A catalyst for preparing n-methylmorpholine by diethylene glycol method, a preparation method and application thereof

Abstract

The application provides a catalyst for preparing N-methylmorpholine by a diethylene glycol method and a preparation method and application thereof. The catalyst is prepared by using phosphoric acid modified gamma-Al2O3-MgO as a carrier, and MgO is modified on the surface of Al2O3, so that the crystal structure of Al2O3 is ensured not to be damaged, the number of basic sites on the surface of Al2O3 is changed, and the interaction between the active component particles and the catalyst carrier is enhanced; the phosphorus can promote the dispersion of the active component on the surface of the carrier, and can promote the immobilization of the metal on the carrier, so that the catalyst has good stability and the service life of the catalyst is prolonged; the specific types of the active component and the additive are limited, the selectivity of N-methylmorpholine can be improved through the interaction between the active component and the additive, and the obtained product has high purity.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a catalyst for preparing N-methylmorpholine through a diethylene glycol process, a preparation method thereof and an application thereof. Background Art

[0002] N-methylmorpholine is an important fine chemical raw material with a wide range of applications in fields such as synthetic pharmaceuticals and pesticides. Currently, there are numerous methods for preparing N-methylmorpholine, primarily categorized by raw materials: the morpholine method, the N-methyldiethanolamine method, the diethanolamine method, the diethylene glycol method, and the dichloroethyl ether method. The morpholine method, due to its simplicity, is the most widely studied method. However, due to the price of the raw material morpholine and the need for a precious metal catalyst, this method has high production costs and poor economic benefits. Other methods suffer from complex processes, high costs, high levels of waste, waste products, and low yields. For example, the diethylene glycol method, using diethylene glycol, methanol, and liquid ammonia as raw materials to co-produce N-methylmorpholine and morpholine, yields 66% for N-methylmorpholine and 23% for morpholine. Because this method utilizes a liquid-phase process, the presence of large amounts of water and liquid ammonia in the reaction system easily corrodes the copper in the catalyst, forming a copper-ammonia complex that is lost, resulting in a short catalyst life.

[0003] The one-step synthesis method using diethylene glycol and methylamine as raw materials is a new process improved from the diethylene glycol method. This method is simple to operate, and its reaction equation is as follows:

[0004] .

[0005] This method has the advantages of readily available raw materials, low cost, low waste, and high product purity. However, there is currently little research on the preparation of catalysts for the one-step synthesis of diethylene glycol and methylamine. Therefore, there is an urgent need to provide a catalyst for the one-step synthesis of N-methylmorpholine using diethylene glycol and methylamine. Summary of the Invention

[0006] The present invention aims to provide a catalyst for preparing N-methylmorpholine by the diethylene glycol process, a preparation method thereof, and applications thereof. The catalyst provided by the present invention has the characteristics of high selectivity, high dispersity, long life, and good stability when used for the one-step synthesis of N-methylmorpholine by the diethylene glycol process.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a catalyst for preparing N-methylmorpholine by a diethylene glycol method, comprising a carrier and an active component and an auxiliary agent supported on the carrier;

[0009] The carrier is phosphoric acid-modified γ-Al2O3-MgO; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 2-10:1; the preparation method of the phosphoric acid-modified γ-Al2O3-MgO comprises: mixing γ-Al2O3 with a phosphoric acid solution, and sequentially performing a first drying and a first calcination to obtain phosphoric acid-modified γ-Al2O3; mixing a soluble magnesium salt solution with a citric acid solution to obtain a magnesium salt mixed solution, mixing the phosphoric acid-modified γ-Al2O3 with the magnesium salt mixed solution for a first impregnation, and then sequentially performing a second drying and a second calcination to obtain the phosphoric acid-modified γ-Al2O3-MgO;

[0010] The active components include Ni and / or Cu; the mass of the active components accounts for 10-35% of the mass of the catalyst;

[0011] The auxiliary agent includes one or more of La, Pb, Co, Mo, Mn, Zr and Sn; the mass of the auxiliary agent accounts for 0-5% of the mass of the catalyst.

[0012] Preferably, the mass of phosphorus in the carrier accounts for 1-3% of the mass of phosphoric acid-modified γ-Al2O3-MgO.

[0013] The present invention also provides a method for preparing a catalyst for preparing N-methylmorpholine by the diethylene glycol method described in the above technical solution, comprising the following steps:

[0014] (1) After mixing γ-Al2O3 with a phosphoric acid solution, a first drying and a first calcination are performed in sequence to obtain phosphoric acid-modified γ-Al2O3;

[0015] (2) a soluble magnesium salt solution is mixed with a citric acid solution to obtain a magnesium salt mixture, the phosphoric acid-modified γ-Al2O3 obtained in step (1) is mixed with the magnesium salt mixture to perform a first impregnation, and then a second drying and a second calcination are performed in sequence to obtain phosphoric acid-modified γ-Al2O3-MgO;

[0016] (3) dissolving the soluble salt of the active component and the soluble salt of the auxiliary agent in deionized water to obtain a mixed salt solution, mixing the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) with the mixed salt solution and performing a second impregnation, and then sequentially performing a third drying, a third calcination and a reduction to obtain a catalyst;

[0017] The soluble salt of the active component in step (3) includes a soluble salt of Ni and / or Cu; the soluble salt of the auxiliary agent includes a soluble salt of one or more of La, Pb, Co, Mo, Mn, Zr and Sn.

[0018] Preferably, the mass concentration of the phosphoric acid solution in step (1) is 8-25%.

[0019] Preferably, the temperature of the first calcination in step (1) and the second calcination in step (2) is independently 450-600℃, and the time of the first calcination and the second calcination is independently 4-6h.

[0020] Preferably, the molar ratio of the soluble magnesium salt and the citric acid in step (2) is 1:(1-4).

[0021] Preferably, the temperature of the third calcination in step (3) is 400-550℃, and the time of the third calcination is 2-4h.

[0022] Preferably, the method of reduction in step (3) comprises: reducing the solid obtained from the third calcination in a reducing gas.

[0023] Preferably, the temperature of the reduction reaction is 400-500℃, the time of the reduction reaction is 6-12h, and the pressure of the reduction reaction is 0.1-0.5MPa.

[0024] The application also provides the use of the catalyst for preparing N-methylmorpholine by the diethylene glycol method or the catalyst prepared by the preparation method in the one-step synthesis of N-methylmorpholine.

[0025] The invention provides a catalyst for preparing N-methylmorpholine by a diethylene glycol method, comprising a carrier and an active component and an auxiliary agent supported on the carrier; the carrier is phosphoric acid-modified γ-Al2O3-MgO; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 2-10:1; the preparation method of the phosphoric acid-modified γ-Al2O3-MgO comprises the following steps: mixing γ-Al2O3 with a phosphoric acid solution, and then sequentially performing a first drying and a first calcination to obtain the phosphoric acid-modified γ-Al2O3; A soluble magnesium salt solution is mixed with a citric acid solution to obtain a magnesium salt mixed solution, the phosphoric acid-modified γ-Al2O3 is mixed with the magnesium salt mixed solution for a first impregnation, and then a second drying and a second calcination are sequentially performed to obtain phosphoric acid-modified γ-Al2O3-MgO; the active component includes Ni and / or Cu; the mass of the active component accounts for 10-35% of the mass of the catalyst; the auxiliary agent includes one or more of La, Pb, Co, Mo, Mn, Zr and Sn; the mass of the auxiliary agent accounts for 0-5% of the mass of the catalyst. The present invention uses phosphoric acid-modified γ-Al2O3-MgO as a carrier. MgO can be modified on the Al2O3 surface, which not only ensures that the crystal structure of Al2O3 is not destroyed, but also changes the number of basic sites on the Al2O3 surface, which is beneficial to improving the purity of N-methylmorpholine. At the same time, the addition of MgO also enhances the interaction between the active component particles and the catalyst carrier. Phosphorus can promote the dispersion of the active component on the carrier surface and promote the immobilization of the metal on the carrier, thereby making the catalyst have better stability and extending the service life of the catalyst. The present invention defines the specific types of active components and auxiliary agents. The interaction between the active components and auxiliary agents can improve the selectivity of N-methylmorpholine, and the resulting product has a high purity. The results of the examples show that when the catalyst provided by the present invention is used to synthesize N-methylmorpholine, the selectivity of N-methylmorpholine is 97.1~98.5%, and the purity of N-methylmorpholine reaches 98.2~99.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a schematic flow chart of a method for using the catalyst prepared in Examples 1 to 8 in the synthesis of N-methylmorpholine. DETAILED DESCRIPTION

[0027] The invention provides a catalyst for preparing N-methylmorpholine by a diethylene glycol method, comprising a carrier and active components and auxiliary agents supported on the carrier.

[0028] In the present invention, the carrier is phosphoric acid-modified γ-Al2O3-MgO; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 2-10:1, preferably 2-6:1, and more preferably 4:1; the mass of phosphorus in the carrier preferably accounts for 1-3% of the mass of the phosphoric acid-modified γ-Al2O3-MgO, and more preferably 2-3%. The present invention uses phosphoric acid-modified γ-Al2O3-MgO as a carrier. MgO modifies Al2O3, ensuring that the crystal structure of Al2O3 is not destroyed and changing the number of basic sites on the Al2O3 surface, which is beneficial for improving the selectivity and purity of N-methylmorpholine. The addition of MgO also enhances the interaction between the active component particles and the catalyst support. The present invention also utilizes phosphoric acid modification to enhance the interaction between the active component particles, the auxiliary agent particles, and the catalyst support, promoting the dispersion of the active component and auxiliary agent particles, and improving the catalytic performance of the catalyst. The present invention controls the mass ratio of Al2O3 to MgO within the above range, which is more conducive to improving the catalytic performance of the catalyst.

[0029] In the present invention, the preparation method of the phosphoric acid-modified γ-Al2O3-MgO includes: mixing γ-Al2O3 with a phosphoric acid solution, and then performing a first drying and a first calcination in sequence to obtain phosphoric acid-modified γ-Al2O3; mixing a soluble magnesium salt solution with a citric acid solution to obtain a magnesium salt mixed solution, mixing the phosphoric acid-modified γ-Al2O3 with the magnesium salt mixed solution for a first impregnation, and then performing a second drying and a second calcination in sequence to obtain phosphoric acid-modified γ-Al2O3-MgO.

[0030] The present invention mixes gamma-Al2O3 with a phosphoric acid solution, and then sequentially performs a first drying and a first calcination to obtain phosphoric acid-modified gamma-Al2O3.

[0031] The present invention does not particularly limit the source of the γ-Al2O3, and can be prepared using conventional commercially available products or preparation methods. In an embodiment of the present invention, the preparation method of the γ-Al2O3 preferably comprises: adding ammonia water to a soluble aluminum salt solution, performing a precipitation reaction, and then filtering, washing, drying, and calcining in sequence to obtain the γ-Al2O3.

[0032] In the present invention, the soluble aluminum salt solution is preferably an aluminum nitrate solution. The present invention has no particular limitation on the concentration of the aluminum nitrate solution, which can be adjusted as needed.

[0033] The present invention has no particular limitation on the concentration and dosage of the ammonia water, as long as the pH value of the soluble aluminum salt solution can be adjusted to 9 to 10. The present invention can fully precipitate the soluble aluminum salt by adjusting the pH value of the soluble aluminum salt solution.

[0034] The present invention does not specifically limit the filtering, washing, and drying methods; conventional filtering, washing, and drying methods may be employed. In the present invention, the washing agent is preferably deionized water; the drying temperature is preferably 100-150°C, more preferably 120-150°C; and the drying time is preferably 8-12 hours, more preferably 10-12 hours.

[0035] In the present invention, the calcination temperature is preferably 450-600° C., more preferably 500-550° C.; the calcination time is preferably 4-6 hours, more preferably 5-6 hours.

[0036] In the present invention, the mass concentration of the phosphoric acid solution is preferably 8-25%, more preferably 25%. The use of the phosphoric acid solution with the above mass concentration is more conducive to fully modifying the γ-Al2O3.

[0037] The present invention has no particular limitation on the ratio of the mass of the γ-Al2O3 to the volume of the phosphoric acid solution, as long as the liquid level of the phosphoric acid solution is higher than that of the γ-Al2O3.

[0038] The present invention does not particularly limit the method for mixing the γ-Al2O3 and phosphoric acid solution; conventional mixing methods may be employed. In the present invention, the γ-Al2O3 and phosphoric acid solution are preferably mixed by stirring, and the stirring time is preferably 1 to 3 hours, more preferably 2 to 3 hours. Stirring promotes the full incorporation of phosphoric acid into the γ-Al2O3.

[0039] The present invention preferably filters the mixture of γ-Al2O3 and phosphoric acid solution, and then performs a first drying on the resulting solid. The present invention does not specifically limit the filtering method; conventional filtering methods can be used to separate the solid and liquid. In the present invention, the temperature for the first drying is preferably 100-150°C, more preferably 110-140°C; and the first drying time is preferably 8-12 hours, more preferably 10-12 hours.

[0040] In the present invention, the temperature of the first calcination is preferably 450-600°C, more preferably 450-550°C; the time of the first calcination is preferably 4-6 hours, more preferably 5-6 hours. The present invention can form a precursor with a γ-Al2O3 crystal form through the first calcination.

[0041] After obtaining phosphoric acid-modified γ-Al2O3, the present invention mixes a soluble magnesium salt solution with a citric acid solution to obtain a magnesium salt mixed solution, mixes the phosphoric acid-modified γ-Al2O3 with the magnesium salt mixed solution for a first impregnation, and then sequentially performs a second drying and a second calcination to obtain phosphoric acid-modified γ-Al2O3-MgO.

[0042] In the present invention, the soluble magnesium salt is preferably magnesium nitrate.

[0043] In the present invention, the molar ratio of the soluble magnesium salt to citric acid is preferably 1:(1-4), more preferably 1:(2-3). Citric acid is used as an adjuvant in the present invention. After mixing it with the soluble magnesium salt, the phosphoric acid-modified γ-Al2O3 is impregnated, which can expand the pores, facilitate the dispersion of the active components, and increase the catalytic activity of the catalyst.

[0044] In the present invention, the molar ratio of the soluble magnesium salt to γ-Al2O3 is preferably 1:(0.78-3.92), more preferably 1:(1-2). By controlling the amounts of the soluble magnesium salt and γ-Al2O3 within the above range, the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO can be 2-10:1.

[0045] The present invention has no particular limitation on the method for mixing the soluble magnesium salt solution and the citric acid solution, as long as the two are fully mixed to form a magnesium salt mixed solution.

[0046] In the present invention, the phosphoric acid-modified γ-Al2O3 and the magnesium salt mixture are preferably mixed by stirring, and the stirring time is preferably 12 to 24 hours, more preferably 24 hours. The first impregnation is performed during the stirring process, so that the magnesium salt mixture can be fully impregnated into the phosphoric acid-modified γ-Al2O3.

[0047] In the present invention, it is preferred to perform filtration after the first impregnation and perform a second drying on the obtained solid.

[0048] In the present invention, the temperature of the second drying is preferably 100-150° C., more preferably 110-140° C.; the time of the second drying is preferably 8-12 h, more preferably 10-12 h.

[0049] In the present invention, the second calcination temperature is preferably 450-600°C, more preferably 450-550°C; the second calcination time is preferably 4-6 hours, more preferably 5-6 hours. The present invention can convert magnesium ions into magnesium oxide through the second calcination.

[0050] In the present invention, the active component includes Ni and / or Cu. The present invention uses Ni and / or Cu as the active component, and the obtained catalyst has higher selectivity for N-methylmorpholine.

[0051] In the present invention, the mass of the active component accounts for 10-35% of the mass of the catalyst, preferably 12-30%. Furthermore, when the active components are Cu and Ni, the mass of Ni accounts for preferably 5-10% of the mass of the catalyst, more preferably 5-6%; the mass of Cu accounts for preferably 5-20% of the mass of the catalyst, more preferably 18-20%. Controlling the amount of the active component within the above range is more conducive to improving the selectivity and activity of the catalyst for N-methylmorpholine.

[0052] In the present invention, the auxiliary agent includes one or more of La, Pb, Co, Mo, Mn, Zr and Sn, preferably La, Pb, Co or Mo. By using the auxiliary agent, the present invention can interact with the active component to improve the catalytic activity of the catalyst and the selectivity for N-methylmorpholine.

[0053] In the present invention, the mass of the auxiliary agent accounts for 0-5% of the mass of the catalyst, preferably 0.5-5%. In the present invention, the amount of the auxiliary agent is controlled within the above range, which is more conducive to improving the interaction with the active component.

[0054] The present invention uses phosphoric acid-modified γ-Al2O3-MgO as a carrier. The modification of γ-Al2O3 by MgO is beneficial to improving the purity and selectivity of N-methylmorpholine. Simultaneously, the addition of MgO also enhances the interaction between active component particles and the catalyst carrier. Phosphorus can promote the dispersion of active components on the carrier surface and promote the immobilization of metals on the carrier, thereby making the catalyst have better stability and extending the service life of the catalyst. The present invention limits the specific types of active components and auxiliary agents. The active components and auxiliary agents can improve the selectivity of N-methylmorpholine through interaction, and the obtained product has high purity.

[0055] The present invention also provides a method for preparing a catalyst for preparing N-methylmorpholine by the diethylene glycol method described in the above technical solution, comprising the following steps:

[0056] (1) After mixing γ-Al2O3 with a phosphoric acid solution, a first drying and a first calcination are performed in sequence to obtain phosphoric acid-modified γ-Al2O3;

[0057] (2) a soluble magnesium salt solution is mixed with a citric acid solution to obtain a magnesium salt mixture, the phosphoric acid-modified γ-Al2O3 obtained in step (1) is mixed with the magnesium salt mixture to perform a first impregnation, and then a second drying and a second calcination are performed in sequence to obtain phosphoric acid-modified γ-Al2O3-MgO;

[0058] (3) dissolving the soluble salt of the active component and the soluble salt of the auxiliary agent in deionized water to obtain a mixed salt solution, mixing the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) with the mixed salt solution and performing a second impregnation, and then sequentially performing a third drying, a third calcination and a reduction to obtain a catalyst;

[0059] The soluble salt of the active component in step (3) includes a soluble salt of Ni and / or Cu; the soluble salt of the auxiliary agent includes a soluble salt of one or more of La, Pb, Co, Mo, Mn, Zr and Sn.

[0060] In the present invention, the preparation method of the phosphoric acid-modified γ-Al2O3-MgO is the same as the above technical solution and will not be described again here.

[0061] After obtaining phosphoric acid-modified γ-Al2O3-MgO, the present invention dissolves the soluble salt of the active component and the soluble salt of the auxiliary agent in deionized water to obtain a mixed salt solution, mixes the phosphoric acid-modified γ-Al2O3-MgO with the mixed salt solution, and then performs a second impregnation, and then sequentially performs a third drying, a third calcination and reduction to obtain a catalyst.

[0062] In the present invention, the soluble salt of the active component includes a soluble salt of Ni and / or Cu. In the present invention, the soluble salt of Ni and / or Cu is preferably a nitrate of Ni and / or Cu.

[0063] In the present invention, the soluble salt of the auxiliary agent includes soluble salts of one or more of La, Pb, Co, Mo, Mn, Zr and Sn, preferably nitrates of one or more of La, Pb, Co, Mo, Mn, Zr and Sn.

[0064] In the present invention, the Ni concentration of the soluble salt of the active component in the mixed salt solution is preferably 0.5 to 3 mol / L, more preferably 0.5 to 2 mol / L; the Cu concentration is preferably 0.5 to 4 mol / L, more preferably 1 to 3 mol / L; and the concentration of the soluble salt of the additive in the mixed salt solution is preferably 0.05 to 0.5 mol / L, more preferably 0.05 to 0.2 mol / L. By controlling the concentration of the mixed salt solution within the above range, the present invention can achieve, through the second impregnation, a catalyst with the mass of the active component accounting for 10 to 35% of the catalyst mass and the mass of the additive accounting for 0 to 5% of the catalyst mass.

[0065] In the present invention, the phosphoric acid-modified γ-Al2O3-MgO is preferably mixed with the mixed salt solution by ultrasound. The ultrasound power is preferably 100-200 W, more preferably 120-150 W, and the ultrasound duration is preferably 10-30 minutes, more preferably 20-30 minutes. The present invention utilizes ultrasound to increase the specific surface area and pore volume of the catalyst support, thereby improving the dispersion of the active component on the support.

[0066] In the present invention, the second impregnation time is preferably 2 to 36 hours, more preferably 2 to 24 hours. The present invention can fully distribute the mixed salt solution in the carrier through impregnation.

[0067] In the present invention, it is preferred to perform filtration after the second impregnation and perform a third drying on the obtained solid.

[0068] In the present invention, the temperature of the third drying is preferably 80-120° C., more preferably 100-120° C.; the time of the third drying is preferably 6-12 h, more preferably 10-12 h.

[0069] In the present invention, the temperature of the third calcination is preferably 400-550°C, more preferably 400°C; the time of the third calcination is preferably 4-6 hours, more preferably 5-6 hours. The present invention can form corresponding oxides from the active component and the auxiliary agent through the third calcination.

[0070] In the present invention, the reduction method preferably comprises: subjecting the solid obtained by the third calcination to a reduction reaction in a reducing gas, more preferably placing the solid obtained by the third calcination in a reducing gas flow, heating the temperature to a reduction reaction temperature, and then subjecting the solid to a reduction reaction.

[0071] In the present invention, the flow rate of the reducing gas flow is preferably 20-60 mL / min, more preferably 40-50 mL / min.

[0072] In the present invention, the reducing gas is preferably hydrogen.

[0073] In the present invention, the reduction reaction temperature is preferably 400-500°C, more preferably 450-500°C; the reduction reaction time is preferably 6-12 hours, more preferably 8-12 hours; and the reduction reaction pressure is preferably 0.1-0.5 MPa, more preferably 0.2-0.4 MPa. Controlling the reduction reaction parameters within the above ranges facilitates the full reduction of the oxides to form active components and additive metal particles.

[0074] The operation method provided by the present invention is simple, and the modification of Al2O3 by MgO not only ensures that the crystal structure of Al2O3 is not destroyed, but also changes the number of basic sites on the surface of Al2O3. At the same time, the addition of MgO also enhances the interaction between active component particles and the catalyst carrier. Phosphorus can promote the dispersion of active components on the carrier surface and can promote the immobilization of metals on the carrier, thereby making the catalyst have better stability and extending the service life of the catalyst. The present invention defines the specific types of active components and auxiliary agents, and the selectivity of N-methylmorpholine can be improved through the interaction between the active components and the auxiliary agents.

[0075] The present invention also provides a catalyst for preparing N-methylmorpholine by the diethylene glycol method described in the above technical solution, or use of the catalyst prepared by the preparation method described in the above technical solution in the one-step synthesis of N-methylmorpholine.

[0076] The present invention has no special limitation on the application method of the catalyst in the one-step synthesis of N-methylmorpholine, and a conventional catalyst application method can be adopted.

[0077] In the present invention, the method for using the catalyst in the one-step synthesis of N-methylmorpholine preferably comprises: loading the catalyst into a fixed-bed reactor, using methylamine and diethylene glycol as raw materials, gasifying them in a vaporizer and then entering a mixer, mixing them with H2 from a compressor, and then entering a fixed-bed reactor, performing a gas-solid reaction under the action of the catalyst and H2, separating the reaction products by gas and liquid, and deammoniating the liquid product in a deamination tower to obtain the final product, N-methylmorpholine. The flow diagram of the method for using the catalyst in the one-step synthesis of N-methylmorpholine is preferably as follows: Figure 1 shown.

[0078] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0079] Example 1

[0080] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier and an active component supported on the carrier;

[0081] The carrier is phosphoric acid-modified γ-Al2O3-MgO; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid-modified γ-Al2O3-MgO;

[0082] The active components are Ni and Cu, and the mass of the active components accounts for 18.23% of the mass of the catalyst, of which the mass of Cu accounts for 12.76% of the mass of the catalyst and the mass of Ni accounts for 5.47% of the mass of the catalyst;

[0083] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0084] (1) Weigh 200 g of Al(NO3)3·9H2O and dissolve it in 300 mL of deionized water. After magnetic stirring for 30 min, add ammonia water to adjust the pH to 9. Filter the resulting colloidal precipitate and wash it three times with deionized water. Dry the resulting solid in an oven at 110 °C for 10 h. After drying, calcine the solid at 450 °C for 6 h to obtain γ-Al2O3. Mix γ-Al2O3 with 25% phosphoric acid solution under magnetic stirring for 1 h and filter it. Then, dry it in an oven at 110 °C for 4 h for the first drying and calcine it at 550 °C for 4 h to obtain phosphoric acid-modified γ-Al2O3.

[0085] (2) Take 50g of Mg(NO3)2·6H2O and dissolve it in 200mL of deionized water. After magnetic stirring for 30min, add an appropriate amount of citric acid, the ratio of magnesium salt to citric acid is 1:3, and mix evenly to obtain a magnesium salt mixture; add phosphorus-modified γ-Al2O3 to the magnesium salt mixture and stir for 24h for the first impregnation, then filter, dry the obtained solid in an oven at 110℃ for 8h for the second drying, and calcine at 550℃ for 4h for the second calcination to obtain phosphoric acid-modified γ-Al2O3-MgO;

[0086] (3) 148.0 g of copper nitrate and 82.5 g of nickel nitrate were dissolved in 200 mL of deionized water and magnetically stirred for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) and the mixed salt solution were ultrasonically treated at 120 W for 30 min, and then a second impregnation was performed for 2 h. After filtering, the obtained solid was dried at 80° C. for 6 h for a third drying, cooled and ground, and then calcined at 400° C. for 4 h for a third calcination. Thereafter, the solid obtained by the third calcination was placed in a 40 mL / min hydrogen flow, programmed to 400° C., and the reduction reaction time was controlled to be 8 h and the pressure was controlled to be 0.1 MPa, and a reduction reaction was performed to obtain catalyst 1, which was recorded as Cu-Ni-γAl2O3-MgO.

[0087] Example 2

[0088] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier, an active component supported on the carrier, and an auxiliary agent;

[0089] The carrier is phosphoric acid-modified γ-Al2O3-MgO prepared in Example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid-modified γ-Al2O3-MgO;

[0090] The active component is Cu, and the mass of the active component accounts for 16.53% of the mass of the catalyst;

[0091] The additive is La, and the mass of the additive accounts for 3.71% of the mass of the catalyst;

[0092] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0093] (1) to (2) are the same as in Example 1;

[0094] (3) 198.8 g of copper nitrate and 28.4 g of lanthanum nitrate were dissolved in 200 mL of deionized water and magnetically stirred for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) and the mixed salt solution were ultrasonically treated at 150 W for 20 min, and then a second impregnation was performed for 2 h. After filtration, the obtained solid was dried at 80 ° C for 6 h for a third drying, cooled and ground, and calcined at 400 ° C for 4 h for a third calcination. Thereafter, the solid obtained by the third calcination was placed in a 60 mL / min hydrogen flow, programmed to 450 ° C, and the reduction reaction time was controlled to be 6 h and the pressure was controlled to be 0.1 MPa, and a reduction reaction was performed to obtain catalyst 2, which was recorded as Cu-La-γAl2O3-MgO.

[0095] Example 3

[0096] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier, an active component supported on the carrier, and an auxiliary agent;

[0097] The carrier is phosphoric acid-modified γ-Al2O3-MgO prepared in Example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid-modified γ-Al2O3-MgO;

[0098] The active component is Cu, and the mass of the active component accounts for 14.65% of the mass of the catalyst;

[0099] The additive is Pb, and the mass of the additive accounts for 1.32% of the catalyst mass;

[0100] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0101] (1) (2) are the same as example 1;

[0102] (3) 167.3 g of copper nitrate and 7.1 g of lead nitrate were dissolved in 200 mL of deionized water, and magnetic stirring was performed for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid modified γ-Al2O3-MgO obtained in step (2) was ultrasonically treated with the mixed salt solution at 150 W for 20 min, and then a second impregnation was performed for 2 h. After filtration, the obtained solid was dried at 80°C for 6 h for a third drying, and after cooling and grinding, a third calcination was performed at 400°C for 4 h. Then, the solid obtained by the third calcination was placed in a hydrogen gas stream of 50 mL / min, and a programmed temperature rise to 450°C was performed, and the reduction reaction was performed by controlling the reduction reaction time to 6 h and the pressure to 0.1 MPa, to obtain the catalyst 3, which is denoted as Cu-Pb-γAl2O3-MgO.

[0103] Example 4

[0104] A catalyst for preparing N-methylmorpholine by a diethylene glycol method, which is composed of a carrier and an active component and an auxiliary agent supported on the carrier;

[0105] The carrier is the phosphoric acid modified γ-Al2O3-MgO prepared in example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid modified γ-Al2O3-MgO;

[0106] The active component is Cu and Ni, and the mass of the active component accounts for 25.93% of the mass of the catalyst, wherein the mass of Cu accounts for 17.58% of the mass of the catalyst, and the mass of Ni accounts for 8.35% of the mass of the catalyst;

[0107] The auxiliary agent is Co, and the mass of the auxiliary agent accounts for 4.83% of the mass of the catalyst;

[0108] The preparation method of the above-mentioned catalyst for preparing N-methylmorpholine by a diethylene glycol method is as follows:

[0109] (1) (2) are the same as example 1;

[0110] (3) 121.8 g of copper nitrate, 75.0 g of nickel nitrate and 30.3 g of cobalt nitrate were dissolved in 200 mL of deionized water and magnetically stirred for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) and the mixed salt solution were ultrasonically treated at 150 W for 20 min, and then a second impregnation was performed for 2 h. After filtration, the obtained solid was dried at 80° C. for 6 h for a third drying, cooled and ground, and then calcined at 400° C. for 4 h for a third calcination. Thereafter, the solid obtained by the third calcination was placed in a 50 mL / min hydrogen flow, programmed to 500° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.2 MPa, and a reduction reaction was performed to obtain catalyst 4, which was recorded as Cu-Ni-Co-γAl2O3-MgO.

[0111] Example 5

[0112] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier, an active component supported on the carrier, and an auxiliary agent;

[0113] The carrier is phosphoric acid-modified γ-Al2O3-MgO prepared in Example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid-modified γ-Al2O3-MgO;

[0114] The active component is Cu, and the mass of the active component accounts for 14.93% of the mass of the catalyst;

[0115] The additive is Mo, and the mass of the additive accounts for 4.26% of the catalyst mass;

[0116] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0117] (1) to (2) are the same as in Example 1;

[0118] (3) 174.6 g of copper nitrate and 43.8 g of molybdenum nitrate were dissolved in 200 mL of deionized water and magnetically stirred for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) and the mixed salt solution were ultrasonically treated at 150 W for 20 min, and then a second impregnation was performed for 2 h. After filtering, the obtained solid was dried at 80° C. for 6 h for a third drying, cooled and ground, and then calcined at 400° C. for 4 h for a third calcination. Thereafter, the solid obtained by the third calcination was placed in a 60 mL / min hydrogen flow, programmed to 500° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.2 MPa, and a reduction reaction was performed to obtain catalyst 5, which was recorded as Cu-Mo-γAl2O3-MgO.

[0119] Example 6

[0120] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier, an active component supported on the carrier, and an auxiliary agent;

[0121] The carrier is phosphoric acid-modified γ-Al2O3-MgO prepared in Example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid-modified γ-Al2O3-MgO;

[0122] The active component is Cu, and the mass of the active component accounts for 10.59% of the mass of the catalyst;

[0123] The additive is Mn, and the mass of the additive accounts for 1.63% of the mass of the catalyst;

[0124] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0125] (1) to (2) are the same as in Example 1;

[0126] (3) 114.5 g of copper nitrate and 21.5 g of manganese nitrate were dissolved in 200 mL of deionized water and magnetically stirred for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) and the mixed salt solution were ultrasonically treated at 150 W for 20 min, and then a second impregnation was performed for 2 h. After filtration, the obtained solid was dried at 80° C. for 6 h for a third drying, cooled and ground, and then calcined at 400° C. for 4 h for a third calcination. Thereafter, the solid obtained by the third calcination was placed in a 60 mL / min hydrogen flow, programmed to 400° C., and the reduction reaction time was controlled to be 10 h and the pressure to be 0.1 MPa, and a reduction reaction was performed to obtain catalyst 6, which was recorded as Cu-Mn-γAl2O3-MgO.

[0127] Example 7

[0128] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier, an active component supported on the carrier, and an auxiliary agent;

[0129] The carrier is phosphoric acid-modified γ-Al2O3-MgO prepared in Example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid-modified γ-Al2O3-MgO;

[0130] The active component is Cu and Ni, the mass of the active component accounts for 19.38% of the mass of the catalyst, wherein the mass of Cu accounts for 13.64% of the mass of the catalyst, and the mass of Ni accounts for 5.74% of the mass of the catalyst;

[0131] The assistant is Zr, and the mass of the assistant accounts for 2.28% of the mass of the catalyst;

[0132] The preparation method of the catalyst for preparing N-methyl morpholine by the diethylene glycol method is as follows:

[0133] (1) and (2) are the same as in Example 1;

[0134] (3) 164.6 g of copper nitrate, 90.5 g of nickel nitrate, and 35.2 g of zirconium nitrate are dissolved in 200 mL of deionized water, magnetically stirred for 30 min to obtain a mixed salt solution, 100 g of the phosphoric acid modified γ-Al2O3-MgO obtained in step (2) is ultrasonically treated with the mixed salt solution at 150 W for 20 min, then secondly impregnated for 2 h, and after filtration, the obtained solid is dried at 80°C for 6 h for third drying, and after cooling and grinding, it is calcined at 400°C for 4 h for third calcination, then the solid obtained by the third calcination is placed in a hydrogen gas flow of 50 mL / min, and a programmed temperature rising to 500°C is carried out, and the reduction reaction time is controlled to be 6 h, the pressure is 0.1 MPa, and the reduction reaction is carried out, thereby obtaining the catalyst 7, which is denoted as Cu-Ni-Zr-γAl2O3-MgO.

[0135] Example 8

[0136] A catalyst for preparing N-methyl morpholine by the diethylene glycol method, which is composed of a carrier and an active component and an assistant supported on the carrier;

[0137] The carrier is the phosphoric acid modified γ-Al2O3-MgO prepared in Example 1; the mass ratio of Al2O3 to MgO in the phosphoric acid modified γ-Al2O3-MgO is 4:1, and the mass of phosphorus in the carrier accounts for 1.5% of the mass of the phosphoric acid modified γ-Al2O3-MgO;

[0138] The active component is Cu and Ni, the mass of the active component accounts for 21.65% of the mass of the catalyst, wherein the mass of Cu accounts for 15.13% of the mass of the catalyst, and the mass of Ni accounts for 6.52% of the mass of the catalyst;

[0139] The assistant is Sn, and the mass of the assistant accounts for 2.56% of the mass of the catalyst;

[0140] The preparation method of the catalyst for preparing N-methyl morpholine by the diethylene glycol method is as follows:

[0141] (1) and (2) are the same as in Example 1;

[0142] (3) 188.7 g of copper nitrate, 106.5 g of nickel nitrate and 26.3 g of tin nitrate were dissolved in 200 mL of deionized water and magnetically stirred for 30 min to obtain a mixed salt solution. 100 g of the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) and the mixed salt solution were ultrasonically treated at 150 W for 20 min, and then a second impregnation was performed for 2 h. After filtration, the obtained solid was dried at 80°C for 6 h for a third drying, cooled and ground, and calcined at 400°C for 4 h for a third calcination. Thereafter, the solid obtained by the third calcination was placed in a 30 mL / min hydrogen flow, programmed to 400°C, and the reduction reaction time was controlled to be 8 h and the pressure was controlled to be 0.1 MPa to perform a reduction reaction to obtain catalyst 8, which was recorded as Cu-Ni-Sn-γAl2O3-MgO.

[0143] Application Example 1

[0144] The catalysts prepared in Examples 1 to 8 were applied according to the following methods:

[0145] a. Take 100g of the catalyst prepared in Example 1 and load it into a fixed bed reactor;

[0146] b. Methylamine and diethylene glycol are used as raw materials (feed molar ratio 1:1-3), and are pressurized into the vaporizer through the feed pump;

[0147] c. The vaporized methylamine and diethylene glycol enter the mixer and mix with the H2 from the compressor;

[0148] d. The mixed gas enters the fixed bed reactor with a volume space velocity of 0.1~0.5h -1 , in the presence of catalyst and H2, gas-solid reaction is carried out at 195℃ and 1.5Mpa;

[0149] e. After the reaction product is separated into gas and liquid, the resulting liquid product is deaminated in a deamination tower to obtain the final product N-methylmorpholine.

[0150] Catalysts 1 to 8 were used to prepare N-methylmorpholine according to the above method, and the feed ratio of methylamine and diethylene glycol and the reaction conditions were adjusted. The catalyst conditions and the purity and selectivity of the obtained product N-methylmorpholine are detailed in Table 1.

[0151] Table 1 Test results of selectivity and product purity of the catalysts prepared in Examples 1 to 8 for N-methylmorpholine

[0152]

[0153] From the above experimental results, it can be seen that when the catalyst prepared by the present invention is used to synthesize N-methylmorpholine, the selectivity of N-methylmorpholine is 97.1~98.5%, and the purity of N-methylmorpholine reaches 98.2~99.5%, which has excellent selectivity and the obtained product has a high purity. This is because the present invention uses phosphoric acid to modify γ-Al2O3-MgO as a carrier. MgO can be modified on the Al2O3 surface, which not only ensures that the crystal structure of Al2O3 is not destroyed, but also changes the number of basic sites on the Al2O3 surface. At the same time, the addition of MgO also enhances the interaction between the active component particles and the catalyst carrier; phosphorus can promote the dispersion of the active component on the carrier surface and promote the immobilization of the metal on the carrier, thereby making the catalyst have better stability and extending the service life of the catalyst; the present invention limits the specific types of active components and auxiliary agents, and the interaction between the active components and auxiliary agents can improve the selectivity of N-methylmorpholine, and the obtained product has a high purity.

[0154] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier and an active component and an auxiliary agent supported on the carrier; The carrier is phosphoric acid-modified γ-Al2O3-MgO; the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 2-10:1; and the preparation method of the phosphoric acid-modified γ-Al2O3-MgO comprises: γ-Al2O3 is mixed with a phosphoric acid solution and filtered, and the obtained solid is sequentially dried and calcined to obtain phosphoric acid-modified γ-Al2O3; a soluble magnesium salt solution is mixed with a citric acid solution to obtain a magnesium salt mixed solution, the phosphoric acid-modified γ-Al2O3 and the magnesium salt mixed solution are mixed and first impregnated, and then second drying and second calcination are sequentially performed to obtain phosphoric acid-modified γ-Al2O3-MgO; The active components include Ni and / or Cu; the mass of the active components accounts for 10-35% of the mass of the catalyst; The auxiliary agent includes one or more of La, Pb, Mn, Zr and Sn; the mass of the auxiliary agent accounts for 0.5-5% of the mass of the catalyst.

2. The catalyst for preparing N-methylmorpholine by the diethylene glycol method according to claim 1, wherein The mass of phosphorus in the carrier accounts for 1-3% of the mass of phosphoric acid-modified γ-Al2O3-MgO.

3. The method for preparing a catalyst for preparing N-methylmorpholine by the diethylene glycol method according to claim 1 or 2, comprising the following steps: (1) mixing γ-Al2O3 with a phosphoric acid solution and filtering the mixture, and sequentially performing a first drying and a first calcination on the obtained solid to obtain phosphoric acid-modified γ-Al2O3; (2) mixing a soluble magnesium salt solution with a citric acid solution to obtain a magnesium salt mixture, mixing the phosphoric acid-modified γ-Al2O3 obtained in step (1) with the magnesium salt mixture to perform a first impregnation, and then sequentially performing a second drying and a second calcination to obtain phosphoric acid-modified γ-Al2O3-MgO; (3) dissolving the soluble salt of the active component and the soluble salt of the auxiliary agent in deionized water to obtain a mixed salt solution, mixing the phosphoric acid-modified γ-Al2O3-MgO obtained in step (2) with the mixed salt solution and performing a second impregnation, and then sequentially performing a third drying, a third calcination and a reduction to obtain a catalyst; The soluble salt of the active component in step (3) includes soluble salts of Ni and / or Cu; the soluble salt of the auxiliary agent includes soluble salts of one or more of La, Pb, Mn, Zr and Sn.

4. The preparation method according to claim 3, characterized in that The mass concentration of the phosphoric acid solution in step (1) is 8-25%.

5. The preparation method according to claim 3, characterized in that The temperature of the first calcination in step (1) and the second calcination in step (2) are independently 450-600° C., and the time of the first calcination and the second calcination are independently 4-6 hours.

6. The preparation method according to claim 3, characterized in that The molar ratio of the soluble magnesium salt to the citric acid in step (2) is 1:(1-4).

7. The preparation method according to claim 3, characterized in that The temperature of the third calcination in step (3) is 400-550° C., and the time of the third calcination is 2-4 hours.

8. The preparation method according to claim 3, characterized in that The reduction method in step (3) comprises: subjecting the solid obtained by the third calcination to a reduction reaction in a reducing gas.

9. The preparation method according to claim 8, characterized in that The temperature of the reduction reaction is 400-500° C., the time of the reduction reaction is 6-12 hours, and the pressure of the reduction reaction is 0.1-0.5 MPa.

10. Use of the catalyst for preparing N-methylmorpholine by the diethylene glycol method according to any one of claims 1 to 2 or the catalyst prepared by the preparation method according to any one of claims 3 to 9 in the one-step synthesis of N-methylmorpholine.

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