Synthesis Of Pyrrolidinium Polymolybdates And Their Application In Desulfurization Of Oil

Sulfur compound in fuels has been recognized as a major source of sulfur oxides which contributes to air pollution.In order to decrease the emission of sulfur oxides from the utilization of sulfur-containing fuel oils,many stringent environment legislations have been issued to limit the sulfur content of fuels.Oxidative desulfurization(ODS)combined with extraction is one of the most promising desulfurization processes,which can be performed at very mild conditions as ambient temperature and atmospheric pressure.Developing much higher efficient catalysts for ODS is a significant project.In this paper,five polyoxomolybdates were prepared,including [C4H8NC4H9]4-Mo8O26,[C4H8NC8H17]4Mo8O26,[C4H8NC12H25]4 Mo8O26,[C4H8NC16H33]4Mo8O26 and [C4H8NC16H33]2 Mo2O11.Their structures were characterized by IR,1H NMR,ESI-MS.As we know,those five chemical compounds have not been reported.The above five polyoxomolybdates were applied to remove dibenzothiophene(DBT)in a model diesel as catalysts.The results show that the catalytic activity of [C4H8NC16H33(CH3)]4Mo8O26 and [C4H8NC16H33(CH3)]2Mo2O11 were better than that of other catalysts,the removal rates of sulfur of which could achieved above 98%.Meanwhile,the effects of volume of ionic liquid,times,O/S molar ratio and the temperature on desulfurization were investigated.The optimal reaction conditions using [C4H8NC16H33]4Mo8O26 and [C4H8NC16H33]2Mo2O11 catalysts respetively were determined.Under the optimal conditions,the efficiencies of oxidative desulfurization decreased in the order of DBT>BT>T,which was influenced by electron density on the sulfuratoms.[C4H8NC16H33(CH3)]4Mo8O26 and [C4H8NC16H33(CH3)]2Mo2O11 were applied to desulfurization of the real gasoline and lubricant base oil.The results showed that [C4H8NC16H33(CH3)]2Mo2O11 was better than [C4H8NC16H33(CH3)]4Mo8O26.[C4H8NC16H33(CH3)]2Mo2O11 reduced the sulfur content of the gasoline from 212.78 mg/L to 23.65 mg/L.Acetonitrile was more suitable to be used as extract than ionic liquid to desulfurize lubricant base oil.The sulfur content of the base oil was reduced from 500 mg/L to 161.28 mg/L in acetonitrile system.