1. Production of Platform Chemicalsin the DIBANET Project UsingNovel Pre-treatment Methods and Acid HydrolysisMichael H.B. Hayes CarboleaChemical and Environmental Sciences University of Limerick

2. The DIBANET Project Development of Integrated Biomass Approaches NETwork Project Title: The Production of Diesel Miscible Biofuels from the Residues and wastes of Europe and LatinAmerica.13 partners, 6 from the EU and 7 from LA 3. DIBANETProcesses, Products, and Linkages (As in the Original proposal) 4. DIBANET partners 4 5. Initial Basic Aims Initially, a major aim was to produce Levulinic acid (LA) from hexose sugars and to esterify with ethanol to produce the diesel-miscible biofuel ethyllevulinate (EL)OH3COHO LAEL 6. Levulinic Acid Levulinic acid (LA), derived fromcarbohydrates is an excellent plaformchemical from which numerous fueladditives can be derived.OH3COHO Equally important it can be the source ofnumerous chemicals and materials nowderived from petrochemicals 7. Carbohydrates Most abundant biogenic building-blocks. General elemental composition of (CH2O)n Oxygenated nature affords superior (tohydrocarbons) chemical properties forconversion and utilisation. Most abundant simple sugars in biomass areglucose, mannose, galactose (6 carbonsugars) and xylose and arabinose (5 carbonsugars). Tend to be linked in polymers(polysaccharides) 8. MAJOR COMPONENTS OFLIGNOCELLULOSIC MATERIALS Cellulose (A polyglucose)45-50% Hemicellulose (Composed of the hexoses glucose, galactose and mannose, and of the pentoses arabinose and xylose) 20-25% Lignin ca 25% Waxes, suberins, etc ca 5% At this stage our interest is focused on thecellulose and hemicellulose components forthe biorefining processes. 9. First and Second GENERATION BIOREFININGFIRST AND SECOND Generation Biorefining The folly of using starch and edible oil food crops togenerate first generation biorefinery fuels is wellrecognised. It can take almost as much energy togenerate these fuels as they provide. There are alsoserious environmental concerns in growing thecrops. In contrast the Second Generation Biorefining oflignocellulose crops and of carbohydrate wastes donot place demands on the environment and canmatch petroleum as sources of the fuels and ofplatform chemicals. 10. STARCH and CELLULOSE There follows depictions of the(poly)glucose molecules starch andcellulose. Cellulose, the major component inbiomass, is the most abundant organicmaterial on earth. Despite the similarity in componentglucose molecules, cellulose andstarch have vastly different properties. 11. Starch and Cellulose The glucose in both molecules is in cyclicform and in what is called the chair conformation. In both cases the OH on Carbon 1 reactswith the OH on Carbon 4 of a neighbouringunit. Water is lost and the C of 1 is linked tothe C of 4 by an O bridge. Branching canoccur in starch when the linkage occursbetween C1 and C6 The differences arise because of theconfiguration of the OH on C1. 12. Starch Note that the OH on C1 is axial (belowthe plane of the ring). The bulky substituents on the other Catoms are equatorial. Note when the C1 to C4 bondingoccurs a loose (random coil) structureresults. Enzymes readily enter the structure,and release the glucose molecules. 13. StarchHOH2COO 4 HO1C6 OOH52HOH2C 6O 1 HOH2CO branching poin OH O 4 O5 2O 4HO 1 13 OH H2C 6 HOO OHHOH2C O 4 O 1O 4 HO OHHOH2C HOO OH O 4 HO(a) AmyloseOH(b) Amylopectin 14. Cellulose The OH on C1 of cellulose is equatorial. It bonds through the O-bridge to the C4 of aneighbouring molecule. This gives a linear,or linear helical molecule. Hydrogen bondingtakes place between the strands , and accessof cellulase enzymes is inhibited. Hence it is difficult to release glucose fromcellulose. 15. Cellulose 16. LIGNIN The linkages in lignin are through C toC bonds, or as ether linkages. These are very difficult to break. Hence lignin has a strong resistance tochemical and biological degradationprocesses. They can be good sources of phenolsand other chemicals. 17. LIGNIN 18. Miscanthus x giganteus Bulk density = 1260 kg/m3Length 10 mmDiameter 35 mm Ultimate CompositionXylan 19.60%Arabinan 2.20%Glucan40.70%Galactan 0.70%Mannan 0.30%Klason lignin 22.00%Acid-soluble lignin1.80%Extractives1.80%Ash3.90%Others 7.20% 18 19. Hydrolysis of biomassOH HOOOHO HO Monosac-HOOH OH charidesOHOHXyloseGlucoseO HOHHYDROLYSIS OrganicOHH3Cacids O OLevulinic acid Formic acidLignocellulosic biomassHO CHO CHOFurans O O5-Hydroxymethyl-Furfural furfural 19 20. Acid Hydrolysis in Biorefining Purely chemical process. In the more conventional system High temperature, fast acid hydrolysis ofbiomass with 1-5% mineral acid in tworeactors. Initially we considered the Biofine,two reactor system. The first reactor hydrolyses the sugars andproduces the intermediate HMF from the C6sugars and furfural from the C5 sugars. The HMF goes to the second reactor wherelevulinic acid and formic acid is formed. 21. Hexoses conversionsGlucan GlucoseGalactanGalactoseHMF Levulinic acid (LA) + FormicacidMannanMannose Humins Time to reachYield (%- max. yieldmol) (min)Glucose25.8% 7HMF 2.8% 6Levulinic58.3%60acid21 22. Problems in the Biorefining ofLignocellulose materials Acceptable yields of the expectedproducts could be obtained from cellulose. But yields from biomass have beendisappointing That required a re-evaluation of theprocess. It was found that Lignin is the majorcause of depressed LA yields. 23. The Carbolea BiorefiningApproach Biomass is mixed with inexpensivechemicals. As interactions take placethe pressure reaches 40 bar and thetemperature reaches 160 oC, Upon therelease of pressure and lowering of thetemperature the soluble componentscontaining lignols, lignin, andhemicellulose are solubilised, and thesolid residue containing cellulose isretained. 24. Carbolea Biorefining (Continued) Lignin products are recovered whenthe decantate is diluted with water. There is no degradation of thecellulose, and only minor degradationof hemicellulose. When cellulase enzymes areintroduced a very significant hydrolysisto glucose takes place. This is beingfurther investigated at this time. 25. Carbolea Biorefining (Continued) In addition to enzymatic hydrolysis, theuses of solid acid catalysts and mineralacid hydrolysis and degradations arebeing investigated in a search for moreefficient procedures for the productionof LA, formic acid, and furfural. 26. Pretreatment Technologieshttp://genomics.energy.gov/gallery/biomass/originals/558.jpgRemoval of hemicellulose and/or lignin, e.g.acid, alkaline, oxidative agents 26 27. Carbolea Pre-Treatment Process It has become clear that lignin,especially, and possibly the lesseramounts of suberins, etc., in biomassinhibit LA production. Delignification brought about by use offormic acid and H2O2 can overcome theinhibitions. 28. HCOOH + H2O2 Addition of NaOH + Fe2(SO4)3 to bomassin HCOOH + H2O2 (5% and greater)gives rise to an autothermal process inwhich the lignin and hemicelluloses aredissolved and can be recovered fromthe digestate. The cellulose pulp is essentiallypreserved. 29. Modified Parr Reactor 30. Oxidative Pretreatment 31. Temperature profiles and liquor composition of the pretreatedbiomass; a) 2.5% initial H2O2, b) 5.0% initial H2O2, c) 7.5% initial H2O2. d) Pressure profile of the reactor with various initialperoxide 32. Cellulase Hydrolysis 33. Levulinic Acid (LA) MP 33-35 oC ; BP 245 -248 oC Levulinic acid is a potential precursor tonylon-like polymers, synthetic rubbers, andplastics It is a precursor in the industrial productionof other chemical commodities such asmethyltetrahydrofuran, valerolactone, andethyl levulinate. LA is used in cigarettes to increase nicotinedelivery in smoke and binding of nicotine toneural receptors Previously low yields, highcost ~ 4/kg. 34. LA in Diesel: Ethyl Levulinate (EL) EL: An ester of levulinic acid that isused as an oxygenate diesel additive. Due to their different chemical characteristics,diesel and ethanol do not mix well. EL is prepared by esterifying levulinicacid with fuel grade ethanol. 35. Ethyl Levulinate Formulation EL has an oxygen content of 33% giving a 6.9%oxygen content in the blend. The result is asignificantly cleaner burning diesel fuel. Fuel has high lubricity, and a reduced sulphurcontent. Meets all the ASTM D-975 diesel fuel specifications. No significant losses in km per L Formulation has 20% ethyl levulinate, 1% co-additiveand 79% diesel. Ethyl levulinate has advantages over other dieseloxygenates: Improves the viscosity of conventionalbiodiesels. 36. LA-Derived Transport Fuels 37. Levulinic Acid Derived Fuels:Methyltetrahydrofuran (MTHF) Oxygenated fuel extender for petroleum. Produced via the hydrogenation of LA or fromhydrogenated furfural. Octane Value ~ 87 Km L-1 comparable to gasoline Low Reid Vapour Pressure (3.09 psi versus 9.11 forpetrol) reduces RVP of ethanol/petrol blends. Hydrophobic, LHV = 32 MJ/kg. 20% oxygen content (like MTBE), results in a cleanerburn with less pollutants. Proven in tests up to 100% volume with petrol. Willmix in conventional engines up to 40%. 38. Conversions of LA to alternativefuelsO H2 H 2OOO H3C O+ H2H3C OH H3C Ru/C Pd/Nb2O 5OH OPentanoic acid-ValerolactoneOLevulinic acid Pd/Nb2O5 H3COHH2 PdRe/C HO CH3 + CO2, H2O H H2OH2H2 O O OH O Pt/Nb2O5 OH5-nonanoneH3C H3CDiesel blenderO CH31,4-pentanediol USY zeoliteOH2 H+Ethyl Levulinate H2 OH3CO2-Methyltetra- hydrofuran (MTHF)Gasoline38 39. Furfural and its derivatives Resin Rocket fuelPharmaceutical MedicineSolventCorma et al. (2007) Chem. Rev., 107(6), 2411-2502.39 40. Levulinic Acid as a Platform Chemical OHerbicide O OHO ORH3C NH2 OO 5 -n o n a n o n e - a m in oOHA lk y l le v u lin a tele v u lin ic a c id O R H3COHOP e n ta n o ic a c id OPolymer OHOHOOHH3CH3COCH3 O R -v a le ro la c to n e D ip h e n o lic a c idLevulinic acidOHOOH OH H3CHOH3CO O1,4-pentanediol2 -m e th y l S u c c in ic a c idte tra h d y ro fu ra n 41. Maximizing the Values of Biorefinery Operations It is important to be able to recover and toutilise all of the useful products generated inBiorefining Operations because All of the materials formed in Biorefiningprocesses have value. Biorefining involves hydrolysis andthermal processes, as outlined again inthe presentation that follows. 42. DIBANETProcesses, Products, and Linkages 43. Pyrolysis of Biomass Intermediate pyrolysis processes for theresiduals gives bio-oil (which we esterify togive a product with a HHV of ca 30 MJ kg-1). The syngas evolved can be used to supplythe energy needs. The biochar formed can be an excellent soilamender, sequesterer of C, and an excellentpromoter of plant growth. This interest arosefrom observations of Amazonian Terra Pretas 44. Biochar Amendments at UL We at UL are extensively investigatingthe processes and mechanisms ofbiochar formation. There follows pictures of maize grown inpot experiments 28 days after planting insoil amended with biochar fromMiscanthus x giganteus The soil in the pot on the RHS was notamended. The other pots were. 45. A bio-char amendment trialexperiment 46. Studies on Biochar Our extensive studies on biochar showthat porosity and surface area areimportant, as is the temperature andtime of heating. We have noted the extensiveproliferation of microorganisms aroundroots that accumulate around thebiochar enrichments 47. Characterisations of Biochars We routinely measure surface area, doscanning electron microscopy (SEM),measure high heating value (HHV), andinvestigate composition and aspects ofstructure using Raman and solid state13 C nuclear magnetic resonance (NMR)spectroscopies. There follows NMRspectra of miscanthus, and of biocharpyrolysed at different temperatures. 48. CPMAS 13C NMR of Miscanthus 49. Miscanthus Biochars (1 Bar) 50. ACKNOWLEDGEMENTS Karla Dussan Dr. Buana Girisuta Dr. Donncha Haverty Dr. Daniel J.M. Hayes Dr. James Burdon Dr. Anna Piterina Fergus Melligan 51. Compounds from Pressurised Pyrolysis of Lignin (1) 52. Compounds from Pressurised Pyrolysis of Lignin (2) 53. Compounds from Pressurised Pyrolysis of Lignin (3)