Table 6.

Performance of niobium-based catalysts for conversion of xylose into furfural—from 2010 to date.

Entry	Catalyst	Solvent	t (h)	T (°C)	C (%)	S (%)	Y (%)	Experimental Conditions	Ref.
1	Amorphous Nb2O5	water/toluene	3	120	93	48	45	0.10 g catalyst; 0.075 g xylose; 2 mL water + 3 mL toluene.	[174]
2	Nb2O5	water/toluene	1.5	170	90	56	50	0.05 g catalyst; 0.15 g xylose; 1.5 mL water + 3.5 mL toluene. 600 rpm.	[175]
3	Nb2O5	water/toluene	3	120	97	81	79	0.10 g catalyst; 0.075 g xylose; 2 mL water + 3 mL toluene.	[167]
4	Nb2O5	water/THF	2	130	95	47	45	0.04 g catalyst; 0.12 g xylose; THF/water ratio = 4.	[176]
5	Nb2O5 nanowires	DMSO	2	120	90	82	74	0.01 g catalyst; 0.1 g xylose; 20 mL DMSO	[177]
6	Niobic acid/niobium phosphate	water	0.5	160	44	75	33	1 g catalyst; 2 wt% xylose	[163]
7	Nb-SBA-15	water/toluene	24	160	85	93	79	4 g catalyst; 20 g L−1 xylose; water/toluene volume ratio = 1.	[182]
8	MCM-41-supported niobium oxide	water/toluene	1.67	190	83	55	46	0.05 g catalyst; 0.15 g xylose; 1.5 mL water + 3.5 mL toluene; 1000 rpm. NaCl increases the furfural yield to 60% at 170 °C after 3 h reaction.	[179]
9	H3PO4 treated Niobium phosphate	water/toluene	1	160	52	43	23	0.14 g catalyst; 2.0 g xylose; 18 mL water + 30 mL toluene.	[183]
10	Nb2O5/TiO2	H2O/GVL	-	130	98	30	29	0.02 M xylose in H2O/GVL = 1:9 v/v, 0.1–0.4 mL min−1, residence time = 106 s.	[178]