4th International Conference on Technologies & Business Models for Circular Economy Conference Proceedings Editors Sanja Potrč Miloš Bogataj Zdravko Kravanja Zorka Novak Pintarič May 2022 Title 4th International Conference on Naslov Technologies & Business Models for Circular Economy Subtitle Podnaslov Conference Proceedings Editors Sanja Potrč Uredniki (University of Maribor, Faculty of Chemistry and Chemical Engineering) Miloš Bogataj (University of Maribor, Faculty of Chemistry and Chemical Engineering) Zdravko Kravanja (University of Maribor, Faculty of Chemistry and Chemical Engineering) Zorka Novak Pintarič (University of Maribor, Faculty of Chemistry and Chemical Engineering) Technical editor Jan Perša Tehnični urednik (University of Maribor, University Press) Cover designer Jan Perša Oblikovanje ovitka (University of Maribor, University Press) Graphic material Grafične priloge Authors of proceedings & editors Conference TBMCE, International Conference on Technologies & Business Models Konferenca for Circular Economy Date and location Datum in kraj September 13th to September 15th 2021, Portorož, Slovenia Organizing Zdravko Kravanja (University of Maribor, Slovenia), Miloš Bogataj Committee (University of Maribor, Slovenia), Zorka Novak Pintarič (University of Organizacijski Maribor, Slovenia), Dragica Marinič (Chamber of Commerce and Industry odbor of Štajerska, Slovenia), Andreja Nemet (University of Maribor, Slovenia), Mojca Slemnik (University of Maribor, Slovenia), Mojca Škerget (University of Maribor, Slovenia), Katja Kocuvan (University of Maribor, Slovenia), Samo Simonič (University of Maribor, Slovenia), Klavdija Zirngast (University of Maribor, Slovenia), Sanja Potrč (University of Maribor, Slovenia), Sabina Premrov (University of Maribor, Slovenia) & Sonja Roj (University of Maribor, Slovenia). International Zdravko Kravanja (University of Maribor, Slovenia), Zorka Novak Scientific Pintarič (University of Maribor, Slovenia), Miloš Bogataj (University of Committee Maribor, Slovenia), Mojca Škerget (University of Maribor, Slovenia), Mednarodni Mariano Martin (University of Salamanca, Spain), Jiří Klemeš (Brno znanstveni University of Technology, Czech Republic), Agustin Valera-Medina odbor (Cardiff University. United Kingdom), Petar Uskoković (University of Beograd, Serbia), Elvis Ahmetović (University of Tuzla, Bosnia and Herzegovina), Stefan Willför (Åbo Akademi University, Finland), Adeniyi Isafiade (University of Cape Town, South Africa), Hon Loong Lam (University of Nottingham, Malaysia), Mario Eden (Auburn University, United States of America), Timothy G. Walmsley, (Waikato University, New Zeeland), Tomaž Katrašnik (University of Ljubljana, Slovenia), Blaž Likozar (National Institute of Chemistry, Slovenia), Primož Oven (University of Ljubljana, Slovenia), Dragica Marinič (Chamber of Commerce and Industry of Štajerska, Slovenia) & Vilma Ducman (Slovenian national building and civil engineering institute, Slovenia). Published by University of Maribor Založnik University Press Slomškov trg 15, 2000 Maribor, Slovenija https://press.um.si, zalozba@um.si Issued by University of Maribor Izdajatelj Faculty of Chemistry and Chemical Engineering Smetanova ulica 17, 2000 Maribor, Slovenija https://www.fkkt.um.si/, fkkt@um.si Publication type Vrsta publikacije E-book Edition Izdaja 1st Available at Dostopno na http://press.um.si/index.php/ump/catalog/book/678 Published at Izdano Maribor, May 2022 This investment is co-financed by the Republic of Slovenia and the European Union Fund for Regional Development” © University of Maribor, University Press / Univerza v Mariboru, Univerzitetna založba Text / besedilo © Authors & Potrč, Bogataj, Kravanja, Novak Pintarič, 2022 This book is published under a Creative Commons 4.0 International licence (CC BY-NC-ND 4.0). This license al ows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator. Any third-party material in this book is published under the book’s Creative Commons licence unless indicated otherwise in the credit line to the material. If you would like to reuse any third-party material not covered by the book’s Creative Commons licence, you wil need to obtain permission directly from the copyright holder. https://creativecommons.org/licenses/by-nc-nd/4.0/ CIP - Kataložni zapis o publikaciji Univerzitetna knjižnica Maribor 330:502.131.1(082)(0.034.2) INTERNATIONAL Conference on Technologies & Business Models for Circular Economy (4 ; 2022 ; Portorož) 4th International Conference on Technologies & Business Models for Circular Economy, [September 13th to September 15th 2021, Portorož, Slovenia] [Elektronski vir] : conference proceedings / editors Sanja Potrč ... [et al.]. - E-zbornik. - Maribor : University of Maribor, University Press, 2022 Način dostopa (URL): https://press.um.si/index.php/ump/catalog/book/678 ISBN 978-961-286-599-3 (pdf) doi: 10.18690/um.fkkt.3.2022 COBISS.SI-ID 109403907 ISBN 978-961-286-599-3 (pdf) DOI https://doi.org/10.18690/um.fkkt.3.2022 Price Cena Free copie For publishe r prof. dr. Zdravko Kačič, Odgovorna oseba založnika Rector of University of Maribor Attribution Potrč, S., Bogataj, M., Kravanja, Z., Novak Pintarič, Z., Citiranje (eds.). (2022). 4th International Conference on Technologies & Business Models for Circular Economy Maribor: University Press. doi: 10.18690/um.fkkt.3.2022 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY : CONFERENCE PROCEEDINGS S. Potrč, M. Bogataj, Z. Kravanja, Z. Novak Pintarič (eds.) Table of Contents A Novel Process to Produce Adipic Acid by Catalytic Dehydroxylation of Biomass-derived Mucic Acid 1 Florian M. Harth, Brigita Hočevar, Blaž Likozar, Miha Grilc One-pot Algae Conversion Into Sustainable Biofuel by Catalytic Hydroprocessing 11 Dana Marinič, Brigita Hočevar, Miha Grilc, Blaž Likozar Development of FT–IR, UV and Fluorescence Based Analytical Methodology for Lignin Characterisation Rok Pogorevc, Tina Ročnik, Blaž Likozar, Edita Jasiukaitytė-Grojzdek, 19 Miha Grilc A NOVEL PROCESS TO PRODUCE ADIPIC ACID BY CATALYTIC DEHYDROXYLATION OF BIOMASS- DERIVED MUCIC ACID FLORIAN M. HARTH, BRIGITA HOČEVAR, BLAŽ LIKOZAR, MIHA GRILC National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering, Ljubljana, Slovenia florian.harth@ki.si, brigita.hocevar@ki.si, blaz.likozar@ki.si, miha.grilc@ki.si Abstract The heterogeneously catalyzed dehydroxylation of mucic acid to produce adipic acid, a highly relevant polymer precursor, was investigated. The use of methanol as solvent is particularly important since it not only acts as reducing agent but also protects the carboxylic acid functionality by esterification. Re/C was found a wel -suited catalyst for this reaction and not only showed high activity but was also reusable with suitable reactivation procedure. Under optimized reaction conditions, 98 % of dehydroxylated products could be obtained from mucic acid. Moreover, Keywords: combining Re/C with a suitable hydrogenation catalyst (e.g. Pd/C) adipic acid, and performing the reaction under H2 atmosphere steers the biomass, reaction towards adipic acid ester. Therefore, it could be shown dehydroxylation, heterogeneous that adipic acid derivatives are available from biomass-accessible catalysis, mucic by this novel and renewable approach. rhenium DOI https://doi.org/10.18690/um.fkkt.3.2022.1 ISBN 978-961-286-599-3 2 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. 1 Introduction The production of industrial y demanded and value added chemicals from renewable resources such as lignocel ulosic biomass is an extensively researched chal enge. Adipic acid is a dicarboxylic acid and one of the most important polymer precursors, in particular for the polyamide industry and sustainable processes are shought for its production. A newly developed strategy to produce adipic acid from lignocellulosic biomass is presented here. Lignocellulose-derived sugars, possessing six carbon atoms like adipic acid, are a promising starting point. They can be catalytical y oxidized into aldaric acids (e.g. mucic acid). Subsequently, the key reaction step is the selective catalytic dehydroxylation of mucic acid into adipic acid (Fig. 1). OH OH O OH OH O O HO O O OH O O O OH OH esterification O OH OH O dehydroxylation mucic acid in methanol in methanol hydrogenation oxidation O monosaccharide O O O O O O O (hemi)cel ulose O hydrogenation O O O Figure 1: Scheme of the renewable production of adipic acid via selective catalytic dehydroxylation of mucic acid. Sourec: own. Previously, Re-based homogeneous catalysts (e.g. CH3ReO3, HReO4 or KReO4) and alcohol solvents have successful y been used for this reaction (Shiramizu & Toste, 2012, 2013; Li et al. , 2014; Larson et al. , 2017). Fol owing the characteristic deoxydehydration route, pairs of vicinal hydroxyl groups are removed and a double bonds are formed. Further hydrogenation then yields adipic acid. To enable catalyst recycling, the use of solid catalyst in advantageous. Examples of heterogeneously catalyzed processes have been reported for similar reactants (Denning et al. , 2013; Ota et al. , 2015, 2016; Sandbrink et al. , 2016; Tazawa et al. , 2016; Nakagawa et al. , 2018; Sharkey et al. , 2018; Xi et al. , 2018). Only very recently, this was shown to be possible also for the case of adipic acid (Hočevar et al. , 2021), which F. M. Harth, B. Hočevar, B. Likozar, M. Grilc: A Novel Process to Produce Adipic Acid by Catalytic Dehydroxylation of Biomass-derived Mucic Acid 3. is presented here. The initial study, which also led to a patent application (Hočevar et al. , 2019), was soon confirmed by additional studies (Deng et al. , 2021; Jang et al. , 2021). Here, we present insights into how the Re-catalyzed dehydroxylation of mucic acid is influenced by various process parameters, including the type of Re catalyst, the role of the solvent, the influence of the presence of H2 gas and/or hydrogenation co-catalysts as wel as the effect of reaction temperature. 2 Materials and Methods Throughout the study, commercial catalysts were used: Re/C, Re/SiO2 and Re/Al2O3 (each 5 wt.-% Re loading, powders; Riogen, USA) as well as Pd/C (5 wt.-% Pd loading, powder; Sigma Aldrich, USA). Prior to catalytic experiments, the catalyst(s) were reduced in a flow of H2 (200 mL min-1) at 400 °C for 3 h. Catalytic experiments were conducted in stirred and heated autoclave reactors (Amar Equipment Pvt. Ltd., India). The reactor was loaded with mucic acid (97 % , Sigma Aldrich, USA), methanol and the catalyst(s), pressurized with nitrogen or hydrogen, heated up to the desired reaction temperature and kept for typical y 72 hours. Different commercially available catalysts (Re/C, Re/SiO2, Re/Al2O3) were tested. While there was always a solid Re catalyst present (typical y Re/C), in some experiments Pd/C was added as a co-catalyst. Moreover, the reaction conditions were varied, namely the reaction temperature in the range of 120-175 °C and the composition of the gas phase (nitrogen or hydrogen) prior to the catalytic experiments. The final reaction mixtures were filtered and analyzed by gas chromatography-mass spectrometry (GC-MS). A GCMS–QP 2010 Ultra (Shimadzu, Japan) was used equipped with a nonpolar column (ZebronTM ZB–5MSi, 60 m, diameter 0.25 mm, film thickness 0.25 μm). Compounds were identified by mass spectrometry and quantified based on external calibrations using the FID signal. 4 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. 3 Results and Discussion 3.1 Dehydroxylation over Re/C First, mucic acid dehydroxylation was investigated over a commercially available Re/C catalyst under inert N2 atmosphere. These results are shown in Fig. 2 (left columns). Since there is no H2 or other additional reducing agents are, methanol serves as the reducing agent. Moreover, methanol readily forms esters with mucic acid under reaction conditions. Consequently, al detected products are dimethyl esters of the respective dicarboxylic acids. The dehydroxylation reaction already proceeds at 120 °C, where ca. 93 % of dehydroxylated products were found after 72 hours reaction over Re/C. The main product is the twice-unsaturated analogue of dimethyl adipate (62 %), which is the direct product of ful deoxydehydration of mucic acid dimethyl ester, i.e. where al four vicinal hydroxyl groups are removed. Moreover, a considerable amount of this intermediate product was partial y hydrogenated to a group of isomers with one double bond (28 % yield) and some even ful y hydrogenated to dimethyl adipate. Increasing temperature to 175 °C lead to a slight increase in product yield (98 % of dehydroxylated products in total). More importantly, a shift in selectivity is apparent and only traces of the primary, twice-unsaturated product were found in the product mixture. While mostly partial y hydrogenated products were formed, there was also a substantial amount of dimethyl adipate (31 %). It was confirmed by gas chromatography that in both cases under initial y inert atmosphere the hydrogenation activity is related to H2 formation by methanol decomposition. When the initial gas phase composition in the reactor was changed from inert N2 to H2, hydrogenation activity is similarly enhanced (Fig. 2, right column). While under N2 atmosphere at 120 °C only around 30 % yield of hydrogenated products was formed over Re/C, under H2 pressure of initial y 10 bar al detected products were either partially (58 % yield) or ful y hydrogenated (25 %). These experiments prove that under suitable reaction conditions the combined dehydroxylation and subsequent hydrogenation of mucic acid to adipic acid derivatives is feasible. Moreover, product selectivity can be steered to a certain degree by the choice of the reaction conditions. F. M. Harth, B. Hočevar, B. Likozar, M. Grilc: A Novel Process to Produce Adipic Acid by Catalytic Dehydroxylation of Biomass-derived Mucic Acid 5. 100 N H 2 2 80 % 60 ield / 40 unsaturated (2x) Product y unsaturated (1x) 20 dimethyl adipate 0 120 °C 175 °C 120 °C Figure 2: Product yields after 72 h from mucic acid dehydroxylation in methanol over Re/C under different reaction conditions. Sourec: own. 3.2 Influence of catalyst support material Besides Re/C, two other commercially available Re-based catalysts were studied regarding their activity in mucic acid dehydroxylation (Fig. 3). It should be noted that, unlike for the previously discussed results, the catalysts were used as-obtained without reduction before the catalytic experiments. This explains the considerably lower hydrogenation activity over Re/C at 120 °C. Comparing Re/C with Re/SiO2 and Re/Al2O3 it is apparent that the latter two are by a factor of ca. 10 less active in catalyzing the dehydroxylation of mucic acid. Moreover, Re/Al2O3 was found to rather catalyze undesired decarboxylation and hydrodeoxygenation reactions resulting in the formation of short-chain as well as cyclization products. Overall, Re/C is exceptional y suited as a catalyst for the dehydroxylation reaction. 6 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. 100 unsaturated (2x) 80 unsaturated (1x) dimethyl adipate % 60 120 °C 140 °C ield / 40 Product y 20 0 Re Re Re /S /A /C Re Re Re iO l /S /A /C i 2 O O l 2 3 2 O 2 3 Figure 3: Product yields after 72 h from mucic acid dehydroxylation in methanol over different solid Re catalysts under H2 atmosphere at different temperatures. Sourec: own. 2.3 Influence of a hydrogenation co-catalyst The formation of the twice-unsaturated dehydroxylation product proceeds considerably more facile over Re/C than the subsequent hydrogenation reactions, as was shown in section 2.1. Therefore, the addition of a hydrogenation co-catalyst is one option to increase selectivity for hydrogenated products, in particular dimethyl adipate, without resorting to harsher reaction conditions. The results in Fig. 4 clearly show that the presence of additional Pd/C (molar ratios nPd nRe-1 = 1:6 or 1:4) shifts product selectivity almost completely towards ful y hydrogenated dimethyl adipate. Yields of up to 60 % were obtained with only ca. 3 % of unsaturated products. Therefore, the use of Pd/C as a hydrogenation co-catalyst facilitates hydrogenation and enables the efficient one-pot dehydroxylation and hydrogenation of mucic acid into adipic acid. F. M. Harth, B. Hočevar, B. Likozar, M. Grilc: A Novel Process to Produce Adipic Acid by Catalytic Dehydroxylation of Biomass-derived Mucic Acid 7. 100 unsaturated (1x) 80 dimethyl adipate % 60 ield / 40 Product y 20 0 Re Re Re /C /C /C + + Pd/C Pd/C (6: (4: 1) 1) Figure 4: Product yields after 72 h from mucic acid dehydroxylation in methanol over Re/C with or without co-catalyst Pd/C under H2 atmosphere at 120 °C. Sourec: own. 4 Conclusions The use of solid Re-based catalysts for the dehydroxylation of mucic acid in coimbination with subsequent hydrogenation to adipic acid was investigated. One important aspect is the use of methanol as a solvent that also protects the carboxylic groups by esterification and can serve as a reducing agent and a H2 source. Re/C was shown to be a highly efficient catalyst for the heterogeneously catalyzed dehydroxylation reaction, in particular compared to other solid Re catalysts. Moreover, the reaction conditions and the presence or absence of an additional Pd/C hydrogenation catalyst are influential parameters that al ow to steer product selectivity of the process. Under N2 atmosphere, methanol serves as reducing agent and mostly the direct dehydroxylation product, which contains two double bonds, is obtained over Re/C at 120 °C in yields of up to 62 %. Overall, the yield of dehydroxylated product was up to 98 %. This includes also partially hydrogenated as wel as ful y hydrogenated products, the latter being the target product dimethyl adipate. These subsequent hydrogenation reactions are enhanced by higher reaction temperature, H2 atmosphere as wel as the use of a Pd/C co-catalyst. Adjusting the reaction conditions in this manner al ows for selective production of dimethyl adipate from biomass-derived mucic acid. Due to the heterogeneous catalytic nature 8 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. of the process, which enables catalyst recycling, as wel as the non-toxic and renewable reactants the presented process is a considerable improvement compared to conventional processes for the production of adipic acid. Acknowledgments This work was funded by the Slovenian Research Agency (ARRS) under core funding P2-0152 and postdoctoral project Z2-9200. Furthermore, funding from the Young Researchers Programme from ARRS is acknowledged. References Deng, W. et al. (2021) ‘Efficient Catalysts for the Green Synthesis of Adipic Acid from Biomass’, Angewandte Chemie International Edition, 60(9), pp. 4712–4719. doi: 10.1002/anie.202013843. Denning, A. L. et al. (2013) ‘Deoxydehydration of glycols catalyzed by carbon-supported perrhenate’, ChemCatChem, 5(12), pp. 3567–3570. doi: 10.1002/cctc.201300545. Hočevar, B. et al. (2021) ‘H2‐Free Re‐Based Catalytic Dehydroxylation of Aldaric Acid to Muconic and Adipic Acid Esters’, Angewandte Chemie International Edition, 60(3), pp. 1244–1253. doi: 10.1002/anie.202010035. Hočevar, B. et al. (2019) ‘Sustainable process for producing muconic, hexenedioic and adipic acid (and their esters) from aldaric acids by heterogeneous catalysis’. European Patent Application EP 3782976A1, European Patent Office. Jang, J. H. et al. (2021) ‘A Heterogeneous Pt-ReOx/C Catalyst for Making Renewable Adipates in One Step from Sugar Acids’, ACS Catalysis, 11(1), pp. 95–109. doi: 10.1021/acscatal.0c04158. Larson, R. T. et al. (2017) ‘Hydrogen Gas-Mediated Deoxydehydration/Hydrogenation of Sugar Acids: Catalytic Conversion of Glucarates to Adipates’, Journal of the American Chemical Society, 139(40), pp. 14001–14004. doi: 10.1021/jacs.7b07801. Li, X. et al. (2014) ‘Highly efficient chemical process to convert mucic acid into adipic acid and DFT studies of the mechanism of the rhenium-catalyzed deoxydehydration’, Angewandte Chemie - International Edition, 53(16), pp. 4200–4204. doi: 10.1002/anie.201310991. Nakagawa, Y. et al. (2018) ‘Mechanistic Study of Hydrogen-Driven Deoxydehydration over Ceria-Supported Rhenium Catalyst Promoted by Au Nanoparticles’, ACS Catalysis, 8(1), pp. 584– 595. doi: 10.1021/acscatal.7b02879. Ota, N. et al. (2015) ‘Hydrodeoxygenation of vicinal OH groups over heterogeneous rhenium catalyst promoted by pal adium and ceria support’, Angewandte Chemie - International Edition, 127(6), pp. 1897–1900. doi: 10.1002/ange.201410352. Ota, N. et al. (2016) ‘Performance, Structure, and Mechanism of ReOx-Pd/CeO2 Catalyst for Simultaneous Removal of Vicinal OH Groups with H2’, ACS Catalysis, 6(5), pp. 3213–3226. doi: 10.1021/acscatal.6b00491. Sandbrink, L. et al. (2016) ‘ReOx/TiO2: A Recyclable Solid Catalyst for Deoxydehydration’, ACS Catalysis, 6(2), pp. 677–680. doi: 10.1021/acscatal.5b01936. Sharkey, B. E. et al. (2018) ‘New solid oxo-rhenium and oxo-molybdenum catalysts for the deoxydehydration of glycols to olefins’, Catalysis Today. Elsevier, 310(May 2017), pp. 86–93. doi: 10.1016/j.cattod.2017.05.090. Shiramizu, M. & Toste, F. D. (2012) ‘Deoxygenation of biomass-derived feedstocks: Oxorhenium-catalyzed deoxydehydration of sugars and sugar alcohols’, Angewandte Chemie - International Edition, 51(32), pp. 8082–8086. doi: 10.1002/anie.201203877. Shiramizu, M. & Toste, F. D. (2013) ‘Expanding the scope of biomass-derived chemicals through tandem reactions based on oxorhenium-catalyzed deoxydehydration’, Angewandte Chemie - International Edition, 52(49), pp. 12905–12909. doi: 10.1002/anie.201307564. F. M. Harth, B. Hočevar, B. Likozar, M. Grilc: A Novel Process to Produce Adipic Acid by Catalytic Dehydroxylation of Biomass-derived Mucic Acid 9. Tazawa, S. et al. (2016) ‘Deoxydehydration with Molecular Hydrogen over Ceria-Supported Rhenium Catalyst with Gold Promoter’, ACS Catalysis, 6(10), pp. 6393–6397. doi: 10.1021/acscatal.6b01864. Xi, Y. et al. (2018) ‘Mechanistic study of the ceria supported, re-catalyzed deoxydehydration of vicinal OH groups’, Catalysis Science and Technology. Royal Society of Chemistry, 8(22), pp. 5740–5752. doi: 10.1039/c8cy01782d. 10 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. ONE-POT ALGAE CONVERSION INTO SUSTAINABLE BIOFUEL BY CATALYTIC HYDROPROCESSING DANA MARINIČ, BRIGITA HOČEVAR, MIHA GRILC, BLAŽ LIKOZAR National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering, Ljubljana, Slovenia dana.marinic@ki.si, brigita.hocevar@ki.si, miha.grilc@ki.si, blaz.likozar@ki.si Abstract Microalgae have emerged as a promising feedstock for third generation biofuels. This study aims to investigate the reaction conditions for biodiesel production from microalgae. Microalgae were liquefied and transformed into a mixture of diesel like hydrocarbons using commercial bifunctional NiMo/γ-Al2O3 catalyst. GC-MS analysis revealed that the produced bio-oils are a complex mixtures of partially or completely deoxygenated Keywords: compounds. The most promising experiment using 25 wt% of adipic acid, catalyst at 350 °C of reaction temperature and 50 bar of initial biomass, hydrogen pressure yielded 22.6 wt% of liquid alkanes with the high dehydroxylation, heterogeneous selectivity towards pentadecane, hexadecane, heptadecane and catalysis, octadecane. rhenium DOI https://doi.org/10.18690/um.fkkt.3.2022.2 ISBN 978-961-286-599-3 12 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. 1 Introduction Environmental problems among with the increasing energy demand, instable fuel prices and limited fossil fuel have led to the growing interest in renewable fuels. Expensive raw materials and consequently higher biodiesel price compared to petroleum fuels represent the main obstacle for general use of biofuels. Microalgae have recently emerged as an attractive and suitable feedstock for biofuel production, mostly because of its high biomass productivity and photosynthetic efficiency. Furthermore, microalgae exhibit high growth rate and high accumulation capacity of lipids and fatty acids. Moreover, it can grow on waste, it does not require arable land of fresh water, hence it’s not a threat to traditional agricultural goods. Low carbon footprint and GHG emissions make biofuel technology even more interesting (Bwapwa et al., 2017; Delrue et al., 2013). The advantage of having high tolerance to CO2 makes microalgae a promising organism for CO2 mitigation. (Moreira & Pires, 2016). The algal biofuel technology has been the subject of numerous studies throughout the previous decade. The three principal bio-fuel pathways used for the biofuel production are pyrolysis, the lipid extraction and conversion into bio-diesel through transesterification and the hydrothermal liquefaction (HTL). The latter was developed to be the most practical one due to the algal high water content (Yang et al., 2016). In comparison to HTL, which can convert biomass with high moisture content (above 50% mass fraction), pyrolysis can decompose only dry organic matter (Hognon et al., 2015). Additional drying cause high electricity and heat consumption (Delrue et al., 2012). HTL is a thermochemical process, where the biomass is transformed directly into liquid biocrude while using high pressures (10-25 MPa) and temperatures (280-370 °C) for 5-120 minutes (Xu et al., 2018). Due to the high oxygen and nitrogen concentrations in bio-crude and consequently poor product quality, further catalytic hydrotreatment is required (Yang et al., 2016). Additional treatment leads to the energy, time and cost prohibitive processes, which limits the options for general use. Since high pressure and temperature are already some of the major HTL drawbacks (Delrue et al., 2013), the improvement is necessary. In this study the one-pot algae D. Marinič, B.Hočevar, M. Grilc, B. Likozar: One-pot Algae Conversion Into Sustainable Biofuel by Catalytic Hydroprocessing 13. conversion into sustainable biofuel was carried out by catalytic hydroprocessing. The main goal was to combine liquefaction and hydrotreatment processes. This study is a part of a bilateral research project in collaboration with the French Alternative Energies and Atomic Energy Commission (CEA). Microalgae cultivation, harvesting and lipid extraction was done by CEA. Our department at the National Institute of Chemistry carried out the hydrotreatment of microalgae oils. 2 Methods The catalytic hydrotreatment of Chlorel a microalgae was performed in a 300 mL cylindrical stainless steel slurry reactor equipped with a Rushton turbine impel er (Fig. 1). The reactor was filled with 120 mL of reaction mixture that contained 5 wt% of algae, the rest being dodecane. Commercial y available NiMo/Al2O3 catalyst was used in this study. The catalyst mass was set to 25 wt% with respect to the initial mass of microalgae. The system was purged with nitrogen twice to ensure inert gaseous headspace and then pressurized with hydrogen to the desired pressure (Table 1). The reaction mixture was heated-up by increasing the temperature from room temperature with the heating ramp of 5 °C/min to the desired reaction temperature. The reaction conditions were maintained constant for 4 hours before rapid cooling down. Decompressed gas phase from the reactor was analyzed by micro-GC. Before opening, the reactor was purged with nitrogen. The reaction mixture was filtered. The solid samples col ected from the filtration were washed three times with dodecane and once with hexane, then analyzed by Fourier transform infrared (FTIR) spectroscopy. The liquid samples collected from the filtration were analyzed by Gas Chromatography − Mass spectroscopy (GC-MS, Shimadzu Ultra 2010) and by FTIR. 14 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. Figure 1: 300 mL high-temperature and high-pressure reactor. Source: own. Table 1: Reaction conditions for each run in batch slurry reactor. Run Catalyst form Ta (°C) Pb (bar) Wcat (wt%) 1 Sulf NiMo/γ-Al2O3 200 50c 25 2 Sulf NiMo/γ-Al2O3 300 50c 25 3 Sulf NiMo/γ-Al2O3 312 50c 25 4 Sulf NiMo/γ-Al2O3 325 50c 25 5 Sulf NiMo/γ-Al2O3 350 50c 25 6 Sulf NiMo/γ-Al2O3 325 30c 25 7 Sulf NiMo/γ-Al2O3 325 20c 25 8 Sulf NiMo/γ-Al2O3 325 50d 25 9 Sulf NiMo/γ-Al2O3 350 30c 25 10 Sulf NiMo/γ-Al2O3 350 20c 25 11 Ox NiMo/γ-Al2O3 325 50c 25 12 Red NiMo/γ-Al2O3 325 50c 25 13 / 325 50c 0e 14 / 325 50c 0f a Set temperature of plateau. b Initial pressure in reactor. c Hydrogen atmosphere. d Nitrogen atmosphere. e Blank – no catalyst f Blank – no algae and catalyst D. Marinič, B.Hočevar, M. Grilc, B. Likozar: One-pot Algae Conversion Into Sustainable Biofuel by Catalytic Hydroprocessing 15. 3 Results 3.1 Liquid phase analysis GC-MS analysis revealed that the produced bio-oils are a complex mixtures of partial y or completely deoxygenated compounds. The most promising experiment using 25 wt% of catalyst at 350 °C of reaction temperature and 50 bar of initial hydrogen pressure yielded 22.6 wt% of liquid alkanes with respect to the initial mass of microalgae. The results showed high reaction selectivity towards pentadecane, hexadecane, heptadecane and octadecane. The chromatogram shown in Fig. 2 confirmed low oxygen and nitrogen content, where the main oxygen compound was nonadecanol. The removal of unwanted heteroatom compounds was reached by hydrodeoxygenation (HDO). Hydrogenation and hydrogenolysis reactions transform oxygen composed molecules into o-free hydrocarbon chains, which are suitable for the use as biofuel (Valencia et al., 2018). Figure 2: GC-MS chromatogram of produced biooil at optimal reaction conditions (350 °C and 50 bar of initial hydrogen pressure). Source: own. Higher temperature resulted in higher alkane concentration (up to 4,53 mg/ml) and higher yields (up to 22.6 wt%). The higher the hydrogen pressure, the more hydrogenation reactions of alkenes occurred. In addition, stricter reaction conditions (such as higher temperature and higher hydrogen pressure) resulted in lower mass residue, suggesting that the liquefaction was more intense. 16 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. NiMo/Al2O3 is being widely used as a commercial catalyst in petrochemical industry. Among the reduced, oxygenated and sulfided form, the latter was found to be the most promising, while the first two were much less active. GC-MS chromatogram of produced biooils using different catalyst form is presented in Fig. 3. Figure 3: GC-MS chromatogram of produced biooils using reduced, oxygenated and sulfided catalyst form. Source: own. The FTIR spectra of liquid (Fig. 4) and solid samples were obtained in the range of 4500 – 400 cm─1 for determining the functional groups present in the feedstock and the product. FTIR spectrum of liquid product match quite well with the spectrum of the dodecane, since the solvent represents a high proportion of the product. The major difference were two weak bands around 3700 cm─1 and 1070 cm─1 which are related to O─H stretching vibration. D. Marinič, B.Hočevar, M. Grilc, B. Likozar: One-pot Algae Conversion Into Sustainable Biofuel by Catalytic Hydroprocessing 17. Figure 4: FTIR analysis results of produced biooils. Source: own. 3.1 Gas phase analysis Gas products were mostly composed of H20, CO, CO2 and light hydrocarbons such as CH4 and C2H6. Fatty acids under hydrogen pressure can undergo three main deoxygenation routes; hydrodeoxygenation, decarbonylation or decarboxylation. From the gas composition we can conclude that hydrodeoxygenation (removal of O atoms as H2O) is more dominant deoxygenation pathway than decarbonylation and decarboxylation (DCO, removal of O atoms as CO and CO2) (Arora et al., 2021; Soni et al., 2017; Yang et al., 2016). 4 Conclusion Microalgae slurry was successful y processed in a cylindrical reactor at temperature of 300 – 350 °C, hydrogen pressure of 20 – 50 bar and reaction times of 4 hours. The catalytic hydroprocessing led to the conversion of microalgae into a complex mixture of diesel like hydrocarbons (C14–C18). The oil yields were higher (up to 22.6 wt%) at higher temperature and H2 pressure. 18 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. Acknowledgments This work was funded by the Slovenian Research Agency (ARRS) under core funding P2-0152 and project NC-0013. References Arora, P., Abdolahi, H., Cheah, Y. W., Salam, M. A., Grennfelt, E. L., Rådberg, H., Creaser, D., & Olsson, L. (2021). The role of catalyst poisons during hydrodeoxygenation of renewable oils. Catalysis Today, 367, 28–42). doi:10.1016/j.cattod.2020.10.026 Bwapwa, J. K., Anandraj, A., & Trois, C. (2017). Possibilities for conversion of microalgae oil into aviation fuel: A review. Renewable and Sustainable Energy Review s, 80, 1345–1354. doi:10.1016/j.rser.2017.05.224 Delrue, F., Li-Beisson, Y., Setier, P.-A., Sahut, C., Roubaud, A., Froment, A.-K., & Peltier, G. (2013). Comparison of various microalgae liquid biofuel production pathways. Bioresource Technology, 136, 205–212. doi:10.1016/j.biombioe.2014.11.025 Delrue, Setier, P. A., Sahut, C., Cournac, L., Roubaud, A., Peltier, G., & Froment, A. K. (2012). An economic, sustainability, and energetic model of biodiesel production from microalgae. Bioresource Technolog y, 111, 191–200. doi:10.1016/j.biortech.2012.02.020 Hognon, C., Delrue, F., Texier, J., Grateau, M., Thiery, S., Mil er, H., & Roubaud, A. (2015). Comparison of pyrolysis and hydrothermal liquefaction of Chlamydomonas reinhardti . Growth studies on the recovered hydrothermal aqueous phase. Biomass and Bioenergy, 73, 23– 31. doi:10.1016/j.biombioe.2014.11.025 Kim, T.-H., Lee, K., Kim, M. Y., Chang, Y. K., & Choi, M. (2018). Effects of Fatty Acid Compositions on Heavy Oligomer Formation and Catalyst Deactivation during Deoxygenation of Triglycerides. ACS Sustainable Chem. Eng., 6, 17168–17177. doi:10.1021/acssuschemeng.8b04552 Moreira, D., & Pires, J. C. M. (2016). Atmospheric CO2 capture by algae: Negative carbon dioxideemission path. Bioresource Technology, 215, 371–379. doi:10.1016/j.biortech.2016.03.060 Soni, V. K., Sharma, P. R., Choudhary, G., Pandey, S., & Sharma, R. K. (2017). Ni/Co-Natural Clay as Green Catalysts for Microalgae Oil to Diesel-Grade Hydrocarbons Conversion. ACS Sustainable Chemistry and Engineering, 5, 5351–5359. doi:10.1021/acssuschemeng.7b00659 Valencia, D., García-Cruz, I., Uc, V. H., Ramírez-Verduzco, L. F., Amezcua-Al ieri, M. A., & Aburto, J. (2018). Unravel ing the chemical reactions of fatty acids and triacylglycerides under hydrodeoxygenation conditions based on a comprehensive thermodynamic analysis. Biomass and Bioene rgy, 112, 37–44. doi:10.1016/j.biombioe.2018.02.014 Xu, D., Lin, G., Guo, S., Wang, S., Guo, Y., & Jing, Z. (2018). Catalytic hydrothermal liquefaction of algae and upgrading of biocrude: A critical review. Renewable and Sustainable Energy Reviews, 97, 103–118. doi:10.1016/j.rser.2018.08.042 Yang, C., Li, R., Cui, C., Liu, S., Qiu, Q., Ding, Y., Wu, Y., & Zhang, B. (2016). Catalytic hydroprocessing of microalgae-derived biofuels: a review. Green Chemistry, 18, 3684–3699. doi:10.1039/c6gc01239f DEVELOPMENT OF FT–IR, UV AND FLUORESCENCE BASED ANALYTICAL METHODOLOGY FOR LIGNIN CHARACTERISATION ROK POGOREVC, TINA ROČNIK, BLAŽ LIKOZAR, EDITA JASIUKAITYTĖ-GROJZDEK, MIHA GRILC National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering, Ljubljana, Slovenia tina.rocnik@ki.si, blaz.likozar@ki.si, edita.jasiukaityte@ki.si, miha.grilc@ki.si Abstract The development of the novel analytical methodologies for lignin chracterisation is presented. Lignin fractions were characterized by NMR, SEC/GPC as wel new analytical methodologies were implemented such as FT–IR, UV and fluorescence. FT–IR and fluorescence results show a promising correlation to the NMR and SEC/GPC analysis. Main findings from the SEC/GPC and NMR results indicates that by adding more water to the organosolv spent liquor isolated lignin contains lower amount of β-O 4 linking motif and also has a lower molecular weight. The following is also confirmed by the Keywords: lignin, straightforward analysis using FT–IR and fluorescence giving the molecular opportunity to replace time-consuming and complex lignin weight, characterisation methods with a simple and quick analytics and the FT–IR spectroscopy, possibility to be applied for the in-process control in continuous fractionation, production processes. UV DOI https://doi.org/10.18690/um.fkkt.3.2022.3 ISBN 978-961-286-599-3 20 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. 1 Introduction Lignocel ulosic biomass, one of the renewable resources representing an alternative to fossil oil and gas, is composed of cellulose (50 %-source of carbohydrates), hemicellulose (25 %-source of carbohydrates) and lignin (25 %) which could be used in production of biofuels, chemical, biopolymers and sugars (Liao et al., 2020; Liu et al., 2018). Lignin is a by-product of pulp and paper industry processes (kraft, sulfite and soda) and is usual y burned to produce energy for the pulping but it could be used to produce value added chemicals and fuels by reducing its heterogeneity and overall molecular weight (Liao et al., 2020; Pang et al., 2021; Sadeghifar et al., 2020; Yáñez-S et al., 2014). More environmental y friendly organosolv process coupled with a certain lignin recovery/fractionation protocol is a promising way to isolate lignin with a particular properties (molecular weight and structural features). Several fractionation processes using different solvents have been developed (Liu et al., 2018). Lignin is synthetized via radical polymerization using three monolignols, specifically sinapyl alcohol (syringyl (S)), coniferyl alcohol (guaiacyl (G)) and p-coumaryl alcohol (H), inside the plants such as softwood (mostly G units are present), hardwood (G and S units are present), and some grasses (al three of the units are present (H, G and S)) (Lahive et al., 2020; Liao et al., 2020; Liu et al., 2018; Pang et al., 2021). During the polymerization monolignols are coupled forming specific lignin motifs such as β-O-4, β-5 and β-β (Lahive et al., 2020). Conventional y used analytics in lignin chemistry Nuclear Magnetic Resonance (NMR) and Size-Exclusion Chromatography (SEC)/ Gel-Permeation Chromatography (GPC) are complex and time-consuming. NMR provides information on lignin structural properties, but the sample preparation and analysis by itself are quite long. SEC/GPC provides the molecular weight of lignin, but again sample preparation takes even more time, because of the derivatization procedure. New analytical methodologies has to be developed for lignin characterization to get particular information faster and easier (Zevallos Torres et al., 2020). R. Pogorevc, T. Ročnik, B. Likozar, E. Jasiukaitytė-Grojzdek, M. Grilc: Development of FT–IR, UV and Fluorescence Based Analytical Methodology for Lignin Characterisation 21. The aim of this paper is to characterize lignin fractions with new analytical methodologies such as UV-vis, fluorescence and Fourier-transform infrared spectroscopy (FT–IR) and to establish a relationship with the conventional y used analytics in lignin chemistry such as NMR and SEC/GPC. 2 Methods Delignification of beech wood was made in 300 mL reactor (Autoclave engineering, Figure 1) at around 150 °C using mixture of solvents (ethanol and water) and diluted sulfuric acid. Filtration of the cold reaction mixture was then applied followed by drying solid residue in the oven and fractionation of the filtered liquid by adding various volumes of water to recover lignin with specific molecular weight. Recovered lignin was then freeze-dried and characterized using NMR, SEC/GPC, FT–IR , UV and fluorescence. FT–IR spectra were recorded on FT–IR-ATR spectrophotometer (PerkinElmer, Spectrum Two), in the region 4000-400 cm-1 with resolution of 4 cm-1 and accumulation 64. The average spectrum of the ten paralel measurements of each sample was considered as a representative spectrum. Molecular weights of derivatized lignin samples were determined using size-exclusion chromatographic system (Thermo Scientific Ultimate 3000, ThermoFisher) equipped with UV detector set at 280 nm using THF as an eluent and Plgel 5 µm MIXED D 7.5 × 300 mm column. Calibration was performed using PS standards. NMR spectra were recorded using a Bruker AVANCE NEO 600 MHz NMR spectrometer following the protocol reported by Tran et al. (Tran et al., 2015). Fluorescence spectra in spectral range of 300 nm to 530 nm with emission step 2 nm was recorded on a Synergy H1 microplate reader (Biotek). 22 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. Figure 1: Autoclave Engineering. Source: own. 3 Results SEC/GPC chromatogram profiles (Figure 2a) show higher molecular weights at the fraction 1 (lowest amount of water was added) compared to fraction 5 (the highest amount of water was added). Using water as an anti-solvent it is possible to separate lignins with the specific properties, for instance average molecular weight. Initial lignin was used as a reference and was isolated adding the excess volume of the anti-solvent. Figure 1: a) molecular weight distributions of the isolated lignins, b) enlarged FT–IR spectrum between 800 cm-1 and 1800 cm-1 of the initial lignin and three fractions. Source: own. R. Pogorevc, T. Ročnik, B. Likozar, E. Jasiukaitytė-Grojzdek, M. Grilc: Development of FT–IR, UV and Fluorescence Based Analytical Methodology for Lignin Characterisation 23. FT–IR analysis identifies β-O-4 linkage with a corresponding signal around 1030 cm-1 from which the assumption of the number/quantity of it was made (Yáñez-S et al., 2014). The comparison of FT–IR spectra (Fig. 2b) shows a clear increase of the signal at 1026 cm-1 from last (F5) to first (F1) fraction which indicates higher content of this linking motif in F1 then in F5 (Yáñez-S et al., 2014). The comparison of the transmittance perversely mentioned signal with integrated surface of signal in NMR spectra which are 14.0, 12.9 and 8.5 per 100 C9 units, for F1, F3 and F5 fractions respectively, show similar pattern (lower integrated number higher transmittance) meaning those two analyses can be correlated. Combination of fluorescence and SEC/GPC (Fig. 3) analysis indicates that the maximum intensity at 320 - 330 nm is align with the molecular weight which could be used to calculate the approximate molecular weight of initial or any other lignin isolated using EtOH/water organosolv pulping. F5 24000 a 24000 b F5 F4 20000 Initial 20000 F4 Lignin 16000 F3 U 16000 FU 12000 F2 R F1 RF 12000 F3 8000 4000 8000 F2 F1 0300 350 400 450 500 1000 2000 3000 4000 5000 6000 7000 M Wavelength (nm) w (Da) Figure 3: a) fluorescence measurements of initial lignin and al fractions. b) highlighted maximum values are used to correlate fluorescence and SEC analytical data Source: own. 4 Conclusion Straightforward FT–IR, fluorescence analysis show a promising correlation with NMR and SEC analytical data when used for lignin characterisation. The outstanding relationship between fluorescence and SEC analysis could be used for the in-process control in continuous production processes, for instance isolating specific lignin/fractions. Further, the SEC-fluorescence relationship will certainly be applied 24 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS. for the development of more complex analytical methodologies including UV, FT–IR and NMR analytical data. Acknowledgments This work was funded by the Slovenian Research Agency (ARRS) under core funding P2-0152, infrastructure core funding IO-0003 and project J2-2492. References Lahive, C. W., Kamer, P. C. J., Lancefield, C. S., & Deuss, P. J. (2020). An Introduction to Model Compounds of Lignin Linking Motifs; Synthesis and Selection Considerations for Reactivity Studies. ChemSusChem, 13, 4238–4265. doi:10.1002/CSSC.202000989 Liao, J. J., Abd Latif, N. H., Trache, D., Brosse, N., & Hussin, M. H. (2020). Current advancement on the isolation, characterization and application of lignin. International Journal of Biological Macromolecules, 162, 985–1024. doi:10.1016/j.ijbiomac.2020.06.168 Liu, C., Si, C., Wang, G., Jia, H., & Ma, L. (2018). A novel and efficient process for lignin fractionation in biomass-derived glycerol-ethanol solvent system. Industrial Crops and Products, 111, 201–211. doi:10.1016/j.indcrop.2017.10.005 Pang, T., Wang, G., Sun, H., Sui, W., & Si, C. (2021). Lignin fractionation: Effective strategy to reduce molecule weight dependent heterogeneity for upgraded lignin valorization. Industrial Crops and Products, 165, 1-18. doi:10.1016/j.indcrop.2021.113442 Sadeghifar, H., Sadeghifar, H., Ragauskas, A., Ragauskas, A., Ragauskas, A., & Ragauskas, A. (2020). Perspective on Technical Lignin Fractionation. ACS Sustainable Chemistry and Engineering, 8, 8086–8101. doi:10.1021/acssuschemeng.0c01348 Tran, F., Lancefield, C. S., Kamer, P. C. J., Lebl, T., & Westwood, N. J. (2015). Selective modification of the β–β linkage in DDQ-treated Kraft lignin analysed by 2D NMR spectroscopy. Green Chemistry, 17, 244. doi:10.1039/c4gc01012d Yáñez-S, M., Matsuhiro, B., Nuñez, C., Pan, S., Hubbel , C. A., Sannigrahi, P., & Ragauskas, A. J. (2014). Physicochemical characterization of ethanol organosolv lignin (EOL) from Eucalyptus globulus: Effect of extraction conditions on the molecular structure. Polymer Degradation and Stability, 110, 184–194. doi:10.1016/j.polymdegradstab.2014.08.026 Zeval os Torres, L. A., Lorenci Woiciechowski, A., de Andrade Tanobe, V. O., Karp, S. G., Guimarães Lorenci, L. C., Faulds, C., & Soccol, C. R. (2020). Lignin as a potential source of high-added value compounds: A review. Journal of Cleaner Production, 263, 1–18. doi:10.1016/j.jclepro.2020.121499 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGIES & BUSINESS MODELS FOR CIRCULAR ECONOMY: CONFERENCE PROCEEDINGS SANJA POTRČ, MILOŠ BOGATAJ, ZDRAVKO KRAVANJA, ZORKA NOVAK PINTARIČ (EDS.) University of Maribor, Faculty of Chemistry and Chemical Engineering, Maribor, Slovenia sanja.potrc@um.si, milos.bogataj@um.si, zdravko.kravanja@um.si, zorka.novak@um.si Abstract The 4th International Conference on Technologies & Business Models for Circular Economy (TBMCE) was organized by the Faculty of Chemistry and Chemical Engineering, University of Maribor in collaboration with the Strategic Research and Innovation Partnership - Networks for the Transition into Circular Economy (SRIP- Circular Economy). The conference was held in Portorož, Slovenia, at the Grand Hotel Bernardin from September 13th to September 15th, 2021. TBMCE 2021 was devoted to presentations of circular economy concepts, technologies and methodologies that contribute to the shift of business entities and Keywords: society as a whole to a more responsible, circular management of sircular resources. The conference program included panel discussions, economy, plenary and keynote sessions, oral and poster presentations on the sustainable development, following topics: Sustainable energy, Biomass and alternative raw processes and materials, Circular business models, Secondary raw materials and technologies, functional materials, ICT in Circular Economy, Processes and circular business models, technologies. The event was under the patronage of Ministry of research and Economic Development and Technology. development DOI https://doi.org/10.18690/um.fkkt.3.2022 ISBN 978-961-286-599-3 Document Outline 2.3 Influence of a hydrogenation co-catalyst