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151. Life cycle and upscaling: general discussion

Author

Armstrong, Katy, primary, Bachmann, Marvin, additional, Bardow, André, additional, Cao, Xiangkun Elvis, additional, Cassiola, Flavia, additional, Cummings, Charles, additional, Dowson, George, additional, Kamali, Ali Reza, additional, Leitner, Walter, additional, Manyar, Haresh, additional, McCord, Stephen, additional, North, Michael, additional, Pant, Deepak, additional, Park, Ah-Hyung Alissa, additional, Pérez-Fortes, Mar, additional, Platt, Edward, additional, Poon, Jeffrey, additional, Ramírez, Andrea, additional, Sick, Volker, additional, Styring, Peter, additional, Tanzer, Samantha Eleanor, additional, Tanveer, Waqas, additional, Thomas, Ollie, additional, and Whiston, Keith, additional

Published
2021
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152. Emerging technologies: general discussion

Author

Bardow, Andre, primary, Bizzarri, Claudia, additional, Cao, Xiangkun Elvis, additional, Cowan, Alexander J., additional, Cummings, Charles, additional, Del Angel Hernandez, Veronica, additional, Doan, Huan, additional, Dowson, George, additional, Ghosh, Sourav, additional, Gil, Vanesa, additional, Gugujonovic, Katarina, additional, Kamali, Ali Reza, additional, König, Max, additional, Leitner, Walter, additional, Luo, Jisiwei, additional, Madhav, Dharmjeet, additional, Maneiro, Marcelino, additional, Manyar, Haresh, additional, McCord, Stephen, additional, Moore, Elaine, additional, North, Michael, additional, Pant, Deepak, additional, Perry, Samuel, additional, Poon, Jeffrey, additional, Rossi, Liane, additional, Ruiz Esquius, Jonathan, additional, Schreiber, Moritz, additional, Shozi, Mzamo, additional, Sick, Volker, additional, Styring, Peter, additional, Tanveer, Waqas, additional, Thomas, Ollie, additional, Whiston, Keith, additional, and Yu, Eileen, additional

Published
2021
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154. Thermal catalytic conversion: general discussion

Author

Armstrong, Katy, primary, Barbarino, Sergio, additional, Cao, Xiangkun Elvis, additional, Cassiola, Flavia, additional, Catlow, Richard A., additional, Claeys, Michael, additional, Conway, Matthew, additional, Cowan, Alexander J., additional, de Leeuw, Nora H., additional, Dowson, George R. M., additional, Fischer, Nico, additional, Ghaderian, Abolfazl, additional, Ghosh, Sourav, additional, Kamali, Ali Reza, additional, Khan, Shaihroz, additional, Kyrimis, Stylianos, additional, Lawes, Naomi, additional, Leitner, Walter, additional, Maneiro, Marcelino, additional, Manyar, Haresh, additional, Marquart, Wijnand, additional, McCord, Stephen, additional, Moore, Elaine, additional, North, Michael, additional, Olsbye, Unni, additional, Pant, Deepak, additional, Poon, Jeffrey, additional, Quesne, Matthew G., additional, Ranocchiari, Marco, additional, Rossi, Liane, additional, Ruiz Esquius, Jonathan, additional, Shozi, Mzamo, additional, Sick, Volker, additional, Styring, Peter, additional, Tan, Jeannie, additional, Tanzer, Samantha Eleanor, additional, Thomas, Ollie, additional, Whiston, Keith, additional, and Wolf, Moritz, additional

Published
2021
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155. Synthetic ferripyrophyllite: preparation, characterization and catalytic application

Author

Qiao, Yunxiang, primary, Theyssen, Nils, additional, Spliethoff, Bernd, additional, Folke, Jan, additional, Weidenthaler, Claudia, additional, Schmidt, Wolfgang, additional, Prieto, Gonzalo, additional, Ochoa-Hernández, Cristina, additional, Bill, Eckhard, additional, Ye, Shengfa, additional, Ruland, Holger, additional, Schüth, Ferdi, additional, and Leitner, Walter, additional

Published
2021
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159. Organometallic Synthesis of Bimetallic Cobalt‐Rhodium Nanoparticles in Supported Ionic Liquid Phases (CoxRh 100−x@SILP) as Catalysts for the Selective Hydrogenation of Multifunctional Aromatic Substrates

Author

Rengshausen, Simon, primary, Van Stappen, Casey, additional, Levin, Natalia, additional, Tricard, Simon, additional, Luska, Kylie L., additional, DeBeer, Serena, additional, Chaudret, Bruno, additional, Bordet, Alexis, additional, and Leitner, Walter, additional

Published
2020
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162. Factors Governing the Catalytic Insertion of CO2 into Arenes – A DFT Case Study for Pd and Pt Phosphane Sulfonamido Complexes.

Author

Hölscher, Markus, Kemper, Gregor, Jenthra, Sangeth, Bolm, Carsten, and Leitner, Walter

Subjects
CARBOXYLATION, COMPUTATIONAL chemistry, AROMATIC compounds, CARBON dioxide, PALLADIUM compounds
Abstract

The potential of Pd/Pt complexes for catalytic carboxylation of arenes with CO2 is investigated by means of computational chemistry. Recently we reported that the bis[(2‐methoxyphenyl)phosphino]‐benzenesulfonamido palladium complex 1 inserts CO2 reversibly in its Pd−C(aryl) bond generating carboxylato complex 2. In the present work we study how geometric and electronic factors of various ligands and substrates influence the overall activation barrier (energy span, ES) of a potential catalytic cycle for arene carboxylation comprising this elementary step. The tendency of the key intermediates to dimerize and thus deactivating the potential catalysts is examined as well as the role of the base, which inevitably is needed to stabilize the reaction product. We show that Pd and Pt complexes I(Pd)‐L16‐S1 and I(Pt)‐L16‐S1 do not dimerize, enable the computation of complete catalytic cycles, and show interestingly low ES values of 26.8 and 24.5 kcal/mol, respectively. [ABSTRACT FROM AUTHOR]

Published
2022
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163. Selective hydrodeoxygenation of acetophenone derivatives using a Fe25Ru75@SILP catalyst: a practical approach to the synthesis of alkyl phenols and anilines.

Author

Goclik, Lisa, Walschus, Henrik, Bordet, Alexis, and Leitner, Walter

Subjects
RUTHENIUM catalysts, ACETOPHENONE derivatives, PHENOLS, ANILINE, PHENOL, IRON
Abstract

A versatile synthetic pathway for the production of valuable alkyl phenols and anilines has been developed based on the selective hydrodeoxygenation of a wide range of hydroxy-, amino-, and nitro-acetophenone derivatives as readily available substrates. Bimetallic iron ruthenium nanoparticles immobilized on an imidazolium-based supported ionic liquid phase (Fe25Ru75@SILP) act as highly active and selective catalysts for the deoxygenation of the side-chain without hydrogenation of the aromatic ring. The catalytic system allows operation under continuous flow conditions with high robustness and flexibility as demonstrated for the alternating conversion of 3′,5′-dimethoxy-4′-hydroxyacetophenone and 4′-hydroxynonanophenone as model substrates. [ABSTRACT FROM AUTHOR]

Published
2022
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165. Operando monitoring of mechanisms and deactivation of molecular catalysts.

Author

Köhnke, Katrin, Wessel, Niklas, Esteban, Jesús, Jin, Jing, Vorholt, Andreas J., and Leitner, Walter

Subjects
CATALYSTS, TRANSITION metal catalysts, HOMOGENEOUS catalysis, CHEMICAL reactions, CATALYST poisoning, CHEMICAL species, ORGANIC conductors
Abstract

Observing and understanding the phenomena associated with the reaction mechanisms and catalyst deactivation in molecular catalysis is a very challenging task in green chemistry. This knowledge is crucial for applying and scaling catalyzed reactions as well as preventing misproduction at a very early point. Over the years, experimental arrangements have evolved towards analysis of catalysts and reaction products in the so-called operando setups. This contribution reflects on the potential of operando studies to elucidate reaction and deactivation mechanisms in homogeneous catalysis as well as the outstanding opportunities that arise from the application of operando experimental setups. Such setups mostly rely on spectroscopic analysis, optionally coupled with chromatographic techniques that monitor the reaction system. This in turn means that not only the evolution of the reaction substrates and products can be monitored, but also changes of the molecular catalyst species that may affect the catalytic performance. Therefore, this review focusses on techniques to monitor the catalyst under real conditions. In this review, different spectroscopic techniques relevant for monitoring molecular transition metal catalysts in solution are covered, followed by numerical methods used in the chemometrics literature to undertake the challenge of untangling the complex raw signals and allocating them to individual chemical species. Finally, two exemplary case studies of industrially relevant chemical reactions are presented, namely the hydroformylation and the asymmetric hydrogenation. These examples illustrate the significance of the application of both the experimental setups as well as data processing and signal resolution to have an insight into the deactivation of catalytic systems. The operando approach shows high potential for the increased use in future research to develop stable and more selective catalysts which can be applied in greener processes. [ABSTRACT FROM AUTHOR]

Published
2022
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167. Supercritical carbon dioxide as a green reaction medium for catalysis

Author

Leitner, Walter

Subjects
Green products -- Research, Catalysis -- Methods, Carbon dioxide -- Usage, Supercritical fluid extraction -- Methods, Chemistry, Science and technology
Abstract

The impact of supercritical carbon dioxide on green organometallic catalytic systems is discussed with reference to its environmentally safe reaction medium for the syntheses of chemical compounds. It is a chosen substitute for potentially hazardous solvents and has application in catalytic synthetic methodologies.

Published
2002

168. The photophysics of 6-(1-pyrenyl)hexyl-11(1-pyrenyl)undecanoate dissolved in organic liquids and supercritical carbon dioxide: impact on olefin metathesis

Author

Pandey, Siddharth, Kane, Maureen A., Baker, Gary A., Bright, Frank V., Furstner, Alois, Seidel, Gunter, and Leitner, Walter

Subjects
Chemistry, Physical and theoretical -- Research, Liquids -- Physiological aspects, Carbon dioxide -- Physiological aspects, Olefins -- Physiological aspects, Chemicals, plastics and rubber industries
Published
2002

172. Introduction

Author

Cornils, Boy, primary, Herrmann, Wolfgang A., additional, Horváth, István T., additional, Leitner, Walter, additional, Mecking, Stefan, additional, Olivier-Bourbigou, Hélène, additional, and Vogt, Dieter, additional

Published
2008
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174. Olefin metathesis in supercritical carbon dioxide

Author

Furstner, Alois, Ackermann, Lutz, Beck, Karsten, Hori, Hisao, Koch, Daniel, Langemann, Klaus, LIebl, Monika, Six, Christian, and Leitner, Walter

Subjects
Carbon dioxide -- Research, Ring formation (Chemistry) -- Observations, Supercritical fluid extraction -- Research, Chemistry
Abstract

Ring closing olefin metathesis reactions in supercritical carbon dioxide were studied.

Published
2001

175. Synthesis and structural features of complexes [[([P.sup.[intersection]]P).sub.2]Rh][hfacac] containing hexafluoroacetyl-acetonate as a noncoordinating anion

Author

Fornika, Roland, Six, Christian, Gorls, Helmar, Kessler, Magnus, Kruger, Carl, and Leitner, Walter

Subjects
Organic compounds -- Synthesis, Coordination compounds -- Analysis, Complex compounds -- Analysis, Rhodium, Chelating agents -- Analysis, Ligands -- Analysis
Abstract

The synthesis and characterization of complexes [[(P.sup.[intersection]]P).sub.2]Rh][hfacac] (P[intersection]]P = chelating bidentate phosphine ligand [R.sub.2]P[(C[H.sub.2]).sub.n] P[R.sub.2] (2a-g), hfacac = hexafluoroacetylacetonate anion) (4) is reported. The molecular structures of 4a (R = Ph, n = 1) and 4f (R = Cy, n = 2) in the solid state were determined by single-crystal X-ray diffraction. The complexes crystallize in the monoclinic space groups C2/c (No. 15) and P[2.sub.1]/n (No. 14), respectively. No coordinative interaction between the rhodium center of the cation [[(P.sup.[intersection]]P).sub.2])Rh].sup.+] (4[a.sup.+], 4[f.sup.+]) and the hfacac anion is evident in either cases. In the crystal structure of 4a, hydrogen bonds between the oxygen atoms of the hfacac anion and methylene protons of the C[H.sub.2] bridges of the phosphine ligand lead to highly symmetric chains of regularly alternating cations and anions. The coordination geometry around the rhodium center in 4[a.sup.+] is ideally square-planar, whereas 4[f.sup.+] is significantly distorted towards a tetrahedron with an angle between the two [P.sub.2]Rh moieties of 18.6[degrees]. The cation 4[b.sup.+] (R = Cy, n = 1) was investigated in form of the tetrafluoroborate salt for comparison. The compound [[{[Cy.sub.]P(C[H.sub.2])P[Cy.sub.]}.sub.2]Rh] [B[F.sub.4]] crystallizes as a THF solvate (4b') in the triclinic space group P [bar]1 (No. 2) containing ideally square-planar [[(P.sup.[intersection]]P).sub.2])Rh].sup.+] cations. Key words: rhodium, chelating ligands, coordination modes, 1,3-diketonates, phosphorus ligands.

Published
2001

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