Comparison of the catalytic efficiency of Fe₃O₄/SO₃H@zeolite-Y with other catalysts for the synthesis of imidazoles (entries 1–8) and perimidines (entries 9–16) for their model reactions (1 mmol from the raw materials).

Entry	Catalyst/conditions	Time (h)	Yielda (%)
1	Fe3O4g-C3N4 (0.02 g), EtOH, 78 °C	2	95 (ref. 41)
2	Fe3O4@chitosan (0.05 g), EtOH, reflux	2	95 (ref. 42)
3	Benzethonium chloride (10 mole%), EtOH : H2O, 70 °C	0.75	95 (ref. 43)
4	Sodium dodecyl-sulfate (0.02 g), H2O, 80 °C	1	90 (ref. 44)
5	Fe3O4@SiO2·HM·SO3H (0.04 g), solvent-free, 110 °C	0.25	93 (ref. 37)
6	Fe3O4@SiO2·HM·SO3H (0.060 g), solvent-free, MWI	0.13	77 (ref. 45)
7	Sulfamic acid-Fe3O4 NPs (0.1 g), EtOH, reflux	2	90 (ref. 46)
8	Fe3O4/SO3H@zeolite-Y (0.02 g), EtOH, 80 °C	0.75	98 (this work)
9	CuY-zeolite (0.002 g), EtOH, rt	0.42	81 (ref. 20)
10	NaY zeolite (0.2 g), EtOH, rt	45–50	70 (ref. 47)
11	FePO4 (10 mol%), EtOH, rt	0.22	80 (ref. 48)
12	Ytterbium(iii) trifluoromethanesulfonate (0.1 equiv.), MeCN, rt	24	88 (ref. 49)
13	Fe3O4/SiO2/(CH2)3N+Me3Br3− (0.007), solvent-free, 80 °C	12	93 (ref. 50)
14	Nano-γ-Al2O3/SbCl5 (0.1 g), solvent-free, rt	0.25	95 (ref. 21)
15	Cu(NO3)2 (5 mole%), 2H2O, EtOH, rt	0.17	83 (ref. 51)
16	Fe3O4/SO3H@zeolite-Y (0.008 g), EtOH, rt	0.07	98 (this work)

^aIsolated yield.