Method for producing organic carbonates

Abstract

The present invention relates to a method for producing an organic carbonate, particularly diethyl carbonate, comprising a catalytic reaction of a corresponding alcohol (ROH) and carbon dioxide, wherein R is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably an ethyl group, and the water produced during the catalytic reaction is separated via at least one inorganic membrane (21) and / or at least one hybrid membrane (21), characterized in that the catalyst comprises cerium oxide (CeO2), and the catalytic reaction is carried out at a temperature of at least 80°C and a pressure of at least 5 bar.

Description

Technical Field

[0001] The present invention relates to a method for producing organic carbonates, particularly diethyl carbonate, including the catalytic reaction of alcohol (ROH) and carbon dioxide, where R is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably an ethyl group, and the water generated during the catalytic reaction is separated through at least one inorganic membrane and / or at least one hybrid membrane.

Background Art

[0002] The present invention relates to a reactor for producing organic carbonates, particularly diethyl carbonate. The reactor has at least one reactor module, and the reactor module has a reaction chamber. The reaction chamber is separated from a discharge chamber for discharging water from the reaction chamber by at least one inorganic membrane and / or at least one hybrid membrane.

[0003] Organic carbonates are used as starting materials for synthesizing, in particular, plastics, pharmaceuticals, veterinary drug active ingredients, pesticides, dyes, and photochemicals, and as electrolytes for lithium-ion batteries. Currently, organic carbonates are mainly used as raw materials in the chemical industry, but they are also suitable as fuels or fuel additives for reducing exhaust gases. In particular, diethyl carbonate has proven to be particularly advantageous as a fuel additive. By mixing, emissions of carbon monoxide (CO), particulate matter, and smoke are reduced. When DEC is produced from renewable resources, fossil-derived CO2 emissions are also reduced. In particular, compared to the starting product ethanol, the potential for mixing with diesel holds great ecological and economic promise.

[0004] The synthesis of organic carbonates is carried out using CO2 and the corresponding alcohol as starting components, and organic carbonates and water are generated during the catalytic reaction process. Therefore, the reaction formula for the catalytic reaction generally is as follows.

[0005]

Chemical Formula

[0006] For example, using ethanol as the alcohol, diethyl carbonate can be produced.

[0007] [ka]

[0008] As the final product of a combustion process, CO2 is thermodynamically stable and reacts only with high energy input. The formation of organic carbonates from CO2 and alcohols is exothermic and does not proceed spontaneously at room temperature. Removing water produced during the catalytic reaction has been shown to be quite advantageous to the reaction. Therefore, water-binding substances (chemical water traps) have been used to remove water.

[0009] However, this method is not very practical for large-scale production, as the water-retaining agent must be removed from the reaction mixture and regenerated, or discarded. Furthermore, there is a risk of contamination of the final product. Therefore, these methods are not suitable for the large-scale industrial production of organic carbonates.

[0010] Wang et al. (2017) studied Ce under ambient pressure. 0.8 Zr 0.2 This document discloses a method and reactor for producing diethyl carbonate using an O2 catalyst. In this method, water is continuously discharged through an inorganic membrane during the reaction. However, according to this document, this method only achieves a very low yield of about 0.06%.

[0011] Chinese Patent Application Publication No. 112657434 discloses a further method and reactor for electrochemical synthesis operating in a somewhat higher pressure and temperature range. Transition metals such as Cu, Fe, Ni, Co, or Zn are used as catalysts. These metals are supported on a CeO2 support, which provides mechanical support. The generated water is separated by a polyimide membrane. To initiate the reaction, an electric current must be supplied through electrodes. This presupposes higher energy input and a more complex reactor structure. Furthermore, this embodiment also proved unsatisfactory.

[0012] Kuenen et al. (2016) proposed using a cerium oxide catalyst in combination with a PEEK chitosan membrane (polymer membrane). This yielded insufficient results. The paper describes the direct synthesis of diethyl carbonate from methanol and CO2 in a membrane reactor by in-situ separation of water. Furthermore, these data were obtained using simulations, and it cannot be stated whether the provided membrane can realistically maintain the specified selectivity even at increasing temperatures. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Chinese Patent Application Publication No. 112657434 Specification [Non-patent literature]

[0014] [Non-Patent Document 1] Wang, J., Hao, Z., Wohlrab, S., 2017. Continuous CO2 esterification to diethyl carbonate (DEC) at atmospheric pressure: application of porous membranes for in situ H2O removal. Green Chem. 19, 3595-3600. https: / / doi.org / 10.1039 / C7GC00916J [Non-Patent Document 2] Kuenen, HJ, Mengers, HJ, van der Ham, AGJ, & Kiss, AA (2016). Novel Process for Conversion of CO2 to Dimethyl Carbonate using Catalytic Membrane Reactors. In 26 European Symposium on Computer Aided Process Engineering, 2016 (Vol. 38, pp. 991 -996). (Computer Aided Chemical Engineering; Vol. 38). Elsevier. https: / / doi.org / 10.1016 / B978-0-444-63428-3.50170-3 [Non-Patent Document 3] Vane LM. Review: Membrane Materials for the Removal of Water from Industrial Solvents by Pervaporation and Vapor Permeation. J Chem Technol Biotechnol. 2019;94(2):343-365. doi:10.1002 / jctb.5839. PMID: 30930521 ; PMCID: PMC6436640 [Overview of the project] [Problems that the invention aims to solve]

[0015] An object of the present invention is to provide a method and a reactor capable of producing a large amount of organic carbonate and achieving a higher yield.

Means for Solving the Problems

[0016] This problem is solved according to the present invention in that the catalytic reaction is carried out at a temperature of at least 80° C. and a pressure of at least 5 bar, and the catalyst contains at least one substance among cerium oxide (CeO2), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5, or an alloy containing copper and nickel.

[0017] This problem is also solved in that the catalyst is disposed in the reaction chamber and the catalyst contains at least one substance among cerium oxide (CeO2), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5, or an alloy containing copper and nickel.

[0018] Iron, copper, magnesium, and / or nickel (Fe, Cu, Mg, and / or Ni) of the specified metals are preferably part of the catalyst in metallic form, but may also be present in other forms, such as salts, oxides, or organic compounds.

[0019] Preferably, this catalyst is at least partially immobilized on a carrier material. This carrier material may be, for example, activated carbon. In particular, when this catalyst contains metals such as Fe, Cu, Mg, and / or Ni, this is advantageous. The carrier material may be connected to a membrane and / or provided to be part of a membrane. For example, at least one layer containing the carrier material and the catalyst may be disposed on the membrane, and at this time, this membrane is preferably water-permeable and / or porous. Thereby, the reaction occurs near the membrane.

[0020] Inorganic membranes and hybrid membranes have been shown to be particularly well-suited when used at higher pressures and temperatures. This is because even under such conditions, these membranes have a high selectivity for water and can separate large amounts of water from the reaction chamber. Organic membranes may swell in some situations and may become increasingly impermeable to water. By using an inorganic or hybrid membrane, this can be avoided.

[0021] In this case, the membrane is permeable to water. Preferably, the membrane is substantially impermeable to the starting materials, i.e., CO2 and / or alcohol, or at least impermeable compared to the permeability of the membrane to water, and / or substantially impermeable to the final product, i.e., organic carbonate, or at least impermeable compared to the permeability of the membrane to water. Thus, the water generated can be selectively discharged from the space where the reaction occurs, and the reaction equilibrium can be shifted towards the organic carbonate side.

[0022] At this time, this membrane can have multiple layers with different materials or properties. Multiple membranes can also separate water in parallel with each other, or multiple membranes may be arranged in parallel with each other between the reaction chamber and the separation chamber. Here, "in parallel with each other" does not mean that the membrane surfaces are spatially aligned with each other, but rather that the two membranes are not arranged in sequence between the reaction chamber and the separation chamber, but rather that water separation occurs in parallel with each other on the membranes.

[0023] Generally, membranes can be divided into three different materials: organic membranes, inorganic membranes, and both compounds (hybrid membranes).

[0024] Organic polymer films are widely used in film technology because they are relatively inexpensive and their specifications can be easily tailored to customer needs through polymer selection or easily controllable manufacturing processes. However, at the high temperatures required in our processes, polymer films tend to swell, significantly reducing their selectivity. Pervaporation films on polymer bases described in the literature are described at temperatures below 60°C. However, since the method based on our invention requires temperatures exceeding 100°C, these films do not achieve sufficient selectivity at high temperatures. Although some manufacturers have introduced experimental special films for temperatures below 110°C, their properties are clearly degraded. Other conventional high-temperature film materials, such as polyamides, do not possess sufficiently good performance (selectivity).

[0025] Inorganic films are generally manufactured from ceramic or zeolite-based materials, making them suitable for high-temperature and highly aggressive media. Compared to polymer films, their manufacturing is more complex, and there is less possibility of adapting specifications to customer requirements. Furthermore, inorganic films are more expensive and more susceptible to mechanical stress.

[0026] So-called hybrid films, which contain both organic and inorganic materials, are also known.

[0027] Preferably, the film, and more preferably the hybrid film, has at least one layer that is at least predominantly inorganic and / or at least one layer that is at least predominantly organic. The at least predominantly inorganic layer may include at least one ceramic (e.g., oxide ceramics, and / or aluminum-based, zirconium oxide-based, and / or silicon oxide-based) carbide and / or zeolite material or substance. The at least predominantly organic layer may include a material or substance such as PVA (polyvinyl alcohol).

[0028] The film, preferably a single hybrid film, has at least one carrier layer that is at least predominantly inorganic, preferably containing at least one ceramic, and / or the film may be configured to have at least one further layer, preferably containing at least one organic material, particularly preferably a polymer material. Preferably, the further layer has higher selectivity for water than the carrier layer.

[0029] The compound, consisting of an inorganic support and an organic layer, minimizes the swelling of the organic material, which is expected to result in excellent selectivity even at high temperatures.

[0030] Particularly preferable is that the film includes at least one polymer metal carbide film. This film has particularly excellent temperature stability.

[0031] A hybrid film may be configured to have at least one single layer containing organic and inorganic materials. A single layer means a layer that cannot be subdivided into various sublayers depending on its material. The organic and inorganic materials may be mixed together. Such a film is sometimes called a mixed matrix film.

[0032] The hybrid film may be configured to have at least one layer containing an organic matrix, in which inorganic materials, preferably particles and / or preferably a catalyst and / or an adsorbent are arranged.

[0033] Further examples of film materials are shown by Vane et al.

[0034] Surprisingly, it was demonstrated that particularly high yields could be achieved when the specified substance was used as a catalyst and high temperature and pressure were applied. The power supply required for electrochemical CO2 reduction using transition metals could be omitted. Here, catalysts containing cerium oxide (CeO2) were shown to be extremely efficient. Such catalysts yielded particularly high yields.

[0035] Surprisingly, despite the reaction being exothermic, meaning heat is released, it was shown that high temperatures above 80°C favorably influence both yield and reaction rate.

[0036] The reaction chamber of the reactor module is the space where the catalyst is placed, the starting materials are supplied, and the catalytic reaction takes place. It is crucial that the pressure and temperature in this reaction chamber match the set values, thereby ensuring the reaction proceeds efficiently and as completely as possible.

[0037] The discharge chamber, preferably without a catalyst, is used to discharge water that is discharged from the reaction chamber to the discharge chamber via a membrane. The water produced by the reaction separates into the discharge chamber by passing through the membrane, where it can be discharged, for example, through a drain or stored in a water tank.

[0038] Preferably, the membrane is provided to define the reaction chamber on at least one side. That is, the catalyst and the membrane may be arranged adjacent to each other. Thus, the water generated can be removed through the membrane immediately after generation. This applies to both the method and the reactor according to the present invention.

[0039] Preferably, the pressure in the discharge chamber differs from the pressure in the reaction chamber by less than 6 bar. Thus, excessive pressure loading on the membrane is prevented.

[0040] In this case, the catalytic reaction can be carried out continuously or discontinuously.

[0041] A reactor for producing organic carbonates, particularly diethyl carbonate, may also be advantageous, the reactor having at least one reactor module, the reactor module having a reaction chamber, the reaction chamber being separated from a discharge chamber for discharging water from the reaction chamber through at least one organic, inorganic, and / or hybrid membrane, the catalyst being immobilized in the reaction chamber, preferably on a molecular sieve or similar support material, such as having at least one polymer, and the catalyst comprising at least one substance from among cerium oxide (CeO2), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5, or an alloy containing copper and nickel.

[0042] Accordingly, a method for producing organic carbonates, particularly diethyl carbonate, comprising a catalytic reaction of a corresponding alcohol (ROH) and carbon dioxide, may also be advantageous, where R is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably ethyl alcohol, water produced during the catalytic reaction is separated via at least one organic or inorganic membrane and / or hybrid membrane, the catalyst is immobilized on a molecular sieve or similar support material before the catalytic reaction is carried out, the catalytic reaction is carried out at a temperature of at least 80°C and a pressure of at least 5 bar, and the catalyst comprises at least one substance from among cerium oxide (CeO2), ZrO2, CrO2, activated carbon (Fe, Cu, Mg, Ni), SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5, or an alloy containing copper and nickel.

[0043] Embodiments based on the last two paragraphs are particularly advantageous because they allow for particularly easy and effective implementation. These can be combined with all the special features and embodiments described herein or in the claims. By placing the catalyst on a molecular sieve, i.e., molecular sieve or similar support material, a particularly large surface area, which is particularly important for the catalytic acceleration of the method, is achieved. Placement on a molecular sieve is particularly advantageous in combination with this membrane, because the complex membrane shape, which provides as much membrane surface area as possible for draining water and gives the reaction chamber a spatially angled shape, can be combined with as many catalysts as possible, particularly well. Despite the complex and spatially angled structure of the reaction chamber, the reaction chamber can be easily and densely filled with molecular sieves, which can fill the space well due to their bulk shape. That is, molecular sieves usually exist in a fluid bulk shape, for example, in granular or pellet form. Therefore, it is possible to combine a particularly large membrane surface area with a particularly large catalyst surface area in a narrow space, thereby resulting in a synergistic improvement in yield. In addition, attaching it to a support material has the advantage of eliminating loosening in the reaction chamber that could cause blockage.

[0044] The reaction is particularly advantageous when carried out at a temperature of at least 100°C, preferably at least 120°C, and especially preferably 110°C to 150°C, and / or when carried out at a pressure of at least 10 bar, preferably 12 bar or more, and / or 15 bar or more, particularly preferably 20 bar to 40 bar. As mentioned above, these temperature and pressure ranges allow for particularly high yields, which initially seems paradoxical due to the exothermic nature of the reaction. Particularly high yields were achieved at temperatures of 110°C to 150°C and / or pressures of 12 bar or more, especially 20 bar to 40 bar.

[0045] In a preferred embodiment, separation across the membrane is carried out by membrane permeation and / or vapor permeation. Therefore, particularly efficient separation of water is possible, especially at higher pressures and temperatures. Accordingly, the membrane may be designed to separate water by membrane permeation and / or vapor permeation.

[0046] It is particularly advantageous if the separation is carried out via at least one carbon membrane and / or at least one ceramic membrane, especially preferably at least one zeolite membrane. Such membranes, especially zeolite membranes, have been shown to have good selectivity for water despite high pressure and high temperature, and to remain stable over long periods of time. The same is true if the membrane is provided to include a carbon membrane and / or a ceramic membrane, especially preferably a zeolite membrane.

[0047] Furthermore, it is advantageous if the catalytic reaction takes place in at least one reactor module where the catalyst is located. This allows for a compact and controlled reaction process within the reactor module. The reactor module may have one or more reaction chambers where the catalyst is located and the catalytic reaction takes place. It is particularly advantageous if the reaction chamber is separated from an outlet chamber for draining water from the reaction chamber by at least one inorganic membrane and / or hybrid membrane. Thus, it becomes possible to separate water immediately after its generation in the catalytic reaction. This minimizes the residence time of water in the catalyst.

[0048] In this sense, it is advantageous for the reactor to have at least one carbon dioxide source and at least one alcohol source (ROH), where R is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably ethyl alcohol. These sources may be, for example, storage media for substances, i.e., CO2 bottles or alcohol-containing containers. The sources themselves may directly produce substances; for example, the carbon dioxide source may be an internal combustion engine, and carbon dioxide is produced by the combustion of fuel. Further carbon dioxide sources may be, for example, systems in which carbon dioxide is biologically released by fermentation, or chemical systems. Systems for obtaining carbon dioxide directly from ambient air (direct air capture technology) are also possible.

[0049] It is particularly advantageous when, during a catalytic reaction, the reaction mixture flows through a reactor module within the circuit. For example, an efficient reaction process is achieved when the mixture of starting materials and the final product is constantly mixed, the catalyst is constantly supplied with starting materials, and the membrane is constantly supplied with water. In this sense, it is also advantageous when the reactor has at least one circuit, along which at least one supply pump transports a mixture of liquids and / or gases, and the reactor module is part of this circuit, preferably configured such that a carbon dioxide supply source and an alcohol supply source are fluidly connected to this circuit.

[0050] To achieve particularly efficient conversion, the reaction mixture may be configured to flow through multiple parallel-connected reactor modules within the circuit during the catalytic reaction. The parallel connection of the reactor modules can further increase the amount of converted starting material. This is particularly advantageous in discontinuous method processes. The same applies when the circuit has multiple reactor modules connected in parallel with each other. Alternatively, multiple reactor modules may be connected in series with each other. This allows for the achievement of higher concentrations.

[0051] Multiple circuits can be configured to be connected in series with each other, and at least one first and second circuit each having at least one reactor module. In other words, the reaction mixture can be configured to flow through the first circuit, then at least partially through the second circuit, and then, in the process of flowing through the second circuit, through at least one further reactor module. In this case, different reaction equilibria may be set within these circuits. This can be particularly effective when the method is carried out continuously.

[0052] Preferably, the catalytic reaction is carried out until the reaction mixture has a threshold weight percentage of the final product, preferably at least 80% wt, and when or after the threshold weight percentage is reached, the reaction mixture is discharged from the reactor module, and after discharge, preferably carbon dioxide, alcohol, or at least one other substance is separated from the organic carbonate as the final product. This type of discontinuous reaction guide allows for rapid achievement of a high degree of conversion. At this point, the reaction mixture may continue to flow through the circuit until the threshold weight percentage is reached. In this sense, it may also be advantageous that, after or during discharge, carbon dioxide is separated from the reaction mixture, preferably by a droplet separator, and / or alcohol and / or other substances are separated from the reaction mixture, particularly preferably by distillation and / or by at least one membrane. Correspondingly, it may also be advantageous that the circuit has at least one discharge channel leading out of the circuit for discharging the final product, and this discharge channel preferably includes at least one condenser and / or at least a droplet separator, and particularly preferably a carbon dioxide return channel for returning carbon dioxide from the droplet separator back into the circuit.

[0053] At this point, the separated substances can be returned to the circuit. That is, there may be at least one return channel for each substance to return to the circuit. In this case, the substances, i.e., carbon dioxide and alcohol, may be processed, for example, by compression, heating, cooling, or purification before being returned.

[0054] Furthermore, it is advantageous if the carbon dioxide and alcohol are sent to a reactor after emission to carry out further catalytic reactions. This allows for the initiation of a new reaction.

[0055] To prevent excessive load from being applied to the membrane, during the catalytic reaction, a pressure can be set on the membrane side opposite the reaction mixture, which is less than 10 bar, preferably less than 6 bar, that is different from the pressure of the reaction mixture.

[0056] Furthermore, it is advantageous if a sweep gas flows along the membrane side opposite the reaction mixture, and this sweep gas is preferably carbon dioxide. The flow of the sweep gas carries away water from the membrane surface, thereby improving water separation. The sweep gas can be used to regulate the pressure on this membrane side. Alternatively, a mixture of the aforementioned gases, such as nitrogen (N2), ethanol vapor, or a mixture, preferably a CO2-ethanol vapor mixture, can also be used as the sweep gas.

[0057] It is particularly advantageous to immobilize the catalyst on a molecular sieve before the catalytic reaction, preferably by coating the molecular sieve with a cerium salt, especially preferably a cerium halogen salt such as cerium chloride and / or cerium(III) nitrate, and then calcining the molecular sieve. This allows for a particularly large catalyst surface area, as described above. The same applies when the reaction chamber is provided to be substantially filled with the molecular sieve and the catalyst immobilized on it.

[0058] Preferably, the membrane is implemented as at least one membrane tube, with at least a portion of the discharge chamber located inside. Implementing it as a tube easily improves the transport of water using the sweep gas. Accordingly, water generated during the catalytic reaction can also be separated through at least one membrane implemented as at least one membrane tube.

[0059] It is particularly advantageous if the membrane has a selectivity α for at least 100 units of water at a temperature of 80°C and a pressure of 5 bar, and / or a selectivity α for at least 100 units of water at a temperature of 100°C and a pressure of 10 bar. This allows for the separation of water to be as pure as possible. A selectivity for 100 units of water means that the membrane allows only 1 unit of ethanol to pass through for every 100 units of water.

[0060] Furthermore, in order to set the temperature of the catalytic reaction, the circuit may have at least one temperature control source for adjusting the temperature of the mixture in the circuit, and / or the temperature of the mixture in the circuit may be adjusted by at least one temperature control source.

[0061] In a preferred embodiment, the reactor module is configured to have an inlet connected to a feed channel of the circuit, which is fluid-connected to the reaction chamber, and an outlet connected to a retaining fluid channel of the circuit, preferably located at opposite ends of the reaction chamber. In this case, the feed channel and the retaining fluid channel are connected to each other directly or indirectly, in addition to the connection via the reactor module, thereby forming a circuit.

[0062] It is particularly advantageous if at least one membrane tube protrudes into the reaction chamber, preferably extending from one end of the chamber to the other. This allows water to be removed from the reaction chamber along its entire length, and a particularly large amount of starting material is converted to organic carbonates throughout the entire reaction chamber due to the low amount of water.

[0063] It is even more advantageous if the membrane is fluidly connected to a sweep gas source at a first end region and to a water discharge channel for discharging water at a second end region. This achieves particularly efficient water transport.

[0064] In this sense, the first end is closed, and the fluid connection to the sweep gas supply source can be made by an immersion tube protruding into the membrane tube via the second end. This allows for a configuration in which the sweep gas is connected to one side of the reaction chamber. Furthermore, it becomes possible to use a membrane tube that is already manufactured industrially with one end closed.

[0065] To efficiently separate water, the water discharge channel may be configured to include a droplet separator for separating the sweep gas, preferably a condenser connected upstream of the droplet separator, and / or a sweep gas return line for returning the obtained sweep gas back to the membrane tube.

[0066] The sweep gas can be, for example, carbon dioxide. Even if some of it enters the reaction chamber through the membrane, it will not contaminate the mixture. Alternatively, other gases can be used, such as nitrogen (N2), ethanol vapor or a mixture of the aforementioned gases, preferably a CO2-ethanol vapor mixture.

[0067] The separation of water is further improved if at least five, preferably six or seven, membrane tubes are arranged within the reactor module.

[0068] In the following, the present invention will be described in the figures using non-limiting embodiments based on the present invention. [Brief explanation of the drawing]

[0069] [Figure 1a] This is a longitudinal cross-sectional view of a reactor module according to the present invention, which is attached to a reactor according to the present invention to carry out a method according to the present invention. [Figure 1b]This is a cross-sectional view of the reactor module cut along line AA in Figure 1a. [Figure 2] This is a flow diagram of a reactor according to the present invention according to a first embodiment, using the method according to the present invention. [Modes for carrying out the invention]

[0070] The reactor module 1 shown in Figures 1a and 1b has a vertically elongated, substantially cylindrical shape. At one end is an inlet region 2 having a connection portion 2a for connecting to a feed channel. This supplies carbon dioxide and alcohol to the reactor module. The inlet region 2 is connected via an inlet 3 to the first end 4a of a reaction chamber 4, which is filled with pelletized molecular sieves (not shown) and a calcined catalyst on top of them, so that the starting material can be converted into an organic carbonate through the catalyst in the reaction chamber 4. The reaction chamber 4 extends over most of the reactor module 1, and for clarity, the reactor module 1 is shown interrupted in the region of the reaction chamber 4.

[0071] The reaction chamber 4 is fluidly connected to the outlet region 6 via an outlet 5 at its opposing second end 4b. The outlet region 6 has a connection 6a for connecting to a retaining liquid channel. This allows the retaining liquid, which may contain the final product mixed with unconverted starting materials, to be discharged from the reaction chamber 4.

[0072] Along the longitudinal extension of the reaction chamber 4, a total of seven membrane tubes 7 extend into the reaction chamber 4, passing through the end wall 8 of the outlet region 6 and extending further into the outlet region 6, and continuing to the first end 4a of the reaction chamber 4. At this point, the end wall 8 is tightly connected to the membrane tubes 7. The membrane tubes 7 terminate in the water collection region 9 located behind the end wall 9. That is, the outer wall of the membrane tube 7 faces the reaction chamber 4, while the inner wall of the membrane tube 7 faces the discharge chamber 10, which is formed from the internal space of the membrane tube 7 and does not contain the catalyst.

[0073] At the second end 7b of the membrane tube 7, the membrane tube 7 is open and fluidly connected to the water collection region 9. As a result, water flowing from the reaction chamber 4 to the discharge chamber 10 through the membrane tube 7 is collected in the water collection region 9 and can be discharged to the discharge channel through the connection part 9a of the water collection region 9.

[0074] At the first end 7a, which faces the first end 4a of the reaction chamber 4, the membrane tube 7 is closed. The immersion tube 11 is inserted into the membrane tube 7 via the second end 7b, extends to the first end 7a, and opens there. As a result, the sweep gas is carried through the immersion tube 11 to the discharge chamber 10 in the region of the first end 7a. The immersion tube 11 restricts the discharge chamber 10 to the narrow space between the outside of the immersion tube 11 and the inside of the membrane tube 7.

[0075] The immersion tube 11 extends from the second end 7b through the water collection area 9 and through a further end wall 12 of the reactor module 1, which is also tightly connected to the immersion tube 11. Beyond the end wall 12, the immersion tube 11 is fluidly connectable to a sweep gas supply source.

[0076] Figure 2 illustrates an embodiment of a reactor according to the present invention in more detail using a flow diagram. In this embodiment, the reactor has a reactor module 20, which has a membrane 21 that separates the reaction chamber 4 from the discharge chamber 10. The reaction chamber 4 is part of a circuit 22 having a circuit pump 23, which moves its fluid in one direction. The circuit 22 may have channels, such as piping, to guide the fluid. The membrane 21 includes at least one inorganic membrane and / or at least one hybrid membrane.

[0077] The reaction chamber is connected via an inlet to the feed channel 29 of circuit 22, which is downstream of the circuit pump 23, and via an outlet to the retaining fluid channel 30, which is upstream of the circuit pump 23. "Connected" in this sense means a fluid connection. Therefore, the circuit pump 23 acts as a supply pump.

[0078] Figure 2 shows only the reactor module 20. However, as already explained, the feed channel 29 can also be branched upstream of the reactor module to supply multiple reactor modules 20 in parallel. Accordingly, the retaining liquid channel 30 will also be branched to collect the reaction mixture from the reactor modules and combine it into a single channel upstream of the circuit pump 23.

[0079] Furthermore, an ethanol supply line 24 is connected to the circuit 22, and ethanol is supplied into the circuit from the ethanol tank 25 by a feed pump via this supply line 24. Preferably, the supply line 24 is located downstream of the circuit pump 23 and upstream of the reactor module 20, as shown in this embodiment.

[0080] Furthermore, a carbon dioxide (CO2) supply line 26 is connected to the circuit 22, and CO2 is supplied to the circuit from the carbon dioxide tank 27 via this supply line 26, by additional feed pumps as needed. Preferably, the supply line 26 is located downstream of the circuit pump 23 and upstream of the reactor module 20, as shown in this embodiment.

[0081] Circuit 22 is also connected to a discharge channel 28 between the reaction chamber 4 and the circuit pump 23, and the retaining liquid can be discharged into the retaining liquid tank 31 through this discharge channel 28.

[0082] The discharge chamber 10 is connected to a carbon dioxide supply source, preferably the same carbon dioxide tank 27, via a further supply line 35. Thus, CO2 acts as a sweep gas in the discharge chamber 10, carrying water away from the membrane 21.

[0083] The discharge chamber 10 is connected to a water discharge channel 32, through which water is carried out of the discharge chamber 10 and sent into the water tank 34. Preferably, the water discharge channel 32 has a condenser 33, through which the water condenses before being sent into the water tank 34.

[0084] Preferably, the reactor module 20 is temperature-controlled by a temperature-controlled fluid, particularly preferably oil, which is supplied to and discharged from the reactor module 20 via a temperature-controlled channel 36.

Claims

1. A process for the production of organic carbonates, particularly diethyl carbonate, which involves a catalytic reaction of the corresponding alcohol (ROH) with carbon dioxide, where R is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably an ethyl group, and the water generated during the catalytic reaction is separated through at least one inorganic membrane (21) and / or at least one hybrid membrane (21), wherein the catalytic reaction is carried out at a temperature of at least 80 °C and a pressure of at least 5 bar, and the catalyst comprises cerium oxide (CeO ２ ), ZrO ２ , CrO ２ , Fe, Cu, Mg, Ni, SiO ２ , Al ２ O ３ , TiO, MoO, BiO, ZnO, Ta ２ O ５ , Nb ２ O ５ , or an alloy containing copper and nickel, characterized in that it contains at least one of these substances.

2. The method according to claim 1, characterized in that the reaction is carried out at a temperature of at least 100°C, preferably at least 120°C, and particularly preferably 110°C to 150°C, and / or the reaction is carried out at a pressure of at least 10 bar, preferably 20 bar to 40 bar.

3. The method according to claim 1 or 2, characterized in that the separation via the membrane (31) is carried out by membrane permeation and / or vapor permeation.

4. The method according to any one of claims 1 to 3, characterized in that the separation is carried out via at least one carbon film and / or at least one ceramic film, particularly preferably at least one zeolite film, and / or the separation is carried out via at least one film having at least one layer that is at least predominantly inorganic and / or at least one layer that is at least predominantly organic.

5. The method according to any one of claims 1 to 4, characterized in that the catalytic reaction is carried out in at least one reactor module (20) in which the catalyst is located, and preferably the reaction chamber (4) is separated from a discharge chamber (10) for discharging water from the reaction chamber (4) by at least one inorganic membrane (21) and / or at least one hybrid membrane (21).

6. The method according to claim 5, characterized in that during the catalytic reaction, the reaction mixture flows through the reactor module (20) within the circuit (22).

7. The method according to claim 6, characterized in that during the catalytic reaction, the reaction mixture flows through a plurality of parallel-connected reactor modules (20) within the circuit (22).

8. The method according to any one of claims 1 to 7, characterized in that the catalytic reaction is carried out until the reaction mixture preferably has a threshold weight percentage of at least 80% wt of the final product, and when the threshold weight percentage is reached or thereafter, the reaction mixture is discharged from the reactor module (20), and thereafter, preferably carbon dioxide, alcohol, or at least one other substance is separated from the organic carbonate as the final product.

9. The method according to claim 8, characterized in that, after or during discharge, carbon dioxide is separated from the reaction mixture, and / or alcohol and / or other substances are separated from the reaction mixture, particularly preferably by distillation and / or by at least one membrane.

10. The method according to claim 8 or 9, characterized in that after discharge, carbon dioxide and alcohol are sent to a reactor to carry out a further catalytic reaction.

11. The method according to any one of claims 1 to 10, characterized in that, during the catalytic reaction, a pressure different from the pressure of the reaction mixture is set on the membrane (21) side opposite to the reaction mixture by less than 10 bar, preferably less than 6 bar.

12. The method according to any one of claims 1 to 11, characterized in that a sweep gas flows on the membrane (21) side opposite to the reaction mixture, and the sweep gas is preferably carbon dioxide.

13. The method according to any one of claims 1 to 12, characterized in that, prior to the catalytic reaction, the catalyst is immobilized on a molecular sieve, preferably by coating the molecular sieve with a cerium salt, particularly preferably a cerium halogen salt such as cerium chloride and / or cerium(III) nitrate, and then the molecular sieve is calcined.

14. The method according to any one of claims 1 to 13, characterized in that water is separated via the membrane (21) immediately after its generation in the catalytic reaction.

15. A reactor for producing organic carbonates, particularly diethyl carbonate, wherein the reactor has at least one reactor module (20), the reactor module (20) has a reaction chamber (4), and the reaction chamber (4) is separated from a discharge chamber (10) for discharging water from the reaction chamber (4) through at least one inorganic membrane (21) and / or at least one hybrid membrane (21), wherein a catalyst is placed in the reaction chamber (4), and the catalyst is cerium oxide (CeO2). ２ ), ZrO ２ ,CrO ２ , Fe, Cu, Mg, Ni, SiO ２ Al ２ O ３ , TiO, MoO, BiO, ZnO, Ta ２ O ５ , Nb ２ O ５ A reactor characterized by containing at least one substance from among, or an alloy containing copper and nickel.

16. The reactor according to claim 15, characterized in that the film (20) has a carbon film and / or a ceramic film, particularly preferably a zeolite film, and / or the film has at least one layer that is at least mostly inorganic and / or at least one layer that is at least mostly organic.

17. The reactor according to claim 15 or 16, wherein the reactor has at least one carbon dioxide source and at least one alcohol source (ROH), and R is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably ethyl alcohol.

18. The reactor according to any one of claims 15 to 17, characterized in that the reactor has at least one circuit (22), at least one supply pump transports a mixture of liquid and / or gas along the circuit (22), the reactor module (20) is part of the circuit (22), and preferably the carbon dioxide supply source and the alcohol supply source are fluidly connected to the circuit (22).

19. The reactor according to claim 18, characterized in that the circuit (22) has a plurality of reactor modules (20) connected in parallel with each other.

20. The reactor according to any one of claims 15 to 19, characterized in that the membrane (21) is implemented as at least one membrane tube (7) and at least a portion of the discharge chamber is located inside it.

21. The reactor according to any one of claims 15 to 20, characterized in that the membrane (21) has a selectivity α for at least 100 units of water at a temperature of 80°C and a pressure of 5 bar, and / or has a selectivity α for at least 100 units of water at a temperature of 100°C and a pressure of 10 bar.

22. The reactor according to any one of claims 18 to 21, characterized in that the circuit (22) has at least one temperature control source for adjusting the temperature of the mixture in the circuit (22).

23. The reactor according to any one of claims 18 to 22, characterized in that the circuit (22) has at least one discharge channel (28) coming out of the circuit (22) for discharging the final product.

24. The reactor according to any one of claims 15 to 23, characterized in that the reactor module (20) has an inlet (3) connected to a feed channel (29) of the circuit (22) which is fluidly connected to the reaction chamber (4), and an outlet (5) which is preferably located at opposite ends of the reaction chamber (4) and connected to a retaining fluid channel (30) of the circuit (22).

25. The reactor according to any one of claims 15 to 24, characterized in that at least one membrane tube (7) protrudes into the reaction chamber (4) and preferably extends from one end of the reaction chamber (4) to the other end of the reaction chamber (4).

26. The reactor according to claim 25, characterized in that the diaphragm tube (7) is fluidly connected to a sweep gas supply source at a first end (7a) region, and the diaphragm tube (7) is fluidly connected to a water discharge channel (32) for discharging water at a second end (7b) region.

27. The reactor according to claim 26, characterized in that the first end (7a) is closed, and the fluid connection to the sweep gas supply source is made by an immersion tube (11) protruding into the membrane tube (7) via the second end (7b).

28. The reactor according to any one of claims 25 to 27, characterized in that at least five, preferably six, membrane tubes (7) are arranged within the reactor module (20).

29. The reactor according to any one of claims 15 to 28, characterized in that the reaction chamber (4) is substantially filled with a molecular sieve and the catalyst immobilized thereon.

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