Abstract: Diels-Alder reaction between β-myrcene and maleic anhydride catalyzed by SO₄^2-/TiO₂-ZrO₂ solid superacid was investigated. By using GC, GC-MS and IR, main product in this reaction is confirmed to be 4-(4-methyl-3-pentenyl)-4-cyclohexene-1,2-dicarboxylic anhydride. The result shows that this catalyst has high catalytic activity and good selectivity to the Diels-Alder reaction between β-myrcene and maleic anhydride. The effects of catalyst to its catalytic activity are investigated. The result also shows that the optimum conditions for the preparation of SO₄^2-/TiO₂-ZrO₂ catalysts are as follows: n(Ti):n(Zr) 1:1, calcination temperature at 450℃. Under these conditions, the optimum conditions for the Diels-Alder reaction are as follows: n(β-myrcene):n(maleic anhydride) 1:1,reaction time 4 h, reaction temperature 60℃, and the ratio of solid superacids to β-myrcene mass part 1%, the β-myrcene conversion is 96.5%, and the 4-(4-methyl-3-pentenyl)-4-cyclohexene-1,2-dicarboxylic anhydride selectivity is 94.0%, or yield is 90.7%. Furthermore, the effect of storage time of the catalysts on the reaction and the experiments on regeneration of catalysts are carried out.

Key words: Diels-Alder reaction, β-myrcene, maleic anhydride, SO₄^2-/TiO₂-ZrO₂ catalysts