Andrea Schmidt

Bio: Andrea Schmidt is an academic researcher from Technical University of Berlin. The author has contributed to research in topics: Catalysis & Membrane. The author has an hindex of 7, co-authored 8 publications receiving 247 citations.

Catalytic Membrane Reactors for Partial Oxidation Using Perovskite Hollow Fiber Membranes and for Partial Hydrogenation Using a Catalytic Membrane Contactor

Abstract: Two consecutive model reactions of the type A - B→ C are studied in two kinds of catalytic membrane reactors. The partial oxidation of methane to synthesis gas due to CH 4 + 1/ 2 0 2 → CO + 2H 2 was investigated in a novel type of permselective membrane reactor using perovskite hollow fibers for the selective separation of oxygen from air. Partial hydrogenations were studied in a pore-through-flow membrane reactor as a special type of a catalytic membrane contactor. The catalytically functionalized pores of the membrane provide a medium with defined contact times for the cofeed of hydrogen and an unsaturated hydrocarbon, and the attempts of the scale-up of the successful laboratory experiments to the pilot scale are reported.

Partial hydrogenation of sunflower oil in a membrane reactor

Abstract: Partial hydrogenation of sunflower oil was carried out in a membrane reactor in pore-flow-through mode in n-heptane as solvent. The membrane reactor consisted of a porous α-Al2O3 membrane impregnated with Pd or Pt as the active catalyst and was constructed as a loop of saturation vessel and membrane module. Hydrogenation experiments were performed at different temperatures, hydrogen pressures and noble metals as catalysts. The experiments in the membrane reactor were compared with experiments in a slurry reactor with a powder catalyst for benchmarking. The stearic acid content at an iodine value (IV) of about 80 was 10–15% in the membrane reactor and 45% in the slurry reactor, respectively. The selectivity for the monoene fatty acids could be improved with decreasing hydrogen pressures. The content of trans fatty acids at IV ≈ 80 was 30–45% in the membrane reactor, whereas in the slurry reactor 12% were obtained. For the trans-isomer formation, the influence of hydrogen pressure and temperature in the membrane reactor was rather low. Pd showed a higher activity and selectivity compared to Pt, but promoted the trans-isomerization to a greater extent.

Kinetics of 1,5-cyclooctadiene hydrogenation on Pd/α-Al2O3

Abstract: The intrinsic kinetics of the hydrogenation reaction of 1,5-cyclooctadiene (COD) to cyclooctene (COE) and of COE to cyclooctane (COA) was investigated in a wide range of reaction conditions: 40-70 °C, 0.2-1 MPa hydrogen pressure, and an initial COD concentration of 0.41-0.82 mol/L with a fine powder (100μm grain size) of a Pd/α-Al 2 O 3 catalyst in a slurry reactor. Reaction rates were found to depend on COD, COE, and hydrogen concentrations according to a Langmuir-Hinshelwood-type rate law. Rate constants and activation energies were determined by fitting the kinetic model to experimental data. Activation energies of 74 kJ/mol for the reaction of COD to COE and of 98 kJ/mol for the reaction of COE to COA were determined.

α‐methylstyrene hydrogenation in a flow‐through membrane reactor

Abstract: The hydrogenation of α-methylstyrene (AMS) was carried out in a flow-through membrane reactor at: 45-50°C, 1-40 bar, and 18 vol % AMS in heptane. An α-Al 2 O 3 membrane tube of defined pore size was used as catalyst support material. A wet impregnation method was used to prepare the active membrane with palladium as catalyst. Experiments with a spherical Pd/Al 2 O 3 egg-shell catalyst in a slurry reactor were carried out under similar reaction conditions for comparison. Results from the flow-through membrane reactor were also compared to results from other types of reactors described in the literature. Application of the flow-through membrane reactor exhibits an enhanced performance with respect to the productivity (reaction rate per mass of palladium) relative to that of other types of membrane reactors and other conventional reactors, such as a slurry reactor, a trickle-bed reactor, and a bubble-column reactor.

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

Abstract: Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. Heterogeneous catalytic hydrogenation reactions under continuous flow conditions offer significant benefits compared to batch processes which are related to the unique gas-liquid-solid triphasic reaction conditions present in these transformations. In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized. Available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale flow hydrogenation reactions are presented.

Simultaneous Production of Hydrogen and Synthesis Gas by Combining Water Splitting with Partial Oxidation of Methane in a Hollow‐Fiber Membrane Reactor

Abstract: Hydrogen is gaining more and more attention because it is regarded as an important future fuel. Today, hydrogen is mainly produced from nonrenewable natural gas and petroleum. With concerns over worldwide energy demands and global climate change, alternative sources must be found. Obviously, water is recommended as the ideal source for the generation of large amounts of hydrogen. In addition to electrolysis, recently several new processes, such as photovoltaic–photoelectrochemical water splitting and one-step or multistep thermochemical water splitting 6] based on focused solar or nuclear heat, have been developed. Although water dissociation into oxygen and hydrogen is conceptually simple [Eq. (1)], efficient hydrogen production

Solid Catalyst with Ionic Liquid Layer (SCILL) – A New Concept to Improve Selectivity Illustrated by Hydrogenation of Cyclooctadiene

Abstract: A new concept of a solid catalyst with ionic liquid layer (SCILL) as a novel method to improve the selectivity of heterogeneous catalysts is presented. The sequential hydrogenation of cyclooctadiene (COD) to cyclooctene (COE) and cyclooctane on a commercial Ni catalyst coated with the ionic liquid [BMIM][n-C8H17OSO3] was tested as first model system. Compared to the original catalyst, the coating of the internal surface with the ionic liquid (IL) strongly enhances the maximum intrinsic COE yield from 40 to 70 %. This effect is already achieved for a pore filling degree of only 10 % and cannot be explained by pore diffusion, as shown by experiments with different particle sizes and theoretical considerations. The IL layer is very robust and no leaching into the organic phase was detectable.

Palladium membranes applications in reaction systems for hydrogen separation and purification: A review

Abstract: Application of palladium-based membrane technology in chemical reactions is currently focused on producing ultrapure hydrogen. Due to the environmental concerns and undesirable side effects of greenhouse gases, hydrogen has great potential as an alternative future fuel. Pd-alloy membranes have demonstrated tremendous potential for the hydrogen extraction in hydrogen-dependent reactions. Numerous studies have been done investigating the diffusion of hydrogen through palladium membranes. In this review, the ability of Pd-alloy membrane reactors in the removal of hydrogen from water gas shift, steam reforming, and dehydrogenation reactions is evaluated. This review is divided into several sections including palladium membranes, Pd-alloy membranes, composite Pd-based membranes, and their preparation methods Moreover, the hydrogen permeation rate, Sieverts’ law, Damkohler-Peclet product design parameter, and various membrane reactors will be discussed in detail. There is also an overview of the last-decade researches on Pd-based membrane reactors. Finally, some essential ideas for the improvement of future membrane technology are proposed.