A metal skeleton catalyst and its preparation method and application

Abstract

The invention belongs to the technical field of catalysts, and specifically discloses a metal skeleton catalyst and a preparation method and application thereof. The catalyst comprises a skeleton nickel-aluminum main catalyst, at least one co-catalyst selected from Cr, Sn, Fe, Cu, Co and Zn is introduced into the skeleton nickel, and at least one element selected from rare earth metals Pt, Ru, Pd and Sm is further included. The metal skeleton catalyst is used for continuous hydrogenation to prepare metaphenylenediamine, and the conversion rate of isophthalonitrile is 100%, and the selectivity of metaphenylenediamine can be ≥95%.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a metal skeleton catalyst and a preparation method and application thereof. Background Art

[0002] Meta-phenylenediamine is widely used in rubber additives, photosensitive materials, pesticides, coatings, fiber finishing agents, rust removers, chelating agents, lubricants, paper processing and other products. Meta-phenylenediamine is usually prepared by liquid phase hydrogenation of isophthalonitrile. The most used catalyst in the hydrogenation process is Raney-Ni. However, the existing Raney-Ni catalyst has the problems of rapid activity reduction, large consumption due to loss, low selectivity of meta-phenylenediamine, and high production energy consumption. Improvement research has been carried out on this catalyst at home and abroad. CN 1774390A uses Raney-Ni to catalyze the decomposition of sodium borohydride to produce hydrogen. It adopts two methods to solve the loss problem of powdered Raney-Ni. One is to attach Raney-Ni to a magnet with a catalyst fixing unit and soak it in water; the other is to fix Raney-Ni on a nickel net with polyurethane foam and then store it in distilled water. Both of the above methods make the reaction device more complicated. When the reaction liquid flows through the fixed bed Raney nickel catalyst at a high flow rate, the catalyst is easily broken and falls off. Moreover, when the concentration of borohydride is reduced to 2 wt% or below, the hydrogen generation rate decreases rapidly, so its application is limited.

[0003] Yu Xiaobing et al. (Guangzhou Chemistry, 1999, 21: 23-27) and Irina et al. (Appl. Catal. A Gen., 2009, 356, 216-224) reported the method of hydrogenating α-pinene using Pd / C as catalyst. The substrate conversion rate of this method can reach 99%, but the selectivity is only 80.1%, which is too low. Yu Xiaobing et al. (Guangzhou Chemistry, 1999, 21: 23-27) modified the Pd / C catalyst with CuCl2, and the selectivity of cis-pinene increased to 93.1%, but the substrate conversion rate decreased to 63.3% in the same reaction time.

[0004] CN1283359C discloses a skeleton metal catalyst for fixed bed hydrogenation and its preparation method. The catalyst is prepared by directly kneading, molding, roasting and activating with caustic solution, using alloy powder of aluminum and one or more metal elements of nickel, cobalt, copper and iron, using a colloid prepared from inorganic substances such as pseudo-boehmite as a binder, and natural or synthetic organic substances such as sesbania powder and carboxymethyl cellulose as a pore template. The alloy powder in the embodiment is nickel-aluminum alloy powder, and the catalyst after roasting contains only nickel as a component, and has low mechanical strength. Summary of the invention

[0005] The purpose of the present invention is to provide a metal skeleton catalyst and a preparation method and application thereof. The catalyst prepared by the method has the advantages of high conversion rate, good selectivity, high catalyst activity and strength.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A metal skeleton catalyst comprises a skeleton nickel-aluminum main catalyst, at least one promoter selected from Cr, Sn, Fe, Cu, Co and Zn is introduced into the skeleton nickel, and at least one element selected from rare earth metals Pt, Ru, Pd and Sm is also included. The main catalyst, the promoter and the rare earth element are composited to form a solid heterogeneous catalyst of fine grains of nickel-aluminum alloy with a porous structure.

[0008] Furthermore, the main catalyst nickel is used in an amount of 90-92%, the co-catalyst is used in an amount of 1-5%, the rare earth metal is used in an amount of 0-0.5%, and the rest is aluminum.

[0009] Furthermore, the promoter is Cr or Co.

[0010] A method for preparing a metal skeleton catalyst comprises the following steps: grinding a nickel-aluminum alloy into a powder of 50-500 μm, adding the powder into a mixed solution of NaOH, a metal salt and ammonia water to dissolve for 2-12 hours, washing the metal powder with deionized water and anhydrous ethanol for standby use; mixing the powder into a rare earth metal acid or salt containing (including at least one of Pt, Ru, Pd and Sm) one or more of (chloroplatinic acid, potassium tetrachloroplatinate, potassium hexachloroplatinate, sodium perruthenate, potassium perruthenate, chloropalladate and samarium perchlorate), putting the powder into a 10% nickel chloride solution, heating to 50-100° C. under stirring conditions, keeping the temperature constant for 1-36 hours, drying the obtained solid, calcining at 180-250° C. for 1-6 hours, introducing hydrogen at a pressure of 2-10 MPa, reducing at a temperature of 50-120° C. for 6 hours to obtain a modified Raney nickel catalyst.

[0011] The invention discloses an application of a metal skeleton catalyst, characterized in that the metal skeleton catalyst is used in the continuous hydrogenation preparation of m-phenylenediamine.

[0012] The catalyst of the present invention can continuously produce meta-xylylenediamine by hydrogenation catalysis of isophthalonitrile under mild conditions, with a conversion rate of isophthalonitrile of 100% and a selectivity of meta-xylylenediamine of ≥95%. Since the nickel-aluminum alloy is added to a sodium hydroxide solution and then the aluminum reacts in the process of washing away the residual liquid, many holes will be left, and the reaction itself produces hydrogen, and the metal nickel has a strong affinity for hydrogen, so it has good catalytic activity; on the other hand, in the presence of a co-catalyst, it is more conducive to the reaction of primary amines, so that the finally prepared catalyst has a higher catalytic activity; the presence of a co-catalyst is conducive to the formation of a stable polyhedral alloy material, thereby increasing the skeleton strength, and the alloy composite material has high strength and is not easy to collapse; the co-catalyst also reduces the catalyst poisoning performance, so that the catalyst has a longer service life. The catalyst of the present invention has a moderate catalytic rate and is suitable for continuous industrial production of meta-xylylenediamine. DETAILED DESCRIPTION

[0013] Example 1

[0014] 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and added into 500ml of 3mol / L NaOH solution and 1.13g of chromium chloride and ammonia water mixed solution to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for later use; the above powder is added into 100ml of 10% nickel chloride deionized water solution, and heated to 50-100℃, preferably 75-95℃, under stirring conditions; the temperature is kept constant for 1-36h, preferably 8-16h; the obtained solid is dried and roasted at 180-250℃ for 1-6h, and put into a fixed bed reactor for nitrogen replacement, and then hydrogen with a pressure of 2-10MPa, preferably 3-7Mpa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

[0015] Example 2

[0016] 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and the powder is added into a mixed solution of 500ml 3mol / L NaOH solution and 0.54g chromium chloride and ammonia water to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for use; the powder is mixed with 0.0178g potassium perruthenate, added into 100ml 10% nickel chloride aqueous solution, and heated to 50-100℃, preferably 75-95℃, under stirring; the temperature is kept constant for 1-36h, preferably 8-16h; the obtained solid is dried and roasted at 180-250℃ for 1-6h, put into a fixed bed reactor, replaced with nitrogen, and then hydrogen at a pressure of 2-10MPa, preferably 3-7Mpa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

[0017] Example 3

[0018] 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and the powder is added into a mixed solution of 500ml 3mol / L NaOH solution and 0.54g chromium chloride and ammonia water to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for later use; the powder is mixed with 0.0178g potassium perruthenate and 0.02g potassium hexachloropalladate, and the powder is added into 100ml 10% nickel chloride aqueous solution, and the mixture is heated to 50-100℃, preferably 75-95℃, under stirring; preferably 8-16h; the mixture is kept at a constant temperature for 1-36h, and the obtained solid is dried and roasted at 180-250℃ for 1-6h, and then put into a fixed bed reactor for nitrogen replacement, and then hydrogen with a pressure of 2-10MPa, preferably 3-7Mpa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

[0019] Example 4

[0020] 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and added into a mixed solution of 500ml3mol / L NaOH solution and 0.82g cobalt chloride and ammonia water to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for later use; the above powder is added into 100ml10% nickel chloride deionized water solution, and heated to 50-100℃, preferably 75-95℃, under stirring; the temperature is kept constant for 1-36h, and the obtained solid is dried and roasted at 180-250℃ for 1-6h, and put into a fixed bed reactor for nitrogen replacement, and then hydrogen with a pressure of 2-10MPa, preferably 3-7Mpa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

[0021] Example 5

[0022] 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and the powder is added into a mixed solution of 500ml 3mol / L NaOH solution and 0.39g cobalt chloride and ammonia water to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for later use; the powder is mixed with 0.0178g potassium perruthenate and 0.02g potassium hexachloropalladate, and the powder is added into 100ml 10% nickel chloride aqueous solution, and the mixture is heated to 50-100℃, preferably 75-95℃, under stirring; the temperature is kept constant for 1-36h, and the obtained solid is dried and roasted at 180-250℃ for 1-6h, and then put into a fixed bed reactor for nitrogen replacement, and then hydrogen with a pressure of 2-10MPa, preferably 3-7Mpa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

[0023] Example 6

[0024] 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and the powder is added into a mixed solution of 500ml 3mol / L NaOH solution, 0.39g cobalt chloride, 0.27g chromium chloride and ammonia water to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for later use; the powder is mixed with 0.0178g potassium perruthenate and 0.02g potassium hexachloropalladate, and added into 100ml 10% nickel chloride aqueous solution, and heated to 50-100℃, preferably 75-95℃, under stirring; the temperature is kept constant for 1-36h, and the obtained solid is dried and roasted at 180-250℃ for 1-6h, and then put into a fixed bed reactor for nitrogen replacement, and then hydrogen with a pressure of 2-10MPa, preferably 3-7Mpa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

[0025] Example 7

[0026] 20.0g of nickel-aluminum alloy was ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy was 7.7:1, and added into a mixed solution of 500ml 3mol / L NaOH solution, 0.59g cobalt chloride, 0.27g chromium chloride, and ammonia water to dissolve for 2-12h, and the metal powder was washed with deionized water and anhydrous ethanol for later use; the above powder was mixed with 0.0178g potassium perruthenate, 0.011g potassium hexachloropalladate, 0.003g Samarium perchlorate is added to 100 ml of 10% nickel chloride aqueous solution, and heated to 50-100° C., preferably 75-95° C., under stirring; the temperature is kept constant for 1-36 hours, the obtained solid is dried and calcined at 180-250° C. for 1-6 hours, and then put into a fixed bed reactor for nitrogen replacement, and then hydrogen at a pressure of 2-10 MPa, preferably 3-7 MPa, is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120° C. for 6 hours.

[0027] Example 8

[0028] 20.0g of nickel-aluminum alloy was ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy was 7.7:1, and added into a mixed solution of 500ml 3mol / L NaOH solution, 0.29g cobalt chloride, 0.41g chromium chloride, and ammonia water to dissolve for 2-12h, and the metal powder was washed with deionized water and anhydrous ethanol for later use; the above powder was mixed with 0.0143g potassium perruthenate, 0.0264g potassium hexachloropalladate, 0.003g samarium perchlorate, and 0.0143g potassium perruthenate, 0.0264g potassium hexachloropalladate, and 0.003g samarium perchlorate. Add 100 ml of 10% nickel chloride aqueous solution, heat to 50-100° C., preferably 75-95° C., under stirring; keep constant temperature for 1-36 hours, preferably 8-16 hours; dry the obtained solid and calcine at 180-250° C. for 1-6 hours, put it into a fixed bed reactor, replace it with nitrogen, and then introduce hydrogen at a pressure of 2-10 MPa, preferably 3-7 MPa; reduce it at a temperature of 50-120° C. for 6 hours to obtain a modified Raney nickel catalyst.

[0029] The invention discloses an application of a metal skeleton catalyst, wherein the metal skeleton catalyst is used for continuous hydrogenation to prepare meta-phenylenediamine.

[0030] According to the method of the present invention, a plurality of different types of catalysts were prepared and applied to continuous production. The specific effect experiments are shown in the following table: The experiments were all carried out on a continuous production device, and the data obtained by continuous calibration and continuous operation for 72 hours were:

[0031]

Claims

1. A method for preparing a metal skeleton catalyst, characterized in that: The method comprises: 20.0g of nickel-aluminum alloy is ground into powder of 50-500μm, wherein the nickel-aluminum ratio of the nickel-aluminum alloy is 7.7:1, and the powder is added into a mixed solution of 500ml 3mol / L NaOH solution, 0.29g cobalt chloride, 0.41g chromium chloride and ammonia water to dissolve for 2-12h, and the metal powder is washed with deionized water and anhydrous ethanol for use; the powder is mixed with 0.0143g potassium perruthenate, 0.0264g potassium hexachloropalladate, and 0.003g samarium perchlorate, and added into 100ml 10% nickel chloride aqueous solution, and heated to 75-95℃ under stirring conditions; the temperature is kept constant for 8-16h; the obtained solid is dried and roasted at 180-250℃ for 1-6h, and then put into a fixed bed reactor for nitrogen replacement, and then hydrogen with a pressure of 3-7Mpa is introduced; and the modified Raney nickel catalyst is obtained after reduction at a temperature of 50-120℃ for 6h.

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