Process and reactor for the production of organic carbonates

Description

/ 20 PROCESS AND REACTOR FOR THE PRODUCTION OF ORGANIC CARBONATES

[001] The invention relates to a process for the production of organic carbonates, in particular diethyl carbonate, comprising a catalytic reaction of corresponding alcohols (ROH) with carbon dioxide, wherein R is a linear or branched chain alkyl radical with 1-6 carbon atoms, preferably an ethyl radical, and wherein the water formed during the catalytic reaction is separated by means of at least one inorganic membrane and / or at least one hybrid membrane.

[002] The invention relates to a reactor for the production of organic carbonates, in particular diethyl carbonate, wherein the reactor has at least one reactor module, and the reactor module has a reaction chamber, wherein the reaction chamber is separated by at least one inorganic membrane and / or at least one hybrid membrane from a discharge chamber for discharging water from the reaction chamber.

[003] Organic carbonates are used, among other things, as starting substances for the synthesis of plastics, medicines, veterinary drugs, pesticides, dyes, photochemicals, and as electrolytes in lithium-ion batteries. Although they are currently used mainly as raw materials in the chemical industry, they are suitable as fuels or fuel additives to reduce exhaust gas emissions. Diethyl carbonate, in particular, has proven to be particularly advantageous as a fuel additive. When added to fuel, it reduces emissions of carbon monoxide (CO), particulate matter, and smoke. When DEC is produced from renewable sources, CO2 emissions of fossil origin are also reduced. In particular, the possibility of adding it to diesel fuel, as opposed to the starting product ethanol, has great ecological and economic potential.

[004] Organic carbonates are synthesized using CO2 and Petition 870250088198, dated 09 / 29 / 2025, page 14 / 45 2 / 20 of the corresponding alcohols are used as starting substances, with the organic carbonate and water being produced during the catalytic reaction. The reaction equation for this catalytic reaction is therefore generally: □ catalystDí?DR''OH - CO2- Ό' Ό+ Hz°

[005] For example, diethyl carbonate can be produced using ethanol as the alcohol: catalyst

[006] As an end product of combustion processes, CO2 is thermodynamically stable and only reactive with high energy input. The formation of organic carbonates from CO2 and alcohol is exothermic and does not occur spontaneously at room temperature. It has been found that removing the water produced during the catalytic reaction greatly promotes the reaction. Therefore, water-binding substances (chemical water scavengers) were used to remove the water.

[007] However, this is not very practical when producing larger quantities, as the water collector must be removed from the reaction mixture and regenerated or even discarded. In addition, this can lead to contamination of the final product. These processes are therefore not suitable for the production of organic carbonates on a larger industrial scale.

[008] Wang et al., 20171 describe a process and reactor that produce diethyl carbonate at ambient pressure using a Ceo,sZro,202 catalyst. In this process, water is continuously removed through an inorganic membrane during the reaction. However, this only allows1Wang, 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, 35953600. https: / / doi.org / 10.1039 / C7GC00916J Petition 870250088198, dated 09 / 29 / 2025, page 15 / 45 / 20 a very low return of approximately 0.06%, according to the document.

[009] Document CN 112657434 A describes another process and reactor for electrochemical synthesis, which operates at slightly higher pressure and temperature. A transition metal, such as Cu, Fe, Ni, Co, or Zn, is used as a catalyst. The metal is supported on a CeO2 support, which provides mechanical support. The resulting water is separated by a polyimide membrane. For the reaction to occur, electricity must be supplied via electrodes. This requires higher energy consumption and a more complex reactor design. It has also been found that this method yields insufficient results.

[0010] In Kuenen et al., 20162, the use of a cerium oxide catalyst in combination with a PEEK-chitosan membrane—a polymeric membrane—is proposed. This presents an insufficient yield. The paper describes the direct synthesis of dimethyl carbonate from methanol and CO2 in a membrane reactor with in situ water separation. Furthermore, the data were obtained through a simulation, which means that it cannot be stated whether the presented membrane can maintain the specified selectivity in practice even at high temperatures.

[0011] The object of the invention is to provide a process and a reactor by which organic carbonates can be produced in greater quantities and with a higher yield.

[0012] According to the invention, this objective is achieved by carrying out the catalytic reaction at a temperature of at least 80°C and a pressure of at least 500 kPa (5 bar), and by the fact that the catalyst comprises at least one of the following substances: cerium oxide2Kuenen, HJ, Mengers, HJ, van der Ham, AGJ, & Kiss, AA (2016). Novel Process for Conversion of CO2 to Dimethyl Carbonate using Catalytic Membrane Reactors. No. 26th 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 Petition 870250088198, dated 09 / 29 / 2025, p. 16 / 45 / 20 (CeO2), ZrO2, CrÜ2, Fe, Cu, Mg, Ni, S1O2, Al2O3, TiO, MoO, BiO, ZnO, Ta2Ü5, Nb2O5 or an alloy comprising copper and nickel.

[0013] It is also solved by placing a catalyst in the reaction chamber and by the fact that the catalyst comprises at least one of the following substances: cerium oxide (CeO2), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5 or an alloy comprising copper and nickel.

[0014] The specified metals, iron, copper, magnesium and / or nickel (Fe, Cu, Mg and / or Ni), are preferably part of the catalyst in metallic form, but may also be present in other forms, for example, in the form of a salt, oxide or organic compound.

[0015] Preferably, the catalyst is at least partially immobilized in a support material. This material can be, for example, activated carbon. This is particularly advantageous if the catalyst comprises metals such as Fe, Cu, Mg and / or Ni. It can be provided that the support material is connected to the membrane and / or forms part of the membrane. For example, at least one layer comprising support material and catalyst can be arranged on the membrane, wherein this membrane is preferably permeable to water and / or porous. This ensures that the reaction occurs in the immediate vicinity of the membrane.

[0016] Inorganic and hybrid membranes have proven to be particularly well-suited for use at higher pressures and temperatures. Even under these conditions, they exhibit high selectivity for water and can separate large quantities of water from the reaction chamber. Organic membranes can swell under certain circumstances, becoming increasingly impermeable to water. This can be avoided by using inorganic or hybrid membranes.

[0017] The membrane is permeable to water. Preferably, it is essentially impermeable or at least more impermeable to substances. Petition 870250088198, dated 09 / 29 / 2025, p. 17 / 45 / 20 starting point, that is, CO2 and / or alcohol, rather than water, and / or essentially impermeable or at least more impermeable to the final product, that is, organic carbonate, than water. In this way, the water produced can be selectively removed from the space where the reaction occurs, thus shifting the reaction equilibrium towards the organic carbonate side.

[0018] The membrane may have multiple layers with different materials or properties. Multiple membranes may separate water in parallel to each other, or multiple membranes may be arranged in parallel to each other between the reaction chamber and the separation chamber. “In parallel to each other” does not refer to the spatial alignment of the membrane surfaces relative to each other, but rather to the fact that the two membranes are not arranged one behind the other between the reaction chamber and the separation chamber, but rather that the separation of water occurs in membranes parallel to each other.

[0019] In general, membranes can be divided into three different materials: organic, inorganic, and a combination of the two (hybrids).

[0020] Organic polymer membranes are generally widely used in membrane technology because they are comparatively inexpensive and, thanks to the choice of polymers and the easily controllable manufacturing process, membrane specifications can be more easily adapted to customer requirements. However, polymer membranes tend to swell at elevated temperatures, which are necessary in our process, significantly reducing selectivity. Polymer-based pervaporation membranes presented in the literature are described for temperatures up to 60°C. However, since the process according to the invention requires temperatures >100°C, these membranes no longer achieve sufficient selectivity at elevated temperatures. Individual manufacturers present special experimental membranes for up to 110°C, but these exhibit significantly worse properties. Petition 870250088198, dated 09 / 29 / 2025, page 18 / 45 / 20 Other classic high-temperature membrane materials, such as polyimide, do not offer sufficient performance (selectivity).

[0021] Inorganic membranes are generally manufactured from a ceramic or zeolite material, which makes them suitable for higher temperatures or more aggressive environments. Compared to polymeric membranes, their manufacture is more complex and the possibilities for adapting specifications to customer requirements are less pronounced. In addition, inorganic membranes are more expensive and more susceptible to mechanical stress.

[0022] There are also so-called hybrid membranes, which comprise both organic and inorganic materials.

[0023] Preferably, a membrane, particularly preferably a hybrid membrane, has at least one predominantly inorganic layer and / or at least one predominantly organic layer. The at least predominantly inorganic layer may comprise materials such as at least one ceramic (for example, oxide ceramic and / or based on aluminum oxide, zirconium oxide and / or silicon oxide), carbide and / or zeolite. The at least predominantly organic layer may comprise materials such as PVA (polyvinyl alcohol).

[0024] It can be provided that the membrane, preferably a hybrid membrane, has at least one predominantly inorganic support layer, preferably comprising at least one ceramic, and / or that the membrane has at least one additional layer, preferably comprising at least one organic material, particularly preferably a polymeric material. Preferably, the additional layer has a higher selectivity towards water than the support layer.

[0025] The combination of the inorganic support and the organic layer Petition 870250088198, dated 09 / 29 / 2025, page 19 / 45 / 20 minimizes the swelling of organic material, which means that good selectivity results can be expected even at high temperatures.

[0026] The membrane preferably comprises at least one metal carbide-polymer membrane. These membranes exhibit particularly good temperature stability.

[0027] It can be predicted that the hybrid membrane will have at least one single layer comprising organic and inorganic materials. A single layer refers to a layer that cannot be divided into different sublayers depending on its materials. It can be predicted that the organic and inorganic materials will be mixed together. Such membranes are sometimes also referred to as mixed matrix membranes.

[0028] It can be foreseen that the hybrid membrane has at least one layer comprising an organic matrix in which the inorganic material is arranged, preferably particles and / or preferably the catalyst and / or adsorbent.

[0029] Other examples of membrane materials can be found in Vane et al.3.

[0030] Surprisingly, it was found that particularly high yields can be achieved when the specified substances are used as catalysts and higher temperature and pressure are adjusted. There is no need for an energy source, as is required for the electrochemical reduction of CO2 using transition metals. A catalyst containing cerium oxide (CeO2) proved to be particularly efficient. This catalyst resulted in particularly high yields.

[0031] Surprisingly, it was found that a higher temperature, of at least 80°C, has a positive effect on the yield and a3Vane 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. Petition 870250088198, dated 09 / 29 / 2025, page 20 / 45 / 20 reaction rate, even if the reaction is exothermic, that is, it releases heat.

[0032] The reaction chamber of the reactor module is the space in which the catalyst is located and to which the starting substances are fed, so that a catalytic reaction can occur. It is essential that the pressure and temperature in this reaction chamber correspond to the specified values ​​so that the reaction proceeds efficiently and as completely as possible.

[0033] The discharge chamber is preferably catalyst-free and serves to discharge the water that is discharged from the reaction chamber through the membrane into the discharge chamber. The water produced by the reaction penetrates the membrane and separates in the discharge chamber, where it can be discharged, for example, through a water outlet, or stored in a water reservoir.

[0034] It is preferably provided that the membrane delimits the reaction chamber on at least one side. It can therefore be provided that the catalyst and the membrane are arranged side by side. In this way, the water produced can be removed through the membrane immediately after it is produced. This applies both to the process according to the invention and to the reactor according to the invention.

[0035] Preferably, the pressure in the discharge chamber differs from the pressure in the reaction chamber by less than 600 kPa (6 bar). This avoids excessive pressure on the membrane.

[0036] The catalytic reaction can be carried out continuously or discontinuously.

[0037] A reactor for the production of organic carbonates, in particular diethyl carbonate, may also be advantageous, wherein the reactor has at least one reactor module, and the reactor module has a reaction chamber which is separated from a discharge chamber for water discharge from the reaction chamber by at least one organic membrane, Petition 870250088198, dated 09 / 29 / 2025, page 21 / 45 / 20 inorganic and / or hybrid, in which a catalyst, preferably immobilized on a molecular sieve or similar support materials, such as at least one polymer, is arranged in the reaction chamber and the catalyst comprises at least one of the following substances: cerium oxide (CeO2), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, A2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5 or an alloy comprising copper and nickel.

[0038] Thus, a process for the production of organic carbonates, in particular diethyl carbonate, may also be advantageous, comprising a catalytic reaction of corresponding alcohols (ROH) with carbon dioxide, wherein R is a linear or branched-chain alkyl radical with 1-6 carbon atoms, preferably ethyl alcohol, wherein the water produced during the catalytic reaction is separated by means of at least one organic or inorganic membrane and / or hybrid membrane, and wherein the catalyst comprises, having been immobilized on a molecular sieve or similar support materials before carrying out the catalytic reaction, and by the fact that the catalytic reaction is carried out at a temperature of at least 80°C and at a pressure of at least 500 kPa (5 bar), and by the fact that the catalyst comprises at least one of the following substances: cerium oxide (CeO2), ZrO2, CrO2, activated carbon (Fe, Cu, Mg, Ni), SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5,Nb2O5 or an alloy comprising copper and nickel.

[0039] The embodiments described in the last two paragraphs are particularly advantageous because they enable effective implementation in a particularly simple manner. They can be combined with all the special features and embodiments described in this descriptive report or in the claims. By arranging the catalyst on a molecular sieve or similar support materials, a particularly large surface area is obtained, which is particularly useful for accelerating the catalytic process. The arrangement on a molecular sieve in combination with the membrane Petition 870250088198, dated 09 / 29 / 2025, page 22 / 45 / 20 is particularly advantageous because complex membrane shapes, which offer the maximum possible membrane surface area for water drainage and give the reaction spaces an angled spatial shape, can be combined particularly effectively with the largest possible amount of catalyst. Despite the complex and angled spatial structure of the reaction space, it can be easily and compactly filled with the molecular sieve, which, thanks to its granular form, still manages to fill the space well. Molecular sieves are generally available in granular and free-flowing form, such as granules or pellets. This allows a particularly large membrane surface area to be combined with a particularly large catalyst surface area in a confined space, resulting in a synergistic improvement in yield.Furthermore, applying it to the support material has the advantage that it does not become loose in the reaction chamber, which can lead to blockages.

[0040] It is particularly advantageous if the reaction is carried out at least at 100°C, preferably at least at 120°C and particularly preferably between 110°C and 150°C, and / or that the reaction is carried out at a pressure of at least 1000 kPa (10 bar), preferably at a pressure above 1200 kPa (12 bar) and / or above 1500 kPa (15 bar), and particularly preferably between 2000 kPa and 4000 kPa (20 bar and 40 bar). As explained above, these temperature and pressure ranges allow for particularly high yields, although this initially seems paradoxical due to the exothermic nature of the reaction. In particular, a particularly high yield was achieved at a temperature between 110°C and 150°C and / or at a pressure above 12 bar, but especially at a pressure between 20 bar and 40 bar.

[0041] In a preferred embodiment, the separation is provided to be carried out through the membrane by means of membrane pervaporation. Petition 870250088198, dated 09 / 29 / 2025, page 23 / 45 / 20 and / or vapor permeation. This allows for a particularly efficient separation of water, especially at higher pressures and temperatures. Thus, it can also be foreseen that the membrane is designed to separate water by means of membrane pervaporation and / or vapor permeation.

[0042] It is particularly advantageous if the separation is carried out using at least one carbon membrane and / or at least one ceramic membrane, particularly preferably at least one zeolite membrane. Such membranes, in particular zeolite membranes, have been found to exhibit good selectivity for water despite high pressure and high temperatures and remain stable for long periods of time. The same applies if the membrane is intended to comprise a carbon membrane and / or a ceramic membrane, particularly preferably a zeolite membrane.

[0043] It is also advantageous if the catalytic reaction is carried out in at least one reactor module in which the catalyst is located. This enables a compact and controlled reaction process within the reactor module. The reactor module may have one or more reaction chambers in which the catalyst is located and in which the catalytic reaction can occur. It is particularly advantageous if the reaction chamber is separated from a discharge chamber for water discharge from the reaction chamber by at least one inorganic and / or hybrid membrane. In this way, water can be separated immediately after being produced during the catalytic reaction. This minimizes the residence time of water in the catalyst.

[0044] In this sense, it is also advantageous if the reactor has at least one source of carbon dioxide and at least one source of alcohol (ROH), where R is a linear or branched chain alkyl radical with 1-6 carbon atoms, preferably ethyl alcohol. These sources can be, for example, storage media for the substances, Petition 870250088198, dated 09 / 29 / 2025, page 24 / 45 / 20, that is, a CO2 cylinder or a container with alcohol. It is also possible that the source itself produces the substance directly; for example, the carbon dioxide source may be an internal combustion engine that produces carbon dioxide by burning fuel. Other sources of carbon dioxide may be facilities that release carbon dioxide biologically, for example through fermentation, or chemical plants. A facility for extracting carbon dioxide directly from ambient air (direct air capture) is also possible.

[0045] It is particularly advantageous if the reaction mixture is circulated through the reactor module during the catalytic reaction. In this way, the mixture of starting substances and final product is constantly mixed, and the catalyst is always supplied with starting substances and the membrane is always supplied with water, in order to achieve an efficient reaction process. In this sense, it is also advantageous if the reactor is provided with at least one circuit with at least one feed pump to transport a liquid and / or gaseous mixture along the circuit, that the reactor module is part of the circuit and that, preferably, the carbon dioxide source and the alcohol source are connected to the circuit in a flow-connected manner.

[0046] To achieve a particularly efficient conversion, it can be foreseen that, during the catalytic reaction, the reaction mixture in the circuit is conducted through several reactor modules connected in parallel. The parallel connection of the reactor modules allows the amount of starting substances converted to be further increased. This is particularly advantageous in a batch process. The same applies if the circuit has several reactor modules connected in parallel. Alternatively, several reactor modules can also be connected in series. This allows a higher concentration to be achieved.

[0047] It can also be predicted that several circuits will be Petition 870250088198, dated 09 / 29 / 2025, page 25 / 45 / 20 connected in series, wherein at least one first and one second circuit each has at least one reactor module. In other words, it can be foreseen that the reaction mixture, after being conducted through a first circuit, is at least partially conducted through a second circuit, wherein the reaction mixture is conducted through at least one additional reactor module during its passage through the second circuit. It can be foreseen that different reaction equilibria are set in the circuits. This can be particularly useful in the case of continuous operation of the process.

[0048] Preferably, it is provided that the catalytic reaction is carried out until the reaction mixture has a limit mass fraction of final product, preferably of at least 80% by weight, and that, upon reaching or after reaching the limit mass fraction, the reaction mixture is discharged from the reactor module (20) and that, after discharge, preferably carbon dioxide, alcohol or at least one other substance is separated from the organic carbonate as the final product. This batch reaction control rapidly achieves a high degree of conversion. The reaction mixture can be circulated until the limit weight fraction is reached.In this regard, it may also be advantageous if, after or during discharge, the carbon dioxide is separated from the reaction mixture, preferably by means of a droplet separator, and / or if the alcohol and / or other substances are separated from the reaction mixture, particularly preferably by means of distillation and / or by means of at least one membrane. Thus, it is also advantageous if the circuit is designed to have at least one discharge channel leading out of the circuit for discharge of the final product and if the discharge channel preferably comprises at least one capacitor and / or at least one droplet separator and, particularly preferably, a carbon dioxide return channel for returning the carbon dioxide from the droplet separator to the circuit. Petition 870250088198, dated 09 / 29 / 2025, page 26 / 45 / 20

[0049] The separated substance or substances can be returned to the circuit. It can therefore be provided that at least one return channel is provided for the respective substance for return to the circuit. The substance, i.e., carbon dioxide or alcohol, can be pre-treated before being returned, for example, compressed, heated or cooled, or purified.

[0050] It is also advantageous if, after removal, the carbon dioxide and alcohol are fed back into the reactor and a further catalytic reaction is carried out. This allows a new reaction to be initiated.

[0051] To avoid excessive stress on the membrane, it can be provided that, during the catalytic reaction, a pressure is set on the side of the membrane facing away from the reaction mixture that differs from the pressure of the reaction mixture by less than 1000 kPa (10 bar), preferably by less than 6000 kPa (6 bar).

[0052] It is also advantageous if a carrier gas flows along the side of the membrane facing away from the reaction mixture, wherein the carrier gas is preferably carbon dioxide. The flow of the carrier gas drives the water exiting the membrane away from the membrane surface, which improves water separation. The pressure on this side of the membrane can be adjusted by means of the carrier gas. Alternatively, nitrogen (N2), ethanol vapor or gas mixtures, preferably gas mixtures of the aforementioned gases, such as a mixture of Cu2-ethanol vapor, can also be used as carrier gas.

[0053] It is particularly advantageous if, prior to the catalytic reaction, the catalyst is immobilized on a molecular sieve and, preferably, a cerium salt, particularly preferably a cerium halide salt, such as cerium chloride and / or cerium(III) nitrate, is applied to the molecular sieve and the molecular sieve is then calcined. This achieves a particularly large catalyst surface area, as described above. The same applies if the reaction chamber is expected to be essentially Petition 870250088198, dated 29 / 09 / 2025, p. 27 / 45 / 20 filled with a molecular sieve and with the catalyst immobilized on it.

[0054] Preferably, the membrane is designed as at least one membrane tube, within which at least part of the discharge chamber is located. The tube-shaped design allows for efficient removal of water by means of carrier gas. Thus, it can also be provided that the water produced during the catalytic reaction is separated by means of at least one membrane designed as at least one membrane tube.

[0055] It is particularly advantageous if the membrane has an α selectivity for water of at least 100 at a temperature of 80°C and a pressure of 500 kPa (5 bar) and / or has an α selectivity for water of at least 100 at a temperature of 100°C and a pressure of 1000 kPa (10 bar). This allows the water to be separated in the purest possible form. A selectivity of 100 for water means that the membrane allows only 1 part of ethanol to pass through 100 parts of water.

[0056] In addition, to adjust the temperature of the catalytic reaction, the circuit can be designed so that it has at least one temperature control source to adjust the temperature of the mixture in the circuit and / or the temperature of the mixture in the circuit is adjusted by means of at least one temperature control source.

[0057] In a preferred embodiment, the reactor module is provided to have an inlet connected by flow to the reaction chamber, which is connected to a feed channel of the circuit, and an outlet, preferably located at the opposite end of the reaction chamber, which is connected to a retentate channel of the circuit. The feed channel and the retentate channel are also connected directly or indirectly to each other, in addition to the connection through the reactor module, so that a circuit is created.

[0058] It is particularly advantageous if at least one pipe of Petition 870250088198, dated 09 / 29 / 2025, page 28 / 45 / 20 membrane projecting into the reaction chamber and preferably extending from one end of the reaction chamber to the other end of the reaction chamber. In this way, water can be removed from the reaction chamber along its entire length, and a particularly large amount of starting substances is converted into organic carbonate throughout the reaction chamber due to the small amount of water.

[0059] It is also advantageous if the membrane tube is flow-connected to a carrier gas source in the area of ​​a first end and the membrane tube is flow-connected to a water discharge channel for water discharge in the area of ​​a second end. This achieves particularly efficient water removal.

[0060] In this sense, it can be foreseen that the first end is closed and the flow connection to the carrier gas source is made by means of an immersion tube that projects into the membrane tube through the second end. This allows the connections for the carrier gas to be arranged on one side of the reaction chamber. In addition, this makes it possible to use industrially manufactured membrane tubes with one closed end.

[0061] For efficient water separation, the water discharge channel may have a droplet separator to separate the carrier gas, preferably a condenser upstream of the droplet separator and / or a carrier gas return line to return the recovered carrier gas to the membrane tube.

[0062] The carrier gas can be carbon dioxide, for example. Even if some of it enters the reaction chamber through the membrane, it would not contaminate the mixture there. Alternatively, another gas, such as nitrogen (N2), ethanol vapor, or mixtures of gases, preferably mixtures of the gases mentioned, such as a CO2-ethanol vapor mixture, can be used. Petition 870250088198, dated 09 / 29 / 2025, page 29 / 45 / 20

[0063] Water separation is further improved if at least five, preferably six or seven membrane tubes are arranged in the reactor module.

[0064] The invention is described below with reference to non-limiting embodiments of the invention shown in the figures, in which: Figure 1a shows a reactor module according to the invention for installation in a reactor according to the invention and for carrying out a process according to the invention in a longitudinal section; Figure 1b shows a section through the reactor module of Figure 1a along line AA; Figure 2 shows a flow diagram of a reactor according to the invention, which uses a process according to the invention, in a first embodiment.

[0065] Reactor module 1 shown in Figure 1a and Figure 1b has an elongated, essentially cylindrical shape. An inlet area 2 is located at one end, which has a connection 2a for connection to a feed channel. This supplies the reactor module with carbon dioxide and alcohol. Inlet area 2 is connected via an inlet 3 to a first end 4a of the reaction chamber 4, which is filled with pellet-shaped molecular sieve (not shown) and with the catalyst calcined in it, so that the starting substances can be converted into organic carbonate by the catalyst in the reaction chamber 4. The reaction chamber 4 extends over a large part of reactor module 1; for better visualization, reactor module 1 is shown interrupted at the area of ​​reaction chamber 4.

[0066] The reaction chamber 4 is flow-connected to an outlet area 6 via an outlet 5 at its opposite end, the second end 4b. The outlet area 6 has a connection 6a for connection to a retentate channel. This allows the retentate, which comprises the product Petition 870250088198, dated 09 / 29 / 2025, page 30 / 45 / 20 final, optionally mixed with the unconverted starting substances, be removed from reaction chamber 4.

[0067] A total of seven membrane tubes 7 extend along the longitudinal axis of the reaction chamber 4, passing through an end wall 8 from the outlet area 6 to the outlet area 6 and continuing into the reaction chamber 4 to the first end 4a. The end wall 8 is rigidly connected to the membrane tubes 7. The membrane tubes 7 terminate in a water collection area 9, which is located behind the end wall 9. The outer walls of the membrane tubes 7 therefore face the reaction chamber 4, while the inner walls of the membrane tubes 7 face a discharge chamber 10, which is formed from the internal spaces of the membrane tubes 7 and is free of catalyst.

[0068] At a second end 7b of the membrane tubes 7, these are open and in flow communication with the water collection area 9. The water entering the discharge chamber 10 from the reaction chamber 4 through the membrane tubes 7 can thus be collected in the water collection area 9 and discharged into a discharge channel through a connection 9a from the water collection area 9.

[0069] The membrane tubes 7 are closed at a first end 7a, which is the end facing the first end 4a of the reaction chamber 4. Immersion tubes 11 are inserted into the membrane tubes 7 through the second end 7b, extending to the first end 7a and being open there. This allows the carrier gas to be fed into the discharge chamber 10 through the immersion tubes 11 in the area of ​​the first end 7a. The immersion tubes 11 confine the discharge chamber 10 to the narrow area between the outside of the immersion tubes 11 and the inside of the membrane tubes 7.

[0070] Immersion tubes 11 extend from the second end Petition 870250088198, dated 09 / 29 / 2025, p. 31 / 45 / 20 7b through the water collection area 9 and through an additional end wall 12 of the reactor module 1, this end wall 12 also being rigidly connected to the immersion tubes 11. In addition to the end wall 12, the immersion tubes 11 can be connected to a carrier gas source.

[0071] Figure 2 shows a flow diagram explaining one embodiment of a reactor according to the invention in more detail. The reactor has a reactor module 20 with a membrane 21 separating a reaction chamber 4 from a discharge chamber 10. The reaction chamber 4 is part of a circuit 22 that has a circulation pump 23 that moves its fluid in one direction. The circuit 22 may have channels, such as tubes, to conduct the fluid. The membrane 21 comprises at least one inorganic membrane and / or at least one hybrid membrane.

[0072] The reaction chamber is connected, via an inlet, to a feed channel 29 of the circuit 22 downstream of the circuit pump 23 and, via an outlet, to a retentate channel 30 upstream of the circuit pump 23. In this sense, “connected” refers to flow connections. The circuit pump 23 therefore acts as a feed pump.

[0073] Figure 2 shows only one reactor module 20. However, as already explained, it can also be predicted that the feed channel 29 branches upstream of the reactor module and feeds several reactor modules 20 in parallel. Thus, the retentate channel 30 would branch correspondingly to collect the reaction mixture from the reactor modules and unite it upstream of the circulation pump 23 in a single channel.

[0074] A feed line 24 for ethanol is also connected to circuit 22, through which ethanol is fed from an ethanol tank 25 and, via a feed pump, to the circuit. Preferably, the feed line 24 is arranged downstream of the circulation pump 23 and upstream of the reactor module 20, as shown. Petition 870250088198, dated 09 / 29 / 2025, page 32 / 45 / 20 in this modality.

[0075] A carbon dioxide (CO2) feed line 26 is also connected to the circuit 22, through which CO2 from a carbon dioxide tank 27 and, optionally, an additional feed pump, is fed into the circuit. Preferably, the feed line 26 is arranged downstream of the circuit pump 23 and upstream of the reactor module 20, as shown in this embodiment.

[0076] Circuit 22 is also connected to a discharge channel 28 between reaction chamber 4 and circuit pump 23, through which the retentate can be discharged into a retentate tank 31.

[0077] The discharge chamber 10 is connected by means of an additional power line 35 to a carbon dioxide source, preferably the same carbon dioxide tank 27. Thus, the CO2 in the discharge chamber 10 acts as a carrier gas and drives the water away from the membrane 21.

[0078] The discharge chamber 10 is connected to a water discharge channel 32, through which water can be discharged from the discharge chamber 10 and conveyed to a water tank 34. The water discharge channel 32 preferably has a condenser 33, through which the water is condensed before being conveyed to the water tank 34.

[0079] The reactor module 20 is preferably temperature controlled, particularly preferably by means of a temperature control fluid, such as oil, which is conducted to and from the reactor module 20 by means of temperature control channels 36. Petition 870250088198, dated 09 / 29 / 2025, pp. 33 / 45

Claims

1 / 6 CLAIMS 1. Process for the production of organic carbonates, in particular diethyl carbonate, comprising a catalytic reaction of corresponding alcohols (ROH) with carbon dioxide, wherein R is a linear or branched chain alkyl radical with 1-6 carbon atoms, preferably an ethyl radical, and wherein the water formed during the catalytic reaction is separated by means of at least one inorganic membrane (21) and / or at least one hybrid membrane (21), characterized in that the catalytic reaction is carried out at a temperature of at least 80°C and at a pressure of at least 500 kPa (5 bar), and in that the catalyst comprises at least one of the following substances: cerium oxide (CeO2), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, Al2O3, TiO, MoO, BiO, ZnO, Ta2O5, Nb2O5 or a an alloy comprising copper and nickel.

2. Process according to claim 1, characterized in that the reaction is carried out at at least 100°C, preferably at least 120°C and particularly preferably between 110°C and 150°C, and / or in that the reaction is carried out at at least 1000 kPa (10 bar), preferably at a pressure between 2000 kPa and 4000 kPa (20 bar and 40 bar).

3. Process according to claim 1 or 2, characterized in that the separation by means of the membrane (31) is carried out by means of membrane pervaporation and / or vapor permeation.

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

5. Process according to any of claims 1 Petition 870250088198, dated 09 / 29 / 2025, page 34 / 45 2 / 6 to 4, characterized in that the catalytic reaction is carried out in at least one reactor module (20) in which the catalyst is disposed and in that, preferably, the reaction chamber (4) is separated from a discharge chamber (10) for water discharge from the reaction chamber (4) by at least one inorganic membrane (21) and / or at least one hybrid membrane (21).

6. Process according to claim 5, characterized in that, during the catalytic reaction, the reaction mixture is conducted in the circuit (22) through the reactor module (20).

7. Process according to claim 6, characterized in that, during the catalytic reaction, the reaction mixture is conducted in the circuit (22) through several reactor modules (20) connected in parallel.

8. Process according to any one of claims 1 to 7, characterized in that the catalytic reaction is carried out until the reaction mixture has a limiting mass fraction of final product, preferably of at least 80% by weight, and in that, upon reaching or after reaching the limiting mass fraction, the reaction mixture is discharged from the reactor module (20) and in that, after discharge, preferably carbon dioxide, alcohol or at least one other substance is separated from the organic carbonate as final product.

9. Process 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. Process according to claim 8 or 9, characterized in that, after removal, carbon dioxide and alcohol are fed to the reactor and a further catalytic reaction is carried out. Petition 870250088198, dated 29 / 09 / 2025, pp. 35 / 45 3 / 6 11. Process according to any one of claims 1 to 10, characterized in that, during the catalytic reaction, a pressure is set on the side of the membrane (21) facing away from the reaction mixture which differs from the pressure of the reaction mixture by less than 1000 kPa (10 bar), preferably by less than 6000 kPa (6 bar).

12. Process according to any one of claims 1 to 11, characterized in that a carrier gas flows along the side of the membrane (21) facing away from the reaction mixture, wherein the carrier gas is preferably carbon dioxide.

13. Process 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 and, preferably, a cerium salt, particularly preferably a cerium halide salt, such as cerium chloride and / or cerium(III) nitrate, is applied to the molecular sieve and the molecular sieve is then calcined.

14. Process according to any one of claims 1 to 13, characterized in that water is separated by means of the membrane (21) immediately after being formed during the catalytic reaction.

15. Reactor for the production of organic carbonates, in particular diethyl carbonate, wherein the reactor comprises at least one reactor module (20), and the reactor module (20) comprises a reaction chamber (4), wherein the reaction chamber (4) is separated from a discharge chamber (10) for water discharge from the reaction chamber (4) by at least one inorganic membrane (21) and / or at least one hybrid membrane (21), characterized in that a catalyst is disposed in the reaction chamber (4) and in that the catalyst comprises at least one of the following substances: cerium oxide (CeOi), ZrO2, CrO2, Fe, Cu, Mg, Ni, SiO2, Al2O3, TiO, MoO, BiO, ZnO, TaiOs, Nb2O5 or an alloy comprising copper and nickel. Petition 870250088198, dated 29 / 09 / 2025, p. 36 / 45 4 / 6 16. Reactor according to claim 15, characterized in that the membrane (20) comprises a carbon membrane and / or a ceramic membrane, particularly preferably a zeolite membrane, and / or in that the membrane has at least one predominantly inorganic layer and / or at least one predominantly organic layer.

17. Reactor according to claim 15 or 16, characterized in that the reactor has at least one source of carbon dioxide and at least one source of alcohol (ROH), wherein R is a linear or branched chain alkyl radical with 1-6 carbon atoms, preferably ethyl alcohol.

18. Reactor according to any one of claims 15 to 17, characterized in that the reactor has at least one circuit (22) with at least one feed pump for transporting a liquid and / or gaseous mixture along the circuit (22), in that the reactor module (20) is part of the circuit (22) and in that, preferably, the carbon dioxide source and the alcohol source are connected to the circuit (22) in a flow-connected manner.

19. Reactor according to claim 18, characterized in that the circuit (22) has several reactor modules (20) that are connected in parallel to each other.

20. Reactor according to any one of claims 15 to 19, characterized in that the membrane (21) is designed as at least one membrane tube (7), within which at least part of the discharge chamber is located.

21. Reactor according to any one of claims 15 to 20, characterized in that the membrane (21) has an α selectivity for water of at least 100 at a temperature of 80°C and a pressure of 500 kPa (5 bar) and / or has an α selectivity for water of at least 100 Petition 870250088198, dated 09 / 29 / 2025, page 37 / 45 5 / 6 at a temperature of 100°C and a pressure of 1000 kPa (10 bar).

22. 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. Reactor according to any one of claims 18 to 22, characterized in that the circuit (22) has at least one discharge channel (28) leading out of the circuit (22) for final product discharge.

24. Reactor according to any one of claims 15 to 23, characterized in that the reactor module (20) has an inlet (3) connected by flow to the reaction chamber (4), which is connected to a feed channel (29) of the circuit (22), and has an outlet (5) preferably disposed at the opposite end of the reaction chamber (4), which is connected to a retentate channel (30) of the circuit (22).

25. Reactor according to any one of claims 15 to 24, characterized in that at least one membrane tube (7) projects 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. Reactor according to claim 25, characterized in that the membrane tube (7) is flow-connected to a carrier gas source in the area of ​​a first end (7a) and the membrane tube (7) is flow-connected to a water discharge channel (32) for discharging water in the area of ​​a second end (7b).

27. Reactor according to claim 26, characterized in that the first end (7a) is closed and the flow connection to the carrier gas source is made by means of an immersion tube (11) projecting into the membrane tube (7) by means of the second end (7b).

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

29. 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 therein. Petition 870250088198, dated 29 / 09 / 2025, p. 39 / 45

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