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

Table 4 Assignments of NMR lines 1 to 17

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, OC_αH₂ 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

ISSN: 2731-3654