Method for co-producing diphenylamine and quinoline

Abstract

The present invention belongs to the technical field of fine chemical engineering, and particularly relates to a method for co-producing diphenylamine and quinolone. The method comprises: subjecting aniline and a catalyst to a contact reaction in the presence of propylene, so as to obtain a reaction product containing diphenylamine and quinoline. In the method provided in the present invention, by introducing propylene into a reaction system, diphenylamine and quinoline can be co-produced, the conversion rate of aniline is high, and the total selectivity of the diphenylamine and quinoline is high.

Description

Method for co-producing diphenylamine and quinoline

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202311712982.2 filed on December 13, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The invention belongs to the technical field of fine chemicals, and particularly relates to a method for co-producing diphenylamine and quinoline. Background Art

[0004] Diphenylamine is a widely used chemical product, with important applications in rubber additives, dyes, explosives stabilizers, fruit preservatives, and pharmaceuticals. Currently, there are over 20 methods for synthesizing diphenylamine. Raw materials include aniline, phenol, cyclohexanone, N-cyclohexylaniline, and dicyclohexylamine, and catalysts primarily include aluminum trichloride, boron trifluoride, activated alumina, and zeolite molecular sieves. Among these methods, the method using only aniline as a raw material offers the best atom economy, the strongest feasibility for large-scale production, and has already been industrialized. The production processes for synthesizing diphenylamine from aniline include batch, gas-phase, and liquid-phase continuous methods, with the liquid-phase continuous method currently being the most advanced. However, these processes suffer from low aniline conversion rates, severely limiting the efficiency of these processes and presenting a major challenge in the current industrial production of diphenylamine.

[0005] CN1186802A discloses a process for the continuous synthesis of diphenylamine from aniline using hydrogen. This process uses refined gas (approximately 75% hydrogen and 25% nitrogen) from a synthetic ammonia plant as the hydrogen source, and a gas-phase circulation system is constructed between the diphenylamine plant and the synthetic ammonia compression section. This process has the advantage of fully utilizing hydrogen resources, effectively increasing the aniline conversion rate and extending the catalyst life in the diphenylamine production process. Although this hydrogenation effect is relatively significant, the aniline conversion rate still does not exceed 30%.

[0006] CN103044270A also reports a process for continuously synthesizing diphenylamine from aniline using hydrogen, which aims to improve the conversion rate of aniline by developing a hydrogen-dissolving process. This process focuses on contacting the aniline feedstock with hydrogen before it enters the reactor, dissolving the hydrogen into the aniline feedstock. The hydrogen-dissolved aniline feedstock then enters the aniline continuous diphenylamine synthesis reactor, where the aniline-to-diphenylamine reaction proceeds. This method has the advantage of improving the efficiency of diphenylamine synthesis from aniline by dissolving hydrogen. However, dissolving hydrogen does not effectively improve the conversion rate of aniline.

[0007] Quinoline is an important aromatic heterocyclic compound. Quinoline-based compounds have been widely used and studied in fields such as coordination chemistry, organometallic chemistry, asymmetric organic synthesis, and materials chemistry. In real-world applications, they play a vital role in pharmaceuticals, biological reagents, dyes, and other fields. In industrial production, quinoline is primarily obtained through coal tar extraction, Skraup synthesis, Doebner-Von Miller synthesis, and reductive carbonylation of nitrobenzene. Despite their widespread application, the production process of quinoline and quinoline-based compounds is plagued by high energy consumption and severe pollution.

[0008] Tetrahedron Letters, 2014, 5(22), 3319-3321. A method for synthesizing quinoline is disclosed. This method uses acrolein diethyl acetal and aniline as raw materials, uses a metal-loaded zeolite as a solid catalyst, and synthesizes the quinoline compound with microwave assistance, achieving a product yield of 83.1%. Although this method can produce quinoline products in high yield, the microwave-assisted synthesis conditions are not yet suitable for industrial production. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the problems of low aniline conversion rate and low product added value in the prior art, and to provide a method for co-producing diphenylamine and quinoline. The method has the characteristics of high aniline conversion rate, high total selectivity of diphenylamine and quinoline, and high product added value, and has good industrial application prospects.

[0010] The invention provides a method for co-producing diphenylamine and quinoline. The method comprises: in the presence of propylene, contacting aniline with a catalyst to react to obtain a reaction product containing diphenylamine and quinoline.

[0011] Both diphenylamine and quinoline can be produced using aniline as a raw material. Among currently established chemical production technologies, only the continuous synthesis of diphenylamine from aniline can simultaneously produce diphenylamine and quinoline. However, the quinoline yield is extremely low, typically below 1%, and cannot meet practical needs. The method for co-producing diphenylamine and quinoline provided by the present invention effectively improves the conversion rate of aniline and the selectivity of quinoline by introducing propylene into the reaction system. The high overall selectivity of diphenylamine and quinoline significantly increases the added value of the product. DETAILED DESCRIPTION

[0012] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0013] The invention provides a method for co-producing diphenylamine and quinoline. The method comprises: in the presence of propylene, contacting aniline with a catalyst to react to obtain a reaction product containing diphenylamine and quinoline.

[0014] Both diphenylamine and quinoline can be produced using aniline as a raw material. However, in currently mature chemical production processes, the yield of quinoline in the continuous synthesis of diphenylamine from aniline is extremely low and difficult to separate. For example, CN103044270A discloses a process for synthesizing diphenylamine from aniline. The conversion rate of aniline is less than 30%, and the selectivity of quinoline in the reaction solution is less than 1%. As a result, the extremely small amount of quinoline produced as a byproduct is difficult to recover as a high-value product.

[0015] The inventors of the present invention have discovered that, in the presence of propylene, aniline and a catalyst are contacted. A condensation reaction of the aniline occurs to produce diphenylamine, while the aniline and propylene react to produce quinoline. This allows for the co-production of diphenylamine and quinoline, while increasing the conversion of the raw aniline and yielding more high-value-added products. Thus, the method provided by the present invention can be carried out in a raw aniline condensation unit, resulting in a high conversion of aniline and a high overall selectivity for diphenylamine and quinoline. Furthermore, the method provided by the present invention does not produce byproducts such as water during the reaction, thus preventing poisoning of the catalyst and improving reaction stability.

[0016] According to some preferred embodiments of the present invention, the molar ratio of propylene to aniline is 1:(1-5), and can be, for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or other specific but non-limiting ratios. Preferably, the molar ratio of propylene to aniline is 1:(1.5-3). Adopting the above preferred embodiment is conducive to further improving the conversion rate of aniline, increasing the overall selectivity of diphenylamine and quinoline, and reducing the occurrence of side reactions.

[0017] The present invention has a wide range of selection conditions for the contact reaction. Preferably, the temperature of the contact reaction is 190-320°C, preferably 230-280°C, and the liquid hourly volume space velocity of aniline is 50-180h -1 , preferably 80-150h -1 , the reaction pressure is 3-8 MPa, preferably 5-7 MPa. Under the above preferred conditions, the conversion rate of raw material aniline can reach more than 35 mol%.

[0018] The diphenylamine and quinoline in the product obtained by the method provided by the present invention can be separated by any conventional method in the art, for example, by distillation, which is not particularly limited by the present invention.

[0019] According to the present invention, the contact reaction can be carried out in any conventional reactor in the art. Preferably, the contact reaction is carried out in a fixed bed reactor which is filled with a catalyst.

[0020] The present invention does not particularly limit the feeding method of propylene and aniline, and those skilled in the art may adjust the feeding method based on the actual reactor conditions and specific needs. For example, propylene and aniline may both be fed into the fixed-bed reactor via top-feed and passed through the catalyst bed; alternatively, propylene and aniline may both be fed into the fixed-bed reactor via bottom-feed and passed through the catalyst bed; or alternatively, propylene may be fed into the fixed-bed reactor via bottom-feed and aniline may be fed into the fixed-bed reactor via top-feed and passed through the catalyst bed.

[0021] In order to further improve the conversion rate of aniline, preferably, propylene and aniline are both fed into the fixed bed reactor in a bottom feeding manner and pass through the catalyst bed.

[0022] The present invention does not particularly limit the type and composition of the catalyst. Any catalyst conventionally used in the art for the condensation of aniline to produce diphenylamine can be used in the present invention, preferably a solid acid catalyst for the aniline condensation reaction. The present invention also does not particularly limit the source of the catalyst; the catalyst can be purchased commercially or prepared by any method known in the art.

[0023] According to some preferred embodiments of the present invention, the catalyst includes beta zeolite and a metal component.

[0024] According to the present invention, preferably, the molar ratio of silicon oxide to aluminum oxide in the beta zeolite is 20-100, preferably 50-70.

[0025] Preferably, the beta zeolite is H beta zeolite.

[0026] The present invention has a wide selection range for the metal component. In order to further improve the conversion rate of aniline and the total molar selectivity of diphenylamine and / or quinoline, preferably, the metal component is selected from at least one alkali metal, more preferably at least one of lithium, sodium and potassium.

[0027] According to some preferred embodiments of the present invention, based on the total mass of the catalyst, the content of the beta zeolite is 50-90wt%, for example, it can be 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt% or the like, or a range between any two thereof; the content of the metal component in terms of element is 0.1-40wt%, for example, it can be 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt% or the like, or a range between any two thereof.

[0028] More preferably, the beta zeolite content is 65-75 wt% based on the total mass of the catalyst, and the metal component content, calculated as an element, is 1-30 wt%. This preferred embodiment helps ensure a conversion rate of the raw material aniline exceeding 30%, and, under certain process conditions, suppresses side reactions, thereby producing more high-value-added products.

[0029] In the present invention, the content of metal components in the catalyst is measured by inductively coupled plasma optical emission spectrometer (ICP-OES) method.

[0030] According to some preferred embodiments of the present invention, the catalyst further comprises a binder to obtain a shaped catalyst body. The present invention provides a wide range of binders for selection; any binder that can be used for catalyst molding in the art can be used in the present invention. Preferably, the binder is alumina and / or silica, more preferably alumina.

[0031] Preferably, based on the total mass of the catalyst, the beta zeolite content is 50-90wt%, preferably 65-75wt%, the alkali metal content, calculated as metal elements, is 0.1-40wt%, preferably 1-30wt%, and the binder content is 0.5-49.9wt%, preferably 5-30wt%. This preferred composition is conducive to ensuring a raw material aniline conversion rate exceeding 30%, and under certain process conditions, suppressing side reactions, thereby obtaining more high-value-added products.

[0032] The present invention has no particular limitation on the shape of the catalyst, and those skilled in the art can select the size and morphology of the catalyst according to actual needs.

[0033] Preferably, the catalyst is in the form of strips or spherical particles. When in the form of strips, the cross-section can be cylindrical, clover-shaped or four-leaf-shaped. The cross-sectional width of the strip particles is 0.5-3.0 mm, preferably 1.0-2.0 mm. When in the form of spheres, the particle diameter is 0.5-5.0 mm, preferably 1.0-3.0 mm.

[0034] The present invention does not particularly limit the source of the catalyst, and the catalyst may be purchased commercially or prepared by any method known in the art. For example, the catalyst may be prepared by the method disclosed in CN200510047489.9. For example, the catalyst of the present invention may be prepared by the following method:

[0035] (1) contacting Hβ zeolite with a solution of a soluble compound of a metal component;

[0036] (2) subjecting the mixture obtained in step (1) to solid-liquid separation, washing and drying;

[0037] (3) The modified Hβ zeolite obtained in step (2), the binder and / or the binder precursor and the processing aid (such as an extrusion aid and a peptizing agent) are fully mixed and kneaded, and then formed into a mold, and then dried and calcined.

[0038] Preferably, the contact temperature of step (1) is 15-35° C. and the contact time is 0.5-2 h. For example, it can be carried out at room temperature.

[0039] Preferably, the concentration of the solution of the soluble compound of the metal component is 0.05-4 mol / L.

[0040] The present invention does not particularly limit the operating methods and conditions for the solid-liquid separation and washing, and those skilled in the art can select them according to actual needs. The solid-liquid separation can be performed, for example, by filtration. The present invention does not particularly limit the number of washing times, and can be adjusted according to actual washing conditions. The detergent used for the washing can be water.

[0041] The present invention has no particular limitation on the drying conditions in step (2). Preferably, the drying temperature is 100-130° C. and the drying time is 8-12 h.

[0042] In the present invention, the binder precursor refers to any substance that can be calcined to obtain the binder. For example, the precursor of aluminum oxide can be pseudo-boehmite and / or aluminum hydroxide, which are well known to those skilled in the art.

[0043] The present invention does not particularly limit the processing aid, and any conventional method in the art can be used. The present invention also does not particularly limit the amount of the processing aid, and those skilled in the art can select the appropriate amount based on actual needs. The extrusion aid can be, for example, sesbania powder, and the peptizing agent can be, for example, dilute nitric acid and / or citric acid. The concentration of the dilute nitric acid can generally be 3-15 wt%.

[0044] The present invention has no particular limitation on the molding method, and those skilled in the art can select the molding method according to actual needs, for example, it can be extrusion molding, tablet molding, ball molding, etc.

[0045] Preferably, the drying temperature in step (3) is 100-130° C. and the drying time is 8-12 h.

[0046] Preferably, the calcination temperature in step (3) is 450-550° C. and the calcination time is 6-8 h.

[0047] Another aspect of the present invention provides a method for producing diphenylamine and quinoline from aniline, comprising: reacting raw materials aniline and propylene at a reaction temperature of 190°C to 320°C, with a volume space velocity of 50h / min when the aniline solution is liquid; -1 -180h -1 Under the reaction conditions, the fixed bed reactor containing Hβ zeolite catalyst is used.

[0048] The present invention will be described in detail below through examples.

[0049] In the following examples and comparative examples, unless otherwise specified, all raw materials used were commercially available.

[0050] In the following examples and comparative examples, the calculation methods for the conversion of aniline, the selectivity of diphenylamine, and the selectivity of quinoline are as follows:

[0051] Aniline molar conversion:

[0052] Wherein, ω: aniline molar conversion, mol%; n0: molar number of aniline in the raw material, mol; n2: molar number of aniline in the reaction solution, mol.

[0053] Diphenylamine molar selectivity:

[0054] Wherein, ε1: molar selectivity of diphenylamine, mol%; n1: molar number of each product component in the reaction solution, mol; n3: molar number of diphenylamine in the reaction solution, mol.

[0055] Quinoline molar selectivity:

[0056] Wherein, ε2: quinoline molar selectivity, mol%; n1: molar number of each product component in the reaction solution, mol; n4: molar number of quinoline in the reaction solution, mol.

[0057] The reaction liquid refers to the mixed liquid phase obtained after the reaction. The "product" in the above formulas does not include aniline. The composition of the reaction liquid is analyzed with reference to standard HG / T5534-2019.

[0058] The catalysts used in the examples and comparative examples were prepared by the following method:

[0059] (1) contacting Hβ zeolite with a sodium chloride solution;

[0060] (2) filtering, washing and drying the mixture obtained in step (1);

[0061] (3) The modified Hβ zeolite obtained in step (2), the alumina binder precursor, the extrusion aid, and the peptizing agent are fully mixed and kneaded, and then extruded to obtain a strip catalyst with a diameter of 2 mm and a length of 2-3 mm, which is then dried and calcined.

[0062] The contact temperature of step (1) is 20°C and the contact time is 1.5 hours. The concentration of the sodium chloride solution is 0.5 mol / L. Step (2) is dried at 120°C for 10 hours, step (3) is dried at 120°C for 10 hours, and calcined at 500°C for 6 hours. The binder used is aluminum hydroxide, and the zeolite used is commercially available Hβ zeolite, with a specific surface area of ​​650m 2 / g, particle size 1.5-2mm.

[0063] The properties of the catalysts are listed in Table 1.

[0064] Table 1

[0065] Example 1

[0066] A stainless steel fixed-bed reactor with an inner diameter of 20 mm and a length of 1000 mm was loaded with 100 mL of catalyst. Aniline and propylene (commercially available, purity >99%) were introduced into the reactor via a bottom-feed system. The reaction product, exiting the reactor top, was cooled and then passed into a separator. The reaction was carried out for 48 hours under the reaction conditions listed in Table 2. The composition of the reaction product was analyzed by gas chromatography, and the product distribution is shown in Table 2 below.

[0067] Examples 2-7

[0068] The method of Example 1 was followed, except that the feeding method and reaction conditions were as shown in Table 2. After 48 hours of reaction, the composition of the reaction product was analyzed by gas chromatography, and the product distribution was shown in Table 2.

[0069] Examples 8-11

[0070] The method of Example 1 was followed, except that the feeding method and reaction conditions were as shown in Table 3. After 48 hours of reaction, the composition of the reaction product was analyzed by gas chromatography, and the product distribution was shown in Table 3.

[0071] Comparative Example 1

[0072] The method of Example 1 was followed, except that propylene was replaced with an equimolar amount of hydrogen. The specific reaction conditions and results are shown in Table 3.

[0073] Comparative Example 2

[0074] Diphenylamine was synthesized according to the method of CN106631829A, with a molar ratio of isopropyl alcohol to aniline of 1:1. The specific reaction conditions and results are shown in Table 3.

[0075] Table 2

[0076] Table 3

[0077] From the results of the above examples and comparative examples, it can be seen that the method provided by the present invention can co-produce diphenylamine and quinoline by introducing propylene into the reaction system, with high aniline conversion and high overall selectivity of diphenylamine and quinoline.

[0078] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for co-producing diphenylamine and quinoline, characterized in that: The method comprises: in the presence of propylene, contacting aniline with a catalyst to react, and obtaining a reaction product containing diphenylamine and quinoline.

2. The method according to claim 1, wherein: The molar ratio of propylene to aniline is 1:(1-5), preferably 1:(1.5-3).

3. The method according to claim 1 or 2, wherein: The contact reaction temperature is 190-320°C, preferably 230-280°C, and the liquid hourly volume space velocity of aniline is 50-180h -1 , preferably 80-150h -1 , the reaction pressure is 3-8MPa, preferably 5-7MPa.

4. The method according to any one of claims 1 to 3, wherein: The contact reaction is carried out in a fixed bed reactor.

5. The method according to claim 4, wherein: Propylene and aniline are both fed into the fixed bed reactor by top feeding and pass through the catalyst bed; or, Propylene and aniline are fed into the fixed bed reactor by bottom feeding and pass through the catalyst bed; or, Propylene is fed into the fixed bed reactor by a bottom feeding method, and aniline is fed into the fixed bed reactor by a top feeding method and passes through the catalyst bed.

6. The method according to any one of claims 1 to 5, wherein: The catalyst is an aniline condensation reaction catalyst; Preferably, the catalyst comprises beta zeolite and a metal component.

7. The method according to claim 6, wherein: The molar ratio of silicon oxide to aluminum oxide in the beta zeolite is 20-100; Preferably, the beta zeolite is H beta zeolite.

8. The method according to claim 6 or 7, wherein: The metal component is selected from at least one of alkali metals, preferably at least one of lithium, sodium and potassium.

9. The method according to any one of claims 6 to 8, wherein: Based on the total mass of the catalyst, the content of the beta zeolite is 50-90wt%, and the content of the metal component in terms of element is 0.1-40wt%; Preferably, based on the total mass of the catalyst, the content of the beta zeolite is 65-75 wt%, and the content of the metal component in terms of element is 1-30 wt%.

10. The method according to any one of claims 7 to 9, wherein: The catalyst further contains a binder, preferably, the binder is alumina and / or silica, more preferably alumina; Preferably, based on the total mass of the catalyst, the content of the beta zeolite is 50-90wt%, preferably 65-75wt%, the content of the alkali metal component in terms of metal element is 0.1-40wt%, preferably 1-30wt%, and the content of the binder is 0.5-49.9wt%, preferably 5-30wt%.

Images