Natural Hydroxyapatite: Green Catalyst for the Synthesis of Pyrroles, Inhibitors of Corrosion

Table 4

Comparison of HAp with other catalysts for the synthesis of fully functionalized pyrrole derivatives.

Entry	Catalyst	Temperatures	Yield (%)	Reference
1	NiCl2·6H2O	Reflux	60	[11]
2	STA	Reflux	88	[13]
3	HAp	60°C	90	This work