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Project description:

Project no:
Synthesis and structure-activity relationship of catalysts for dehydration of biogenic methanol
1st project leader:
Pitter, Stephan - Karlsruhe Institute of Technology (KIT), Institute of Catalysis Research and Technology, Karlsruhe
2nd project leader
Sauer , Jörg - Karlsruhe Institute of Technology (KIT), Institute of Catalysis Research and Technology, Karlsruhe
Dimethyl ether (DME) is an intermediate for bioeconomy with growing importance because it can be produced with high efficiency through gasification of residual biomass and subsequent catalytic conversion. It can also be used as an alternative to diesel and liquefied petroleum gas (LPG).[1-2] DME is a well-known ozone-friendly propellant [3] and a key intermediate in the production of important chemicals such as lower olefins, dimethyl sulphate and methyl acetate.[4-8] KIT has been active in the investigation of related catalytic processes and the development of systems for energy conversion. Conversion of CO-rich synthesis gas, generated from biomass, to DME and further conversion to olefins and fuels have been studied for several years.[1,9-10] In particular the subsequent conversion of DME into fuel-suitable hydrocarbons has been subject of recent studies at KIT.[1,11,12]
DME can be synthesized directly from synthesis gas using a dual catalyst system that typically consists of a Cu-based catalyst and a solid acid catalyst [9,10,13] or by methanol dehydration via solid acid catalysts from 200 °C at slightly increased pressure.[14] Among the different types of solid acids used for methanol dehydration, H-ZSM-5 and γ Al2O3 in particular have been intensively investigated both on a laboratory and on commercial scale. H-ZSM-5 is more active than γ-Al2O3 according to the present state of knowledge, but is subject to faster deactivation with the formation of undesired hydrocarbons. On the other hand, γ-Al2O3 is more selective towards DME, but has disadvantages such as reduced activity and rapid deactivation in the presence of water. Recently, the suitability of ordered mesoporous materials has been reported.[15] Due to their high surfaces, regular frameworks and large pore size with narrow distribution as catalysts, their effectiveness has been investigated. These findings are to be systematically extended to other compound classes in the planned doctoral project, in particular to types of hierarchical zeolites developed at the IKFT for several years now.[11, 12]

The project is divided into three main experimental tasks:
• Synthesis of dehydration catalysts (new solid acids or modification of commercial materials) with enhanced water tolerance and stability
• Experimental study of catalytic methanol dehydration at laboratory scale (individually as well as in direct DME synthesis)
• Comprehensive characterization of materials, especially by means of surface analytical methods
From the experimental findings, structure-activity-stability relationships are to be derived, based also on deactivation accompanied by light hydrocarbons formation and the distinct role of water. The expected results will support the development of a process on an enlarged scale in which synthesis gas (H2 from electrolysis, CO/CO2 from biogenic residues) is converted into DME and derived products.

Depending on the qualification of the candidate, the doctorate will be obtained at the KIT Faculty of Chemical Engineering or the KIT Faculty of Chemistry and Biosciences.
[1] N. Dahmen, J. Abeln, M. Eberhard, T. Kolb, H. Leibold, J. Sauer, D. Stapf, B. Zimmerlin, WIREs Energy and Environment, 6 (2017) 1-10.

[2] T.V.W. Janssens, P.L.T. Gabrielsson, C. Duwig, S.E. Mikkelsen, in, Haldor Topsoe A/S, 2013.

[3] K. Omata, Y. Watanabe, T. Umegaki, G. Ishiguro, M. Yamada, Fuel, 81 (2002) 1605-1609.

[4] N.V. Kolesnichenko, L.E. Kitaev, Z.M. Bukina, N.A. Markova, V.V. Yushchenko, O.V. Yashina, G.I. Lin, A.Y. Rozovskii, Kinet. Katal, 48 (2007) 789-

[5] M. Zimmermann, T.N. Otto, B. Powietzka, D. Neumann-Walter, CIT., 87 (2015) 1748-1759.

[6] Y. Adachi, M. Komoto, I. Watanabe, Y. Ohno, K. Fujimoto, Fuel, 79 (2000) 229-234.

[7] S.P. Naik, T. Ryu, V. Bui, J.D. Miller, N.B. Drinnan, W. Zmierczak, Chem. Eng. J., 167 (2011) 362-368.

[8] DME Handbook, Japan DME Forum, 2007.

[9] M. Stiefel, R. Ahmad, U. Arnold, M. Döring, Fuel Process. Technol., 92 (2011) 1466-1474.

[10] R. Ahmad, D. Schrempp, S. Behrens, J. Sauer, M. Döring, U. Arnold, Fuel Process. Technol., 121 (2014) 38-46.

[11] S. Wodarz et al., submitted

[12] M. C. Zimmermann, T. N. Otto, S. Wodarz, T. A. Zevaco, S. Pitter, Chem. Ing. Tech. 91 (2019) 1302–1313.

[13] R. Ahmad, U. Arnold, D. Deutsch, M. Döring, J. Sauer, J. Mol. Catal. A Chem., 422 (2016) 207-215.

[14] D.M.E.F. Japan, DME handbook supplement, Japan DME Forum, Tokyo, 2011.

[15] E. Catizzone , M. Migliori, A. Aloise, R. Lamberti, G. Giordano,
Methods that will be used:
Inorganic Synthesis (hydrothermal treatment, surface modification, material characterization techniques), operation of lab-reactor for continuous gas-phase methanol dehydration (biosyngas use, online and offline analyses, mass balance determination and kinetics)
Collaboration partners:
National Institute of Renewable Energies (Golden, U.S.), Clariant (GE), other research teams at KIT and IKFT
Expected candidate‘s qualification:
MSc Chemistry or Chemical Engineering;
Successful applicants should be enthusiastic about challenging scientific and technical issues. They have good professional qualifications, either in inorganic synthesis or technical catalysis. Ideally, both of the latter criteria should be met in the highly interdisciplinary environment of the IKFT. Good language, presentation and writing skills in English are required. The willingness to acquire basic knowledge in German is expected. We want candidates to have the ability to work independently and effectively as well as team-oriented on the basis of good communication. After an induction period, candidates should be able to independently compile all necessary reports, documentation and presentations within the framework of their doctoral project.
Conversion of biosyngas, energy-related catalysis, catalyst development, process optimization