Preparation And Hydrodesulfurization Activity Of 4,6-Dimethyldibenzothiophene Over Ni₂P Catalysts Supported On Hierarchical Y Zeolites

Reducing sulfur content in fuels to lower than 10 ppm is one way to resolve the environmental problem,which means complete removal of highly refractory sulfur-containing molecular such as 4,6-dimethyldibenzothiophene?4,6-DMDBT?with alkyl groups adjacent to sulfur atom is really urgent.However,industrial hydrodesulfurization?HDS?process loaded transition metal sulfide catalysts couldn't satisfy the demand of state V standard.Therefore,more efficient HDS catalysts should be developed.This research forcus on the performance of the HDS of 4,6-DMDBT on the Ni₂P catalysts carried on hierarchical Y zeolites.First,nano Y zeolite with the average crystal size of 35 nm and external surface area of 126 m2/g was synthesized in the inorganic system.Supported Ni₂P catalyst with small particle size was prepared by low-temperature program reduction,which shows higher activity than CoMoS/Al2O3 catalyst toward HDS of 4,6-DMDBT.Then,Ni₂P catalyst carried on hierarchical Y zeolite prepared by using TPOAC as template catalyze 4,6-DMDBT with a conversion of 81.6%,which is caused by larger Ni₂P particle size compared with the former catalyst.The reaction product containing isomerization product and a bound of cracking products due to the strong acidity of the zeolite.Finally,other hierarchical zeolites were synthesized by the post-synthetic method which combined acid pretreatment and base leaching in the presence of CTAB.The concentration of citric acid has great influence on the structure of the final products,which is the higher citric concentration could damage the crystal structure more deeply.The conversion of 4,6-DMDBT on Ni₂P/0.1 MCA and Ni₂P/0.2 MCA were 96.2%and 94.7%separately,the reason is that large external surface area is beneficial to high dispersion.