Deep Extraction Desulfurization with a Novel Guanidinium-Based Strong Magnetic Room-Temperature Ionic Liquid

Abstract

A series of novel guanidinium-based magnetic ionic liquids were synthesized. Among them, [TMG]Cl/1.5FeCl3 exhibited a very strong paramagnetic strength with the value of magnetic susceptibility as great as 59.1 × 10–6 emu/g, which exceeded any other reported magnetic IL so far. By virtue of good physical and chemical properties, it was representatively selected to extract dibenzothiophene (DBT) and thiophene (T) from model oils with sulfur content of 900–1000 μg/g, which was compared with commonly reported imidazolium magnetic ionic liquid [BMIM]Br/1.5FeCl3. The results revealed that [TMG]Cl/1.5FeCl3 had perfect desulfurization efficiency (nearly 100%) with mass ratio of oil to MIL (g/g) of 1–4 within only 5 min at room temperature, and the method could easily meet the latest European sulfur emission standard (Euro 5). It showed significant selectivity for sulfur over toluene, as well as little pollution of the model oils, which were both better than [BMIM] Br/1.5FeCl3. Satisfactory desulfurization performance for 93 gasoline was further achieved by [TMG]Cl/1.5FeCl3. Furthermore, it could be recycled at least 7 times without any noticeable decrease in desulfurization efficiency. The novel MIL demonstrates promise in practical application in the future.