Zirconyl (IV) Nitrate as Efficient and Reusable Solid Lewis Acid Catalyst for the Synthesis of Benzimidazole Derivatives

Table 3

Catalyst reusability study for the reaction of benzaldehyde with o-phenylenediamine^a.

Entry	Yield^b(%)	Catalyst recovery (%)
1	96	97
2	93	94
3	90	92
4	88	91

aReaction condition: benzaldehyde (1 mmol), o-phenylenediamine (1 mmol), ZrO(NO₃)₂ (0.5 wt.%), ethanol, reflux. bIsolated yield.