Catalyst for producing 1, 5-pentamethylene diisocyanate by phosgenation method and preparation method thereof

Abstract

The invention discloses a catalyst for producing 1, 5-pentamethylene diisocyanate by phosgenation and a preparation method thereof, a catalyst carrier with a hierarchical pore structure is selected, and the particle size of the catalyst is homogenized by a screening process; the screened catalyst particles are subjected to surface pretreatment, and the surface hydroxyl content, the microporous / mesoporous structure and the distribution of Lewis acid active sites are regulated and modified while the surface cleanness of the carrier is ensured; the Lewis acid catalyst is loaded on the surface of the carrier by adopting an impregnation method, and the catalytic performance of the catalyst is optimized and adjusted by regulating and controlling the particle size and the catalyst loading amount. The catalyst can effectively promote wetting and diffusion of a gas-liquid interface, improve the utilization rate of reaction active sites, reduce the activation energy barrier required by the reaction and enable the reaction to be efficiently carried out under relatively mild conditions. The reaction time is shortened, the reaction efficiency is improved, and the application prospect and industrial popularization value are high.

Description

Technical Field

[0001] This invention belongs to the field of advanced chemical new materials, specifically relating to a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate and its preparation method. Background Technology

[0002] In the phosgenation reaction of 1,5-pentanediisocyanate, gaseous phosgene and liquid pentanediamine or its derivatives are typically used as the main reactants to generate the target product under the action of a catalyst. This reaction is a typical gas-liquid heterogeneous reaction system, and its reaction kinetics are significantly affected by mass transfer processes and interfacial contact efficiency. In traditional production processes, insufficient contact, a lack of efficient catalytic materials, and limited contact area between reactants lead to inadequate mixing of the gas and liquid phases, resulting in high mass transfer resistance and consequently, slow reaction rates and low conversion rates. Furthermore, to increase the reaction rate, operation under high temperature and pressure conditions is often required. This not only increases the probability of side reactions, such as the formation of impurities like ureas and carbamates, but also exacerbates solvent evaporation losses, leading to additional separation and purification burdens and environmental pollution risks. In addition, high-temperature, long-duration reactions accelerate equipment corrosion, especially in the presence of phosgene, placing higher demands on reactor materials and further increasing investment and operating / maintenance costs.

[0003] Optimizing reaction conditions, improving reaction selectivity and energy utilization efficiency have become key factors in upgrading the industrial production technology of 1,5-pentanediisocyanate. Summary of the Invention

[0004] The main objective of this invention is to provide a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate and its preparation method, thereby overcoming the shortcomings of the prior art.

[0005] To achieve the above invention, the technical solution adopted by the present invention includes: a catalyst for the production of 1,5-pentanediisocyanate by phosgenation, characterized in that: the catalyst is a supported catalyst composed of a support and a surface Lewis acid catalyst. The support is one or more of activated carbon, alumina, silica, or molecular sieve catalyst. The Lewis acid catalyst is one or a mixture of two or more of AlCl3, FeBr3, FeCl3, TiCl4, ZnCl2, Al2O3, and Fe2O3.

[0006] The molecular sieve catalyst is one or a mixture of two or more of SAPO-11, ZSM-5, aluminum phosphate molecular sieve catalyst, TS molecular sieve catalyst, MCM series molecular sieve catalyst, and SBA molecular sieve catalyst.

[0007] The activated carbon has a particle size of 0.15~0.18 mm and a surface pore size of 50 nm~1 μm; The alumina has a particle size of 0.15~0.18 mm and a surface pore size of 1 μm~20 μm; The silica has a particle size of 0.15~0.18 mm and a surface pore size of 0.2 nm~200 nm; The molecular sieve has a particle size of 0.15~0.18 mm and a surface pore size of 0.2 nm~2 nm.

[0008] A method for preparing a catalyst for the phosgenation production of 1,5-pentanediisocyanate is characterized by: employing an impregnation method; the support being one or a mixture of activated carbon and silicon dioxide; and the Lewis acid catalyst being Al2O3 or Fe2O3. The carrier is activated carbon, and the specific steps of the preparation method are as follows: Step 1, Pretreatment: First, the activated carbon is washed with water to remove ash, then soaked in nitric acid solution for surface acid modification, and finally dried and activated to form a Lewis acid active phase on the surface. Step 2, Grinding and Sieving: The mesh size of the sieve is 80-100 mesh; Step 3, Impregnation: Aluminum nitrate and ferric nitrate are selected as precursors to prepare the impregnation solution. During the impregnation process, the solution is stirred for 30 minutes every 4 hours. Step four, drying and calcination: the loading of the active component on the support surface in the obtained catalyst is 2% to 20%; The carrier is silicon dioxide, and the specific steps of the preparation method are as follows: Step 1, Pretreatment: First, the silicon oxide is calcined to remove impurities, and then the surface is silanized. Steps two, three, and four are the same as the corresponding steps when the carrier is activated carbon; A mixed carrier is used, in which activated carbon and silicon dioxide are mixed at a mass ratio of 1:1 to 3:1. In the preparation method, the pretreatment in step one is carried out according to the method of the corresponding single carrier, and steps two, three and four are the same as the corresponding steps when the carrier is activated carbon or silicon dioxide.

[0009] Furthermore, the carrier is activated carbon: Step one, preprocessing, specifically involves: (1) Boil the activated carbon carrier in process water for 1-5 hours, and repeat the water washing and ash removal treatment 1-5 times. (2) Soak in HNO3 solution at 60~80 ℃ and 10%~40% concentration for 2~6 h to perform surface acid modification; (3) Place the surface acid-modified activated carbon carrier in an oven and dry it at 100 ℃~160 ℃ for 6~24 hours. h, then perform drying and activation; In step three, the liquid-solid mass ratio of the impregnation solution to the carrier is 1:1 to 10:1, the impregnation temperature is controlled at 10 to 60°C, and the time is 12 to 24 hours. In step four, the calcination atmosphere is an air atmosphere, and the heating rate is 2~5 ℃ / min; the calcination method is segmented calcination, calcining at 300 ℃ for 2~6 h, then raising the temperature to 400~500 ℃ and holding for 4~12 h to ensure the formation of oxide crystal form.

[0010] Furthermore, the carrier is silicon dioxide: Step one, preprocessing, specifically involves: (1) Calcination to remove impurities: The temperature is 400~800 ℃ and the calcination time is 1~8 h; (2) Surface silanization treatment: The silicon oxide was immersed in a 1%~10% 3-aminopropyltriethoxysilane solution at room temperature for 1~48 h. In step three, the liquid-solid mass ratio of the impregnation solution to the carrier is 1:1 to 10:1, the impregnation temperature is controlled at 10 to 60°C, and the time is 12 to 24 hours. In step four, the calcination atmosphere is an air atmosphere, and the heating rate is 2~5 ℃ / min; the calcination method is segmented calcination, calcining at 300 ℃ for 2~6 h, then raising the temperature to 400~500 ℃ and holding for 4~12 h to ensure the formation of oxide crystal form.

[0011] A method for preparing a catalyst for the phosgenation production of 1,5-pentanediisocyanate is characterized by employing a support surface etching method; the support is one or a mixture of two of molecular sieve catalysts or alumina catalysts; and the Lewis acid catalyst is one or more of AlCl3, FeBr3, FeCl3, TiCl4, and ZnCl2. The support is a molecular sieve, and the specific steps of the preparation method are as follows: Step 1, Carrier Pretreatment: Eliminating surface adsorbates and providing a uniform substrate for etching. Step 2, Etching: For silicon-to-aluminum ratios greater than 20, use an alkaline etchant; for silicon-to-aluminum ratios of 10-20, use a fluoride etchant. Step 3: Loading Lewis acid catalysts onto the support surface: The carrier is alumina, and the specific steps of the preparation method are as follows: Step 1, carrier pretreatment: The alumina surface is calcined at high temperature to remove impurities; Step 2, Etching: Use an acidic etchant to dissolve the loose structure of the aluminum oxide surface layer; Step 3: Load a Lewis acid catalyst onto the support surface.

[0012] Furthermore, the support is a molecular sieve: Step one, the carrier pretreatment specifically involves: (1) Remove template agent from molecular sieve: calcine in air atmosphere for 4~12 h, calcine temperature for 200~600℃, heating rate for 2~4℃ / min; (2) The molecular sieve carrier was then washed with water to remove salt. The liquid-solid mass ratio of water to molecular sieve carrier was 5:1 to 50:1. The carrier was boiled at 100 °C for 1 to 5 h, and the process was repeated 3 to 6 times. (3) Finally, the molecular sieve catalyst on the support is dried and shaped. The drying temperature is 100~180 ℃ and the drying time is 2~24 h. Step two, etching, specifically: The molecular sieve support is placed in a 0.2 M NaOH solution at a liquid-to-solid ratio of 8:1 to 80:1 and pre-immersed at 50 °C for 30 to 180 min, followed by immersion at 70 °C for 2 to 5 h. During this process, samples are taken every 30 min to measure the Si content in the solution. 4+ concentration; Step 3: Loading a Lewis acid catalyst onto the support surface, specifically: (1) Pretreatment of impregnation solution: In the selection of precursors, anhydrous solids are selected for catalysts such as AlCl3, FeCl3, and ZnCl2; FeBr3 is dried under vacuum to remove water; and TiCl4 is diluted with anhydrous cyclohexane. The impregnation solution is one or more of anhydrous ethanol, cyclohexane, or dichloromethane. When single-component loading is used, the concentration of the impregnation solution is 0.05~0.5M. When two-component loading is used, it is prepared at a mass ratio of 1:1~3:1. (2) Place the etched dry carrier in the impregnation solution, control the liquid-solid mass ratio to be 2:1~12:1, seal it and place it in a constant temperature water bath; stir at 25~50 ℃ for 2~24 h. At the same time, for catalysts that are difficult to dissolve, use ultrasound assistance for 30 min to promote dissolution and penetration. (3) After the surface loading is completed, the solvent is removed by drying and activation to enhance the interaction between Lewis acid and support. Specifically, under nitrogen protection, the surface is dried at 60 °C for 2 h, at 80 °C for 2 h, and at 100 °C for 4 h; then the temperature is raised to 150~300 °C for 2~8 h for activation. Furthermore, the carrier is alumina: Step 1, carrier pretreatment, specifically: calcination temperature of 300~600 ℃, calcination time of 2~12 h; Subsequently, the surface hydroxyl content was adjusted by vacuum drying the supported catalyst at 100–160 °C under vacuum conditions of -0.15 MPa for 2–12 h, thereby adjusting the hydroxyl content on the catalyst surface to 0.5–1.2 mmol / g. Step two, etching, specifically: The alumina catalyst is placed in a 1 M dilute nitric acid / dilute hydrochloric acid solution at a liquid-to-solid ratio of 2:1 to 24:1 and immersed at 40 °C for 2–4 h. During this process, the Al concentration in the solution is measured every 20 min. 3+ concentration; Step 3: Load the Lewis acid catalyst onto the support surface, in the same manner as the method described above where the support is a molecular sieve; A mixed carrier was used, with molecular sieve and alumina in a mass ratio of 1:1 to 5:1; the etchant was first a 0.15M NaOH solution, followed by a 0.8M dilute hydrochloric acid / dilute nitric acid solution.

[0013] Furthermore, during the etching process, stirring is used to ensure uniform etching of the carrier surface; after etching, the surface is immediately washed three times with anhydrous ethanol and deionized water respectively until the filtrate is free of ions; then it is dried under vacuum at 80 °C for 4 h to avoid residual moisture that could lead to subsequent Lewis acid hydrolysis.

[0014] A method for applying a catalyst in the phosgenation process for producing 1,5-pentanediisocyanate, characterized by: adding 1,5- In the thermophotochemical reaction of glutaryl isocyanate, the addition amount is 1 wt%, the thermophotochemical reaction temperature is 80~155℃, and the reaction pressure is 150~220 kPa.

[0015] The principle of this invention: The support is composed of porous materials with high specific surface area and good thermal stability. These materials not only effectively disperse the active components but also provide sufficient contact interfaces during the reaction, thereby improving catalytic efficiency. The surface-supported Lewis acid catalyst mainly promotes the reactivity between phosgene and the 1,5-pentanediamine intermediate by adjusting the electronic structure. The synergistic effect between the support and the surface-supported Lewis acid catalyst significantly reduces the activation energy of the reaction, improving the selectivity and yield of the target product.

[0016] By constructing a hierarchical porous structure and high specific surface area, the distribution and wetting behavior of the gas and liquid phases on the catalyst surface are significantly improved. Its internal interconnected micropore-mesopore-macropore network facilitates the rapid diffusion of phosgene molecules to active sites, while simultaneously allowing liquid reactants to spread uniformly on the catalyst surface, forming a stable interfacial reaction region. This structural advantage effectively enhances the accessibility of active centers, enabling more catalytic sites to participate in the reaction, thereby significantly increasing the product formation rate per unit time. This type of catalyst can significantly reduce the activation energy required for the reaction, allowing the phosgenation reaction to proceed smoothly under relatively mild temperature and pressure conditions, avoiding the energy consumption problems caused by high-temperature driving in traditional processes. Taking Example 3 as an example, after using this type of catalyst, the reaction initiation temperature can be reduced by approximately 20-30 °C, the reaction cycle shortened by more than 30%, and the selectivity of the target product increased to over 95%, with a significant reduction in by-product content.

[0017] The beneficial effects of this invention are: The raw materials used are inexpensive, the preparation process is simple and safe, the reaction conditions are stable and highly reproducible, and it is easy to achieve large-scale industrial production. It solves the key technical problems of limited gas-liquid mass transfer, high energy consumption and many side reactions in traditional phosgenation processes, and provides a practical technical route for the green synthesis of 1,5-pentanediisocyanate. It has good engineering adaptability and can be extended to the phosgenation reaction process of other special isocyanates. It is expected to be widely used in the large-scale preparation of isocyanates required in high-performance coatings, adhesives and other fields, with significant economic benefits and broad industrial application prospects. Attached Figure Description

[0018] Figure 1 This is a scanning electron microscope image of the catalyst prepared in Example 3 of the present invention under a microscopic scale; Figure 2 This is a scanning electron microscope image of the catalyst prepared in Example 8 of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Step (1): Weigh 5 kg of activated carbon as the catalyst carrier and boil it in boiling water for 3 h, repeating the treatment 3 times; then transfer the activated carbon to a 20% HNO3 solution at 60 ℃ and stir for 4 h; then place the activated carbon with surface acid activation treatment in an oven and dry it at 120 ℃ for 12 h. After cooling to room temperature, sieve the activated carbon carrier through an 80-mesh sieve. Step (II): The sieved activated carbon carrier was placed in 50 L of 0.2 M aluminum nitrate impregnation solution and impregnated at 40 ℃ for 12 h. Then it was transferred to an oven and heated to 80 ℃ at a heating rate of 2 ℃ / min and dried for 4 h; then the temperature was raised to 110 ℃ and dried at a constant temperature for 8 h. Step (3): After the sample is dried, it is transferred to a calcination furnace and calcined at 300 °C in air atmosphere for 2 hours, and then calcined at 500 °C for 6 hours to obtain the catalyst.

[0021] Application of the catalyst: After the catalyst is cooled to room temperature, it is added to the phosgenation reaction system of 1,5-pentanediisocyanate at a mass ratio of 1 wt%. The reaction is carried out in a thermal phosgenation reactor, and the system pressure is controlled at 190 kPa.

[0022] Example 2 A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Step (1) is the same as in Example 1; Step (II): The sieved activated carbon carrier was placed in 50 L of 0.15 M ferric nitrate impregnation solution and impregnated at 40 ℃ for 12 h. Then it was transferred to an oven and heated to 80 ℃ at a heating rate of 2 ℃ / min and dried for 4 h; then the temperature was raised to 110 ℃ and dried at a constant temperature for 8 h. Step (3) is the same as in Example 1. Example 3

[0023] A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Step (1): Weigh 5 kg of silicon dioxide as a catalyst support. First, calcine the purchased silicon dioxide particles at 400 °C for 8 h. After cooling to room temperature, soak them in a 10% 3-aminopropyltriethoxysilane solution for 12 h. Then dry them at 60 °C, grind them, and pass them through an 80-mesh sieve.

[0024] Step (II): The sieved silica support was placed in 50 L of 0.2 M aluminum nitrate impregnation solution and impregnated at 60 ℃ for 24 h. Then it was transferred to an oven and heated to 80 ℃ at a heating rate of 2 ℃ / min, and dried for 4 h; then the temperature was raised to 120 ℃ and dried at a constant temperature for 8 h. Step (3): After the sample is dried, it is transferred to a calcination furnace and calcined at 400 °C in air atmosphere for 4 hours, and then calcined at 600 °C for 8 hours to obtain the catalyst.

[0025] Example 4 A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Step (1) is the same as in Example 3; Step (II): The sieved silica support was placed in 50 L of 0.15 M ferric nitrate impregnation solution and impregnated at 60 °C for 24 h. Then it was transferred to an oven and heated to 80 °C at a rate of 2 °C / min, and dried for 4 h; then the temperature was raised to 120 °C and dried at a constant temperature for another 8 h. Step (3) is the same as in Example 3. Example 5

[0026] A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Step (1): Weigh 5 kg of molecular sieve as a carrier. First, calcine the molecular sieve at 400 ℃ for 8 h in an air atmosphere. Then, mix the molecular sieve with water at a solid-liquid mass ratio of 1:30 and boil at 100 ℃ for 5 h. Repeat the treatment 3 times. Finally, dry and shape the molecular sieve carrier at 120 ℃ for 12 h. Step (2): The dried molecular sieve support was placed in a 0.2 M NaOH solution with a solid-liquid mass ratio of 1:30 and pre-soaked at 50 °C for 120 min. Then, the temperature was raised to 70 °C and soaked for another 5 h. After etching, it was immediately washed three times with anhydrous ethanol and deionized water, and then dried under vacuum at 80 °C for 4 h. Step (3): Prepare the impregnation solution according to the target loading of 10%. Under ice bath conditions, dissolve 50 g of TiCl4 in anhydrous cyclohexane (solvent to reagent volume ratio of 1:5) and stir continuously for 30 min. Then transfer the support to a three-necked flask, evacuate and replace the atmosphere with nitrogen three times. Slowly add the impregnation solution (liquid-solid ratio of 3:1) at 25 °C. Then raise the temperature to 40 °C and stir for 4 h. After stopping the stirring, let it stand at 25 °C for 6 h. Step (iv): Under nitrogen protection (flow rate 50 mL / min), the temperature was increased in a gradient of 60 °C for 2 h, 80 °C for 2 h, and 100 °C for 4 h, and then the temperature was increased to 200 °C for 8 h to obtain the catalyst. Example 6

[0027] A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Steps (I) and (II) are the same as in Example 5; Step (3): Prepare the impregnation solution according to the target loading of 10%. First, dry 50 g of FeBr3 at 120 °C under vacuum for 4 h. Then, under a nitrogen protective atmosphere, dissolve it in anhydrous cyclohexane (solvent to reagent volume ratio of 1:5) and stir continuously for 30 min. Then, transfer the support to a three-necked flask, evacuate and replace the atmosphere with nitrogen 3 times. Slowly add the impregnation solution (liquid-solid ratio of 3:1) at 25 °C. Then, sonicate at 40 kHz for 30 min, and then heat to 40 °C and stir for 4 h. After stopping stirring, let it stand at 25 °C for 6 h. Step (iv) is the same as in Example 5.

[0028] Example 7 A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Steps (I) and (II) are the same as in Example 5; Step (3): Prepare the impregnation solution according to the target loading of 10%. Weigh AlCl3 and FeCl3 separately, add anhydrous dichloromethane, and stir at 40 °C for 1 h. Then transfer the carrier to a three-necked flask, evacuate and replace the atmosphere with nitrogen three times. Add AlCl3 solution dropwise at 25 °C and stir at 25 °C for 2 h. Then add FeCl3 solution dropwise and continue stirring for 2 h. Then sonicate at 40 kHz for 30 min, and then heat to 40 °C and stir for 4 h. After stopping stirring, let it stand at 25 °C for 6 h. Step (iv) is the same as in Example 5.

[0029] Example 8 A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Step (1): Weigh 5 kg of alumina as a carrier. First, calcine the alumina at 450 °C for 4 h. Then, dehydrate and dry the carrier under vacuum at 110 °C for 5 h. After cooling to room temperature, pass it through an 80-mesh sieve. Step (2): The pretreated alumina support is placed in a 1.0 M HNO3 solution with a solid-liquid mass ratio of 1:12 and stirred at 40 °C for 2 h. After etching, it is immediately washed three times with anhydrous ethanol and deionized water respectively, and then dried under vacuum at 80 °C for 4 h. Steps (3) and (4) are the same as in Example 5.

[0030] Example 9 A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Steps (I) and (II) are the same as in Example 8; Step (iii) is the same as in Example 6; Step (iv) is the same as in Example 5.

[0031] Example 10 A method for preparing a catalyst for the phosgenation process to produce 1,5-pentanediisocyanate, comprising the following steps: Steps (I) and (II) are the same as in Example 8; Step (3) is the same as in Example 7; Step (iv) is the same as in Example 5.

[0032] Structural and performance characterization: Figure 1Scanning electron microscope (SEM) images of alumina particles loaded onto a silica support after surface modification in Example 3 are shown. It can be seen that the silica support exhibits a uniform overall morphology, a relatively consistent particle size distribution, and a noticeably smooth surface, indicating that surface impurities and irregular deposits were effectively removed during the initial heat treatment or chemical cleaning process. Notably, under high magnification, the support surface is not completely dense but rather contains a large number of nanoscale hierarchical porous structures, including mesopores (2–50 nm) and some micropores (<2 nm). These pores are interconnected, forming a well-developed specific surface area and good mass transfer channels. This hierarchical porous structure not only helps to increase the specific surface area of ​​the support and enhance the dispersion of active components but also promotes the diffusion of reactant molecules and the desorption of products during the catalytic reaction, thereby improving the overall catalytic efficiency. Furthermore, it can be clearly observed from the images that a large number of fine and uniformly distributed alumina nanoparticles have been successfully anchored on the original silica surface. These particles are uniform in size, with an average particle size of approximately 20–50 nm, and are tightly adhered to the silica substrate without significant agglomeration. This indicates that the loading process parameters were properly controlled, and the impregnation, drying, and calcination of the precursors achieved good dispersibility. Alumina, as a typical amphoteric metal oxide, possesses certain surface acid-base active sites. Its introduction can significantly modulate the surface chemical properties of the composite support, enhancing its adsorption and activation capabilities for specific reaction intermediates. Furthermore, a strong interfacial interaction may exist between alumina and silica, contributing to improved thermal stability and mechanical strength of the material, enabling it to maintain structural integrity even under high-temperature or harsh reaction conditions.

[0033] Figure 2 The image shows a scanning electron microscope (SEM) image at the microscale of the supported catalyst prepared by the etching method in Example 5 of this invention. It can be clearly observed from the image that the catalyst support is an alumina material with a regular flower-like structure and abundant pores. After etching, its surface forms a rich micro- and nano-scale porous structure, significantly increasing the specific surface area and the exposure of active sites. On the surface of this support, the Lewis acid catalyst is uniformly distributed in a crystalline particulate form without obvious agglomeration, indicating that the etching process effectively improves the catalyst's dispersibility. This highly dispersed crystalline structure helps to improve the utilization rate of active sites during the reaction process and enhances its adsorption and activation ability for target reactants.

[0034] Table 1 lists the theoretically calculated reaction temperatures required for the 10 catalysts in the examples to participate in the target thermophosgenesis reaction (i.e., the stepwise decomposition of carbamoyl chloride to 1,5-pentanediisocyanate and hydrogen chloride) under 190 kPa conditions. This calculation is based on the core principle that catalysts can lower the activation energy (Ea), thereby reducing the reaction temperature. Under catalyst-free conditions, the required reaction temperature is 148 °C. By comprehensively considering the catalyst type and its Lewis acid strength, as well as the interaction between the support and the active component, their impact on the degree of activation energy reduction is evaluated. Furthermore, the Arrhenius equation is used to establish a quantitative relationship between the activation energy and the reaction temperature, thereby calculating the theoretical reaction temperature under each catalyst condition.

[0035]

[0036] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0037] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A catalyst for the phosgenation process in the production of 1,5-pentanediisocyanate, characterized in that: Supported catalysts are composed of a support and a surface Lewis acid catalyst. The support is one or more of activated carbon, alumina, silica, or molecular sieve catalyst. The Lewis acid catalyst is one or a mixture of two or more of AlCl3, FeBr3, FeCl3, TiCl4, ZnCl2, Al2O3, and Fe2O3.

2. The catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 1, characterized in that, The molecular sieve catalyst is one or a mixture of two or more of SAPO-11, ZSM-5, aluminum phosphate molecular sieve catalyst, TS molecular sieve catalyst, MCM series molecular sieve catalyst, and SBA molecular sieve catalyst.

3. The catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 1, characterized in that, The activated carbon has a particle size of 0.15~0.18 mm and a surface pore size of 50 nm~1 μm; The alumina has a particle size of 0.15~0.18 mm and a surface pore size of 1 μm~20 μm; The silica has a particle size of 0.15~0.18 mm and a surface pore size of 0.2 nm~200 nm; The molecular sieve has a particle size of 0.15~0.18 mm and a surface pore size of 0.2 nm~2 nm.

4. The method for preparing the catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 1, characterized in that: The impregnation method is used, with the support being one or a mixture of activated carbon and silicon dioxide; the Lewis acid catalyst is Al2O3 or Fe2O3. The carrier is activated carbon, and the specific steps of the preparation method are as follows: Step 1, Pretreatment: First, the activated carbon is washed with water to remove ash, then soaked in nitric acid solution for surface acid modification, and finally dried and activated to form a Lewis acid active phase on the surface. Step 2, Grinding and Sieving: The mesh size of the sieve is 80-100 mesh; Step 3, Impregnation: Aluminum nitrate and ferric nitrate are selected as precursors to prepare the impregnation solution. During the impregnation process, the solution is stirred for 30 minutes every 4 hours. Step four, drying and calcination: the loading of the active component on the support surface in the obtained catalyst is 2% to 20%; The carrier is silicon dioxide, and the specific steps of the preparation method are as follows: Step 1, Pretreatment: First, the silicon oxide is calcined to remove impurities, and then the surface is silanized. Steps two, three, and four are the same as the corresponding steps when the carrier is activated carbon; A mixed carrier is used, in which activated carbon and silicon dioxide are mixed at a mass ratio of 1:1 to 3:

1. In the preparation method, the pretreatment in step one is carried out according to the method of the corresponding single carrier, and steps two, three and four are the same as the corresponding steps when the carrier is activated carbon or silicon dioxide.

5. The method for preparing the catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 4, characterized in that, The carrier is activated carbon. Step one, preprocessing, specifically involves: (1) Boil the activated carbon carrier in process water for 1-5 hours, and repeat the water washing and ash removal treatment 1-5 times. (2) Soak in HNO3 solution at 60~80 ℃ and 10%~40% concentration for 2~6 h to perform surface acid modification; (3) Place the surface acid-modified activated carbon carrier in an oven and dry it at 100 ℃~160 ℃ for 6~24 h to activate it; In step three, the liquid-solid mass ratio of the impregnation solution to the carrier is 1:1 to 10:1, the impregnation temperature is controlled at 10 to 60 °C, and the time is 12 to 24 h; In step four, the calcination atmosphere is an air atmosphere, and the heating rate is 2~5 ℃ / min; the calcination method is segmented calcination, calcining at 300 ℃ for 2~6 h, then raising the temperature to 400~500 ℃ and holding for 4~12 h to ensure the formation of oxide crystal form.

6. The method for preparing the catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 4, characterized in that: The carrier is silicon dioxide: Step one, preprocessing, specifically involves: (1) Calcination to remove impurities: The temperature is 400~800 ℃ and the calcination time is 1~8 h; (2) Surface silanization treatment: The silicon oxide was immersed in a 1%~10% 3-aminopropyltriethoxysilane solution at room temperature for 1~48 h. In step three, the liquid-solid mass ratio of the impregnation solution to the carrier is 1:1 to 10:1, the impregnation temperature is controlled at 10 to 60 °C, and the time is 12 to 24 h; In step four, the calcination atmosphere is an air atmosphere, and the heating rate is 2~5 ℃ / min; the calcination method is segmented calcination, calcining at 300 ℃ for 2~6 h, then raising the temperature to 400~500 ℃ and holding for 4~12 h to ensure the formation of oxide crystal form.

7. The method for preparing the catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 1, characterized in that: The method employs a carrier surface etching method; the carrier is one or a mixture of two of molecular sieve catalysts or alumina catalysts; the Lewis acid catalyst is one or more of AlCl3, FeBr3, FeCl3, TiCl4, and ZnCl2; The support is a molecular sieve, and the specific steps of the preparation method are as follows: Step 1, Carrier Pretreatment: Eliminating surface adsorbates and providing a uniform substrate for etching. Step 2, Etching: For silicon-to-aluminum ratios greater than 20, use an alkaline etchant; for silicon-to-aluminum ratios of 10-20, use a fluoride etchant. Step 3: Loading Lewis acid catalysts onto the support surface: The carrier is alumina, and the specific steps of the preparation method are as follows: Step 1, carrier pretreatment: The alumina surface is calcined at high temperature to remove impurities; Step 2, Etching: Use an acidic etchant to dissolve the loose structure of the aluminum oxide surface layer; Step 3: Load a Lewis acid catalyst onto the support surface.

8. The method for preparing the catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 7, characterized in that: The carrier is a molecular sieve. Step one, the carrier pretreatment specifically involves: (1) Remove template agent from molecular sieve: calcine in air atmosphere for 4~12 h, calcine temperature is 200~600 ℃, heating rate is 2~4 ℃ / min; (2) The molecular sieve carrier was then washed with water to remove salt. The liquid-solid mass ratio of water to molecular sieve carrier was 5:1 to 50:

1. The carrier was boiled at 100 °C for 1 to 5 h, and the process was repeated 3 to 6 times. (3) Finally, the molecular sieve catalyst on the support is dried and shaped. The drying temperature is 100~180 ℃ and the drying time is 2~24 h. Step two, etching, specifically: The molecular sieve support is placed in a 0.2 M NaOH solution at a liquid-to-solid ratio of 8:1 to 80:1 and pre-immersed at 50 °C for 30 to 180 min, followed by immersion at 70 °C for 2 to 5 h. During this process, samples are taken every 30 min to measure the Si content in the solution. 4+ concentration; Step 3: Loading a Lewis acid catalyst onto the support surface, specifically: (1) Pretreatment of the impregnation solution In the selection of precursors, anhydrous solids are used for catalysts AlCl3, FeCl3, and ZnCl2; FeBr3 is dehydrated by vacuum drying; and TiCl4 is diluted with anhydrous cyclohexane. The impregnation solution is one or more of anhydrous ethanol, cyclohexane, or dichloromethane. For single-component loading, the impregnation solution concentration is 0.05~0.5 M; for two-component loading, it is prepared at a mass ratio of 1:1~3:

1. (2) Place the etched dry carrier in the impregnation solution, control the liquid-solid mass ratio to be 2:1~12:1, seal it and place it in a constant temperature water bath; stir at 25~50 ℃ for 2~24 h. At the same time, for catalysts that are difficult to dissolve, use ultrasound assistance for 30 min to promote dissolution and penetration. (3) After the surface loading is completed, the solvent is removed by drying and activation to enhance the interaction between Lewis acid and support. Specifically, under nitrogen protection, the surface is dried at 60 °C for 2 h, at 80 °C for 2 h, and at 100 °C for 4 h; then the temperature is raised to 150~300 °C for 2~8 h for activation. The carrier is alumina: Step 1, carrier pretreatment, specifically: calcination temperature of 300~600 ℃, calcination time of 2~12 h; Subsequently, the surface hydroxyl content was adjusted by vacuum drying the supported catalyst at 100–160 °C under vacuum conditions of -0.15 MPa for 2–12 h, thereby adjusting the hydroxyl content on the catalyst surface to 0.5–1.2 mmol / g. Step two, etching, specifically: The alumina catalyst is placed in a 1 M dilute nitric acid / dilute hydrochloric acid solution at a liquid-to-solid ratio of 2:1 to 24:1 and immersed at 40 °C for 2–4 h. During this process, the Al concentration in the solution is measured every 20 min. 3+ concentration; Step 3: Load the Lewis acid catalyst onto the support surface, in the same manner as the method described above where the support is a molecular sieve; A mixed carrier is used, with molecular sieve and alumina in a mass ratio of 1:1 to 5:1; The etching agent was first a 0.15 M NaOH solution, followed by a 0.8 M dilute hydrochloric acid / dilute nitric acid solution.

9. The method for preparing the catalyst for the phosgenation production of 1,5-pentanediisocyanate according to claim 7 or 8, characterized in that: During the etching process, stirring is used to ensure uniform etching of the carrier surface. After etching, the carrier is immediately washed three times with anhydrous ethanol and deionized water until the filtrate is free of ions. Then, it is dried under vacuum at 80 °C for 4 h to avoid residual moisture that could lead to subsequent Lewis acid hydrolysis.

10. A method of using the catalyst for the phosgenation process for producing 1,5-pentanediisocyanate as described in any one of claims 1-9, characterized in that: During the thermophotochemical reaction of 1,5-pentanediisocyanate, the addition amount is 1 wt%, the thermophotochemical reaction temperature is 80~155 ℃, and the reaction pressure is 150~220 kPa.

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