A bimetallic catalyst for preparing o-phthalaldehyde by hydrogenation of dimethyl phthalate and a preparation method thereof

Abstract

The application discloses a bimetallic catalyst for preparing o-phthalaldehyde by dimethyl phthalate hydrogenation and a preparation method thereof, and belongs to the field of catalyst preparation and application. The Ni-Fe / Al2O3-ZrO2 catalyst loaded with nickel and iron bimetal is prepared by taking alumina and zirconium dioxide as carriers, wherein n(Ni):n(Fe):n(Al):n(Zr) = 0.1:0.05:2:1. The Ni-Fe / Al2O3-ZrO2 catalyst is prepared by first preparing a Ni-Fe / Al2O3-ZrO2 catalyst precursor and then carrying out a reduction reaction in a hydrogen atmosphere. The Ni-Fe / Al2O3-ZrO2 catalyst of the application will not be deactivated due to carbon deposition and metal sintering in the high-temperature hydrogenation process, prolongs the service life of the catalyst, promotes the reaction of preparing o-phthalaldehyde by dimethyl phthalate hydrogenation, and has great competitive advantages.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde and its preparation method. Background Technology

[0002] Dimethyl phthalate has the molecular formula C 10 H 10 O4 is a colorless, transparent, slightly yellow oily liquid with a slight aromatic odor. It is miscible with common organic solvents such as ethanol and ether, but insoluble in water and petroleum ether.

[0003] Dimethyl phthalate (DMP) is a plasticizer with strong solubility in various resins. It is compatible with many cellulose resins, rubbers, and vinyl resins, and exhibits good film-forming, adhesive, and waterproof properties. It is often used in combination with diethyl phthalate in the production of cellulose acetate films, varnishes, transparent paper, and molding powders. Small amounts are used in the production of nitrocellulose and as a plasticizer for nitrile rubber. DMP is also used as a solvent in mosquito repellent oils (crude oil), polyvinyl fluoride coatings, methyl ethyl ketone peroxide, and DDT. Because DMP is not chemically bonded to the main structure of plastics, it is continuously released into the surrounding environment during the preparation and use of these products, polluting the air, water, and soil. It accumulates and proliferates through the food chain of ecosystems, further entering organisms. DMP is one of the most common phthalates (PAEs) in aquatic environments and is one of the six priority controlled toxic pollutants designated by the U.S. Environmental Protection Agency. It is also included in China's blacklist of priority controlled pollutants.

[0004] Phthalate, with the molecular formula C8H6O2, is sensitive to light and air and volatilizes with water vapor. It is soluble in water, ethanol, ether, and organic solvents, slightly soluble in petroleum ether, and is irritating. It is mainly used in the chemical analysis of amine alkaloids, in the fluorescence determination of primary amines and peptide bond decomposition products, and in the synthesis of pharmaceutical intermediates and fluorescent reagents, such as in pre-column HPLC for separating amino acid derivatives and flow cytometry for measuring thiol groups in proteins.

[0005] Glutaraldehyde, a traditional disinfectant for medical devices, is a broad-spectrum and highly effective disinfectant that can kill vegetative bacteria, some bacterial spores, fungi, and viruses (including hepatitis A, hepatitis B, and HIV). However, glutaraldehyde becomes ineffective after being activated by sodium bicarbonate and left at room temperature for one week. With the widespread use of glutaraldehyde, it has been found to have significant mucosal toxicity and skin irritation, as well as moderate toxicity and mucosal mucosal effects. Orthophthalaldehyde (OPA), as a novel chemical disinfectant, is chemically stable, requires low concentrations, is non-irritating to skin and mucous membranes, has no unpleasant odor, and possesses the excellent microbial killing ability and low corrosiveness of glutaraldehyde. It can replace glutaraldehyde in the widespread application of medical device disinfection. Therefore, continuous research into new catalysts, expanding the production capacity of orthophthalaldehyde equipment, and increasing the concentration of orthophthalaldehyde products have promising development prospects.

[0006] Chinese patent CN114524718A discloses a method for preparing high-purity phthalaldehyde from phthalic acid diester. This patented method first hydrogenates phthalic acid diester to obtain phthalimide, and then oxidizes phthalimide to generate the target product phthalaldehyde. The process is time-consuming and labor-intensive, increasing production costs. Furthermore, during the oxidation to phthalaldehyde, byproducts are easily generated due to peroxidation, which affects the product yield. In addition, during the extraction and recrystallization processes, phthalimide, the added solvents, and additives all affect the purity of the target product. Summary of the Invention

[0007] The purpose of this invention is to develop a bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde and a method for its preparation.

[0008] The present invention provides a Ni-Fe / Al2O3-ZrO2 catalyst for the hydrogenation of dimethyl phthalate to prepare phthalaldehyde; wherein the molar ratio of each metal element is n(Ni):n(Fe):n(Al):n(Zr)=0.1:0.05:2:1.

[0009] Another aspect of the present invention provides a method for preparing a Ni-Fe / Al2O3-ZrO2 catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde, the steps of which are as follows:

[0010] (1) Weigh a certain amount of aluminum nitrate and zirconium dioxide into a mortar, grind them thoroughly for 15 min, transfer them to an oven to dry, place them in a muffle furnace, and calcine them under certain conditions to prepare Al2O3-ZrO2 support.

[0011] The formula is: n(Ni):n(Fe):n(Al):n(Zr) = 0.1:0.05:2:1. The drying temperature is 30-120℃, the drying time is 8-48h, the calcination temperature is 200-600℃, and the calcination time is 2-12h.

[0012] (2) Weigh a certain amount of ferric nitrate, nickel nitrate and the Al2O3-ZrO2 support prepared in step (1) above and place them in a beaker. Mix and stir evenly at room temperature. Put them into the polytetrafluoroethylene canister of the ball mill for mechanical ball milling. After the ball milling is completed, take them out of the ball mill and separate them from the agate balls. Place them in an oven to dry and transfer them to a muffle furnace. Calcinate them under certain conditions to prepare Ni-Fe / Al2O3-ZrO2 catalyst precursor.

[0013] The agate balls have a diameter of 10mm, a ball-to-material ratio of 3, a ball milling time of 60min, a drying temperature of 30-120℃, a drying time of 10-48h, a calcination temperature of 300-800℃, and a calcination time of 2-12h.

[0014] (3) The above-mentioned Ni-Fe / Al2O3-ZrO2 catalyst precursor was placed in a tube furnace and reduced at a certain temperature for a certain time in a hydrogen atmosphere to prepare the Ni-Fe / Al2O3-ZrO2 catalyst.

[0015] The hydrogen flow rate is 80 mL / min, the reduction reaction temperature is 300-800℃, and the reduction time is 2-12 h.

[0016] Another aspect of this invention provides an application of the aforementioned bimetallic catalyst, Ni-Fe / Al2O3-ZrO2. The application involves loading the catalyst into a fixed-bed reactor, adding dimethyl phthalate, and introducing hydrogen gas to initiate the reaction at a flow rate of 80 mL / min. The reaction temperature is 300-380 °C, and the pressure is 0.1-2 MPa. After the reaction is complete, the reaction is analyzed by gas chromatography.

[0017] The amount of Ni-Fe / Al2O3-ZrO2 catalyst used was 0.3 g; the volumetric flow rate of dimethyl phthalate was 0.1 mL / min.

[0018] The advantages of this invention are:

[0019] (1) Ni, as an active center, can catalyze the hydrogenation of dimethyl phthalate, reduce the reaction temperature of dimethyl phthalate hydrogenation, and improve the reaction activity of the catalyst and the selectivity of phthalaldehyde. Adding Fe as an auxiliary agent allows Ni to be better dispersed on the support surface, and Fe can better adsorb dimethyl phthalate on the support surface, thereby improving the utilization rate of the catalyst and thus improving the conversion rate and selectivity of the reactants.

[0020] (2) Al2O3 has good mechanical strength, good thermal stability, suitable pore structure and large surface area, and is a commonly used support for metal Ni catalysts in industry; ZrO2 is the only metal oxide that simultaneously possesses acidity, basicity and oxidizing and reducing properties, and it is also a p-type semiconductor that easily generates oxygen holes. As a catalyst support, it can interact with the active components and has more excellent properties.

[0021] (3) The Ni-Fe / Al2O3-ZrO2 catalyst of the present invention will not be deactivated due to carbon deposition and metal sintering during high-temperature hydrogenation, thus extending the service life of the catalyst and promoting the hydrogenation of dimethyl phthalate to prepare phthalaldehyde.

[0022] (4) The present invention uses solid-phase mechanical grinding method, and the catalyst prepared is more uniformly dispersed. The preparation process does not require the use of strong acid, strong alkali or urea ammonia water and other corrosive additives that may release toxic gases. It is simpler, has less loss, and meets the requirements of safe, efficient and environmentally friendly production.

[0023] (5) The catalyst preparation method of this invention is simple, the catalyst cost is low, the catalyst has high stability and long life, and the required equipment is simple, which greatly saves the power consumption and equipment consumables in the hydrogenation reaction of dimethyl phthalate, reduces industrial production costs and is environmentally friendly, which is of great significance for environmental improvement. It has shown excellent catalytic activity and selectivity in the hydrogenation reaction of dimethyl phthalate to prepare phthalaldehyde, and has a great competitive advantage. Attached Figure Description

[0024] Figure 1 The conversion rate of the raw materials for the reaction of the Ni-Fe / Al2O3-ZrO2 catalyst at 300-380℃ is given.

[0025] Figure 2 The selectivity of the target product, o-phthalaldehyde, in the reaction of Ni-Fe / Al2O3-ZrO2 catalyst at 300-380℃ is determined.

[0026] Figure 3 The graph shows the relationship between the number of times the Ni-Fe / Al2O3-ZrO2 catalyst is recycled and the yield of the target product, phthalaldehyde.

[0027] Figure 4 TEM images of the Ni-Fe / Al2O3-ZrO2 catalyst prepared in Example 1; (a) 50 nm; (b) 100 nm. Detailed Implementation

[0028] The present invention will be further described below with reference to embodiments, but is not limited thereto. Example 1

[0029] (1) Weigh 7.50g Al(NO3)3·9H2O and 1.23g ZrO2 into a mortar, grind thoroughly for 15min, transfer to an oven and dry at 120℃ for 12h, place in a muffle furnace and calcine at 300℃ for 4h to prepare Al2O3-ZrO2 support.

[0030] (2) Weigh 0.20g Fe(NO3)3·9H2O, 0.29g Ni(NO3)2·6H2O and the Al2O3-ZrO2 support prepared in step (1) above and place them in a beaker. Mix and stir evenly at room temperature. Place them in the polytetrafluoroethylene tank of the ball mill for mechanical ball milling. The diameter of the agate ball is 10mm, the ball-to-material ratio is 3, and the ball milling time is 60min. After the ball milling is completed, take them out of the ball mill and separate them from the agate ball. Place them in an oven at 120℃ and dry for 12h. Transfer them to a muffle furnace and calcine at 450℃ for 6h to prepare the Ni-Fe / Al2O3-ZrO2 catalyst precursor.

[0031] (3) The above Ni-Fe / Al2O3-ZrO2 catalyst precursor was placed in a tube furnace and reduced at 400℃ for 5h in a hydrogen atmosphere with a flow rate of 80mL / min to prepare Ni-Fe / Al2O3-ZrO2 catalyst.

[0032] (4) 0.3g of catalyst was loaded into a fixed-bed reactor and a solution of dimethyl phthalate with a volume flow rate of 0.1ml / min was added. Hydrogen gas was introduced to carry out the reaction at a flow rate of 80mL / min. The reaction temperature was 320℃ and the pressure was 0.1MPa. The reaction was then analyzed by gas chromatography. Example 2

[0033] (1) Weigh 7.50g Al(NO3)3·9H2O, 0.20g Fe(NO3)3·9H2O, 0.29g Ni(NO3)2·6H2O, 1.23g ZrO2 and 5.20g malonic acid into a mortar, grind thoroughly for 15min, transfer to an oven and react at 160℃ for 4h, place in a muffle furnace and calcine at 400℃ for 6h to prepare Ni-Fe / Al2O3-ZrO2 catalyst precursor.

[0034] (2) The above Ni-Fe / Al2O3-ZrO2 catalyst precursor was placed in a tube furnace and reduced at 400℃ for 5h in a hydrogen atmosphere with a flow rate of 80mL / min to prepare Ni-Fe / Al2O3-ZrO2 catalyst.

[0035] (3) 0.3g of catalyst was loaded into a fixed-bed reactor and a solution of dimethyl phthalate with a volume flow rate of 0.1ml / min was added. Hydrogen gas was introduced to carry out the reaction at a flow rate of 80mL / min. The reaction temperature was 320℃ and the pressure was 0.1MPa. The reaction was then analyzed by gas chromatography. Example 3

[0036] The difference from Example 1 is that the amount of nickel nitrate added in step (2) is 0.58g, and the rest of the operation is the same as in Example 1. Example 4

[0037] The difference from Example 1 is that the calcination temperature in step (2) is 700°C, and the rest of the operation is the same as in Example 1. Example 5

[0038] The difference from Example 1 is that the calcination temperature in step (3) is 600°C, and the rest of the operation is the same as in Example 1. Comparative Example 1

[0039] (1) Weigh 0.20g of Fe(NO3)3·9H2O and dissolve it in 30mL of deionized water. Stir well to obtain solution A. Weigh 0.29g of Ni(NO3)2·6H2O and dissolve it in 30mL of deionized water. Stir well to obtain solution B. Weigh 6.00g of neutral silica sol solution to obtain solution C.

[0040] (2) Add the above solutions A, B and C dropwise into 30 mL of deionized water, stir until sol gel, dry in an oven at 120 °C for 12 h, transfer to a muffle furnace, and calcine at 450 °C for 6 h to prepare the Ni-Fe / SiO2 catalyst precursor.

[0041] (3) The above Ni-Fe / SiO2 catalyst precursor was placed in a tube furnace and reduced at 400℃ for 5h in a hydrogen atmosphere with a flow rate of 80mL / min to prepare the Ni-Fe / SiO2 catalyst.

[0042] (4) 0.3g of catalyst was loaded into a fixed-bed reactor and a solution of dimethyl phthalate with a volume flow rate of 0.1ml / min was added. Hydrogen gas was introduced to carry out the reaction at a flow rate of 80mL / min. The reaction temperature was 320℃ and the pressure was 0.1MPa. The reaction was then analyzed by gas chromatography. Comparative Example 2

[0043] (1) Weigh 0.20g Fe(NO3)3·9H2O and dissolve it in 30mL of deionized water, stir well to obtain solution A. Weigh 0.29g Ni(NO3)2·6H2O and dissolve it in 30mL of deionized water, stir well to obtain solution B. Weigh 0.36g activated carbon carrier into 30mL of deionized water, sonicate for 30min to obtain solution C.

[0044] (2) Transfer solutions A, B and C to a polytetrafluoroethylene-lined high-pressure reactor and react at 180°C for 8 hours. After the reaction, filter, wash and dry at 120°C for 24 hours. Transfer to a muffle furnace and calcine at 450°C for 6 hours to prepare the Ni-Fe / C catalyst precursor.

[0045] (3) The above Ni-Fe / C catalyst precursor was placed in a tube furnace and reduced at 400℃ for 5h in a hydrogen atmosphere with a flow rate of 80mL / min to prepare the Ni-Fe / C catalyst.

[0046] (4) 0.3g of catalyst was loaded into a fixed-bed reactor and a solution of dimethyl phthalate with a volume flow rate of 0.1ml / min was added. Hydrogen gas was introduced to carry out the reaction at a flow rate of 80mL / min. The reaction temperature was 320℃ and the pressure was 0.1MPa. The reaction was then analyzed by gas chromatography. Comparative Example 3

[0047] The difference between this comparative example and Example 1 is that zirconium dioxide is not added in step (1). The other steps are the same as in Example 1. Comparative Example 4

[0048] The difference between this comparative example and Example 1 is that zirconium dioxide is not added in step (1) and ferric nitrate is not added in step (2). The other steps are the same as in Example 1. Comparative Example 5

[0049] The difference between this comparative example and Example 1 is that nickel nitrate is not added in step (2). The other steps are the same as in Example 1.

[0050] The data after the reaction in the examples and comparative examples were analyzed, and the results are shown in Table 1.

[0051] Table 1. Comparison of dimethyl phthalate conversion and phthalaldehyde selectivity in the examples and comparative examples

[0052] Dimethyl phthalate conversion rate, % Phthalate selectivity, % Example 1 97.3 98.9 Example 2 92.7 92.3 Example 3 94.7 88.4 Example 4 82.3 86.0 Example 5 79.5 72.8 Comparative Example 1 74.3 63.7 Comparative Example 2 70.7 58.2 Comparative Example 3 56.2 51.4 Comparative Example 4 42.8 37.4 Comparative Example 5 31.5 23.7

[0053] The composition of the Ni-Fe / Al2O3-ZrO2 catalyst prepared in Example 1 was analyzed by X-ray fluorescence spectrometry (XRF), and the oxide content was calculated. The results are shown in Table 2.

[0054] Table 2. XRF characterization of the Ni-Fe / Al2O3-ZrO2 catalyst in Example 1

[0055] Molecular formula Ni Fe <![CDATA[Al2O3]]> <![CDATA[ZrO2]]> content% 1.742 0.857 60.709 36.692

[0056] The conversion and selectivity of dimethyl phthalate under the Ni-Fe / Al2O3-ZrO2 catalyst prepared in Example 1 were further investigated. Specifically, 0.3 g of catalyst was loaded into a fixed-bed reactor, and a dimethyl phthalate solution with a volume flow rate of 0.1 mL / min was added. Hydrogen gas was introduced at a flow rate of 80 mL / min, and the reaction was carried out at temperatures of 300 °C, 320 °C, 340 °C, 360 °C, and 380 °C, with a pressure of 0.1 MPa. The reaction results were analyzed by gas chromatography. Figure 1 The conversion rate of the raw materials for the reaction of the Ni-Fe / Al2O3-ZrO2 catalyst at 300-380℃ is given. Figure 2 The selectivity of the target product, o-phthalaldehyde, in the reaction of Ni-Fe / Al2O3-ZrO2 catalyst at 300-380℃ is determined.

[0057] Figure 3 The graph shows the relationship between the number of times the Ni-Fe / Al2O3-ZrO2 catalyst is recycled and the yield of the target product, phthalaldehyde. It can be seen that the catalyst of this invention has good stability.

[0058] The bimetallic catalyst of this invention exhibits high conversion and selectivity for the hydrogenation of dimethyl phthalate to phthalaldehyde, simplifying the reaction steps and requiring simple equipment. This significantly reduces power consumption and equipment consumables in the dimethyl phthalate hydrogenation process, lowering industrial production costs and being environmentally friendly, thus having significant implications for environmental improvement. This invention prepares a Ni-Fe / Al₂O₃-ZrO₂ catalyst supported on alumina and zirconium dioxide. This method yields a bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde. Ni, as the active center, catalyzes the hydrogenation of dimethyl phthalate, lowering the reaction temperature and improving the catalyst's activity and selectivity for phthalaldehyde. The addition of Fe allows for better dispersion of Ni on the support surface, and Fe also better adsorbs dimethyl phthalate onto the support surface, improving catalyst utilization and thus enhancing the conversion and selectivity of the reactants. Al₂O₃ possesses good mechanical strength, good thermal stability, suitable pore structure, and a large surface area, making it a commonly used support for industrial Ni catalysts. ZrO₂ is the only metal oxide that simultaneously possesses acidic, basic, oxidizing, and reducing properties. Furthermore, it is a p-type semiconductor, readily generating oxygen holes. As a catalyst support, it can interact with the active component, exhibiting even more superior properties. The Ni-Fe / Al₂O₃-ZrO₂ catalyst of this invention does not suffer from catalyst deactivation due to carbon deposition and metal sintering during high-temperature hydrogenation, thus extending the catalyst's lifespan and promoting the hydrogenation of dimethyl phthalate to phthalaldehyde. The catalyst preparation method of this invention is simple, the catalyst is low in cost, highly stable, and has a long lifespan. It exhibits excellent catalytic activity and selectivity in the hydrogenation of dimethyl phthalate to phthalaldehyde, giving it a significant competitive advantage.

[0059] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde, characterized in that, The bimetallic catalyst used for the hydrogenation of dimethyl phthalate to prepare phthalaldehyde is a Ni-Fe / Al2O3-ZrO2 catalyst; in the Ni-Fe / Al2O3-ZrO2 catalyst, n(Ni):n(Fe):n(Al):n(Zr) = 0.1:0.05:2:1; The method for preparing the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde includes the following steps: (1) Aluminum nitrate and zirconium dioxide were thoroughly ground, dried, and then calcined to prepare Al2O3-ZrO2 support; (2) Weigh ferric nitrate, nickel nitrate and the Al2O3-ZrO2 support prepared in step (1), stir and mix them evenly at room temperature, put them into a ball mill for mechanical ball milling, take them out, dry them and calcine them to prepare Ni-Fe / Al2O3-ZrO2 catalyst precursor; (3) The Ni-Fe / Al2O3-ZrO2 catalyst precursor obtained in step (2) is reduced in a hydrogen atmosphere to prepare the Ni-Fe / Al2O3-ZrO2 catalyst.

2. A method for preparing a bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde as described in claim 1, characterized in that: The preparation method is as follows: (1) Aluminum nitrate and zirconium dioxide were thoroughly ground, dried, and then calcined to prepare Al2O3-ZrO2 support; (2) Weigh ferric nitrate, nickel nitrate and the Al2O3-ZrO2 support prepared in step (1), stir and mix them evenly at room temperature, put them into a ball mill for mechanical ball milling, take them out, dry them and calcine them to prepare Ni-Fe / Al2O3-ZrO2 catalyst precursor; (3) The Ni-Fe / Al2O3-ZrO2 catalyst precursor obtained in step (2) is reduced in a hydrogen atmosphere to prepare the Ni-Fe / Al2O3-ZrO2 catalyst.

3. The method for preparing the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde according to claim 2, characterized in that, The drying temperature in step (1) is 30-120℃ and the drying time is 8-48h; the calcination temperature for the calcination treatment is 200-600℃ and the calcination time is 2-12h.

4. The method for preparing the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde according to claim 2, characterized in that, Step (2) Mechanical grinding is as follows: put the agate balls into the polytetrafluoroethylene tank that comes with the ball mill for mechanical ball milling. The diameter of the agate balls is 10mm, the ball-to-material ratio is 3, and the ball milling time is 60min.

5. The method for preparing the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde according to claim 2, characterized in that, Step (2) The drying temperature is 30-120℃ and the drying time is 10-48h; the calcination temperature is 300-800℃ and the calcination time is 2-12h.

6. The method for preparing the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde according to claim 2, characterized in that, In step (3), the hydrogen flow rate is 80 mL / min, the reduction reaction temperature is 300-800℃, and the reduction reaction time is 2-12 h.

7. The application of the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde as described in claim 1, characterized in that: The Ni-Fe / Al2O3-ZrO2 catalyst was loaded into a fixed-bed reactor, and dimethyl phthalate was added. Hydrogen gas was introduced to carry out the reaction at a flow rate of 80 mL / min, a reaction temperature of 300-380℃, and a pressure of 0.1-2 MPa.

8. The application of the bimetallic catalyst for the hydrogenation of dimethyl phthalate to phthalaldehyde according to claim 7, characterized in that: The amount of Ni-Fe / Al2O3-ZrO2 catalyst used was 0.3 g; the volumetric flow rate of dimethyl phthalate was 0.1 mL / min.

Images