Catalyst for preparing N-methylmorpholine by diethylene glycol method as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for preparing N-methylmorpholine by a diethylene glycol method as well as a preparation method and application of the catalyst. According to the invention, phosphoric acid modified gamma-Al2O3-MgO is used as a carrier, and MgO is modified on the surface of Al2O3, so that not only is the crystal structure of Al2O3 ensured not to be damaged, but also the number of alkaline sites on the surface of Al2O3 is changed, and meanwhile, the addition of MgO also enhances the interaction between active component particles and the catalyst carrier; phosphorus can promote active components to be dispersed on the surface of the carrier and can promote metal to be immobilized on the carrier, so that the catalyst has better stability, and the service life of the catalyst is prolonged; the specific types of the active component and the auxiliary agent are limited, the selectivity of the N-methylmorpholine can be improved through interaction between the active component and the auxiliary agent, and the purity of the obtained product is high.

Description

Technical Field

[0001] The 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 and an application thereof. Background Art

[0002] N-methylmorpholine is an important fine chemical raw material, which has a wide range of uses in the fields of synthetic medicine and pesticides. At present, there are many methods for preparing N-methylmorpholine, which are mainly divided into morpholine method, N-methyldiethanolamine method, diethanolamine method, diethylene glycol method and dichloroethyl ether method according to the raw materials. Among them, the morpholine method is the most studied method at present because of its simple method. However, affected by the price of raw material morpholine and the need to use precious metal catalysts, the production cost of this method is high and the economic benefit is poor. Other methods have problems such as complex process, high cost, high three wastes, and low yield. Taking the diethylene glycol method as an example, diethylene glycol, methanol and liquid ammonia are used as raw materials to co-produce N-methylmorpholine and morpholine, and the yield of N-methylmorpholine is 66%, and the yield of morpholine is 23%. Since this method adopts a liquid phase method, the reaction system is prone to corrosion and copper ammonia complex is formed and lost due to the presence of a large amount of water and liquid ammonia, and the service life of the catalyst is short.

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

[0004]

[0005] This method has the advantages of easy availability of raw materials, low cost, less three wastes and high product purity. However, there are few studies on the preparation of catalysts for the one-step synthesis of diethylene glycol and methylamine. Therefore, it is urgent to provide a catalyst for the one-step synthesis of N-methylmorpholine using diethylene glycol and methylamine. Summary of the invention

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

[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 loaded 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 to 10:1; the preparation method of the phosphoric acid-modified γ-Al2O3-MgO comprises: mixing γ-Al2O3 with a phosphoric acid solution, and then 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 phosphoric acid-modified γ-Al2O3-MgO;

[0010] The active components include Ni and / or Cu; the mass of the active components accounts for 10 to 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 scheme, comprising the following steps:

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

[0015] (2) 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 obtained in step (1) with the magnesium salt mixed solution for a first impregnation, and then sequentially performing a second drying and a second calcination 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 soluble salts of Ni and / or Cu; the soluble salt of the auxiliary agent includes soluble salts 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) are independently 450-600° C., and the time of the first calcination and the second calcination are independently 4-6 hours.

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

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

[0022] Preferably, the reduction method in step (3) comprises: subjecting the solid obtained by the third calcination to a reduction reaction in a reducing gas.

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

[0024] The present invention also provides a catalyst for preparing N-methylmorpholine by the diethylene glycol method described in the above technical scheme, or use of the catalyst prepared by the preparation method described in the above technical scheme 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 loaded 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: 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 performed in sequence 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 to 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 to 5% of the mass of the catalyst. The present invention uses phosphoric acid-modified γ-Al2O3-MgO as a carrier, and MgO can be modified on the surface of Al2O3, which 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, which is conducive 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 can promote the metal to be fixed 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 active components and auxiliary agents can improve the selectivity of N-methylmorpholine through interaction, and the obtained product has a higher purity. The results of the embodiment 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 of the present invention 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 an active component and an auxiliary agent loaded on the carrier.

[0028] In the present invention, the carrier is phosphoric acid modified γ-Al2O3-MgO; the mass ratio of Al2O3 and 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 phosphoric acid modified γ-Al2O3-MgO, and more preferably 2-3%. The present invention uses phosphoric acid modified γ-Al2O3-MgO as a carrier, and MgO modifies Al2O3, which 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, which is beneficial to improve the selectivity and 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; the present invention also uses phosphoric acid modification to enhance the interaction between the active component particles, the auxiliary agent particles and the catalyst carrier, promotes the dispersion of the active component and the auxiliary agent particles, and improves 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 comprises: mixing γ-Al2O3 with a phosphoric acid solution, and then 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 phosphoric acid-modified γ-Al2O3-MgO.

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

[0031] The present invention has no special limitation on the source of the γ-Al2O3, and it can be prepared by conventional commercial 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 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 special restrictions 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 has no special limitation on the operation methods of filtering, washing and drying, and conventional filtering, washing and drying methods can be used. In the present invention, the washing agent is preferably deionized water; the drying temperature is preferably 100 to 150° C., more preferably 120 to 150° C.; the drying time is preferably 8 to 12 hours, more preferably 10 to 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 present invention uses the phosphoric acid solution with the above mass concentration, which is more conducive to fully modifying 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 specifically limit the method for mixing the γ-Al2O3 with the phosphoric acid solution, and a conventional mixing method can be used. In the present invention, the method for mixing the γ-Al2O3 with the phosphoric acid solution is preferably stirring, and the stirring time is preferably 1 to 3 hours, more preferably 2 to 3 hours. The present invention promotes the full entry of phosphoric acid into the γ-Al2O3 by stirring.

[0039] The present invention preferably filters the system after mixing γ-Al2O3 and phosphoric acid solution, and performs a first drying on the obtained solid. The present invention does not specifically limit the filtering method, and a conventional filtering method can be used to separate the solid and liquid. In the present invention, the temperature of the first drying is preferably 100 to 150°C, more preferably 110 to 140°C; the time of the first drying is preferably 8 to 12 hours, more preferably 10 to 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). The present invention uses citric acid as an auxiliary agent, mixes it with the soluble magnesium salt, and then impregnates the phosphoric acid-modified γ-Al2O3, which can play a pore expansion role, is also beneficial to the dispersion of active components, and increases 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). The present invention controls the amount of the two within the above range, so that the mass ratio of Al2O3 to MgO in the phosphoric acid-modified γ-Al2O3-MgO is 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 can be fully and evenly mixed to form a magnesium salt mixed solution.

[0046] In the present invention, the method of mixing the phosphoric acid-modified γ-Al2O3 and the magnesium salt mixed solution is preferably stirring, and the stirring time is preferably 12 to 24 hours, more preferably 24 hours. The present invention performs the first impregnation during the stirring process, so that the magnesium salt mixed solution 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 to 150° C., more preferably 110 to 140° C.; the time of the second drying is preferably 8 to 12 hours, more preferably 10 to 12 hours.

[0049] In the present invention, the temperature of the second calcination is preferably 450-600°C, more preferably 450-550°C; the time of the second calcination 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%; further, when the active component is active component 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%. The present invention controls the amount of the active component within the above range, which 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. The present invention adopts the auxiliary agent to 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%. The present invention controls the amount of the auxiliary agent within the above range, which is more conducive to improving the interaction with the active component.

[0054] The invention uses phosphoric acid-modified γ-Al2O3-MgO as a carrier, and the modification of γ-Al2O3 by MgO is beneficial to improving the purity and selectivity of N-methylmorpholine; 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 invention limits 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, and the obtained product has higher 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 scheme, comprising the following steps:

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

[0057] (2) 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 obtained in step (1) with the magnesium salt mixed solution for a first impregnation, and then sequentially performing a second drying and a second calcination 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 soluble salts of Ni and / or Cu; the soluble salt of the auxiliary agent includes soluble salts 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, which will not be described in detail 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, 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 0.5-3 mol / L, more preferably 0.5-2 mol / L; the Cu concentration is preferably 0.5-4 mol / L, more preferably 1-3 mol / L; the concentration of the soluble salt of the auxiliary agent in the mixed salt solution is preferably 0.05-0.5 mol / L, more preferably 0.05-0.2 mol / L. The present invention controls the concentration of the mixed salt solution within the above range, and can make the mass of the active component in the catalyst account for 10-35% of the mass of the catalyst through the second impregnation, and the mass of the auxiliary agent accounts for 0-5% of the mass of the catalyst.

[0065] In the present invention, the method for mixing the phosphoric acid-modified γ-Al2O3-MgO with the mixed salt solution is preferably ultrasound, the power of the ultrasound is preferably 100-200 W, more preferably 120-150 W; the time of the ultrasound is preferably 10-30 min, more preferably 20-30 min. The present invention can increase the specific surface area and pore volume of the catalyst carrier through ultrasound, thereby improving the dispersion of the active components on the carrier.

[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 make the mixed salt solution fully distributed 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 to 120° C., more preferably 100 to 120° C.; the time of the third drying is preferably 6 to 12 hours, more preferably 10 to 12 hours.

[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 4-6h, more preferably 5-6h. 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 subjecting the solid to a reduction reaction.

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

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

[0073] In the present invention, the temperature of the reduction reaction is preferably 400-500°C, more preferably 450-500°C; the time of the reduction reaction is preferably 6-12h, more preferably 8-12h; the pressure of the reduction reaction is preferably 0.1-0.5MPa, more preferably 0.2-0.4MPa. The present invention controls the parameters of the reduction reaction within the above range, which is more conducive to the full reduction of the oxide to form active components and auxiliary metal particles.

[0074] The operation method provided by the 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 catalyst carriers; phosphorus can promote the dispersion of active components on the surface of the carrier, 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 invention limits 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 scheme, or use of the catalyst prepared by the preparation method described in the above technical scheme 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 application method of the catalyst can be used.

[0077] In the present invention, the method for using the catalyst in the one-step synthesis of N-methylmorpholine preferably includes: loading the catalyst into a fixed bed reactor, using methylamine and diethylene glycol as raw materials, respectively, gasifying them in a vaporizer and 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 product by gas-liquid separation, and removing ammonia from the liquid product in a deamination tower to obtain the final product N-methylmorpholine. The schematic 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 technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part 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 creative work 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, wherein 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 obtained colloidal precipitate, wash it with deionized water for 3 times, dry the obtained solid in an oven at 110° C. for 10 h, and calcine the dried solid at 450° C. for 6 h to obtain γ-Al2O3; mix γ-Al2O3 with 25% phosphoric acid solution by 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 for the first calcination to obtain phosphoric acid-modified γ-Al2O3;

[0085] (2) 50 g of Mg(NO3)2·6H2O was dissolved in 200 mL of deionized water, and after magnetic stirring for 30 min, an appropriate amount of citric acid was added, the molar ratio of magnesium salt to citric acid was 1:3, and the mixture was evenly mixed to obtain a magnesium salt mixed solution; phosphorus-modified γ-Al2O3 was added to the magnesium salt mixed solution and stirred for 24 h for a first impregnation, and then filtered, and the obtained solid was dried in an oven at 110°C for 8 h for a second drying, and calcined at 550°C for 4 h for a 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. After cooling and grinding, it was 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 rise to 400° C., and the reduction reaction time was controlled to be 8 h and the pressure to be 0.1 MPa. 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 and an active component and an auxiliary agent loaded on the carrier;

[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 filtering, the obtained solid was dried at 80° C. for 6 h for a third drying. After cooling and grinding, it was 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 rise to 450° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.1 MPa. 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 and an active component and an auxiliary agent loaded on the carrier;

[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 mass of the catalyst;

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

[0101] (1) to (2) are the same as in 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 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. After cooling and grinding, it was 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 rise to 450° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.1 MPa. A reduction reaction was performed to obtain catalyst 3, which was recorded as Cu-Pb-γAl2O3-MgO.

[0103] Example 4

[0104] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier and an active component and an auxiliary agent loaded on the carrier;

[0105] 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;

[0106] The active components are Cu and Ni, and the mass of the active components 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 additive is Co, and the mass of the additive accounts for 4.83% of the mass of the catalyst;

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

[0109] (1) to (2) are the same as in 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 filtering, the obtained solid was dried at 80° C. for 6 h for a third drying. After cooling and grinding, it was 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 rise to 500° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.2 MPa. 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 and an active component and an auxiliary agent loaded on the carrier;

[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 mass of the catalyst;

[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. After cooling and grinding, it was 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 rise to 500° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.2 MPa. 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 and an active component and an auxiliary agent loaded on the carrier;

[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 filtering, the obtained solid was dried at 80° C. for 6 h for a third drying. After cooling and grinding, it was 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 rise to 400° C., and the reduction reaction time was controlled to be 10 h and the pressure to be 0.1 MPa. 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 and an active component and an auxiliary agent loaded on the carrier;

[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 components are Cu and Ni, and the mass of the active components 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 additive is Zr, and the mass of the additive accounts for 2.28% of the mass of the catalyst;

[0132] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0133] (1) to (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 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. After cooling and grinding, it was 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 rise to 500° C., and the reduction reaction time was controlled to be 6 h and the pressure to be 0.1 MPa. A reduction reaction was performed to obtain catalyst 7, which was recorded as Cu-Ni-Zr-γAl2O3-MgO.

[0135] Example 8

[0136] A catalyst for preparing N-methylmorpholine by a diethylene glycol process, comprising a carrier and an active component and an auxiliary agent loaded on the carrier;

[0137] 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;

[0138] The active components are Cu and Ni, and the mass of the active components 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 additive is Sn, and the mass of the additive accounts for 2.56% of the mass of the catalyst;

[0140] The preparation method of the catalyst for preparing N-methylmorpholine by the above-mentioned diethylene glycol method is:

[0141] (1) to (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 filtering, the obtained solid was dried at 80° C. for 6 h for a third drying. After cooling and grinding, it was 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 rise to 400° C., and the reduction reaction time was controlled to be 8 h and the pressure to be 0.1 MPa. A reduction reaction was performed 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 used respectively according to the following methods:

[0145] a. Take 100 g of the catalyst prepared in Example 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 a 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 to 0.5 h -1 , gas-solid reaction was carried out under the action of catalyst and H2 at 195℃ and 1.5Mpa;

[0149] e. After the reaction product is separated into gas and liquid, the obtained liquid product is deaminated in a deammoniation 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 shown in Table 1.

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

[0152]

[0153] It can be seen from the above experimental results 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 high purity. This is because the present invention uses phosphoric acid to modify γ-Al2O3-MgO as a carrier, and 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 active components on the carrier surface, and can promote the metal to be fixed 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 active components and auxiliary agents can improve the selectivity of N-methylmorpholine through interaction, and the obtained product has 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 principle of the present invention. These improvements and modifications should also be regarded as 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 to 10:1; the preparation method of the phosphoric acid-modified γ-Al2O3-MgO comprises: After mixing γ-Al2O3 with a phosphoric acid solution, first drying and first calcining are performed in sequence 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 is mixed with the magnesium salt mixed solution for a first impregnation, and then second drying and second calcining are performed in sequence 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 to 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.

2. The catalyst for preparing N-methylmorpholine by the diethylene glycol method according to claim 1, characterized in that: 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) after mixing γ-Al2O3 with a phosphoric acid solution, performing a first drying and a first calcination in sequence to obtain phosphoric acid-modified γ-Al2O3; (2) 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 obtained in step (1) with the magnesium salt mixed solution for 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 the 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, Co, Mo, 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 temperatures of the first calcination in step (1) and the second calcination in step (2) are independently 450-600° C., and the times 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 the 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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