Production of specific isocyanates by co-phosgenation

Abstract

The invention relates to a method for producing isocyanates by phosgenation of the corresponding amines, in particular gas phase phosgenation (GPP) or liquid phase phosgenation (FPP), in which an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to provide a reaction mixture, wherein in particular a higher yield and / or good purity (in the form of a reduced content of acidic chlorine compounds (AC value) and / or a reduced content of hydrolyzable chlorine (HC value) is achieved for the corresponding isocyanates obtained in the production process. The invention also relates to products obtainable or obtained by the method according to the invention, preferably products obtainable or obtained directly by the method according to the invention, and to the use of said products and / or isocyanates or isocyanate mixtures obtained or obtainable by the method according to the invention. The invention also relates to a phosgenation plant for carrying out the method according to the invention.

Description

[0001] The present invention relates to a process for producing isocyanates by phosgenation of the corresponding amines, in particular gas phase phosgenation (GPP) or liquid phase phosgenation (FPP), wherein an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to provide a reaction mixture, wherein for the corresponding isocyanates obtained in the production process, in particular a higher yield and / or a good purity (in the form of a reduced content of acidic chlorine compounds (AC value) and / or a reduced content of hydrolyzable chlorine (HC value)) is achieved. The present invention also relates to products obtainable or obtained by the process according to the invention, preferably products directly obtainable or obtained by the process according to the invention, and to the use of said products and / or isocyanates or isocyanate mixtures obtained or obtainable by the process according to the invention. The present invention also relates to a phosgenation plant for carrying out the process according to the invention.

[0002] Isocyanates, in particular diisocyanates, sometimes also low molecular weight triisocyanates, and higher molecular weight polyaddition products with terminal isocyanate groups obtainable from said compounds, are valuable raw materials for the production of polyurethanes. Isocyanates are produced industrially advantageously by phosgenating the amines on which they are based in the condensed phase (liquid phase phosgenation, hereinafter referred to as FPP) or in the gas phase (gas phase phosgenation, hereinafter referred to as GPP). The latter is only possible in the case of amines that can evaporate without decomposition at a selected pressure. In general, it has been found that many isocyanates that cannot be produced by FPP or can only be produced in a low yield or in an unsatisfactory purity can be produced better by GPP. This is especially true for diisocyanates with sensitive functional groups (e.g. ether bridges) in their molecular structure (see EP-A 764633 and the sources cited therein).

[0003] Even though some isocyanates containing ether groups can be produced in good yields and high purity by GPP, this is not the case for all industrially relevant species in this substance class. For example, the acid number or the content of acidic chlorine compounds (hereinafter referred to as: AC, AC value, AC content) and the content of hydrolyzable chlorine (hereinafter referred to as: HC, HC value, HC content) of 1,5-diisocyanato-3-oxapentane (hereinafter referred to as OBDI) are not low enough to allow the diisocyanate to be processed further without problems in typical polyurethane applications (see comparative examples). Other examples are (poly)cyclic ether-group-containing amines with cyclic ether structural units, such as sugar derivatives (isohexoses) of the furan, dihydrofuran, tetrahydrofuran, sorbitol, mannitol and iditoluol series, in which it is unimportant whether the amino group is attached to the (poly)ring directly or via other bridging atoms. For many compounds, it is very difficult or even impossible to separate out HC-containing impurities by distillation, especially for OBDI.

[0004] The object of the present invention is therefore to provide a process for producing isocyanates by phosgenation (gas phase and / or liquid phase phosgenation) of the corresponding amines, and a phosgenation plant for carrying out the process. In particular, a further object of the present invention is to convert an amine "problematic" in terms of phosgenation (hereinafter also referred to as "amine 1" or "first amine") into the corresponding isocyanate (hereinafter also referred to as "isocyanate 1") in an industrially well-implementable manner. In particular, a high yield and / or a good purity should be achieved in such a way that the content of acidic chlorine compounds (AC value) and / or the content of hydrolyzable chlorine (HC value) of the corresponding isocyanate obtained during the production process is reduced.

[0005] This object is achieved by a process for producing isocyanates by phosgenation of the corresponding amines, wherein an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to give a reaction mixture, characterized in that

[0006] ■ the first amine contains at least one ether group; and

[0007] ■ the second amine is selected from the group comprising or consisting of aminoalkanes having 5 to 15 hydrocarbon atoms without ether groups;

[0008] or

[0009] ■ the first amine contains at least one cyclic ether group; and

[0010] ■ The second amine contains at least one open-chain ether group and no cyclic ether groups.

[0011] The present invention also relates to the use of an amine mixture formed from at least one first amine and at least one second amine different from the first amine in a process according to the invention for producing the corresponding isocyanates by phosgenation for reducing the content of acidic chlorine compounds and / or the content of hydrolyzable chlorine in the corresponding isocyanates obtained during the production process.

[0012] The present invention further relates to a product obtainable or obtained by the process of the present invention, preferably directly obtainable or obtained by the process of the present invention.

[0013] The invention further relates to the use of the products of the invention and / or the isocyanates or isocyanate mixtures obtained or obtainable by the process of the invention as components for the production of polyurethanes, in particular polyurethane foams, polyurethane coatings and polyurethane adhesives, pharmaceuticals, in particular active substances, and auxiliaries, in particular auxiliaries, emulsifiers and thickeners for wet strength finishing of paper and other cellulosic products.

[0014] The present invention also relates to a phosgenation plant for carrying out the process according to the invention, which comprises or consists of:

[0015] (a) at least one phosgene plant for the continuous supply of phosgene, optionally in combination with an inert substance,

[0016] (b) optionally, an inert material device for providing an inert material,

[0017] (c) at least one amine plant for continuously providing an amine mixture, optionally in combination with an inert substance, and

[0018] (d) a phosgenation reactor for mixing phosgene with an amine mixture and optionally an inert substance and reacting the amine mixture with phosgene,

[0019] The amine device comprises a first storage container for a first amine and a second storage container for a second amine, a metering unit for variably adjusting the mass ratio of the first amine and the second amine independently of each other, and optionally a mixing unit for mixing the first amine and the second amine to form an amine mixture.

[0020] Surprisingly, it was found that a mixture of an amine 1 ("first amine") and an amine that is not problematic in terms of phosgenation (hereinafter also referred to as "amine 2" or "second amine") can be converted into a mixture of (one or more) isocyanates 1 and (one or more) isocyanates 2 more easily than in the case of phosgenation of amine 1 alone. This method of the invention is also referred to as cophosgenation hereinafter, or CoPg for short. The yield and quality of the isocyanates 2 obtained (in particular the content of acidic chlorine compounds (AC value) and / or the content of hydrolyzable chlorine compounds (HC value)) are at least comparable to those obtained by phosgenation of amine 2 alone. However, it is particularly surprising that the diisocyanates 2 obtainable from amine 2 by the method of the invention sometimes also have a significantly higher purity than in the case of phosgenation alone under otherwise similar conditions. Further details on this are given in the examples. It was also found that amines with open-chain ether groups are relatively less problematic in terms of phosgenation than amines with cyclic ether groups. It has also been found here that in the process according to the invention, amine mixtures formed from amines having at least one cyclic ether group and amines having only open-chain ether groups show the same above-mentioned improvements in yield and quality, in particular in terms of the content of acidic chlorine compounds (AC value) and / or the content of hydrolyzable chlorine compounds (HC value). In the present invention, the content of acidic chlorine compounds and the content of hydrolyzable chlorine are determined in accordance with ISO 15028:2014.

[0021] Although the phosgenation of isomer mixtures, such as the phosgenation of 2,4- and 2,6-diaminotoluene to the industrially established TDI, and the phosgenation of isomer and homologue mixtures of amines from the condensation of aniline-formaldehyde (MDA->MDI), are well-known examples of the phosgenation of mixtures of individual compounds, the rationale for this process is simply that the production of the amines on which it is based results in isomer and / or homologue mixtures, the separation of which into their individual components would appear uneconomical and technically impractical. Instead, the possible approach here is to separate from the isocyanate mixture those substances which are more easily obtained in pure form by crystallization (2,4-TDI, so-called "T100") or distillation (monomeric MDI, such as 4,4'-bis(isocyanatophenyl)methane, 2,4'-bis(isocyanatophenyl)methane and 2,2'-bis(isocyanatophenyl)methane and any mixtures of the three individual compounds, hereinafter referred to as 2-ring MDI)) without a prior corresponding separation of the amine mixture. In the aliphatic series, IPDA and ring-hydrogenated 2-ring MDA (established abbreviations: H12MDA, PACM) are examples of diamines with inevitably occurring mixtures of regio- and / or stereoisomers, which after phosgenation are converted into the diisocyanates IPDI and H2-MDA, respectively. 12 In the latter case, the pure trans-trans-4,4' isomer can also be isolated by crystallization.

[0022] To date, only DE 2249459 has described the use of mixtures of two (or more) chemically completely different amines originating from completely different production processes for phosgenation purposes. In this case, it is essential for the present invention to use aromatic amines 2 (in the sense of the present application) as "base amines" for the production of aliphatic isocyanates from the corresponding amines in order to avoid having to build expensive separate plants for the aliphatic isocyanates that are usually required in much smaller quantities in technology. The solution to the above-mentioned technical problem is neither the subject of DE 2249459 nor can it be solved according to the teaching therein, as can be seen from the HC content of the isocyanates described in the examples of DE 2249459 (0.1% and more). As shown in Example 1 of the present document, the method of DE 2249459 is also not suitable for solving the problems that exist in the production of specific isocyanates in the context of the present application.

[0023] It is also surprising that, in particular taking into account the mean free path lengths between the different molecules in the gas phase on the one hand and the generally high dilution in the liquid phase on the other hand, the CoPg of the first and second amines (amines 1 and 2) has, in addition to the obvious economic advantages discussed in DE 2249459, a certain beneficial effect on the overall operation, since no second plant is required for the production of tonnages of a specific isocyanate, for example lower than the tonnages usually produced with MDI.

[0024] The invention relates to a process for producing isocyanates by phosgenation of the corresponding amines, wherein an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to provide a reaction mixture, characterized in that

[0025] ■ the first amine contains at least one ether group; and

[0026] ■ the second amine is selected from the group comprising or consisting of aminoalkanes having 5 to 15 hydrocarbon atoms without ether groups;

[0027] or

[0028] ■ the first amine contains at least one cyclic ether group; and

[0029] ■ The second amine contains at least one open-chain ether group and no cyclic ether groups.

[0030] The phosgenation is preferably a gas phase phosgenation (GPP) or a liquid phase phosgenation (FPP). In the process according to the invention, the mixing ratio of the first and second amines (amines 1 and 2) can be varied within a wide range (20:1 to 1:20). Preferably, the mixing ratio of the first amine to the second amine is from 1:9 to 9:1, more preferably from 2:8 to 8:2. Although a high proportion of amine 1 in the amine mixture obviously leads to a higher yield of the isocyanate 1 produced therefrom, in order to produce particularly pure isocyanate 1, it may also be preferred to carry out the CoPg with amine 1 mixed with amine 2 in a proportion that is not too high. In the gas phase phosgenation, it is also possible to vary the ratio of amine 1 to amine 2 (first amine to second amine) during the reaction, provided that only amine 2 is metered in during the start-up phase and finally only amine 1 is metered in after a stable operating state ("steady state") has been reached. In this particular embodiment of the process, use is made of the fact that precisely during the start-up of the gas phase phosgenation, critical phases are usually passed which are easier to manage with amine 2 than with amine 1, and that metering only amine 1 during the start-up phase leads to stopping the experiment.

[0031] When selecting the amines 1 and 2, care should be taken to ensure that the resulting isocyanates 1 and 2 can be separated from one another easily, for example by distillation, extraction or crystallization. However, it is also possible to continue to use the mixture of isocyanates 1 and 2, for example as the mixture which occurs in the process according to the invention (usually after separation of coloring and high-boiling impurities by distillation).

[0032] DE 2249459 explicitly excludes this process, since it was found therein to be essential for the invention that the (two) isocyanates should be able to be separated at the end of the process (see DE 2249459, page 4, last paragraph and claims 1 to 3).

[0033] In particular, the first amine containing at least one ether group, the first amine containing at least one cyclic ether group, the second amine containing or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms and / or the second amine containing at least one open-chain ether group and containing no cyclic ether group is a diamine.

[0034] The first amine containing at least one ether group preferably has the general formula X-(-R 1 -NH m ) n The structure of

[0035] -X is H, NH m or C(R 2 ) p ;

[0036] -R 1 is an optionally substituted and / or heteroatom-containing aliphatic, (cyclo)aliphatic or aromatic radical, preferably having up to 10 carbon atoms, wherein R 1 Containing at least one ether group;

[0037] -R 2 is H or an optionally substituted and / or heteroatom-containing aliphatic, (cyclo)aliphatic or aromatic group, which preferably has up to 10 carbon atoms;

[0038] -m is 1 or 2;

[0039] -n is 1, 2, or 3; and

[0040] -p is 1, 2, or 3.

[0041] In a preferred embodiment, the first amine containing at least one ether group is selected from the group consisting of (tetrahydrofuran-2,5-diyl)dimethylamine (TEFUDA), 3,6-diaminohexahydrofuro[3,2-b]furan (e.g., IDDA and / or ISODA), 3,6-bis(aminomethyl)hexahydrofuro[3,2-b]furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5, dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine; di(aminoethyl)ethers, in particular 2,2'-oxybis(ethyl-1-amine), 1,1'-oxybis(propan-2-amine), 2-(2-aminoethoxy)propan-1-amine, 2,2'-oxybis(propan-1-amine) and 2-(2-aminopropoxy)propan-1-amine; di(aminopropyl)ethers, or mixtures thereof. The first amine containing at least one cyclic ether group is preferably selected from (tetrahydrofuran-2,5-diyl)dimethylamine (TEFUDA), 3,6-diaminohexahydrofuro[3,2-b]furan (e.g. IDDA and / or ISODA), 3,6-bis(aminomethyl)hexahydrofuro[3,2-b]furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine or mixtures thereof.

[0042] Further preferably, the second amine comprising or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms is selected from 1,5-diaminopentane; 1,6-diaminohexane; 1-amino-3,5,5-trimethyl-5-aminomethylcyclohexane; amino-[(aminocyclohexyl)methyl]cyclohexane, in particular 4,4'-methylenebis(cyclohexane-1-amine), 2-((4-aminocyclohexyl)methyl)cyclohexane-1-amine and 2,2'-methylenebis( cyclohexane-1-amine); 1,3-bis(aminomethyl)cyclohexane; 1,4-bis(aminomethyl)cyclohexane; diaminocyclohexanes, especially cyclohexane-1,2-diamine, cyclohexane-1,3-diamine and cyclohexane-1,4-diamine; methyldiaminocyclohexanes, especially 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine; 4,4'-methylenebis(2-methylcyclohexane-1-amine); or mixtures thereof. However, many other amines may also be suitable as "amine 2", which can be easily determined by simple preliminary experiments.

[0043] The second amine containing at least one open-chain ether group and no cyclic ether group is preferably selected from the group consisting of: di(aminoethyl) ether, di(aminopropyl) ether, 1,8-diamino-1,5,8-trimethyl-3,6-dioxaoctane, 1,11-diamino-1,5,8,11-tetramethylundecane, 1,8-diamino-3,6-dioxaoctane, 1,10-diamino-4,7-dioxadecane, 1,12-diamino-4,9-dioxadodecane, 1,14-diamino-3,10-dioxatetradecane, 1,13-diamino-4,7,10- trioxatridecane, 1,7-diamino-2,6-dioxa-4-aminomethoxyheptane, 1-amino-2-oxa-3,3-bis(aminomethoxy)hexane, 1,9-diamino-3,7-dioxa-5-(1-amino-2-ethoxy)-nonane, 1-amino-3-oxa-4,4-bis(1-amino-2-ethoxy)heptane, 1,11-diamino-4,8-dioxa-6-(1-amino-5-oxabutyl)undecane, 1-amino-4-oxa-5,5-bis(1-amino-5-oxabutyl)octane or mixtures thereof.

[0044] In a particular embodiment of the gas phase phosgenation, the limiting factor for the use of monoamines and polyamines containing ether groups in the CoPg of the invention is neither the number of (primary) amino groups nor the number of ether bonds, but only the volatility under the applied pressure. Therefore, it may be advantageous for compounds with particularly high boiling points to introduce them into the gas phase phosgenation in the form of azeotropes with other substances or to use a carrier gas to feed the amine mixture into the reaction space. In this case, amine 2 can have a promoting effect.

[0045] Furthermore, it is preferred that

[0046] ■ The mass proportion of the first amine is 5.0 to 95.0% by weight, preferably 10.0 to 80.0% by weight, and

[0047] ■ The mass proportion of the second amine is 95.0 to 5.0% by weight, preferably 90.0 to 20.0% by weight, more preferably 80.0 to 20.0% by weight,

[0048] Based on the total weight of the amine mixture.

[0049] The molar ratio of phosgene to the amino groups of the amines in the amine mixture is preferably ≧1:1 to ≦5:1, preferably >1:1 to ≦3:1, more preferably >1:1 to ≦2:1.

[0050] Preferably, an inert substance is additionally used in the reaction, wherein the inert substance is selected from:

[0051] ■Inert gases, especially nitrogen, argon or mixtures thereof;

[0052] ■ an inert solvent, in particular an aromatic hydrocarbon, preferably chlorobenzene, o-dichlorobenzene, toluene, xylene or a mixture thereof;

[0053] ■ Or a mixture of the above inert gases and inert solvents.

[0054] Preferably, the temperature

[0055] ■ On the one hand, in condensed phase reactions, from -40°C to the boiling point of the solvent or the lowest boiling starting material used at the pressure set in the reaction, and

[0056] ■ In gas phase phosgenation, the boiling point of the reactants having the highest boiling point T1 at the plant pressure is in the range of up to 600°C, preferably T1 to 550°C, more preferably T1 to 500°C.

[0057] It is also preferred that the isocyanate corresponding to the first amine and / or the isocyanate corresponding to the second amine is separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained individually or as an isocyanate mixture. It is further preferred that the isocyanate corresponding to the first amine and the isocyanate corresponding to the second amine are separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained individually or as an isocyanate mixture. The content of acidic chlorine compounds (also referred to as AC value, AC content or acidity) in the separated one or more isocyanates or isocyanate mixtures is determined according to ISO 15028:2014 standard to be 1 to 100 ppm, preferably 2 to 80 ppm, more preferably 5 to 50 ppm. The content of hydrolyzable chlorine in the separated one or more isocyanates or isocyanate mixtures (also referred to as HC value or HC content) is determined according to ISO 15028:2014 standard and is 1 to 500 ppm, preferably 5 to 100 ppm.

[0058] In a preferred embodiment, the invention relates to a process for producing isocyanates by phosgenation of the corresponding amines, wherein an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to provide a reaction mixture, characterized in that

[0059] ■ the first amine contains at least one ether group; and

[0060] ■ the second amine is selected from the group comprising or consisting of aminoalkanes having 5 to 15 hydrocarbon atoms without ether groups;

[0061] or

[0062] ■ the first amine contains at least one cyclic ether group; and

[0063] ■The second amine contains at least one open-chain ether group and no cyclic ether group,

[0064] wherein the first amine containing at least one ether group is selected from: (tetrahydrofuran-2,5-diyl)dimethylamine, 3,6-diaminohexahydrofurano[3,2-b]furan, 3,6-bis(aminomethyl)hexahydrofurano[3,2-b]furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine; di(aminoethyl)ethers, in particular 2,2'-oxybis(ethyl-1-amine), 1,1'-oxybis(propan-2-amine), 2-(2-aminoethoxy)propan- 1-amine, 2,2'-oxybis(propan-1-amine) and 2-(2-aminopropoxy)propan-1-amine; di(aminopropyl)ether or a mixture thereof and / or the first amine containing at least one cyclic ether group is selected from: (tetrahydrofuran-2,5-diyl)dimethylamine, 3,6-diaminohexahydrofurano[3,2-b]furan, 3,6-bis(aminomethyl)hexahydrofurano[3,2-b ] furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine or a mixture thereof,

[0065] The second amine comprising or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms is selected from the group consisting of: 1,5-diaminopentane; 1,6-diaminohexane; 1-amino-3,5,5-trimethyl-5-aminomethylcyclohexane; amino-[(aminocyclohexyl)methyl]cyclohexane, in particular 4,4'-methylenebis(cyclohexane-1-amine), 2-((4-aminocyclohexyl)methyl)cyclohexane-1-amine and 2,2'-methylenebis(cyclohexane-1-amine. cyclohexane-1-amine); 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane; diaminocyclohexanes, especially cyclohexane-1,2-diamine, cyclohexane-1,3-diamine and cyclohexane-1,4-diamine; methyldiaminocyclohexanes, especially 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine, 4,4'-methylenebis(2-methylcyclohexane-1-amine); or mixtures thereof,

[0066] The second amine containing at least one open-chain ether group and no cyclic ether group is selected from the group consisting of di(aminoethyl)ether, di(aminopropyl)ether, 1,8-diamino-1,5,8-trimethyl-3,6-dioxaoctane, 1,11-diamino-1,5,8,11-tetramethylundecane, 1,8-diamino-3,6-dioxaoctane, 1,10-diamino-4,7-dioxadecane, 1,12-diamino-4,9-dioxadodecane, 1,14-diamino-3,10-dioxatetradecane, 1,13-diamino-4,7,10 -trioxatridecane, 1,7-diamino-2,6-dioxa-4-aminomethoxyheptane, 1-amino-2-oxa-3,3-bis(aminomethoxy)hexane, 1,9-diamino-3,7-dioxa-5-(1-amino-2-ethoxy)-nonane, 1-amino-3-oxa-4,4-bis(1-amino-2-ethoxy)heptane, 1,11-diamino-4,8-dioxa-6-(1-amino-5-oxabutyl)undecane, 1-amino-4-oxa-5,5-bis(1-amino-5-oxabutyl)octane or a mixture thereof. This embodiment can be combined with other embodiments at will, as long as there is no contrary situation in the context.

[0067] The present invention also relates to the use of an amine mixture formed from at least one first amine and at least one second amine different from the first amine in a process for producing the corresponding isocyanates by phosgenation according to any one of claims 1 to 13 for reducing the content of acidic chlorine compounds and / or the content of hydrolyzable chlorine in the corresponding isocyanates obtained during the production process.

[0068] A further subject of the present invention is also the product obtainable or obtained by the process according to the invention, preferably directly obtainable or obtained by the process according to the invention.

[0069] The present invention also provides for the use of the products of the invention and / or the isocyanates or isocyanate mixtures obtained or obtainable by the process of the invention as components for the production of polyurethanes, in particular polyurethane foams, polyurethane coatings and polyurethane adhesives, pharmaceuticals, in particular active substances, and auxiliaries, in particular auxiliaries, emulsifiers and thickeners for wet strength finishing of paper and other cellulosic products.

[0070] The main feature of the GPP process of the present invention is the use of methods known per se in the prior art, for example according to the teachings of EP0570799 or EP 0676392 and the method variants cited therein. For this purpose, the reaction partners are introduced into a suitable reactor close to or above the boiling point of the starting amine (mixture), mixed and reacted with each other. Depending on the selected pressure, the temperature is 100 to 600° C., preferably 150 to 500° C. The method is carried out in a pressure range of 10 mbar to 5 bar, preferably 200 mbar to 3 bar. The reaction components in the gas phase phosgenation can be fed with or without additives (such as carrier gases) that are inert to the phosgenation reaction. Suitable carrier gases include nitrogen, argon or other inert gases, as well as vapors of technically available solvents, such as vapors of chlorobenzene, dichlorobenzene, xylene, chloronaphthalene, decalin, etc.

[0071] The isocyanate mixture of the invention is then obtained by cooling the gas stream to a temperature above the decomposition temperature of the corresponding carbamoyl chloride intermediate. In a preferred embodiment, the isocyanate corresponding to the first amine and / or the isocyanate corresponding to the second amine are then separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained individually or as an isocyanate mixture. Particularly preferably, the isocyanate corresponding to the first amine and the isocyanate corresponding to the second amine are separated from the reaction mixture. It is also preferred that the separation by distillation is optionally followed by recrystallization.

[0072] The products of the process according to the invention are valuable raw materials for the production of polyurethanes, adhesives, coatings, oligomeric isocyanate-modified products (e.g. polyisocyanates containing uretdione, isocyanurate, carbodiimide, biuret, urethane and allophanate), auxiliaries (e.g. auxiliaries for wet strength finishing of paper and other cellulosic products, in particular as emulsifiers, thickeners, etc.), as raw materials for the production and / or formulation of active substances, pharmaceuticals, etc.

[0073] Finally, the present invention also relates to a phosgenation plant for carrying out the process according to the invention, which comprises or consists of:

[0074] (a) at least one phosgene plant for the continuous supply of phosgene, optionally in combination with an inert substance,

[0075] (b) optionally, an inert material device for providing an inert material,

[0076] (c) at least one amine plant for continuously providing an amine mixture, optionally in combination with an inert substance,

[0077] (d) a phosgenation reactor for mixing phosgene with an amine mixture and optionally an inert substance and reacting the amine mixture with phosgene,

[0078] The amine device comprises a first storage container for a first amine and a second storage container for a second amine, a metering unit for variably adjusting the mass ratio of the first amine and the second amine independently of each other, and optionally a mixing unit for mixing the first amine and the second amine to form an amine mixture.

[0079] The phosgene stream, the optional inert stream, the amine stream and the phosgenation reactor may, independently of one another, comprise further devices which can be used for operating the phosgenation plant, for example storage containers for the starting materials, heat exchangers for temperature control or, optionally, evaporation of the starting materials, units for purifying the reaction mixture after the reaction of amine with phosgene is complete.

[0080] The metering unit can be, for example, a metering pump or a control valve. The optional mixing unit can be, for example, a T-piece in a pipeline, a mixing chamber, a static mixer or a pump (especially a mixing pump) or a stirred vessel. However, the amine streams from the metering unit can also be mixed in an evaporator. In particular, an evaporator is used in the case of liquid amines.

[0081] The amine flow device preferably comprises at least one flange connection in at least one amine-conducting line, which is used to accommodate an insert disk. This makes it possible to reliably block the amine flow through the corresponding line or to reliably shut off the corresponding amine line by the insert disk.

[0082] The phosgene stream device, the optional inert material stream device and the amine stream device are each connected to the phosgenation reactor by at least one feed pipe. The connection of the feed pipe to the phosgenation reactor can be realized, for example, by simple pipelines, flange connections, smooth jet nozzles, annular gap nozzles or mixing elements. The annular gap nozzle can be equipped with two or more channels for amine stream and phosgene stream or inert gas stream, preferably two coaxially arranged channels, wherein the amine stream and the phosgene stream are not met until the phosgenation reactor. Or, especially in industrial-scale applications, amine is added to the phosgenation reactor via an inlet pipe having a central nozzle at its end and held in place by a cover and an optional fixture / rectifier, to form an annular space around the inlet pipe in the reactor, wherein phosgene enters the annular space via a separate inlet and arrives at the phosgenation reactor via a rectifier from here (also referring to EP1362847A2). The phosgenation reactor has a mixing zone and a reaction zone, in which the stream first meets in the mixing zone, and in the reaction zone, the stream is further converted. The mixing zone and the reaction zone are preferably in a device. Furthermore, it is preferred that the phosgenation reactor is essentially vertical and that this is preferably connected at the upper end to a phosgene flow device and an amine flow device.

[0083] The phosgenation plant also preferably comprises at least one quench for cooling and at least partially condensing the reaction mixture, which is connected to the phosgenation reactor, preferably at the lower end, wherein the quench is designed in particular for introducing chlorobenzene, o-dichlorobenzene and / or at least one isocyanate produced in the phosgenation plant. In particular, the quench is assigned a collecting container, wherein the collecting container is preferably integrated into the quench or is separately connected to the quench.

[0084] Preferably, the amine plant, the optional separate inert substance plant and / or the phosgene plant comprise a heat exchanger for heating the amine mixture, phosgene and / or the optional inert substance.

[0085] Implementation plan:

[0086] The present invention particularly relates to the following embodiments:

[0087] In a first embodiment, the invention relates to a process for producing isocyanates by phosgenation of the corresponding amines, wherein an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to provide a reaction mixture, characterized in that

[0088] ■ the first amine contains at least one ether group; and

[0089] ■ the second amine is selected from the group comprising or consisting of aminoalkanes having 5 to 15 hydrocarbon atoms without ether groups;

[0090] or

[0091] ■ the first amine contains at least one cyclic ether group; and

[0092] ■ The second amine contains at least one open-chain ether group and no cyclic ether groups.

[0093] In a second embodiment, the invention relates to a process according to embodiment 1, characterized in that the first amine containing at least one ether group has the general formula X-(-R 1 -NH m ) n The structure of

[0094] -X is H, NH m or C(R 2 ) p ;

[0095] -R 1 is an optionally substituted and / or heteroatom-containing aliphatic, (cyclo)aliphatic or aromatic radical, preferably having up to 10 carbon atoms, wherein R 1 Containing at least one ether group;

[0096] -R 2 is H or an optionally substituted and / or heteroatom-containing aliphatic, (cyclo)aliphatic or aromatic group, which preferably has up to 10 carbon atoms;

[0097] -m is 1 or 2;

[0098] -n is 1, 2, or 3; and

[0099] -p is 1, 2, or 3.

[0100] In a third embodiment, the invention relates to a method according to embodiment 1 or 2, characterized in that the first amine containing at least one ether group, the first amine containing at least one cyclic ether group, the second amine containing or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms and / or the second amine containing at least one open-chain ether group and containing no cyclic ether groups is a diamine.

[0101] In a fourth embodiment, the invention relates to a method according to any of the preceding embodiments, characterized in that the first amine containing at least one ether group is selected from the group consisting of (tetrahydrofuran-2,5-diyl)dimethylamine (TEFUDA), 3,6-diaminohexahydrofuro[3,2-b]furan (e.g. IDDA and / or ISODA), 3,6-bis(aminomethyl)hexahydrofuro[3,2-b]furan, furan-2,5-diyl dimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine; bis(aminoethyl)ethers, especially 2,2'-oxybis(ethyl-1-amine), 1,1'-oxybis bis(aminopropyl)ether or a mixture thereof and / or the first amine containing at least one cyclic ether group is selected from (tetrahydrofuran-2,5-diyl)dimethylamine, 3,6-diaminohexahydrofuro[3,2-b]furan (e.g., IDDA and / or ISODA), 3,6- Bis(aminomethyl)hexahydrofuro[3,2-b]furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine or a mixture thereof.

[0102] In a fifth embodiment, the invention relates to a method according to any of the preceding embodiments, characterized in that the second amine comprising or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms is selected from: 1,5-diaminopentane; 1,6-diaminohexane; 1-amino-3,5,5-trimethyl-5-aminomethylcyclohexane; amino-[(aminocyclohexyl)methyl]cyclohexane, in particular 4,4'-methylenebis(cyclohexane-1-amine), 2-((4-aminocyclohexyl)methyl)cyclohexane -1-amine and 2,2'-methylenebis(cyclohexane-1-amine); 1,3-bis(aminomethyl)cyclohexane; 1,4-bis(aminomethyl)cyclohexane; diaminocyclohexanes, especially cyclohexane-1,2-diamine, cyclohexane-1,3-diamine and cyclohexane-1,4-diamine; methyldiaminocyclohexanes, especially 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine; 4,4'-methylenebis(2-methylcyclohexane-1-amine); or mixtures thereof.

[0103] In a sixth embodiment, the invention relates to a method according to any of the preceding embodiments, characterized in that the second amine containing at least one open-chain ether group and no cyclic ether groups is selected from the group consisting of: di(aminoethyl) ether, di(aminopropyl) ether, 1,8-diamino-1,5,8-trimethyl-3,6-dioxaoctane, 1,11-diamino-1,5,8,11-tetramethylundecane, 1,8-diamino-3,6-dioxaoctane, 1,10-diamino-4,7-dioxadecane, 1,12-diamino-4,9-dioxadodecane, 1,14-diamino-3,10-dioxatetradecane , 1,13-diamino-4,7,10-trioxatridecane, 1,7-diamino-2,6-dioxa-4-aminomethoxyheptane, 1-amino-2-oxa-3,3-bis(aminomethoxy)hexane, 1,9-diamino-3,7-dioxa-5-(1-amino-2-ethoxy)-nonane, 1-amino-3-oxa-4,4-bis(1-amino-2-ethoxy)heptane, 1,11-diamino-4,8-dioxa-6-(1-amino-5-oxabutyl)undecane, 1-amino-4-oxa-5,5-bis(1-amino-5-oxabutyl)octane or a mixture thereof.

[0104] In a seventh embodiment, the invention relates to a method according to any one of the preceding embodiments, characterized in that

[0105] ■ The mass proportion of the first amine is 5.0 to 95.0% by weight, preferably 10.0 to 80.0% by weight, and

[0106] ■ The mass proportion of the second amine is 95.0 to 5.0% by weight, preferably 90.0 to 20.0% by weight, more preferably 80.0 to 20.0% by weight,

[0107] Based on the total weight of the amine mixture.

[0108] In an eighth embodiment, the invention relates to a process according to any of the preceding embodiments, characterized in that the molar ratio of phosgene to the amino groups of the amines in the amine mixture is ≥1:1 ​​to ≤5:1, preferably >1:1 to ≤3:1.

[0109] In a ninth embodiment, the invention relates to a method according to any one of the preceding embodiments, characterized in that an inert substance is used in the reaction, wherein the inert substance is selected from:

[0110] ■Inert gases, especially nitrogen, argon or mixtures thereof;

[0111] ■ an inert solvent, in particular an aromatic hydrocarbon, preferably chlorobenzene, o-dichlorobenzene, toluene, xylene or a mixture thereof;

[0112] ■ Or a mixture of the above inert gases and inert solvents.

[0113] In a tenth embodiment, the invention relates to a method according to any one of the preceding embodiments, characterized in that the temperature

[0114] ■ On the one hand, in condensed phase reactions, from -40°C to the boiling point of the solvent or the lowest boiling starting material used at the pressure set in the reaction, and

[0115] ■ In gas phase phosgenation, the boiling point of the reactants having the highest boiling point T1 at the plant pressure is in the range of up to 600°C, preferably T1 to 550°C, more preferably T1 to 500°C.

[0116] In an eleventh embodiment, the invention relates to a process according to any of the preceding embodiments, characterized in that the isocyanate corresponding to the first amine and / or the isocyanate corresponding to the second amine is separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin-film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained individually or as an isocyanate mixture.

[0117] In a twelfth embodiment, the invention relates to a process according to any one of embodiments 1 to 10, characterized in that the isocyanate corresponding to the first amine and / or the isocyanate corresponding to the second amine is separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin-film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained as a mixture of isocyanates.

[0118] In a thirteenth embodiment, the present invention relates to a method according to embodiment 11 or 12, characterized in that the content of acidic chlorine compounds in the separated one or more isocyanates or isocyanate mixtures is 1 to 100 ppm, preferably 2 to 80 ppm, more preferably 5 to 50 ppm, determined according to ISO 15028:2014 standard.

[0119] In a fourteenth embodiment, the present invention relates to a method according to any one of embodiments 11 to 13, characterized in that the content of hydrolyzable chlorine in the separated one or more isocyanates or isocyanate mixtures is determined according to ISO 15028:2014 standard and is 1 to 500 ppm, preferably 5 to 100 ppm.

[0120] In a fifteenth embodiment, the present invention relates to the use of an amine mixture formed from at least one first amine and at least one second amine different from the first amine in a process for producing the corresponding isocyanates by phosgenation according to any one of embodiments 1 to 14 for reducing the content of acidic chlorine compounds and / or the content of hydrolyzable chlorine of the corresponding isocyanates obtained during the production process.

[0121] In a sixteenth embodiment, the present invention relates to a product obtainable or obtained by a process according to any one of embodiments 1 to 13, preferably according to any one of embodiments 10 or 12 to 14, preferably directly obtainable or obtained by any one of embodiments 1 to 13, preferably according to any one of embodiments 10 or 12 to 14.

[0122] In a seventeenth embodiment, the present invention relates to the use of the product according to embodiment 16 and / or the isocyanate or isocyanate mixture obtained or obtainable by the process according to any one of embodiments 11 to 14, preferably according to any one of embodiments 10 or 12 to 14, as a component for the production of polyurethanes (especially polyurethane foams, polyurethane coatings and polyurethane adhesives), pharmaceuticals (especially active substances) and auxiliaries (especially auxiliaries, emulsifiers and thickeners for wet strength finishing of paper and other cellulosic products).

[0123] In an eighteenth embodiment, the present invention relates to a phosgenation plant for carrying out the method according to embodiments 1 to 14, comprising or consisting of:

[0124] (a) at least one phosgene plant for the continuous supply of phosgene, optionally in combination with an inert substance,

[0125] (b) optionally, an inert material device for providing an inert material,

[0126] (c) at least one amine plant for continuously providing an amine mixture, optionally in combination with an inert substance, and

[0127] (d) a phosgenation reactor for mixing phosgene with an amine mixture and optionally an inert substance and reacting the amine mixture with phosgene,

[0128] The amine device comprises a first storage container for a first amine and a second storage container for a second amine, a metering unit for variably adjusting the mass ratio of the first amine and the second amine independently of each other, and optionally a mixing unit for mixing the first amine and the second amine to form an amine mixture.

[0129] In a nineteenth embodiment, the invention relates to a device according to embodiment 18, characterized in that the amine device, the optional separate inert substance device and / or the phosgene device comprise a heat exchanger for heating the amine mixture, phosgene and / or the optional inert substance. Example:

[0130] The examples described below shall describe the process and some of the process products according to the invention in more detail, without limiting the invention; unless otherwise stated, all percentage data are based on mass.

[0131] 1 The mole % data were determined by H-NMR spectroscopy. The measurements were performed on a Bruker DPX400 or DRX 700 instrument by drying about 5% ( 1 HNMR) or about 50% ( 13 C NMR) samples were measured at 400 or 700 MHz ( 1 HNMR) or 100 or 176 MHz ( 13 The ppm scale was based on tetramethylsilane in the solvent. 1 H-NMR chemical shift is 0 ppm. Alternatively, C6D5H in the NMR solvent is used as a reference signal (7.15 ppm, 1 H-NMR), or the solvent signal itself ( 13 The middle signal of the 1:1:1 triplet state at 128.0 ppm in C NMR was used as a reference signal. 15 N-NMR chemical shift is indirectly measured by 1 H- 15 The N-HMBC measurement was determined where the external reference was (liquid) ammonia (0 ppm).

[0132] The dynamic viscosity was determined at 23° C. using an MCR 501 rheometer (from Anton Paar) in accordance with DIN EN ISO 3219:1994-10. The measurements at different shear rates ensured that Newtonian flow behavior could be assumed. The data on shear rate can therefore be omitted.

[0133] The NCO content is determined by titration in accordance with DIN EN ISO 10283:2007-11.

[0134] The residual monomer content is determined in accordance with DIN EN ISO 10283:2007-11 by gas chromatography with an internal standard.

[0135] Determination of the content of acidic chlorine compounds and hydrolyzable chlorine according to ISO 15028:2014.

[0136] GC-MS was performed using an Agilent GC6890 equipped with a MN 725825.30 Optima-5MS Accent capillary column (30 m, inner diameter 0.25 mm, film thickness 0.5 μm) and a 5973 mass spectrometer as a detector, with helium as the carrier gas (flow rate 2 ml / min). The column temperature was initially 60° C. (2 min) and then gradually increased to 360° C. at a rate of 8 K / min. GC-MS detection was performed using electron impact ionization with an ionization energy of 70 eV. The injector temperature was selected to be 250° C.

[0137] Size Exclusion Chromatography (SEC) was performed according to DIN 55672-1:2016-03 with tetrahydrofuran as eluent.

[0138] X-ray crystallographic structure analysis was performed at 106-107 K using a CCD area detector (Ruby model), a Cu Kα The source and Osmic mirror were used as monochromators in Oxford Diffraction Xcalibur. Data acquisition and processing were performed using CrysAlis program version 1.171.38.43 (Rigaku 2015). Structural elucidation was performed using SHELXTL version 6.14 (BrukerAXS, 2003).

[0139] The Hazen color value is measured spectrophotometrically according to DIN EN ISO 6271-2:2005-03 using a Lico 400 spectrophotometer from Lange, Germany.

[0140] All reactions were carried out in glassware previously dried in vacuum at 150-200°C under nitrogen atmosphere.

[0141] The diisocyanates used were products of the company Covestro. All other commercial chemicals were from the company Aldrich, D-82018 Taufkirchen.

[0142] 1,5-Diamino-3-oxapentane (OBDA) was from BASF SE. TEFUDA, (3R,3aR,6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diamine (ISODA) and (3S,3aR,6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diamine (IDDA) were prepared from the corresponding hydroxy compounds according to literature methods: S. Thiyagarajan, L. Gootjes, W. Vogelzang, J. van Haveren, M. Lutz, DS van Es Chem Sus Chem 2011, 4, 1823-1829).

[0143] General operating procedures

[0144] A Liquid Phase Phosgenation (FPP)

[0145] In a 4-necked flask cooled to -5°C with a mechanical stirrer, a dropping funnel, an internal thermometer and an inlet tube, 500 ml of monochlorobenzene (MCB) are initially charged, two times the molar amount of phosgene based on the diamine (mixture) to be reacted is added by condensation, and the solution of the respective amine (mixture) is slowly added dropwise to MCB while further cooling to -10 to a maximum of 0°C. After all the amines (mixture) have been added, 100 ml of MCB are charged to the dropping funnel and added dropwise to the reaction mixture as well. While introducing phosgene (about 120 g / h) through the inlet tube, the temperature is then gradually increased until MCB reflux occurs. After reaching the boiling temperature, stirring is continued under reflux while further passing phosgene (about 120 g / h) until a clear solution is formed, but for at least 5 hours. In order to remove phosgene, stirring is continued under reflux, but dry nitrogen is passed through the inlet tube instead of phosgene until the absence of phosgene is ensured by means of phosgene test paper. Further post-treatment is described in the individual examples.

[0146] B Gas Phase Phosgenation (GPP)

[0147] In a glass apparatus with a heatable mixing tube with a diameter of 2.5 mm and a length of 17.5 mm, a downstream condensation stage and a subsequent phosgene adsorption tower equipped with activated carbon, phosgene preheated in an upstream heat exchanger is continuously introduced via a nozzle extending into the mixing tube. The same preheated amine mixture is introduced into the reaction space at the same time through the annular gap between the nozzle and the mixing tube at a metering rate optimized according to the amine (mixture), and the amine mixture is optionally diluted with the same preheated dry nitrogen as a diluent. A specific pressure is maintained in the mixing tube by applying a negative pressure at the end of the condensation stage. The hot reaction mixture leaving the reaction space in gaseous form is introduced into the condensation stage by boiling 1,2-dichlorobenzene under reflux. This leads to the selective condensation of the diisocyanate that has been formed. The gas mixture consisting essentially of nitrogen, HCl and excess phosgene in the washing stage is then dephosgeneated in the adsorption tower, and the condensate is dephosgeneated with residual dissolved phosgene as described in A. Further post-treatment is described in each embodiment.

[0148] Example 1 (comparative experiment)

[0149] a) Liquid phase phosgenation of OBDA,

[0150] b) cophosgenation of OBDA with MDA according to DE 2249459, and

[0151] c) Cophosgenation of IDDA with MDA according to DE 2249459.

[0152] a)

[0153] 20.83 g (0.2 mol) of OBDA were dissolved in about 400 ml of MCB and phosgenated according to general procedure A. The reaction mixture thus obtained was investigated by GC / GC-MS. In addition to the solvent, 3 main components were detected in a ratio of 3:1:47 to one another: 2-chloroethyl isocyanate, 2-(2-chloroethoxy)ethyl isocyanate and OBDI. After separation of low boilers (monochlorobenzene and 2-chloroethyl isocyanate) under reduced pressure by means of a 40 cm long packed column (inner diameter about 25 mm, packing: #1 Interpack), the remaining virtually solvent-free distillation residue was then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave 10.5 g of a dark brown, highly viscous distillation residue (NCO content 10.8%) and 15.2 g of a light-colored distillate (NCO content 53.0%, AC / HC content 220 / 560 ppm), which, according to NMR and GC-MS determination, consisted of about 98% OBDI and about 2% 2-(2-chloroethoxy)ethyl isocyanate (OBDI yield based on the amine used was about 50%). After a few days, the previously almost colorless liquid changed color noticeably. The product was not suitable for further problem-free use in typical polyurethane applications.

[0154] b)

[0155] A mixture of 4.17 g (0.04 mol) of OBDA and 31.78 g of MDA was dissolved in about 400 ml of monochlorobenzene and phosgenated according to general procedure A. The reaction mixture thus obtained was investigated by GC / GC-MS. In addition to the solvent and the aromatic isocyanate, three main components were detected in a ratio of 8.5:1:139: 2-chloroethyl isocyanate, 2-(2-chloroethoxy)ethyl isocyanate and OBDI. After separation of the low boilers (monochlorobenzene and 2-chloroethyl isocyanate) under reduced pressure by means of a 40 cm long packed column (inner diameter about 25 mm, packing: #1 Interpack), the remaining, essentially solvent-free distillation residue was then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave 29.5 g of a dark brown, highly viscous distillation residue (NCO content 26.8%, which was not further analyzed, mainly polymeric MDI) and 12.7 g of a pale yellow distillate (NCO content 40.0%), which according to NMR and GC-MS consisted of about 31.3% OBDI, about 0.2% 2-(2-chloroethoxy)ethyl isocyanate and about 68.1% 2-cyclic MDI (3 different isomers, mainly the 4,4'-isomer) and other unidentified impurities (yield of OBDI based on the OBDA used, about 64%). The high content of cleavage products (2-chloroethyl isocyanate, 2-(2-chloroethoxy)ethyl isocyanate) and the low yield of OBDI indicated that the procedure according to DE 2249459 would not succeed when using the first amine (amine 1).

[0156] c)

[0157] A mixture of 5.8 g (0.04 mol) of IDDA and 32.0 g of MDA was dissolved in about 1000 ml of monochlorobenzene and phosgenated according to general procedure A. The reaction mixture thus obtained was substantially freed from the solvent on a rotary evaporator under reduced pressure and then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave 20.8 g of a dark brown, highly viscous distillation residue (NCO content 28.0%, consisting predominantly of polymeric MDI according to GPC and NMR) and 27.6 g of a pale yellow distillate (which, according to NMR and GC-MS, consisted of about 25% IDDI and about 75% 2-ring MDI (3 different isomers, predominantly the 4,4′-isomer) as well as other unidentified impurities. Separation of this mixture by distillation failed. Even after repeated recrystallization from hot isooctane, aromatic diisocyanates still remained in the IDDI. When using the first amine (amine 1), the procedure according to DE 2249459 was not successful.

[0158] Example 2 (Comparative Experiment) Preparation of IDDI from IDDA by FPP without using a second amine

[0159] 28.5 g (0.2 mol) of IDDA were phosgenated according to general procedure A. The reaction mixture thus obtained was substantially freed of the solvent on a rotary evaporator under reduced pressure and then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave 12.2 g of a dark brown, highly viscous distillation residue and 21.3 g of a light-colored distillate which crystallized after a period of time and which, according to a combination of analytical methods (NMR, GC-MS), consisted of about 98% IDDI (yield 53% based on the amine used, AC / HC: 616 / 758 ppm). After storage for several days at room temperature with exclusion of air, the previously almost colorless solid changed color noticeably. The product is not suitable for further problem-free use in typical polyurethane applications.

[0160] Example 3 (according to the invention): CoPg-FPP of IDDA (first amine) and PACM 20 (second amine)

[0161] 33.7 g (0.16 mol) of PACM 20 and 5.8 g (0.04 mol) of IDDA were phosgenated according to general procedure A. The reaction mixture thus obtained was substantially freed from the solvent on a rotary evaporator under reduced pressure and then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave only 6.2 g of a dark brown, highly viscous distillation residue and 45.7 g of a light-colored distillate, which after a period of time deposited a certain proportion of crystalline material, which, according to a combination of analytical methods (NMR, GC-MS), consisted of about 13% of IDDI and 84% of H 12 -MDI composition (yields of 78% and 91%, based on the amine used). Subsequent fractional distillation gave 5.6 g of a colorless, rapidly crystallizing distillate (boiling point 83° C. at 0.1 mbar, melting point 42° C.), which, even after storage for several weeks at room temperature with exclusion of air, showed no tendency to discolor and proved to be very suitable for further use in typical polyurethane applications without problems.

[0162] Example 4 (Comparative Experiment) Preparation of ISODI from ISODA by FPP without "Secondary Amine"

[0163] 28.8 g (0.2 mol) of ISODA were phosgenated according to general procedure A. The reaction mixture thus obtained was substantially freed of the solvent on a rotary evaporator under reduced pressure and then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave 15.1 g of a dark brown, highly viscous distillation residue and 26.0 g (yield 66% based on the amine used) of a light-colored distillate, which, according to a combination of analytical methods (NMR, GC-MS), was found to consist of about 98% of ISODI. The titrated NCO content was 42.2%, the AC / HC value was 904 / 1548 ppm. After a few days, the previously almost colorless distillate changed color significantly and turned dark brown after storage for several weeks at room temperature with exclusion of air. The product is not suitable for further problem-free use in typical polyurethane applications.

[0164] Example 5 (according to the invention): CoPg-FPP of IDDA (first amine) and IPDA (second amine)

[0165] According to general procedure A, 5.8 g (0.04 mol) of IDDA and 33.7 g (0.16 mol) of IPDA were phosgenated. The reaction mixture thus obtained was substantially freed of the solvent on a rotary evaporator under reduced pressure and then immediately subjected to a "trap-to-trap" distillation at 0.1 mbar and a bath temperature of 120-180° C. This gave only 3.6 g of a dark brown, highly viscous distillation residue and 40.6 g of a light-colored distillate, which, according to a combination of analytical methods (NMR, GC-MS), consisted of about 16.7% of ISODI and 83.3% of IPDI (yields of 86% and 95% based on the amine used). The AC / HC content of the mixture was 42 / 132 ppm.

[0166] Example 6 (Comparative Experiment) Preparation of H from PACM20 by GPP according to General Procedure B 12 -MDI (experiments a and b) and preparation of IPDI from IPDA (experiment c)

[0167] a) In a gas phase tubular reactor preheated to 350° C., 141 g of PACM 20 (0.67 mol) were reacted with 580 g of phosgene (5.86 mol) at 500 mbar for 2 hours. The two material streams were each evaporated at the same pressure in a heat exchanger and heated to 350° C. For better evaporation of the amine, 60 l / h of nitrogen was passed through the amine evaporator as a carrier gas stream. Immediately after the start of the reaction, the formation of crusts and deposits was clearly observed at the amine inlet and in the reaction tube. The precise final weighing after the experiment showed 8 g of solids.

[0168] b) In a gas phase tubular reactor preheated to 450° C., 139 g of PACM 20 (0.66 mol) were reacted with 581 g of phosgene (5.87 mol) at 500 mbar for 2 hours. The two substance streams were each evaporated at the same pressure in a heat exchanger and heated to 450° C. For better evaporation of the amine, 60 l / h of nitrogen were passed as carrier gas through the amine evaporator. Compared with Example 6a, significantly less crusting and deposits were formed. After the experiment, only very thin deposits were visible on the walls in the reactor, which were reweighed to 1.3 g.

[0169] c) In a gas phase tubular reactor preheated to 350° C., 170 g of IPDA (1.0 mol) were reacted with 622 g of phosgene (6.29 mol) at 500 mbar for 2 hours. The two material streams were each evaporated in a heat exchanger at 500 mbar and heated to 350° C. For better evaporation of the amine, 30 l / h of nitrogen were passed through the amine evaporator. After the start of the reaction, only a small amount of crusting and deposit formation was observed at the amine inlet and in the reaction tube; it was determined to be 0.5 g after the experiment.

[0170] pass 1 The reaction mixtures obtained under a and b were studied by H NMR, where it was found that in addition to the solvent and H 12 -MDI, it also contains a corresponding proportion of olefins, which can be identified as cyclohexenylmethylcyclohexyl isocyanate (multiple isomers) by GC-MS. In Example 6b, this undesirable by-product is based on the target compound H 12 -MDI ratio is significantly lower than in 6a: 67:1 compared to 4:1 (H 12 -MDI mass: olefin mass).

[0171] After removal of the solvent as described in Examples 2-5 and subsequent "trap-to-trap" distillation, 6.15 g of a dark brown, highly viscous distillation residue and 140.4 g of a light-colored distillate were obtained in a), which after subsequent fractionation through a 40 cm long vacuum-jacketed Vigreux column (internal diameter about 25 mm) gave 123.6 g of a constant-boiling, colorless main fraction (NCO content only 30.3%) (H 2 O, based on the PACM 20 used). 12 -MDI yield <70%). In b), 2.8 g of residue and 163 g of final distillate were obtained, whose NCO content was 31.8% (based on the PACM 20 used, H 12 -MDI yield 93%).

[0172] Example 7 (according to the invention): CoPg-GPP of TEFUDA (first amine or amine 1) and PACM 20 (second amine or amine 2) by GPP according to General Procedure B

[0173] According to Example 6b, a mixture of TEFUDA (amine 1) and PACM 20 (amine 2) was phosgenated according to general procedure B. In this case, pure amine 2 (about 0.335 mol / h) was metered in at the beginning of the experiment with a phosgene molar excess of about 250%. After an experimental time of 30 minutes, amine 1 was replenished so that an amine mixture consisting of 25 mol % of amine 1 and 75 mol % of amine 2 was metered in. In a further experiment, the concentration of amine 1 was increased further so that an amine mixture containing 50 mol % of amine 1 / 50 mol % of amine 2 and 75 mol % of amine 1 / 25 mol % of amine 2 was used. A total of 782.6 g (6 mol) of TEFUDA and 1431.1 g (6.8 mol) of PACM 20 were processed. The amounts metered in, the phosgene excess used and the operating times can be seen from the table below.

[0174]

[0175] The crude product after dephosgene is passed through 1 The samples were studied by H-NMR spectroscopy and then combined. 12 - The MDI:Olefin ratio shows that the proportion of undesirable compounds is again significantly reduced in all experimental runs 7-1 to 7-7, averaging only 146: 1, compared to the better comparative example 6b. No significant differences in this ratio were observed in experimental runs 7-1 to 7-7.

[0176] The post-treatment was carried out as described in Example 6, except that in order to finally separate TEFUDI and H 12 -MDI, using a more efficient column (40 cm packed column, inner diameter about 25 mm, packing: #1 Interpack), only 53.9 g of dark brown, high viscosity distillation residue and 980.5 g of TEFUDI and 1674.2 g of H 12 - MDI, which are in each case light-colored liquids consisting of >99% TEFUDI or H 12 -MDI (isomer mixture) composition (yields based on the amine used are 90% and 94%, respectively). AC / HC contents are 35 / 318 ppm (TEFUDI) and 29 / 87 ppm (H 12 -MDI). No discoloration was observed even after storage for several weeks with exclusion of air.

[0177] Example 8 (according to the invention): ISODA (first amine or amine 1) and PACM 20 (second amine or amine 2) were subjected to CoPg-GPP by GPP according to general procedure B.

[0178] According to the operating procedure in Example 7, a mixture of ISODA (amine 1) and PACM 20 (amine 2) was phosgenated in a gas phase phosgenation unit. In experiment 8-1, pure amine 2 (about 0.5 mol / h) was metered in at a phosgene molar excess of about 250% at the beginning of the experiment. After 30 minutes of the experiment time, amine 1 was replenished so that an amine mixture consisting of 25 mol% of amine 1 and 75 mol% of amine 2 was metered in. A stepwise increase of 25 mol% was carried out twice in total after another 30 minutes each, so that an amine mixture consisting of 75 mol% of amine 1 and 25 mol% of amine 2 was metered in 2 hours after the start of the experiment, which then remained constant until the end of the experiment after a total operating time of 6.25 hours. In the subsequent experiment, an amine mixture consisting of 50 mol% of amine 1 and 50 mol% of amine 2 was metered in immediately after the first stage with pure amine 2, and this state was maintained until the end of the experiment. In addition, the phosgene excess decreased from one experiment to the next, while the reactor deposits tended to be less. The amounts metered in, the phosgene excess used and the run times in the individual experiments can be gathered from the table below. A total of 1353.9 g (9.39 mol) of ISODA and 915.0 g (4.35 mol) of PACM 20 were processed.

[0179]

[0180] The crude product after dephosgene is passed through 1 The samples were studied by H-NMR spectroscopy and then combined. 12 - MDI:Olefin Ratio The ratio of undesirable compounds was found to be again significantly reduced compared to the better comparative example 6b, averaging only 127: 1. No significant differences were observed with respect to this ratio in experimental runs 8-1 to 8-5 either.

[0181] Work-up according to Example 7 gave only 60.1 g of a dark brown, highly viscous distillation residue as well as 1795.8 g of ISODI and 993.1 g of H 12 -MDI as a light-colored liquid, which, according to a combination of analytical methods (NMR, GC-MS), consists of >99% ISODI or H 12 -MDI (isomer mixture) composition (yields based on the amine used are 97.5% and 87.0%, respectively). AC / HC contents are 27 / 178 ppm (ISODI) and 15 / 152 ppm (H 12 -MDI). No discoloration was observed for both products obtained according to the invention even after storage for several weeks at room temperature with exclusion of air.

[0182] Example 9

[0183] a) Two comparative experiments of OBDA GPP

[0184] b) According to the present invention: OBDA (first amine) and IPDA (second amine) were subjected to CoPg-GPP by GPP according to General Procedure B

[0185] a)

[0186] In two separate experiments, OBDA and phosgene were reacted at 500 mbar in a gas phase tubular reactor preheated to 350° C. The two substance streams were evaporated in a heat exchanger at 500 mbar and heated to 350° C. In order to evaporate the amine better, 30 l / h of nitrogen were passed through the amine evaporator as carrier gas. In the first comparative experiment, 325 g of OBDA (3.1 mol) were reacted with 1376 g of phosgene (13.9 mol) within 3.8 hours. In the second comparative experiment, 312 g of OBDA (3.0 mol) and 1219 g of phosgene (12.3 mol) were metered in within 3.5 hours, wherein a reactor deposit of 9 g was determined after the experiment.

[0187] Work-up as described in Example 6 gave 185 g of a dark brown, highly viscous distillation residue and 723.0 g of OBDI as a light-colored liquid, which, according to a combination of analytical methods (NMR, GC-MS), consisted of >98% OBDI (yield 76%, based on the amine used). The AC / HC content was 90 / 793 ppm. After storage at room temperature for several weeks with exclusion of air, the product changed color significantly. The color value increased from an initial 8 APHA immediately after the distillation work-up to 520 APHA after 3 weeks.

[0188] b)

[0189] According to Example 6c, an amine mixture consisting of 118.4 g OBDA (1.14 mol) and 355.3 g IPDA (2.09 mol) was metered into a gas phase tubular reactor preheated to 350° C. over a period of 6 hours and reacted with 2223 g phosgene (22.47 mol) at an equipment pressure of 500 mbar. The two material streams were each evaporated in a heat exchanger at 500 mbar and heated to 350° C. For better evaporation of the amine, 30 l / h of nitrogen were passed through the amine evaporator. Downstream of the reactor, the reaction mixture was quenched in boiling o-dichlorobenzene and dephosgenated by nitrogen stripping. After the experiment, it was determined that 4 g of solids were formed at the amine inlet and in the reaction tube.

[0190] Work-up according to Example 6 gave only 12 g of a dark brown, highly viscous distillation residue, 169 g of OBDI and 442 g of IPDI as light-colored liquids which, according to a combination of analytical methods (NMR, GC-MS), consisted of >99% OBDI or IPDI (isomer mixture) (yield 95% each, based on the amine used). The AC / HC contents were 19 / 114 ppm (OBDI) and 12 / 212 ppm (IPDI), respectively. No discoloration was observed for the two products obtained according to the invention even after storage for several weeks at room temperature with exclusion of air.

[0191] Example 10 (according to the invention): CoPg-GPP of ISODA (first amine) and OBDA (second amine)

[0192] First, 42.2 g of OBDA (0.4 mol) and 152 g of phosgene (1.54 mol) were metered into a gas phase tubular reactor preheated to 350° C. over a period of 30 minutes. An amine mixture consisting of 54.0 g of ISODA (0.37 mol) and 117.3 g of OBDA (1.13 mol) was then metered in over a period of 3 hours and reacted with 933 g of phosgene (9.43 mol) at an equipment pressure of 500 mbar. The two material streams were each evaporated in a heat exchanger at 500 mbar and heated to 350° C. For better evaporation of the amine, 60 l / h of nitrogen were passed through the amine evaporator as a carrier gas stream. Downstream of the reactor, the reaction mixture was quenched in boiling o-dichlorobenzene and dephosgenated by nitrogen stripping. The solid formed at the amine inlet and in the reaction tube, determined after the experiment, was 8.3 g.

[0193] Work-up as described in Example 6 gave only 16.6 g of a dark brown, highly viscous distillation residue, 49.8 g of ISODI and 199.9 g of OBDI as light-colored liquids which, depending on the combination of analytical methods (NMR, GC-MS), consisted of >99% ISODI or OBDI (yields of 68% and 84%, respectively, based on the amine used). No discoloration was observed for both products obtained according to the invention even after storage for several weeks at room temperature with exclusion of air.

[0194] Numerous experiments with the reaction of TEFUDA, IDDA or ISODA by GPP without any "amine 2" failed after a maximum run time of 60 minutes. Solid lumps formed and the pressure increase in the plant necessitated shutdowns after unacceptably short run times. The ISODI formed in very poor yields was of completely unacceptable quality and could only be purified with great effort.

Claims

1. A process for producing isocyanates by phosgenation of the corresponding amines, wherein an amine mixture formed from at least one first amine and at least one second amine different from the first amine is reacted with phosgene to provide a reaction mixture, It is characterized in that ■ the first amine contains at least one ether group; and ■ the second amine is selected from the group comprising or consisting of aminoalkanes having 5 to 15 hydrocarbon atoms without ether groups; or ■ the first amine contains at least one cyclic ether group; and ■ The second amine contains at least one open-chain ether group and no cyclic ether groups.

2. The method according to claim 1, characterized in that The first amine containing at least one ether group has the general formula X-(-R 1 -NH m ) n The structure of -X is H, NH m or C(R 2 ) p ; -R 1 is an optionally substituted and / or heteroatom-containing aliphatic, (cyclo)aliphatic or aromatic radical, preferably having up to 10 carbon atoms, wherein R 1 Containing at least one ether group; -R 2 is H or an optionally substituted and / or heteroatom-containing aliphatic, (cyclo)aliphatic or aromatic group, which preferably has up to 10 carbon atoms; -m is 1 or 2; -n is 1, 2, or 3; and -p is 1, 2, or 3.

3. The method according to claim 1 or 2, characterized in that: The first amine containing at least one ether group, the first amine containing at least one cyclic ether group, the second amine containing or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms and / or the second amine containing at least one open-chain ether group and containing no cyclic ether group is a diamine.

4. The method according to any one of the preceding claims, characterized in that The first amine containing at least one ether group is selected from (tetrahydrofuran-2,5-diyl)dimethylamine, 3,6-diaminohexahydrofurano[3,2-b]furan, 3,6-bis(aminomethyl)hexahydrofurano[3,2-b]furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2, 2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine; di(aminoethyl)ethers, especially 2,2'-oxybis(ethyl-1-amine), 1,1'-oxybis(propan-2-amine), 2-(2-aminoethoxy)propan-1-amine, 2,2'-oxybis(propan-1-amine) and 2-(2-aminopropoxy)propan-1-amine, di(aminopropyl)ether or mixtures thereof and / or The first amine containing at least one cyclic ether group is selected from (tetrahydrofuran-2,5-diyl)dimethylamine, 3,6-diaminohexahydrofurano[3,2-b]furan, 3,6-bis(aminomethyl)hexahydrofurano[3,2-b]furan, furan-2,5-diyldimethylamine, (methane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (methane-2,2-diylbis(furan-5,2-diyl))dimethylamine, (propane-2,2-diylbis(tetrahydrofuran-5,2-diyl))dimethylamine, (propane-2,2-diylbis(furan-5,2-diyl))dimethylamine or a mixture thereof.

5. The method according to any one of the preceding claims, characterized in that The second amine comprising or consisting of an aminoalkane having 5 to 15 hydrocarbon atoms is selected from the group consisting of: 1,5-diaminopentane; 1,6-diaminohexane; 1-amino-3,5,5-trimethyl-5-aminomethylcyclohexane; amino-[(aminocyclohexyl)methyl]cyclohexane, in particular 4,4'-methylenebis(cyclohexane-1-amine), 2-((4-aminocyclohexyl)methyl)cyclohexane-1-amine and 2,2'-methylenebis(cyclohexane-2-amine). cyclohexane-1,2-diamine, cyclohexane-1,3-diamine and cyclohexane-1,4-diamine; methyldiaminocyclohexanes, especially 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine, 4,4'-methylenebis(2-methylcyclohexane-1-amine); or mixtures thereof.

6. The method according to any one of the preceding claims, characterized in that The second amine containing at least one open-chain ether group and no cyclic ether group is selected from the group consisting of di(aminoethyl)ether, di(aminopropyl)ether, 1,8-diamino-1,5,8-trimethyl-3,6-dioxaoctane, 1,11-diamino-1,5,8,11-tetramethylundecane, 1,8-diamino-3,6-dioxaoctane, 1,10-diamino-4,7-dioxadecane, 1,12-diamino-4,9-dioxadodecane, 1,14-diamino-3,10-dioxatetradecane, 1,13-diamino-4,7,10- trioxatridecane, 1,7-diamino-2,6-dioxa-4-aminomethoxyheptane, 1-amino-2-oxa-3,3-bis(aminomethoxy)hexane, 1,9-diamino-3,7-dioxa-5-(1-amino-2-ethoxy)-nonane, 1-amino-3-oxa-4,4-bis(1-amino-2-ethoxy)heptane, 1,11-diamino-4,8-dioxa-6-(1-amino-5-oxabutyl)undecane, 1-amino-4-oxa-5,5-bis(1-amino-5-oxabutyl)octane or a mixture thereof.

7. The method according to any one of the preceding claims, characterized in that ■ The mass proportion of the first amine is 5.0 to 95.0% by weight, preferably 10.0 to 80.0% by weight, and ■ The mass proportion of the second amine is 95.0 to 5.0% by weight, preferably 90.0 to 20.0% by weight, more preferably 80.0 to 20.0% by weight, The molar ratio of phosgene and / or phosgene to the amino groups of the amines in the amine mixture is ≧1:1 to ≦5:1, preferably >1:1 to ≦3:1, based on the total weight of the amine mixture.

8. The method according to any one of the preceding claims, characterized in that An inert substance is used in the reaction, wherein the inert substance is selected from: ■Inert gases, especially nitrogen, argon or mixtures thereof; ■ an inert solvent, in particular an aromatic hydrocarbon, preferably chlorobenzene, o-dichlorobenzene, toluene, xylene or a mixture thereof; ■ Or a mixture of the above inert gases and inert solvents.

9. The method according to any one of the preceding claims, characterized in that The isocyanate corresponding to the first amine and / or the isocyanate corresponding to the second amine is separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin-film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained individually or as an isocyanate mixture.

10. The method according to any one of claims 1 to 8, characterized in that The isocyanate corresponding to the first amine and / or the isocyanate corresponding to the second amine is separated from the reaction mixture, wherein the separation is preferably carried out by distillation, in particular thin-film distillation, extraction, crystallization, recrystallization or a combination thereof, and the respective isocyanates are obtained as an isocyanate mixture.

11. The method according to claim 9 or 10, characterized in that: The content of acidic chlorine compounds in the separated one or more isocyanates or the isocyanate mixture is determined according to ISO 15028:2014 standard and is 1 to 100 ppm, preferably 2 to 80 ppm, more preferably 5 to 50 ppm, and / or the content of hydrolyzable chlorine in the separated one or more isocyanates or the isocyanate mixture is determined according to ISO 15028:2014 standard and is 1 to 500 ppm, preferably 5 to 100 ppm.

12. Use of an amine mixture formed from at least one first amine and at least one second amine different from the first amine in a process for producing the corresponding isocyanates by phosgenation according to any one of claims 1 to 11 for reducing the content of acidic chlorine compounds and / or the content of hydrolyzable chlorine in the corresponding isocyanates obtained during the production process.

13. A product obtainable or obtained by a method as claimed in any one of claims 1 to 8, 10 or 11, preferably directly obtainable or obtained by a method as claimed in any one of claims 1 to 8, 10 or 11.

14. Use of the product according to claim 13 and / or the isocyanates or isocyanate mixtures obtained or obtainable by the process according to claim 10 or 11 as components for the production of polyurethanes, in particular polyurethane foams, polyurethane coatings and polyurethane adhesives, pharmaceuticals, in particular active substances, and auxiliaries, in particular wet strength finishing auxiliaries, emulsifiers and thickeners for paper and other cellulosic products.

15. A phosgenation plant for carrying out the method according to claims 1 to 11, comprising or consisting of (a) at least one phosgene plant for the continuous supply of phosgene, optionally in combination with an inert substance, (b) optionally, an inert material device for providing an inert material, (c) at least one amine plant for continuously providing an amine mixture, optionally in combination with an inert substance, (d) a phosgenation reactor for mixing phosgene with an amine mixture and optionally an inert substance and reacting the amine mixture with phosgene, It is characterized in that The amine device comprises a first storage container for a first amine and a second storage container for a second amine, as well as a metering unit for variably adjusting the mass ratio of the first amine and the second amine independently of one another, and optionally a mixing unit for mixing the first amine and the second amine to form an amine mixture.

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