Device and method for carrying out a chemical reaction

Abstract

The present invention relates to a device (1) for carrying out a chemical reaction, in particular a thermally catalyzed reaction, comprising a reaction chamber (2) in which the chemical reaction can take place, a catalyst medium (3), and at least one voltage source (4) which interacts or can interact with the catalyst medium (3) in such a way that an electrical potential can be applied to the catalyst medium (3) in order to influence the course of the chemical reaction.

Description

[0001] DESCRIPTION

[0002] Apparatus and method for carrying out a chemical reaction

[0003] The present invention relates to a device for carrying out a chemical reaction, in particular a thermally catalyzed reaction. The invention further relates to a method for carrying out such a reaction.

[0004] Thermally catalyzed or thermocatalytic reactions, which take place in a liquid phase or in a mixed phase containing liquid and gaseous components, are widely used. Typically, the course of such reactions is controlled by the properties of the chosen catalyst medium. This allows for the optimization of activity, reaction rate, conversion, yield, selectivity, stability, and turnover number. For example, the catalyst medium can be tailored to the reaction. This can be achieved, for instance, through surface modification, by selecting a specific particle size, or by maintaining a specific temperature profile within the apparatus. The alloy of the catalyst medium can also influence the reaction process.

[0005] The properties of the catalyst, and thus the reaction conditions, can only be changed discretely through external modifications. Once a catalyst medium has been introduced into a device, it can no longer be changed or adapted to the reaction conditions. Furthermore, aging effects cannot be compensated for, or only poorly.

[0006] Against this background, the object of the present invention is to provide an alternative device and an alternative method which in particular enables a simple and flexible adaptation of the reaction process.

[0007] This problem is solved in a device of the type mentioned above by providing a reaction chamber in which the chemical reaction can take place, a catalyst medium, and at least one voltage source which interacts or can interact with the catalyst medium in such a way that the catalyst medium can be subjected to an electrical potential to influence the course of the chemical reaction. Preferably, the reactants and / or products are in a liquid state or in a mixed state of a gaseous and liquid state. The catalyst medium is preferably designed as a solid or as a homogeneous catalyst in an immobilizing phase.

[0008] Furthermore, the problem underlying the invention is solved by a method for carrying out a chemical reaction, in particular a thermally catalyzed reaction, wherein reactants and / or products are preferably in a liquid state or in a mixed state of a gaseous and liquid state, using such a device, wherein the catalyst medium is subjected to an electrical potential in order to influence the reaction process.

[0009] The invention is based on the fundamental idea of ​​improving the effect of the catalyst medium by applying an electric field to the catalyst surface. This allows the structure of the solid-liquid interface or the solid-liquid-gas interface, particularly between the catalyst medium and a reaction medium or the reactants and / or products of the chemical reaction, to be controlled in a targeted and continuous manner. In particular, adjustments can also be made during the reaction process. In other words, the physical and electronic structure of the catalyst medium, and consequently also of the reactants, can be adapted. The reaction can thus be electrochemically controlled.

[0010] Preferably, the potential applied to the catalyst medium is continuously controlled to achieve a desired activity, reaction rate, conversion, yield, selectivity, stability, and / or turnover number. Such a solution is also cost-effective and easy to implement, as no external modifications to the catalyst medium are required.

[0011] In a specific embodiment, the chemical reaction can be or include hydrogenation, dehydrogenation, reforming, oxidation, deoxygenation, coupling, cleavage, and / or functionalization. The device can therefore be used for hydrogenation, dehydrogenation, reforming, oxidation, deoxygenation, coupling, cleavage, and / or functionalization.

[0012] In a specific embodiment, the device can be configured as a reactor, in particular as a flow-tube reactor or a stirred-tank reactor. The device can also be configured as a tube bundle reactor. In a further embodiment, the device can include a counter electrode. This embodiment is based on the idea of ​​generating an electric field between the catalyst medium, which is subjected to a potential, and the counter electrode. This allows the structure of the interface between the catalyst medium and a liquid or a mixture of a liquid and a gas to be controlled in a targeted and continuous manner.

[0013] The counter electrode can be connected to at least one voltage source. This allows the counter electrode to be subjected to an electrical potential. In this case, a voltage can be applied between the counter electrode and the catalyst medium. The device can include a measuring device, in particular a current measuring device, which measures the current flowing between the counter electrode and the catalyst medium. This allows conclusions to be drawn about the reaction process.

[0014] The counter electrode can at least partially define the reaction chamber. In other words, the counter electrode can form part of the wall of the reaction chamber. The counter electrode can be located within the reaction chamber and / or protrude into it.

[0015] Preferably, the counter electrode is a capacitive counter electrode, and / or it can consist at least substantially of carbon and / or a metallic material. Crucially, it is preferred that the counter electrode has an electrically conductive surface. The counter electrode is preferably stable under the reaction conditions so that the reaction is not affected. According to a preferred embodiment, the device can include a reference electrode. This can be configured such that it forms part of the wall of the reaction chamber and / or is arranged within and / or projects into the reaction chamber. Such a reference electrode can be used to measure the relative potentials of the counter electrode or the catalyst medium.

[0016] The reference electrode can be connected to at least one voltage source. In particular, a measuring device, especially a voltage measuring device, can be arranged between the reference electrode and the voltage source. This allows a potential difference or a voltage to be measured between the reference electrode and the voltage source, the counter electrode, or the catalyst medium. This allows conclusions to be drawn about the voltage conditions or the respective potentials at the counter electrode and / or the catalyst medium.

[0017] Preferably, the reference electrode is chemically stable. This means that it does not dissolve, or only dissolves minimally, when in contact with a reaction medium in the reaction chamber. The reference electrode can consist at least substantially of platinum and / or silver and / or silver chloride and / or lithium iron phosphate, in particular of at least partially delithiated lithium iron phosphate, or incorporate such materials. This allows for both high conductivity and high chemical stability.

[0018] The catalyst medium preferably consists of a material that allows electrical contact via the voltage source. Preferably, the catalyst medium is arranged and / or contained within the reaction chamber. The catalyst medium can be located at least partially on the inner walls of the device surrounding the reaction chamber.

[0019] The catalyst medium can be designed as a supported system. For example, the catalyst medium can be a metal-supported catalyst, in particular comprising a conductive support material, preferably conductive carbon. It is also possible for the catalyst medium to be a complete catalyst, in particular consisting of conductive carbon, preferably heteroatom-doped conductive carbon. The catalyst medium can also be a material mixture with a conductive component, in particular a mixture of a catalyst and preferably carbon black or Nafion. The catalyst medium can be a material modified with conductive components, for example, a material surface-modified with a conductive compound. The catalyst medium can be a solid or a homogeneous catalyst in an immobilizing phase.

[0020] In a specific embodiment, the catalyst medium can be designed as a bulk catalyst, particularly in the form of particles. Several different catalyst media can be present in the reaction chamber of the device. It is also possible for the inner walls of the device, which surround the reaction chamber, to be at least partially covered with the catalyst medium. The catalyst medium can be designed as a bulk catalyst and have an electrically conductive surface for electrical contact. This allows the catalyst medium to be continuously supplied with an electrical potential, especially since charge exchange can take place via the electrically conductive surface. According to a preferred embodiment, the device can have exactly one voltage source. In this case, the entire catalyst medium can be supplied with a uniform electrical potential.

[0021] According to one possible embodiment of the invention, the catalyst medium can have several electrically separated sections. These sections can each be connected or connectable to the voltage source such that the different sections of the catalyst medium can be subjected to different potentials. This embodiment is based on the idea of ​​creating multiple areas within the reaction chamber where the catalyst medium is subjected to different potentials in order to optimize the reaction conditions. This allows, for example, for the consideration of changes in the properties of a fluid flowing longitudinally through the reaction chamber in a reaction process. For instance, adjustments can be made to accommodate different temperatures, concentrations, or other physical or chemical properties.

[0022] The device can have multiple voltage sources. Each voltage source can interact with a section of the catalyst medium to apply an electrical potential to that section.

[0023] In a specific embodiment, at least one, and in particular each, voltage source can be electrically connected or connectable to the catalyst medium in order to apply an electrical potential to the catalyst medium. In this case, a direct, electrically conductive connection between the respective voltage source and the catalyst medium is provided. It is also possible that at least one, and in particular each, voltage source is designed such that the catalyst medium can be applied an electrical potential without contact. Specifically, the voltage source can be designed such that the catalyst medium can be, or is, applied an electrical potential by electromagnetic induction. In this case, a direct electrical connection between the voltage source and the catalyst medium is not strictly necessary.Rather, such a non-contact voltage source can also generate an electrical potential over a certain distance.

[0024] At least one voltage source, in particular each voltage source, can be configured as a DC voltage source. It is also possible that at least one, in particular each, voltage source is configured as an AC voltage source. At least one voltage source, in particular each voltage source, can be configured as a switchable voltage source, so that either a DC voltage or an AC voltage can be generated. It is also conceivable to have embodiments in which one or more voltage sources are configured as DC voltage sources (N) and one or more voltage sources are configured as AC voltage sources.

[0025] A liquid and / or gaseous reaction medium can be provided in the reaction chamber or used in the process according to the invention. The reaction medium can contain a conducting salt and / or be electrically conductive itself. In other words, the reaction medium can contain a liquid reaction phase and a conducting salt, thus forming an electrolyte. The conducting salt can, for example, be LiClO₄. This creates an electrically conductive reaction medium. This medium can be in the liquid state or in a partially liquid and partially gaseous state. The electrically conductive reaction medium can influence the surface structure of the catalyst medium by applying a potential, thereby generating a voltage to the counter electrode.

[0026] The reaction medium can be formed at least partially, and in particular completely, by a starting material for the reaction, which is introduced into the device at one side.

[0027] Preferably, in the inventive method, the electrical potential of the catalyst medium is selected such that the stability of the catalyst medium is not affected or not significantly affected.

[0028] The method according to the invention can be configured such that the electrical potential of the catalyst medium is adjusted over the course of the chemical reaction. Specifically, this adjustment can counteract the aging of the catalyst medium. It is also possible to regenerate the catalyst medium or influence the reaction rate of the chemical reaction by adjusting the electrical potential. Preferably, the electrical potential of the catalyst medium can be adjusted, at least temporarily during the course of the chemical reaction, such that no current or at most a very small current flows, particularly between the counter electrode and the catalyst medium. A small current flows, in particular, when only a leakage current is present. Preferably, such a small current is less than 1 mA / cm². 2relative to the surface area of ​​a counter electrode or a reference electrode or the surface area of ​​the catalyst medium.

[0029] It is also possible that the potential applied to the catalyst medium is dynamically adjusted, i.e., exhibits a specific profile. This allows the performance of the chemical reaction to be optimized.

[0030] By adjusting the potential applied to the catalyst medium over time, the activity, reaction rate, conversion, yield, selectivity, stability, and turnover number can be optimized. It is also conceivable to design the system as a practically self-optimizing system in which certain quantities, such as the reaction conversion, or parameters, such as the reaction temperature, the pressure in the reaction chamber, or substance concentrations in the reaction medium, are measured. Depending on the measured parameters, the potential applied to the catalyst medium is adjusted to optimize the chemical reaction. For this purpose, the device can include appropriate measuring instruments for the respective quantities or parameters and a control unit for adjusting the electrical potential.The control unit can be connected to the measuring instruments and process the signals provided by the measuring instruments. The catalyst medium can be subjected to a constant potential or an alternating potential.

[0031] For further details of the invention, reference is made to the dependent claims and the following description of an exemplary embodiment with reference to the drawing. The drawing shows:

[0032] Figure 1 shows a device according to the present invention in a schematic representation, which is used for the hydrogenation of a substance A; and

[0033] Figure 2 shows the apparatus from Figure 1, which is used for the dehydration of a substance B. Figure 1 shows a schematic representation of an apparatus 1 for carrying out a chemical reaction, which is used for a process according to the invention for the hydrogenation of a substance A.

[0034] The device 1 is designed as a flow-tube reactor and has a reaction chamber 2 in which the chemical reaction can take place. A catalyst medium 3 is contained in the reaction chamber 2. This medium is schematically depicted as a bulk material in Figures 1 and 2 and, for example, has a carbon core coated with ruthenium. The catalyst medium 3 consists of a material that allows for electrical contact.

[0035] Furthermore, the device 1 includes a voltage source 4, which is electrically connected to the catalyst medium 3. This is shown schematically by the black line. The voltage source 4 can thus apply an electrical potential to the catalyst medium 3 in order to influence the course of the chemical reaction.

[0036] The device 1 comprises a counter electrode 5, which is also electrically connected to the voltage source 4 and can be subjected to a potential, so that a voltage can be applied between the catalyst medium 3 and the counter electrode 5. The counter electrode 5 partially delimits the reaction chamber 2 and is designed as a capacitive counter electrode. For example, the counter electrode 5 can consist at least substantially of carbon and / or a metallic material.

[0037] Furthermore, the device 1 includes a reference electrode 6 which is chemically stable under the prevailing environmental conditions and preferably consists of a partially delithiated lithium iron phosphate. According to a preferred embodiment, the reference electrode 6 also partially defines and projects into the reaction chamber 2.

[0038] The reference electrode 6 is connected to the voltage source 4. The voltage between the reference electrode 6 and the catalyst medium 3 can be measured by a suitable voltage measuring device 7. Similarly, the current flowing between the counter electrode 5 and the voltage source 4 can be monitored by a suitable current measuring device 8.

[0039] A reaction medium 9 is provided in the reaction chamber 2. This is a liquid reaction medium containing a conducting salt, for example LiClO4, to establish electrical conductivity. For example, the reaction medium 9 can contain or consist of compound A, which, in its liquid state, flows into the reaction chamber 2 of the device 1, for example, from above or from the outside, as schematically illustrated by the arrow in Figure 1.

[0040] Furthermore, the present process provides for gaseous hydrogen to also flow into reaction chamber 2, for example, from above. In this reaction chamber, the reaction, specifically a hydrogenation, to form compound B takes place. This compound exits reaction chamber 2, for example, downwards. The catalyst medium 3 is subjected to an electrical potential by the voltage source 4. The counter electrode 5 can also be subjected to an electrical potential relative to this, so that a voltage is present between the catalyst medium 3 and the counter electrode 5. In other words, a potential can be established at the counter electrode 5 that corresponds to the current flowing due to the potential applied to the catalyst medium 3. This allows the reaction, in this case the hydrogenation, to be electrochemically controlled, thus significantly improving the performance of the catalyst medium 3.In other words, the interface between the catalyst medium 3 and the reaction medium 9 is influenced accordingly by applying an electrical potential to the catalyst medium 3.

[0041] Figure 2 also shows a device 1 according to the invention for carrying out a chemical reaction. This device is constructed in principle in the same way as the device 1 of Figure 1. However, Figure 2 schematically illustrates a process in which a compound B is reacted, specifically dehydrated. This produces compound A and gaseous hydrogen. As in the process shown in Figure 1, the reaction is electrochemically controlled by applying an electrical potential to the catalyst medium 3 and the counter electrode 5 using the voltage source 4, so that a voltage is present between the catalyst medium 3 and the counter electrode 5.

[0042] Reference symbol list

[0043] 1 Device

[0044] 2 Reaction chamber 3 Catalyst medium

[0045] 4 Voltage source

[0046] 5 Counter electrode

[0047] 6 Reference electrode

[0048] 7 Voltage measuring device 8 Current measuring device

[0049] 9 Reaction medium

Claims

REQUIREMENTS 1. Device (1) for carrying out a chemical reaction, in particular a thermally catalyzed reaction, comprising a reaction space (2) in which the chemical reaction can take place, a catalyst medium (3) and at least one voltage source (4) which interacts or can interact with the catalyst medium (3) in such a way that the catalyst medium (3) can be subjected to an electrical potential in order to influence the course of the chemical reaction.

2. Device (1) according to claim 1 , characterized in that the device (1) is designed as a reactor, in particular as a flow tube reactor or as a stirred tank reactor.

3. Device (1) according to claim 1 or 2, characterized in that the device (1) has a counter electrode (5).

4. Device (1) according to claim 3, characterized in that the counter electrode (5) at least partially limits the reaction space (2) and / or is arranged in the reaction space (2) and / or projects into it.

5. Device (1) according to claim 3 or 4, characterized in that the counter electrode (5) is a capacitive counter electrode (5), and / or that the counter electrode (5) consists at least substantially of carbon and / or a metallic material.

6. Device (1) according to one of the preceding claims, characterized in that the device (1) has a reference electrode (6).

7. Device (1) according to claim 6, characterized in that the reference electrode (6) is chemically stable, and / or that the reference electrode (6) consists at least substantially of platinum and / or silver and / or silver chloride and / or lithium iron phosphate, in particular an at least partially delithiated lithium iron phosphate.

8. Device (1) according to one of the preceding claims, characterized in that the catalyst medium (3) consists of a material which enables electrical contact by the voltage source (4), and / or that the catalyst medium (3) is designed as a solid, and / or that the catalyst medium is designed as a homogeneous catalyst in an immobilizing phase.

9. Device (1) according to one of the preceding claims, characterized in that the catalyst medium (3) is designed as a metal-supported catalyst, wherein it in particular comprises a conductive support material, preferably conductive carbon, and / or that the catalyst medium (3) is designed as a complete catalyst, wherein it in particular consists of a conductive carbon, preferably of a heteroatom-doped conductive carbon, and / or that the catalyst medium (3) consists of a material mixture with a conductive component, in particular a mixture of a catalyst and preferably carbon black or Nafion, and / or that the catalyst medium (3) comprises a conductive component modified material, for example, a material surface-modified with a conductive compound.

10. Device (1) according to one of the preceding claims, characterized in that the device (1) has exactly one voltage source (4).

11. Device (1) according to one of the preceding claims, characterized in that the catalyst medium (3) has different electrically separated sections, each of which is connected or connectable to the at least one voltage source (4) in such a way that the different sections of the catalyst medium (3) can be subjected to different potentials.

12. Device (1) according to claim 11, characterized in that the device (1) has several voltage sources (4), wherein each voltage source (4) interacts or can interact with a section of the catalyst medium (3) in order to apply an electrical potential to the respective section of the catalyst medium (3).

13. Device (1) according to one of the preceding claims, characterized in that at least one, in particular each, voltage source (4) is electrically connected or connectable to the catalyst medium (3) in order to directly apply an electrical potential to the catalyst medium (3), and / or that at least one, in particular each, voltage source (4) is designed such that the catalyst medium (3) can be applied to an electrical potential without contact, in particular by induction.

14. Device (1) according to one of the preceding claims, characterized in that a liquid and / or gaseous reaction medium (9) is provided in the reaction chamber (2).

15. Device (1) according to claim 14, characterized in that the reaction medium (9) contains a conducting salt and / or is itself electrically conductive.

16. Method for carrying out a chemical reaction, in particular a thermally catalyzed reaction, using a device (1) according to one of the preceding claims, wherein the catalyst medium (3) is subjected to an electrical potential in order to influence the reaction process.

17. Method according to claim 16, characterized in that the electrical potential of the catalyst medium (3) is selected such that the stability of the reaction medium (9) is not affected.

18. Method according to claim 16 or 17, characterized in that the electrical potential of the catalyst medium (3) is adjusted over the duration of the chemical reaction.

19. Method according to claim 18, characterized in that the aging of the catalyst medium (3) is counteracted by adjusting the electrical potential of the catalyst medium (3) and / or the catalyst medium is regenerated and / or the reaction conversion is influenced, and / or the electrical potential of the catalyst medium (3) is adjusted at least temporarily such that no current or only a small current flows.

20. Device (1) according to any one of claims 1 to 15 or method according to any one of claims 16 to 19, characterized in that the chemical reaction is or comprises a hydrogenation, a dehydrogenation, a reforming reaction, an oxidation, a deoxygenation, a coupling reaction, a cleavage reaction and / or a functionalization.

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