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In order to increase the typically low equilibrium CO2 conversion to methanol using commercially proven technology, the addition of two intermediate condensation units between reaction steps is evaluated in this work. Detailed process simulations with heat integration and techno-economic analyses of methanol synthesis from green H2 and captured CO2 are presented here, comparing the proposed process with condensation steps with the conventional approach. In the new process, a CO2 single-pass conversion of 53.9% was achieved, which is significantly higher than the conversion of the conventional process (28.5%) and its equilibrium conversion (30.4%). Consequently, the total recycle stream flow was halved, which reduced reactant losses in the purge stream and the compression work of the recycle streams, lowering operating costs by 4.8% (61.2 M€·a−1). In spite of the additional number of heat exchangers and flash drums related to the intermediate condensation units, the fixed investment costs of the improved process decreased by 22.7% (94.5 M€). This was a consequence of the increased reaction rates and lower recycle flows, reducing the required size of the main equipment. Therefore, intermediate condensation steps are beneficial for methanol synthesis from H2/CO2, significantly boosting CO2 single-pass conversion, which consequently reduces both the investment and operating costs.

Das Institut fur Heise Chemie IHCh wurde 1959 gegrundet, um die Entwicklung der Technologie zur Wiederaufarbeitung von Kernbrennstoffen zu unterstutzen. Aufbauend auf dem sog. PUREX-Prozess wurden mogliche Varianten zur Abtrennung von noch nutzbarem Spaltmaterial durch Kombination verschiedenster Extraktions- und Redoxverfahren vom Labor- bis zum Pilotmasstab entwickelt, bis dieser mit nur noch einem Extraktionszyklus auskam. Mit dem Ende der nuklearen Reaktorforschung wurden als Institut fur Technische Chemie neue Themen aus der Umwelt- und Energieforschung aufgegriffen. In dieser Zeit wurde im Rahmen der internationalen Kollaboration GALLEX ein radiochemischer Sonnenneutrino-Detektor gebaut und erfolgreich betrieben.

Correction for ‘Surface reaction kinetics of the methanol synthesis and the water gas shift reaction on Cu/ZnO/Al2O3’ by Bruno Lacerda de Oliveira Campos et al., React. Chem. Eng., 2021, 6, 868–887; DOI: 10.1039/D1RE00040C

A three-site mean-field extended microkinetic model was developed based on ab initio DFT calculations from the literature, in order to simulate the conversion of syngas (H2/CO/CO2) to methanol on Cu (211) and Cu/Zn (211). The reaction network consists of 25 reversible reactions, including CO and CO2 hydrogenation to methanol and the water-gas shift reaction. Catalyst structural changes are also considered in the model. Experiments were performed in a plug flow reactor on Cu/ZnO/Al2O3 at various gas hourly space velocities (24–40 L h−1 gcat−1), temperatures (210–260 °C), pressures (40–60 bar), hydrogen feed concentrations (35–60% v/v), CO feed concentrations (3–30% v/v), and CO2 feed concentrations (0–20% v/v). These experiments, together with experimental data from the literature, were used for a broad validation of the model (a total of 690 points), which adequately reproduced the measurements. A degree of rate control analysis showed that the hydrogenation of formic acid is the major rate controlling step, and formate is the most sensitive surface species. The developed model contributes to the understanding of the reaction kinetics, and should be applicable for industrial processes (e.g. scale-up and optimization).

Hybrid kinetic models represent a promising alternative to describe and evaluate the effect of multiple variables in the performance of complex chemical processes, since they combine system knowledge and extrapolability of the (semi-)mechanistic models in a wide range of reaction conditions with the adaptability and fast convergence of data-based approaches (e.g., artificial neural networks—ANNs). For the first time, a hybrid kinetic model for the direct DME synthesis was developed consisting of a reactor model, i.e., balance equations, and an ANN for the reaction kinetics. The accuracy, computational time, interpolation and extrapolation ability of the new hybrid model were compared to those of a lumped and a data-based model with the same validity range, using both simulations and experiments. The convergence of parameter estimation and simulations with the hybrid model is much faster than with the lumped model, and the predictions show a greater degree of accuracy within the models’ validity range. A satisfactory dimension and range extrapolation was reached when the extrapolated variable was included in the knowledge module of the model. This feature is particularly dependent on the network architecture and phenomena covered by the underlying model, and less on the experimental conditions evaluated during model development.

Kinetic investigations and model-based optimization of CuO/ZnO/ZrO2 : H-FER 20 catalytic systems for direct DME synthesis from CO2-rich syngas.

A microfluidic reactor enabled continuous co-precipitation synthesis of CuO/ZnO/Al2O3 catalysts for methanol production.

PtX technologies are one major building block of the future energy system based on renewables sources. Dimethyl ether (DME) is an important PtX product that can be used as intermediate the production of CO$_{2}$-neutral base chemicals. New applications lead to an increase of the global production and the optimization of the process efficiency, especially when considering decentralized synthesis. This review article puts some spotlights on recent developments in methanol and the direct DME synthesis with a special focus on the modeling and bifunctional catalyst. This study is expected to provide a foundation for future works in the field of catalysis research based on catalysts design and kinetic modeling.

Zirconia-modified copper catalysts are being actively discussed to be beneficial in CO2/H2 conversion to methanol. The nature of the promotional effect of ZrO2 is still an intense matter of debate....

The one-step synthesis of dimethyl ether over mechanical mixtures of Cu/ZnO/Al

Catalyst systems for the conversion of synthesis gas, which are tolerant to fluctuating CO/CO

Hierarchical H-ZSM-5 zeolites are a promising class of heterogeneous catalysts that have shown encouraging results in lab-scale studies for the production of gasoline from dimethyl ether (DTG conversion). However, the influences of mesopore formation and shaping on various catalyst properties are still under debate. In this study, a series of H-ZSM-5 zeolites with hierarchical pore structures were prepared by modifying commercially available zeolites via alkaline treatment ("desilication"). The powdered zeolites were shaped into technical catalyst bodies by wet extrusion using either silica or alumina binders. All materials were extensively characterized. The different interactions during alkaline treatment were related to the observed modifications in the zeolite properties of the materials obtained. Although many properties of modified and untreated zeolite powders remained predominantly unchanged in their shaped catalyst equivalents, both binders affected certain material characteristics, particularly those related to their acidity. Finally, preliminary tests showed enhanced catalytic performance of hierarchical ZSM-5 catalysts in DTG conversion.

Within the so-called bioliq® process, renewable carbon resources, especially agricultural residues, are converted to gasoline. The process chain comprises pyrolysis of the feedstocks, gasification to synthesis gas, gas cleaning and conversion of synthesis gas to dimethyl ether (DME) followed by conversion of DME to hydrocarbons. Construction of all process units has been completed now and the entire plant has been successfully operated in several campaigns. Thus, hundreds of liters of a new alternative gasoline are available now, which allow for an extensive testing. The basic characteristics of the resulting bioliq®/100 fuel are described. It is rich in aromatics and a blend consisting of 90 Vol.−% of conventional RON95 E5 fuel and 10 Vol.−% of bioliq®/100, designated as bioliq®/10, has been produced which meets the DIN EN 228 standard. Initial measurements on a single cylinder research engine have been carried out focusing on efficiency and emissions. A comparison of bioliq®/10 with neat RON95 E5 revealed an improved knocking behavior of bioliq®/10 even by a small fraction of regenerative bioliq® fuel. Particle as well as hydrocarbon emissions from bioliq®/10 are significantly higher than in the case of RON95 E5. Increased particle emissions are attributed to the higher content of aromatics. Soot reactivity has been investigated and soot from bioliq®/10 exhibits higher reactivity than soot from RON95 E5.

The potential of hierarchical H‐ZSM‐5 zeolites was studied for the conversion of DME to fuel‐compatible hydrocarbons. For this purpose, hierarchical H‐ZSM‐5 zeolites have been prepared from commercial H‐ZSM‐5 by desilication and organosilane‐directed hydrothermal synthesis. The zeolites were characterized by X‐ray diffraction, NH3‐TPD, DRIFTS, and N2 physisorption measurements. The catalysts have been tested in a tube reactor (1 bar, 648 K). The results indicate important structural changes in framework and acidic sites, which are significant for the synthesis of gasoline‐range hydrocarbons.

High-pressure in situ IR and NMR investigations of the hydromethoxycarbonylation of 1,3-butadiene (1) to methyl 3-pentenoate (2) in methanol in the presence of Co2(CO)8 and pyridine under carbon monoxide has revealed that the reaction starts by the methanol- and/or pyridine-assisted disproportionation of Co2(CO)8, followed by the establishment of equilibria involving the ionic species [Co(Py)6]2+{[Co(CO)4]−}2, [Co(Py)6]2+[MeO]−[Co(CO)4]−, [PyH]+[Co(CO)4]−, and [MeOH2]+[Co(CO)4]−. The addition of HCo(CO)4 (3) to pyridine or methanol results in the formation of [PyH]+[Co(CO)4]− and [MeOH2]+[Co(CO)4]−, respectively, and 3 is not detectable by either IR or NMR. The ionic 1,4-addition of [MeOH2]+[Co(CO)4]− to 1 is the only pathway to 2-butenylcobalt tetracarbonyl, CH3CH═CHCH2Co(CO)4 (4), via the protonation of 1 followed by the reaction of the C4 carbocation with the counteranion tetracarbonylcobaltate. In the absence of carbon monoxide, 4 could lose a coordinated carbon monoxide to form (η3-C4H7)Co(CO)3 (7) i...

Diese Arbeit untersucht die Machbarkeit der Ag-katalysierten Epoxidierung von 1,3-Butadien (1,3-BD) zu 3,4-Epoxy-1-buten (EpB) in einem am Forschungszentrum Karlsruhe entwickelten Mikroreaktor (MR) [1]. Fur Vorversuche kommt ein Rohrreaktor (RR) zum Einsatz. Als Katalysator wird ein α-Al2O3-Trager eingesetzt, auf dem die Aktivkomponenten aufgebracht sind. Die Epoxidierung erfolgt im Bereich von 180 °C bis 320 °C und Raumgeschwindigkeiten (RG) von 2950 h–1 bis 17 701 h–1 bei Umgebungsdruck in einem Katalysatorteststand. Die hochste EpB-Selektivitat von 52 % wird bei einem 1,3-BD-Umsatz von 2,1 % und einer RG von 8851 h–1 mit mikrostrukturierten Ti-Folien bei 240 °C erreicht.

The title compound (1) was prepared by the reaction of 3,5-bis(CF3)C6H3P(i-C3H7)2 (L1) and Co2(CO)8. Its solubility in supercritical carbon dioxide was measured at varying temperatures and pressures using a modified analytical extraction device. Solubility data were determined in the temperature and pressure ranges between 40 and 70 °C and between 100 and 300 bar, respectively. The solubility of 1 is lower compared to (p-CF3C6H4)3P, but much higher than for transition metal complexes bearing phosphines without fluorinated substituents.

The homogeneously catalyzed hydroformylation of linear olefins was investigated at pressures ranging from 7 to 550 MPa. A change in the selectivity was observed, which was reflected by a change of the product distribution. At high-pressures, increased yields of aldehydes were also obtained from the hydroformylation of sterically hindered olefins.

The ruthenium-catalysed hydrosilylation of CO2 was studied with respect to the influences of the solvent present and different co-ligands used. Nitriles exhibit favourable properties as a solvent for this reaction. The catalytic activity of [RuCl(MeCN)5]+[(trans)-RuCl4(MeCN)2]− as pre-catalyst may be increased by additional phosphine ligand. Further N-donor substituents in the phosphine do not result in an increased activity. The homogeneous catalyst may be recycled effectively by a thermal separation of the reaction product. For this procedure, the catalytic activity kept constant during 10 runs.

Carbon dioxide was used not only as a reaction medium but also as a renewable C1 feedstock for the palladium catalyzed coupling reaction of butadiene and carbon dioxide. By utilization of nitrile modified phosphine ligands, in the liquid phase complete butadiene conversion and selectivity for the formation of (3E)-3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one (1) up to 47% were achieved. Phase equilibrium considerations were used for process development in order to realize single-phase conditions for the reaction. In contrast to a CO2 enriched phase composition, variation of the density only enables moderate conversion rates also with single-phase conditions and without further catalyst modification.

Recent results on the heterogeneously catalyzed co-oligomerization of 1,3-butadiene and carbon dioxide are presented. Optimized preparation methods for the reaction of Pd(η3-C3H5)(η5-C5H5) 2 with [(i-Pr)2P–CH2]-polystyrene derivative PS-P yield palladium catalysts immobilized on polystyrene support (PS-01, PS-02, PS-03). Consequently, `leaching' is reduced and catalysts may be re-used several times after a simple separation and cleaning procedure. Additionally, a similar immobilization of palladium complex units on silica is reported. The correlation of the formation of 2-[(E)-ethylidene]-6-heptene-5-olide 1 with process parameters such as temperature, kind of catalyst, and solvent, is presented and discussed in detail. Analytical methods (CP-MAS-NMR, XPS, SEM) were used to determine PS-02 before and after use. XPS data indicate an initial Pd0 oxidation state. Used PS-02 possesses a changed coordination sphere around the anchored palladium centres which agrees to its different catalytic behaviour.

A series of P,N ligands of the general formula (2-py)-(CH2) n -PR 2 (2-py: 2-pyridyl; R: i-Pr (n=1, 4–7), Ph (n=5–7)) 4a–g and 6a has been synthesized. Starting from 2-picoline (1), 2-(ω-chloroalkyl)pyridines 3a–d are prepared. The reactions of 3a–d with (i-Pr)2PLi and Ph2PLi, respectively, result in the title compounds 4a–g in up to 89% yield. Reaction of Cl-(CH2)3-P(i-Pr)2 with 2-picolyllithium (2) is an alternative route to 4a. Additionally, P,P,N ligands 7a and 9 are synthesized by similar methods. All new compounds were fully characterized. The formation of cyclic pyridinium derivatives 5a and 5b from intramolecular S N reactions of 3a and 3b is discussed in detail.

By means of photoinitiated SH-En-polyaddition of 2-ethylidene-6-hepten-5-olide (6-lactone) and 2,2'-(ethylenedioxy)diethanethiol or 1,3 -bis(3-mercaplopiopyl)-1,1,3,3-tetramethyldisiloxane, it was possible for the first time to form a high-molecular linear polymer with an intact lactone structure. Under these conditions, the reactivity does not depend on the carbon-carbon double bond structure. With pentaerythritoltetrakis(3-mercaptopropionate) as a crosslinking agent, networks are formed; the structure of the comonomers and the proportionate composition of the monomers modify the polymer properties. These novel polymers have been fully characterized.

‘In situ’ catalysts prepared from (η5-C5H5)Pd(η3-C3H5) 9 and phosphinoalkyl nitriles 10a–e of the general formula (iC3H7)2P(CH2)nCN have been used to catalyse the co-oligomerisation of 1,3-butadiene and carbon dioxide. The δ-lactone 2-ethylidene-6-heptene-5-olid 1 is formed, yielding up to 74%. Different solvent systems have been used of which pyridine provides the best result. The catalysis may also be performed without additional solvent. A minimum of five CH2 units (n = 5) within the ligand is necessary to produce 1 with a selectivity higher than 29% in a solvent-free reaction. Therefore, phosphinoalkyl nitriles of the type described here are acting as hemilabile ligands in the catalytic cycle.

Immobilized catalysts prepared from [Pd(η 5 -C 5 H 5 )(η 3 -C 3 H 5 )] ( 5 ) and polymer bound phosphines 4a–c are used to catalyse C,C coupling reactions of carbon dioxide and any organic co-substrate for the first time in a heterogeneous way. These phosphines, synthesised from chloromethylated polystyrene, are characterised by their elemental analysis data and NMR spectra. The immobilized catalyst from polymer 4a and 5 catalyses the formation of the δ-lactone 2-ethylidene-6-heptene-5-olid ( 1 ). With low reaction rates, up to 72% selectivity to 1 is observed, These catalysts can be used in multiple reactions. In an analogous procedure using polymer 4b , the synthesis of C 17 carboxylic esters is successful.

Phosphinoalkylnitriles R2P-(CH2)n-CN {R = isopropyl (ipr), phenyl (ph), cyclohexyl (chex), n = 3, 6, 10} have been prepared starting from the corresponding secondary phosphines in an easy three step synthesis. All new compounds were characterized by their 1H -, 13C and 31P NMR data. Some of these new P, N ligands were used to prepare complexes [{R2P- (CH2)n-CN}2PdCl2] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{ipr2P-(CH2)3-CN}2PdCl2] 7a, [{ph2P-(CH2)3-CN}2PdCl2) 7b and [{ph2P-(CH2)6-CN}2PdCl2] 8b were determined by X-ray analysis. The coordination mode of the phosphinoalkylnitriles in these complexes was found to be P-bonded resulting in a trans configuration. Palladium catalysts with 5a as ligand show high activies in the co-oligomerization of butadiene and carbon dioxide. The δ-lactone 11a is formed under very mild conditions.

A series of P,N ligands of the general formula (2-py)-(CH2) n -PR 2 (2-py: 2-pyridyl; R: i-Pr (n=1, 4–7), Ph (n=5–7)) 4a–g and 6a has been synthesized. Starting from 2-picoline (1), 2-(ω-chloroalkyl)pyridines 3a–d are prepared. The reactions of 3a–d with (i-Pr)2PLi and Ph2PLi, respectively, result in the title compounds 4a–g in up to 89% yield. Reaction of Cl-(CH2)3-P(i-Pr)2 with 2-picolyllithium (2) is an alternative route to 4a. Additionally, P,P,N ligands 7a and 9 are synthesized by similar methods. All new compounds were fully characterized. The formation of cyclic pyridinium derivatives 5a and 5b from intramolecular S N reactions of 3a and 3b is discussed in detail.

Ruthenium complexes, mer-[RuX(3)(MeCN)(3)] and cis/trans-[RuX(2)(MeCN)(4)] with X=Br, Cl, were investigated as precatalysts in homogeneously catalyzed hydrosilylation of CO(2). The oxidation state of ruthenium and nature of the halide in the precatalysts were found to influence the catalytic activity in the conversion of Me(2)PhSiH to the formoxysilane Me(2)PhSiOCHO, with Ru(III) having chloride ligands being most active. Monitoring the reactions by in-situ IR spectroscopy in MeCN as the solvent indicates an interaction of the precatalyst with the silane prior to activation of CO(2). In the absence of CO(2), hydrosilylation of the MeCN solvent occurs. Catalytic activity in CO(2) hydrosilylation is enhanced by Me(2)PhSiCl, generated during reduction of Ru(III) in mer-[RuX(3)(MeCN)(3)] to Ru(II) or, when added as promoter to Ru(II) precatalysts. The reaction mechanism for the catalytic cycle has been calculated by DFT methods for the reaction of Me(3)SiH. The key steps are: Transfer of the Me(3)Si moiety to a coordinated halide ligand, resulting in an L(n)RuH(XSiMe(3)) intermediate --> CO(2) coordination --> Me(3)Si transfer to CO(2) --> reductive elimination of formoxysilane product. This reaction sequence is more favorable energetically for chloride complexes than for the analogous bromide complexes, which accounts for their differences in catalytic activity. Calculations also explain the rate increase observed experimentally in the presence of Me(2)PhSiCl. A parallel reaction pathway leads to (Me(3)Si)(2)O as a minor byproduct which arises from the condensation of two initially formed Me(3)SiOH molecules.

The present contribution highlights the relationship between scCO 2properties, its solubilization power, and its use as a reaction medium for homogeneous catalysis.Current research activities under the lighthouse project “Smart Solvents, Smart Ligands”are presented, the focus being on criteria of conducting catalyzed processes in future applications.

The oxidative amination of styrene with secondary amines in the presence of cationic rhodium catalysts yields regiospecifically the corresponding anti-Markovnikov enamines. Styrene as the hydrogen acceptor gave concomitantly ethylbenzene. In the presence of 1,5-cyclooctadiene (cod) preferential reduction to cyclooctene takes place. The addition of cod reduces the rate of the reaction, but also the amount of ethylbenzene produced. Here, for the first time the ratio of enamine: ethylbenzene is > 1, which is favourable in case of more expensive styrene derivatives. A screening of various ligands for oxidative amination reveals that hemilabile 2-(ω-phosphino-n-alkyl)-pyridines are superior ligands for this reaction compared to simple alkyl and aryl phosphines.