Abstract: A novel solid super acid with the composition of S₂O₈^2-/ZrO₂-TiO₂ added with Ce⁴⁺ was prepared by precipitation and impregnation. Then, the solid super acid was applied to purify longifolene from heavy turpentine oil via a catalytic conversion reaction. The experimental results showed that the catalyst had high catalytic activity for the isomerization reaction. The optimum conditions for the preparation of the catalyst are as follows: concentration of (NH₄)₂S₂O₈ 1 mol/L and calcination temperature 600 ℃. With the addition of Ce⁴⁺, it can slow the components loss and improve the catalytic stability. Ce-S₂O₈^2-/ZrO₂-TiO₂ has the best catalytic activity when the mass fraction of CeO₂ is 2%. The optimum conditions for the conversion of heavy turpentine are as follows: ratio of solid super acid to heavy turpentine in mass 3.5%, conversion temperature 150 ℃ and reaction time 4 h. The conversion ratio of caryophyllene is 99.1%. And from the product, longifolene was prepared through rectification in purities (GC) of 80%, 85% and 90%, respectively.

Key words: solid super acid, heavy turpentine, catalytic conversion, longifolene