A method for preparing aromatic methylamine

Abstract

The present invention belongs to the field of chemical engineering and discloses a method for preparing aromatic methylamines, comprising: a first step of mixing an aromatic carboxylic acid, ammonia, and a carrier gas, and preheating the mixture to a gaseous state to obtain a mixed gas; and a second step of subjecting the mixed gas to a gas-solid phase catalytic reaction at a reaction temperature of 380°C to 560°C and a reaction pressure of 0.05 MPa to 0.25 MPa to obtain the aromatic methylamines. In the aromatic methylamine preparation process of the present invention, the aromatic carboxylic acid undergoes a gas-phase reaction, enabling continuous preparation of the aromatic methylamines and improving production efficiency. By controlling the reaction temperature and pressure range, the aromatic methylamines can be directly prepared from the aromatic carboxylic acid, reducing the number of reaction control steps. By selecting catalysts doped with multiple elements, their synergistic effects can be exploited, shortening the lifetime of transition intermediates and enabling rapid conversion of the aromatic carboxylic acid to the aromatic methylamines.

Description

Technical Field

[0001] The present invention generally relates to the field of chemical technology. More specifically, the present invention relates to a method for preparing aromatic methylamines. Background Art

[0002] Aromatic amine compounds are important organic raw materials and are widely used in the production of dyes, medicines, agricultural chemicals, additives, surfactants, textile auxiliaries, chelating agents, polymers, flame retardants, etc.

[0003] Aromatic amines can be prepared directly from aromatic hydrocarbons, by hydrogenation of nitrated aromatic hydrocarbons, or by hydrogenation of aromatic amides. The vast majority of aromatic amines are prepared by the reduction of aromatic nitro compounds. Numerous methods exist for reducing nitro groups to amino groups. Currently, the main industrially used methods include: metal reduction in acidic, neutral, or alkaline systems; chemical reduction; catalytic hydrogenation; and electrochemical reduction. Catalytic hydrogenation uses precious metals such as Pd, Pt, and Ni, and their alloys, as catalysts to reduce nitro groups to amino groups under specific temperature and pressure.

[0004] The preparation of aromatic amines in the prior art has problems such as low production efficiency and raw material conversion efficiency, and complicated steps. There is still a need for a method that can directly prepare aromatic amines through continuous reaction to improve production efficiency and raw material conversion rate. Summary of the Invention

[0005] In order to at least solve one or more of the technical problems mentioned above, the present invention provides a method for preparing aromatic methylamine, comprising: a first step of mixing an aromatic carboxylic acid, ammonia, and a carrier gas, and preheating the mixture to a gaseous state to obtain a mixed gas; a second step of subjecting the mixed gas to a gas-solid phase catalytic reaction at a reaction temperature of 380-560° C. and a reaction pressure of 0.05-0.25 MPa to obtain the aromatic methylamine.

[0006] According to one embodiment of the present invention, in the mixed gas, ammonia is in excess relative to the aromatic carboxylic acid.

[0007] According to one embodiment of the present invention, in the mixed gas, the molar ratio of the aromatic carboxylic acid to the ammonia is 1:15 to 1:30.

[0008] According to one embodiment of the present invention, in the mixed gas, the molar ratio of the aromatic carboxylic acid to the ammonia is 1:20.

[0009] According to one embodiment of the present invention, in the mixed gas, ammonia accounts for 10-100% of the total volume of ammonia and carrier gas.

[0010] According to one embodiment of the present invention, in the mixed gas, ammonia accounts for 20-60% of the total volume of ammonia and carrier gas.

[0011] According to one embodiment of the present invention, the aromatic carboxylic acid is selected from: C (2+4n) H (2n+4-m) (COOH) m , where n is selected from 1, 2 or 3; when n=1, m=1, 2 or 3; when n=2, m=1 or 2; when n=3, m=1.

[0012] According to one embodiment of the present invention, the aromatic carboxylic acid is selected from the group consisting of benzoic acid, isophthalic acid, terephthalic acid, 1,8-naphthalene dicarboxylic acid, 1-naphthalene dicarboxylic acid, 2-naphthalene dicarboxylic acid, 9-anthracene dicarboxylic acid, 3-phenanthracene dicarboxylic acid, 1-anthracene dicarboxylic acid, 2-anthracene dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 2-phenanthracene dicarboxylic acid, and trimellitic acid.

[0013] According to one embodiment of the present invention, the carrier gas is selected from at least one of nitrogen, carbon dioxide, helium, argon, hydrogen, and ammonia. Preferably, the carrier gas is selected from at least one of hydrogen and ammonia. More preferably, the carrier gas is selected from ammonia.

[0014] According to one embodiment of the present invention, the preheating temperature of the mixed gas is 200° C. to 500° C. Preferably, the preheating temperature of the mixed gas is 300° C. or 350° C.

[0015] According to one embodiment of the present invention, the reaction temperature of the gas-solid phase catalytic reaction is 400-500° C., the reaction pressure is 0.07-0.10 MPa, and the reaction time is 10-60 s.

[0016] According to one embodiment of the present invention, the catalyst for the gas-solid phase catalytic reaction is a supported catalyst, wherein the active components of the supported catalyst are selected from at least three elements selected from transition metals, alkali metals, alkaline earth metals, and noble metals. Preferably, the active components of the supported catalyst are selected from at least three elements selected from Au, P, Ti, Mo, Ru, Ni, Pt, Pd, Rh, Ag, and Co. More preferably, the active components of the supported catalyst include at least Au and Ag.

[0017] According to one embodiment of the present invention, the active component accounts for 1-10% by mass of the supported catalyst.

[0018] According to one embodiment of the present invention, the mass percentage of the active component to the supported catalyst is 5-8%.

[0019] According to one embodiment of the present invention, the carrier of the supported catalyst is selected from SiO2, Al2O3, and TiO2.

[0020] According to one embodiment of the present invention, the carrier of the supported catalyst is Al2O3.

[0021] According to one embodiment of the present invention, the active components of the supported catalyst include the following elements: Ag: 1 part by weight; P: 0~0.5 part by weight; Ti: 0~0.3 part by weight; Mo: 0~0.3 part by weight; Ru: 0~0.4 part by weight; Ni: 0~0.5 part by weight; Pt: 0~0.2 part by weight; Pd: 0~0.3 part by weight; Rh: 0~0.3 part by weight; Au: 0~0.5 part by weight; Co: 0~0.3 part by weight.

[0022] In the preparation process of aromatic methylamine of the present invention, a gas phase reaction is carried out in the presence of ammonia and a catalyst, starting from an aromatic carboxylic acid to directly and continuously generate aromatic methylamine and by-products. In the present invention, a gaseous aromatic carboxylic acid is formed by preheating, and a mixed gas is formed with ammonia and a carrier gas, thereby achieving a continuous gas phase reaction, thereby improving production efficiency. By controlling the reaction temperature and pressure range, aromatic methylamine can be directly prepared from aromatic carboxylic acid, reducing the number of reaction control steps. By selecting the reaction temperature and pressure, transition state intermediates such as aromatic amides can be quickly converted into aromatic methylamines after a short period of existence. By selecting a catalyst doped with multiple elements, their synergistic effect can be exerted, shortening the duration of the transition state intermediates, thereby improving reaction efficiency and achieving rapid conversion from aromatic carboxylic acids to aromatic methylamines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an illustrative and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0024] Figure 1 A schematic diagram of the steps of a method for preparing aromatic methylamines is shown;

[0025] Figure 2 A block diagram of a reaction system suitable for an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0027] It should be understood that the terms "include" and "comprising" used in the description and claims of the present invention indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0028] It should also be understood that the terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the present invention. As used in the specification and claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should further be understood that the term "and / or" as used in the specification and claims refers to any and all possible combinations of one or more of the associated listed items, including and including these combinations.

[0029] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Figure 1 A schematic diagram of the steps of a method for preparing aromatic methylamines is shown.

[0031] like Figure 1 As shown, the present invention provides a method for preparing aromatic methylamine, comprising: a first step S1, mixing an aromatic carboxylic acid, ammonia and a carrier gas, and preheating them to a gaseous state to obtain a mixed gas; a second step S2, subjecting the mixed gas to a gas-solid phase catalytic reaction at a reaction temperature of 380-560°C and a reaction pressure of 0.05-0.25 MPa to obtain aromatic methylamine.

[0032] In the preparation process of the aromatic methylamine of the present invention, a gas phase reaction is carried out in the presence of ammonia and a catalyst, starting from an aromatic carboxylic acid. The reaction can be carried out continuously to directly generate the aromatic methylamine and by-products.

[0033] The reactor suitable for the present invention includes at least one of a fixed bed, a fluidized bed, and an ebullating bed, preferably a fluidized bed or a fixed bed. The reactor is preloaded with a solid-phase catalyst. The aromatic carboxylic acid is preheated to a gaseous state and then transported along with ammonia by a carrier gas into the reactor for a gas-solid phase catalytic reaction.

[0034] In the present invention, a gaseous aromatic carboxylic acid is preheated to form a mixed gas with ammonia and a carrier gas, enabling a continuous gas-phase reaction and improving production efficiency. By controlling the reaction temperature and pressure range, aromatic methylamines can be directly prepared from aromatic carboxylic acids, reducing reaction control steps and improving reaction efficiency.

[0035] In an embodiment of the present invention, the aromatic carboxylic acid is selected from: C (2+4n) H (2n+4-m)(COOH) m , where n is selected from 1, 2 or 3; when n=1, m=1, 2 or 3; when n=2, m=1 or 2; when n=3, m=1.

[0036] Preferably, the aromatic carboxylic acid is selected from the group consisting of benzoic acid, isophthalic acid, terephthalic acid, 1,8-naphthalene dicarboxylic acid, 1-naphthalene dicarboxylic acid, 2-naphthalene dicarboxylic acid, 9-anthracene dicarboxylic acid, 3-phenanthracene dicarboxylic acid, 1-anthracene dicarboxylic acid, 2-anthracene dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 2-phenanthracene dicarboxylic acid, and trimellitic acid.

[0037] In the present invention, by preferably selecting the aromatic carboxylic acid shown in the above expression and the aromatic carboxylic acids listed above, rapid preheating and gasification can be achieved, with lower temperature requirements and stronger fluidity, which is suitable for large-flow production in industrial scenarios.

[0038] According to one embodiment of the present invention, the carrier gas is selected from at least one of nitrogen, carbon dioxide, helium, argon, hydrogen, and ammonia. Preferably, the carrier gas is selected from at least one of hydrogen and ammonia. More preferably, the carrier gas is selected from ammonia.

[0039] In the present invention, the carrier gas may be nitrogen, carbon dioxide, helium, or argon, which are relatively inert to the hydrogenation reaction, or hydrogen and / or ammonia, which have a promoting effect on the hydrogenation reaction. When ammonia is used as the carrier gas, it can appropriately release hydrogen at the temperature and pressure specified in the present invention, thereby promoting the forward progress of the catalytic hydrogenation reaction.

[0040] According to one embodiment of the present invention, in the mixed gas, ammonia is in excess relative to the aromatic carboxylic acid. That is, the molar amount of ammonia is greater than the molar amount of the aromatic carboxylic acid. Excess ammonia can promote the catalytic hydrogenation reaction of the aromatic carboxylic acid and improve the conversion rate of the aromatic carboxylic acid. Preferably, in the mixed gas, the molar ratio of the aromatic carboxylic acid to the ammonia is 1:15~1:30. More preferably, the molar ratio of the aromatic carboxylic acid to the ammonia is 1:20. The molar amount of ammonia is 15 to 30 times that of the aromatic carboxylic acid. On the one hand, the conversion rate of the aromatic carboxylic acid can be improved. On the other hand, the excess ammonia can provide hydrogen during the reaction to promote the catalytic hydrogenation reaction.

[0041] According to one embodiment of the present invention, in the mixed gas, ammonia accounts for 10 to 100% of the total volume of ammonia and carrier gas. Preferably, ammonia accounts for 20 to 60% of the total volume of ammonia and carrier gas. The total volume of ammonia and carrier gas is the sum of the volume of ammonia and the volume of carrier gas. When the carrier gas is a gas other than ammonia, ammonia accounts for at least 10% to ensure that the ammonia concentration is not lower than the reaction concentration between it and the aromatic carboxylic acid. When the carrier gas is ammonia, ammonia accounts for 100%. Preferably, when the carrier gas is not ammonia, ammonia accounts for 20 to 60% of the total volume of ammonia and carrier gas, so that the concentration of ammonia is optimal, and ammonia for reacting with aromatic carboxylic acid and ammonia for providing hydrogen can be provided simultaneously.

[0042] According to one embodiment of the present invention, the preheating temperature of the mixed gas is 200°C to 500°C. Preferably, the preheating temperature of the mixed gas is 300°C or 350°C. In the present invention, the minimum preheating temperature is set differently depending on the type of aromatic carboxylic acid. The maximum preheating temperature can be set slightly lower than the reaction temperature of the gas-solid phase catalytic reaction, which can reduce premature decomposition of the aromatic carboxylic acid during the gasification process.

[0043] According to one embodiment of the present invention, the reaction temperature of the gas-solid phase catalytic reaction is 400-500°C, the reaction pressure is 0.07-0.10 MPa, and the reaction time is 10-60 seconds. The reaction time is adjusted according to different reaction temperatures and reaction pressures, as well as the catalytic capacity of the catalyst. Under the above-mentioned reaction temperature, reaction pressure, and other conditions, the aromatic carboxylic acid and ammonia form aromatic amides or transition intermediates thereof, which are hydrogenated to form aromatic methylamines under the catalytic action of the gas-solid phase catalyst. Due to the selection of the above-mentioned reaction temperature and pressure, the aromatic amides or other transition intermediates are directly converted into aromatic methylamines after a short period of existence.

[0044] According to one embodiment of the present invention, the catalyst for the gas-solid phase catalytic reaction is a supported catalyst, wherein the active components of the supported catalyst are selected from at least three elements selected from transition metals, alkali metals, alkaline earth metals, and precious metals. Preferably, the active components of the supported catalyst are selected from at least three elements selected from Au (gold), P (phosphorus), Ti (titanium), Mo (molybdenum), Ru (ruthenium), Ni (nickel), Pt (platinum), Pd (palladium), Rh (rhodium), Ag (silver), and Co (cobalt). More preferably, the active components of the supported catalyst include at least Au (gold) and Ag (silver).

[0045] Transition metals mainly refer to all elements of groups IIIB, IVB, VB, VIB, VIIB, as well as VIII, IIB, and IIB.

[0046] Precious metals mainly refer to gold, silver and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium and platinum).

[0047] Alkaline earth metals mainly refer to beryllium, magnesium, calcium, strontium, barium and radium.

[0048] Alkali metals mainly refer to lithium, sodium, potassium, rubidium, cesium, and francium.

[0049] The active component can be randomly selected from the above metals. Preferably, the active component must contain Ag and / or Au.

[0050] In the present invention, by selecting catalysts doped with multiple elements, their synergistic effect can be exerted to shorten the lifetime of the transition intermediate product of aromatic methylamine, so that it can be quickly converted into aromatic methylamine, thereby improving the reaction efficiency and realizing the rapid conversion of aromatic carboxylic acid to aromatic methylamine.

[0051] Catalytic hydrogenation reactions are closely linked not only to the adsorption and dissociation of hydrogen but also to the adsorption of substrate molecules and the desorption of product molecules. By selecting at least three of the aforementioned catalysts, the hydrogenation activity of single-atom catalysts can be surpassed, thereby achieving highly efficient hydrogenation reactions. The inventors' research has shown that Au (gold) and Ag (silver) exhibit strong synergistic effects with the other catalysts mentioned above. Therefore, a mixture of gold and silver with other catalysts is preferred as the active component. Furthermore, the shared use of multiple catalysts plays a significant role in improving catalytic stability.

[0052] In the present invention, the absolute amount of the catalyst can be adjusted according to parameters such as the amount of reactants such as aromatic carboxylic acid and ammonia in the reactor and the size of the reactor.

[0053] According to one embodiment of the present invention, the carrier of the supported catalyst is selected from SiO2, Al2O3, and TiO2. Preferably, the carrier is Al2O3. Such carriers can provide multiple pores, large specific surface area, and high dispersibility.

[0054] According to one embodiment of the present invention, the active component accounts for 1-10% by mass of the supported catalyst. For example, it may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., and preferably 5-8%. This ratio provides a large specific surface area for the catalytic hydrogenation reaction.

[0055] According to one embodiment of the present invention, the active components of the supported catalyst include the following elements: Ag: 1 part by weight; P: 0~0.5 part by weight; Ti: 0~0.3 part by weight; Mo: 0~0.3 part by weight; Ru: 0~0.4 part by weight; Ni: 0~0.5 part by weight; Pt: 0~0.2 part by weight; Pd: 0~0.3 part by weight; Rh: 0~0.3 part by weight; Au: 0~0.5 part by weight; Co: 0~0.3 part by weight.

[0056] For example, the formula is Ag: 1 part by weight; P: 0.5 part by weight; Ti: 0.3 part by weight; Mo: 0.3 part by weight; Ru: 0.4 part by weight; Ni: 0.5 part by weight; Pt: 0.2 part by weight; Pd: 0.3 part by weight; Rh: 0.3 part by weight; Au: 0.5 part by weight; Co: 0.3 part by weight, or based on the above formula, reduce one or more of the other components except silver.

[0057] Preferably, the active component consists of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15.

[0058] Preferably, the active component is composed of Ag-Ni-Pt-Au-P-Rh in a weight ratio of 1:0.30:0.09:0.10:0.40:0.15.

[0059] Preferably, the active component is composed of Ag-Ni-Pt-Mo-Ti-Ru in a weight ratio of 1:0.30:0.09:0.15:0.10:0.25.

[0060] Preferably, the active component is composed of Ag-Ni-Pt-Au-Mo-Ru in a weight ratio of 1:0.30:0.09:0.10:0.05:0.25.

[0061] Preferably, the active component consists of Ag-Ni-Pt-Au-Co in a weight ratio of 1:0.30:0.09:0.40:0.20.

[0062] Preferably, the active component is composed of Ag-Ni-Pt-Au-P-Rh-Ru-Mo in a weight ratio of 1:0.30:0.09:0.40:0.40:0.15:0.25:0.05.

[0063] Preferably, the active component is composed of Ag-Ni-Pt-Au-P-Rh-Ru in a weight ratio of 1:0.30:0.09:0.40:0.40:0.15:0.25.

[0064] Preferably, the active component consists of Ag-P-Ni-Pt-Rh-Mo in a weight ratio of 1:0.40:0.30:0.09:0.15:0.05.

[0065] Preferably, the active component consists of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.10:0.30:0.09:0.15.

[0066] Preferably, the active component consists of Ag-Au-Mo-Ni-Pt-Ru in a weight ratio of 1:0.10:0.05:0.30:0.09:0.25.

[0067] In this formulation, silver is the primary catalyst, with the other components serving as auxiliary catalysts. When the amounts of all elements other than silver are zero, pure silver is used as the catalyst. In the present invention, at least two elements other than silver are preferably included as auxiliary catalysts. By setting these weight ratios, the catalytic activity of silver in the catalytic hydrogenation reaction of aromatic carboxylic acids can be enhanced.

[0068] By pre-loading the above-mentioned supported gas-solid phase catalyst in the reactor, the catalytic hydrogenation reaction of the aromatic carboxylic acid can be carried out continuously.

[0069] Figure 2 A block diagram of a reaction system suitable for an embodiment of the present invention is shown.

[0070] like Figure 2 As shown, aromatic carboxylic acid, ammonia and carrier gas are input into mixer 1 for mixing and preheating. When mixing and preheating are completed, the preheated mixed gas is input from mixer 1 into reactor 2. The temperature and pressure are controlled in reactor 2. The mixed gas undergoes a gas-phase continuous reaction under the catalysis of a supported gas-solid catalyst preinstalled in reactor 2. The obtained products include aromatic methylamine and by-products such as amides and nitriles, and the products are collected in collector 3.

[0071] The following examples are provided to illustrate the reaction process of the present invention.

[0072] Example 1.

[0073] A supported catalyst having an active component composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15 and an Al2O3 carrier was loaded in a fluidized bed.

[0074] Benzoic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:15:40 and heated to 200°C during mixing to produce a mixed gas. The mixed gas was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 420°C and the pressure was maintained at 0.08 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0075] After testing, the product contained benzylamine, benzonitrile and a small amount of benzamide, among which the conversion rate of benzoic acid was 99.8%, and the molar yield of benzylamine reached 50.1%.

[0076] Example 2.

[0077] Based on Example 1, the molar ratio of benzoic acid, ammonia, and nitrogen was adjusted to 1:20:40, the reaction temperature was controlled at 560°C, the reaction pressure was controlled at 0.25 MPa, and the residence time of the mixed gas in the fluidized bed was controlled at 28 seconds. The product in the fluidized bed was collected in a trap for detection.

[0078] After testing, the product contained benzylamine, benzonitrile and a small amount of benzamide, among which the conversion rate of benzoic acid was 99.9% and the molar yield of benzylamine reached 56.3%.

[0079] Example 3.

[0080] Based on Example 1, the molar ratio of benzoic acid, ammonia, and nitrogen was adjusted to 1:15:12.5, the reaction temperature was controlled at 380°C, the reaction pressure was controlled at 0.05 MPa, and the residence time of the mixed gas in the fluidized bed was controlled at 60 seconds. The product in the fluidized bed was collected in a trap for detection.

[0081] After testing, the product contained benzylamine, benzonitrile and a small amount of benzamide, among which the conversion rate of benzoic acid was 99.9% and the molar yield of benzylamine reached 39.2%.

[0082] Example 4.

[0083] A supported catalyst having an active component composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15 and an Al2O3 carrier was loaded in a fluidized bed.

[0084] Benzoic acid and ammonia were mixed in a mixer at a molar ratio of 1:160 and heated to 200°C during mixing to produce a gas mixture. The gas mixture was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 560°C and the pressure was maintained at 0.25 MPa. The residence time of the gas mixture in the fluidized bed was 10 seconds. The product in the fluidized bed was collected in a trap for detection.

[0085] The product was tested and found to contain benzylamine, benzonitrile, and a small amount of benzamide. The conversion rate of benzoic acid was 99.8%, and the molar yield of benzylamine reached 54.9%. Therefore, using ammonia as the carrier gas resulted in a high conversion rate and yield.

[0086] Example 5.

[0087] A supported catalyst having an active component composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15 and an Al2O3 carrier was loaded in a fluidized bed.

[0088] Benzoic acid, ammonia, and hydrogen were mixed in a mixer at a molar ratio of 1:100:40 and heated to 200°C during mixing to produce a gas mixture. The gas mixture was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 420°C and the pressure was maintained at 0.10 MPa. The residence time of the gas mixture in the fluidized bed was 10 seconds. The product in the fluidized bed was collected in a trap for detection.

[0089] The product was tested and found to contain benzylamine, benzonitrile, and a small amount of benzamide. The conversion of benzoic acid was 99.8%, and the molar yield of benzylamine reached 57.6%. This indicates that both the conversion of benzoic acid and the molar yield of benzylamine were high when hydrogen was used as the carrier gas.

[0090] Example 6.

[0091] A supported catalyst having an active component composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15 and an Al2O3 carrier was loaded in a fluidized bed.

[0092] Benzoic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:15:135 and heated to 200°C during mixing to produce a gas mixture. The gas mixture was introduced from the mixer into a fluidized bed at a controlled temperature of 420°C and a pressure of 0.08 MPa. The residence time of the gas mixture in the fluidized bed was 10 seconds. The product in the fluidized bed was collected in a trap for detection.

[0093] After testing, the product contains benzylamine, benzonitrile and benzamide, among which the conversion rate of benzoic acid is 79.1% and the molar yield of benzylamine reaches 13.7%.

[0094] Example 7.

[0095] A supported catalyst having an active component composed of Ag-Ni-Pt-Au-P-Rh in a weight ratio of 1:0.30:0.09:0.10:0.40:0.15 and an Al2O3 carrier was loaded in a fluidized bed.

[0096] Benzoic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:20:40 and heated to 200°C during mixing to produce a gas mixture. The gas mixture was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 380°C and the pressure was maintained at 0.08 MPa. The residence time of the gas mixture in the fluidized bed was 27.5 seconds. The product in the fluidized bed was collected in a trap for detection.

[0097] After testing, the product contained benzylamine, benzonitrile and a small amount of benzamide, among which the conversion rate of benzoic acid was 99.2%, and the molar yield of benzylamine reached 42.1%.

[0098] Example 8.

[0099] Based on Example 7, the reaction temperature was adjusted from 380°C to 560°C at intervals of 20°C, and the products were tested to obtain the benzoic acid conversion rates and molar yields of benzylamine at different reaction temperatures, as shown in Table 1.

[0100] Table 1

[0101] Serial number Reaction temperature / ℃ Benzoic acid conversion rate / % Benzylamine molar yield / % 1 400 99.6 47.8 2 420 99.8 50.4 3 440 99.8 51.3 4 460 99.0 44.5 5 480 98.7 41.2 6 500 98.2 40.4 7 540 98.4 34.6 8 560 98.1 30.8

[0102] Example 9.

[0103] Based on Example 7, the reaction temperature was set to 420° C., the reaction pressure was adjusted to 0.07 and 0.10 MPa, and the products were detected to obtain the benzoic acid conversion rate and the molar yield of benzylamine under different reaction pressures as shown in Table 2.

[0104] Table 2

[0105] Serial number Reaction temperature / ℃ Reaction pressure / MPa Benzoic acid conversion rate / % Benzylamine molar yield / % 1 420 0.07 99.5 49.2 2 420 0.10 99.8 49.9

[0106] Example 10.

[0107] Based on Example 7, different active components of the supported catalyst were substituted and the reaction temperature was set to 420° C. The products were tested to obtain the benzoic acid conversion rates and molar yields of benzylamine in the presence of different supported catalysts, as shown in Table 3.

[0108] Table 3

[0109] Serial number Supported catalyst active components Benzoic acid conversion rate / % Benzylamine molar yield / % 1 Ag-Ni-Pt-Mo-Ti-Ru1:0.30:0.09:0.15:0.10:0.25 99.7 50.0 2 Ag-Ni-Pt-Au-Mo-Ru1:0.30:0.09:0.10:0.05:0.25 99.2 48.9 3 Ag-Ni-Pt-Au-Co1:0.30:0.09:0.40:0.20 99.8 49.3 4 Ag-Ni-Pt-Au-P-Rh-Ru-Mo1:0.30:0.09:0.40:0.40:0.15:0.25:0.05 99.9 51.7 5 Ag-Ni-Pt-Au-P-Rh-Ru1:0.30:0.09:0.40:0.40:0.15:0.25 99.8 51.5

[0110] Example 11.

[0111] The active components loaded in the fluidized bed are composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15, and the carrier is a supported catalyst of TiO2.

[0112] 1,3-Benzenedicarboxylic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:15:40 and heated to 350°C during mixing to produce a mixed gas. The mixed gas was then introduced from the mixer into a fluidized bed. The reaction temperature was controlled at 460°C and the pressure was maintained at 0.08 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0113] After testing, the product contained 1,3-phenylenediamine, isophthalonitrile and a small amount of 3-cyanobenzamide, among which the conversion rate of 1,3-phthalic acid was 99.6%, and the molar yield of 1,3-phenylenediamine reached 44.5%.

[0114] Example 12.

[0115] Based on Example 11, different active components of the supported catalyst were substituted and the reaction temperature was set to 420° C. The products were tested to obtain the conversion rates of 1,3-benzenedicarboxylic acid and the molar yields of 1,3-phenylenediamine in the presence of different supported catalysts, as shown in Table 4.

[0116] Table 4

[0117] Serial number Supported catalyst active components 1,3-Phenylenedicarboxylic acid conversion rate / % 1,3-phenylenediamine molar yield / % 1 Ag-Ni-Pt-Au-P-Rh1:0.30:0.09:0.10:0.40:0.15 99.4 45.3 2 Ag-Ni-Pt-Mo-Ti-Ru1:0.30:0.09:0.15:0.10:0.25 99.2 44.8

[0118] Example 13.

[0119] The active components loaded in the fluidized bed are composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.40:0.30:0.09:0.15, and the carrier is a supported catalyst of SiO2.

[0120] 1,4-Benzenedicarboxylic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:20:40 and heated to 350°C during mixing to produce a mixed gas. The mixed gas was then introduced from the mixer into a fluidized bed, where the reaction temperature was controlled at 440°C and the pressure was maintained at 0.08 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0121] After testing, the product contained 1,4-phenylenediamine, terephthalonitrile and a small amount of 4-cyanobenzamide, among which the conversion rate of 1,4-phthalic acid was 99.8%, and the molar yield of 1,4-phenylenediamine reached 42.3%.

[0122] Example 14.

[0123] Based on Example 13, different active components of the supported catalyst were substituted and the reaction temperature was set to 420° C. The products were tested and the conversion rates of 1,4-benzenedicarboxylic acid and the molar yields of 1,4-phenylenediamine in the presence of different supported catalysts were obtained, as shown in Table 5.

[0124] Table 5

[0125] Serial number Supported catalyst active components 1,4-phthalic acid conversion rate / % 1,4-phenylenediamine molar yield / % 1 Ag-Ni-Pt-Au-P-Rh1:0.30:0.09:0.10:0.40:0.15 99.5 43.9 2 Ag-Ni-Pt-Mo-Ti-Ru1:0.30:0.09:0.15:0.10:0.25 99.0 42.6

[0126] Example 15.

[0127] The active components loaded in the fluidized bed are composed of Ag-P-Ni-Pt-Rh-Mo in a weight ratio of 1:0.40:0.30:0.09:0.15:0.05, and the carrier is Al2O3.

[0128] 2-Naphthoic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:20:40 and heated to 300°C during mixing to produce a gas mixture. The gas mixture was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 480°C and the pressure was maintained at 0.01 MPa. The residence time of the gas mixture in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0129] After testing, the product contains 2-naphthylamine, 2-naphthylcarbonitrile and a small amount of 2-naphthylamide, among which the conversion rate of 2-naphthoic acid is 98.9%, and the molar yield of 2-naphthylamine reaches 38.7%.

[0130] Example 16.

[0131] Based on Example 15, different active components of the supported catalyst were substituted, the reaction temperature was set to 420°C, and the reaction pressure was set to 0.08 MPa. The products were tested and the conversion rates of 2-naphthoic acid and the molar yields of 2-naphthylmethylamine in the presence of different supported catalysts were shown in Table 6.

[0132] Table 6

[0133] Serial number Supported catalyst active components 2-Naphthoic acid conversion rate / % 2-Naphthylmethylamine molar yield / % 1 Ag-Ni-Pt-Au-P-Rh1:0.30:0.09:0.10:0.40:0.15 99.1 39.1 2 Ag-Ni-Pt-Mo-Ti-Ru1:0.30:0.09:0.15:0.10:0.25 99.1 38.0

[0134] Example 17.

[0135] The active components loaded in the fluidized bed are composed of Ag-Ni-Pt-Au-P-Rh in a weight ratio of 1:0.30:0.09:0.40:0.40:0.15, and the carrier is Al2O3.

[0136] 1,8-Naphthalenedicarboxylic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:20:40 and heated to 300°C during mixing to produce a gas mixture. The gas mixture was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 420°C and the pressure was maintained at 0.08 MPa. The residence time of the gas mixture in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0137] After testing, the product contains 1,8-naphthalenediamine, 1,8-naphthalenedinitrile and a small amount of 1,8-naphthalenedicarboxylic acid. The conversion rate of 1,8-naphthalenedicarboxylic acid is 99.4%, and the molar yield of 1,8-naphthalenediamine reaches 32.8%.

[0138] Example 18.

[0139] Based on Example 17, different aromatic carboxylic acids were substituted, while other conditions remained unchanged. The products were tested to obtain the conversion rates of different aromatic carboxylic acids and the molar yields of aromatic methylamines, as shown in Table 7.

[0140] Table 7

[0141] Serial number Aromatic carboxylic acids Aromatic carboxylic acid conversion rate / % Molar yield of aromatic methylamine / % 1 1-Naphthoic acid 99.0 37.6 2 1-Anthracenecarboxylic acid 98.9 34.6 3 2-Anthracenecarboxylic acid 98.3 34.2 4 1,3-Naphthalenedicarboxylic acid 99.2 31.3

[0142] Example 19.

[0143] Based on Example 17, the active components of the supported catalyst were replaced with Ag-Ni-Pt-Au-P-Rh in a weight ratio of 1:0.30:0.09:0.10:0.40:0.15. Different aromatic carboxylic acids were used, and different preheating temperatures were set, while other conditions remained unchanged. The products were tested for the conversion rates of different aromatic carboxylic acids and the molar yields of aromatic methylamines, as shown in Table 8.

[0144] Table 8

[0145] Serial number Aromatic carboxylic acids Preheating temperature / ℃ Aromatic carboxylic acid conversion rate / % Molar yield of aromatic methylamine / % 1 1,7-Naphthalenedicarboxylic acid 300 99.1 30.8 2 2-Phenanthroline carboxylic acid 400 98.7 31.3 3 trimellitic acid 350 98.2 25.4

[0146] Example 20.

[0147] The active components loaded in the fluidized bed are composed of Ag-Au-P-Ni-Pt-Rh in a weight ratio of 1:0.10:0.40:0.30:0.09:0.15, and the carrier is Al2O3.

[0148] 1,3-Benzenedicarboxylic acid, ammonia, and hydrogen were mixed in a mixer at a molar ratio of 1:20:40 and heated to 350°C during mixing to produce a mixed gas. The mixed gas was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 420°C and the pressure was maintained at 0.10 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0149] After testing, the product contained 1,3-phenylenediamine, isophthalonitrile and a small amount of 3-cyanobenzamide, among which the conversion rate of 1,3-phthalic acid was 99.8%, and the molar yield of 1,3-phenylenediamine reached 40.6%.

[0150] Example 21.

[0151] The active components loaded in the fluidized bed are composed of Ag-P-Ni-Pt-Rh in a weight ratio of 1:0.10:0.30:0.09:0.15, and the carrier is Al2O3.

[0152] 1,3-Benzenedicarboxylic acid, ammonia, and argon were mixed in a mixer at a molar ratio of 1:20:40 and heated to 350°C during mixing to produce a mixed gas. The mixed gas was then introduced from the mixer into a fluidized bed, where the reaction temperature was controlled at 460°C and the pressure was maintained at 0.08 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0153] After testing, the product contains 1,3-phenylenediamine, isophthalonitrile and a small amount of 3-cyanobenzamide, benzonitrile and benzylamine. Among them, the conversion rate of 1,3-phthalic acid is 99.2%, and the molar yield of 1,3-phenylenediamine reaches 45.7%.

[0154] Example 22.

[0155] The active components loaded in the fluidized bed are composed of Ag-Au-Mo-Ni-Pt-Ru in a weight ratio of 1:0.10:0.05:0.30:0.09:0.25, and the carrier is Al2O3.

[0156] 9-Anthracenecarboxylic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:30:40 and heated to 350°C during mixing to produce a mixed gas. The mixed gas was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 480°C and the pressure was maintained at 0.01 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0157] After testing, the product contained 9-anthracenemethylamine, 9-anthracenecarbonitrile and a small amount of 9-anthracenecarboxamide, among which the conversion rate of 9-anthracenecarboxylic acid was 99.1%, and the molar yield of 9-anthracenemethylamine reached 33.9%.

[0158] Example 23.

[0159] The active components loaded in the fluidized bed are composed of Ag-Au-Mo-Ni-Pt-Ru in a weight ratio of 1:0.10:0.05:0.30:0.09:0.25, and the carrier is Al2O3.

[0160] 3-Phenanthric acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:20:40 and heated to 500°C during mixing to produce a mixed gas. The mixed gas was then passed from the mixer into a fluidized bed. The reaction temperature was controlled at 500°C and the pressure was maintained at 0.10 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0161] After testing, the product contained 3-phenanthrenylamine, 3-phenanthrenylcarbonitrile and a small amount of 3-phenanthrenylcarboxamide, among which the conversion rate of 3-phenanthrenylcarboxylic acid was 99.3%, and the molar yield of 3-phenanthrenylamine reached 32.6%.

[0162] Example 24.

[0163] The active components loaded in the fluidized bed are composed of Ag-Au-Mo-Ni-Pt-Ru in a weight ratio of 1:0.10:0.05:0.30:0.09:0.25, and the carrier is Al2O3.

[0164] 1,3,5-Benzenetricarboxylic acid, ammonia, and nitrogen were mixed in a mixer at a molar ratio of 1:30:40 and heated to 350°C during mixing to produce a mixed gas. The mixed gas was then introduced from the mixer into a fluidized bed. The reaction temperature was controlled at 460°C and the pressure was maintained at 0.10 MPa. The residence time of the mixed gas in the fluidized bed was 30 seconds. The product in the fluidized bed was collected in a trap for detection.

[0165] After testing, the product contains 1,3,5-benzenetrimethylamine, 1,3,5-benzenetricarboxylic acid, benzonitrile and a small amount of benzamide. Among them, the conversion rate of 1,3,5-benzenetricarboxylic acid is 98.1%, and the molar yield of 1,3,5-benzenetrimethylamine reaches 21.8%.

[0166] Although a number of embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may devise numerous modifications, variations, and alternatives without departing from the concept and spirit of the present invention. It should be understood that in practicing the present invention, various alternatives to the embodiments of the present invention described herein may be employed. The appended claims are intended to define the scope of the present invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for preparing aromatic methylamine, characterized in that: include: Aromatic carboxylic acid, ammonia, and carrier gas are fed into a mixer for mixing and preheating. When mixing and preheating are completed, the preheated mixed gas is fed from the mixer into a reactor. The temperature and pressure are controlled in the reactor, and the mixed gas undergoes a gas-phase continuous reaction under the catalysis of a supported gas-solid phase catalyst pre-installed in the reactor. Including steps: In the first step, the aromatic carboxylic acid, the ammonia gas and the carrier gas are mixed and preheated to a gaseous state to obtain the mixed gas; In the second step, the mixed gas is subjected to a gas-solid phase catalytic reaction at a reaction temperature of 380-560° C. and a reaction pressure of 0.05-0.25 MPa to obtain aromatic methylamine; in the mixed gas, ammonia is in excess relative to the aromatic carboxylic acid, and ammonia accounts for 10-100% of the total volume of ammonia and carrier gas; The aromatic carboxylic acid is selected from the group consisting of: C(2+4n)H(2n+4-m)(COOH)m, wherein n is selected from 1, 2 or 3; When n = 1, m = 1, 2 or 3; When n=2, m=1 or 2; When n=3, m=1; The active components of the supported catalyst are selected from at least three elements of Au, P, Ti, Mo, Ru, Ni, Pt, Pd, Rh, Ag, and Co; The active components of the supported catalyst include the following elements: Ag: 1 part by weight; P: 0-0.5 part by weight; Ti: 0-0.3 part by weight; Mo: 0-0.3 part by weight; Ru: 0-0.4 part by weight; Ni: 0-0.5 part by weight; Pt: 0-0.2 part by weight; Pd: 0-0.3 part by weight; Rh: 0-0.3 part by weight; Au: 0-0.5 part by weight; Co: 0-0.3 part by weight; The carrier of the supported catalyst is selected from any one of SiO2, Al2O3, and TiO2; The carrier gas is selected from at least one of nitrogen, carbon dioxide, helium, argon, hydrogen and ammonia.

2. The method according to claim 1, characterized in that The carrier gas is selected from at least one of hydrogen and ammonia.

3. The method according to claim 1, characterized in that The active components of the supported catalyst include at least Au and Ag.

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