The ortho-compound formed penta cyclic compound was more stable that the meta-compound formed hexa cyclic compound, so the reaction rate of the ortho-compound is larger.
由邻位化合物生成的五元环络合物比由间位化合物形成的六元环络合物稳定性高，反应速度快。
2
And if there is a hydroxyl in ortho position of carboxyl, the oxygen of hydroxyl and carboxyl in ligand are bound to ti to form hexatomic cyclic compound.