Abstract
The catalyzed conversion of lignocellulose to hydrocarbon energy carriers requires a cascade of reactions that deconstructs and reduces the polymeric, highly oxofunctionalized materials. While lignin is the most intractable component of lignocellulose, its conversion to useful products is key in this catalytic chemistry, because the carbon in lignin is the most reduced one. The chemistry faces steep challenges, as it has to be performed in an aqueous environment under conditions that are highly corrosive towards catalysts. The lecture will outline the successful strategies to produce phenol monomers and oligomers from lignocellulose and the conversion of these intermediate products to high-quality energy carriers. While the depolymerization is controlled by acid-base catalyzed hydrolysis, the key elementary steps involved in the hydrogenation and hydrodeoxygenation of the intermediate products need metal and acid-base catalytic functions, i.e., the cleavage of individual C-O bonds and the addition of hydrogen, which require both functions in concerted and bifunctional manner. The relative importance of the pathways depends subtly on the strength of the C-O bond, the nature of the metal, and the geometric/steric arrangement of the two functions. The nature of the elementary steps differs drastically from those observed catalyzed on solid surfaces because of the presence of water. Water competes on the one side for the active sites, but also stabilizes sorbed and transitions states, and facilitates in particular the desorption of products allowing so to conduct the reactions under very mild reaction conditions. By tailoring the pore radius of the catalysts acid catalyzed carbon-carbon bond formation is used to synthesize tailored energy carriers. The importance of basic research for to solve the practical problem will be highlighted throughout the lecture and the potential and limitations of the approach will be critically discussed.
Biography
Johannes A. Lercher studied Chemistry at the TU Wien where he received his doctorate (Dr. techn.) under the supervision of Prof. Heinrich Noller in 1981. After a visiting lectureship at Yale University, he joined TU Wien as lecturer and Assoc. Professor. In 1993 he was appointed Professor in the Department of Chemical Technology at the University Twente, the Netherlands and moved in 1998 to his current position as Professor of Chemical Technology at the TU München, Germany. Since 2012 he is also Director of the Institute for Integrated Catalysis at the Pacific Northwest National Laboratory. He is external member of the Austrian Academy of Sciences and Member of the Academia Europaea as well as Honorary Professor of the China University of Petroleum and the Qingdao Institute of Bioenergy and Bioprocess Technology of the Chinese Academy of Sciences. Being the current Burwell Lecturer of the North American Catalysis Society, he has served as President of the International Zeolite Association and is currently the Vice President of the German Catalysis Society. He is currently Editor-in-Chief of the Journal of Catalysis. His research activities in the field of Heterogeneous Catalysis have generated over 410 publications, several patents and a large number of invited plenary lectures. His research is focussed on fundamental aspects of oxide and molecular sieve based sorption and catalysis, new routes to activate and functionalize hydrocarbons, deconstruction and defunctionalization of lignocellulose, design of complex multifunctional catalysts, and the in situ characterization of catalytic processes.