) with modified functional groups can greatly enhance their inhibition ability. The study investigated the effect of different modified functional groups on the inhibition properties of three novel IBFILs and analyzed the inhibition mechanisms through various tests and measurements. The results provide insights into the design and development of efficient IL inhibitors with modified functional groups.