A New Strategy for Fuel Desulfurization by Molecular Inclusion with Copper(II)-β-cyclodextrin@SiO₂@Fe₃O₄ for Removing Thiophenic Sulfides

Abstract

Developing a new and environment-friendly desulfurization strategy for removing thiophenic sulfides from fuel is currently necessary. Fuel desulfurization by molecular inclusion with a novel cyclodextrin-based magnetic nanomaterial copper(II)-β-cyclodextrin@silica@ferroferric oxide (Cu(II)-β-CD@SiO 2 @Fe 3 O 4 ) was proposed for the efficient removal of thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) in fuel. Cu(II)-β-CD@SiO 2 @Fe 3 O 4 was successfully prepared by the reaction between mono-6-O-toluenesulfonyl-Cu(II)-β-CD and 3-aminopropyltrimethoxysilane functionalized SiO 2 @Fe 3 O 4 , and the structural characterization illustrated that the active desulfurization component Cu(II)-β-CD was evenly immobilized on the surface of SiO 2 @Fe 3 O 4 . Furthermore, Cu(II)-β-CD@SiO 2 @Fe 3 O 4 showed outstanding desulfurization performance for thiophenic sulfides in the order BT > DBT > T on account of the varying molecular inclusion ability of Cu(II)β-CD for the three types of thiophenic sulfides. The optimum immobilized load of Cu(II)-β-CD in Cu(II)-β-CD@SiO 2 @Fe 3 O 4 was 5m%, and room temperature was favorable for the desulfurization process. Cu(II)-β-CD@SiO 2 @Fe 3 O 4 exhibits good regeneration performance. The inclusion interaction between Cu(II)-β-CD and sulfides plays a more dominant role than the coordination interaction of Cu(II) with sulfide and the physical absorption during the desulfurization process. The thiophenic sulfides mainly entered the hydrophobic cavity of Cu(II)-β-CD rather than be adsorbed on the surface of Cu(II)-β-CD@SiO 2 @ Fe 3 O 4 . The results lay the foundation of desulfurization with supramolecular magnetic materials, which is significant for environmental protection and resource saving.

Sonochemically-Promoted Preparation of Silica-Anchored Cyclodextrin Derivatives for Efficient Copper Catalysis

“…For example, Moradi et al recently stabilized Cu(II)/β-CD complexes over fibrous nanosilica and successfully employed the material as a catalyst in the synthesis of oxazolidinones [41]. Xia and co-workers prepared a magnetically-recoverable catalyst made of Cu(II)/β-CD complexes anchored over ferric oxide and covered by silica [42]. Shafiee et al reported the preparation of functionalized PEGylated mesoporous silica nanoparticle-graphene oxide as a catalyst for the synthesis of imidazoles [43].…”

Green Fuel Desulfurization with β-Cyclodextrin Aqueous Solution for Thiophenic Sulfides by Molecular Inclusion

“…However, a fluorine (F) atom existing in the CDP would cause harm to the environment, and the separation performance of the CD polymers was not satisfactory in the desulfurization process. Then a cyclodextrin-based magnetic desulfurization agent (Cu(II)−βCD@SiO 2 @Fe 3 O 4 ) 40 was developed to improve the environmental friendliness and separation performance of the CD polymers. However, the synthesis process was cumbersome, and a large amount of organic solvent was used.…”