Isomerization and Arylation of Oleic Acid on Anion Modified Zirconia Catalysts.

The catalytic performance of anion modified zirconia catalysts, such as sulfated zirconia (SO₄/ZrO₂) and tungstated zirconia (WO₃/ZrO₂), was evaluated for the upgrading of oleic acid (OA). In the presence of an aromatic compound, two main reactions occurred on the catalysts: the skeletal isomerization of OA and the arylation of OA with aromatics. The activity of the SO₄/ZrO₂ was more than triple of that of the WO₃/ZrO₂. At 250 °C, OA/(SO₄/ZrO₂)(wt/wt) = 5, the OA conversion and the arylation selectivity reached their maximal values and the isomerization selectivity was the lowest when the toluene to OA (toluene/OA) molar ratio was about 6. When mesitylene was used instead of toluene, the OA conversion and the arylation selectivity decreased, probably because of a steric effect. An attempt to reuse the SO₄/ZrO₂ by solvent washing after a run was not so successful, while calcination at 630 °C in air recovered the activity completely. [ABSTRACT FROM AUTHOR]