A novel ionic liquid, 1-butyl-1H-imidazol-1-ium 3-carboxy-2-((2-carboxylatoethyl)thio)propanoate ([Bhim]CETSA), was synthesized as an environmentally friendly and efficient corrosion inhibitor, and its corrosion inhibition performance on A3 steel in 1 M HCl solution was investigated by using the weight loss method, and the results indicated that the inhibition efficiency reached up to 90.11% when the concentration of [Bhim]CETSA was 10 mM at 298 K. There was a synergistic effect between anion and cation, and the anion played a major role in the corrosion inhibition of [Bhim]CETSA. The adsorption of ionic liquid on the A3 steel surface followed a Langmuir adsorption model and was proved by using infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the relevant thermodynamic parameters were calculated and discussed. Moreover, the existence of the hydrophobic film on the A3 steel was proven by contact angle measurement, and the corrosion inhibition mechanism of [Bhim]CETSA was further studied by quantum chemical calculation.

In this work, we synthesized an ionic liquid (IL)—(Dimethylamino)ethyl Methacrylate maleate ([DMAEMA]MA) as the crosslinker, through one-pot to synthesized hydrogels with high adsorption capacity for dye in water. Both anionic dyes (methylene blue, rhodamine B) and cationic dyes (congo red, eosin B) could be adsorbed by this type of hydrogel with different adsorption mechanism, and its adsorption capacity for methylene blue (MB), rhodamine B (RHB), congo red (CR), eosin B (EB) were 489.1, 463.2, 465.5 and 462 mg/g (amount of dye adsorbed per gram of hydrogel), respectively. The surface structure of the hydrogel before and after adsorption was observed and compared by scanning electron microscope (SEM). After studying the adsorption isotherms of the hydrogel adsorbent, it was found that the hydrogel adsorbent had two adsorption mechanisms. This was not found in reported literatures previously.

A several of basic ionic liquids (ILs) were synthesized as green solvents and catalysts for the preparation of 1,8-naphthyridyl derivatives via the Friedlander reaction. [Bmmim][Im] exhibited remarkable catalytic activity to achieve the synthetic targets, and the reaction conditions were optimized. The model product 2,3-diphenyl-1,8-naphthyridine (1,8-Nap), with carboxyethylthiosuccinic acid (CETSA) to form an IL corrosion inhibitor ([1,8-Nap][CETSA]), and its corrosion inhibition performance for Q235 steel in 1 M HCl were researched by weight loss measurements, and the results showed that the inhibition efficiency was 96.95% when the concentration of [1,8-Nap][CETSA] was 1 mM at 35 °C. The electrochemical test verified that [1,8-Nap][CETSA] acted as a mixed-type inhibitor but mainly exhibited cathodic behavior. The inhibitor adsorbed on the metal surface was further proved by surface topography analysis.

Palladium nanoparticles (Pd NPs) generated in situ and stabilized by quaternary ammonium salts were used in three-component coupling reaction as the catalyst. Cations and anions of quaternary ammonium salts influenced the catalytic activity of Pd NPs, and tetrabutyl-ammonium bromide (TBAB) proved to be the best stabilizer. (2.23 ± 0.58) nm-sized Pd NPs showed the best catalytic activity under the molar ratio 1/30 [Pd(acac)₂/TBAB]. The mercury poisoning test demonstrated the reaction occurred on the surface of Pd NPs. Pd NPs could be recycled for four times without significant loss in catalytic activity.