Evaluation of the efficiency of ion exchange zeolite catalysts in the preparation of xanthenes^a.

Test number	Catalyst	Weight percent (%) of selected metal	Yield (percentage)
1	Cu/NaY	3.91	98
2	Co/NaY	3.88	57
3	Ni/NaY	3.90	40
4	Mn/NaY	3.81	47

^aReaction conditions: 2 mmol of dimedone, 1 mmol of benzaldehyde and 2 mg of catalyst, 110 °C.