Lignin Structure and Applications. Göran Gellerstedt

Transcription

1 Lignin Structure and Applications Göran Gellerstedt

2 H 3 C H 3 C H H H H 3 C H 3 C CH 2 CH 2 CH 2 H 3 C H CH 3 H 3 C H CH 3 H 3 C CH 3 CH H 3 C 3 H 3 C H 3 C 1CH CH 2 H 3 C Lignin structure Lignin H Lignin Plant Type p-coumaryl alcohol Coniferyl alcohol Sinapyl alcohol H H 3 C H CH H 3 H H H 3 C H 3 C H Per cent CH 3 H H H 3 C Coniferous; Softwoods <5 >95 0 H Eudocotyledonous; Hardwoods H 3 C H H 3 C Monocotyledonous; Grasses CH 3 H 3 C H 3 C H 3 C H Lignin CH

3 Lignin content in plants Plant Lignin Content Scientific/Common Name Gymnosperms Picea abies, Norway spruce " (compression wood) Pinus sylvestris, Scots pine Angiosperms - Eudicotyledons Betula verrucosa, Siver birch Eucalyptus globulus, Blue gum eucalyptus Populus tremula, European aspen Angiosperms - Monocotyledons Saccharum species, Bagasse

4 From biomass to liquid fuels in 2020 ( Mtoe within EU) Biodiesel Pulp 4 (+9) Mtoe 13 (+1) Mtoe Lignin 11 Mtoe DME, FT-diesel Ethanol 5 Mtoe Hemicell.

5 Current Biorefinery Activities (EU) EuroBioRef 37.4 M suprabio 19.0 M Biocore 20.3 M Biomass Processing Lignin Processing surfactants emulsifiers antioxidants CIMV-process Lignin resins, adhesives,

6 Suggested uses for lignin Fragmentation Phenols Vanillin rg. S-comp. Lignin Macromolecule in solution systems Macromolecule in material systems Dispersants Emulsion stab. Resins Polyblends Antioxidant Rubber reinf. Energy

7 Technical lignins Commercial Lignosulfonates (softwood, hardwood) Kraft lignins (softwood, hardwood) Soda lignins (annual plants) Pilot plant scale rganosolv lignins (hardwood, softwood) Steam explosion lignins (annual plants) Acid hydrolysis lignins (softwood)

8 Compounds in spent sulfite liquor (kg/ton of pulp) Component Spruce Birch Lignosulfonate, tot. M w > 5,000 Carbohydrates - Arabinose - Xylose - Mannose - Galactose - Glucose Aldonic acids Acetic acid Extractives Misc. compounds 480 1) ) Ethanol 1) calculated as lignin

9 Lignosulfonate as dispersing agent (Borregaard Lignotech) Aq. lignosulfonate

10 Compounds in kraft black liquor (kg/ton of pulp) Component Pine Birch Lignin Carbohydrate derived - Hydroxy acids - Acetic acid - Formic acid Turpentine Resin and/or fatty acids Misc. products Wageningen 2011

11 Modern kraft pulping A lignin outtake can be accepted Pulpwood Fibre processing Pulp & paper The LignoBoost process Black liquor Recovery boiler Lignin Conversion Conversion Chemicals Biofuels Wageningen 2011

12 Precipitated kraft lignin Carbon: 61-65% Hydrogen: 5-7% xygen: 28-30% Sulfur: 1-3% Ash: % Carbohydrates: 1-2%

13 Bonding energies, kcal/mol H CH H CH

14 van Krevelen diagram showing different biomass and fossil materials D, [H]

15 Phenol from kraft lignin at o C Theoretical: cat: Fe-oxide; Co-oxide; C 8.35 H S 0.08 (CH 3 ) H C 6 H (CH 4 ) (H 2 ) (H 2 S) 560 kg/ton lignin Product Volatiles Water Neutrals Mono- High M w Hydrogen C 5 H 12 <240 o C phenols >240 o C % by weight CH 3 CH 3 CH 3 CH 3 CH 3 CH 3 H 3 C CH 3 Yield, %: Ref: Huibers and Parkhurst Jr, 1983

16 Kraft lignins; Analytical data Functionality Spruce Birch E. globulus Aromatic, mmol/g Aliphatic (total), mmol/g Carboxyl groups, mmol/g Molecular mass, M w Polydispersity, M w /M n Glass transition temp. T g, o C Free aromatic C5, mmol/g n.a.

17 Some lignin reactions 1) Lignosulfonates upgrading 2) Reactive position Lignin CH 3 reactive aldehyde sulfite amine phenol dispersing agents chelating agents adhesives (Softwood) kraft lignin 3) Kraft lignin (low M w -fraction) + polyol + isocyanate polyurethane Wageningen 2011

18 Sulfomethylation of lignin Lignin CH 3 + NaHS 3 + CH 2 ~140 o C Na Na 3 S H C H Lignin CH 3 A maximum of ~2 mmol sulfonate groups/g of lignin can be obtained ~33% reactive positions

19 13 C-NMR of tannin and lignin A R B B A ppm A B D Spruce tannin catechol R resorcinol R D ppm Spruce lignin phloroglucinol C CH 3 C Wageningen 2011 guaiacol ppm

20 Reactivity towards formaldehyde Phloroglucinol: highly reactive Resorcinol: intermediate Catechol/phenol: low Tannins are presently used as wood adhesives, lignins are not In the future, formaldehyde-free adhesives based on lignin might be developed Wageningen 2011

21 Lignin uniform reactivity

22 Polyurethane from oxypropylated kraft lignin H H CH 3 K CH 2 CH 3 CN R NC CH 2 CH 3 NH R HN n

23 Manufacturing process for CF Starting material: Polyacrylonitrile (PAN; ~90% of CF) Petroleum/coal pitch Regenerated cellulose (rayon)

24 Carbon fiber use.towards the automotive industry Driving force: lower price of CF Advantage: lower weight of vehicle, less gas consumption

25 Even a small lignin withdrawal can be interesting 650,000 tonnes of pulp Lignin withdrawal of 10% yields 33,000 tonnes converted to 16,000 tonnes of CF to support 160,000 cars with CF-composite (~40% replacement)

26 dw/d log M dw/d log M SEC of kraft lignins before/after fractionation softwood E. globulus SWL SP5 SR5 EL EP5 ER log M (relative polystyrene) log M (relative polystyrene)

27 Carbon fibre characteristics

28 Conclusions Large quantities of lignins will be formed in future biorefineries Most of the lignin will be used as internal process fuel or subjected to gasification (C + H 2 ) A partial out-take of (purified) lignin is technically feasible in different types of processes Carbon fibre would be an interesting option but will require new knowledge about the structure-property relationship ther uses: biofuels, adhesives and other polymers (esters, ethers, urethanes), BTX chemicals, activated carbon There is still a long way to go