CATALYTIC UPSTREAM BIOREFINING OF LIGNOCELLUL OSES TO LIGNIN OILS AND HYDROLYSABLE HOLOCELLULOSES Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften Vorgelegt der Fakultät für Chemie und Biochemie der Ruhr-Universität Bochum Von Paola Ferrini aus Corbetta, Italy Bochum 2016 II Die vorliegende Arbeit wurde in der Zeit von November 2011 bis Februar 2016 am Max- Planck-Institut für Kohlenforschung in Mülheim an der Ruhr unter der Leitung von Herrn Dr. Roberto Rinaldi angefertigt. Referent: Dr. Roberto Rinaldi Korreferent: Prof. Dr. Martin Muhler III IV Ai miei genitori e a mio fratello, che mi hanno supportata e incoraggiata durante questo periodo Science is not only a disciple of reason but, also, one of romance and passion. (Stephen Hawking) V VI ACKNOWLEDGEMENTS First of all, I would like to thank my supervisor Dr. Roberto Rinaldi, for the great opportunity to work on this interesting topic, for the continuous support and encouragement during these years, and the numerous chances he gave me to expand not only my scientific knowledge but also my personal experience. Thank you! I would like to thank Prof. Dr. Martin Muhler for agreeing to be the second referee. I would also like to thank Prof. Dr. Ferdi Schüth, for the support and the advices during these years, and for the great and productive working environment of this group. In addition, I would like to thank Prof. James Dumesic, for welcoming me in his group during my visiting period, giving me the opportunity to develop a new project and exploit my potential also outside my working group. Moreover, I would like to thank, in no particular order: Xingyu, for guiding me in the first steps of my PhD, for the trainings and for the fruitful discussions; Jan, for the precious scientific support, the encouragement during my PhD, and his invaluable friendship; Claudio, for the help with the work, for the countless conversations (scientific and not) and for putting up with me even in my worst moments; Heitor, for the training of the HPLC/GPC (later become my best friend and worst enemy), and because from the first moment he took me under his wing like a sister; VII Marco and Matthew, among other things, for proofreading this thesis and many other manuscripts, and for all the “English questions” they had to answer; Michael, Zhengwen, Gaetano, Jorge, Hebert, Ilton, Nadine, Alex, Niklas, Marcelo, Sayantani, Mats, Jakob, JiNa, who all contributed to making the Rinaldi’s group such a productive working environment; Udo, for his precious help in the lab during these years; The Feinmechanik, especially Knut and Dirk, for the great work (and the patience) in the maintenance of the reactors; Mr. Deege, Heike and Marie Sophie (HPLC), Bodo, Christophe and Wolfgang (NMR), Claudia and Jan (XRD), for the measurements and the help in the discussion of the analyses; Prof. Camila Alves de Rezende, for the collaboration and the SEM pictures of the pulps; Wolfgang and Harun, for the help and the fruitful discussions; Sarah, because she was always by my side; these years at the institute wouldn’t be the same without you! Valeria, Stefano, Luca and Gabri, for their friendship and for bringing a bit of Italy in Mülheim; Annette and Kirsten, for their support and their useful advices; Tobi Z, Daniel W, Johannes, Marc, Rene, Morten, Daniel J, Nico, Teo, Gonzalo, Hannah, Tobi G, Daniel K, Romain, Valentina, Jorro, Julia, Xiaohui, Ryan, Jacob, Kameh, Kiki, Wojciech, Felix, Mano, JP, Caro N, Mario, Caro G, Maria, Christian, and all the members of VIII AK Schüth which contributed to building an amazing working group and left me an unforgettable memory of this period; Dumesic’s group, especially Tom, Max, Zach, Ali, Ana and Mrunmayi (M), for all their help during my staying in Madison; All my friends, who, either from nearby, or from far away, were always next me in these years; Finally, I deeply thank and dedicate my thesis to my parents and my brother: your support, love and encouragement were my drive in this period. Grazie! IX X Contents CONTENTS Acknowledgements ............................................................................................................................ VII List of abbreviations ........................................................................................................................ XVII 1. Introduction ..................................................................................................................................... 1 2. State of the Art ................................................................................................................................ 5 2.1 Lignin structure ..................................................................................................................... 6 2.2 Biomass pretreatment and fractionation .................................................................. 10 2.2.1 Physical pretreatments ........................................................................................... 15 2.2.2 Physicochemical pretreatments .......................................................................... 16 2.2.3 Chemical pretreatments ......................................................................................... 17 2.2.4 Biological pretreatments ........................................................................................ 18 2.3 Lignin depolymerization ................................................................................................. 19 2.4 H-transfer .............................................................................................................................. 24 2.5 Outlook ................................................................................................................................... 25 3. Organosolv and Catalytic Upstream Biorefining Processes – Lignin Fraction .... 27 3.1 Introduction ......................................................................................................................... 27 3.2 Organosolv process and lignin release study .......................................................... 27 3.3 Catalytic upstream biorefining process ..................................................................... 31 3.4 Effect of temperature on lignin products .................................................................. 33 3.4.1 Hydrogen and oxygen content .............................................................................. 33 3.4.2 Molecular weight distribution .............................................................................. 35 XI Contents 3.4.3 GCxGC ............................................................................................................................. 38 3.4.4 Thermogravimetric analysis ................................................................................. 44 3.4.5 2D HSQC NMR ............................................................................................................. 47 3.4.6 Quantitative 13C NMR ............................................................................................... 50 3.5 Conclusions ........................................................................................................................... 52 4. Organosolv and Catalytic Upstream Biorefining Processes: Pulp Fraction .......... 53 4.1 Introduction ......................................................................................................................... 53 4.2 Pulps characterization ...................................................................................................... 53 4.2.1 Pulp composition ....................................................................................................... 53 4.2.2 Crystallinity .................................................................................................................. 58 4.2.3 Degree of polymerization ....................................................................................... 60 4.2.4 Morphology .................................................................................................................. 63 4.3 Enzymatic hydrolysis ........................................................................................................ 67 4.4 Conclusions ........................................................................................................................... 71 5. Effect of Solvent Composition on Catalytic Upstream Biorefining .......................... 73 5.1 Introduction ......................................................................................................................... 73 5.2 Wood wettability ................................................................................................................ 74 5.3 Pulp fraction ......................................................................................................................... 75 5.4 Lignin oils .............................................................................................................................. 78 5.4.1 Hydrogen and oxygen content .............................................................................. 78 5.4.2 Molecular weight distribution .............................................................................. 79 XII Contents 5.4.3 GCxGC ............................................................................................................................. 80 5.5 Conclusions ..........................................................................................................................