Study on reducing olefin of FCC gasoline in the ionic liquid system

New bi-liquid phase catalytic systems containing two different types of strong Lewis acidic ionic liquids which do not dissolve in FCC gasoline, were employed to reduce the olefin content in FCC gasoline. It was shown that the olefin content decreases by 14.70% in[bmIm]Cl-AlCl_3 ionic liquid system and 13.08% in \Cl-AlCl_3 ionic liquid system, respectively, while the octane number of gasoline does not decrease. The olefin content of FCC gasoline after dealing with the ionic liquids is less than 35%, which has reached the national usage standard for clean FCC gasoline. The mechanism of olefin reducing in FCC gasoline was investigated in detail. It was the alkylation, dimerization and Frediel-Crafts reactions catalysed by the Lewis super strong acidic ionic liquids that caused the olefin reducing in FCC gasoline.