Table 1. Imine Condensation between 4′-Fluoroacetophenone and Benzylamine^a.

entry	catalysta	product (%)b
1	no catalyst	17
2	Zr-EDB fcu	22
3	GUF-14 hxl	14
4	GUF-14 hns	78
5c	GUF-14 hns (recycled)	75
6d	GUF-14 hns (recycled ×2)	75
7e	GUF-14 hns (5 h, filtered)	26
8f	GUF-14 hns (filtered, +19 h)	25

^aReaction conditions: 4′-fluoroacetophenone (1 mmol), benzylamine (1.3 mmol), 1-methylnaphthalene (0.5 mmol) and activated catalyst (1 mol % of Zr-EDB fcu or 0.5 mol % of acid washed GUF-14 hxl or hns) added to 3 mL of toluene and heated at 363 K for 24 h.

^bConversion determined by ¹⁹F{¹H} NMR spectroscopy.

^cMol % of recovered GUF-14 hns restored to 0.5 mmol % with 0.5–0.9 mg fresh or recycled catalyst to account for material lost during centrifugation, washing and activation procedure.

^dThe recovery process was repeated a second time.

^eReaction stopped after 5 h and filtered.

^fFiltered supernatant reacted for further 19 h.