Heteroatomic compounds in fluid catalytic cracking(FCC)diesel are generally removed by hydrogenation at high temperature and high pressure.In this study,zirconium tetrachloride(ZrCl4)based complexation was used to remove heteroatomic compounds from FCC diesel under mild conditions.Under the conditions of 90 ℃,atmospheric pressure,and cyclohexane as the reaction solvent,ZrCl4 was used to complex with FCC diesel to obtain the fractions of heteroatomic compounds such as nitrogen and oxygen compounds.Then the ZrCl4 enriched fractions were further separated by solid phase extraction(SPE)and subdivided into SPE separated fractions.Gas chromatography-nitrogen chemiluminescence detector(GC-NCD)and gas chromatography-mass spectrometry(GC-MS)were used to analyze and characterize the FCC diesel,ZrCl4 enriched fractions,and SPE separated fractions.Further,quantum chemistry calculation was employed to study the mechanism of heteroatomic compounds removal by complexation.The results show that the removal rates of total nitrogen,basic nitrogen,and non-basic nitrogen in FCC diesel by complexation with ZrCl4 are 75.9％,83.1％and 75.1％,respectively.This method has a good removal effect on basic nitrogen compounds such as anilines,non-basic nitrogen compounds such as carbazoles,and oxygen compounds such as perinaphthenone in FCC diesel,and almost no removal effect on thiophene compounds.The removal mechanism is that ZrCl4 undergoes selective complexation reactions with heteroatomic compounds such as basic nitrogen,non-basic nitrogen,and ketone,thus forming complexation precipitates with poor solubility to be separated from the diesel system.This method for removing heteroatoms has the advantages of high heteroatom removal ratio,high diesel yield,mild reaction conditions,and simple operation steps.
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