Preparation method and application of Ni3P catalyst for preparing succinic anhydride by hydrogenation of maleic anhydride

Abstract

The present invention discloses a preparation method and application of a Ni3P catalyst for preparing succinic anhydride by hydrogenating maleic anhydride, and belongs to the field of catalyst preparation and hydrogenation catalysis. The catalyst is composed of a carrier and an active center, and is prepared by sedimentation precipitation, phosphating and reduction steps. After a slow-release agent as a precipitant and a complexing agent wrapping the nickel precursor, the catalyst produces smaller nickel particles after phosphating, so that the active components are evenly distributed, the reaction activity is high, and the catalyst life is long. The preparation method adopted by the present invention makes the catalyst particles smaller, the preparation scheme is more environmentally friendly and efficient, the range of complexing agent selection is wider, the conditions are mild, and the catalyst raw material price is low. The present invention can achieve a yield of succinic anhydride of more than 99.5% after reacting for 1 hour at 1MPa H2 and 120°C, and has good industrial application prospects.

Description

Technical Field

[0001] The invention belongs to the fields of catalyst technology and industrial catalysis, and relates to a preparation method and application of a Ni3P catalyst for preparing succinic anhydride by hydrogenating maleic anhydride. Background Art

[0002] Maleic anhydride is abbreviated as maleic anhydride, also known as maleic anhydride. In my country, it is one of the three major acid anhydrides along with acetic anhydride and phthalic anhydride. It is a white needle-shaped crystal, easily soluble in water to form maleic acid, easily sublimated, and soluble in alcohol, ether and acetone. It is mainly used in the production of unsaturated polyester resins, lubricant additives, pharmaceutical intermediates, organic chemical intermediates, food additives, agricultural chemicals, thermosetting resins, coatings, inks and surfactants.

[0003] Succinic anhydride is an organic compound that can be produced by hydrogenation of maleic anhydride. Its main uses are:

[0004] 1. As an important raw material for organic synthesis: Succinic anhydride is often used in organic chemical reactions and can be used to prepare a variety of organic compounds, such as esters, amides, acylation reagents, etc.

[0005] 2. Used in the preparation of dyes and pigments: Succinic anhydride can be used to synthesize dyes and pigments. By reacting with other compounds, dyes and pigments with specific colors can be obtained.

[0006] 3. Used in the preparation of plastics and polymers: Succinic anhydride can undergo polymerization reactions with other compounds to obtain plastic polymers such as polysuccinate, which have excellent physical and chemical properties and can be used to make various plastic products.

[0007] 4. Used in the production of coatings and inks: Succinic anhydride can be used as a component in coatings and inks to provide specific properties, such as increasing the adhesion, durability and gloss of coatings and inks.

[0008] 5. Used in the preparation of medicines and pesticides: Succinic anhydride can be used to synthesize raw materials or intermediates of some medicines and pesticides, and has a wide range of applications.

[0009] The current method for producing succinic anhydride primarily relies on direct catalytic hydrogenation of maleic anhydride. The publication "Production and Application of Succinic Anhydride" states that maleic anhydride can be hydrogenated in the presence of a palladium-alumina (or copper molybdate) catalyst at 160°C and 5.8 MPa to produce succinic anhydride, achieving a conversion rate of 98.8% and a selectivity of 100%. This method utilizes the principle of efficient hydrogenation using precious metal catalysts, but it also involves high reaction pressures and temperatures, placing stringent equipment requirements. Furthermore, the molybdenum salt used can be lost, making product separation difficult. Furthermore, the precious metal catalyst is expensive.

[0010] The current preferred Ni3P synthesis scheme (CN116351446A) associated with succinic anhydride, although also can be used for the hydrogenation reaction of maleic anhydride, but conversion rate is lower, catalyst is unstable, and this scheme needs manual operation when adding catalyst precursor, is unfavorable for industrialization, in order to solve these problems, improve the conversion efficiency of catalyst simultaneously, we have improved this synthesis scheme, make it more conducive to industrialization. Selected non-precious metal catalyst Ni3P-based catalyst as active center, with aluminum oxide as carrier, Ni3P catalyst has class Pt property, has good catalytic activity, Al2O3 has good thermal stability. For making nickel particle deposition precipitation more uniform, we adopted and added the precipitation agent with slow-release effect, and verified the effect of different slow-release agents, the use of precipitation agent makes active center distribution more uniform, follow-up, for more convenient phosphating step, we use complexing agent to optimize phosphating step, make this catalyst reaction activity obtain greatly improved, and reduce the process of manual operation, be conducive to industrialization promotion. This method is a new route that meets sustainable development, has subsequent research significance and industrialization prospect. Summary of the Invention

[0011] The present invention provides a catalyst for synthesizing Ni3P and exhibiting hydrogenation activity, as well as a preparation method and application thereof. Considering the high cost of noble metal catalysts, which preclude industrial production, the Ni3P / Al2O3 catalyst prepared by this method has low production cost and high hydrogenation efficiency. The reaction system is green and efficient. The use of a green sustained-release agent reduces environmental pollution. The use of a complexing agent not only improves reaction activity but also reduces manual operation processes, resulting in greater efficiency. This method represents a new approach consistent with sustainable development and has significant research implications and promising industrial applications.

[0012] The technical solutions of the present invention are as follows:

[0013] A method for preparing a Ni3P catalyst for hydrogenating maleic anhydride to prepare succinic anhydride, comprising the following steps:

[0014] (1) preparing a Ni(NO3)2 aqueous solution with a concentration of 0.01-0.05 mol / L, adding a γ-Al2O3 carrier to the Ni(NO3)2 aqueous solution, and stirring and dispersing the solution at a temperature of 50-90°C for 2-5 hours to form a suspension A; wherein the loading amount of the γ-Al2O3 carrier is between 5-25 wt.%;

[0015] (2) Slowly heat the suspension A to 90-95°C, then weigh a precipitant for slow release to prepare a solution B with a concentration of 0.05-0.5 mol / L and a pH of 8-11, and drip it into the suspension A at a rate of 0.05 mL / min until all the solution is added. The reaction is continued for 2-8 hours. After the reaction is completed, filter and wash the filtrate to neutrality, and dry it in an oven at 90-120°C overnight to obtain a light green catalyst precursor.

[0016] (3) The catalyst precursor is added to an acetic acid-sodium acetate buffer solution with a pH value of 4-7, and then a complexing agent is added, wherein the mass ratio of the complexing agent to the catalyst precursor is 1.5:1, and ultrasonication is carried out for 15 minutes; the solution is slowly heated to 90-95°C; a prepared NaH2PO2 solution with a concentration of 0.05-2.5 mol / L is added dropwise to the solution, and the mixture is stirred continuously for 4-6 hours; after the reaction is completed, the catalyst solid obtained after filtration and washing is dried in an oven at 90-120°C overnight, and then heat-treated at 300-600°C under H2 atmosphere for 1-4 hours, and then cooled and annealed to obtain a Ni3P / Al2O3 catalyst.

[0017] After adding NaH2PO2, the color of the reaction solution will gradually turn black and gas will be generated. When no more gas is generated, it proves that the reaction is complete.

[0018] The precipitating agents are ammonia water, urea, NaOH and triethanolamine.

[0019] The complexing agents are glucose, citric acid and dopamine.

[0020] In step (1), the stirring is carried out under oil bath conditions.

[0021] In step (2), the mixture is dried for 8-10 hours.

[0022] The presence of a precipitant and complexing agent in the supported Ni3P / Al2O3 catalyst results in smaller catalyst particles and a more uniform distribution of active components. Maleic anhydride is catalytically hydrogenated to succinic anhydride in an H2 atmosphere. The key to efficient hydrogenation is the selection of different precipitants, each with its own slow-release rate, resulting in a highly dispersed catalyst precursor. Figure 1 )

[0023] The catalyst obtained by the above preparation method is used for hydrogenating maleic anhydride to produce succinic anhydride. The specific application method is as follows:

[0024] (1) Using a 100 mL reactor, 0.5-2 g of the catalyst and 10-20 mL of a prepared dioxane solution containing maleic anhydride were added to the reactor system, wherein the maleic anhydride concentration was 5-15 wt.%;

[0025] (2) React at 90-150°C and a pressure of 0.1-3 MPa for 0.1-3 hours, with an upper temperature limit of 350°C and an upper pressure limit of 10 MPa.

[0026] Beneficial effects of the present invention:

[0027] 1. The catalyst prepared by the present invention utilizes the principle that the precipitant slowly releases hydroxide, which slows down the reaction rate of the nickel precursor, thereby obtaining active centers with smaller particles and higher dispersion.

[0028] 2. The catalyst prepared by the present invention utilizes a complexing agent to complex with the metal on the catalyst surface, thereby reducing the phosphating rate and avoiding its violent reaction, thereby making its active center more dispersed, and the amount of complexing agent used is relatively small.

[0029] 3. The catalyst prepared by the present invention optimizes the synthesis steps of Ni3P and is more conducive to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the XRD pattern of the effects of different precipitants on Ni3P / Al2O3 catalyst.

[0031] Figure 2 This is the XRD pattern of the effect of different complexing agents on Ni3P / Al2O3 catalyst. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0033] Example 1

[0034] The catalyst was synthesized using urea as a precipitant and glucose as a complexing agent. The method was as follows: 2.6 g of Ni(NO₃)₂·6H₂O was dissolved in 250 mL of deionized water and heated to 90°C with stirring. 2.1 g of γ-Al₂O₃ was dispersed into the solution, which was then stirred and dispersed at 90°C for 2–3 hours before heating was stopped. 7.6 g of urea was diluted to 50 mL and slowly added dropwise to the solution at room temperature until the urea had completely reacted. The solution was filtered, washed with deionized water until neutral, and dried in a 120°C oven overnight to obtain a nickel-containing precursor. Then, 100 mL of acetic acid-sodium acetate buffer solution (pH 5.5) was prepared, the previously prepared nickel-containing precursor was added, 2 g of glucose was weighed, and the solution was sonicated for 15 minutes. NaH₂PO₄·H₂O was slowly added dropwise, and the solution was heated to 90°C with stirring. After the reaction stops, the product is filtered, washed with deionized water until neutral, dried in a constant temperature oven overnight, and finally heat treated at 400°C in H2 for 2h to prepare the target catalyst. Figure 1 Shown is the XRD of the catalyst Figure 1 , and its hydrogenation performance is shown in Table 1.

[0035] Example 2

[0036] The catalyst was synthesized using aqueous ammonia as a precipitant and glucose as a complexing agent, specifically as follows: 0.2 g aqueous ammonia was weighed and diluted to 50 ml to replace 7.6 g urea diluted to 50 ml in Example 1. Figure 1 Shown is the XRD pattern of the catalyst.

[0037] Example 3

[0038] The catalyst was synthesized using triethanolamine as a precipitant and glucose as a complexing agent, specifically as follows: 0.2 g of triethanolamine was weighed and diluted to 50 ml to replace 7.6 g of urea diluted to 50 ml in Example 1. Figure 1 Shown is the XRD pattern of the catalyst.

[0039] Example 4

[0040] The catalyst was synthesized using NaOH as a precipitant and glucose as a complexing agent, specifically as follows: 0.2 g of NaOH was weighed and diluted to 50 ml to replace 7.6 g of glucose in Example 1. Figure 1 Shown is the XRD pattern of the catalyst.

[0041] Example 5

[0042] The catalyst was synthesized using ammonia water as a precipitant and dopamine as a complexing agent, specifically as follows: 2 g of dopamine was weighed to replace 2 g of glucose in Example 2. Figure 2 Shown is the XRD pattern of the catalyst.

[0043] Example 6

[0044] The catalyst was used as follows: The catalyst's reactivity was evaluated in an autoclave reactor. 0.1 g of catalyst, 1 g of maleic anhydride, and 10 mL of dioxane were weighed and reacted in an autoclave at 120-150°C and 1 MPa for a specified time. After the reaction, the sample was analyzed by gas chromatography. The reaction results and catalytic performance of Examples 1-6 are shown in Table 1.

[0045] Table 1 Catalytic hydrogenation performance of catalysts prepared by different methods

[0046] catalyst Pressure (MPa) Reaction time (h) Temperature (℃) Conversion rate (%) Selectivity (%) <![CDATA[Urea-Ni3P / Al2O3]]> 1 1 120 70.2 99.5 <![CDATA[Ammonia - Ni3P / Al2O3]]> 1 1 120 99.6 99.5 <![CDATA[Triethanolamine-Ni3P / Al2O3]]> 1 1.5 150 75.6 99.4 <![CDATA[NaOH-Ni3P / Al2O3]]> 1 1 120 72.9 99.6 <![CDATA[DA-Ni3P / Al2O3]]> 1 1 120 93.5 97.1

[0047] Comparative Example 1

[0048] The catalyst was synthesized without the addition of a complexing agent. The specific steps were as follows: 2 g of water was weighed instead of the 2 g of glucose in Example 1. The prepared catalyst was designated H2O-Ni3P / Al2O3. 0.1 g of the catalyst, 1 g of maleic anhydride, and 10 mL of dioxane were weighed and reacted at 120°C and 1 MPa for a specified time. After the reaction, the sample was analyzed by gas chromatography. The reaction results are detailed in Table 2.

[0049] Table 2 Effect of the presence or absence of complexing agent on the reaction results

[0050] catalyst Pressure (MPa) Reaction time (h) Temperature (℃) Conversion rate (%) Selectivity (%) <![CDATA[H2O-Ni3P / Al2O3]]> 1 1 120 56.6 98.2 <![CDATA[Ammonia water-Ni3P / Al2O3]]> 1 1 120 99.6 99.5

[0051] Figure 1 This demonstrates that Ni3P can be prepared using any of these methods. The catalyst particle size and dispersion vary with the different precipitants. The figure shows that the catalyst particles produced using ammonia as the precipitant are smaller. Table 1 also shows that the catalyst produced using ammonia as the precipitant achieves the best reaction results. This is because ammonia releases hydroxide at a moderate rate, effectively slowing the reaction rate of the nickel precursor, resulting in smaller, more dispersed active centers.

[0052] Figure 2 This method demonstrates that Ni3P can be prepared using all methods. The catalyst particles prepared using different complexing agents exhibit different sizes and dispersities. Comparison with Example 1 demonstrates that the introduction of a complexing agent enhances the catalyst's reactivity, simplifies the preparation process, and demonstrates promising industrial application prospects. This is because the addition of a complexing agent complexes with the metal on the catalyst surface, slowing the Ni phosphating rate and preventing its violent reaction, thereby further dispersing its active centers. Furthermore, the amount of complexing agent used is relatively low.

[0053] It should be pointed out in the present invention that the catalyst is used to carry out hydrogenation reaction on maleic anhydride, the main product of which is succinic anhydride, the reaction temperature is low and the efficiency is high.

[0054] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for preparing a Ni3P catalyst for preparing succinic anhydride by hydrogenation of maleic anhydride, characterized in that: Here are the steps: (1) preparing a Ni(NO3)2 aqueous solution with a concentration of 0.01-0.05 mol / L, adding a γ-Al2O3 carrier to the Ni(NO3)2 aqueous solution, and stirring and dispersing the solution at a temperature of 50-90°C for 2-5 hours to form a suspension A; wherein the loading amount of the γ-Al2O3 carrier is between 5-25 wt.%; (2) Slowly heat the suspension A to 90-95°C, then weigh a precipitant for slow release to prepare a solution B with a concentration of 0.05-0.5 mol / L and a pH of 8-11, and drip it into the suspension A at a rate of 0.05 mL / min until all the solution is added. The reaction is continued for 2-8 hours. After the reaction is completed, filter and wash the filtrate to neutrality, and dry it in an oven at 90-120°C overnight to obtain a light green catalyst precursor. The precipitant is ammonia water; (3) The catalyst precursor is added to an acetic acid-sodium acetate buffer solution with a pH value of 4-7, and then a complexing agent is added, wherein the mass ratio of the complexing agent to the catalyst precursor is 1.5:1, and ultrasonication is carried out for 15 minutes; the solution is slowly heated to 90-95°C; a prepared NaH2PO2 solution with a concentration of 0.05-2.5 mol / L is added dropwise to the solution, and the mixture is stirred continuously for 4-6 hours; after the reaction is completed, the catalyst solid obtained after filtration and washing is dried in an oven at 90-120°C overnight, and then heat-treated at 300-600°C under H2 atmosphere for 1-4 hours, and then cooled and annealed to obtain a Ni3P / Al2O3 catalyst.

2. The preparation method according to claim 1, characterized in that The complexing agents are glucose, citric acid and dopamine.

3. The preparation method according to claim 1, characterized in that In step (1), the stirring is carried out under oil bath conditions.

4. The preparation method according to claim 1, characterized in that In step (2), the mixture is dried for 8-10 hours.

5. Use of the catalyst obtained by the preparation method according to any one of claims 1 to 4, wherein the catalyst is used for hydrogenating maleic anhydride to prepare succinic anhydride, characterized in that: The details are as follows: The reaction is carried out in a reactor, a catalyst is placed in the reactor, and a dioxane solution of maleic anhydride with a maleic anhydride concentration of 5-15 wt.% is added to the reactor system; the reaction is carried out at 90-150° C. and a pressure of 0.1-3 MPa for 0.1-3 hours.

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