Adsorptive denitrogenation of fuel over molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol microspheres

Abstract

Molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol microspheres (MIPs) were prepared by suspension polymerization of 2-(1H-imidazol-2-yl)-4-vinylphenol in the presence of nitrogen containing compounds (N-compounds). Nitrogen containing compounds such as quinoline, pyrimidine and carbazole, largely found in fuel oils, were employed as templates in MIP synthesis. Isothermal titration calorimetric (ITC) studies revealed that quinoline/2-(1H-imidazol-2-yl)-4-phenol (PIMH) and pyrimidine/2-(1H-imidazol-2-yl)-4-phenol (PIMH) interactions were exothermic (−18.0 ± 4.8 and −28.1 ± 3.6 kJ mol⁻¹, respectively), while the carbazole/2-(1H-imidazol-2-yl)-4-phenol (PIMH) interaction was endothermic (3.3 ± 0.7 kJ mol⁻¹). Imprinted microspheres show selectivity for the various target nitrogen-containing compounds in fuel oil with adsorption capacities of 10.56 mg g⁻¹, 11.71 mg g⁻¹ and 10.84 mg g⁻¹ for pyrimidine, carbazole and quinoline, respectively. The removal of other stubborn nitrogen containing compounds from fuel oil demonstrates their potential application in the field of fuel denitrogenation.