Table 8. Influence of the Reused 10% Pd/C Catalyst on the Ratio of Byproducts in the Hydrogenation of PPN^a.

			composition of byproduct
no.	reusing the catalyst	purity of PPA (%)	PPN (%)	TPPA (%)	BPPA (%)	PPAL (%)	PPOH (%)
1	-(fresh)	99.0	29.9	68.3	0	1.3	0.5
2	1st	69.6	66.0	26.3	0	7.6	0.1
3	-(fresh)b	99.8	33.5	64.6	0	1.3	0.6
4	1stb	99.7	32.5	65.8	0	1.2	0.5

^aConditions: 5.0 g (38.2 mmol) PPN, 1.5 g 10% Pd/C (Selcat Q) catalyst, 250 mL of water and 50 mL dichloromethane, 5.27 g NaH₂PO₄·H₂O (38.2 mmol), and 3.82 g conc. H₂SO₄ (38.2 mmol), 80 °C, 6 bar, reaction time: 7 h.

^b10% Pd/C catalyst was prehydrogenated in 200 mL water, at 30 °C and 6 bar, for 0.5 h.