Synthisis And Properities Of New Heteropoly Acid Solid Catalysts In Hydrodesulfurization And Oxidative Desulfurization Reactions

Currently, hydrodesulfurization is the main methods of desulfurization in industry. It is a hot topic to find a catalyst capable of deep hydrodesulfurization. The mild reaction conditions of heterpoly acid catalyzed oxidation desulfurization in accordance with the requirements of environmental protection. It is an urgent problem to be solved that catalyst is difficultly separated and recycling from the reaction system. Heterpoly acid based mesoporous composites prepared in this paper can be highly active in catalytic oxidation desulfurization reation, and easy to recycling. The excellent structure of heterpoly acid based solid catalyst with high catalytic activity for gasoline deep desulfurization reaction was designed and synthesized. The concrete research content as follows:(1) Mesoporous hybrid materials(SDS-Al13/30) with Keggin structure(or double Keggin structure) aluminum cation combined with anionic surfactant were prepared, then Keggin heterpoly acid(HPA) loaded on the homemade mesoporous hybrid materials(SDS-Al13/30-HPA) by the impregnation method. Characterization results of FT-IR, XRD and Raman showed that cations and anions in the hybrid materials were Keggin type, and structural integrity. SDS-Al13/30-HPA catalytic oxidation desulfurization reaction in a model of oil(hexan solution of organic sulfur) was studied, the experimental results indicated that the SDS-Al13/30-HPA new composite materials have high catalytic activity in oxidation desulfurization. Under the optimized reaction conditions of 60 oC, n(H2O2)/n(S)=10 and catalyst accounts for 5% of cyclohexane solution quality, ethanethiol were more likely to be oxidative desulfurization than other organic sulfide(such as dibenzothiophene(DBT) and benzothiophene(BT)). The series of catalyst were easy to be separated and recycling and desulfurization efficiency was no significant decline after recycling three times.(2) HPA based solid material was prepared by HPW and Ni(II) component loaded on the extrusion moulding of nano-HZSM-5 zeolite. The catalyst metal oxide component and HPW surface state were characterized by Py-IR and ESR after H2 reduction. The catalytic performance of the new materials was evaluated using FCC gasoline hydrodesulfurization as the probe reaction. The results of FT-IR characterization confirmed that the Keggin framework of HPW was unchanged after calcination. The HPA frame structure of catalyst was not destroyed after the FCC gasoline hydrodesulfurization reaction continuing 47 h. The situ ESR of hydrogen reduction catalyst showed that Ni(II) has not been reduced to Ni(0)and W(VI) was mainly reduced to W(III) in the catalyst of HPW combined with Ni(II) after roasting and reduction at 350 o C. The appropriate amount of acid and synergy of Br?nsted and Lewis acid is the reason of activity improvement of composite solid acid catalyst in the deep hydrodesulfurization reaction.