Unraveling the structural characteristics of lignin in hydrothermal pretreated fibers and manufactured binderless boards from Eucalyptus grandis

Sustainable Chemical Processes

Table 1 Solid yield and chemical composition of untreated Eucalyptus globule , hydrothermal pretreated fibers, and manufactured binderless boards from Eucalyptus grandis

Entry	Label	Temperature (°C)	Residence time (h)	Solid yield	Chemical composition^a(%)
					Glu	Xyl	Gal	Ara	Rha	GlcA	KL	ASL
Control	Raw	–	–	100	43.4	18.8	1.2	0.3	0.6	1.4	28.5	3.2
1	F1-a	150	1	91.8	38.2	18.6	1.3	0.4	0.7	1.2	30.8	3.6
2	F1-b	150	1	–	42.1	17.9	1.2	0.2	1.2	1.3	27.2	3.4
3	F4-a	150	4	95.4	38.0	18.9	1.2	0.4	0.7	1.3	29.3	3.7
4	F4-b	150	4	–	42.2	18.0	1.2	0.2	0.5	1.4	26.4	3.5
5	F8-a	150	8	86.9	36.7	17.9	1.1	0.4	0.6	1.1	31.0	3.5
6	F8-b	150	8	–	43.3	18.3	1.1	0.2	0.5	1.3	27.4	3.2
7	Q1-a	160	1.5	96.6	35.9	17.2	1.2	0.5	0.7	1.1	33.0	3.2
8	Q1-b	160	1.5	–	42.5	18.0	1.1	0.3	0.6	1.2	27.5	3.1
9	Q2-a	160	3	95.8	34.8	16.7	1.3	0.6	0.7	1.0	33.2	3.1
10	Q2-b	160	3	–	41.1	17.2	1.1	0.3	0.5	1.2	28.0	3.0
11	Q3-a	160	4.5	95.6	36.8	17.2	1.2	0.5	0.6	1.1	32.5	3.4
12	Q3-b	160	4.5	–	41.2	17.3	1.1	0.2	0.5	1.1	28.7	3.0
13	Q4-a	160	6	97.0	34.8	16.7	1.3	0.6	0.7	1.2	33.1	3.2
14	Q4-b	160	6	–	42.3	19.1	1.2	0.2	0.6	1.3	28.2	3.1

^aCalculated on basis of the raw material (w/w%). All the measurements were obtained in triplicate, and the mean value has been indicated. Glu, Glucan; Xyl, Xylan; Gal, Galactan; Ara, Arabian; Rha, Rhamnan; GlcA, Glucuronic acid; KL, Klason lignin; ASL, Acid-soluble lignin.