Lecture: Carbon dioxide and biomass molecules provide a green pathway to chemicals and materials – Interaction of catalysis, kinetics and transport phenomena

ABSTRACT OF THE LECTURE

Utilization of carbon dioxide as a reagent for chemical processes is a very fashionable research area nowadays, but in fact, pioneering effort on this subject on Finnish soil was initiated about 20 years ago at University of Oulu and Åbo Akademi, in collaboration with Université de Bourgogne. One of the topics of the research was synthesis of dimethyl carbonate. Since those days, the research on CO2 chemistry has grown explosively, covering topics such as methanol and methane synthesis using CO2 and hydrogen as reagents. Northern European forests are rich sources of biomass; for example, Finland and Sweden have the highest amount of woody biomass per capita. The side streams from pulping process contains very functional molecules, such as terpenes and fatty acids, which can be valorized with the aid of CO2 in the presence of homogeneous, heterogeneous and enzymatic catalysis. The exciting pathway of fatty acid esters and terpenes via epoxides to carbonates is discussed in the lecture.

The entire process can be sketched as follows: Unsaturated fatty acid /Terpene → Epoxide → Carbonate → Polymers. The reaction route is based on the reactivities of the double bonds in unsaturated fatty acids and terpenes with hydrogen peroxide to epoxides which react further forming carbonates. Hydrogen peroxide, the environmentally friendly oxidant, can be obtained via direct synthesis from molecular hydrogen and oxygen, which in future will be available in large amounts thanks to the development of improved electrolysis technology.

Fatty acid methyl esters and terpenes have been used substrates at Åbo Akademi and extensive kinetic and mass transfer experiments have been conducted in a pressurized autoclave operating under isothermal conditions. Kinetic models based on plausible molecular mechanisms for the carbonation processes are presented and the modelling results are discussed from the viewpoints of reaction mechanisms and reactor technology.

Implementation of this novel technology requires intensive cross-disciplinary collaboration between chemists, physicists and chemical engineers. Deep-going chemical thinking and phantasy-rich experimentation is needed to find suitable catalysts and to propose mechanistic hypotheses, which are the basis of rational development of rate equations in kinetic models. Homogeneous catalysts are known for their high activity and selectivity, but for large-scale production, solid heterogeneous catalysts are preferable, because catalyst separation is much easier both in batch and continuous processes. For carbonation reactions, a big effort is focused on heterogenization of homogeneous catalysts by grafting, as illustrated in the figure below. Results of advanced mathematical modelling will be presented in the lecture, following the principles ‘from reaction mechanism to reactor design’ and ‘from green chemistry to green process technology’.

THE LECTURER

Professor Tapio Salmi, Doctor Honoris Causa at the University of Oulu and Tallinn Technical University, is a researcher in the field of chemical reaction engineering. He works as a Professor of Chemical Reaction Technology at Åbo Akademi University.

During the years 2009-2013 and 2019-2023 he has served as an Academy Professor appointed by the Research Council of Finland, i.e., the former Academy of Finland.

Professor Salmi’s research focuses especially on chemical engineering phenomena, reaction kinetics and catalysis as well as on intensification of chemical processes, reactor design, and innovative biomass refining. He has supervised more than 70 doctoral theses and he is an author and co-author of around 700 scientific peer-review articles, four textbooks and several patents.

Professor Salmi has done an impressive career in catalysis and reaction engineering research and has actively collaborated with researchers at the University of Oulu having, thus, an enormous and long-lasting impact on our researcher education in chemical engineering, including reactor engineering and catalysis.

You are warmly welcome to listen the lecture and discuss about the timely topic area!


Additional information

Prof. Riitta Keiski
Environmental and Chemical Engineering research unit
riitta.keiski@oulu.fi
+358 40 726 3018

Docent Satu Pitkäaho
Environmental and Chemical Engineering research unit
satu.pitkaaho@oulu.fi
+358 29 448 2374

Dean, Prof. Antti Niemi
Faculty of Technology
antti.niemi@oulu.fi
+358 29 448 2071