CATALYSTS FOR SELECTIVE CONVERSION OF PLANT CELL WALL POLYSACCHARIDES

Transcription

1 CATALYSTS FOR SELECTIVE CONVERSION OF PLANT CELL WALL POLYSACCHARIDES Nathan S. Mosier Associate Professor, Ag. and Bio. Engineering Purdue University 2014 Frontiers in Biorefining St. Simons Island, Georgia USA

2 ACKNOWLEDGEMENTS Collaborators M.R. Ladisch, Y. Kim (U WI-River Falls), A.S. Engelberth, E. Ximenes LORRE M. Abu-Omar, N. Carpita, M. McCann, J. Bozell, B. Dononhoe, P. Ciesielski et al. C3Bio Students Mosier Group Barron Hewetson, Ximing Zhang, Amanda Kreger, Yulin Lu, Maarten Kootstra Abu-Omar Group Ian Klein, Yuan Jiang, Eurick Kim Funding 2 This work was partially supported by the US Department of Energy, Office of Basic Energy Sciences as part of an Energy Frontier Research Center. This work was partially supported by the Purdue University Agricultural Research Programs through Hatch Project IND010677H.

3 3 FRACTIONATION OF PETROLEUM Diesel Other Distillates Reported in Gallons Jet Fuel Other Products Heavy Fuel Oil Liquefied Petroleum Gasoline Source: Energy Information Administration, 2010

4 4 FRACTIONATION OF BIOMASS Diesel Other Distillates Jet Fuel Other Products Heavy Fuel Oil Liquefied Petroleum Gasoline Source: Energy Information Administration, 2010

5 5 BIOMASS CONVERSION PROCESSES Fractionation Gasification Pyrolysis Condensed Phase Catalytic Upgrading Thermochemical Biochemical Alkanes Aromatics Polyols Organic Acids Alcohols 180 Fractionation Pretreatment Enzym. Sacch. Fermentation Biocatalytic Upgrading 50 C

6 6 PRETREATMENT AS FRACTIONATION Lignin Cellulose Pretreatment Hemicellulose Mosier et al., Bioresource Technology 96(6): (2005).

7 7 LIGNIN FIRST Solvent Phase Polar Solvent Non-Polar Solvent Lignin-derived compounds Hemicellulose extracts Solid Phase Cellulose (more reactive)

8 8 CARBOHYDRATES FIRST Solvent Phase Ionic Liquids Aqueous Solvents Catalyst Selection to Improve Fractionation Effectiveness Selectivity Hemicellulose-Derived Compounds Some lignin (?) Solid Phase Cellulose (more reactive) Lignin

9 9 CATALYST APPROACHES Brønsted Acids Vs. Enzymes Pros Cons Relatively low catalyst cost Rapid hydrolysis rates Cost of neutralization or acid recycle Environmental problems associated with salt disposal Substantial sugar degradation products Pros Cons High specificity/selectivity No degradation products Mild hydrolysis conditions High specificity High cost for enzyme production Difficulties in recovery of the enzymes

10 10 DICARBOXYLICACIDS Maleic Acid pka= 1.90, 6.07 Solubility (20 C) = 4.1 M Fumaric Acid pka= 3.03, 4.44 Solubility (20 C) = 0.5 mm Oxalic Acid pka= 1.25, 4.14 Solubility (20 C) = 26 mm

11 MALEIC ACID CLEAN FRACTIONATION % Recovered in Aqueous Phase mM Maleic Acid 160 C 20 Min Corn Stover Switchgrass Poplar Kim et al. Energy & Fuels 26(2): (2012). Xylose Glucose

12 12 IMPROVED SACCHARIFICATION CLSM SEM TEM Image Analysis and Quantification Untreated 20 µm 1 µm 1 µm maleic acid fah 1-2 C4H F5H maleic acid Ciesielski et al., Green Chemistry 2014

13 KINETICS OF FRACTIONATION Biomass Catalyzed by H + k 1 k 2 k 4 Xylose Furfural Humins k 3

14 XYLOSE DEGRADATION Xylose k deg

15 HYDROCHLORIC ACID KINETIC ANALYSIS k ln (X/X0) y = x R² = y = x R² = k deg, min y = 0.473x R² = mM 50 mm 100 mm Reaction time, minutes y = x R² = [H+], mole Lu and Mosier, Biotech Bioeng, 2008

16 ACETIC ACID KINETIC ANALYSIS k ln (X/X0) y = x R² = k deg, min y = x R² = y = x R² = mM 50 mm y = x R² = mm Reaction time, minutes [Acetic acid], mole Lu and Mosier, Biotech Bioeng, 2008

17 MALEIC ACID KINETIC ANALYSIS y = x R² = k ln (X/X0) y = x R² = k deg, min y = x R² = y = x R² = mM 50 mm 100 mm Reaction time, minutes [Maleic acid], mole Lu and Mosier, Biotech Bioeng, 2008

18 XYLANHYDROLYSIS YIELDS Kim, Kreke, Ladisch, AIChE J., 2013

19 XYLANHYDROLYSIS YIELDS Kim, Kreke, Ladisch, AIChE J., 2013

20 RELATIONSHIP BETWEEN [H+] AND K3 20 Kim, Kreke, Ladisch, AIChE J., 2013

21 MALEIC ACID CAN FAVOR DEHYDRATION

22 MALEIC ACID CAN FAVOR DEHYDRATION Xylose Conversion (%) Furfural Yield (%) Hydrolysis: 160 C, 20 Min Dehydration: 200 C, 15 Min

23 23 CONCLUSIONS Low-temperature ( C) + high acid loading = increased xylose yield Dicarboxylic acids (maleic and oxalic) outperform sulfuric acid by preventing xylose degradation to humins Xylose degradation rate by dicarboxylic acids is inversely dependent on ph Mineral acids requires a lower ph than dicarboxylic acids to achieve equivalent xylose yields.

24 QUESTIONS 24