from Miscanthus Cellulose - Lignin

Transcription

1 Characterizing Lignocellulosics from Miscanthus Cellulose - Lignin Poulomi Sannigrahi A.J. Ragauskas School of Chemistry and Biochemistry Georgia Institute of Technology

2 Agro-energy gy feedstock: Miscanthus Perennial crop Grows to ft in height/year High biomass yields C4 grass with high rate of carbon fixation tons/acre (up to 27 tons/acre in trials) Crop stands survive years without significant loss in biomass yields Presently used in Europe for power and heat generation 2

3 Moisture and Ash content Moisture content of air dried miscanthus sawdust (6 mm) 4.6% Ash content Measured ed by ramped heating to 525 C in a muffle furnace 2.2% 2% Higher than Loblolly pine (0.2 %) & sweetgum (0.8 %) 3

4 Elemental analysis Measured on 0.05 mm ground samples using elemental micro analyzer Miscanthus Sweetgum Loblolly Pine Wt.% C H O N

5 Inorganic elements Analyzed in 6 mm ground samples Acid digestion followed by ICP-emission spectroscopy Coulometric method for total halogen (Cl+Br+I) 5

6 Inorganic elements 6 Co ontent (mg/kg) o.d. weight Miscanthus Sweetgum L.Pine Ba Cu Fe Na P Si

7 Inorganic elements Conte ent (mg/kg ove en dried weig ght) Miscanthus Sweetgum L.Pine Ca K Mg S Mn Cl+Br+I

8 Acid soluble and insoluble lignin Klason lignin Acid idinsoluble lbl lignin i isolated ltdusing NREL methods thd Extractive free (40 mesh) sample hydrolyzed using 72 %HSO % H 2 SO 4 Acid soluble lignin Measured using UV-vis spectrophotometer Calculated from absorption at 205 nm 8

9 Lignin content and composition Klason lignin Miscanthus: 25 % Loblolly pine: 29 % Sweetgum: 26 % Aid Acid soluble lbl lignini Miscanthus: 1.1 % Loblolly pine: 0.5 % Sweetgum: 26% O O O 3 4 Guaiacyl Syringyl p-coumaryl SW x x HW x x x Grass x x x 9

10 Carbohydrate analysis 40 mesh extractive free wood Hydrolyzed y with 72 % H 2 SO 4 Diluted to 3% H 2 SO 4 and autoclaved at 121 C for 1 hour Sugars measured using HPLC with pulsed amperometric detector 10

11 Carbohydrate profile HO O tarting mat terial % dry weight of s HO O HO 2 O O Miscanthus Sweetgum L.Pine 2 O Arabinose Galactose Glucose Xylose Mannose

12 Solid-state 13 C NMR of miscanthus Lignin C=O Lignin Phenolic Cellulose Lignin -O 3 Hemicellulose R-CO 3 12

13 Cellulose extraction Holocellulose = Cellulose + Hemicellulose Obtained by treating extractive free wood repeatedly with acetic acid and sodium chlorite Yield: 74% (by dry wt. of miscanthus) Cellulose Boil holocellulose with 2.5 M HCl at 100 CC for 4 hours Yield: 55% (by dry wt. of holocellulose) 13

14 Cellulose structure and crystallinity y Solid-state 13 C CP/MAS NMR of cellulose Cellulose structure and crystallinity O O 2 1 O 2 O 1 C2,3,5 C1 C4 C6 14

15 Cellulose structure and crystallinity y Degree of crystallinity : 48.9 % Loblolly pine:63 %; Sweetgum: 53.3% 3% Crystalline + para crystalline Amorphous 15

16 Milled wood lignin Purest form of lignin that can be isolated Wood extracted with ethanol and ethanol/benzene Milled for 130 hours Extracted with 96% Dioxane for 48 hours Dioxane collected, dried and lignin purified 16

17 Milled wood lignin 13 C NMR O O 4 O 3 4 Guaiacyl (g) Syringyl (s) p-coumaryl (h) 2 3 -O 3 h-4 s and g 4-O-5 α-co/ β-o-4 β-5 COOR 17

18 Lignin molecular weight Lignin acetylated and Mn Mw D dissolved in THF Molecular weight distribution measured using gel permeation chromatography h Miscanthus 8.33e e Sweetgum 9.41e 3 1.6e L.Pine 7.58e e

19 Thank You! 19