Table 2 Concentration of by-products in solutions after high-pressure pretreatment of different types of biomass
Pretreatment conditions | Type of biomass | Type of solvent used for the pretreatment | Concentration of by-products in the solution after biomass pretreatment [mg/L] | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
5-HMF | Furfural | 1,2-dihydrobenzene | 4-hydroxybenzoic acid | Vanillic acid | Sinapyl alcohol | Guaiacol | Syringaldehyde | Furoic acid | |||
156 PSI, 60 min., 600 W | Pine chips | H2O |  < LOD |  < LOD | 0.00 ± 0.00 | 0.00 ± 0.00 | 8.79 a ± 2.17 | 0.00 ± 0.00 | 0.00 ± 0.00 | 5.38 a ± 0.51 | 0.00 ± 0.00 |
40% w/v NaCS | 4162.15 a ± 7.88 | 1340.06 a ± 4.13 | 0.00 ± 0.00 | 0.00 ± 0.00 | 185.72 b ± 0.17 | 3.01 a ± 0.60 | 9.62 ac ± 0.11 | 55.71 b ± 0.33 |  < LOD | ||
1% w/v NaOH |  < LOD | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 | 1.87 a ± 0.14 | 2.96 a ± 0.61 | 63.53 b ± 1.87 | 72.32 c ± 2.51 | 0.00 ± 0.00 | ||
60% v/v EtOH  + 1% v/v H2SO4 | 623.10 b ± 13.05 | 1553.63 b ± 2.65 | 0.00 ± 0.00 | 0.00 ± 0.00 | 232.63 c ± 7.61 | 5274.31 b ± 6.32 | 14.01 c ± 0.07 | 40.47 d ± 0.40 |  < LOD | ||
Beech chips | H2O |  < LOD |  < LOD | 0.00 ± 0.00 | 0.00 ± 0.00 | 9.79 a ± 0.20 | 0.00 ± 0.00 | 0.00 ± 0.00 |  < LOD | 0.00 ± 0.00 | |
40% w/v NaCS | 961.83 c ± 2.12 | 3475.10 c ± 5.73 | 53.62 a ± 0.41 | 23.90 a ± 0.44 | 411.34 d ± 2.44 | 132.54 c ± 0.04 | 57.50 d ± 0.77 | 20.39 e ± 0.06 |  < LOD | ||
1% w/v NaOH | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 |  < LOD |  < LOD | 131.95 c ± 7.83 | 60.69 bd ± 2.63 | 30.35 f ± 1.85 | 24.31 a ± 1.37 | ||
60% v/v EtOH  + 1% v/v H2SO4 | 433.41 d ± 18.33 | 5945.93 d ± 9.97 | 7.15 b ± 0.54 | 2.55 b ± 0.39 | 394.84 e ± 3.56 | 5251.73 b ± 5.53 | 12.61 c ± 0.31 | 10.99 g ± 0.96 | 0.46 b ± 0.10 | ||
Wheat straw | H2O | 294.00 e ± 20.25 | 1089.59 e ± 0.33 | 0.00 ± 0.00 |  < LOD | 103.17 f ± 4.65 | 0.00 ± 0.00 | 7.38 a ± 0.04 | 19.36 e ± 0.52 | 4.71 c ± 0.11 | |
40% w/v NaCS | 1344.61 f ± 43.44 | 1223.45 f ± 07.49 | 91.49 c ± 1.00 | 24.04 a ± 0.74 | 210.67 g ± 0.77 | 65.04 d ± 1.85 | 42.44 e ± 1.14 | 33.93 h ± 1.89 |  < LOD | ||
1% w/v NaOH | 0.00 ± 0.00 |  < LOD | 0.00 ± 0.00 |  < LOD | 5.21 a ± 0.02 | 90.22 e ± 1.80 | 72.59 f ± 1.49 | 36.58 h ± 0.84 | 112.68 d ± 1.69 | ||
60% v/v EtOH  + 1% v/v H2SO4 | 51.47 g ± 0.30 | 6289.71 g ± 7.50 | 0.00 ± 0.00 |  < LOD | 163.85 h ± 0.72 | 3525.08 f ± 17.72 | 21.75 g ± 0.17 | 18.97 e ± 0.38 | 0.00 ± 0.00 | ||