Liquid-phase dehydration of lactic acid for the production of bio-acrylic acid Development of a multi-step process Flüssigphasen-Dehydratisierung von Milchsäure zur Produktion von biobasierter Acrylsäure Entwicklung eines mehrstufigen Prozesses Der Technischen Fakultät der Friedrich-Alexander-Universität Erlangen-Nürnberg zur Erlangung des Grades DOKTOR-INGENIEUR vorgelegt von Matthias Kehrer, M. Sc. aus Nürnberg Als Dissertation genehmigt von der Technischen Fakultät der Friedrich-Alexander-Universität Erlangen-Nürnberg. Tag der mündlichen Prüfung: 17. Dezember 2018 Vorsitzende/r des Promotionsorgans: Prof. Dr.-Ing. Reinhard Lerch Gutachter/in: Prof. Dr. Peter Wasserscheid Prof. Dr. Nicolas Vogel To my family “Obstacles don’t have to stop you. If you run into a wall, don’t turn around and give up. Figure out how to climb it, go through it, or walk around it.” Michael Jordan Preface i Preface The present work was carried out in the period from May 2014 to December 2017 at the Institute of Chemical Reaction Engineering of the Friedrich-Alexander-University Er- langen-Nürnberg, headed by Prof. Dr. Peter Wasserscheid. The results presented herein where achieved within the scope of the research project “Liquid-phase dehydration of lactic acid obtained via fermentation for the production of bio-acrylic acid”, which was carried out in close collaboration with the industrial partner Procter & Gamble. At this point, I would like to dedicate personal thanks to a large number of people and their various contributions, involved in the development of this work: First and foremost, I would like to thank my supervisor, Prof. Dr. Peter Wasserscheid, for giving me the opportunity to be part of this interesting and exciting project and for the excellent mentoring during the entire period of this thesis. Dear Peter, I really appreciate your challenges, your advice and your trust in my work –as a result I have developed myself on a personal and professional level. Moreover, I would like express my thanks to Prof. Dr. Nicolas Vogel for kindly accept- ing the second review of this thesis and also to the other members of the PhD com- mittee. I am very thankful to my research group head, Dr. Jakob Albert, for the valuable sup- port, exciting discussions and the useful tips from the engineering perspective. In particular, I would like to thank the whole project team, namely Jens, Julian and Nicola for the energetic working atmosphere and the unlimited team spirit. Working with you was great and I enjoyed it tremendously! I am also very grateful for the excellent scientific and financial support from our in- dustrial collaboration partner P&G. Special thanks goes to Dr. Peter Dziezok and Dr. Dimitris Collias for their inexorable interest and support, the fruitful discussions and the interesting insights into the work environment of P&G. In addition, financial sup- ii port by the Bundesministerium für Ernährung und Landwirtschaft through the Facha- gentur Nachwachsende Rohstoffe e.V. (FNR, Project No 22009614) is gratefully acknowl- edged. I would further like to thank all students I had the privilege to get to know or even supervise during my time at the CRT. I especially thank Vera, Katrin, Julian and Simon for their support and the pleasant and friendly collaborations. I wish you all the best of luck in your future endeavors and scientific career. Moreover, I would also like to extend my sincere thanks to all the people who have done the important and indispensable work in the background: Dear Mrs. Menuet, Mrs. Singer and Mrs. Bittan, thank you for your support concerning all administrative tasks and for the entertaining conversations. Dear Michel, Achim, Julian, Sascha and Alex, thank you for your help concerning technical and especially electrical tasks and the related and funny “sideshow”. Furthermore, I like to dedicate a special mention to the motivating, professional and personal atmosphere in the CRT group and especially in the “Green Couch Office”. It was a great time and I will miss all the diverse activities and the nice and helpful colleagues I met here over the past few years. The most important part of my acknowledgement is addressed to my whole family. Thank you for your unlimited support and the spirit of unity! My greatest “Thank you” goes to my beloved wife Varina for her motivation, her patience and her love, which is beyond comparison! You are the best thing that ever happened to me! Last but not least, I like to thank all others whose names are not mentioned here but who (in)directly contributed to the success of this PhD thesis. I really enjoyed the last 3.5 years at the CRT. All the (work) experiences I gained, the “friends for life” I made and the daily adventures are something I will remember and benefit from for the rest of my life! Publications, contributions and supervised projects iii Publications, contributions and supervised projects Parts of this work have been previously published or presented. Publications in scientific journals M. Kehrer, J. Mehler, N. Taccardi, J. Nagengast, J. Kadar, D. Collias, P. Dziezok, P. Wasserscheid and J. Albert, ChemSusChem, 2018, 11 (6), 1063-1072 J. Nagengast, S. Hahn, N. Taccardi, M. Kehrer, J. Kadar, D. Collias, P. Dziezok, P. Wasserscheid, J. Albert, ChemSusChem, 2018, Accepted Author Manuscript. doi:10.1002/cssc.201800914 Conference contributions M. Kehrer, J. Albert, P. Wasserscheid, D. Collias, oral presentation with the title “Novel liquid-phase technology for the production of bio-acrylic acid”, 2017, Jahrestreffen Deutscher Katalytiker, Weimar, Germany M. Kehrer, J. Albert, P. Wasserscheid, D. Collias, poster presentation with the title „Liquid-phase dehydration of lactic acid towards bio-acrylic acid“, 2017, International Symposium on Green Chemistry (ISGC), La Rochelle, France Patents J. Albert, P. Wasserscheid, N. Taccardi, J. Nagengast, M. Kehrer, J. Kadar, D. I. Collias, Patent WO 2018022828, 2018 J. Albert, P. Wasserscheid, N. Taccardi, J. Nagengast, M. Kehrer, J. Kadar, D. I. Collias, Patent WO 2018022826, 2018 iv J. Albert, P. Wasserscheid, N. Taccardi, J. Nagengast, M. Kehrer, J. Kadar, D. I. Collias, 14739P, US, 2017, Patent pending. Student Theses Within the frame of the research work at the Friedrich-Alexander-University Erlan- gen-Nürnberg, the below listed student projects have been technically and theoreti- cally supervised by the author of this dissertation. The following student theses are not necessarily published and may only be available from the university’s library (FAU Erlangen-Nürnberg). Included raw data sets from supervised student work or references to the latter are marked with the respective number of the following direc- tory. [A] K. Huber, “Catalytic esterification of fermentatively-derived lactic acid to var- ious alpha-acyloxy derivatives”, bachelor thesis, 2015 [B] V. Haagen, “Alpha-acyloxy derivatives of fermentatively-derived lactic acid: Synthesis, characterization and suitability as intermediate towards bio-acrylic acid”, bachelor thesis, 2015 [C] J. Mehler, “Synthesis of 2-bromopropionic acid from fermentatively-derived lactic acid and its derivatives”, master thesis, 2017 Abstract v Abstract This thesis deals with the development of a novel liquid-phase dehydration process of lactic acid (LA) for the production of bio-acrylic acid (AA). The approach of dehy- drating LA in the liquid phase is expected to offer advantages over so far existing gas-phase dehydration processes and may therefore provide a technical as well eco- nomically feasible and sustainable alternative to the incumbent petro-based route. The first part of this work provides a general introduction of the developed “NADA” technology, enabling the production of AA in a liquid phase process. The one-step and HBr-triggered dehydration of LA was realized in acidic bromide ionic liquids. Subsequently, current limitations of the process using LA as substrate were ad- dressed and a multi-step processing of the technology was conceptualized, based on the postulated reaction mechanism of the liquid-phase dehydration system. In the main part of this work, a multi-step liquid-phase dehydration process for the production of bio-AA from LA, proceeding via brominated LA-species, was devel- oped. The feasibility of splitting the “NADA” process into a spatially separated reac- tion sequence of the postulated mechanism was proven. Three individual reactions, namely bromination of LA, isomerization of 2- to 3-bromopropionic acid and dehy- drobromination of 3-bromopropionic acid to AA were developed and largely opti- mized, respectively. In this context, bromide ionic liquids played a crucial role as re- action medium and/or reactant. After evaluation of the multi-step approach from LA towards bio-AA via brominated LA-species, possibilities for potential process shortcuts were finally addressed. The presented results in this thesis contribute to the understanding of AA production from LA via brominated LA-species using (acidic) bromide ILs. The developed “NADA” technology is a novel, selective and sustainable way for the production of AA from LA, contributing to a future economic production of bio-AA. vi Kurzzusammenfassung Diese Arbeit befasst sich mit der Flüssigphasen-Dehydratisierung von Milchsäure (LA) zur Produktion von biobasierter Acrylsäure (AA). Ein solcher und neuartiger Ansatz der Flüssigphasen-Reaktion bietet Vorteile gegenüber bestehender Gaspha- sen-Dehydratisierungsprozesse und kann damit als eine sowohl technisch wie auch ökonomisch attraktive und nachhaltige Alternative