Method for producing phosgene by reusing carbon dioxide from recycled useful materials

Abstract

The present invention relates to a method for producing phosgene, particularly a method for reacting phosgene with an organic amino compound to give an organic isocyanate. In this method, at least one carbon dioxide gas stream formed from the hydrolysis of an organically modified carbamate, optionally freed from secondary components, is reductively converted to carbon monoxide. The resulting carbon monoxide is reacted with chlorine in a phosgene synthesis to give phosgene. The organically modified carbamate for this method can preferably be obtained by chemical degradation of polyurethane materials after their useful life, particularly using alcohols, amines, or aminoalcohols as chemical degradation agents.

Description

[Technical Field]

[0001] The present invention relates to a process for producing phosgene, in particular a process for reacting phosgene with an organic amino compound to give an organic isocyanate, which process comprises converting at least one carbon dioxide gas stream, formed from the hydrolysis of an organic carbamate and optionally having secondary components removed, to carbon monoxide, and converting the carbon monoxide obtained in a phosgene synthesis using chlorine to phosgene. [Background technology]

[0002] Recycling carbon dioxide (hereinafter also referred to as CO2) into value chains is a contribution to sustainability. In the past, some efforts have been made to make CO2 available for the production of carbon monoxide (hereinafter also referred to as CO), for example.

[0003] EP 3744812 states that CO2 formed during the pyrolysis and combustion of useful polyurethane materials is converted to CO by reduction in CO2 electrolysis. The resulting CO2 is reacted with chlorine to give phosgene, which serves as a starting material for polyurethanes in the preparation of organic isocyanates. In particular, the CO2 obtained in combustion must be subjected to complex cleaning processes before it can be used for electrochemical CO2 reduction.

[0004] In the method for recycling CO2 into the production of isocyanate compounds according to WO 2021 / 089737, CO2 from an external source, for example from the combustion of useful polyurethane materials, is converted to CO2 using hydrogen in a reverse water gas shift reaction (RWGS reaction). Again, the CO2 needs to be cleaned in a complex manner before it can be used in the RWGS reaction.

[0005] The method according to WO 2022 / 167387 provides a further option for recycling CO2 into the production of isocyanate compounds. Here, CO2 formed in the steam reforming process and additional CO2 from a further CO2 source are recycled into the steam reforming process. The further CO2 sources mentioned are, for example, CO2 obtained in cement production or waste incineration. CO2 from these sources must likewise be cleaned in a complex manner before being used in the steam reforming process. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 3744812 [Patent Document 2] International Publication No. 2021 / 089737 [Patent Document 3] International Publication No. 2022 / 167387 Summary of the Invention

[0007] The objective of the present invention is to reduce the process complexity of prior art CO2 utilization methods in order to make these methods more economical and / or more environmentally friendly. Overall, a sustainable method for the production and recycling of polyurethane materials is provided.

[0008] The "sustainability" of a method is understood by those skilled in the art to mean that the implementation of the current method has as little impact as possible or no impact at all on impairing the ability of future generations to meet their needs, particularly with regard to the use of resources such as fossil raw materials, and in particular with regard to the preservation of living space, for example the protection of the Earth's atmosphere, in accordance with the definition of sustainability (sustainable development) put forward by the United Nations in the Brundtland Report of the World Commission on Environment and Development.

[0009] It has been found that the CO formed in the hydrolysis of organically modified carbamate compounds (especially the CO formed in the hydrolysis of organically modified carbamates obtained from the chemical degradation of polyurethane materials) has a very high purity, which can result in low levels of economic and / or environmental resource usage for reductive conversion to CO.

[0010] Therefore, the present invention firstly comprises at least the following steps: Producing a CO2 gas stream comprising at least the following steps: providing at least one organically modified carbamate; hydrolyzing the provided at least one organically modified carbamate to form at least an organic amino compound and CO2; Separating and removing the formed CO2 to obtain at least one CO2 gas stream. producing a CO gas stream by washing the CO2 gas stream, preferably by at least one washing method selected from condensation, adsorption, catalytic gas washing or gas scrubbing, to remove secondary components (in particular secondary components selected from at least one compound from the list formed by alcohols, polyethers, hydrocarbons, organic amines, water, sulfur compounds, dust, oxygen and nitrogen) to obtain washed carbon dioxide; reducing CO2 in the at least one optionally cleaned CO2 gas stream produced to carbon monoxide; synthesizing phosgene from at least the carbon monoxide and chlorine obtained by the reduction; The present invention provides a method for producing phosgene (particularly a method for preparing an organic isocyanate) by

[0011] For example, DE 19719084 A1, EP 0031538 A1, WO 2022 / 171586 A1 and WO 2022 / 128871 A1 disclose that chemical decomposition of useful polyurethane materials can provide organic amines and polyols as chemical compounds therefrom that can be reused for the production of polyurethane materials.

[0012] In this context, one approach to the physical recycling of polyurethane materials is, for example, alcoholysis or glycolysis, in which urethane groups are reacted with alcohols or glycols by transesterification or transurethane conversion, respectively.

[0013] [ka] Additionally, urethane groups can be reacted with amines to form ureylene groups.

[0014] [ka] Nowhere is a specific suitability described for the reuse of CO2-containing off-gases from the hydrolysis of organically modified carbamates or chemical decomposition processes of polyurethane materials.

[0015] In the context of the present invention, a "polyurethane material" is a polyaddition product (sometimes called a polycondensation product, although this is not entirely accurate) obtained by reacting a polyfunctional isocyanate (= the isocyanate component in the polyurethane preparation) with a polyol (= the polyol component in the polyurethane preparation). Polyurethane materials generally contain not only the polyurethane basic structure outlined above, but also other structures, such as structures with urea bonds. The presence of such structures, in addition to the polyurethane structure, that differ from the pure polyurethane base structure does not depart from the scope of the present invention. Polyurethane materials are in particular polyurethane foams obtained by reacting a polyfunctional isocyanate with a polyol in the presence of a blowing agent.

[0016] In the terms of the present invention, the term isocyanate encompasses all isocyanates known to those skilled in the art in the context of polyurethane chemistry, such as, in particular, tolylene diisocyanate (TDI; prepared from tolylene diamine, TDA), di- and polyisocyanates of the diphenylmethane series (MDI; prepared from di- and polyamines of the diphenylmethane series, MDA), pentane 1,5-diisocyanate (PDI; prepared from pentane-1,5-diamine, PDA), hexamethylene 1,6-diisocyanate (HDI; prepared from hexamethylene-1,6-diamine, HDA), isophorone diisocyanate (IPDI; prepared from isophorone diamine, IPDA) and xylylene diisocyanate (XDI; prepared from xylylene diamine, XDA). The term "isocyanate" also encompasses embodiments in which two or more different isocyanates (e.g., a mixture of MDI and TDI) are used in the production of polyurethane foam, unless otherwise indicated, for example, by the term "exactly one isocyanate." The totality of all isocyanates used in the production of polyurethane foam is referred to as the isocyanate component (of the polyurethane foam). The isocyanate component includes at least one isocyanate. Similarly, the totality of all polyols used in the production of polyurethane foam is referred to as the polyol component (of the polyurethane foam). The polyol component includes at least one polyol.

[0017] In the terms of the present invention, the term polyol encompasses all polyols known to those skilled in the art in polyurethane chemistry, such as, in particular, polyether polyols, polyester polyols, polyether ester polyols, and polyether carbonate polyols. The term "polyol" naturally encompasses embodiments in which two or more different polyols are used in the production of polyurethane foams. Thus, for example, when "polyether polyol" (or "polyester polyol," etc.) is referred to below, this term naturally encompasses embodiments in which two or more different polyether polyols (or two or more different polyester polyols, etc.) are used in the production of polyurethane materials.

[0018] The term "organically modified carbamate" as used herein refers to organic urethane compounds, including both polyurethane materials and, preferably, organically modified carbamates formed by reaction with chemical degradation agents during chemical degradation of polyurethane materials.

[0019] An "organic compound" contains at least one covalent carbon-hydrogen bond in the molecule. Thus, an organic amino compound is an organic substance that, as a chemical compound, contains at least one amino group and at least one covalent carbon-hydrogen bond in the molecule. Organically modified carbamates are defined mutatis mutandis.

[0020] According to the present invention, "chemical degradation" refers to the chemical transformation of polyurethane materials by transesterification (also called urethane transfection) or cleavage of the polyurethane polymer structure by the formation of ureylene groups (also carbonyldiimino groups, *-NH-C(=O)-NH-*).

[0021] "Chemical degradation reagent" means a reagent that enters into a chemical reaction to perform chemical degradation using a urethane bond as the reactive group of a polyurethane material.

[0022] In the context of a preferred embodiment of the method, the organically modified carbamate is provided by chemical decomposition of a polyurethane material. This means that, in the context of this embodiment, it is sufficient for the organically modified carbamate to be a direct process product of chemical decomposition of a polyurethane material. This means that when carrying out the step of providing the organically modified carbamate, it is sufficient to simply remove the organically modified carbamate from a storage container or, if delivered as a raw material, from a supply conduit. In this case, the phosgene producer, as the executor of the method of the present invention, does not carry out chemical decomposition of a polyurethane material for the production of the organically modified carbamate, but only ensures that the provided organically modified carbamate is appropriately produced by chemical decomposition by the supplier and is a process product thereof. Therefore, a preferred embodiment of the method is that the provided organically modified carbamate is obtained by at least the following method steps: providing a polyurethane material; reacting the provided polyurethane material with at least one chemical degradation reagent (particularly selected from (a) a primary or secondary organic amine, (b) an amino alcohol having a primary or secondary amino group, or (c) an alcohol having at least one hydroxyl group) to form at least one organically modified carbamate; at least one direct process product of chemical degradation of a polyurethane material, including

[0023] In principle, the provided polyurethane material can be any type of polyurethane product, i.e., polyurethane foam or polyurethane product from what are called CASE applications. The polyurethane foam can be either flexible or rigid, with flexible foam (e.g., from used mattresses, furniture cushions, or car seats) being preferred. For polyurethane products from CASE applications, polyurethane elastomers, polyurethane adhesives, and polyurethane coatings are preferred. Of all polyurethane products, flexible polyurethane foams are particularly preferred. The provided polyurethane material can be provided, for example, from polyurethane material waste from corresponding end-of-life polyurethane products (e.g., mattresses, cushions, or insulation materials).

[0024] Furthermore, with regard to the isocyanate component, polyurethane materials based on an isocyanate selected from the group consisting of tolylene diisocyanate (TDI), di- and polyisocyanates of the diphenylmethane series (MDI), pentane 1,5-diisocyanate (PDI), hexamethylene 1,6-diisocyanate (HDI), isophorone diisocyanate (IPDI), and xylylene diisocyanate (XDI), as well as mixtures of two or more of the aforementioned isocyanates, are preferred. With regard to the isocyanate component, polyurethane materials based on TDI or mixtures of TDI and MDI are particularly preferred. With regard to the isocyanate component, polyurethane materials based solely on TDI are very particularly preferred.

[0025] Furthermore, with regard to the polyol component, polyurethane materials based on polyols selected from the group consisting of polyether polyols, polyester polyols, polyether ester polyols, polyether carbonate polyols, and mixtures of two or more of the foregoing polyols are preferred.

[0026] The provision of the polyurethane material preferably includes preparatory steps for subsequent reaction with chemical decomposition reagents. These involve, in particular, mechanical comminution of the polyurethane material. Such preparatory steps are known to those skilled in the art; see, for example, the review article by Simon, Borreguero, Lucas, and Rodriguez in Waste Management 2018, 76, 147-171.

[0027] It has been found to be particularly advantageous if the provided polyurethane material is subjected to a passivation process that includes at least removing oxygen gas surrounding the polyurethane material and / or contained in the pores of the polyurethane material. Passivation is particularly desirable when the polyurethane material is in the form of a powder, granules, or foam. By passivating the provided polyurethane material prior to reaction with the chemical decomposition reagent, particularly high purity of the CO2 gas stream obtained by hydrolysis can be achieved. For example, in the case of a polyurethane material in the form of a foam, if passivation is not required, the CO2 obtained by hydrolysis will increase the concentration of N2 and especially O2, which must be removed from the CO2 gas stream with a high degree of complexity.

[0028] In a preferred embodiment, the inerting further comprises the step of supplying at least one inert gas (in particular nitrogen, carbon dioxide, argon or helium, most preferably carbon dioxide) to the polyurethane material.

[0029] The deactivation of the provided polyurethane material more preferably comprises at least the following steps: 960mbar (abs) degassing the polyurethane material by applying a first pressure of: The gas is introduced into the vessel at a first pressure of 700 mbar. (abs) a reduced pressure of less than 0.1 mbar (abs) ~100mbar (abs)The gas is removed by applying a pressure of 0.1 to the gas removal device.

[0030] After the gas has been removed, at least one inert gas (in particular nitrogen, carbon dioxide, argon or helium, most preferably carbon dioxide) is fed, preferably at 1.8 bar. (abs) A pressure of 0.15 bar, more preferably atmospheric pressure, is established.

[0031] The degassing and overall inerting practice is described in WO 2022 / 128871, which is expressly and fully incorporated herein by reference.

[0032] It is also possible in the context of a further embodiment of the present invention if the aforementioned chemical decomposition conversion is carried out by the phosgene producer itself as an integral step of a process for producing phosgene to provide an organically modified carbamate, which is then fed to hydrolysis to form CO. Accordingly, a corresponding preferred embodiment of the process is characterized in that the CO gas stream (31) is subjected to at least the following steps: providing a polyurethane material; reacting the provided polyurethane material with at least one chemical degradation reagent (particularly selected from (a) a primary or secondary organic amine, (b) an amino alcohol having a primary or secondary amino group, or (c) an alcohol having at least one hydroxyl group) to form at least one organically modified carbamate; hydrolyzing the pre-formed organically modified carbamate to form at least an organic amino compound and CO2; Separating and removing the formed CO2 to obtain at least one CO2 gas stream; The polyurethane material is characterized in that it is produced by chemical decomposition of a polyurethane material containing:

[0033] In the context of the aforementioned embodiment of the present invention, the hydrolysis step can be carried out as a separate process step and / or simultaneously in one step with the conversion of the polyurethane material, using a mixture comprising a chemical degradation reagent and also sufficient water.

[0034] It is generally preferred that the provided organically modified carbamate is formed by the reaction of the provided polyurethane material with at least one chemical decomposition agent, or is the direct process product of such a reaction, excluding oxygen. This means that the reaction is carried out in an inert gas atmosphere (particularly in a nitrogen, carbon dioxide, argon or helium atmosphere, more preferably in a carbon dioxide atmosphere). It is also preferred to remove oxygen from the chemical decomposition agent (water and chemical decomposition agent) used by inert gas saturation. In this regard, it is very particularly preferred that the provided polyurethane material is inactivated as described above.

[0035] In a preferred embodiment, providing the organically modified carbamate comprises at least the following method steps: providing a polyurethane material; reacting the provided polyurethane material with at least one chemical degradation reagent (particularly selected from (a) a primary or secondary organic amine, (b) an amino alcohol having a primary or secondary amino group, or (c) an alcohol having at least one hydroxyl group) to form a composition comprising at least one organically modified carbamate; blending the previously obtained composition with an organic solvent that is incompletely miscible with the previously used chemical decomposition reagent without prior removal of water present in the composition, and allowing it to separate into a carbamate phase (containing the organically modified carbamate) and a solvent phase; This is achieved by:

[0036] In this embodiment, the resulting carbamate phase is introduced into a hydrolysis step.

[0037] The organic solvent used must be incompletely miscible with the chemical decomposition reagent used in the chemical decomposition. This means that a miscibility gap must exist under the conditions necessary for the blending step, allowing for phase separation. The organic solvent is preferably selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and mixtures of two or more of the aforementioned organic solvents.

[0038] In the integration of chemical decomposition as a process step in a further preferred embodiment of the phosgene production according to the invention, it is particularly preferred if said reaction of polyurethane material to give said organically modified carbamate and said hydrolysis of said organically modified carbamate are carried out together in one process step.

[0039] Generally, it is preferred that the water for hydrolysis and the chemical decomposition reagent for the chemical decomposition reaction in the method of the present invention are used in superstoichiometric amounts, regardless of whether the chemical decomposition reaction occurs alone or in one step in combination with hydrolysis. This means that the water for hydrolysis is used in an amount theoretically sufficient to hydrolyze all polyurethane bonds in the provided polyurethane material, accompanied by the release of at least carbon dioxide and an organic amino compound. Similarly, the use of a superstoichiometric amount of chemical decomposition reagent means that the chemical decomposition reagent is used in an amount theoretically sufficient to convert all polyurethane bonds in the provided polyurethane material to form organically modified carbamates. Both of these usually apply when using the mass proportions of water and chemical decomposition reagent preferred in accordance with the present invention, as described below.

[0040] The chemical degradation conversion is preferably carried out so that the mass ratio of the chemical degradation reagent (total used) and water (total used) on the one hand to the provided polyurethane material on the other hand (i.e., [m(chemical degradation reagent) + m(water)] / m(polyurethane product), m = mass) is in the range of 0.5 to 2.5, more preferably 1.0 to 1.3, and the mass of water is 2.0% to 10% of the mass of the chemical degradation reagent. The quantitative values ​​for water here refer to the water added as a reagent for hydrolysis. In comparison, the amount of water resulting from the moisture present in the chemical degradation reagent and / or polyurethane material used is small. The moisture in the chemical degradation reagent used or the polyurethane material used refers to the trace amounts of moisture that can occur on an industrial scale. The mass of water here is more preferably 4.0% to 10.0%, particularly preferably 5.0% to 7.0%, of the mass of the chemical degradation reagent used.

[0041] The chemical decomposition reaction and hydrolysis can be preferably carried out as chemical decomposition of the polyurethane material using a chemical decomposition reagent and water (preferably in the presence of a catalyst) at a temperature in the range of 130°C to 220°C, wherein the mass ratio of the chemical decomposition reagent and water on the one hand to the polyurethane material on the other hand is in the range of 0.5 to 2.5, and the mass of the water is 4.0% to 10% of the mass of the polyurethane material.

[0042] In the context of the typical implementation of chemical degradation and hydrolysis in one process step, it has proven particularly advantageous not to add the water used for hydrolysis at the beginning of the reaction time, or at least not to add it at all. It has proven useful to initially mix only a small proportion of the total amount of water used, i.e., in any case only 2% to 4% of the total amount of water, with the other reactants (i.e., at least the chemical degradation reagent and polyurethane material), and then add the remaining or total amount of water over the course of the further reaction time. Water for the hydrolysis of the organically modified carbamate formed as an intermediate is added continuously or in portions at intervals so that the boiling temperature of the reaction mixture always remains within the specified range, particularly the particularly preferred range of 165°C to 185°C. The metering time for water is preferably in the range of 1.0 to 5.0 hours (depending on the boiling point of the chemical degradation reagent used). In a preferred embodiment, a mass ratio of the chemical degradation reagent (total used) and water (total used) on the one hand to the polyurethane material on the other hand, [m(chemical degradation reagent + water) / m(polyurethane material)], is used in the range of 1.1 to 1.3. If the water is added gradually as above rather than all at once, this applies to the total amount of water used.

[0043] The amount of water used in the context of typical implementation of chemical degradation and hydrolysis in one method step is preferably 5.0% to 7.0% of the mass of the chemical degradation reagent used, which is particularly applicable in conjunction with the aforementioned range of 1.0 to 1.3 for the mass ratio [m (chemical degradation reagent + water) / m (polyurethane material)]. If water is added gradually as described above rather than all at once, this also applies to the total amount of water used in this step.

[0044] In the general context of chemical decomposition and hydrolysis in one process step, it is not necessary to add all the water at the beginning. In this case, the above range of the amount of water based on the mass of the chemical decomposition reagent refers to the total amount of water added by the end of the reaction time. The same applies when the chemical decomposition reagent is added gradually.

[0045] especially,

[0046] (I) first mixing the polyurethane material with only the chemical degradation reagent or with a first amount of the chemical degradation reagent and water, and then

[0047] (II) Adding water or a second portion of water, especially only after the polyurethane material has gone into solution It is also possible.

[0048] The term "goes into solution" in this context does not necessarily imply the presence of a "true" solution in the sense of a completely homogeneous mixture. Cases may arise where a cloudy "solution" of polyurethane material is present, and this does not depart from the scope of the present invention.

[0049] In the course of carrying out the general chemical decomposition and hydrolysis in steps (I) and (II) described above, it is particularly preferred to add water or the second portion of water in step (II) continuously or in portions so that the temperature of the liquid phase in step (II) differs from the temperature of the liquid phase from step (I) by at most 20° C., preferably at most 15° C., more preferably at most 10° C., even more preferably at most 5.0° C., and very particularly preferably at most 1.0° C. This achieves that the temperature is always high enough to ensure the progress of the chemical decomposition reaction.

[0050] The implementation of chemical decomposition combined with hydrolysis in one step is described, for example, in WO 2022 / 171586 using as an example an alcohol having at least one hydroxyl group as the chemical decomposition reagent, which document is expressly and fully incorporated herein by reference.

[0051] The implementation of chemical degradation using hydrolysis as a separate step is described, for example, in U.S. Pat. No. 4,336,406 and WO 2020 / 260387, in each case using as an example an alcohol having at least one hydroxyl group as the chemical degradation reagent, which documents are expressly and fully incorporated herein by reference.

[0052] The chemical decomposition may generally be combined with hydrolysis and may be carried out in any reactor known for such purposes in the art. Particularly suitable chemical decomposition reactors are stirred tank (stirred reactors) and tubular reactors.

[0053] In a further embodiment, it is particularly preferred to use at least one catalyst to assist the chemical degradation of the polyurethane material in the reaction with the chemical degradation reagent (e.g., alone or in a single step in combination with hydrolysis). The catalyst used in this preferred embodiment is more preferably at least one compound selected from carbonates, bicarbonates, orthophosphates, monohydrogen orthophosphates, metaphosphates, hydroxides, organic amines (especially diethanolamine), organometallic compounds (especially titanium tetrabutoxide, tin octoate, or dibutyltin dilaurate), or a mixture of two or more of the aforementioned catalysts. It is very particularly preferred to use at least one metal salt selected from carbonates, bicarbonates, orthophosphates, monohydrogen orthophosphates, metaphosphates, or a mixture of two or more of the aforementioned metal salts as the catalyst.

[0054] Orthophosphates are salts of orthophosphoric acid, H3PO4, from which all protons have been removed (=PO4 3- ). Monohydrogen orthophosphate is the salt of orthophosphoric acid with two protons removed (=HPO4 2- ). Metaphosphate has the empirical formula [(PO3) - ] n where n is a natural number (in particular 3 or 4).

[0055] If a catalyst is used in the chemical decomposition step, it is preferably used in an amount such that its mass is between 0.1% and 3.5% of the mass of the provided polyurethane material.

[0056] If the catalyst is used in the form of an aqueous solution, the water used as solvent should likewise be taken into account in the quantitative figures given above for the use of water in the hydrolysis, i.e. the amount of water additionally used, if required in the hydrolysis, should be correspondingly reduced.

[0057] It is further preferred that at least one of the aforementioned catalysts is used for the hydrolysis.

[0058] In a further embodiment, it is particularly preferred to carry out the chemical degradation (e.g., alone or, preferably, in one step in combination with hydrolysis) as a reaction of the polyurethane material with at least one chemical degradation reagent selected from (a) a primary or secondary organic amine, (b) an amino alcohol having a primary or secondary amino group, or (c) an alcohol having at least one hydroxyl group.

[0059] Suitable alcohols having at least one hydroxyl group as chemical decomposition reagents are preferably at least one alcohol having at least two hydroxyl groups, and in this context, it is particularly preferred if the chemical decomposition reagent is selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methyl glycol, triethylene glycol, glycerol, 2-methylpropane-1,3-diol, or a mixture of two or more of the aforementioned alcohols.

[0060] Suitable amino alcohols having a primary or secondary amino group as chemical decomposition reagents are preferably at least one amino alcohol selected from ethanolamine, N-methylethanolamine, 3-amino-1-propanol.

[0061] The primary or secondary organic amine suitable as a chemical decomposition reagent is preferably at least one aliphatic primary or secondary organic amine. These primary or secondary amines are preferably mono- and / or diamines. Ethylene-1,2-diamine, 1,4-diaminobutane, hexamethylene-1,6-diamine, or a mixture of two or more thereof is particularly preferred as a chemical decomposition reagent as a primary or secondary organic amine.

[0062] The chemical decomposition reaction of the polyurethane material with the chemical decomposition reagent to give the organically modified carbamate is preferably carried out at a temperature in the range of 140°C to 220°C, preferably 170°C to 200°C. This temperature should also preferably be observed when simultaneously converting the polyurethane material with hydrolysis in one step. There are no particular pressure requirements. The reaction can be carried out either at reduced or elevated pressure, for example, from 200 mbar (abs) to 2000 mbar (abs), preferably from 500 mbar (abs) to 1500 mbar (abs), more preferably from 900 mbar (abs) to 1300 mbar (abs), in particular at ambient pressure. Pressure figures in the context of the present invention are always expressed as absolute pressures, identified by the subscript "abs" following the unit of pressure (e.g., an absolute pressure of 900 mbar is written as "900 mbar"). (abs) ").

[0063] In a further embodiment, a process in which the obtained CO2 gas stream is at a temperature between 140°C and 220°C, preferably between 170°C and 200°C, is preferred.

[0064] The step of scrubbing the resulting carbon dioxide to remove secondary components, especially nitrogen, oxygen, chemical decomposition reagents (e.g., diethylene glycol), sulfur compounds, dust, and water, can be preferably carried out by at least one cleaning method selected from condensation, adsorption, catalytic gas washing, or gas scrubbing to obtain scrubbed carbon dioxide (31a). However, the CO2 gas stream obtained by the method of the present invention has excellent purity for further use in the reduction of CO2. Only a few cleaning steps may be required for the workup of CO2 prior to the reduction of CO2. These can be easily and effectively carried out. The CO2 obtained from the hydrolysis in the CO2 gas stream also contains, as major secondary components, the chemical decomposition reagents, as well as the organic amino compounds and polyols formed in the chemical decomposition. These components can be effectively removed by scrubbing (4) of the CO2 gas stream (31), in which at least the CO2 gas stream is led through a number of condensers to cool it, the organic and aqueous components present as secondary components in the gas stream condense and are separated off in liquid form, and at the end of scrubbing (4), the scrubbed CO2 gas stream (31a) is sent to reduction (6) to form carbon monoxide.

[0065] Further improvements in cleaning the CO2 gas stream are achieved when a combination of condensation and gas scrubbing is performed.

[0066] The carbon monoxide required for the synthesis of phosgene is prepared by reducing (6) CO in at least one optionally washed CO gas stream (31, 31a) produced as described above to give carbon monoxide (21a). In a further preferred embodiment of the process, the reduction of CO comprises at least A) electrochemical reduction of CO2 using electricity preferably produced from renewable energy sources; B) a reformer process in which methane (preferably biomethane) and steam are converted into carbon monoxide at a temperature of at least 500°C with the addition of at least CO2 and the supply of thermal energy; C) Conversion of hydrogen and CO2 to carbon monoxide in the reverse water gas shift RWGS reaction zone The method is carried out by a process selected from the group consisting of:

[0067] "Renewable energy" is understood by those skilled in the art to mean energy from an inexhaustible energy source, such as wind energy, hydropower, bioenergy (e.g., conversion of biogas or biomass into electricity), or solar energy. Thus, suitable renewable energy is most preferably either wind power, solar energy, hydropower, or a mixture thereof.

[0068] In carrying out the reduction of CO, the optionally washed CO gas stream for reduction (6) is preferably introduced into an electrolyzer and reduced to carbon monoxide at an electrode, preferably a gas diffusion electrode (more preferably using electricity produced from renewable energy).

[0069] CO electrolysis can be high-temperature electrolysis, for example operated at temperatures above 600°C, optionally with the addition of water for the production of synthesis gas. High-temperature electrolysis is known in principle and is available on the market, for example as eCO® from Haldor Topsoe. High-temperature electrolysis results in the formation of oxygen at the anode. A disadvantage of known high-temperature electrolysis is its low scalability, so that for larger amounts of CO, for example above 1 t / h, low-temperature electrolysis is still preferred.

[0070] When CO2 electrolysis is operated as low temperature electrolysis, the electrolysis is carried out at a temperature below 150°C.

[0071] In all CO2 electrolysis, CO2 gas is supplied to the cathode space.

[0072] In the case of low-temperature electrolysis, CO2 is converted at the gas diffusion electrode, in particular to carbon monoxide and optionally to hydrogen. At the same time, O2 or, alternatively, chlorine may also be produced at the anode. If chlorine is produced at the anode, this chlorine may be supplied to phosgene synthesis and thus to isocyanate production as a further feedstock. Those skilled in the art are aware of electrodes and methods for carrying out the electrochemical reduction of CO2, for example, from WO 2021 / 069470. More preferably, the electrochemical reduction of CO2 is carried out by the method of WO 2021 / 069470. This document is expressly and fully incorporated herein by reference. In this preferred electrolysis process for producing carbon monoxide, carbon monoxide, optionally hydrogen, and chlorine are obtained by electrochemical conversion of carbon dioxide and an alkali metal chloride solution. This preferred electrolysis process is characterized in that carbon dioxide is electrochemically reduced in an alkali metal chloride-containing aqueous solution as the catholyte at a gas diffusion electrode as the cathode, and simultaneously chlorine is produced anodically from the alkali metal chloride-containing aqueous solution as the anolyte, and then the alkali metal salt of carbonate formed in the catholyte, selected from alkali metal carbonates, alkali metal bicarbonates or mixtures thereof, reacts with hydrogen chloride to give carbon dioxide and alkali metal chloride, the released carbon dioxide is returned to the cathode space of the gas diffusion electrode, and the produced alkali metal chloride is returned to either the anode space and / or the cathode space.

[0073] According to known principles, the MEA (membrane electrode assembly) concept can also be used in low-temperature electrolysis. In this case, a catalyst is applied to the membrane. An upstream gas diffusion layer regulates the transport of gas and liquid. This can be done on both the anode and cathode sides. It is also possible to have the gas diffusion electrodes in direct contact with the membrane.

[0074] The gas diffusion electrodes used may be installed in the electrolysis cell in a zero-gap or finite-gap configuration. A preferred configuration for the low-temperature electrolysis of CO2 is described in WO 2020 / 057998, which is expressly and fully incorporated by reference.

[0075] Excess CO can be supplied to the cathode space or to the gas diffusion electrode stored therein. "Excess" means introducing more CO than would be required for stoichiometric conversion based on the current flowing. Thus, a gas mixture consisting of unreacted CO, CO, and H leaves the cathode space.

[0076] A suitable reformer process in which methane (preferably biomethane) and water vapor are converted to carbon monoxide at a temperature of at least 500°C with the addition of at least said CO2 and the supply of thermal energy is described in PCT application no. PCT / EP2022 / 052267, to which reference is expressly and fully incorporated. This process provides for the preparation of carbon monoxide from methane, water vapor and CO2 to prepare phosgene for the synthesis of organic isocyanates, comprising at least the following steps: synthesizing carbon monoxide in a reformer process in which methane and steam are converted into a carbon monoxide-containing product gas at a temperature of at least 500°C with the addition of at least CO2 and the supply of thermal energy; scrubbing the carbon monoxide-containing product gas obtained from the synthesis above by removing at least CO, and optionally additionally by removing at least one selected from water, hydrogen, or a combination thereof, to obtain carbon monoxide; providing CO2 for said addition to said reformer process from said removal of CO2 in at least said washing step. Including, however, 1) The thermal energy supplied to the reformer process for the synthesis of carbon monoxide is provided by at least one method selected from: (i) combustion of fuel containing hydrogen produced by renewable energy; (ii) combustion of fuel containing methane from biological sources; (iii) conversion of electrical energy generated from renewable energy into heat; or 2) CO2 is additionally supplied from a further CO2 source to provide CO2 added to the synthesis in the reformer process described above, or 3) A combination of the above options 1) and 2) is selected; Regarding the preparation of carbon monoxide.

[0077] A methane source useful for the reformer process is more preferably methane from biological sources. "Biological methane" (also called "biomethane") is considered by those skilled in the art to mean methane obtained industrially by methane fermentation from biomass, as opposed to fossil methane. Methane fermentation is known to mean the anaerobic decomposition of organic matter by microorganisms. Biological methane is produced, for example, in biogas plants, where both organic waste and renewable raw materials are correspondingly fermented.

[0078] The additional CO source used in step 2) above is preferably at least one external CO source that contributes to the CO not released by the method of the present invention. Examples of external CO sources include CO obtained from H production for cement production or ammonia synthesis, CO formed in off-gas during fuel combustion (e.g., waste incineration), or CO extracted from air. In a preferred embodiment of the method of the present invention, this CO from an external CO source is obtained by absorbing a CO fraction from (i) a process gas or off-gas selected from at least one process selected from cement production, H production, and incineration, and / or (ii) air by introducing it into an alkali metal hydroxide solution, e.g., potassium hydroxide solution. This results in the formation of potassium bicarbonate, which can then be thermally decomposed back to CO and potassium hydroxide. The released CO is then fed to a reformer process for the synthesis of carbon monoxide. The released CO can also be additionally fed to the reduction of CO in A) (electrochemical reduction) or C) (RWGS reaction), regardless of the implementation of the reformer process.

[0079] In a particularly preferred embodiment of the method of the present invention, carbon monoxide is prepared from said CO by at least one reaction of hydrogen with CO in a reverse water gas shift (RWGS) reaction to give carbon monoxide, in particular for the synthesis of phosgene. Such an embodiment is described, for example, in WO 2021 / 089737, which is expressly and fully incorporated herein by reference. A very particularly preferred embodiment of the method according to the present invention is characterized in that a hydrogen stream is provided and converted (in particular in a reaction zone) by the principle of the reverse water gas shift reaction together with an optionally scrubbed CO gas stream into a product gas comprising carbon monoxide and optionally by-products.

[0080] A "reaction zone" is a portion of the reaction space in which a chemical reaction, e.g., a reverse water gas shift reaction, proceeds. A "reaction chamber" is a volume in which co-reactants involved in a chemical reaction are brought together and the chemical reaction occurs. In the case of a chemical reaction, this can be, for example, the volume of a vessel in which a reactant, e.g., carbon dioxide in the case of a RWGS reaction, and its co-reactant, hydrogen in the case of a RWGS reaction, reside together and react in the reaction zone.

[0081] This particularly preferred method comprises at least the following steps for the production of carbon monoxide: supplying the hydrogen gas provided together with said CO gas stream to a RWGS reaction zone and reacting the reactants according to the principles of the RWGS reaction to provide a product gas mixture comprising water vapor, CO, and optionally by-products, particularly lower hydrocarbons, particularly preferably methane; separating unconverted carbon dioxide from the gas mixture of the RWGS reaction obtained from the separation, in particular by amine scrubbing, and recycling the unconverted carbon dioxide to the RWGS reaction; separating the hydrogen not converted in the RWGS reaction from the gas mixture of carbon monoxide and hydrogen obtained after the separation, in particular using a cold box, and recycling the hydrogen to the RWGS reaction; feeding the remaining carbon monoxide from the separation to the synthesis of phosgene; It is very particularly preferable to carry out

[0082] The RWGS reaction is preferably carried out in the presence of at least one catalyst, the latter more preferably selected from the group consisting of:

[0083] (I) Formula A (1-w-x) A' w A” x B (1-y-z) B' y B” z O 3-デルタ Mixed metal oxides During the ceremony, A, A' and A" are independently selected from the group Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Sn, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Tl, Lu, Ni, Co, Pb, Bi and / or Cd; B, B' and B" are independently selected from the group Cr, Mn, Fe, Bi, Cd, Co, Cu, Ni, Sn, Al, Ga, Sc, Ti, V, Nb, Ta, Mo, Pb, Hf, Zr, Tb, W, Gd, Yb, Mg, Li, Na, K, Ce and / or Zn; 0≦w≦0.5, 0≦x<0.5, 0≦y≦0.5, 0≦z≦0.5 and −1≦delta≦1;

[0084] (II) Formula A (1-w-x) A' w A” x B (1-y-z) B' y B” z O 3-デルタ mixed metal oxides of the formula: A, A' and A" are independently selected from the group Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Sn, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Tl, Lu, Ni, Co, Pb and / or Cd; B is selected from the group Cr, Mn, Fe, Bi, Cd, Co, Cu, Ni, Sn, Al, Ga, Sc, Ti, V, Nb, Ta, Mo, Pb, Hf, Zr, Tb, W, Gd, Yb, Mg, Cd, Zn, Re, Ru, Rh, Pd, Os, Ir and / or Pt; B' is selected from the group Re, Ru, Rh, Pd, Os, Ir and / or Pt, and B" is selected from the group Cr, Mn, Fe, Bi, Cd, Co, Cu, Ni, Sn, Al, Ga, Sc, Ti, V, Nb, Ta, Mo, Pb, Hf, Zr, Tb, W, Gd, Yb, Mg, Cd and / or Zn; 0≦w≦0.5, 0≦x≦0.5, 0≦y≦0.5, 0≦z≦0.5 and −1≦delta≦1;

[0085] (III) a mixture of at least two different metals M1 and M2 on a support comprising an oxide of Al, Ce and / or Zr doped with a metal M3; wherein M1 and M2 are independently selected from the group Re, Ru, Rh, Ir, Os, Pd and / or Pt; M3 is selected from the group Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and / or Lu;

[0086] (IV) Formula LO x (M (y / z) Al (2-y / z) O3) z mixed metal oxides of the formula: L is selected from the group Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Sc, Y, Sn, Pb, Pd, Mn, In, Tl, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and / or Lu; M is selected from the group Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Zn, Cu, Ag and / or Au; 1 <x≦2、0<y≦12および4≦z≦9であり、

[0087] (V) Formula LO(Al2O3) z mixed metal oxides of the formula: L is selected from the group Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Sc, Y, Sn, Pb, Mn, In, Tl, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and / or Lu; 4≦z≦9,

[0088] (VI) Ni and Ru-containing oxide catalysts,

[0089] (VII) a metal M1 and / or at least two different metals M1 and M2 on and / or in a support, wherein the support is carbides, oxycarbides, carbonitrides, nitrides, borides, silicides, germanides and / or selenides of metals A and / or B, M1 and M2 are independently selected from the group consisting of Cr, Mn, Fe, Co, Ni, Re, Ru, Rh, Ir, Os, Pd, Pt, Zn, Cu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and / or Lu; A and B are independently selected from the group Be, Mg, Ca, Sc, Ii, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Hf, Ta, W, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and / or Lu; and / or the reaction product of (I), (II), (III), (IV), (V), (VI) and / or (VII) in the presence of carbon dioxide, hydrogen, carbon monoxide and / or water at a temperature of 700°C or greater and at least one compound selected from the group consisting of:

[0090] In a further embodiment, the hydrogen stream provided to the RWGS reaction is preferably obtained by water electrolysis to give hydrogen and oxygen. Water electrolysis to produce hydrogen gas is the electrochemical conversion of water. Here, water is split into hydrogen and oxygen using electricity. A known method is proton exchange electrolysis (PEM electrolysis), which is described, for example, in EP 3489394 A1. A further method is alkaline water electrolysis. The two methods differ, in particular, in process parameters, such as temperature, pressure, and pH. However, both methods result in the target products of water and oxygen gas. Water electrolysis can be carried out in conventional plants. Industrial systems for alkaline water electrolysis and PEM electrolysis are known and commercially available. The principle of water electrolysis is described, for example, in Chapter 6.3.4 of Volkmar M. Schmidt's "Elektrochemische Verfahrenstechnik" [Electrochemical Methods Technology] (2003 Wiley-VCH-Verlag; ISBN 3-527-29958-0).

[0091] It is particularly preferred if the water electrolysis (5) to provide the hydrogen stream is carried out using electricity generated from renewable energy, in particular renewable energy in the form of wind, solar or hydropower.

[0092] The carbon monoxide obtained from the reduction of CO2 is optionally washed to remove any by-products present and is used in the synthesis of phosgene, which is achieved by reacting at least chlorine gas with carbon monoxide, the reacted carbon monoxide being at least the carbon monoxide from the reduction of CO2, and emitting phosgene.

[0093] The carbon monoxide is preferably washed prior to use in the synthesis of phosgene by at least the following steps: removing water; removing unconverted carbon dioxide from the gas mixture obtained from the removal of water, in particular by amine scrubbing, and recycling the unconverted carbon dioxide to the reduction of CO in the process of the invention; removing any hydrogen present from the gas mixture obtained after removal of the unconverted carbon dioxide, in particular using a cold box; This is done by:

[0094] In a further preferred embodiment of the method, carbon dioxide is separated off after water has been previously separated from the carbon monoxide-containing product gas. For this purpose, the carbon monoxide-containing gas is first fed to a water removal unit, where water is separated off, and the dry carbon monoxide-containing product gas obtained after water separation is fed to a CO2 removal unit, where CO2 is separated off. In the water removal unit, water is separated off, for example, by cooling the carbon monoxide-containing gas and separating off the water, for example as a condensate.

[0095] What is meant here in particular by "amine scrubbing" is the fundamentally known scrubbing by the principle of chemical adsorption with amines such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) or diglycolamine (DGA), which achieves a purified gas mixture of high purity even at relatively low pressures in the absorption column.

[0096] In a preferred process variant according to the present invention, carbon monoxide-containing gas (preferably from which water and CO2 have been removed) is introduced into an H2-CO2 separation unit, where hydrogen is separated and removed. This results in the formation of at least one gas stream, the gas at 25°C and 1013 mbar containing at least 95% by volume of carbon monoxide, more preferably at least 99% by volume of carbon monoxide. The introduced product gas is preferably first separated into two gas streams in the H2-CO2 separation unit. This results in a gas stream containing at least 95% by volume (preferably at least 99% by weight) of carbon monoxide, and a further gas, in particular in the form of a gas stream mainly composed of hydrogen and also containing carbon monoxide and methane. The further gas is also called tail gas from the H2-CO2 separation, or end gas if there is no tail gas treatment. An H2-CO2 separation unit operating according to this separation principle is called a cold box. The hydrogen-containing tail gas from the H2-CO2 separation can be subjected to subsequent tail gas treatment to enrich the hydrogen. The tail gas treatment process results in a hydrogen-enriched gas in the form of a gas stream and another gas, called tail gas or end gas from the tail gas treatment, in the form of a gas stream containing a mixture of CO, methane and a smaller amount of hydrogen than the hydrogen-enriched gas.

[0097] To provide chlorine for the synthesis of phosgene useful in this embodiment, those skilled in the art are familiar with the production of chlorine gas from the electrochemical oxidation of hydrochloric acid by electrolysis using gas diffusion electrodes (HCl, also known as ODC electrolysis (ODC = oxygen depleted electrode) process; for suitable electrolysis cells, see U.S. Pat. No. 6,022,634, WO 03 / 31690, the production of chlorine gas from hydrochloric acid diaphragm electrolysis (see EP 1 103 636), the production of chlorine gas from thermal catalytic gas phase oxidation (see WO 2012 / 025483), and the production of chlorine from chloralkali electrolysis (see WO 2009 / 007366). The above cited texts relating to the production of chlorine gas are also well known. The contents of the patent application are expressly and fully incorporated by reference. In a preferred variant of this embodiment of the process, the chlorine required for the synthesis of phosgene is produced electrolytically, in particular by electrochemical oxidation by hydrochloric acid electrolysis using gas diffusion electrodes, by electrochemical oxidation by hydrochloric acid diaphragm electrolysis or by electrochemical oxidation by chloralkali electrolysis. In this case, it is particularly preferred that the electrochemical oxidation is carried out in each case using electricity generated from renewable energy, in particular renewable energy in the form of wind, solar or hydropower.

[0098] In a particularly preferred embodiment of the method, the phosgene formed by the phosgene synthesis is used in a further step for the preparation of an organic isocyanate, in which the phosgene from the phosgene synthesis reacts with at least one organic amino compound, in particular an organic amino compound obtained by hydrolysis of an organically modified carbamate, and at least an organic isocyanate is discharged. Preferably, at least an organic isocyanate and hydrogen chloride are discharged.

[0099] Generally, in this embodiment, the process of the invention is preferred in which the resulting organic isocyanate contains at least two isocyanate groups. To this end, the reactants used in the synthesis are also preferably organic amino compounds having at least two amino groups, in particular organic amino compounds obtained by hydrolysis of organically modified carbamates.

[0100] More preferably, the organic isocyanates obtained contain at least two isocyanate groups and have a molar mass of less than or equal to 1000 g / mol, in particular less than or equal to 800 g / mol.

[0101] Very particularly preferably used organic amines are selected from tolylenediamine (TDA), methylenedi(phenylamine) (MDA) (preferably selected in turn from diphenylmethane-2,2'-diamine, diphenylmethane-2,4'-diamine, diphenylmethane-4,4'-diamine or mixtures thereof), hexamethylenediamine, isophoronediamine, 1,3-bis(aminomethyl)benzene, cyclohexyldiamine or mixtures thereof, with TDA, MDA or mixtures thereof, in particular TDA or MDA obtained by hydrolysis of organically modified carbamates, being very particularly preferred organic isocyanates.

[0102] Very particularly preferred organic isocyanates obtained are selected from tolylene diisocyanate (TDI), methylene di(phenylisocyanate) (MDI) (preferably selected in turn from diphenylmethane 2,2'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 4,4'-diisocyanate or mixtures thereof), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)benzene (XDI), cyclohexyl diisocyanate (CHDI) or mixtures thereof, TDI, MDI or mixtures thereof being very particularly preferred organic isocyanates.

[0103] Furthermore, in embodiments involving the synthesis of organic isocyanates, it is preferred that hydrogen chloride is also formed together with the organic isocyanate. Again, it is preferred that this hydrogen chloride is provided as a reactant in the preparation of chlorine for the synthesis of phosgene. The necessary removal and purification of the hydrogen chloride formed in the production of isocyanates can then be achieved by oxidation in a thermal catalytic gas-phase oxidation reaction with oxygen to chlorine and water, and optionally using O from water electrolysis.

[0104] A further alternative approach using hydrogen chloride as a reactant for the production of chlorine is the reaction of hydrogen chloride with water to form hydrochloric acid, followed by electrochemical oxidation of the hydrochloric acid to chlorine and, optionally, hydrogen. This aqueous hydrochloric acid solution is then supplied to the aforementioned electrochemical oxidation by hydrochloric acid electrolysis using gas diffusion electrodes, electrochemical oxidation by hydrochloric acid diaphragm electrolysis, or electrochemical oxidation by chloralkali electrolysis. The O2 required for hydrochloric acid electrolysis using gas diffusion electrodes can be obtained from water electrolysis.

[0105] Hydrogen chloride resulting from isocyanate production can also be converted into hydrochloric acid after purification and absorption in water, and the resulting hydrochloric acid is sold on the market for various uses.

[0106] In a particularly preferred embodiment of the method, phosgene synthesis by reaction of at least chlorine gas with carbon monoxide previously obtained after scrubbing of the carbon monoxide-containing product gas from step c), preparing an isocyanate by reacting the resulting phosgene with at least one organic amine to form at least one organic isocyanate compound and hydrogen chloride; 1. Separation and purification of hydrogen chloride formed in the production of isocyanates and subsequent oxidation reaction of hydrogen chloride, Reaction of hydrogen chloride in a thermal catalytic gas phase oxidation with oxygen to chlorine and water, which may use oxygen from water electrolysis; Reaction of hydrogen chloride with water to form hydrochloric acid, followed by electrochemical oxidation of the hydrochloric acid to chlorine and optionally hydrogen. Separation and purification of hydrogen chloride and oxidation reaction selected from the group consisting of: Following the oxidative conversion of hydrogen chloride, feeding the chlorine formed to the synthesis of phosgene, optionally while feeding the synthesis of phosgene with an additional amount of chlorine derived from chloralkali electrolysis. will be further implemented.

[0107] The resulting organic isocyanate may be reacted in an additional step of the process with at least one organic compound having at least two hydroxy groups, in particular at least one polyester polyol or polyether polyol, to form a polyurethane material.

[0108] Correspondingly produced polyurethane materials are, for example, in the form of foams, coatings, insulating compounds and components of commercial products, which can be provided again at the end of their useful life as polyurethane materials for the method of the invention.

[0109] The present invention further provides the use of CO, which is a direct product of a process comprising at least a step of hydrolysis of at least one organically modified carbamate, in a reduction reaction (i.e., reduction of CO) to produce carbon monoxide for phosgene production.

[0110] The corresponding embodiments of the method of the invention are also applicable mutatis mutandis to this subject matter of the invention.

[0111] The present invention further provides the use of carbon monoxide, which is a direct product of a process comprising at least the reduction reaction of CO prepared by hydrolysis of at least one organic compound selected from organically modified carbamates, for the production of phosgene.

[0112] The corresponding embodiments of the method of the invention are also applicable mutatis mutandis to this subject matter of the invention.

[0113] The present invention further provides an apparatus for the production of phosgene, comprising: At least one unit for providing a CO gas stream which is a direct product of a process comprising at least a step of hydrolysis of at least one organic compound selected from organically modified carbamates, said at least one unit comprising at least one CO outlet for said CO gas stream; at least one unit for scrubbing the CO2 gas stream to remove secondary components, optionally comprising at least one unit from the group formed by a condensation unit, an adsorption unit, a gas scrubbing unit or a catalytic gas scrubbing unit, wherein the unit for scrubbing the CO2 gas stream has at least one inlet for the CO2 gas stream as the CO2 gas stream to be scrubbed, fluidly connected to a CO2 outlet of the unit for providing a CO2 gas stream, and the unit for scrubbing the CO2 gas stream has at least one outlet for the scrubbed CO2 gas stream; at least one unit for reducing the provided at least one optionally scrubbed CO gas stream to carbon monoxide, the at least one unit comprising at least one inlet for the CO gas stream, optionally via at least one unit for scrubbing the CO gas stream, fluidly connected to at least one outlet of the unit for providing the CO gas stream, and comprising at least one outlet for carbon monoxide; at least one unit for the production of phosgene, at least one inlet for chlorine gas fluidly connected to a source of chlorine gas; at least one inlet for carbon monoxide fluidly connected to at least one outlet for carbon monoxide in the unit for reduction of the CO gas stream; At least one outlet for phosgene; At least one unit comprising: An apparatus is provided, comprising:

[0114] A fluid connection is understood to mean an apparatus that connects equipment components to one another and allows a substance, which may be in any state of matter, to be transported as a material flow from one equipment component to the next equipment component, for example to an inlet in the form of a pipe. The expression "fluidly connected" means that the specified equipment components are connected to one another via a fluid connection.

[0115] A "reaction space" is the volume of an apparatus in which the co-reactants involved in a chemical reaction are present together and in which the chemical reaction takes place. In the case of a chemical reaction, this may be, for example, the volume of a vessel or container in which the co-reactants are present together and react.

[0116] A preferred embodiment of the device is suitable for carrying out simultaneous chemical decomposition transformations and hydrolysis in one step, wherein the unit for providing a CO gas stream is a unit for the hydrolysis of at least one organic compound, At least one hydrolysis device comprising at least one inlet for a chemical decomposition reagent, at least one inlet for a water-containing liquid, at least one inlet for a polyurethane material, and at least one outlet for a CO2 gas stream, wherein said organic matter and said liquid can be contacted in a reaction zone of the hydrolysis device, and the formed CO2 gas stream can be directed via said outlet. The present invention is characterized by comprising a unit comprising:

[0117] A further preferred embodiment of the device is suitable for carrying out separate chemical decomposition transformations and hydrolysis, wherein the unit for providing a CO gas stream is a unit for the hydrolysis of at least one organic compound, at least one chemical decomposition device comprising at least one inlet for a chemical decomposition reagent-containing liquid, at least one inlet for a polyurethane material, and at least one outlet for an organically modified carbamate, wherein said organic matter and said liquid can be contacted in a reaction zone of a reactor and converted to at least one organic compound selected from organically modified carbamates; at least one hydrolysis apparatus comprising at least one inlet for a water-containing liquid, at least one inlet for an organically modified carbamate, and at least one outlet for a CO2 gas stream, wherein the organically modified carbamate and the water-containing liquid can be contacted in a reaction zone of the hydrolysis apparatus, and the formed CO2 gas stream can be directed via the outlet, the inlet for the organically modified carbamate being fluidly connected to the outlet for the organically modified carbamate in a chemical decomposition reactor; The present invention is characterized by comprising a unit comprising:

[0118] In the context of this embodiment, it is further preferred that the unit for hydrolysis of at least one organic compound further comprises at least one separation device, wherein the outlet for the organically modified carbamate from the chemical decomposition device is fluidly connected to the inlet of the separation device, the separation device has at least one inlet for an organic solvent that is incompletely miscible with the previously used chemical decomposition reagent, and the separation device includes at least one outlet for the carbamate phase that is fluidly connected to a source of the organic solvent and to the inlet of the hydrolysis device. The separation device is configured so that the composition obtained by chemical decomposition, which at least contains at least one organically modified carbamate, can be contacted with the organic solvent that is incompletely miscible with the previously used chemical decomposition reagent, and after mixing and contact, phase separation into a carbamate phase (containing the organically modified carbamate) and a solvent phase can occur, from which the carbamate phase can be separated and discharged from the separation device. In this embodiment, the carbamate phase is introduced into the hydrolysis device.

[0119] In a further preferred embodiment of the device, the unit for the reduction of at least one optionally washed CO gas stream (31, 31a) provided is an electrolysis unit equipped with gas diffusion electrodes or a reverse water gas shift reactor for CO reduction. [Brief explanation of the drawings]

[0120] [Figure 1]1 is a schematic diagram of an overall process for producing low-emission toluene diisocyanate (TDI). [Figure 2] 1 is a schematic diagram of an overall process for reducing low-emission toluene diisocyanate (TDI). DETAILED DESCRIPTION OF THE INVENTION

[0121] The present invention is explained in more detail below by means of Examples 1 to 4 with reference to Figures 1 and 2, without limiting the invention to these examples. In Figures 1 and 2, the following reference numerals have in each case the definition to the right:

[0122] 1 Chemical decomposition, in this case, glycol decomposition 1a CO2 gas stream from chemical cracking (glycol cracking) 1b Addition of a chemical degradation reagent (here, diethylene glycol (DEG)) to replenish losses 1c Polyols from chemical decomposition 1d CO2 gas stream from chemical decomposition coupled with hydrolysis (here, hydroglycollysis) 1e H2O + catalyst Na2CO3 for coupled chemical decomposition and hydrolysis (here, hydroglycolysis) 2. Hydrolysis 2a CO2 gas stream from hydrolysis 2b TDA from hydrolysis 2c H2O for hydrolysis 3 Chemical degradation coupled with hydrolysis (here, hydroglycollysis) 3a Polyol solvents from hydroglycolysis 4. Solvent Extraction 4a Organically modified carbamates from organic amino compounds (here, TDA) / solvent extraction 4b Replacement of lost energy with H2O 4c Polyol toluene from solvent extraction 4d Polyols and Solvents from Solvent Extraction 5. Solvent evaporation 5a Toluene from solvent evaporation 5b Cyclohexane solvent from 5 5c Solvent replacement of losses 5d Polyol 6. Polyol production 6a Polyols from polyol manufacture 6b Discharge of residue 7. Amine Wash 7a Organic amino compounds from amine washes (here, TDA) 7b Chemical decomposition reagent from amine wash (here, DEG) 7c residue 7d H2O from amine wash 7f H2O from amine purification 8 Isocyanate Production 8a TDI 8b HCl from isocyanate production 9. Phosgene Production 9a Phosgene 10 HCl Recycle 10a Chlorine from HCl recycle 11 PU foam manufacturing 15 CO process gas treatment by cooling, drying, CO2 removal (amine scrubbing) and H2-CO separation 15a H2 from H2-CO separation 15b CO from H2-CO separation 15c CO2 from CO2 removal 20 H2 manufacturing 20a H2 from water electrolysis 20c H2O to replace water electrolysis losses 30 CO production by CO2 reduction (CO2 electrolysis or RWGS) 30a CO product gas stream from the reduction of CO 40 CO2 compression 40a Compressed CO2 41 CO2 Processing (CO2 from Chemical Decomposition) 41a CO2 from chemical decomposition after treatment 41b CO2 purge stream from 41 41c CO2 purge stream from 44 44 CO2 treatment from hydrolysis 44a Purified CO2 from hydrolysis 45 CO2 Hydroglycolysis Workup 45a Purified CO2 from hydroglycolysis workup 45b CO2 Purge from Workup 45 46 CO2 reservoir (optional) 52 Polyurethane material production (here, PU foam production) Polyurethane materials for the 52a market 54 Market / Recycling / Separation 54a Recycled PU Foam 60 Provision of polyurethane materials (here, PU foam preparation and passivation) 60a Polyurethane materials (here, PU foams based on TDI) 70 RWGS Heating - Electric or Biogas or H2

[0123] [Example]

[0124] [Example 1 (Figure 1)] Schematic diagram of the overall process for producing low-emission toluene diisocyanate (TDI), CO production by RWGS heated with bionatural gas, HCl recycling with Cl production by thermal catalytic gas-phase oxidation (Deacon) of HCl and H provided from water electrolysis, and CO provision from the chemical degradation of polyurethane materials (TDI-based foams) in separate steps with diethylene glycol (PEG) as a chemical degradation agent and hydrolysis of the resulting organically modified carbamates.

[0125] 300 kg of polyurethane material 60a in the form of a residual moisture-containing polyurethane foam having a weight proportion of 33% TDI and 67% polyol (ARCOL® Polyol 1108) is provided. This is dissolved in 300 kg of diethylene glycol as a chemical decomposition reagent with the addition of 5.5 kg of Na2CO3 as a catalyst in a chemical decomposition step 1 under an inert carbon dioxide atmosphere. Before hydrolysis step 2, the product mixture obtained by dissolution with 227.1 kg of polyol, 251.1 kg of diethylene glycol, and 119.6 g of TDA / organically modified carbamate is introduced into solvent extraction step 4 using toluene as the solvent, which is carried out similarly to the examples in WO 2020 / 260387. The solvent phase obtained after phase separation, containing 1,367 kg of toluene and 227.1 kg of polyol, is transferred to solvent evaporation step 5, where the toluene solvent is substantially completely separated from the polyol and recycled to solvent extraction step 4. The resulting polyol is subjected to further workup in Polyol Preparation 6.

[0126] The carbamate phase obtained after phase separation in solvent extraction 4, containing 119.6 kg of TDA / organically modified carbamate, is transferred to hydrolysis 2, where it is hydrolyzed in an inert carbon dioxide atmosphere at 180°C for 2.5 hours with the addition of a total of 16.5 kg of water. Overall, a liquid composition containing 51.1 kg of TDA and 300 kg of diethylene glycol, as well as CO gas stream 2a, is obtained. The liquid composition is transferred to amine wash operation 7, where it is separated into 47.92 kg of TDA 7a, approximately 300 kg of diethylene glycol 7b, and residual material 7c.

[0127] Gas stream 1a with 3.7 kg / h of CO2 containing traces of N2 and O2, DEG, water is withdrawn from chemical decomposition 1 and sent to CO2 workup 41. Gas stream 1a is heated to a temperature of 180°C and 1.01 bar. (abs) The gas stream 1a is cooled to 25°C by a heat exchanger, removing most of the water and DEG.

[0128] Gas stream 1a is then dried by zeolite, side stream 41a is purged with 0.3 kg of CO2 and tail gas stream 41a having 3.4 kg of CO2 is sent to compression operation 40 at 25°C.

[0129] From hydrolysis 2 is drawn off a CO gas stream 2a containing 33.2 kg / h of CO and traces of N and O, DEG, water, and toluene. This gas stream is heated to a temperature of 180° C. and a pressure of 1.01 bar. (abs) Gas stream 2a is cooled to 25°C by a heat exchanger, removing most of the water and DEG.

[0130] The cooled gas stream is then dried over zeolite, a side stream is purged with 2 kg / h of CO2 and a tail gas stream 44a having 31.2 kg / h of CO2 is sent to the compression operation 40 at 25°C.

[0131] A continuous gas stream 40a having 34.6 kg / h of CO2 at 30 bar and 40°C is withdrawn from the compressor stage 40 and sent to a CO production operation in the form of a RWGS by reduction 30 of CO2 in the reaction space of the RWGS.

[0132] The RWGS reaction is carried out at 802°C, while the reaction temperature is maintained by the introduction and combustion of bionatural gas. It may also be possible to use H2 for heating or to use electrical heating. 34.6 kg / h of CO2 from water electrolysis 20 and 1.57 kg / h of H220a are introduced into the RWGS reaction space for CO production by reduction of CO2 30, which is carried out at a temperature of 802°C and 30 bar.

[0133] The resulting product gas mixture 30a, consisting of CO, HO, unconverted CO and unconverted H, and by-products, primarily small amounts of methane, is withdrawn from the RWGS reaction and cooled in the process gas cooling operation of CO process gas treatment operation 15.

[0134] The gas mixture is then sent to a process gas drying operation in the CO process gas treatment operation 15 to remove a total of approximately 14.1 kg / h of water. This water is sent to water electrolysis 20.

[0135] A total of 1.57 kg / h of hydrogen is removed from the water electrolysis 20 and 14.13 kg / h of water is supplied to the water electrolysis, which consists of recycled water from the process gas drying operation and freshly added water.

[0136] The remaining gas mixture from the process gas drying operation is sent to a CO2 removal operation in a CO process gas treatment operation 15. The CO2 is removed by amine scrubbing and the removed CO2 15c is returned to the reduction of CO2 30 (RWGS reaction).

[0137] Energy for CO removal from the formed CO2-amine complex comes from the process gas cooling operation described above, where the RWGS reaction gas is cooled. The CO2-depleted gas is sent to H2-CO separation in the CO process gas treatment operation 15. A cold box is used for H2-CO separation, where the H2-CO gas mixture is cooled and hydrogen and CO are separated. The removed hydrogen (15a) is returned to the RWGS reaction (31). 22.0 kg / h of CO2 15b from the H2-CO separation is sent to the phosgene synthesis 9. In the latter, CO2 15b is reacted with 55.78 kg / h of chlorine 10a removed from the HCl recycle process 10. HCl gas is converted to chlorine by thermal catalytic gas-phase oxidation (Deacon) of HCl from the isocyanate production 8. O2 from the water electrolysis 20 may be used to oxidize HCl gas in the Deacon process 10.

[0138] 77.78 kg / h of phosgene are withdrawn from the phosgene synthesis 9 and reacted in the isocyanate production 8 with 47.92 kg / h of toluenediamine 7a to give 68.35 kg / h of toluenediisocyanate 8a.

[0139] The resulting HCl gas in an amount of 57.35 kg / h is sent, after cleaning by low-temperature distillation, to the production of Cl2 by thermal catalytic gas-phase oxidation 10, where it reacts with oxygen to give chlorine and HO over a catalyst based on ruthenium oxide at about 300 °C. The required oxygen (12.57 kg / h) is extracted from the water electrolysis 20.

[0140] The resulting toluene diisocyanate (68.35 kg / h) 8a is reacted again with 227.1 kg / h of polyol (essentially corresponding to the specifications of ARCOL® Polyol 1108) 6a obtained from this process to give 295.44 kg / h of polyurethane material in PU foam production 52.

[0141] After the polyurethane material has been used in various applications in the market 54, it can be collected and recycled to provide the polyurethane material obtained therefrom as a valuable material for chemical decomposition (1) after treatment and processing 60.

[0142] Hydrogen 20a is produced in the water electrolysis 20 using renewable energy with 0.088 MW of power. The water electrolysis 20 operates at a power output of 8 kA / m per electrolysis element. 2 and a cell voltage of 2 V. Here, 0.088 MW and 14.13 kg / h of water (16a+20c) are supplied, in each case from the removal of CO from the process gas treatment operation 15, from the process gas cooling operation and the process gas drying operation, and from the outside. 1.57 kg / h of H2 and 12.56 kg / h of oxygen are withdrawn from the water electrolysis.

[0143] The method of the present invention allows for substantially complete recycling of all raw materials of TDI-based PU materials, such as amines and polyols, thus completing the value creation cycle.

[0144] The use of renewable energy in water electrolysis further reduces the CO2 footprint of phosgene produced from CO and Cl2, thus enabling greater sustainability of the production of TDI or the resulting PU material.

[0145] [Example 2 (Figure 1)] This example corresponds to Example 1, except for the implementation of CO2 reduction.

[0146] As a CO reduction 30, low temperature CO electrolysis is carried out. The CO electrolysis is suitably operated in accordance with European Patent Application No. 18195279.7, Example 1. The electrolysis is carried out at 1.2 bar. (abs) Electrode area 1.6m 2 Each cell uses 10 elements, which are connected together to form an electrolytic cell. The electrolysis is carried out at a cell voltage of 3.7 V and a current of 4.05 kA / m 2 It operates at a current density of 0.239 MWh, with a current yield of 65% relative to CO. It consumes 0.239 MWh of renewable energy, primarily wind, corresponding to a terminal power of 0.239 MW.

[0147] 34.6 kg / h of CO2 is delivered to the sump after drying, washing and compression at 41 and at 1.2 bar. (abs) The gas mixture 30a is extracted from the CO2 electrolysis 30 with 22 kg / h of CO, 200 kg / h of CO2, and 0.85 kg / h of H2.

[0148] Additionally, 19.36 kg / h of O2 is extracted from the anode space.

[0149] The gas mixture 30a produced from electrolysis 30 is sent to a process gas treatment operation 15 having a drying operation in the form of an amine scrub and a CO2 removal operation, where unconverted CO2 15c is separated from the mixture and returned to electrolysis 30. The CO2-depleted gas, consisting of CO and H2, is fed to a CO-H2 separation in the form of a cold box where CO and H2 are separated. 22 kg / h of CO2 15b are reacted with Cl2 10a coming from the HCl recycle 10 to give phosgene 9a in phosgene production 9, which is reacted with TDA 7a coming from hydrolysis 2 and amine wash 7 to give TDI 8a in isocyanate production 8.

[0150] [Example 3 (Figure 2)] Figure 2 is a schematic diagram of the overall process for the reduction of low-emission toluene diisocyanate (TDI), including the rWGS reaction, chlorine production, PU production, use, and utilization of polyurethane material waste and recycling by hydroglycolysis and use of CO2 for the RWGS reaction. 300 kg of polyurethane material 60a in the form of a residual moisture-containing polyurethane foam having a weight percentage of 33% TDI and 67% polyol (ARCOL® Polyol 1108) is provided. This is reacted with 300 kg of diethylene glycol as a chemical decomposition agent in a combined chemical decomposition and hydrolysis (here, hydroglycolysis) 3 under an inert carbon dioxide atmosphere together with a total of 16.5 kg of water, with the addition of 5.5 kg of Na2CO3 as catalyst, in a manner similar to that described in Example x of WO XXX. A product solution 3a and a CO2 gas stream 1d are obtained.

[0151] After the reaction, the product solution is transferred to solvent extraction 4 and mixed with 1866 kg of cyclohexane. The solvent phase 4d obtained after phase separation, comprising 1866 kg of cyclohexane, 223.6 kg of polyol, and 1.8 kg of residual material, is transferred to solvent evaporation 5, where the cyclohexane solvent is substantially completely separated from the polyol and recycled to solvent extraction 4. The resulting polyol was subjected to further workup in polyol production 6 and separated from residual material 6b.

[0152] The amine-containing phase (TDA) obtained in solvent extraction 4 after phase separation, containing 52 kg of TDA water, salts and 300 kg of DEG, is transferred to an amine wash operation 7 where it is separated into 47.92 kg of TDA 7a and approximately 300 kg of diethylene glycol 7b and residual material 7c.

[0153] Gas stream 1d with 37.4 kg / h of CO2 containing traces of N2 and O2, DEG, water is withdrawn from the hydroglycolysis 3 and fed to the CO2 workup 45. Gas stream 1d is at a temperature of 180°C and 1.01 bar. (abs) Gas stream 1d is cooled to 25°C by a heat exchanger, removing most of the water and DEG.

[0154] Gas stream 1d is then dried by zeolite, side stream 45b is purged with 2.8 kg of CO2 and tail gas stream 45a with 34.6 kg / h of CO2 is sent to compression operation 40 at 25°C.

[0155] A continuous gas stream 40a having 34.6 kg / h of CO2 at 30 bar and 40°C is withdrawn from the compressor stage 40 and sent to a CO production operation in the form of a RWGS by reduction 30 of CO2 in the reaction space of the RWGS.

[0156] The RWGS reaction 30 is carried out at 802°C, with the reaction temperature maintained by the introduction and combustion of bionatural gas. It may also be possible to use H2 for heating or electrical heating. 34.6 kg / h of CO240a and 1.57 kg / h of H220a from the water electrolysis 20 are introduced into the RWGS reaction space 30, which is carried out at a temperature of 802°C and 30 bar.

[0157] The resulting product gas mixture 30a, consisting of CO, H2O, unconverted CO2 and unconverted H2, and by-products, primarily small amounts of methane, is withdrawn from the RWGS reaction and cooled in the process gas cooling operation of process gas treatment operation 15.

[0158] The gas mixture is then sent to a process gas drying operation in a process gas treatment operation 15 to remove a total of approximately 14.1 kg / h of water. This water is sent to water electrolysis 20.

[0159] A total of 1.57 kg / h of hydrogen 20a is removed from the water electrolysis 20 and 14.13 kg / h of water is supplied to the water electrolysis, which consists of recycled water from the process gas drying operation described above and freshly added water.

[0160] The remaining gas mixture from the process gas drying operation is fed to a CO2 removal operation in the process gas treatment operation 15. The CO2 is removed by amine scrubbing and the removed CO2 15c is returned to the RWGS reaction 30.

[0161] Energy for CO2 removal from the formed CO2-amine complex comes from the process gas cooling operation in the process gas treatment operation 15, where the RWGS reaction gas 30a is cooled. The CO2-depleted gas is sent to H2-CO separation in the process gas treatment operation 15. A cold box is used for H2-CO separation, where the H2-CO gas mixture is cooled and hydrogen and CO are separated. The removed hydrogen 15a is returned to the RWGS reaction 30. 22.0 kg / h of CO2 15b from the H2-CO separation is sent to the phosgene synthesis 9. In the latter, CO2 15b reacts with 55.78 kg / h of chlorine 10a removed from the HCl recycle process 10. HCl gas is converted to chlorine by thermal catalytic gas-phase oxidation (Deacon) of HCl from the isocyanate production 8. O2 from the water electrolysis 20 may be used for the oxidation of HCl gas in the Deacon process 10.

[0162] 77.78 kg / h of phosgene are withdrawn from the phosgene synthesis 9 and reacted in the isocyanate production 8 with 47.92 kg / h of toluenediamine 7a to give 68.35 kg / h of toluenediisocyanate 8a.

[0163] The resulting HCl gas in an amount of 57.35 kg / h is sent, after cleaning by low-temperature distillation, to the production of Cl by thermal catalytic gas-phase oxidation (10), where it reacts with oxygen to give chlorine and HO over a catalyst based on ruthenium oxide at about 300 °C. The required oxygen (12.57 kg / h) is extracted from the water electrolysis 20.

[0164] The resulting toluene diisocyanate (68.35 kg / h) 8a is reacted again with 223.6 kg / h of polyol (essentially corresponding to the specifications of ARCOL® Polyol 1108) 6a obtained from this process to give 291.95 kg / h of polyurethane material in PU foam production 52.

[0165] After the polyurethane material has been used in various applications in the market 54, it can be collected and recycled to provide the polyurethane material waste obtained therefrom for hydroglycolysis 3 after treatment and processing 60.

[0166] Hydrogen 20a is produced in the water electrolysis 20 using renewable energy with 0.088 MW of power. The water electrolysis 20 operates at a power output of 8 kA / m per electrolysis element. 2 and a cell voltage of 2 V. Here, 0.088 MW and 14.13 kg / h of water are supplied to the process gas cooling operation of the process gas treatment (PGP) operation 15, the process gas drying operation of the PGP 15, and externally. 1.57 kg / h of H2 and 12.56 kg / h of oxygen are extracted from the water electrolysis.

[0167] The method of the present invention allows for substantially complete recycling of all raw materials of TDI-based PU materials, such as amines and polyols, thus completing the value creation cycle.

[0168] The use of renewable energy in water electrolysis further reduces the CO2 footprint of phosgene produced from CO and Cl2, thus enabling sustainably produced TDI or resulting PU materials.

[0169] [Example 4 (Figure 2)] This example corresponds to Example 3, except for the implementation of CO2 reduction.

[0170] For CO2 reduction 30, low-temperature CO2 electrolysis as described in Example 2 is carried out.

Claims

1. 1. A method for producing phosgene, comprising at least the following steps: CO ２ Producing a gas stream (31) comprising at least the following steps: providing at least one organically modified carbamate; The at least one organically modified carbamate is hydrolyzed to produce at least an organic amino compound and CO ２ forming a The CO formed ２ At least one CO ２ Obtaining a gas flow By CO ２ producing a gas flow; Preferably, the CO is removed by at least one cleaning method selected from condensation, adsorption, catalytic gas washing or gas scrubbing. ２ scrubbing (4) the gas stream (31) to remove secondary components, in particular secondary components selected from at least one compound from the list formed by alcohols, polyethers, hydrocarbons, organic amines, water, sulfur compounds, dust, oxygen and nitrogen, to obtain scrubbed carbon dioxide (31a); At least one optionally washed CO ２ CO in the gas stream (31, 31a) ２ to carbon monoxide (21a); a step (1) of synthesizing phosgene (20) from at least the carbon monoxide (21a) and chlorine (22) obtained by the reduction; A method for producing phosgene by

2. The provided organically modified carbamates are prepared by at least the following method steps: providing a polyurethane material; reacting the provided polyurethane material with at least one chemical decomposition reagent selected from (a) a primary or secondary organic amine, (b) an amino alcohol having a primary or secondary amino group, or (c) an alcohol having at least one hydroxyl group to form at least one organically modified carbamate; 10. The method of claim 1, wherein the polyurethane material is at least one direct process product of chemical decomposition, including:

3. The CO ２ The gas stream (31) is subjected to at least the following steps: providing a polyurethane material; reacting the provided polyurethane material with at least one chemical decomposition reagent selected from (a) a primary or secondary organic amine, (b) an amino alcohol having a primary or secondary amino group, or (c) an alcohol having at least one hydroxyl group to form at least one organically modified carbamate; The preformed organically modified carbamate is hydrolyzed to form at least an organic amino compound and CO ２ forming a The CO formed ２ At least one CO ２ obtaining a gas flow; 3. The method according to claim 1 or 2, characterized in that the polyurethane is produced by chemical decomposition of a polyurethane material comprising:

4. 4. The method of claim 3, wherein the reaction of the provided polyurethane material to give the organically modified carbamate and the hydrolysis of the carbamate are carried out together in one method step.

5. The obtained CO ２ A process according to any one of claims 2 to 4, characterized in that the gas stream is at a temperature of between 140°C and 220°C, preferably between 170°C and 200°C.

6. 6. A method according to any one of claims 2 to 5, characterized in that the reaction of the provided polyurethane material to give the organically modified carbamate is carried out using at least one catalyst chosen in particular from carbonates, hydrogen carbonates, orthophosphates, monohydrogen orthophosphates, metaphosphates, hydroxides, organic amines, organometallic compounds or a mixture of two or more of the aforementioned catalysts.

7. 7. The method according to any one of claims 2 to 6, characterized in that the chemical degradation reagent is selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methyl glycol, triethylene glycol, glycerol, 2-methylpropane-1,3-diol or a mixture of two or more of the aforementioned alcohols.

8. The CO ２ The gas stream (31) is scrubbed (4) to remove secondary components, in this case at least the CO ２ The gas stream is cooled by being led through a number of condensers, in which organic and aqueous components present as secondary components in said gas stream are condensed and separated off in liquid form, and at the end of said scrubbing (4), scrubbed CO ２ A method according to any one of the preceding claims, characterized in that a gas stream (31a) is sent to said reduction (6) to form carbon monoxide.

9. A hydrogen stream (29a) is provided and, by the principle of the reverse water gas shift reaction, the optionally scrubbed CO ２ 9. The method according to claim 1, wherein the gas stream (31, 31a) is converted together with the carbon monoxide (21) with or without by-products (32) into a product gas (39) containing carbon monoxide (21).

10. 10. The method of claim 9, characterized in that the hydrogen stream (29a) is provided by carrying out electrolysis (5) of water (26) to give hydrogen (29) and oxygen (27).

11. 11. The method according to claim 10, characterized in that the water electrolysis (5) is carried out using electricity generated from renewable energy, in particular renewable energy in the form of wind, solar or hydropower.

12. The optionally washed CO ２ 12. The method according to any one of claims 1 to 11, characterized in that the gas stream is introduced into an electrolysis device for said reduction (6) and reduced to carbon monoxide at an electrode, preferably a gas diffusion electrode.

13. 1. An apparatus for the production of phosgene, comprising: CO is the direct product of a process comprising at least a step of hydrolysis of at least one organic compound selected from organically modified carbamates. ２ At least one unit for providing a gas flow, said CO ２ At least one CO for the gas stream ２ at least one unit having an outlet; Optionally, said CO 2 treatment system comprises at least one unit from the group formed by a condensation unit, an adsorption unit, a gas scrubbing unit or a catalytic gas washing unit. ２ At least one unit for scrubbing the gas stream (31) to remove secondary components, said CO ２ The unit for scrubbing a gas stream comprises: ２ The CO of the unit for providing a gas flow ２ a CO2 to be cleaned, fluidly connected to the outlet; ２ The CO as a gas stream ２ at least one inlet for a gas stream (31), ２ The unit for scrubbing a gas stream comprises scrubbed CO ２ at least one unit having at least one outlet for a gas flow; At least one optionally scrubbed CO provided to carbon monoxide (21a) ２ At least one unit for reducing a gas stream (31, 31a), comprising: ２ a CO 2 gas supply fluidly connected to at least one outlet of said unit for providing a gas flow; ２ CO may be passed through at least one of said units for scrubbing the gas stream. ２ at least one unit comprising at least one inlet for a gas stream and at least one outlet for carbon monoxide; At least one unit for the production of phosgene, at least one inlet for chlorine gas fluidly connected to a source of chlorine gas; The CO ２ at least one inlet for carbon monoxide fluidly connected to at least one outlet for carbon monoxide in said unit for reduction of a gas stream; at least one outlet for phosgene; At least one unit comprising: An apparatus comprising:

14. CO ２ said unit for providing a gas stream is a unit for the hydrolysis of at least one organic compound, at least one inlet for a liquid containing water and chemical decomposition reagents, at least one inlet for a polyurethane material, and ２ and at least one hydrolysis unit having at least one outlet for a gas stream, wherein the polyurethane material and the liquid can be contacted in a reaction zone of the hydrolysis unit, and the CO formed ２ at least one hydrolysis unit capable of directing a gas stream through said outlet; 14. Apparatus according to claim 13, characterized in that it comprises a unit for hydrolysis comprising:

15. CO ２ said unit for providing a gas stream is a unit for the hydrolysis of at least one organic compound, at least one chemical decomposition device comprising at least one inlet for a chemical decomposition reagent-containing liquid, at least one inlet for a polyurethane material, and at least one outlet for an organically modified carbamate, wherein the polyurethane material and the liquid can be contacted in a reaction zone of the reactor and converted to at least one organic compound selected from organically modified carbamates; At least one inlet for a chemical decomposition reagent, at least one inlet for a water-containing liquid, an organically modified carbamate, and ２ and at least one outlet for a gas stream, wherein the organically modified carbamate and the water-containing liquid can be contacted in a reaction zone of the hydrolysis device, and the CO formed ２ at least one hydrolysis unit capable of directing a gas stream through said outlet, said inlet for organically modified carbamates fluidly connected to said outlet for organically modified carbamates in said chemical decomposition unit; 15. Apparatus according to claim 14, characterized in that it comprises a unit for hydrolysis comprising:

16. The at least one optionally scrubbed CO ２ The unit for reducing the gas stream (31, 31a) comprises: ２ 16. The device according to any one of claims 13 to 15, characterized in that it is an electrolysis unit equipped with a gas diffusion electrode or a reverse water gas shift reactor for reduction.

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