Table 1.
The catalytic production of furfural from biomass using homogeneous catalysts.
| Catalyst | Solvent | Reaction Conditions | Substrate Loading | Yield | Selectivity | Ref. |
|---|---|---|---|---|---|---|
| Mineral acids | ||||||
| H2SO4, 50 mM | NaCl, 3.5 wt% | 200 °C, 10 min | Xylose, 35 mM | 75% | 83% | [38] |
| HCl, 50 mM | NaCl, 5.0 wt% | 200 °C, 8 min | Xylose, 35 mM | 81% | 90% | [38] |
| HCl, pH = 1.12 | H2O | 180 °C, 20 min | Xylan, 1 wt% | 34% | - | [39] |
| H2SO4, pH = 1.12 | H2O | 180 °C, 20 min | Xylan, 1 wt% | 29% | - | [39] |
| HNO3, pH = 1.12 | H2O | 180 °C, 20 min | Xylan, 1 wt% | 29% | - | [39] |
| H3PO4, pH = 1.12 | H2O | 180 °C, 20 min | Xylan, 1 wt% | 26% | - | [39] |
| H2SO4, 0.25 wt% | H2O | 240 °C | Wood chip pre-hydrolysate | 76% | 80% | [40] |
| H2SO3, 0.25 wt% | H2O | 240 °C | Wood chip pre-hydrolysate | 54% | 54% | [40] |
| H2SO4, 50 mM | H2O/MIBK (v/v = 1/2) | 170 °C, 20 min Microwave | Pentose-rich corn stover hydrolyzate, 8 wt% | 80% | 86% | [41] |
| Organic acids | ||||||
| Maleic acid, 0.25 M | H2O | 200 °C, 28 min Microwave | Xylose, 1 wt% | 67% | 67% | [42] |
| Formic acid, 2 wt% | H2O/o-Nitrotoluene (v/v = 1/3) | 190 °C, 75 min | Xylose, 8 wt% | 74% | 86% | [43] |
| Formic acid, 62.5 g/L, betaine, 17.5 g/L | H2O-CPME (v/v = 1/3) | 170 °C, 60 min Microwave | Xylose, 37.5 g/L | 76% | 76% | [44] |
| Formic acid, 62.5 g/L, betaine, 17.5 g/L | H2O-CPME (v/v = 1/3) | 170 °C, 60 min Microwave | Xylan, 37.5 g/L | 80% | 80% | [44] |
| Inorganic salts | ||||||
| CrCl3 6 mM, HCl 0.1 M | H2O-Toluene (v/v = 1/1) | 140 °C, 120 min | Xylose, 1 wt% | 76% | 80% | [45] |
| AlCl3·6H2O, 6.025 g/L, NaCl, 21.875 g/L | H2O-THF (v/v = 1/3) | 140 °C, 45 min Microwave | Xylose, 9.375 g/L | 75% | 75% | [46] |
| AlCl3·6H2O, 6.025 g/L, NaCl, 21.875 g/L | H2O-THF (v/v = 1/3) | 160 °C, 60 min Microwave | Corn stover, 12.5 g/L | 55% | 77% | [46] |
| AlCl3·6H2O, 6.025 g/L, NaCl, 21.875 g/L | H2O-THF (v/v = 1/3) | 160 °C, 60 min Microwave | Switchgrass, 12.5 g/L | 56% | 79% | [46] |
| AlCl3·6H2O, 6.025 g/L, NaCl, 21.875 g/L | H2O-THF (v/v = 1/3) | 160 °C, 60 min Microwave | Poplar gave, 12.5 g/L | 64% | 79% | [46] |
| FeCl3 10 mol%, NaCl 100 mol% | H2O-CPME (v/v = 1/3) | 170 °C, 20 min Microwave | Xylose, 1.25 mmol | 74% | 74% | [47] |
| NaHSO4, 3.31 wt% | H2O-THF (v/v = 1/10) | 190 °C, 90 min | Corncob, 11.1 wt% | 54% | 54% | [48] |
| NaHSO4, 3.31 wt% | H2O-THF (v/v = 1/10) | 190 °C, 90 min | Bagasse, 11.1 wt% | 61% | 61% | [48] |
| Al2(SO4)3 10 mol% | H2O-GVL (v/v = 1/4) | 130 °C, 30 min | Xylan, 2 mmol | 88% | 99% | [49] |
| Ionic liquids | ||||||
| [C4SO3Hpy][BF4], 0.1 g | H2O-THF (m/m = 1/2) | 180 °C, 60 min Microwave | Xylose, 0.1 g | 85% | 89% | [50] |
| [bmim]HSO4, 1 g | Toluene, 4.4 g | 140 °C, 240 min | Xylose, 0.1 g | 74% | 74% | [51] |
| [bmim]HSO4, 0.3 g | H2O-Toluene (m/m = 1/4.4) | 140 °C, 360 min | Xylose, 0.1 g | 71% | 72% | [52] |
| [bmim]HSO4, 0.3 g | H2O-Toluene (m/m = 1/4.4) | 140 °C, 360 min | Hemicellulose, 0.1 g | 62% | - | [52] |
| [C3SO3Hmim]Cl, 0.1 M | H2O-GVL (v/v = 1/19) | 140 °C, 180 min | Xylose, 30 g/L | 78% | 82% | [53] |
| [bmim]AlCl4, 0.1 M | H2O-Butanone (v/v = 1/4) | 140 °C, 90 min | Xylose, 30 g/L | 75% | 75% | [54] |
| [bmim]Cl/AlCl3, 0.1 M | H2O-Butanone (v/v = 1/4) | 140 °C, 30 min Microwave | Arabinose, 30 g/L | 60% | 60% | [55] |