Process for cleavage of aminobenzanilide to aniline

Abstract

The present invention relates to a process for cleavage of aminobenzanilide to aniline, in which a starting reaction mixture containing aminobenzanilide and water, wherein aminobenzanilide and water in the starting reaction mixture are in a mass ratio of at most 11.7:1, is reacted with release of carbon dioxide and formation of aniline in the presence of a catalyst at a temperature of 210°C to 350°C, wherein the catalyst comprises a metal oxide which has the following material properties: (α) a local absorption maximum in an IR spectrum of pyridine adsorbed on the metal oxide in a wavelength range of 1435 cm-1 to 1453 cm-1 and (ß) a concentration of Lewis-acidic centres of at least 3.0 μmol / g, preferably at least 5.0 μmol / g, and in particular of at most 2000 μmol / g, preferably at most 500 μmol / g.

Description

[0001] 2024PF30059 - Abroad

[0002] - 1 -

[0003] METHOD FOR THE CHILLED AMPINOBENZANILIDE TO ANILINE

[0004] The work that led to the present invention was financially supported by the German Federal Ministry of Food and Agriculture under grant number 2221NR073X.

[0005] The present invention relates to a process for the cleavage of aminobenzanilide to aniline, in which a starting reaction mixture containing aminobenzanilide and water, wherein aminobenzanilide and water are present in the starting reaction mixture in a mass ratio of at most 11.7 : 1, is reacted with the release of carbon dioxide and the formation of aniline in the presence of a catalyst at a temperature of 210 °C to 350 °C, wherein the catalyst comprises a metal oxide having the following material properties:

[0006] (a) a local absorption maximum in an IR spectrum on the pyridine adsorbed by the metal oxide in a wavelength range of 1435 cm 1 up to 1453 cm -1 and

[0007] (ß) a concentration of Lewis acidic centers of at least 3.0 .mol / g, preferably at least 5.0 .mol / g and in particular of at most 2000 .mol / g, preferably at most 500 .mol / g.

[0008] Aniline is an important intermediate, for example, in the production of di- and polyisocyanates of the diphenylmethane series (MDI), and is currently produced on an industrial scale primarily by the catalytic hydrogenation of nitrobenzene in the gas or liquid phase (see, for example, EP-A-0 696573, EP-A-0696574, EP-A-1 882 681 and WO 2013 / 139737 Al). In this reaction, in addition to the target product aniline, by-products such as phenol or aminophenols are also formed, which must be removed before the aniline can be used in subsequent processes.

[0009] In addition to this established method, a two-step process for the production of aniline has recently been developed. In this process, aminobenzoic acid is first produced via a biological process and then decarboxylated to aniline in a second step. This is described, for example, in international patent applications WO 2015 / 124686 Al and WO 2015 / 124687 Al. The starting compound, aminobenzoic acid, can, of course, also be obtained chemically. One suitable synthetic route is, for example, the reaction of phthalimide with sodium hypochlorite. Phthalimide, in turn, can be obtained from phthalic anhydride and ammonia.

[0010] The decarboxylation of aminobenzoic acid produces aminobenzanilides as byproducts, e.g., 2-aminobenzanilide during the decarboxylation of ortho- 2024PF30059 - Abroad

[0011] - 2 -

[0012] Aminobenzoic acid (anthranilic acid). These byproducts must also be separated as far as possible before further use of the aniline. Current state of the art does not yet give this problem the necessary attention.

[0013] WO 2015 / 124686 describes the decarboxylation of fermentatively or chemically produced anthranilic acid by extraction of the aniline formed in the decarboxylation with a foreign organic solvent (an alcohol, phenol, amide, ether, or aromatic hydrocarbon; 1-dodecanol is specifically highlighted as a suitable solvent). Acidic catalysts such as zeolites or basic catalysts such as Mg-Al hydrotalcite (MgAlzfCOaJfOHjig - AHzO, corresponding to a calculated mass fraction of "Al₂O₃" of 16.88%) are described as catalysts for the decarboxylation.

[0014] WO 2015 / 124687 describes the decarboxylation of fermentatively produced anthranilic acid, among other things, in water or in a foreign organic solvent, in particular 1-dodecanol, optionally in a mixture with aniline (see page 18, lines 28 and 29). Furthermore, this document also describes the possibility of carrying out the decarboxylation in aniline (without 1-dodecanol; see Figures 35 and 37 to 38 and the corresponding text), optionally in the presence of 10 wt% water (see Figure 36 and the corresponding text).

[0015] WO 2018 / 002088 Al describes a process in which aminobenzoic acid is decarboxylated in a mixture with crude aniline. The crude aniline is derived from the process itself, by recycling a portion of the product stream into the process instead of subjecting it to purification. Catalysts for the decarboxylation include aqueous acids such as sulfuric acid, nitric acid, and hydrochloric acid; solid acids such as zeolites and Si-Ti molecular sieves; solid bases such as hydroxyapatites and hydrotalcites; and polymeric acids such as ion exchange resins (especially Amberlyst).

[0016] WO 2020 / 020919 Al describes the decarboxylation of aminobenzoic acid using only aniline as a catalyst. The use of other catalysts is deliberately omitted.

[0017] WO 2022 / 253890 describes the production of aniline or an aniline derivative by the decarboxylation of aminobenzoic acid in the presence of a heterogeneous metal oxide catalyst. This catalyst contains a mass fraction of Al₂O₃ of 40.0 to 100% based on the total mass of the metal oxides, with the mass fraction of Al₂O₃ of the inorganic heterogeneous metal oxide catalyst being 25 to 100%. The described catalysts enable rapid decarboxylation, which in turn leads to a reduced formation of the byproduct aminobenzanilide. Aminobenzanilide is formed in increased amounts whenever aminobenzoic acid and aniline react together under increased [2024PF30059 - Abroad]

[0018] - 3 -

[0019] Temperature is a factor. The faster the aminobenzoic acid reacts, the lower the formation of the undesired byproduct. This is evident, among other things, from Table 2 of WO 2022 / 253890 Al: Those catalysts that, under otherwise identical conditions (185 °C, 20 min reaction time), yield the highest conversions of anthranilic acid (ortho-aminobenzoic acid) also result in the best aniline selectivities and the lowest levels of aminobenzanilide. Or, put another way: A low aminobenzanilide content in the product is achieved by slowing its formation. This document does not address the cleavage of those aminobenzanilide whose formation cannot be prevented despite the improved catalysts.For example, an increase in temperature under otherwise identical conditions (5.0% water, 60 min reaction time, Pural®MG30 catalyst, the most active of the catalysts disclosed in WO 2022 / 253890 Al) does not lead to a reduction in the aminobenzanilide content of the product (see Table 5, Examples 52, 55, 58 and 61), as would be expected if significant aminobenzanilide suppression were to occur. Rather, WO 2022 / 253890 Al attempts to suppress the formation of aminobenzanilide by adding water (see Examples 48 to 50 in Table 4 and Examples 51 and 52 as well as 54 and 55 in Table 5). The use of TiOz as a catalyst does not lead to a reduction in the aminobenzanilide content compared to purely thermal decarboxylation, but actually to an increase (see examples 1 and 2, Table 2).This also indicates that low aminobenzanilide levels in the product are achieved in the process according to WO 2022 / 253890 Al by suppressing the formation of aminobenzanilide, but once formed, aminobenzanilide is not cleaved under the applied conditions.

[0020] In WO 2023 / 194110 Al, the production of aniline or an aniline derivative is described by the decarboxylation of aminobenzoic acid in a reactor at a reaction temperature in the range of 170 °C to 350 °C, the reaction taking place below the boiling point of aniline and a gas stream containing aniline and CO2 being removed from the reaction area.

[0021] None of the previously described methods are entirely satisfactory with regard to suppressing the byproduct aminobenzanilide (which increases the proportion of aniline formed and also facilitates its quantitative isolation by distillation purification – as a result of reduced aniline losses during the necessary high-boiling removal from the bottom). In particular, the often unavoidable formation of amides during the storage of aminobenzoic acid-containing reactant mixtures in feed vessels at elevated temperatures makes a technology for the cleavage of aminobenzanilide desirable, as does the suppression of its formation during decarboxylation, which is the focus of the prior art (see in particular the discussion of WO 2022 / 253890 Al further 2024PF30059 - Foreign).

[0022] - 4 - above). This would significantly contribute to an improved production of aniline or aniline derivatives by decarboxylation of, preferably fermentatively produced, aminobenzoic acid.

[0023] Taking this need into account, the present invention relates to a process for the cleavage of aminobenzanilide (by reaction with water first to aminobenzoic acid and aniline and finally by decarboxylation of the aminobenzoic acid) to (further) aniline (as well as carbon dioxide), comprising the steps:

[0024] (A) Providing a starting reaction mixture containing aminobenzanilide, preferably 2-aminobenzanilide and / or 4-aminobenzanilide, particularly preferably 2-aminobenzanilide, and water, wherein aminobenzanilide (if different isomers are present: the sum of all isomers) and water are present in the starting reaction mixture in a mass ratio of at most 11.7 : 1 and particularly in a mass ratio of 0.005 : 1 to 11.7 : 1; and

[0025] (B) Reacting the initial reaction mixture with release of carbon dioxide (by decarboxylation of the aminobenzoic acid initially formed alongside aniline) and formation of (further) aniline in the presence of a catalyst at a temperature of 210 °C to 350 °C, wherein the catalyst comprises (and in particular is) a metal oxide having the following material properties:

[0026] (a) a local absorption maximum in an IR spectrum (measured as explained in the example section) on the pyridine adsorbed by the metal oxide in a wavelength range of 1435 cm -1 up to 1453 cm -1 and

[0027] (β) a concentration of Lewis acidic centers of at least 3.0 mol / g, preferably at least 5.0 mol / g and in particular of at most 2000 mol / g, preferably at most 500 mol / g (determined by quantitative IR spectroscopy using the method described in the example section).

[0028] In the terminology of the present invention, “aminobenzanilide” is used as a collective term for the three isomers 2-aminobenzanilide, 3-aminobenzanilide, and 4-aminobenzanilide. Insofar as the present invention relates to the cleavage of such aminobenzanilide that is obtained as a byproduct of the decarboxylation of aminobenzoic acid, the isomer of aminobenzoic acid naturally corresponds to the isomer of aminobenzanilide, i.e., in the decarboxylation of 2024PF30059 - Abroad

[0029] - 5 - Decarboxylation of ortho-aminobenzoic acid yields 2-aminobenzanilide, decarboxylation of meta-aminobenzoic acid yields 3-aminobenzanilide, and decarboxylation of para-aminobenzoic acid yields 4-aminobenzanilide. The ortho- and para-isomers of aminobenzoic acid are preferred, as their decarboxylation produces 2-aminobenzanilide and 4-aminobenzanilide, respectively, as byproducts.

[0030] Within the scope of the present invention, all pH values ​​refer to the temperature at which the corresponding step (e.g., a fermentation to provide aminobenzoic acid) is carried out and can be easily measured with a glass electrode.

[0031] The following is a brief summary of various possible embodiments of the invention:

[0032] In a first embodiment of the process according to the invention, which can be combined with all other embodiments, the local absorption maximum of the catalyst used in step (B) is in the IR spectrum of adsorbed pyridine in the wavelength range of 1442 cm. 1 up to 1448 cm" 1 lies and the concentration of Lewis acidic centers ranges from 3.0 pmol / g to 500 pmol / g.

[0033] In a second embodiment of the method according to the invention, which is a special embodiment of the first embodiment, the concentration of Lewis acidic centers according to (β) is 3.0 pmol / g to 200 pmol / g.

[0034] In a third embodiment of the process according to the invention, which can be combined with all other embodiments, the catalyst used in step (B) contains a main component in a mass fraction of 70% to 100% based on its total mass and is optionally doped with a minor component, wherein the minor component, if present, is present in a mass fraction of 0.5% to 30% based on the total mass of the catalyst, wherein the main component is selected from a metal oxide of group III or a metal oxide of group IV, and wherein the minor component, if present, is selected from a metal oxide or semimetal oxide of group IV, a metal oxide of group IV, a metal oxide of group VI, a metal oxide of a lanthanide, or a mixture thereof.

[0035] In a fourth embodiment of the method according to the invention, which is a special embodiment of the third embodiment, the main component is TiOz or ZrOz. 2024PF30059 - Abroad

[0036] - 6 - In a fifth embodiment of the method according to the invention, which is a special embodiment of the third and fourth embodiments, the accessory component is an oxide of silicon, zirconium, hafnium, tungsten, cerium or a mixture of two or more thereof.

[0037] In a sixth embodiment of the method according to the invention, which can be combined with all other embodiments, step (B) is carried out at a temperature of 230 °C to 350 °C, preferably 230 °C to 300 °C.

[0038] In a seventh embodiment of the method according to the invention, which can be combined with all other embodiments, step (B) is carried out at a pressure in a gas space above the reacting initial reaction mixture of 1.0 bar to 200 bar, preferably 5.0 bar to 100 bar.

[0039] In an eighth embodiment of the method according to the invention, which can be combined with all other embodiments, step (B) is carried out for a period of 5 min to 360 min, preferably 15 min to 210 min.

[0040] In a ninth embodiment of the method according to the invention, which can be combined with all other embodiments, provided that these are not exclusively directed to the cleavage of different isomers of 2-aminobenzanilide, the aminobenzanilide is 2-aminobenzanilide.

[0041] In a tenth embodiment of the method according to the invention, which can be combined with all other embodiments, provided that these are not exclusively directed to the cleavage of different isomers of 4-aminobenzanilide, the aminobenzanilide is 4-aminobenzanilide.

[0042] In an eleventh embodiment of the method according to the invention, which can be combined with all other embodiments, provided that these are not exclusively directed to the cleavage of 3-aminobenzanilide, the aminobenzanilide is a mixture containing, in particular consisting of or at least substantially consisting of, 2-aminobenzanilide and 4-aminobenzanilide.

[0043] In a twelfth embodiment of the method according to the invention, which can be combined with all other embodiments, step (A) comprises:

[0044] (A)(1) Providing aminobenzoic acid, and

[0045] (A)(ll) Reaction of aminobenzoic acid with release of carbon dioxide to form a mixture containing (in particular consisting of, or at least substantially consisting of) aniline and aminobenzanilide. 2024PF30059 - Foreign

[0046] - 7 - In a thirteenth embodiment of the method according to the invention, which is a special embodiment of the twelfth embodiment, step (A)(ll) is carried out at a temperature of 150 °C to 300 °C, preferably 160 °C to 280 °C, particularly preferably 180 °C to 240 °C, most particularly preferably 180 °C to 230 °C.

[0047] In a fourteenth embodiment of the method according to the invention, which is a special embodiment of the thirteenth embodiment, step (A( 11 ) is carried out at a temperature of 180 °C to 230 °C and step (B) is carried out at a temperature of > 230 °C to 300 °C (in particular from 231 °C to 300 °C, preferably from 232 °C to 300 °C).

[0048] In a fifteenth embodiment of the process according to the invention, which is a special embodiment of the twelfth to fourteenth embodiments, step (A)(1) comprises a fermentation of a raw material containing a fermentable carbon-containing compound and a nitrogen-containing compound in the presence of microorganisms.

[0049] In a sixteenth embodiment of the method according to the invention, which is a further special embodiment of the twelfth to fourteenth embodiments, step (A)(1) comprises a chemical synthesis of aminobenzoic acid.

[0050] In a seventeenth embodiment of the method according to the invention, which is a special embodiment of the twelfth to sixteenth embodiments, step (A)(ll) is carried out in the presence of aniline.

[0051] In an eighteenth embodiment of the method according to the invention, which is a special embodiment of the twelfth to seventeenth embodiments and can be advantageously combined with the seventeenth embodiment in particular, step (A)(l I ) is carried out without the addition of an inorganic catalyst.

[0052] In a nineteenth embodiment of the method according to the invention, which is a special embodiment of the twelfth to eighteenth embodiments, step (A)(ll) is carried out in the presence of an inorganic catalyst which differs in at least one of the material properties (a) or (ß) from the catalyst used for step (B).

[0053] In a twentieth embodiment of the method according to the invention, which is a further special embodiment of the twelfth to eighteenth embodiments and can be advantageously combined with the first and second embodiments, step (A)(ll) is carried out in the presence of an inorganic catalyst which has the material properties (a) and (ß).

[0054] In a twenty-first embodiment of the process according to the invention, which is a particular embodiment of the twentieth embodiment, the inorganic catalyst used in step (A)(11) differs from the catalyst used in step (B). 2024PF30059 - Abroad

[0055] - 8 - In a twenty-second embodiment of the process according to the invention, which is a particular embodiment of the nineteenth to twenty-first embodiments and can be advantageously combined with the nineteenth and twenty-first embodiments, the inorganic catalyst used in step (A)(ll) is a heterogeneous metal oxide catalyst containing a mass fraction of AI2O3 of 40.0% to 100%, preferably 50.0% to 100%, particularly preferably 60.0% to 100%, based on the total mass of the metal oxides, wherein the mass fraction of AI2O3 based on the total mass of the heterogeneous metal oxide catalyst is 25% to 100%.

[0056] In a twenty-third embodiment of the process according to the invention, which is a particular embodiment of the twenty-second embodiment, the inorganic heterogeneous metal oxide catalyst contains MgO in a mass fraction of 1.0% to 60.0% based on the total mass of the metal oxides.

[0057] In a twenty-fourth embodiment of the process according to the invention, which is a special embodiment of the twenty-second and twenty-third embodiments, the inorganic heterogeneous metal oxide catalyst contains SiC>2 in a mass fraction of 1.0% to 30.0% based on its total mass.

[0058] In a twenty-fifth embodiment of the process according to the invention, which is a particular embodiment of the twenty-second to twenty-fourth embodiments, it comprises, in particular, the AI2O3 of the inorganic heterogeneous metal oxide catalyst Y-AI2O3 or qA^Os used in step (A)(l I).

[0059] In a twenty-sixth embodiment of the method according to the invention, which is a special embodiment of the twelfth to twenty-fifth embodiments, step (A)(l I) and step (B) are carried out in different reactors.

[0060] In a twenty-seventh embodiment of the process according to the invention, which is a particular embodiment of the twenty-sixth embodiment, the mixture obtained in step (A)(ll) containing (in particular consisting of or at least substantially consisting of) aniline and aminobenzanilide is added to water before carrying out step (B) and optionally freed from any solids that may be present, in particular by filtration.

[0061] In a twenty-eighth embodiment of the process according to the invention, which is a further particular embodiment of the twenty-sixth embodiment, the mixture obtained in step (A)(11), containing (in particular consisting of or at least substantially consisting of) aniline and aminobenzanilide, is distilled to remove aniline before step (B) is carried out, and water is added. It is also optionally freed from any solids that may be present, in particular by filtration. 2024PF30059 - Abroad

[0062] - 9 - In a twenty-ninth embodiment of the process according to the invention, which is a further particular embodiment of the twelfth to twenty-fifth embodiments, steps (A)(1 I ) and (B) are carried out in a common reaction apparatus, which is continuously supplied with aminobenzoic acid at an inlet point and with water at this inlet point and / or at a further inlet point different from the inlet point for aminobenzoic acid, and from which aniline is continuously withdrawn at an outlet point, whereby a reacting mixture is formed in the reaction apparatus, which first flows through a first reaction zone arranged in the reaction apparatus, optionally filled with the catalyst for step (A)(1 I ), and which, after reaching a mass fraction of aminobenzanilide based on the total mass of the reacting mixture in the range of 0.5% to 6.0%, preferably 1.0% to 4.0%,and a mass ratio of aminobenzanilide and water of a maximum of 11.7 : 1 flows through a second reaction zone arranged in the reaction apparatus, filled with the catalyst for step (B), at the end of which the outlet point is arranged.

[0063] In a thirtieth embodiment of the method according to the invention, which is a special embodiment of the twenty-ninth embodiment, the first and the second reaction zone are arranged in two reactors connected in series, which together form the reaction device.

[0064] In a thirty-first embodiment of the method according to the invention, which is a further special embodiment of the twenty-ninth embodiment, the first and second reaction zones are two reaction chambers arranged in series in a common reactor in step (A)(1 I) and step (B), which is identical to the reaction device.

[0065] In a thirty-second embodiment of the process according to the invention, which is a special embodiment of the twelfth to thirty-first embodiments, the aminobenzoic acid is ortho-aminobenzoic acid, so that in step (A)(ll) a mixture containing (in particular consisting of or at least substantially consisting of) aniline and 2-aminobenzanilide is obtained.

[0066] In a thirty-third embodiment of the process according to the invention, which is a further particular embodiment of the twelfth to thirty-first embodiments, the aminobenzoic acid is para-aminobenzoic acid, so that in step (A)(II) a mixture containing (in particular consisting of or at least substantially consisting of) aniline and 4-aminobenzanilide is obtained. 2024PF30059 - Abroad

[0067] - 10 - In a thirty-fourth embodiment of the process according to the invention, which is a further particular embodiment of the twelfth to thirty-first embodiments, the aminobenzoic acid is a mixture containing, in particular consisting of or at least substantially consisting of, ortho-aminobenzoic acid and para-aminobenzoic acid, such that in step (A)( II) a mixture containing (in particular consisting of or at least substantially consisting of) aniline, 2-aminobenzanilide and 4-aminobenzanilide is obtained.

[0068] In a thirty-fifth embodiment of the process according to the invention, which can be combined with all other embodiments, the initial reaction mixture contains a mass fraction of aminobenzanilide of 0.5% to 92% based on its total mass.

[0069] The embodiments and further possible configurations of the invention briefly described above are explained in more detail below. Unless the context clearly indicates otherwise to a person skilled in the art, or unless expressly stated otherwise, all previously described embodiments and the further configurations of the invention can be combined with one another as desired.

[0070] PREPARING THE OUTPUT REACTION MIXTURE (STEP (A))

[0071] In step (A) of the process according to the invention, the starting reaction mixture containing aminobenzanilide to be carried out in step (B) is provided. The term "provided" is to be understood broadly within the scope of the present invention and therefore also includes, in this context, the mere delivery of a starting reaction mixture produced elsewhere.

[0072] In principle, the method of preparing the initial reaction mixture is not limited and can be carried out according to any method known in the prior art. However, the invention is particularly advantageous for the cleavage of aminobenzanilide obtained as a byproduct from the decarboxylation (A)(l I) of aminobenzoic acid provided by any means. The preparation of the aminobenzoic acid can include chemical synthesis or fermentation of a raw material containing a fermentable carbon-containing compound and a nitrogen-containing compound in the presence of microorganisms.

[0073] Regarding chemical synthesis, preferred methods are those that selectively yield the ortho-isomer of aminobenzoic acid (anthranilic acid). The reaction of phthalimide with sodium hypochlorite is one suitable chemical method. Phthalimide itself can be obtained from phthalic anhydride and ammonia. 2024PF30059 - Abroad

[0074] - 11 -

[0075] The chemical production of para-aminobenzoic acid can be carried out via the nitration of toluene with salicylic acid, subsequent oxidation of the resulting para-nitrotoluene with oxygen to para-nitrobenzoic acid and finally reduction to para-aminobenzoic acid with hydrazine.

[0076] Meta-aminobenzoic acid can be produced, for example, starting from methyl benzoate: Nitration of methyl benzoate with nitric acid yields meta-nitrobenzoic acid methyl ester. This methyl ester is then saponified with sodium hydroxide. After neutralization with hydrochloric acid, meta-nitrobenzoic acid is obtained, which is finally reduced to meta-aminobenzoic acid with hydrazine.

[0077] However, according to the invention, it is preferred to produce the aminobenzoic acid by a fermentative process. In this embodiment of the invention, providing aminobenzoic acid comprises the fermentation of a raw material comprising at least one fermentable carbon-containing compound and one nitrogen-containing compound using microorganisms to obtain a fermentation broth containing aminobenzoate and / or aminobenzoic acid. This step can be carried out according to any fermentation process known from the prior art that is suitable for the production of aminobenzoic acid.

[0078] In this embodiment of the present invention, a fermentable carbon-containing compound is understood to be any organic compound or mixture of organic compounds that can be used by the recombinant cells of the microorganism employed to produce aminobenzoic acid. The production of aminobenzoic acid can take place in the presence or absence of oxygen. Fermentable carbon-containing compounds that can additionally serve as an energy and carbon source for the growth of the recombinant cells of the microorganism employed are preferred. Particularly suitable are starch hydrolysate, sugar cane juice, sugar beet juice, and hydrolysates from lignocellulosic raw materials, as well as mixtures thereof (i.e., mixtures of two or more of the aforementioned compounds). Glycerol and citrate compounds, especially carbon monoxide, are also suitable.Suitable nitrogen-containing compounds include, in particular, ammonia gas, ammonia water, ammonium salts (especially inorganic ammonium salts such as ammonium chloride and / or ammonium sulfate, preferably ammonium sulfate), urea or mixtures thereof (i.e., mixtures of two or more of the aforementioned compounds).

[0079] Preferred microorganisms for carrying out fermentation are bacteria or fungi, especially yeasts. Particularly preferred microorganisms include Escherichia coli, Pseudomonas putida, Corynebacterium glutamicum, Ashbya gossypii, and Pichia pastoris. (2024PF30059 - Abroad)

[0080] - 12 -

[0081] Hansenula polymorpha, Kluyveromyces marxianus, Yarrowia lipolytica, Zygosaccharomyces bailii, or Saccharomyces cerevisiae are used, with the sole use of Corynebacterium glutamicum, particularly Corynebacterium glutamicum ATCC 13032, being especially preferred. The pH to be maintained during fermentation depends on the microorganism used. Microorganisms such as Corynebacterium glutamicum, Pseudomonas putida, or Escherichia coli are preferably cultivated at neutral pH values ​​(i.e., at a pH in the range of 6.0 to 8.0). Microorganisms such as Saccharomyces cerevisiae, on the other hand, are preferably cultivated in an acidic environment (i.e., at a pH in the range of 3.0 to 6.0).

[0082] In any case, the microorganism used for fermentation is preferably selected such that the ortho-isomer of aminobenzoic acid is formed during fermentation.

[0083] In a preferred embodiment of the invention, bacteria are used as microorganisms. Reference is made in particular to patent applications WO 2015 / 124686 Al and WO 2015 / 124687 Al, which describe a fermentation process usable according to the invention using bacteria (see, for example, WO 2015 / 124687 Al, (i) page 15, line 8 to page 16, line 30, (ii) Example 1 (page 29, lines 4 to 26), (iii) Example 3 (especially page 34, lines 10 to 18), (iv) Example 4 (especially page 55, lines 9 to 31)). In particular, bacteria are used that are capable of converting a fermentable carbon-containing compound into aminobenzoic acid in the presence of a suitable nitrogen source, without the aminobenzoic acid thus formed being immediately consumed again in intracellular biochemical processes, so that aminobenzoic acid accumulates in the cell and is ultimately released into the fermentation broth. transitions.

[0084] In another preferred embodiment of the invention, yeasts are used as microorganisms. Particular reference is made to international application WO 2017 / 102853 Al. Specifically, yeast cells are used that are capable of converting a fermentable carbon-containing compound into aminobenzoic acid in the presence of a suitable nitrogen source, without the aminobenzoic acid thus formed being immediately consumed again in intracellular biochemical processes, so that aminobenzoic acid accumulates in the cell and ultimately passes into the fermentation broth.

[0085] Suitable bacteria or yeast cells can be identified, for example, by screening for mutants that release aminobenzoic acid into the surrounding medium. However, the targeted modification of key enzymes using genetic engineering techniques is preferred. With conventional genetic engineering methods, gene expression and enzyme activity can be increased, decreased, or even completely suppressed at will. This results in recombinant strains. 2024PF30059 - Abroad

[0086] - 13 - In most cases, the fermentation broth present at the end of the fermentation is basic to neutral or at most slightly acidic (pH > 4.7), and the aminobenzoic acid is consequently present in dissolved form as its anion, aminobenzoate. In these cases, it is preferred to treat the fermentation broth with acid, in particular with hydrochloric acid, sulfuric acid, and / or phosphoric acid, to convert the anion into the electroneutral form. The acid is added, in particular, until the pH of the resulting mixture is in the range of 3.0 to 4.7, preferably in the range of 3.2 to 3.7 (especially for meta- and para-aminobenzoic acid), and most preferably in the range of 3.4 to 3.6 (especially for ortho-aminobenzoic acid).Then, aminobenzoic acid is predominantly or completely present in its electroneutral form and, due to its low water solubility, precipitates out except for a small fraction attributable to some residual solubility. This precipitate can then be easily separated from the supernatant fermentation broth, particularly by filtration or centrifugation. Filtration can be carried out at reduced pressure, ambient pressure, or increased pressure. Centrifugation can be performed using commercially available centrifuges. It is also possible to allow the suspension obtained from the acid treatment to stand until the precipitated aminobenzoic acid crystals settle out, and then to decant or siphon off the supernatant mother liquor.

[0087] However, if the fermentation broth is strongly acidic (pH < 3.0), a pH value within the aforementioned range is ensured by adding a base (preferably sodium hydroxide or lime). If, on the other hand, the pH value of the fermentation broth is in the range of 3.0 to 4.0, as can be the case when using yeast as the microorganism, in a preferred embodiment neither acid nor base is added, but the fermentation broth is processed directly without further pH adjustment. In this case, it can be expected that crystals of aminobenzoic acid will precipitate spontaneously and can be separated directly. The methods applicable to this separation are the same as those described above for acid treatment.

[0088] The separation of solid aminobenzoic acid present in aqueous solution and solid microorganisms, if necessary, is best achieved by centrifugation. This applies to all embodiments of the present invention in which such separation is required.

[0089] The aminobenzoic acid obtained by one of the methods described above can be further processed before decarboxylation. Washing with aqueous washing media, particularly water, is preferred. To avoid yield losses, the pH of the aqueous washing medium can be adjusted to the same value as after acid addition (or, in the case of yeasts, base addition); thus, in this embodiment, a dilute acid is used for washing instead of water. Suitable acids for this purpose are those mentioned above in connection with acid treatment. 2024PF30059 - Abroad

[0090] - 14 -

[0091] The decarboxylation of aminobenzoic acid can advantageously be carried out in the presence of aniline. Its autocatalytic effect in the decarboxylation is known and can eliminate the need for an inorganic catalyst (however, even without the addition of aniline at the start of the reaction, the use of an inorganic catalyst in the decarboxylation is not mandatory). The aminobenzoic acid is preferably added to the decarboxylation as a solution in aniline. When the reaction is carried out discontinuously, a mass fraction of aniline, based on the total mass of aniline and aminobenzoic acid, of 0.1% to 90%, preferably 1.0% to 70%, and particularly preferably 5.0% to 50%, is preferably adjusted before the start of the decarboxylation.When the reaction is carried out continuously, a mass fraction of aniline, based on the total mass of aniline and aminobenzoic acid, is preferably maintained during decarboxylation at a level of 0.1% to 90%, more preferably 1.0% to 70%, and particularly preferably 5.0% to 50%. Besides or in addition to aniline, other solvents or diluents can of course be used, in particular water, but also organic, polar, and / or protic solvents.

[0092] If an inorganic catalyst is used in the decarboxylation, in one embodiment it is such an inorganic catalyst that differs from the catalyst used for step (B) in at least one of the material properties (a) or (β). However, it is also possible to use such an inorganic catalyst in the decarboxylation that has material properties (a) and (β). The same catalyst as for step (B) can be used, but need not be. In any case, a heterogeneous metal oxide catalyst is suitable for step (B) which contains a mass fraction of Al₂O₃ of 40.0% to 100%, preferably 50.0% to 100%, and particularly preferably 60.0% to 100%, based on the total mass of the metal oxides, wherein the mass fraction of Al₂O₃ based on the total mass of the heterogeneous metal oxide catalyst is 25% to 100%.The catalyst preferably contains MgO in a mass fraction of 1.0% to 60.0% based on the total mass of the metal oxides. Preferably, the catalyst further contains SiC₂ in a mass fraction of 1.0% to 30.0% based on its total mass. The AβOs fraction of the inorganic heterogeneous metal oxide catalyst used in step (A)(1 I) preferably comprises Y-Al₂O₃ or p-AβOs and consists in particular of one of the two or a mixture of both.

[0093] Temperatures of 150 °C to 300 °C are particularly suitable for decarboxylation, preferably 160 °C to 280 °C, particularly preferably 180 °C to 240 °C, and most preferably 180 °C to 230 °C. The (absolute) reaction pressure can be 0.05 bar to 300 bar, preferably 1.0 bar to 100 bar, particularly preferably 1.0 bar to 60 bar, and most preferably 1.0 bar to 55 bar. In a preferred embodiment, a temperature gradient is maintained over steps (A)(11) and (B) such that step (A(11)) is carried out at temperatures of 180 °C to 2024PF30059 - Foreign

[0094] - 15 -

[0095] 230 °C and step (B) is carried out at temperatures of > 230 °C to 300 °C, in particular from 231 °C to 300 °C, preferably from 232 °C to 300 °C.

[0096] Generally, the initial reaction mixture should contain as little aminobenzoic acid as possible, since an excessive amount can impair the aminobenzanilide cleavage. It is therefore preferred that the proportion of aminobenzoic acid in the initial reaction mixture, based on its total mass, is a maximum of 5.0 wt%.

[0097] FIBRECY OF AMINOBENZANILIDE (STEP (B))

[0098] In step (B), the initial reaction mixture is converted with the elimination of carbon dioxide and the formation of aniline. Using 2-aminobenzanilide as an example, the overall reaction can be summarized as follows:

[0099] In a first step, 2-aminobenzanilide undergoes hydrolytic cleavage into aniline and ortho-aminobenzoic acid. Under the reaction conditions, the latter decarboxylates predominantly to completely in situ, forming carbon dioxide and further aniline molecules, resulting in a total of 2 moles of aniline and 1 mole of carbon dioxide per mole of 2-aminobenzanilide.

[0100] Preferably, the initial reaction mixture contains an aminobenzanilide mass fraction of 0.5% to 92% by mass, based on its total mass. The aminobenzanilide mass fraction depends on its origin. If the aminobenzanilide originates from a purely thermal decarboxylation of aminobenzoic acid (without the addition of an inorganic catalyst), the aminobenzanilide mass fraction is typically 1.0% to 6.0%, particularly 1.5% to 4.0%. If the aminobenzanilide originates from a catalyzed decarboxylation of aminobenzoic acid, the aminobenzanilide mass fraction is typically 0.5% to 5.0%, particularly 1.0% to 3.0%. If the aminobenzanilide originates from the bottom product of an aniline distillation (see the explanations below for details), the aminobenzanilide mass fraction is typically 15% to 30%. If aniline is distilled off before step (B), significantly higher values ​​are conceivable.

[0101] According to the invention, the catalyst used has the material properties (a) and (β) defined above. Preferably, the local absorption maximum lies in the IR spectrum. 2024PF30059 - Foreign

[0102] - 16 - adsorbed pyridines in the wavelength range of 1442 cm -1 up to 1448 cm -1 The concentration of Lewis acidic centers according to (β) is preferably from 3.0 .mol / g to 500 .mol / g, particularly preferably from 3.0 .mol / g to 200 .mol / g.

[0103] In one embodiment of the process according to the invention, the catalyst contains a main component in a mass fraction of 70% to 100% based on its total mass and is optionally doped with a minor component, wherein the minor component, if present, is in a mass fraction of 0.5% to 30% based on the total mass of the catalyst, wherein the main component is selected from a metal oxide of

[0104] Group III (Group 13 according to lUPAC nomenclature) or a metal oxide of the

[0105] Group IV (Group 4 according to IUPAC nomenclature), and wherein the optional minor component is selected from a metal oxide or semimetal oxide of Group IV (Group 14 according to IUPAC nomenclature), a metal oxide of Group IV (Group 4 according to IUPAC nomenclature), a metal oxide of Group VI (Group 6 according to IUPAC nomenclature), a metal oxide of a lanthanide, or a mixture thereof. The major component is preferably TiO₂ or ZrO₂. The minor component is preferably an oxide of silicon, zirconium, hafnium, tungsten, cerium, or a mixture of two or more thereof.

[0106] Step (B) is carried out according to the invention at temperatures of 210 °C to 350 °C, preferably 230 °C to 350 °C, particularly preferably 230 °C to 300 °C.

[0107] As regards the pressure, step (B) is preferably carried out at a pressure in a gas space above the reacting initial reaction mixture of 1.0 bar to 200 bar, preferably 5.0 bar to 100 bar.

[0108] Step (B) is preferably carried out for a period (reaction time in batch processes or residence time in continuous processes) of 5 min to 360 min, preferably 15 min to 210 min. In batch processes, the period for step (B) corresponds to the reaction time. In continuous processes, the period for step (B) corresponds to the residence time, whereby the specified value ranges apply particularly to plug-flow tubular reactors; the value ranges may differ for continuously flowing stirred tank reactors.

[0109] The following describes various possible embodiments of the preferred embodiment of the invention, in which, in step (B), such aminobenzanilide is converted to carbon dioxide and aniline, which is obtained as a byproduct of a decarboxylation (step (A)(II)) of aminobenzoic acid. 2024PF30059 - Abroad

[0110] - 17 - In one variant of this embodiment, step (A)(1 I) and step (B) are carried out in different reactors. Before carrying out step (B), water can be added and, if necessary, the mixture can be freed from any solids present, in particular by filtration. In order to keep the volume flow rate that must be supplied to step (B) as low as possible, it is conceivable to distill off a portion of the aniline before adding the water.

[0111] There are several ways to carry out steps (A)(II) and (B). For example, in a continuous reaction, a further reactor (post-reactor for aminobenzanilide hydrolysis) can be added directly downstream of the decarboxylation reactor. In this post-reactor, the crude aniline obtained from the decarboxylation, containing aminobenzanilide, is reacted with the latter. Alternatively, in a batch reaction, the crude aniline from the decarboxylation reactor can be transferred to a second reactor for aminobenzanilide hydrolysis. It is also possible (if necessary, in combination with the previously described method) to incorporate step (B) into the purification of the aniline formed. In general, the crude aniline from the decarboxylation will need to be purified by distillation before further use.Such purification preferably comprises a first distillation to separate low-boiling substances such as water or other solvents or diluents used in the decarboxylation, as well as low-boiling organic by-products. In this first distillation, the aniline freed from low-boiling substances is obtained as the bottoms product. Since the aminobenzanilides have significantly higher boiling points than aniline, they are also present in this bottoms product. In a preferred embodiment of the invention, this bottoms product is then fed to step (B) before it is optionally subjected to a second distillation, in which the aniline is obtained as the distillate.

[0112] In another embodiment of the preferred model, steps (A)(l I ) and (B) are carried out continuously in a common reaction apparatus. The reaction apparatus is continuously supplied with aminobenzoic acid at one inlet point and with water at this inlet point and / or at another inlet point different from the aminobenzoic acid inlet point. Aniline is continuously withdrawn at an outlet point.In this process, a reacting mixture is formed in the reaction apparatus. This mixture initially flows through a first reaction zone arranged in the reaction apparatus, optionally filled with the catalyst for step (A)(II). After reaching a mass fraction of aminobenzanilide in the range of 0.5% to 6.0%, preferably 1.0% to 4.0%, and a mass ratio of aminobenzanilide to water of at most 11.7:1, the mixture flows through a second reaction zone arranged in the reaction apparatus, filled with the catalyst for step (B), at the end of which the outlet is located. Carbon dioxide produced during the reaction can be discharged at 2024PF30059 - Abroad.

[0113] - 18 - the exit point for aniline or at a further exit point different from this exit point continuously.

[0114] The first and second reaction zones can be arranged in two reactors connected in series, which together form the reaction apparatus. Alternatively, the first and second reaction zones can be two reaction chambers arranged in series within a reactor common to both step (A)(l I ) and step (B), in which case the reactor is identical to the reaction apparatus.

[0115] Steps (A)(11) and (B) can of course also be carried out in a batch reaction within a single reaction apparatus (in a single reactor). In this case, step (B) begins with the addition of the catalyst for step (B) and / or with raising the temperature to the value specified for step (B) (see the explanations above regarding the temperature gradient in steps (A)(11) and (B)).

[0116] 2024PF30059 - Abroad

[0117] - 19 -

[0118] Starting materials:

[0119] Anthranilic acid (AS, petrochemical): C7H7NO2, purity > 98%, Acros Organics

[0120] Aniline (ANL): C6H7N, purity > 99.5%, Sigma-Aldrich.

[0121] 2-Aminobenzanilide (AMD): C13H12N2O, purity 95%, but GmbH,

[0122] VE water: deionized.

[0123] Catalysts:

[0124] • Rural MG30 (spinel-like structure, mass ratio MgO : Al2O3 30 : 70), Sasol.

[0125] • AI2O3 (AI 4126 E), BASF.

[0126] • NbzOs hydrate, CBMM.

[0127] • ZnO (>99%), Sigma-Aldrich.

[0128] • ZrO2(tetragonal, SZ61152), SAINT-GOBAIN.

[0129] • W-doped ZrO2 (monoclinic, SZ31292), SAINT-GOBAIN.

[0130] • Rare-earth-doped ZrÜ2 (XZO1291 / 16), Luxfer.

[0131] • W-doped ZrO2(XZ01903 / 10), Luxfer.

[0132] • SiraloxlO (mass ratio SiO2:Al2O3 10:90), Sasol.

[0133] • 4% SiÜ2 / ÜO2 (Hombikat M411), Sachtleben Chemie GmbH (now VENATOR).

[0134] • TiO2(Anatase, ST61120), SAINT-GOBAIN.

[0135] HPLC

[0136] For HPLC analysis, an Agilent system with UV detection (DAD, measured at 254 nm) was used. An Agilent column (Eclipse XDB-C18; 5 pm; 4.6 × 150 mm) was used for separation. A mixture of MeOH and buffer was used as the mobile phase (MeOH : buffer volume ratio = 40 : 60, buffer: 0.7 mL of 85% pA H3PO4, diluted to a final volume of 1 L with HPLC water, with pH adjusted to 3.0 using sodium hydroxide solution before final filling). The flow rate was 0.7 mL / min. The column oven was heated to 40 °C. The injection volume was 1 pL. The retention times of the individual components aniline (ANL), anthranilic acid (AS), and 2-aminobenzanilide (AMD) were: ANL = 3.4 min; AA = 5.7 min; AMD = 17.7 min. 2024PF30059 - Foreign

[0137] - 20 -

[0138] The peak areas are converted into area percent. The quantification of the individual components in mass percent, based on the reaction mixture, was made possible by a previously established calibration using pure substances. In addition to the mass composition, the conversion of 2-aminobenzanilide, the yield of aniline formed, the selectivity of aniline formation, and the selectivity for the formation of anthranilic acid are determined based on these values. 2 to

[0139] The cleavage of 2-aminobenzanilide to aniline / anthranilic acid is carried out in a stainless steel reactor, which is filled with 0.03 g of 2-aminobenzanilide, 2.0 g of aniline, powdered catalyst (amounts see Table 25), and deionized water (amounts see Tables 2 to 5). The reactor is then sealed and purged with argon. The reaction mixture is stirred for a defined reaction time at a defined temperature and 360 rpm. During this time, pressure builds up due to the release of CO₂ (product of anthranilic acid decarboxylation). The reaction mixture is then cooled in an ice bath, the pressure is released, and the mixture is diluted with 4.0 g of methanol. The diluted mixture is filtered and characterized by HPLC analysis. on a from ANL

[0140] The crude product of a thermal decarboxylation (without the addition of a catalyst) of anthranilic acid at 225 °C for 1 h was simulated using commercially available chemicals. The experimental decarboxylation was carried out according to general procedure 1 from WO 2022 / 253890 Al (page 16, lines 5 to 15). According to the HPLC results, this crude product contained 93 wt% aniline, 3.3 wt% anthranilic acid, and 3.7 wt% 2-aminobenzanilide.

[0141] implementation

[0142] Approximately 2 g of a mixture of the aforementioned composition are added to 0.3 g of catalyst (11.2 wt%, see Table 6) and 0.38 g of H₂O (15.9 wt%). After reducing the pressure to 100 mbar and purging the reactor with argon, the reaction mixture is heated to 245 °C and stirred for 1.5 h or 3 h (360 rpm). The reaction mixture is then... 2024PF30059 - Abroad

[0143] - 21 - cooled in an ice bath, pressure released, and the mixture diluted with approximately 4.0 g of methanol. This diluted mixture is characterized by HPLC analysis. the thermal

[0144] Using a Vigreux column, the product of the thermal decarboxylation of anthranilic acid, synthesized in a continuous reactor, was distilled to extract aniline. The total mixture was approximately 811.63 g / 800 mL. Under 250 mbar vacuum, boiling began at a bottom temperature of 90 °C. The temperature then rose to 140 °C and remained constant. After 3 h of distillation, approximately 626.12 g / 600 mL of aniline and 3.91 g of water were collected. The remaining mass in the bottom was 172.53 g / 200 mL, which, according to HPLC analysis, contained 81.9 wt% aniline, 4.0 wt% anthranilic acid, and 14.1 wt% anthranilic acid.

[0145] Procedure (Table 7)

[0146] To test the AMD cleavage process, approximately 2 g of this mixture are added to 0.3 g of catalyst (either 4% SiO₂ / TiO₂, WO₃ / ZrC₆, t-ZrO₂, SiraloxlO₂, or Y-Al₂O₃) and 0.38 g of H₂O, corresponding to 13 wt% catalyst and 16 wt% H₂O. The reaction is carried out at 245 °C for 1.5 or 3 h in finger autoclaves. The reaction mixture is then cooled in an ice bath, the pressure is released, and the mixture is diluted with approximately 4.0 g of methanol. This diluted mixture is characterized by HPLC analysis.

[0147] Measurement method: Lewis acidic egg (q) and (ß)) using IR-I iie with pyridine as probe molecule

[0148] Introduction

[0149] Pyridine IR spectroscopy is a method for identifying the type and strength of acidic / basic sites in a solid. Using pyridine as a probe molecule, Brensted and Lewis acids can be easily distinguished. The acid and base strength of metal oxides can be analyzed based on the signal shift values ​​of adsorbed probe molecules, as described in [1], [2], and [3]. As described in [4], the quantity and type of acidic centers can be determined by Fourier transform infrared spectroscopy. 2024PF30059 - Abroad

[0150] - 22 -

[0151] Literature:

[0152] [1] M. Tamura, et al. "Comprehensive IR study on acid / base properties of metal oxides." Applied Catalysis A: General, 433 (2012): 135-145.

[0153] [2] M. Barreau, et al. "FT-IR spectroscopy study of HNCO adsorption and hydrolysis over oxidebased samples dedicated to deNOx processes." Applied Catalysis A: General, 552 (2018): 147-153.

[0154] [3] M. Shamzhy, et al. "Quantification of Lewis acid sites in 3D and 2D TS-1 zeolites: FTIR spectroscopic study." Catalysis Today, 345 (2020): 80-87.

[0155] [4] C. Mebrahtu, et al. "Unraveling the structure-activity relationships of Cu / H-BEA bifunctional catalyst for selective synthesis of dimethoxymethane by non-oxidative dehydrogenation of methanol." Applied Catalysis B: Environmental, 287 (2021): 119964.

[0156] implementation

[0157] The catalysts to be investigated are analyzed using Fourier transform infrared spectroscopy (FTIR) with a Vertex 70 FT-IR spectrometer as follows:

[0158] For this purpose, the samples are first pressed into a self-supporting thin wafer (20 mg sample and 80 mg KBr). A background spectrum of the stainless steel IR cell with CaFz windows is first recorded by heating the empty cell to 80 °C under vacuum (0.004 mbar). The cell is then cooled to room temperature, the prepared wafer is mounted, and then held at 250 °C under vacuum (0.004 mbar) for 1 h. Afterward, the cell is cooled to 80 °C for the sample measurement. Spectra from 8000 to 850 cm⁻¹ are obtained. 1 with a resolution of 2 cm 1 A second background spectrum is recorded at 80 °C while the sample is inside the cell.

[0159] The spectra are then recorded during pyridine adsorption as follows: First, pyridine adsorption is carried out at 80 °C for 2 min in pyridine vapor (approx. 4.2 mbar) and balanced for 30 min. Next, desorption of weakly bound pyridine is initiated at 200 °C for 30 min under 0.004 mbar vacuum. Afterward, the temperature is lowered to 80 °C, and the spectra are determined by subtracting the background spectrum (degassed samples prior to pyridine adsorption) from the measured sample spectra. Pyridine is the most suitable probe molecule for quantifying the number of acid sites on the metal oxides because it is readily absorbed by Brensted-type (~1545 cm⁻¹) molecules. 1 ) and Lewis acid spots (~1445 cm' 1 ) adsorbs and produces well-resolved and distinct signals in the spectra. The concentration of Lewis acid sites C w (pmol-g -1 ) is calculated based on the Lambert-Beer Act: 2024PF30059 - Abroad

[0160] - 23 -

[0161] AS

[0162] Cw ~ w where A (peak area in cm² ), S (m²) 2 ), e (m 2 -mol -1 ) and W (kg) represent the IR absorption, the area of ​​the sample disk, the integrated molar extinction coefficient, and the mass of the sample. According to the literature, the integrated molar extinction coefficients for Lewis and Brensted acid sites of metal oxides do not depend significantly on the type of oxide. Therefore, the value for e (1440 cm) 4 ) of 1.73 cm-pmol 1 taken from Tamura et al. [1]. The concentrations of Lewis acid sites determined here are summarized in Table 1.

[0163] The experiments are summarized in the tables below. The following abbreviations are used: Cat. = catalyst

[0164] ANL = Aniline

[0165] AS = Anthranilic acid

[0166] AMD = 2-aminobenzenanilide tetr. = Tetragonal MK = Monocline

[0167]

[0168] 2024PF30059 - Abroad

[0169] - 25 -

[0170] Explanations for Table 1:

[0171] [a] The positions of the local absorption maxima determined by the method described above (Ä,Max; material property (a)) and the concentration of Lewis acidic centers (Cw; material property (β)) are given. This means that no absorption was detected using the described method. Catalysts that meet the requirements of the invention are highlighted in bold.

[0172] [b] Two local absorption maxima were measured, one within and one outside the wavelength range essential to the invention. Although the presence of an additional local absorption maximum outside the wavelength range essential to the invention is not preferred, it does not preclude the use of a catalyst in the process according to the invention.

[0173] [c] Sum of ZrO2 and HfO2, where HfO2 makes up only one trace.

[0174] Table 2: Amide cleavage to aniline / anthranilic acid. Reaction temperature T = 235 °C;

[0175] Reaction time tR = 3 h. Various catalysts. See the explanations in Table 7. 2024PF30059 - Abroad

[0176] - 26 -

[0177] Table 3: Amide cleavage to aniline / anthranilic acid. Reaction temperature T = 235 °C;

[0178] Different reaction times t. See the explanations after Table 7.

[0179] Table 4: Amide cleavage to aniline / anthranilic acid. Reaction temperature T = 245 °C;

[0180] Varying catalyst amounts, water contents, and reaction times. See the explanations after Table 7.

[0181] Table 5: Amide cleavage to aniline / anthranilic acid. Reaction temperature T = 225 °C;

[0182] Various catalysts. See the explanations after Table 7. 2024PF30059 - Abroad

[0183] - TI -

[0184] Table 6: AMD cleavage process applied to a mixture of ANL, AS, and AMD (representing the product of the thermal decarboxylation of AS). Reaction temperature T = 245 °C. See the explanations following Table 7. 2024PF30059 - Abroad

[0185] - 28 -

[0186] Ta at le 7: AMD cleavage of the distillation residue of the thermal decarboxylation with ANL, AS and AMD. Reaction temperature T = 245 °C. See the explanations on the next page. 2024PF30059 - Abroad

[0187] - 29 -

[0188] Explanations for Tables 2 to 7:

[0189] (V) Comparative example;

[0190] [a] Mass fraction in %, based on the total mass of AMD, ANL, AS, H2O and catalyst; catalyst is used as a powder (slurry);

[0191] [b] Mass fraction in % in the reactant mixture, based on the total mass of AMD, ANL, AS and H2O;

[0192] [c] Mass fraction in % in the product mixture, based on the total mass of AS, ANL and AMD;

[0193] [d] Chemical conversion of 2-aminobenzanilide (AMD) in %;

[0194] [e] Chemical conversion of anthranilic acid (AA) in %.

[0195] The performance of the best catalysts for the AMD split decreases in the following order: 4%SiO2 / TiO2(K10; XAMD = 98.7) > ZrO2(K5; X A MD = 98.1) > WO3 / ZrO2 (K8; XAMD = 97.9) > SiraloxlO (K9; XAMD = 89.6). Table 1 shows that 4%SiO2 / TiO2 exhibits the highest AMD cleavage activity among the tested catalysts, with the highest concentration of acidic Lewis sites and the FTIR peak at a low wavenumber. The higher catalytic AMD cleavage activity of SiraloxlO compared to yA^Os can be explained by the higher concentration of acidic Lewis sites on SiraloxlO, also at a similar FTIR peak wavenumber. In summary, high concentrations of acidic Lewis sites with low acid strength (red shifted at 1445 cm⁻¹) 1 ) are advantageous for AMD cleavage, as observed in the case of 4%SiO2 / TiO2 catalysts.

[0196] TiO2 (ST61120, K11) is somewhat less efficient in the aminobenzanilide cleavage than 4% SiO2 / TiO2 (K10), but nevertheless exhibits very considerable activity, in stark contrast to the results shown in WO 2022 / 253890 Al for the same catalyst TiÜ2 (ST61120) (see the discussion above in this document; there, an increase in the aminobenzanilide content was even observed). In the process according to WO 2022 / 253890 Al, the TiO2 catalyst is used in a comparative experiment. The most efficient decarboxylation catalyst according to WO 2022 / 253890 Al, Pural®MG30 (catalyst Kl used for comparison in the present invention), shows a significantly worse result in the aminobenzanilide cleavage than K11; see Table 2 above. These results demonstrate that different factors play a role in the cleavage of aminobenzanilide than in the (preferably selective) decarboxylation of aminobenzoic acid described in WO 2022 / 253890 Al.

Claims

2024PF30059 - Abroad - 30 - 1. Method for the cleavage of aminobenzanilide to aniline, comprising the steps of: (A) Providing a starting reaction mixture containing aminobenzanilide and water, wherein the aminobenzanilide and water are present in the starting reaction mixture in a mass ratio of not more than 11.7 : 1; and (B) Reacting the initial reaction mixture with release of carbon dioxide and formation of aniline in the presence of a catalyst at a temperature of 210 °C to 350 °C, wherein the catalyst comprises a metal oxide having the following material properties: (oc) a local absorption maximum in an IR spectrum at the pyridine adsorbed by the metal oxide in a wavelength range of 1435 cm 1 up to 1453 cm -1 and (β) a concentration of Lewis acidic centers of at least 3.0 mol / g.

2. Method according to claim 1, wherein for the catalyst used in step (B) the local absorption maximum in the IR spectrum of adsorbed pyridine is in the wavelength range of 1442 cm" 1 up to 1448 cm" 1 lies and the concentration of Lewis acidic centers ranges from 3.0 .mol / g to 500 .mol / g.

3. A method according to any of the preceding claims, wherein the catalyst used in step (B) contains a major component in a mass fraction of 70% to 100% based on its total mass and is optionally doped with a minor component, wherein the minor component, if present, is present in a mass fraction of 0.5% to 30% based on the total mass of the catalyst, wherein the major component is selected from a metal oxide of group III or a metal oxide of group IV, and wherein the minor component, if present, is selected from a metal oxide or semimetal oxide of group IV, a metal oxide of group IV, a metal oxide of group VI, a metal oxide of a lanthanide, or a mixture thereof.

4. The method of claim 3, wherein the main component is TiOz or ZrOz. 2024PF30059 - Abroad - 31 - 5. The method of claim 3 or 4, wherein the accessory component is an oxide of silicon, zirconium, hafnium, tungsten, cerium or a mixture of two or more thereof.

6. Method according to any one of claims 1 to 5, wherein step (B) is carried out at a temperature of 230 °C to 350 °C.

7. A method according to any one of claims 1 to 6, wherein step (A) comprises: (A)(1) Providing aminobenzoic acid, and (A)(ll) Reaction of the aminobenzoic acid with release of carbon dioxide to form a mixture containing aniline and aminobenzanilide.

8. Method according to claim 7, wherein step (A)(ll) is carried out at a temperature of 150 °C to 300 °C.

9. Method according to claim 8, wherein step (A)(ll) is carried out at a temperature of 180 °C to 230 °C and step (B) is carried out at a temperature of > 230 °C to 300 °C.

10. Method according to any one of claims 7 to 9, wherein step (A)(l I) is carried out without the addition of an inorganic catalyst.

11. Method according to any one of claims 7 to 9, wherein step (A)(ll) is carried out in the presence of an inorganic catalyst which differs in at least one of the material properties (oc) or (ß) from the catalyst used for step (B).

12. Method according to any one of claims 7 to 9, wherein step (A)(l I) is carried out in the presence of an inorganic catalyst having the material properties (oc) and (ß).

13. The method of claim 12, wherein the inorganic catalyst used in step (A)(ll) is different from the catalyst used in step (B).

14. Method according to any one of claims 7 to 13, wherein step (A)(1 I) and step (B) are carried out in different reactors. 2024PF30059 - Abroad - 32 - 15. A method according to any one of claims 7 to 13, wherein step (A)(1) and step (B) are carried out in a common reaction apparatus, which is continuously supplied with aminobenzoic acid at an inlet point and with water at this inlet point and / or at a further inlet point different from the inlet point for aminobenzoic acid, and from which aniline is continuously withdrawn at an outlet point, wherein a reacting mixture is formed in the reaction apparatus, which first flows through a first reaction zone arranged in the reaction apparatus, optionally filled with the catalyst for step (A)(12), and which, after reaching a mass fraction of aminobenzanilide in the range of 0.5% to 6.0% based on the total mass of the reacting mixture and a mass ratio of aminobenzanilide to water of at most 11.7:1, flows through a second reaction zone arranged in the reaction apparatus.The reaction zone filled with the catalyst for step (B) flows through, and the exit point is located at the end of this zone.

16. A method according to any of the preceding claims, wherein the initial reaction mixture contains aminobenzoic acid in a mass fraction of 0% to 5.0%, based on its total mass.

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