Catalytic Oxidative Desulfurization Process In Fuel Oil With Pom-based Hypercrosslinking Poly(Ionic Liquid)

Today,the production of environmentally friendly sulfur-free fuels is a global demand due to the increasing demand for ultra-clean fuels.Hydrodesulfurization is a typical oil refining technology widely used in industry but still suffers from several problems.Therefore,to overcome these problems,researchers have developed various non-hydrodesulfurization techniques such as extraction,adsorption,and oxidation,among which oxidative desulfurization has become one of the most promising techniques due to its mild reaction conditions and efficient desulfurization efficiency.In this thesis,two types of hypercrosslinked poly(ionic liquid)were synthesized by one-step polymerization and external crosslinking methods,and polyacid-based hypercrosslinked poly(ionic liquid)catalysts were obtained after the introduction of polyoxometalates(POMs).The functional group type,pore structure,and specific surface area of the catalysts,as well as the elemental composition and chemical state of the catalysts,were investigated by FT-IR,BET,and XPS characterization.The oxidation products were investigated by GC-MS and ESR analysis,and the reaction mechanism was investigated.The main studies are as follows:Firstly,a polyacid-based poly(ionic liquid)PI-DCX-8-PMA with a rich pore structure,was synthesized by a one-step polymerization method.The pore structure and specific surface area were investigated by BET characterization,and the production of phosphomolybdenum blue was demonstrated by XPS characterization.The effects of temperature,oxidant,and catalyst dosage on desulfurization performance were also investigated.The oxidation products and the reaction mechanism were investigated by GC-MS characterization.This catalyst was used in fuel oil desulfurization to achieve ultra-deep desulfurization of DBT at 0.02 g catalyst,O/S=5,and a reaction temperature of 50 ~oC,with a sulfur removal of 99.08%.Secondly,a series of super-crosslinked poly(ionic liquid)with specific surface areas ranging from 486 m~2/g to 630 m~2/g were synthesized by an external crosslinking method using 1-benzyl-3-methylimidazole chloride salt and toluene as raw materials and FDA as an external crosslinker.The PMA was introduced as the active center by means of anion exchange,resulting in a polyacid-based hypercrosslinked poly(ionic liquid)catalyst,HPIL-4-PMA,with both amphiphilic and rich pore structures,which was used for DBT removal from fuel oil,achieving 99.5%desulfurization under mild operating conditions and ultra-deep desulfurization.