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Table 4 Assignments of NMR lines 1 to 17

From: Effects of pretreatment on morphology, chemical composition and enzymatic digestibility of eucalyptus bark: a potentially valuable source of fermentable sugars for biofuel production – part 1

Line number Chemical group 13C chemical shift [ppm]
1 CH3 in acetyl groups of hemicelluloses 22
2 Aryl methoxyl carbons of lignin 56
3 C6 carbon of non-crystalline cellulose 63
4 C6 carbon of crystalline cellulose 65
5 C2,3,5 of cellulose, OCαH2 carbons lignin 73
6 C2,3,5 of cellulose and hemicelluloses 75
7 C4 carbon of non-crystalline cellulose 84
8 C4 carbon of crystalline cellulose 88
9 Shoulder of C1 carbon of hemicelluloses 102
10 C1 carbon of cellulose 105
11 C2 and C6 aromatic carbons of syringyl and C5 and C6 aromatic carbons of guaiacyl in lignin 110-115
12 C2 of aromatic carbons guaiacyl in lignin 127
13 C1 and C4 aromatic carbons of syringyl (e) and (ne) 136
14 C3 and C5 aromatic carbons of syringyl (ne) and C1 and C4 aromatic carbons of guaiacyl in lignin 148
15 C3 and C5 aromatic carbons of syringyl (e) in lignin 154
16 Carboxyl groups of lignin 163-180
17 Carboxyl groups of hemicelluloses 174