Method for producing phosgene by using carbon dioxide generated by recycling useful materials

Abstract

The invention relates to a method for producing phosgene, in particular to a method for producing organic isocyanate by reacting phosgene with an organic amino compound. In the process, at least one gas stream of carbon dioxide, which has been formed by the hydrolysis of organic modified carbamates, and which may have been released by secondary components, is reduced to carbon monoxide. The generated carbon monoxide reacts with chlorine in phosgene synthesis to generate phosgene. The organically modified carbamates used in the method can preferably be obtained from the chemical decomposition of scrapped polyurethane materials, in particular using alcohols, ammonia or amino alcohols as chemical decomposition agents.

Description

[0001] The invention relates to a process for producing phosgene, in particular for the reaction of phosgene with organic amino compounds to give organic isocyanates, wherein at least one carbon dioxide gas stream formed by the hydrolysis of the organic carbamate and optionally released from secondary components is converted into carbon monoxide and the resulting carbon monoxide is converted into phosgene with chlorine in a phosgene synthesis.

[0002] Carbon dioxide (hereinafter also referred to as CO 2 ) Recycling into the value chain is a contribution to sustainable development. In the past, efforts have been made to make carbon dioxide usable, for example, for the production of carbon monoxide (hereinafter also referred to as CO).

[0003] The document EP 3744812 B1 states that CO formed in the pyrolysis of useful polyurethane materials 2 and CO formed in the combustion of useful polyurethane materials 2 By CO 2 In CO 2 The CO obtained reacts with chlorine to form phosgene, which is used as a starting material for polyurethane and is used to prepare organic isocyanates. 2 It must undergo complex cleaning methods before it can be used for electrochemical CO 2 reduction.

[0004] In the process of recycling carbon dioxide for the production of isocyanate compounds, according to document WO 2021 / 089737A1, CO from an external source (e.g. combustion of useful polyurethane materials) is used. 2 In the reverse water gas shift reaction (R WGS reaction), CO is converted into CO with hydrogen. Here, CO is converted into CO with hydrogen with hydrogen in the reverse water gas shift reaction (R WGS reaction). 2 Cleaning must also be done in a sophisticated manner.

[0005] CO 2 Another option for recycling the production of isocyanate compounds is provided by the method of document WO 2022 / 167387 A1. Here, the CO formed during steam reforming is 2 and from other CO 2 Additional CO from the source 2 is recycled into the steam reforming process. 2 Sources are, for example, CO obtained in cement production or waste incineration. 2 CO from these sources 2 Before use in the steam reforming process, it also has to be cleaned in a complex manner.

[0006] One object of the present invention is to reduce the CO 2The process complexity of the process is exploited to make the process more economical and / or more environmentally friendly. Overall, the aim is to provide a method for the sustainable production and reuse of polyurethane materials.

[0007] Those skilled in the art understand the "sustainability" of a method based on the definition of sustainability (sustainable development) proposed by the United Nations in the Brundtland Report of the "World Commission on Environment and Development", that is, the implementation of current methods has the least possible impact, or no impact at all, on the ability of future generations to meet their needs, especially with regard to the use of resources such as fossil raw materials, and especially with regard to the protection of living space, such as the protection of the Earth's atmosphere.

[0008] The study found that CO formed in the hydrolysis of organic modified carbamate compounds 2 (especially CO formed from the hydrolysis of organic modified carbamates obtained from the chemical decomposition of polyurethane materials 2 ) has very high purity and can be used for reduction conversion to CO while providing lower levels of economic and / or environmental resource usage.

[0009] Therefore, the present invention first provides a method for producing phosgene (especially for preparing organic isocyanates), which is carried out by at least the following steps:

[0010] CO is produced by at least the following steps 2 Gas Flow:

[0011] providing at least one organically modified urethane;

[0012] Hydrolyze the at least one organic modified carbamate provided to form at least an organic amino compound and CO 2 ;

[0013] Separation of the formed CO 2 To obtain at least one CO 2 airflow;

[0014] The CO is preferably cleaned by at least one cleaning method selected from condensation, adsorption, catalytic gas cleaning or gas scrubbing. 2 a gas stream 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 cleaned carbon dioxide;

[0015] The at least one optionally cleaned CO 2 CO in airflow 2 Reduction to carbon monoxide;

[0016] Phosgene is synthesized from at least the carbon monoxide obtained by the reduction and chlorine.

[0017] For example, documents DE 197 19084 A1, EP 0 031 538 A2, WO 2022 / 171586 A1 and WO 2022 / 128871 A1 disclose that chemical decomposition of useful polyurethane materials can generate organic amines and polyols, and these compounds from useful polyurethane materials can be reused in the production of polyurethane materials.

[0018] In this case, one method of physically recycling the polyurethane material is, for example, alcoholysis or glycolysis, in which the urethane groups react with alcohols or glycols by transesterification or transcarbamate reaction, respectively:

[0019]

[0020] In addition, carbamate groups can react with amino groups to form ureidinyl groups:

[0021]

[0022] There is no information anywhere on CO2 generated during the hydrolysis of organically modified urethanes or during the chemical decomposition of polyurethane materials. 2 Description of the exhaust gases as being particularly suitable for reuse.

[0023] In the context of the present invention, a "polyurethane material" is an addition polymerization product (occasionally also referred to as a condensation polymerization product, although this is not entirely correct) obtained by reacting a polyfunctional isocyanate (=isocyanate component in the preparation of a polyurethane) and a polyol (=polyol component in the preparation of a polyurethane). Polyurethane materials generally contain not only the polyurethane base structures listed above, but also other structures, for example structures with urea bonds. The presence of such structures which deviate from the pure polyurethane base structure in addition to the polyurethane 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.

[0024] In the terminology of the present invention, the term isocyanate encompasses all isocyanates known to the person skilled in the art in connection with polyurethane chemistry, such as, in particular, toluene diisocyanate (TDI; produced from toluene diamine, TDA), diisocyanates and polyisocyanates of the diphenylmethane series (MDI; produced from diamines and polyamines of the diphenylmethane series, MDA), 1,5-pentyl diisocyanate (PDI; produced from pentane-1,5-diamine, PDA), hexamethylene 1,6-diisocyanate (HDI; produced from hexamethylene-1,6-diamine, HDA), isophorone diisocyanate (IPDI; produced from isophorone diamine, IPDA), and xylylene diisocyanate (XDI; produced from xylylene diamine, XDA). The expression "one isocyanate" of course also encompasses embodiments in which two or more different isocyanates (e.g. a mixture of MDI and TDI) are used for the production of the polyurethane product, unless expressly stated otherwise, for example by the wording "only one isocyanate". The whole of all isocyanates used to produce polyurethane products is referred to as the isocyanate component (of polyurethane foam). The isocyanate component includes at least one isocyanate. Similarly, the whole of all polyols used to produce polyurethane foam is referred to as the polyol component (of polyurethane foam). The polyol component includes at least one polyol.

[0025] In the terminology of the present invention, the term polyol includes all polyols related to polyurethane chemistry known to those skilled in the art, such as in particular polyether polyols, polyester polyols, polyether ester polyols and polyether carbonate polyols. The expression "polyol" certainly also encompasses embodiments in which two or more different polyols are used in the preparation of polyurethane foams. Therefore, if, for example, "polyether polyol" (or "polyester polyol" etc.) is mentioned hereinafter, the term certainly also encompasses embodiments in which two or more different polyether polyols (or two or more different polyester polyols etc.) are used in the preparation of polyurethane raw materials.

[0026] The term "organic modified carbamate" in the present invention refers to organic carbamate compounds. These include not only polyurethane materials but also preferably those organic modified carbamates formed in the chemical decomposition of polyurethane materials by reaction with chemical decomposition agents.

[0027] An "organic compound" contains at least one covalent carbon-hydrogen bond in its molecule. Accordingly, an organic amino compound is an organic substance which, as a chemical substance, contains at least one amino group and at least one covalent carbon-hydrogen bond in its molecule. Organic modified carbamates are similarly defined mutatis mutandis.

[0028] According to the present invention, "chemical decomposition" refers to the chemical conversion of polyurethane materials by cleaving the polyurethane polymer structure through ester exchange reactions (also called carbamate exchange reactions) or by forming urea groups (also called: carbonyldiimino groups, *-NH-C(=O)-NH-*).

[0029] The "chemical decomposition agent" refers to an agent that enters into a chemical reaction to chemically decompose the urethane bond as a reactive group of the polyurethane material.

[0030] In the context of a preferred embodiment of the method, the organic modified carbamate is provided by chemical decomposition of a polyurethane material. For the provision of the organic modified carbamate, it is sufficient in the context of the present embodiment when the organic modified carbamate is a direct process product of chemical decomposition of a polyurethane material. This means that for the implementation of the step of providing the organic modified carbamate, it is sufficient to simply obtain the organic modified carbamate from a storage container or in a feed pipeline in the case of raw material transportation. In this case, the phosgene producer, as the implementer of the process of the present invention, does not perform chemical decomposition of the polyurethane material to produce the organic modified carbamate himself, but only needs to ensure that the organic modified carbamate provided has been produced accordingly by the supplier through chemical decomposition and is its process product. Therefore, a preferred embodiment is characterized in that the organic modified carbamate provided is at least one direct process product of chemical decomposition of a polyurethane material, comprising at least the following method steps:

[0031] Polyurethane materials available

[0032] The provided polyurethane material is reacted with at least one chemical decomposition agent, 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 urethane.

[0033] In principle, the polyurethane material provided can be any polyurethane product, i.e. polyurethane foam or polyurethane product in so-called CASE applications. Polyurethane foam can be both soft foam and hard foam, preferably soft foam (e.g. from used mattresses, furniture pads or car seats). For polyurethane products from CASE applications, polyurethane elastomers, polyurethane adhesives and polyurethane coatings are preferred. Among all polyurethane products, soft polyurethane foam is particularly preferred. The polyurethane material provided is, for example, waste polyurethane material from corresponding scrapped polyurethane products (e.g. mattresses, seat cushions or insulation materials).

[0034] In addition, Isocyanate componentIn the case of polyurethanes, polyurethane materials based on isocyanates selected from the group consisting of toluene diisocyanate (TDI), diisocyanates 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 above isocyanates are preferred. In the case of the isocyanate component, polyurethane materials based on TDI or a mixture of TDI and MDI are particularly preferred. In the case of the isocyanate component, polyurethane materials based solely on TDI are very particularly preferred.

[0035] In addition, Polyol components In particular, polyurethane materials based on polyols selected from the group consisting of polyether polyols, polyester polyols, polyether ester polyols, polyether carbonate polyols or mixtures of two or more of the aforementioned polyols are preferred.

[0036] The provision of the polyurethane material preferably includes preparatory steps for subsequent reaction with a chemical decomposition agent. These relate in particular to mechanical comminution of the polyurethane material. These preparatory steps are known to those skilled in the art; for example, reference is made to the review by Simón, Borreguero, Lucas and Rodríguez in Waste Management 2018, 76, 147-171.

[0037] It has been found to be particularly advantageous when the provided polyurethane material has been subjected to an inertization treatment, which at least comprises the removal of gaseous oxygen contained in the vicinity of the polyurethane material and / or in its pores. The inertization treatment is particularly recommended when the polyurethane material is in the form of a powder, granules or foam. The inertization treatment of the provided polyurethane material before the reaction with the chemical decomposition agent can be used to reduce the CO obtained in the hydrolysis process. 2 The gas stream achieves a particularly high purity. For example, if the polyurethane material in foam form is not inerted, the CO obtained by hydrolysis 2 The high concentration of N 2 and especially O 2 , must be derived from CO in a highly complex manner 2 Remove from the air flow.

[0038] In a preferred embodiment, the inerting treatment further comprises the step of feeding at least one inert gas, in particular nitrogen, carbon dioxide, argon or helium, most preferably carbon dioxide, into the polyurethane material.

[0039] The inerting treatment of the provided polyurethane material is more preferably carried out by at least the following steps:

[0040] Degassing of polyurethane materials, applying no more than 960mbar in the container(abs) The first pressure of less than 700 mbar is applied to the container and the temperature does not exceed 120°C, and the gas in the head space gas phase is removed through the gas removal device. (abs.) , preferably 0.1mbar (abs.) Up to 100mbar (abs.) The reduced pressure is used as the first pressure, and the gas is removed by the gas removal device.

[0041] After the gas is removed, at least one inert gas (especially nitrogen, carbon dioxide, argon or helium, most preferably carbon dioxide) is injected to establish a pressure of preferably not more than 1.8 bar. (abs) pressure, more preferably atmospheric pressure.

[0042] The degassing properties and the overall inerting properties are described in document WO 2022 / 128871 A1, which is expressly incorporated herein in its entirety by reference.

[0043] Likewise, in the context of another embodiment of the present invention, in order to provide an organically modified carbamate, the above chemical decomposition conversion is carried out as a component step of a process in which the phosgene producer itself produces phosgene, and the resulting organically modified carbamate is then further hydrolyzed to form CO. 2 Therefore, a corresponding preferred embodiment of the method is characterized in that the CO 2 The gas stream (31) is generated by chemical decomposition of the polyurethane material, which comprises at least the following steps:

[0044] Provide polyurethane materials;

[0045] reacting the provided polyurethane material with at least one chemical decomposition agent, 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 organic modified carbamate;

[0046] Hydrolyze the previously formed organic modified carbamate to form at least an organic amino compound and CO 2 ;

[0047] The carbon dioxide formed is separated to obtain at least one CO 2 airflow.

[0048] In the context of the above-described embodiments of the invention, the hydrolysis step can be realized as a separate process step from the conversion of the polyurethane material and / or simultaneously in one step. In the simultaneous sequence, a mixture comprising a chemical decomposition agent and additionally sufficient water is used.

[0049] It is generally preferred when the provided organically modified carbamate is formed by reacting the provided polyurethane material with at least one chemical decomposition agent under the exclusion of oxygen, or is a direct process product of such a reaction. This means that the reaction is carried out in an inert gas atmosphere (especially in a nitrogen, carbon dioxide, argon or helium atmosphere, more preferably in a carbon dioxide atmosphere). It is also preferred that the oxygen of the chemical decomposition agent (water and chemical decomposition agent) used is removed by saturation with an inert gas. In this case, it is very particularly preferred when the provided polyurethane material is inerted as described above.

[0050] In a preferred embodiment, the provision of the organic modified carbamate is achieved by at least the following method steps:

[0051] Provide polyurethane materials;

[0052] reacting the provided polyurethane material with at least one chemical decomposition agent (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 urethane;

[0053] The composition obtained previously is mixed, without previously removing any water present in the composition, with an organic solvent in which the chemical decomposition agent previously used is not completely miscible, and phase separated to form a carbamate phase (containing the organic modified carbamate) and a solvent phase.

[0054] In this embodiment, the resulting carbamate phase is introduced into a hydrolysis step.

[0055] The organic solvent to be used should be incompatible with the chemical decomposition agent used for chemical decomposition. This means that under the conditions of the above mixing, there must be Miscibility gap , so that phase separation can be achieved. The organic solvent is more preferably selected from aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and a mixture of two or more of the above organic solvents.

[0056] In another preferred embodiment of the phosgene production according to the invention, the chemical decomposition is integrated as a process step, and it is particularly preferred to carry out the reaction of the polyurethane material to form the organically modified carbamate and the hydrolysis of the organically modified carbamate together in one process step.

[0057] Generally speaking, the water used for hydrolysis and the chemical decomposition reagent for chemical decomposition reaction in the inventive method are preferably used in superstoichiometric amounts, whether the chemical decomposition reaction is carried out alone or in combination with hydrolysis in one step. This means that the amount of water used for hydrolysis is theoretically sufficient to hydrolyze all polyurethane bonds in the provided polyurethane material, while releasing at least carbon dioxide and organic amino compounds. Similarly, the use of a superstoichiometric amount of chemical decomposition reagent means that its amount is theoretically sufficient to convert all polyurethane bonds in the provided polyurethane material into organic modified carbamates. In the case of using the mass ratio of water and chemical decomposition reagent preferred according to the present invention as described below, these two situations are usually the case.

[0058] The chemical decomposition conversion is preferably carried out in such a way that the mass ratio between the chemical decomposition agent (total amount) and water (total amount) on the one hand and the provided polyurethane material on the other hand (i.e. [m (chemical decomposition agent) + m (water)] / m (polyurethane product), m = mass) is in the range of 0.5 to 2.5, more preferably in the range of 1.0 to 1.3, wherein the mass of water is 2.0% to 10% of the mass of the chemical decomposition agent. The quantitative data on water here refer to the water added as a hydrolysis agent. In contrast, any amount of water emitted from the water vapor present in any case in the chemical decomposition agent used and / or the polyurethane material used is low. The moisture in the chemical decomposition agent used or the polyurethane material used refers to the trace amounts of moisture that may occur on an industrial scale. The mass of water here is further preferably 4.0% to 10.0% of the mass of the chemical decomposition agent used, especially preferably 5.0% to 7.0%.

[0059] The chemical decomposition reaction and the hydrolysis reaction can preferably be carried out in the following manner, wherein the polyurethane material is chemically decomposed using a chemical decomposition agent and water (preferably in the presence of a catalyst) within a temperature range of 130°C to 220°C, wherein the mass ratio of the chemical decomposition agent to water as one side and the polyurethane material as the other side is 0.5 to 2.5, and the mass of water is 4.0% to 10% of the mass of the polyurethane material.

[0060] In the case of chemical decomposition and hydrolysis being carried out jointly in one process step, it has been found to be particularly preferred not to add the water for hydrolysis immediately at the beginning of the reaction time, or at least not to add it all. It has been found to be useful to first mix only a small part of the total amount of water, i.e. 2% to 4%, if any, with the other reactants (i.e. at least the chemical decomposition agent and the polyurethane material), and to add the remaining or the entire amount of water during the further reaction time. The water for hydrolysis of the organic modified carbamate formed as an intermediate is added continuously or in intervals in batches, so that the boiling temperature of the reaction mixture is always kept within the specified range, in particular within the particularly preferred range of 165° C. to 185° C. The metering time of water is preferably in the range of 1.0 hour to 5.0 hours (depending on the boiling point of the chemical decomposition agent used). In a preferred embodiment, the mass ratio between the chemical decomposition agent (total amount) and the water (total amount) as one side and the provided polyurethane material as the other side (i.e. [m (chemical decomposition agent) + m (water)] / m (polyurethane product), m = mass) is in the range of 1.1 to 1.3. If the water is not added all at once but gradually as described above, this applies to the entire amount of water used.

[0061] In the case where the chemical decomposition and the hydrolysis are carried out together in one process step, the amount of water used is preferably 5.0% to 7.0% by mass of the chemical decomposition agent used; this is particularly true when the above-mentioned mass ratio [m (chemical decomposition agent + water) / m (polyurethane material)] is in the range of 1.0 to 1.3. If the water is not added all at once, but gradually as described above, this applies to the total amount of water used in this step.

[0062] In the case where the chemical decomposition and the hydrolysis are carried out together in one process step, it is not necessary to add all the water at the beginning. In this case, the above ranges for the amount of water based on the mass of the chemical decomposition reagent relate to the total amount of water added at the end of the reaction time. The same applies to the case where the chemical decomposition reagent is added gradually.

[0063] In particular, it is also possible that:

[0064] (I) firstly, the polyurethane material is mixed with a chemical decomposition agent alone or with the chemical decomposition agent and a first portion of water, and then

[0065] (II) Adding water or a second portion of water, especially only after the polyurethane material has gone into solution.

[0066] In this respect, the expression "goes into solution" does not necessarily mean that there is a "true" solution in the sense that there is a completely homogeneous mixture. It may well be the case that there is a "turbid" solution of the polyurethane material without departing from the scope of the present invention.

[0067] In the joint implementation of the chemical decomposition and hydrolysis in the above-mentioned steps (I) and (II), it is particularly preferred that water or a second portion of water is added continuously or in portions in step (II) so that the temperature of the liquid phase during step (II) differs from the temperature of the liquid phase in step (I) by a maximum of 20° C., preferably a maximum of 15° C., more preferably a maximum of 10° C., even more preferably a maximum of 5.0° C., very particularly preferably a maximum of 1.0° C. In this way, it is achieved that the temperature is always high enough to ensure the progress of the chemical decomposition reaction.

[0068] For example, the chemical decomposition in combination with the hydrolysis in one step is described in document WO 2022 / 171586 A1, which is expressly incorporated herein in its entirety by reference, using, for example, an alcohol having at least one hydroxyl group as the chemical decomposition agent.

[0069] For example, chemical decomposition with hydrolysis as a separate step is described in documents US 4,336,406 and WO 2020 / 260387 A1, each using the example of an alcohol having at least one hydroxyl group as a chemical decomposition agent. The documents are expressly incorporated herein in their entirety by reference.

[0070] The chemical decomposition can generally be carried out, optionally in combination with the hydrolysis, in any reactor known in the art for this purpose. Particularly suitable reactors for the chemical decomposition are stirred tanks (stirred reactors) and tubular reactors.

[0071] In another embodiment, it is particularly preferred to assist the chemical decomposition by using at least one catalyst as the reaction of the polyurethane material with the chemical decomposition agent (for example alone or in combination with the hydrolysis in one step). The catalyst used in this preferred embodiment is more preferably at least one compound selected from the group consisting of carbonates, bicarbonates, orthophosphates, monohydrogen orthophosphates, metaphosphates, hydroxides, organic amines (especially diethanolamine), organic metal compounds (especially tetrabutoxytitanium, tin octoate or dibutyltin dilaurate) or mixtures of two or more of the above catalysts. It is particularly preferred to use at least one metal salt selected from the group consisting of carbonates, bicarbonates, orthophosphates, monohydrogen orthophosphates, metaphosphates or mixtures of two or more of the above metal salts as catalyst.

[0072] Orthophosphate is orthophosphoric acid (H 3 PO 4 ) in which all protons have been eliminated (=PO 4 3- ). Monohydrogen orthophosphate is orthophosphate with two protons eliminated (=HPO 4 2- Metaphosphate is a condensation product of orthophosphoric acid and has [(PO 3 ) - ]n The empirical formula of , where n is a natural number (especially 3 or 4).

[0073] If a catalyst is used in the chemical decomposition step, it is preferably present in an amount of 0.1% to 3.5% by mass based on the mass of the provided polyurethane material.

[0074] If the catalyst is used in the form of an aqueous solution, the water used as solvent should also be taken into account in the quantitative data given above for water used in the hydrolysis, ie the amount of water to be additionally used in the hydrolysis (if necessary) should be reduced accordingly.

[0075] Furthermore, it is further preferred to perform the hydrolysis using at least one of the above-mentioned catalysts.

[0076] In another embodiment, the chemical decomposition (for example alone or in combination with hydrolysis in one step) is particularly preferably carried out as a reaction of the polyurethane material with at least one chemical decomposition agent selected from the group consisting of: (a) primary or secondary organic amines, (b) amino alcohols having primary or secondary amino groups or (c) alcohols having at least one hydroxyl group.

[0077] Suitable alcohols having at least one hydroxyl group as chemical decomposition agents are preferably at least one alcohol having at least two hydroxyl groups. In this case, it is particularly preferred that the chemical decomposition agent 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 above alcohols.

[0078] Suitable amino alcohols having a primary or secondary amino group as chemical decomposition agents are preferably at least one amino alcohol selected from ethanolamine, N-methylethanolamine, 3-amino-1-propanol.

[0079] Suitable primary or secondary organic amines as chemical decomposition agents are preferably at least one aliphatic primary or secondary organic amine. These primary or secondary amines are preferably monoamines and / or diamines. Ethylene-1,2-diamine, 1,4-diaminobutane, hexamethylene-1,6-diamine or a mixture of two or more thereof are particularly preferred as chemical decomposition agents for primary or secondary organic amines.

[0080] The chemical decomposition reaction of the polyurethane material with the chemical decomposition agent to form the organic modified carbamate is preferably carried out in the range of 140°C to 220°C, preferably 170°C to 200°C. This temperature is also observed to be preferred in the case where the conversion of the polyurethane material and the hydrolysis are carried out simultaneously in one step. There are no particular requirements for the pressure. The reaction can be carried out under reduced pressure or under increased pressure; for example, at 200 mbar (abs.) Up to 2000mbar (abs.) The pressure is preferably 500mbar (abs.)Up to 1500mbar (abs.) , more preferably 900 mbar (abs.) Up to 1300mbar (abs.) , especially at ambient pressure. In the context of the present invention, pressure figures are always expressed as absolute pressures, identified by the subscript "abs" after the pressure unit (e.g., an absolute pressure of 900 mbar is referenced as "900 mbar (abs) ”).

[0081] In another embodiment, preferred is a process wherein the temperature of the obtained carbon dioxide gas stream is from 140°C to 220°C, preferably from 170°C to 200°C.

[0082] The obtained carbon dioxide is cleaned to remove secondary components, in particular nitrogen, oxygen, chemical decomposition agents (e.g. diethylene glycol), sulfides, dust and water, preferably by at least one cleaning method selected from condensation, adsorption, catalytic gas cleaning or gas scrubbing, to obtain cleaned carbon dioxide (31a). However, the CO obtained by the method of the present invention 2 The gas stream has excellent purity for further use in CO 2 Optionally, during the CO 2 Before the reduction of CO 2 Post-processing of the CO requires only a few cleaning steps. These steps can be carried out simply and efficiently. 2 CO obtained from hydrolysis in the gas stream 2 Contains chemical decomposition agents, organic amino compounds formed during chemical decomposition, and polyols as major secondary components. These components can be 2 The cleaning (4) of the gas stream (31) is effective to remove at least CO 2 The gas stream is guided through a plurality of condensers and cooled, wherein the organic and aqueous components present as minor components in the gas stream are condensed and separated off in liquid form, and at the end of the cleaning (4), the cleaned CO 2 The gas stream (31a) is fed to the reduction (6) to form carbon monoxide.

[0083] CO is achieved when condensation and gas scrubbing are combined 2 Further improvement of the cleanliness of the air flow.

[0084] The carbon monoxide required for the synthesis of phosgene is obtained by reacting at least one optionally cleaned CO 2 CO in the gas stream (31, 31a) 2 In another preferred embodiment of the process, CO 2 The reduction is achieved by at least one method selected from the following:

[0085] A) electrochemical reduction of carbon dioxide, preferably using electricity produced from renewable energy sources,

[0086] B) methane (preferably biomethane) and steam at a temperature of at least 500°C, with the addition of at least CO 2 and convert it into carbon monoxide in the reforming process with the provision of heat energy,

[0087] C) In the reverse water gas shift (R WGS) reaction zone, hydrogen and CO 2 Converted into carbon monoxide.

[0088] Those skilled in the art understand "renewable energy" to mean inexhaustible energy, such as wind energy, hydropower, bioenergy (e.g., converting biogas or biomass into electrical energy) or solar energy. Therefore, suitable renewable energy is most preferably wind energy, solar energy, hydropower or a mixture thereof.

[0089] In implementing CO 2 When reducing (6), it is preferred to use the optionally cleaned CO 2 The gas stream is introduced into an electrolyser and reduced to carbon monoxide at electrodes, preferably gas diffusion electrodes (more preferably using electricity generated from renewable energy sources).

[0090] For example, CO 2 The electrolysis may be a high temperature electrolysis operating at a temperature greater than 600°C, whereby synthesis gas may be produced by adding water. High temperature electrolysis is known in principle and is commercially available, for example from Haldor Topsoe, High temperature electrolysis forms oxygen at the anode. One disadvantage of high temperature electrolysis is its poor scalability, so for larger volumes of CO, for example more than 1 t / h of CO, low temperature electrolysis is currently still preferred.

[0091] If CO 2 The electrolysis is carried out at a temperature of less than 150°C.

[0092] In all CO 2 In electrolysis, CO 2 The gas is fed into the cathode space.

[0093] In the case of low temperature electrolysis, CO 2 In particular, it is converted into carbon monoxide and possibly hydrogen at the gas diffusion electrode. At the same time, O 2, or in some cases, chlorine can also be generated. If chlorine is generated at the anode, it can be fed to the phosgene synthesis and thus used as a further raw material for the production of isocyanates. For example, the person skilled in the art knows from the document WO 2021 / 069470 A that the implementation of CO 2 Electrodes and methods for electrochemical reduction. More preferably, CO 2 The electrochemical reduction is carried out by the method of WO 2021 / 069470 A. This document is expressly incorporated herein by reference in its entirety. In this preferred electrolytic method for producing carbon monoxide, carbon monoxide, optionally hydrogen and chlorine are obtained by electrochemical conversion of carbon dioxide and alkali chloride solution. This preferred electrolysis process is characterized in that carbon dioxide is electrochemically reduced in an aqueous solution containing alkali chloride as a cathode electrolyte at a gas diffusion electrode as a cathode, and at the same time, chlorine is generated by the anode in an aqueous solution containing alkali chloride as an anolyte, wherein the alkali metal salt of carbonic acid formed in the cathode liquid is selected from alkali carbonates, alkali bicarbonates or mixtures thereof, and then reacts with hydrogen chloride to generate carbon dioxide and alkali chloride, and the released carbon dioxide is returned to the cathode space of the gas diffusion electrode, and the generated alkali chloride is returned to the anode space and / or cathode space.

[0094] According to known principles, the MEA (Membrane Electrode Assembly) concept can also be used for low-temperature electrolysis. In this case, a catalyst is applied to the membrane. An upstream gas diffusion layer regulates the transport of gases and liquids. This can be achieved on both the anode and cathode sides. It is also possible to place gas diffusion electrodes in direct contact with the membrane.

[0095] The gas diffusion electrodes used can be installed in the electrolysis cell in a zero-gap or limited-gap manner. 2 The preferred installation method of is expressly incorporated into this document in its entirety by reference.

[0096] The cathode space, or the gas diffusion electrode stored therein, can be supplied with excess CO 2 By "excess" is meant that the amount of carbon dioxide introduced exceeds that necessary for stoichiometric conversion based on the flowing current. 2 , CO and H 2 The composed gas mixture thus leaves the cathode space.

[0097] A suitable reforming process is described in PCT application number PCT / EP2022 / 052267, in which methane (preferably biomethane) and steam are converted to carbon monoxide at a temperature of at least 500°C with the addition of at least said carbon dioxide and the provision of thermal energy, which is expressly incorporated herein by reference in its entirety. The process involves converting methane, steam and CO2 The preparation of carbon monoxide for preparing phosgene for synthesizing organic isocyanates comprises at least the following steps:

[0098] Carbon monoxide is synthesized in a reforming process in which methane and steam are heated at a temperature of at least 500°C with the addition of at least CO 2 and converting it into a product gas containing carbon monoxide under the condition of providing heat energy;

[0099] The carbon monoxide-containing product gas obtained from the above synthesis is cleaned to obtain carbon monoxide by removing at least CO 2 , and optionally additionally by at least one removal selected from the group consisting of removal of water, removal of hydrogen, or a combination thereof;

[0100] The CO added to the reforming process is provided 2 , at least from the CO 2 of removal,

[0101] The condition is

[0102] 1) The heat energy supplied to the reforming process for the synthesis of carbon monoxide is provided by at least one method selected from the group consisting of: (i) combustion of a hydrogen-containing fuel produced by renewable energy, (ii) combustion of a methane-containing fuel from a biogenic source, (iii) conversion of electrical energy produced from renewable energy into thermal energy; or

[0103] 2) From other CO 2 Source additionally supplies CO 2 , to provide the CO added to the synthesis in the above reforming process 2 ;or

[0104] 3) Choose a combination of options 1) and 2) above.

[0105] A useful methane source for the reforming process is more preferably methane from a biological source. "Methane from a biological source" (also called "biomethane") is understood by a person skilled in the art to mean methane obtained industrially from biomass by methane fermentation, as opposed to fossil methane. As is well known, methane fermentation refers to the anaerobic degradation of organic matter by microorganisms. Methane from a biological source is produced, for example, in biogas plants, where both organic waste and renewable raw materials are fermented accordingly.

[0106] Additional CO used in step 2) above 2 The source is preferably at least one external CO 2 Source, which provides CO 2 is not emitted by the process of the present invention. For example, external CO 2 The source can be H in cement production or for the synthesis of ammonia. 2 CO obtained from production2 , CO formed in the exhaust gases of fuel combustion (e.g. waste incineration) 2 , or CO extracted from the air 2 In a preferred embodiment of the method of the present invention, the CO 2 Source of CO 2 is obtained by (i) at least one selected from cement production, 2 process gases or waste gases from production, incineration, and / or (ii) CO from air 2 This is achieved in part by absorption into an alkali metal hydroxide solution (e.g. potassium hydroxide solution). This results in the formation of potassium bicarbonate, which can then be decomposed back into CO by thermal decomposition. 2 and potassium hydroxide. The released CO 2 It is then fed to the reforming process for the synthesis of carbon monoxide. 2 Independently of the reforming process, CO can also be fed to A) (electrochemical reduction) or C) (R WGS reaction). 2 reduction.

[0107] In a particularly preferred embodiment of the process according to the invention, carbon monoxide is obtained from the CO used for phosgene synthesis, in particular for the synthesis of phosgene. 2 , through hydrogen and CO 2 The method is characterized in that at least one of the reverse water gas shift (R WGS) reactions produces carbon monoxide. Such an embodiment is described, for example, in document WO 2021 / 089737 A, which is expressly incorporated herein in its entirety by reference. According to the invention, a very particularly preferred embodiment of the method is characterized in that a hydrogen stream is provided and mixed with optionally cleaned CO 2 The gas streams are together converted by the principle of the reverse water gas shift reaction, particularly in the reaction zone, into a product gas comprising carbon monoxide and possible by-products.

[0108] A "reaction zone" is a portion of the reaction space where a chemical reaction (e.g., a reverse water gas shift reaction) takes place. A "reaction chamber" is a volume where co-reactants participating in a chemical reaction are brought together and the chemical reaction takes place. For a chemical reaction, this can, for example, be the volume of a container where reactants (e.g., carbon dioxide in an R WGS reaction) and co-reactants (hydrogen in an R WGS reaction) are present together and react in the reaction zone.

[0109] In this particularly preferred method, for the production of carbon monoxide, at least the following steps are particularly preferably carried out:

[0110] Feeding the provided hydrogen gas together with the carbon dioxide gas stream into the R WGS reaction zone, and reacting the reactants according to the principle of the R WGS reaction to generate a product gas mixture consisting of steam, CO and possible by-products (particularly low hydrocarbons, particularly preferably methane);

[0111] separating unconverted carbon dioxide from the gas mixture of the R WGS reaction obtained by separation, in particular by amine scrubbing, and recycling the unconverted carbon dioxide into the R WGS reaction;

[0112] separating the unconverted hydrogen from the R WGS reaction from the gaseous mixture of carbon monoxide and hydrogen obtained after separation, in particular using a cold box, and optionally recycling the hydrogen into the R WGS reaction;

[0113] The remaining carbon monoxide from the separation is fed to the phosgene synthesis.

[0114] The R WGS reaction is preferably carried out in the presence of at least one catalyst. The latter is more preferably selected from at least one compound in the following group:

[0115] (I)Formula A (1-w-x) A′ w A″ x B (1-y-z) B′ y B″ z O 3-δ Mixed metal oxides

[0116] in

[0117] A, A' and A" are each independently selected from: 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; and

[0118] B, B' and B" are each independently selected from: 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; and

[0119] 0≤w≤0.5; 0≤x<0.5; 0≤y≤0.5; 0≤z≤0.5 and -1≤δ≤1;

[0120] (II)Formula A (1-w-x) A′ w A″ x B (1-y-z) B′y B″ z O 3-δ A mixed metal oxide wherein A, A' and A" are each independently selected from the group consisting of 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; and B is selected from the group consisting of Cr, Mn, Fe, Bi, Cd, C o , 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; and

[0121] B' is selected from: Re, Ru, Rh, Pd, Os, Ir and / or Pt; and B" is selected from: 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;

[0122] and

[0123] 0≤w≤0.5; 0≤x≤0.5; 0≤y≤0.5; 0≤z≤0.5 and -1≤δ≤1;

[0124] (III) a mixture of at least two different metals M1 and M2 on a support, the support comprising an oxide of Al, Ce and / or Zr doped with a metal M3;

[0125] Wherein: M1 and M2 are each independently selected from: Re, Ru, Rh, Ir, Os, Pd and / or Pt; and

[0126] M3 is selected from: Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Hu, Er, Tm, Yb and / or Lu;

[0127] (IV) LO x (M (y / z) Al (2-y / z) O 3 ) z A mixed metal oxide; wherein

[0128] L is selected from: 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, H o , Er, Tm, Yb and / or Lu; and

[0129] M is selected from: Ti, Zr, Hf, V, Nb, Ta, Cr, M o , W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Zn, Cu, Ag and / or Au; and

[0130] 1<x≤2;0<y≤12;and 4≤z≤9;

[0131] (V) LO(Al 2 O 3 ) z A mixed metal oxide; wherein

[0132] L is selected from the group consisting of: 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; and

[0133] 4≤z≤9;

[0134] (VI) an oxidation catalyst containing Ni and Ru;

[0135] (VII) a metal M1 and / or at least two different metals M1 and M2 on and / or in a support, wherein the support

[0136] is a carbide, oxycarbide, carbonitride, nitride, boride, silicide, germanide and / or selenide of metal A and / or B; wherein:

[0137] M1 and M2 are each independently selected from: 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; and

[0138] A and B are each independently selected from: 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

[0139] The reaction products 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 ≥ 700°C.

[0140] In another embodiment, the hydrogen stream provided for the R WGS reaction is preferably obtained by electrolyzing water to generate hydrogen and oxygen. The production of hydrogen by water electrolysis is an electrochemical conversion of water. Water is decomposed into hydrogen and oxygen using electrical energy here. A known process is proton exchange electrolysis (PEM electrolysis), described, for example, in EP 3489394 A. A further method is alkaline water electrolysis. The two methods differ particularly in process parameters, such as temperature, pressure and pH. However, both methods produce target products water and oxygen. The electrolysis of water can be carried out with prior art devices. Industrial systems for alkaline water electrolysis and PEM electrolysis are known and commercially available. The principle of the electrolysis of water is described by way of example in Chapter 6.3.4 of "Elektrochemische Verfahrenstechnik" [Electrochemical process technology] (2003 Wiley-VCH-Verlag; ISBN 3-527-29958-0) by Volkmar M. Schmidt.

[0141] It is particularly preferred that, when water electrolysis (5) is used to provide the hydrogen stream, it is carried out using electricity generated from renewable energy, in particular renewable energy in the form of wind energy, solar energy or hydro energy.

[0142] If necessary, from CO 2 The carbon monoxide obtained in the reduction of is cleaned to remove any by-products present therein and used for phosgene synthesis. The phosgene synthesis is carried out by reacting at least chlorine and carbon monoxide, wherein the reacted carbon monoxide is at least from CO 2 The reduced carbon monoxide is produced and phosgene is discharged.

[0143] The carbon monoxide is preferably cleaned before use in phosgene synthesis by at least the following steps:

[0144] Remove water,

[0145] removing unconverted carbon dioxide from the gas mixture obtained by removing water, in particular by amine scrubbing, and recycling the unconverted carbon dioxide into the carbon dioxide reduction of the process according to the invention,

[0146] Any hydrogen present is removed from the gas mixture obtained after removal of unconverted carbon dioxide, in particular using a cold box.

[0147] In a further preferred embodiment of the process, the carbon dioxide is separated off after water has previously been separated from the carbon monoxide-containing product gas. For this purpose, the carbon monoxide-containing product gas is first fed to a water removal unit, in which the water is separated off, and the dry carbon monoxide-containing product gas obtained after the water separation is fed to a CO removal unit. 2 Removal unit, in which CO2 In the water removal unit, the water is separated off, for example by cooling the carbon monoxide-containing gas and separating the water, for example as condensate.

[0148] Here, "amine scrubbing" means in particular the basically known scrubbing by the principle of chemical absorption using amines, such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) or diethylene glycolamine (DGA), which enables a high-purity purified gas mixture to be achieved even at relatively low pressures in the absorption column.

[0149] A preferred variant of the method of the present invention is a method in which the carbon monoxide-containing gas (preferably from which water and CO have been removed) is 2 ) was introduced into H 2 -CO separation unit, in which hydrogen is separated. This forms at least one gas stream, wherein the gas at 25° C. and 1013 mbar contains at least 95% by volume of carbon monoxide, more preferably at least 99% by volume of carbon monoxide. The introduced product gas is preferably firstly separated from the H 2 The carbon monoxide is separated into two gas streams in a -CO separation unit. This produces one gas in the form of a gas stream containing at least 95% by volume (preferably at least 99% by weight) carbon monoxide, and another gas in the form of a gas stream having hydrogen as its main component as well as carbon monoxide and methane. The other gas is also referred to as H 2 The tail gas separated from the CO or (if there is no tail gas treatment) is called the final gas. 2 -CO separation unit is called cold box. 2 The hydrogen-containing tail gas separated from the CO-CO can be subjected to subsequent tail gas treatment to concentrate hydrogen. The process of tail gas treatment provides a gas rich in hydrogen in the form of a gas stream and another gas in the form of a gas stream containing a mixture of CO, methane and a smaller amount of hydrogen than the gas rich in hydrogen - called tail gas or final gas from tail gas treatment.

[0150] In order to provide the chlorine for the efficient phosgene synthesis in the present embodiment, the person skilled in the art will be very familiar with the production of chlorine from electrochemical oxidation by electrolysis of hydrochloric acid using gas diffusion electrodes (also known as HCl ODC electrolysis process (ODC=oxygen consuming electrode); suitable electrolysis cells are described in US, 6022,634 A, WO 03 / 31690 A1), the production of chlorine by diaphragm electrolysis of hydrochloric acid (see EP 1 103 636 A1), the production of chlorine by thermal catalytic gas phase oxidation (see WO 2012 / 025483 A2), the production of chlorine by chlor-alkali electrolysis (see WO 2009 / 007366 A2). The contents of the above documents relating to the production of chlorine are expressly incorporated herein in their entirety by reference. In a preferred variant of this embodiment of the method, the chlorine required for the phosgene synthesis is produced by electrolysis, in particular by electrochemical oxidation of hydrochloric acid electrolysis using gas diffusion electrodes, by electrochemical oxidation of hydrochloric acid diaphragm electrolysis, or by electrochemical oxidation of chlor-alkali electrolysis. In this case, in turn, it is particularly preferred that the electrochemical oxidations are each carried out using electricity generated from renewable energy sources, in particular from renewable energy in the form of wind energy, solar energy or hydroelectric power.

[0151] In a particularly preferred embodiment of the process, the phosgene formed by phosgene synthesis is used in a further step for producing organic isocyanates, wherein the phosgene from the phosgene synthesis is reacted with at least one organic amino compound, in particular with an organic amino compound obtained in the 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.

[0152] Usually, in this embodiment, those methods of the invention are preferred in which the organic isocyanate obtained contains at least two isocyanate groups. For this purpose, the reactant used in the synthesis is again preferably an organic amino compound having at least two amino groups, especially an organic amino compound obtained in the hydrolysis of the organic modified carbamate.

[0153] More preferably, the obtained organic isocyanate contains at least two isocyanate groups and has a molar mass of not more than 1000 g / mol, in particular not more than 800 g / mol.

[0154] The organic amine used is particularly preferably selected from toluenediamine (TDA), methylenebis(aniline) (MDA) (preferably in turn selected 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, wherein TDA, MDA or mixtures thereof, in particular TDA or MDA obtained from the hydrolysis of organically modified urethanes, are very particularly preferred organic isocyanates.

[0155] The organic isocyanate obtained is particularly preferably selected from toluene diisocyanate (TDI), diphenylmethylene isocyanate (MDI) (in turn preferably from 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate or mixtures thereof), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)benzene (XDI) or cyclohexyl diisocyanate (CHDI) or mixtures thereof, with TDI, MDI or mixtures thereof being very particularly preferred organic isocyanates.

[0156] Furthermore, in embodiments of the synthesis of organic isocyanates, it is preferred that hydrogen chloride is additionally generated together with the organic isocyanate. Again, this hydrogen chloride is preferably fed as a reactant to the preparation of chlorine for the phosgene synthesis. The necessary removal and purification of the hydrogen chloride formed during the production of isocyanates can be carried out by oxidation with oxygen to chlorine and water in a thermocatalytic gas phase oxidation reaction or optionally using O from water electrolysis. 2 to complete.

[0157] Another alternative method for using hydrogen chloride as a reactant for producing chlorine is to react hydrogen chloride with water to form hydrochloric acid, which is then electrochemically oxidized to form chlorine and optionally hydrogen. Such aqueous hydrochloric acid is particularly suitable for the hydrochloric acid electrolysis using gas diffusion electrodes, hydrochloric acid diaphragm electrolysis or chlor-alkali electrolysis described above. The O required for hydrochloric acid electrolysis using gas diffusion electrodes 2 It can be obtained by water electrolysis.

[0158] The hydrogen chloride produced in the production of isocyanates can also be converted into hydrochloric acid after purification and absorption in water. The produced hydrochloric acid is sold on the market for various purposes.

[0159] In a particularly preferred embodiment of the present method, the following operations are also performed:

[0160] Synthesis of phosgene by reaction of at least chlorine and carbon monoxide previously obtained after cleaning of the carbon monoxide-containing product gas from step c);

[0161] preparing isocyanates by reacting the phosgene obtained with at least one organic amine to form at least one organic isocyanate compound and hydrogen chloride;

[0162] The hydrogen chloride formed during the production of isocyanates is separated and purified and subsequently subjected to an oxidation reaction selected from:

[0163] - the formation of chlorine and water by thermocatalytic gas-phase oxidation of hydrogen chloride with oxygen, optionally with oxygen from water electrolysis,

[0164] - reaction of hydrogen chloride with water to form hydrochloric acid, followed by electrochemical oxidation of the hydrochloric acid to form chlorine and optionally hydrogen;

[0165] And, after the oxidative conversion of the hydrogen chloride, the chlorine formed is fed to the phosgene synthesis, while optionally an additional amount of chlorine from chlor-alkali electrolysis is supplied to the phosgene synthesis.

[0166] In a further step of the process, the organic isocyanate obtained can optionally be reacted with at least one organic compound having at least two hydroxyl groups, in particular with at least one polyester polyol or polyether polyol, to form a polyurethane material.

[0167] The polyurethane materials produced accordingly are in the form of, for example, foams, coatings, insulating compounds and components of commercial products. At the end of their service life, they can be provided again as polyurethane materials in the method according to the invention.

[0168] The present invention also provides CO 2 In the reduction reaction (i.e., reduction of C0 2 ) for use in producing carbon monoxide for phosgene production, the CO 2 It is the direct product of a process comprising at least the step of hydrolyzing at least one organically modified carbamate.

[0169] The corresponding embodiments of the method according to the invention also apply mutatis mutandis to this subject matter of the invention.

[0170] The present invention further provides the use of carbon monoxide for phosgene production, wherein the carbon monoxide comprises at least CO 2 (which has been prepared by hydrolyzing at least one organic compound selected from organically modified carbamates) is a direct product of a reduction reaction process.

[0171] The corresponding embodiments of the method according to the invention also apply mutatis mutandis to this subject matter of the invention.

[0172] The present invention further provides a phosgene production device, which comprises

[0173] At least one for providing CO 2 air flow unit, the CO 2 The gas stream is the direct product of a process comprising at least a step of hydrolyzing at least one organic compound selected from organically modified carbamates, wherein the unit comprises at least one 2 CO in air flow 2 export; and

[0174] Optionally at least one for cleaning CO 2a unit for removing secondary components from a gas stream, comprising at least one unit from the group formed by a condensation unit, an adsorption unit, a gas scrubbing unit or a catalytic gas cleaning unit, wherein the unit for cleaning CO 2 The gas flow unit has at least one 2 The gas stream is used as the CO to be cleaned 2 The gas flow inlet is connected to the CO 2 CO of the unit gas flow 2 outlet fluid connection, and wherein the CO 2 The gas flow unit has at least one for cleaning the CO 2 outlet for airflow; and

[0175] at least one for providing at least one optionally cleaned CO 2 A unit for reducing a gas stream to carbon monoxide, comprising at least one 2 The inlet of the gas stream, which optionally passes through at least one for cleaning CO 2 air flow unit, and for providing CO 2 at least one outlet of the unit for gas flow is fluidly connected and includes at least one outlet for carbon monoxide;

[0176] At least one phosgene production unit comprising

[0177] at least one inlet for chlorine gas, fluidly connected to a source of chlorine gas, and

[0178] at least one inlet for carbon monoxide and a channel for reducing said CO 2 at least one outlet fluidly connected to the unit for the flow of carbon monoxide;

[0179] At least one outlet for phosgene.

[0180] Fluid connection is understood to mean means which connect device components to one another and by which a substance, which may be in any material state, can be transferred as a material flow from one device component to the next, for example an inlet in the form of a pipeline. The expression "fluidically connected" means that the specified device components are connected to one another via a fluid connection.

[0181] "Reaction space" refers to the volume of a device in which the co-reactants participating in a chemical reaction are present together and in which the chemical reaction occurs. For a chemical reaction, this can be, for example, the volume of a vessel or container in which the co-reactants are present together and will react.

[0182] A preferred embodiment of the device is suitable for carrying out chemical decomposition conversion and hydrolysis simultaneously in one step, characterized in that the device for providing CO 2The unit for the gas stream comprises a unit for hydrolyzing at least one organic compound, comprising

[0183] at least one hydrolysis device comprising at least one inlet for a chemical decomposition agent, at least one inlet for a liquid containing water, at least one inlet for a polyurethane material and at least one inlet for CO 2 outlet of the gas stream, wherein the organic matter and the liquid can contact in the reaction zone of the hydrolysis unit and the CO formed 2 Air flow may be discharged through the outlet.

[0184] Another preferred embodiment of the device is suitable for chemical decomposition conversion and hydrolysis to be carried out separately, characterized in that the device for providing CO 2 The unit of the gas stream comprises a unit for hydrolyzing at least one organic compound, comprising:

[0185] at least one chemical decomposition device comprising at least one inlet for a liquid containing a chemical decomposition agent, at least one inlet for a polyurethane material and at least one outlet for an organically modified carbamate, wherein the organic material and the liquid can be contacted in a reaction zone of the reactor and converted into at least one organic compound selected from the group consisting of organically modified carbamates; and

[0186] at least one hydrolysis device comprising at least one inlet for a liquid containing water, at least one inlet for an organically modified carbamate and at least one inlet for CO 2 The outlet of the gas stream, wherein the organic modified carbamate and the liquid containing water can contact in the reaction zone of the hydrolysis unit to form CO 2 The gas flow may be directed only through said outlet; wherein the inlet for the organically modified carbamate is fluidly connected to the outlet for the organically modified carbamate in the chemical decomposition reactor.

[0187] In the context of this embodiment, it is also preferred that the unit for hydrolyzing at least one organic compound additionally comprises at least one separation device, wherein the outlet of the organic modified carbamate from the chemical decomposition device is connected to the inlet fluid of the separation device, and the separation device has at least one inlet for an organic solvent that is not completely miscible with the previously used chemical decomposition reagent, which is connected to the source fluid of the organic solvent, and comprises at least one outlet for the carbamate phase, which is connected to the inlet fluid of the hydrolysis device. The separation device is arranged so that the composition obtained in the chemical decomposition, which includes at least at least one organic modified carbamate, can be contacted with an organic solvent that is not completely miscible with the previously used chemical dissolution reagent, and after mixing and contacting, can be phase-separated into a carbamate phase (containing the organic modified carbamate) and a solvent phase; 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.

[0188] In another preferred embodiment of the device, a method for reducing at least one optionally cleaned CO is provided. 2 The unit of the gas flow (31, 31a) is a unit having a gas flow for CO 2 Reduced gas diffusion electrode electrolysis unit or reverse water gas shift reactor.

[0189] The present invention is implemented through the following embodiments 1 to 4 and combined with Figure 1 and Figure 2 The present invention will be described in detail, but the present invention is not limited to these embodiments. Figure 1 and Figure 2 In the following reference numerals, the following have the definitions on the right side, respectively:

[0190] 1 Chemical decomposition, here: glycolysis

[0191] 1a CO from chemical decomposition 2 Airflow (glycolysis)

[0192] 1b Chemical decomposition agent (here: diethylene glycol (DEG)) is added to make up for the loss

[0193] 1c Polyols from chemical decomposition

[0194] 1d CO from chemical decomposition combined with hydrolysis 2 Gas flow (here: hydroalcoholization)

[0195] 1e H 2 O+catalyst Na 2 CO 3 For chemical decomposition in combination with hydrolysis (here: hydroalcoholysis)

[0196] 2 Hydrolysis

[0197] 2a CO from hydrolysis 2 Airflow hydrolysis

[0198] 2b TDA from hydrolysis

[0199] 2c H for hydrolysis 2 O

[0200] 3 Chemical decomposition in combination with hydrolysis (here: hydroalcoholysis)

[0201] 3a Polyol solvent from hydroalcoholysis

[0202] 4 Solvent extraction

[0203] 4a Organic amino compounds (here: TDA) / organically modified urethanes from solvent extraction

[0204] 4h 2 O supplement to replace losses

[0205] 4c Polyols toluene from solvent extraction

[0206] 4d Polyols and solvents from solvent extraction

[0207] 5. Solvent Evaporation

[0208] 5a Toluene from solvent evaporation

[0209] 5b Cyclohexane solvent from 5

[0210] 5c For replacement of lost solvent

[0211] 5d Polyol

[0212] 6 Polyol Production

[0213] 6a Polyols from polyol production

[0214] 6b Residue Emissions

[0215] 7 Amine Cleaning

[0216] 7a Organic amino compounds from amine cleaning (here aTDA)

[0217] 7b Chemical decomposition agent from amine cleaning (DEG in this case)

[0218] 7c Residue

[0219] 7d H from amine cleaning 2 O

[0220] 7f H from amine purification 2 O

[0221] 8 Isocyanate production

[0222] 8a TDI

[0223] 8b HCl from isocyanate production

[0224] 9 Phosgene production

[0225] 9a Phosgene

[0226] 10 HCl Recovery

[0227] 10a Chlorine from HCl recovery

[0228] 11 PU foam production

[0229] 15 CO process gas processing: cooling, drying, CO 2 Removal (amine washing) and H 2 -CO separation

[0230] 15a from H 2 -CO separation of H 2

[0231] 15b from H 2 -CO separated from CO

[0232] 15c from CO 2 CO removed 2

[0233] 20 H 2 Production

[0234] 20a H from water electrolysis 2

[0235] 20c is used to replenish the H lost in water electrolysis 2 O

[0236] 30 by CO 2 The reduction of CO(CO 2 Electrolysis or R WGS)

[0237] 30a from CO 2 The reduced CO product gas stream

[0238] 40 CO 2 compression

[0239] 40a Compressed CO 2

[0240] 41 CO 2 Processing (CO from chemical decomposition 2 )

[0241] 41a Processed CO from chemical decomposition 2

[0242] 41b CO from 41 2 Emission Flow

[0243] 41c CO from 44 2 Emission Flow

[0244] 44 CO from hydrolysis 2 Processing

[0245] 44a CO purified from hydrolysis 2

[0246] 45 CO 2 Post-treatment of hydrolysis

[0247] 45a Purified CO from post-treatment of hydroalcoholysis 2

[0248] 45b CO from post-processing 45 2 emission

[0249] 46 CO 2 Storage (optional)

[0250] 52 Production of polyurethane materials (here: PU foam production)

[0251] 52a Polyurethane materials for the market

[0252] 54 Market / valuable material collection / separation

[0253] 54a Recycled PU foam

[0254] 60 Provision of polyurethane materials (here: PU foam preparation and inertization)

[0255] 60a Polyurethane material (here: TDI-based PU foam)

[0256] 70 R WGS Heating - Electricity or Biogas or H 2 Example

[0257] Example 1 Figure 1 ):

[0258] Overall process for the production of low-emission toluene diisocyanate (TDI), CO production via R WGS heated with biogas, Cl production via thermal catalytic gas phase oxidation (Deacon) of HCl 2 HCl recovery and H recovery from water electrolysis 2Provided is a method for preparing a CO 2-polymerized polyurethane material (TDI-based foam) by chemically cleaving polyurethane material (TDI-based foam) using diethylene glycol (PEG) as a chemical cleavage agent. 2 An overview of the hydrolysis of the resulting organomodified carbamates is provided, as well as being performed in a separate step.

[0259] 300 kg of polyurethane material 60a is provided in the form of polyurethane foam containing residual moisture and having a weight proportion of 33 wt % TDI and 67 wt % polyol ( Polyol 1108). Under an inert carbon dioxide atmosphere, 300 kg of diethylene glycol as a chemical decomposition agent was dissolved, and 5.5 kg of Na 2 CO 3 As a catalyst for chemical decomposition 1. Before the hydrolysis 2, the product mixture obtained by dissolution is introduced into a solvent extraction 4 with toluene as solvent with 227.1 kg of polyols, 251.1 kg of diethylene glycol and 119.6 g of TDA / organomodified carbamate, which is carried out similarly to the example in document WO2020 / 260387 A1. In the solvent phase obtained after phase separation, there are 1367 kg of toluene and 227.1 kg of polyols, which are transferred to the solvent evaporation 5, where the toluene solvent is almost completely separated from the polyols and recycled to the solvent extraction 4. The obtained polyols are further post-processed in the polyol production 6.

[0260] The carbamate phase obtained after phase separation in solvent extraction 4, containing 119.6 kg TDA / organically modified carbamate, was transferred to hydrolysis 2, where it was hydrolyzed in an inert carbon dioxide atmosphere, with a total of 16.5 kg of water added, and hydrolyzed at 180° C. for 2.5 hours. In general, a liquid composition containing 51.1 kg TDA and 300 kg diethylene glycol and CO was obtained. 2 Gas stream 2a. The liquid composition is transferred to an amine cleaning operation 7 where it is separated into 47.92 kg TDA 7a and about 300 kg diethylene glycol 7b and residual material 7c.

[0261] 3.7 kg / h CO is extracted from chemical decomposition 1 2 The gas stream 1a includes trace amounts of N 2 and O 2 , DEG, water, and CO 2 Post-treatment 41. The temperature of gas stream 1a is 180°C and the pressure is 1.01 bar. (abs) The gas stream 1a is cooled to 25°C by a heat exchanger, releasing a large amount of water and DEG in the process.

[0262] Subsequently, gas stream 1a was dried by zeolite and sub-gas stream 41a was purified with 0.3 kg CO; containing 3.4 kg CO 2 The tail gas stream 41a is fed to the compression operation 40 at 25°C.

[0263] The product from hydrolysis 2 is CO 2 Gas stream 2a, containing 33.2 kg / h of CO 2 , and trace amounts of N 2 and O 2 , DEG, water and toluene. The air flow temperature is 180°C and the pressure is 1.01 bar (abs) The gas stream 2a is cooled to 25°C by a heat exchanger, releasing a large amount of water and DEG in the process.

[0264] Subsequently, the cooled gas stream was dried by passing it through a zeolite and the sub-gas stream was treated with 2 kg / h of CO 2 Purified, contains 31.2kg CO 2 The tail gas stream 44a is fed to the compression operation 40 at 25°C.

[0265] From the compressor stage 40, a gas containing 34.6 kg / h CO at 30 bar and 40° C. is drawn off. 2 The continuous gas flow 40a is sent into the reaction space of R WGS in the form of R WGS and passes through CO 2 The CO production operation is carried out by reducing 30.

[0266] The R WGS reaction was run at 802 °C and the reaction temperature was maintained by the introduction and combustion of biogas. H 2 Heating or using electric heating. 34.6kg / h CO 2 and 1.57 kg / h H from water electrolysis 20 2 20a was introduced into the 2 The reduction of CO production was carried out in a 30R WGS reaction space, operating at a temperature of 802°C and 30 bar.

[0267] From the R WGS reaction, CO, H 2 O, unconverted CO 2 and unconverted H 2 and a product gas mixture 30a consisting of by-products (mainly a small amount of methane), and is cooled in the process gas cooling operation of the CO process gas processing operation 15.

[0268] The gas mixture is then sent to the process gas drying operation in the CO process gas processing operation 15 where a total of about 14.1 kg / h of water is removed. This water is sent to the water electrolysis 20.

[0269] A total of 1.57 kg / h of hydrogen was removed from the water electrolysis 20 and 14.13 kg / h of water was fed into the water electrolysis 20. This water consisted of circulating water from the process gas drying operation and newly added water.

[0270] The remaining gas mixture from the process gas drying operation is sent to the CO process gas processing operation 15 in the CO 2 Removal operation. Removal of CO by amine scrubbing 2 , the removed CO 2 15c is sent back to reduce CO 2 30 (R WGS reaction).

[0271] From the formation of CO 2 -Removal of CO from amine complexes 2 The energy comes from the process gas cooling operation described above, where the R WGS reactant gases are cooled. The CO 2 The gas is fed to the H in the CO process gas processing operation 2 -CO separation and removal. Use cold core box to remove H 2 -CO is separated, where H 2 The -CO gas mixture is cooled and hydrogen and CO are separated. The removed hydrogen (15a) is fed back to the R WGS reaction (31). 2 22.0 kg / h of CO 15b separated from the phosgene is fed to the phosgene synthesis 9. In the latter, the CO 15b reacts with 55.78 kg / h of chlorine 10a obtained from the HCl recovery process 10. The HCl gas is converted into chlorine by thermal catalytic gas phase oxidation (Deacon) of HCl from the isocyanate production 8. Optionally, O from the water electrolysis 20 2 It can be used for oxidation of HCl gas in Deacon process 10.

[0272] 77.78 kg / h of phosgene are drawn off from the phosgene synthesis 9 and react with 47.92 kg / h of toluenediamine 7a in the isocyanate production 8 to form 68.35 kg / h of toluene diisocyanate 8a.

[0273] The amount of HCl gas generated is 57.35 kg / h, which is cleaned by low-temperature distillation and fed to the Cl 2 In the thermal catalytic gas phase oxidation 10, HCl gas reacts with oxygen at about 300°C over a ruthenium oxide-based catalyst to produce chlorine and H 2 The required oxygen (12.57 kg / h) is drawn from the electrolyzed water 20.

[0274] The obtained toluene diisocyanate (68.35 kg / h) 8a was again mixed with 227.1 kg / h of polyol obtained in the process (essentially corresponding to Specifications of polyol 1108) 6a reaction, 295.44 kg / h of polyurethane material is generated in PU foam production 52.

[0275] After the polyurethane material is used in various applications in the market 54, it can be collected and recycled so that the polyurethane material obtained therefrom can be provided as a valuable material to chemical decomposition (1) after treatment and processing 60.

[0276] Hydrogen 20a is produced by using renewable energy in a water electrolysis 20 with a power of 0.088 MW. The water electrolysis 20 is an alkaline water electrolysis with a current density of 8 kA / m 2 , the cell voltage of each electrolysis element is 2 V. Here, 0.088 MW and 14.13 kg / h of water (16a+20c) are provided by the process gas cooling operation and the process gas drying operation (each from the removal of CO process gas processing operation 15) and externally. 1.57 kg / h of hydrogen and 12.56 kg / h of oxygen are drawn from the electrolyzed water.

[0277] By means of the method of the present invention, all raw materials of TDI-based PU materials, such as amines and polyols, are almost completely recovered, thus completing the value creation cycle.

[0278] The use of renewable energy in water electrolysis further reduces the generation of CO and Cl 2 The CO2 footprint of the produced phosgene is low, thus improving the sustainability of the TDI or PU materials generated.

[0279] Example 2 Figure 1 )

[0280] In addition to CO 2 Except for the implementation of reduction, this embodiment corresponds to embodiment 1.

[0281] Low temperature CO 2 Electrolysis as CO 2 The reduction of CO 2 The electrolysis was suitably carried out according to Example 1 of European Patent Application No. 18195279.7. The electrolysis was carried out at 1.2 bar (abs) 10 electrodes with an area of ​​1.6 m each were used. 2 The components are connected together to form an electrolytic cell. Electrolysis is performed at a cell voltage of 3.7 V and a current of 4.05 kA / m 2 The current density is 65%, with a current efficiency of 65% relative to CO. 0.239MWh of renewable energy, especially wind energy, is consumed, which is equivalent to 0.239MW of terminal power.

[0282] After drying, cleaning 41 and compression 40, 34.6 kg / h of CO 2 CO is fed at a pressure of 1.2 bar (abs) 2 Electrolysis 30. From CO 2 Electrolysis 30 produces 22kg / h CO concentration and 200kg / h CO 2 , 0.85kg / h 2 of gas mixture.

[0283] In addition, 19.36 kg / h of O was drawn from the anode space. 2 .

[0284] The gas mixture 30a produced by electrolysis 30 is sent to process gas processing operation 15 for drying operation and CO removal in the form of amine scrubbing. 2 Removal operation, unconverted CO 2 15c is separated from the mixture and returned to electrolysis 30. Removal of CO 2 The resulting gas consists of CO and H2 and is fed into a CO-H 2 Separation of CO and H in a cold box 2 22 kg / h of CO 15b and Cl from HCl recovery 10 2 10a generates phosgene 9a in phosgene production 9, which then reacts with TDA 7a from hydrolysis 2 and amine cleaning 7 to generate TDI 8a in isocyanate production 8.

[0285] Example 3 Figure 2 )

[0286] Figure 2 Overview of the overall process for reducing low-emission toluene diisocyanate (TDI), including R WGS reaction, chlorine production, PU production, use and utilization of polyurethane material waste, and recovery via hydrolysis and utilization of CO 2 Perform recycling of R WGS reactions.

[0287] 300 kg of polyurethane material 60a is provided in the form of polyurethane foam containing residual moisture and having a weight proportion of 33 wt % TDI and 67 wt % polyol ( Polyol 1108). In an inert carbon dioxide atmosphere, it was reacted with 300 kg of diethylene glycol as a chemical decomposition agent in a manner similar to that described in Example X of document WO XXX, and 5.5 kg of Na 2 CO 3 Combined chemical decomposition and hydrolysis (here: hydroalcoholysis) 3 was carried out with a total of 16.5 kg of water as catalyst. The product solution 3a and CO2 Airflow 1d.

[0288] After the reaction is finished, the product solution is transferred to solvent extraction 4 and mixed with 1866 kg of cyclohexane. The solvent phase 4d obtained after phase separation, containing 1866 kg of cyclohexane, 223.6 kg of polyols and 1.8 kg of residue, is transferred to solvent evaporation 5, where the cyclohexane solvent is almost completely separated from the polyols and recycled to solvent extraction 4. The generated polyols are further post-processed in polyol production 6 and separated from the residue 6b.

[0289] The amine-containing phase (TDA) obtained after phase separation and solvent extraction 4 contains 52 kg TDA water, salts and 300 kg DEG and is transferred to the amine cleaning operation 7 where it is separated into 47.92 kg TDA 7a, about 300 kg diethylene glycol 7b and residue 7c.

[0290] 37.4 kg / h CO was drawn from the hydrolysis 3 2 , containing trace amounts of N 2 and O 2 , DEG, water gas flow for 1 day, and send CO 2 Post-treatment 45. The temperature of the gas stream 1d is 180°C and the pressure is 1.01 bar (abs) The gas stream 1d is cooled to 25°C by a heat exchanger, releasing a large amount of water and DEG in the process.

[0291] Subsequently, gas stream 1d was dried by passing through zeolite and sub-gas stream 45b was dried with 2.8 kg CO 2 Purification, containing 34.6kg / h CO 2 The tail gas stream 45a is fed to the compression operation 40 at 25°C.

[0292] A gas containing 34.6 kg / h CO at 30 bar and 40° C. is drawn from the compressor stage 40. 2 The continuous gas flow 40a is sent into the reaction space of R WGS in the form of R WGS and passes through CO 2 The reduction 30 is performed for CO production operation.

[0293] The R WGS reactor 30 is operated at 802°C and the reaction temperature is maintained by introducing and burning biogas. H 2 Heating or using electric heating. 34.6kg / h CO 2 40a and 1.57kg / h H from water electrolysis 20 2 20a is introduced into the R WGS reaction space 30, which is carried out at a temperature of 802°C and 30 bar.

[0294] The product gas mixture 30a is composed of CO, H 2 O, unconverted CO 2 and unconverted H 2 and by-products (primarily small amounts of methane) are withdrawn from the R WGS reaction and cooled in the process gas cooling operation of the process gas processing operation 15 .

[0295] The gas mixture is then sent to a process gas drying operation in a process gas processing operation 15 where a total of about 14.1 kg / h of water is removed. The water is sent to water electrolysis 20.

[0296] A total of 1.57 kg / h of hydrogen 20a was removed from the water electrolysis 20 and 14.13 kg / h of water was fed into the water electrolysis 20. This water consisted of recycled water from the process gas drying operation described above and newly added water.

[0297] The remaining gas mixture from the process gas drying operation is fed to the CO in the process gas processing operation 15. 2 Removal operation. Removal of CO by amine scrubbing 2 , the removed CO 2 15c was fed back to the R WGS reaction 30.

[0298] From the formation of CO 2 -Removal of CO from amine complexes 2 The energy is derived from the process gas cooling operation in the process gas processing operation 15, wherein the R WGS reactant gas 30a is cooled. CO is released 2 The gas is fed to the H in the CO process gas processing operation 2 -CO separation. Use cold box for H 2 -CO separation, where H 2 The -CO gas mixture is cooled, and the hydrogen and CO are separated. The removed hydrogen 15a is fed back to the R WGS reaction 30. 2 22.0 kg / h of CO 15b separated from the phosgene is fed to the phosgene synthesis 9. In the latter, the CO 15b reacts with 55.78 kg / h of chlorine 10a obtained from the HCl recovery process 10. The HCl gas is converted into chlorine by thermal catalytic gas phase oxidation (Deacon) of HCl from the isocyanate production 8. Optionally, O from the water electrolysis 20 2 It can be used for oxidation of HCl gas in Deacon process 10.

[0299] 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 toluene diisocyanate 8a.

[0300] The obtained HCl gas of 57.35 kg / h was sent to the Cl 2 In the thermal catalytic gas phase oxidation 10, HCl gas reacts with oxygen at about 300°C over a ruthenium oxide-based catalyst to produce chlorine and H 2 The required oxygen (12.57 kg / h) is drawn from the electrolyzed water 20.

[0301] The obtained toluene diisocyanate (68.35 kg / h) 8a was again reacted with 223.6 kg / h of polyol obtained in the process (essentially corresponding to Specifications of polyol 1108) 6a reaction, 291.95 kg / h of polyurethane material is generated in PU foam production 52.

[0302] After the polyurethane material is used in various applications in the market 54 , it can be collected and recycled so that the polyurethane waste obtained therefrom is provided to the hydrolysis 3 after treatment and processing 60 .

[0303] Hydrogen 20a is produced using renewable energy in a water electrolysis 20 with a power of 0.088 MW. The water electrolysis 20 is an alkaline water electrolysis with a current density of 8 kA / m 2 , the cell voltage of each electrolysis element is 2V. Here, 0.088MW and 14.13kg / h of water are provided by the process gas cooling operation in the process gas processing (PGP) operation 15, the process gas drying operation in the PGP 15 and the outside. 1.57kg / h of H is drawn from the electrolyzed water 2 and 12.56 kg / h of oxygen.

[0304] By means of the method of the present invention, all raw materials of TDI-based PU materials, such as amines and polyols, are almost completely recovered, thus completing the value creation cycle.

[0305] The use of renewable energy in water electrolysis further reduces the generation of CO and Cl 2 The CO2 footprint of the produced phosgene results in a sustainable production of TDI or generated PU materials.

[0306] Example 4 Figure 2 )

[0307] In addition to CO 2 Except for the implementation of reduction, this embodiment corresponds to embodiment 3.

[0308] Implement the low temperature CO as described in Example 2 2 Electrolysis as CO 2 30's restoration.

Claims

1. A method for producing phosgene, comprising at least the following steps: The CO2 gas stream (31) is produced by at least the following steps: providing at least one organically modified urethane; hydrolyzing at least one provided organically modified carbamate to form at least an organic amino compound and CO2; separating the CO2 formed to obtain at least one CO2 gas stream; cleaning (4) the CO2 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, preferably by at least one cleaning method selected from condensation, adsorption, catalytic gas cleaning or gas scrubbing, to obtain cleaned carbon dioxide (31a); Reducing (6) CO2 in at least one optionally cleaned CO2 gas stream (31, 31a) produced to carbon monoxide (21a); Phosgene (20) is synthesized (1) from at least carbon monoxide (21a) and chlorine (22) obtained by the reduction.

2. The method according to claim 1, characterized in that The provided organically modified urethane is at least one direct process product of chemical decomposition of a polyurethane material, comprising at least the following method steps: Provide polyurethane materials; The provided polyurethane material is reacted with at least one chemical decomposition agent 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 organic modified carbamate.

3. The method according to any one of claims 1 or 2, characterized in that The CO2 gas stream (31) is produced by chemical decomposition of the polyurethane material, which comprises at least the following steps: Provide polyurethane materials; reacting the provided polyurethane material with at least one chemical decomposition agent 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 organic modified carbamate; hydrolyzing the previously formed organically modified carbamate to form at least an organic amino compound and CO2; The CO 2 formed is separated off to obtain at least one CO 2 gas stream.

4. The method according to claim 3, characterized in that The reaction of providing the polyurethane material to form the organically modified urethane and the hydrolysis of the urethane are carried out together in one process step.

5. The method according to any one of claims 2 to 4, characterized in that The temperature of the obtained CO2 gas stream is from 140°C to 220°C, preferably from 170°C to 200°C.

6. The method according to any one of claims 2 to 5, characterized in that The reaction of providing the polyurethane material to generate the organic modified urethane is achieved using at least one catalyst, which is particularly selected from carbonates, bicarbonates, orthophosphates, monohydrogen orthophosphates, metaphosphates, hydroxides, organic amines, organic metal compounds or a mixture of two or more of the above catalysts.

7. The method according to any one of claims 2 to 6, characterized in that The chemical decomposition agent 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 above alcohols.

8. The method according to any one of the preceding claims, characterized in that The CO2 gas stream (31) is cleaned (4) to remove secondary components and, in this case, is conducted through at least a plurality of condensers and cooled, wherein organic and aqueous components present as secondary components in the gas stream are condensed and separated off in liquid form, and at the end of the cleaning (4), the cleaned CO2 gas stream (31a) is fed to a reduction (6) to form carbon monoxide.

9. The method according to any one of the preceding claims, characterized in that A hydrogen gas stream (29a) is provided and converted together with an optionally cleaned CO2 gas stream (31, 31a) by the principle of the reverse water gas shift reaction into a product gas (39) containing carbon monoxide (21) with or without by-products (32).

10. The method according to claim 9, characterized in that The hydrogen gas stream (29a) is provided by performing electrolysis (5) of water (26) to generate hydrogen (29) and oxygen (27).

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

12. The method according to any one of the preceding claims, characterized in that The optionally cleaned CO2 gas stream is introduced into the electrolysis device for reduction (6) and is reduced to carbon monoxide at the electrodes, preferably at the gas diffusion electrodes.

13. A phosgene production device comprising at least one unit for providing a CO2 gas stream which is the direct product of a process comprising at least a step of hydrolyzing at least one organic compound chosen from organically modified carbamates, wherein the unit comprises at least one CO2 outlet for said CO2 gas stream; Optionally at least one unit for cleaning the CO2 gas stream (31) to remove secondary components, comprising at least one unit from the group formed by a condensation unit, an adsorption unit, a gas scrubbing unit or a catalytic gas cleaning unit, wherein the unit for cleaning the CO2 gas stream has at least one inlet for the CO2 gas stream (31) as the CO2 gas stream to be cleaned, which is connected to the CO2 outlet fluid of the unit for providing the CO2 gas stream, and wherein the unit for cleaning the CO2 gas stream has at least one outlet for the cleaned CO2 gas stream; at least one unit for reducing at least one provided, optionally cleaned, CO2 gas stream (31, 31a) to carbon monoxide (21a), comprising at least one inlet for the CO2 gas stream, which is connected to the outlet fluid of at least one unit for providing the CO2 gas stream, optionally via at least one unit for cleaning the CO2 gas stream, and comprises at least one outlet for carbon monoxide; At least one phosgene production unit comprising at least one inlet for chlorine gas, fluidly connected to a source of chlorine gas, and at least one inlet for carbon monoxide, which is fluidly connected to at least one outlet for carbon monoxide in a unit for reducing said CO2 gas stream; At least one outlet for phosgene.

14. The device according to claim 13, characterized in that The unit for providing a CO2 gas stream comprises a unit for hydrolyzing at least one organic compound, comprising At least one hydrolysis device, comprising at least one inlet for a liquid containing water and a chemical decomposition agent, at least one inlet for a polyurethane material and at least one outlet for a CO2 gas stream, wherein the polyurethane material and the liquid can be contacted in a reaction zone of the hydrolysis device, and the formed CO2 gas stream can be led out through the outlet.

15. The device according to claim 14, characterized in that The unit for providing a CO2 gas stream comprises a unit for hydrolyzing at least one organic compound, comprising at least one chemical decomposition device comprising at least one inlet for a liquid containing a chemical decomposition agent, 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 into at least one organic compound selected from the group consisting of organically modified carbamates; At least one hydrolysis device, comprising at least one inlet for a chemical decomposition reagent, at least one inlet for a liquid containing water, an organically modified carbamate, and at least one outlet for a CO2 gas stream, wherein the organically modified carbamate and the liquid containing water can be contacted in a reaction zone of the hydrolysis device, and the formed CO2 gas stream can be led out via the outlet; wherein the inlet for the organically modified carbamate is connected to an outlet fluid for the organically modified carbamate in the chemical decomposition device.

16. The method according to any one of claims 13 to 15, characterized in that The unit for reducing the at least one optionally cleaned CO 2 gas stream ( 31 , 31 a ) provided is an electrolysis unit with gas diffusion electrodes for CO 2 reduction or a reverse water gas shift reactor.

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