Synthesis of tetraoctyl pyromellitate on solid superacid SO₄^2-/TiO₂-Al₂O₃

Synthesis of tetraoctyl pyromellitate from pyromellitic dianhydride and isooctyl alcohol on solid super acid catalyst SO₄/^2-/TiO₂-Al₂O ₃ was investigated. Preparation conditions of the catalyst and calcination temperature affected catalytic performance of SO₄/^2-/TiO₂-Al₂O ₃. The optimum preparation conditions were n(Ti)/n(Al) = 1:0.3, concentration of H₂SO₄ 0.5 mole/L, and calcination temperature 673 K. Optimum reaction conditions were obtained: catalyst content (1.8%), reaction time 3 hr, and n(isooctyl alcohol)/n(pyromellitic dianhydride) = 7:1. Conversion of pyromellitic dianhydride could reach 99.60% and activity of catalyst still kept at 96.50% after being used seven times. Selectivity of catalyst was good.