Metal-loaded molecular sieve catalyst, its preparation method and application

Abstract

The application discloses a transition metal supported molecular sieve catalyst and a preparation method and application thereof. The preparation method of the transition metal supported molecular sieve catalyst comprises the following steps: etching treatment of a molecular sieve by using an organic base to form a molecular sieve with multistage pores and defects; immersing the molecular sieve subjected to the etching treatment in a transition metal salt solution, and then drying and calcining to load the transition metal on the multistage pores and defect positions of the molecular sieve; and ion exchange of the molecular sieve subjected to the calcining to obtain the transition metal supported molecular sieve catalyst. The preparation process of the supported molecular sieve catalyst is simple, the cost is low, the prepared supported molecular sieve catalyst is suitable for acid catalytic reactions, especially suitable for a 3-hydroxypropionaldehyde reaction prepared by hydrating propenal, and the supported molecular sieve catalyst has good catalytic activity and regeneration capacity.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation and application technology, specifically relating to a transition metal supported molecular sieve catalyst, its preparation method, and its application. Background Technology

[0002] PTT polyester fiber is formed by the polymerization of terephthalic acid and 1,3-propanediol. PTT fiber has superior performance and broad prospects. Currently, the insufficient production capacity of the constituent monomer 1,3-propanediol restricts the industry's development. As of the end of 2022, the Chinese 1,3-propanediol market size was less than 50,000 tons / year, and the output was less than 20,000 tons / year. As an important monomer for the synthesis of PTT, the large-scale production of 1,3-propanediol has always been a research focus. The production of 1,3-propanediol by the hydrogenation of acrolein hydration is the main method for the large-scale production of 1,3-propanediol, and the acrolein hydration catalyst is the key focus of process development.

[0003] Acrolein hydration is carried out via acid catalysis. Resin catalysts are favored in industrial applications due to their excellent catalytic activity. However, the activity of resin catalysts slowly decreases with use due to the covering of hydration reaction byproducts on the active sites. Furthermore, as high-molecular polymers, they cannot be regenerated by calcination, resulting in high usage and disposal costs. Molecular sieves, with their unique pore structure, play an important role in regulating reaction products and possess acidic sites, making them suitable as catalysts in acrolein hydration. However, molecular sieves generally exhibit low selectivity, necessitating modification to improve their catalytic activity. Summary of the Invention

[0004] The main objective of this invention is to provide a transition metal supported molecular sieve catalyst, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a method for preparing a transition metal supported molecular sieve catalyst, comprising:

[0007] The molecular sieve is etched with an organic base to form a molecular sieve with multi-level channels and defects;

[0008] The etched molecular sieve is immersed in a transition metal salt solution, then dried and calcined, so that the transition metal is loaded onto the multi-level channels and defect sites contained in the molecular sieve.

[0009] Ion exchange was performed on the calcined molecular sieve to obtain a transition metal supported molecular sieve catalyst.

[0010] Furthermore, the preparation method of the transition metal supported molecular sieve catalyst includes: immersing the molecular sieve in an organic base solution with a concentration of 0.01~0.3mol / L for etching, wherein the ratio of molecular sieve to organic base solution is 100g:100~400mL, the etching temperature is 50~90℃, the etching time is 4~8h, filtering and washing, and drying at 100~120℃ for 6~24h to obtain a molecular sieve with multi-level channels and defects.

[0011] Furthermore, the preparation method of the transition metal supported molecular sieve catalyst includes: immersing the etched molecular sieve in a transition metal salt solution with a concentration of 0.025~5 mol / L, the immersion temperature being 30~50℃, the immersion time being 6~12h, filtering, drying at 100~120℃ for 6~24h, and calcining at 500~600℃ for 3~6h to obtain the transition metal supported molecular sieve catalyst.

[0012] Further, the preparation method of the transition metal supported molecular sieve catalyst includes: placing the above-mentioned transition metal supported molecular sieve catalyst in an ammonium salt with a concentration of 1~2 mol / L, wherein the mass ratio of molecular sieve to ammonium salt is 1:10~30, exchanging at 60~90℃ for 1~3 h, filtering and washing, repeating this exchange step 2~4 times, drying at 100~120℃ for 6~24 h, and calcining at 500~600℃ for 3~6 h; wherein the ammonium salt includes any one or more of ammonium sulfate, ammonium chloride, and ammonium nitrate.

[0013] Furthermore, the preparation method of the transition metal supported molecular sieve catalyst further includes: mixing the transition metal supported molecular sieve catalyst with boehmite at a mass ratio of 1:0.5~1.5, and binding the resulting mixed powder with a 5wt% nitric acid aqueous solution, wherein the mass ratio of the mixed powder to the 5wt% nitric acid aqueous solution is 1:0.6~0.8. The catalyst is then obtained by forming a strip-shaped catalyst using a molding device, dried at 100~120℃ for 12~24h, and then the strip-shaped catalyst is crushed into 1~4nm particles and calcined at 500~600℃ for 3~6h.

[0014] The present invention also provides a transition metal supported molecular sieve catalyst prepared by the aforementioned method, wherein the transition metal supported molecular sieve catalyst has a transition metal loading of 0.05~10 wt%.

[0015] The present invention also provides the application of the aforementioned transition metal supported molecular sieve catalyst in acid-catalyzed reactions, preferably in the preparation of 3-hydroxypropional by the hydration of acrolein.

[0016] The present invention also provides a method for preparing 3-hydroxypropanal, comprising: reacting an acrolein solution with the aforementioned transition metal supported molecular sieve catalyst to obtain 3-hydroxypropanal;

[0017] The acrolein solution is prepared by adding 200-2000 ppm hydroquinone to a 5-20 wt% acrolein aqueous solution and mixing them evenly.

[0018] The process conditions for the contact reaction include: a reaction temperature of 45~70℃;

[0019] The mass ratio of acrolein to water in the acrolein aqueous solution is 5:95 to 20:80.

[0020] The mass hourly space velocity (MSV) of the acrolein is 0.1–3 h⁻¹. -1 .

[0021] In the hydration reaction, the transition metal supported molecular sieve catalyst of this invention suffers from reduced catalyst activity due to the polymer formed by byproducts covering the catalyst surface. This catalyst is an inorganic solid acid catalyst and can be regenerated at high temperature. The regeneration steps include: heating the catalyst to 100~120℃, drying for 6~24h, heating to 500~600℃ at a heating rate of 2~10℃ / min under air or oxygen atmosphere, and calcining for 2~12h to remove the polymer covering the catalyst surface and restore the catalyst's catalytic activity.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The preparation of the supported molecular sieve catalyst of the present invention mainly includes alkali treatment, metal loading and ion exchange steps. The preparation process of the present invention is simple and low cost. The obtained supported molecular sieve catalyst is suitable for acid catalytic reactions, especially for the reaction of acrolein hydration to prepare 3-hydroxypropionaldehyde, and has good catalytic activity and regeneration ability.

[0024] (2) By loading the selected transition metal onto the molecular sieve, the present invention increases the amount of acid in the catalyst and adjusts the acid strength, effectively improving the catalytic activity of the molecular sieve and inhibiting the occurrence of side reactions. Compared with traditional resin catalysts, it increases the catalytic life and reduces the cost of using the catalyst. Detailed Implementation

[0025] To overcome the shortcomings of existing technologies, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. This invention mainly provides a novel method for preparing a molecular sieve catalyst and its applications. This catalyst is a transition metal-supported molecular sieve catalyst. When used in the acrolein hydration reaction, this catalyst can effectively improve reaction activity, suppress side reactions, and reduce catalyst usage costs. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0026] One aspect of this invention provides a method for preparing a transition metal supported molecular sieve catalyst, comprising:

[0027] The molecular sieve is etched with an organic base to widen the pores and form a molecular sieve with multi-level pores and defects.

[0028] The etched molecular sieve is immersed in a transition metal salt solution, then dried and calcined, so that the transition metal is loaded onto the multi-level channels and defect sites contained in the molecular sieve.

[0029] Ion exchange was performed on the calcined molecular sieve to obtain a transition metal supported molecular sieve catalyst.

[0030] In some preferred embodiments, the preparation method of the transition metal supported molecular sieve catalyst includes: immersing the molecular sieve in an organic base solution with a concentration of 0.01~0.3mol / L for etching, wherein the ratio of molecular sieve to organic base solution is 100g:100~400mL, the etching temperature is 50~90℃, the etching time is 4~8h, and the sieve is dried at 100~120℃ for 6~24h to obtain a molecular sieve with multi-level channels and defects.

[0031] In this embodiment of the invention, organic base etching is used to increase the formation defects of molecular sieves, widen the channels, and form a multi-level channel structure.

[0032] In some more preferred embodiments, the molecular sieve may include any one or a combination of two or more of MCM-41, MCM-48, SBA-15, ZSM-5, Y-type molecular sieves, etc., but is not limited thereto.

[0033] In some more preferred embodiments, the organic base solution may include a tetramethylammonium hydroxide solution and / or a tetraethylammonium hydroxide solution.

[0034] In some preferred embodiments, the preparation method of the transition metal supported molecular sieve catalyst includes: immersing the etched molecular sieve in a transition metal salt solution with a concentration of 0.025~5 mol / L, the immersion temperature being 30~50℃, the immersion time being 6~12h, filtering and washing, drying at 100~120℃ for 6~24h, and calcining at 500~600℃ for 3~6h.

[0035] In some more preferred embodiments, the transition metal salt in the transition metal salt solution may include any one or a combination of two or more of transition metal halide, transition metal sulfate, transition metal nitrate, transition metal acetate, and transition metal ammonium salt, but is not limited thereto; wherein the transition metal element contained may include any one or a combination of two or more of aluminum, titanium, zinc, gallium, and zirconium, but is not limited thereto.

[0036] In this embodiment of the invention, metal impregnation is introduced into the inner wall of the molecular sieve pores to increase the acidic sites of the molecular sieve, adjust the acid strength of the catalyst, and improve the catalytic activity of the catalyst in the acrolein hydration reaction.

[0037] In some preferred embodiments, the preparation method of the transition metal supported molecular sieve catalyst includes: placing the above-mentioned transition metal supported molecular sieve catalyst in an ammonium salt with a concentration of 1-2 mol / L, wherein the mass ratio of molecular sieve to ammonium salt is 1:10-30, exchanging at 60-90°C for 1-3 h, filtering and washing, repeating this exchange step 2-4 times, drying at 100-120°C for 6-24 h, and calcining at 500-600°C for 3-6 h; wherein the ammonium salt includes any one or more of ammonium sulfate, ammonium chloride, and ammonium nitrate.

[0038] In this embodiment of the invention, the purpose of ion exchange is to exchange the molecular sieve for an H-type molecular sieve, remove some impurity ions contained in the molecular sieve, and facilitate the reaction.

[0039] In some preferred embodiments, the preparation method of the transition metal supported molecular sieve catalyst further includes: mixing the transition metal supported molecular sieve catalyst with boehmite at a mass ratio of 1:0.5~1.5, and binding the resulting mixed powder with a 5wt% nitric acid aqueous solution, wherein the mass ratio of the mixed powder to the 5wt% nitric acid aqueous solution is 1:0.6~0.8. The catalyst is then obtained as a strip by a molding device, dried at 100~120℃ for 12~24h, and then the strip catalyst is crushed into 1~4nm particles and calcined at 500~600℃ for 3~6h.

[0040] In summary, the purpose of the initial alkali treatment in this embodiment of the invention is to etch the catalyst, forming multi-level channels and some defect sites without destroying the original molecular sieve framework. Loading metal on this basis allows the metal to enter the defect sites, effectively preventing channel blockage and improving catalyst activity. The purpose of the subsequent ion exchange is to remove metal ions contained in the molecular sieve, restoring the acidic sites of the molecular sieve itself. The shaping purpose is to facilitate the use of the molecular sieve catalyst in a fixed bed. The order of these steps cannot be changed; arbitrarily changing the order may result in the introduction of impurities into the molecular sieve, channel blockage, and damage to the molecular sieve structure.

[0041] Another aspect of the present invention provides a transition metal supported molecular sieve catalyst prepared by the aforementioned method, wherein the transition metal supported molecular sieve catalyst has a transition metal loading of 0.05~10 wt%.

[0042] Another aspect of the present invention provides the application of the aforementioned transition metal supported molecular sieve catalyst in acid-catalyzed reactions, preferably in the preparation of 3-hydroxypropional by the hydration of acrolein.

[0043] Another aspect of the present invention provides a method for preparing 3-hydroxypropanal, comprising: contacting an acrolein solution with the aforementioned transition metal supported molecular sieve catalyst to obtain 3-hydroxypropanal;

[0044] The acrolein solution is prepared by adding 200-2000 ppm hydroquinone to a 5-20 wt% acrolein aqueous solution and mixing them evenly.

[0045] The process conditions for the contact reaction include: a reaction temperature of 45~70℃;

[0046] The mass ratio of acrolein to water in the acrolein aqueous solution is 5:95 to 20:80.

[0047] The mass hourly space velocity (MSV) of the acrolein is 0.1–3 h⁻¹. -1 .

[0048] In the hydration reaction, the transition metal supported molecular sieve catalyst of this invention exhibits reduced activity due to the polymer formed by byproducts covering the catalyst surface. Since this catalyst is a solid acid catalyst, the polymer covering the catalyst surface can be removed by calcination. The catalyst is heated to 100-120°C in an air or oxygen atmosphere, dried for 6-24 hours, and then heated to 500-600°C at a heating rate of 2-10°C / min and calcined for 2-12 hours. After regeneration treatment, the catalyst can restore its catalytic activity.

[0049] The present invention also provides a specific method for preparing 3-hydroxypropanal, comprising the following steps:

[0050] (1) Catalyst loading

[0051] The transition metal supported molecular sieve catalyst is loaded into a fixed-bed hydrogenation reactor with an aspect ratio of 1 to 20.

[0052] (2) Preparation of acrolein raw materials

[0053] Prepare a 5-20 wt% acrolein aqueous solution, add 200-2000 ppm hydroquinone, mix thoroughly to form acrolein raw material.

[0054] (3) Preparation of 3-hydroxypropanal by hydration of acrolein

[0055] The fixed-bed hydrogenation reactor is heated to 45-70°C. Acrolein feedstock is pumped into the upper part of the fixed-bed hydrogenation reactor via a transfer pump, and fed in a spray manner. The feed space velocity for acrolein is 0.1-3 h⁻¹. -1 The reaction liquid flows from the bottom of the reactor into the storage tank.

[0056] The technical solution created by the present invention will be further explained and illustrated below with specific embodiments and experimental examples, so as to enable those skilled in the art to fully understand the present invention. However, the explanation and illustration are not intended to further limit the technical solution created by the present invention. Any simple numerical substitutions and conventional adjustments made on the basis of the present invention are all within the protection scope of the present invention.

[0057] Example 1

[0058] A. Molecular sieve etching

[0059] 100g of MCM-41 molecular sieve was immersed in 400mL of 0.01mol / L tetramethylammonium hydroxide aqueous solution for etching at 90℃ for 4h. After filtration and washing, it was dried at 120℃ for 6h.

[0060] B. Transition metal load

[0061] 100g of etched molecular sieve was immersed in 200mL of 0.025mol / L aluminum chloride aqueous solution at 30℃ for 12h. After filtration, it was dried at 120℃ for 6h and calcined at 500℃ for 6h.

[0062] C. Ion exchange

[0063] 100g of the catalyst prepared in step B was placed in 4000mL of 1mol / L ammonium sulfate and exchanged at 60℃ for 3h. After filtration and washing, the exchange was repeated twice. The catalyst was dried at 120℃ for 6h and calcined at 500℃ for 6h to obtain a transition metal supported molecular sieve catalyst.

[0064] D. Catalyst forming

[0065] 100g of the catalyst from step C was mixed with 50g of boehmite and then bound with 90g of 5wt% nitric acid aqueous solution. The mixture was then molded to obtain a strip-shaped catalyst, dried at 120℃ for 6h, and the strip-shaped catalyst was broken into 1mm particles. The catalyst was then calcined at 500℃ for 6h. The resulting catalyst was designated as catalyst No. 1, with an aluminum loading of 0.05wt%.

[0066] E. Catalyst loading

[0067] 40g of catalyst No. 1 was loaded into a fixed-bed hydrogenation reactor with an aspect ratio of 1;

[0068] F. Preparation of acrolein raw materials

[0069] Prepare a 5wt% acrolein aqueous solution, add 200ppm hydroquinone, and mix thoroughly.

[0070] G. Preparation of 3-hydroxypropanal by hydration of acrolein

[0071] The fixed bed is heated to 45°C, and the raw material is pumped into the upper part of the reactor via a conveying pump, using a spray feeding method. The feed space velocity for acrolein is 3 h⁻¹. -1 The reaction liquid flows from the bottom of the reactor into the storage tank.

[0072] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 1.

[0073] Example 2

[0074] A. Molecular sieve etching

[0075] 100g of MCM-48 molecular sieve was immersed in 100mL of 0.3mol / L tetraethylammonium hydroxide aqueous solution for etching at 50℃ for 8h. After filtration and washing, it was dried at 100℃ for 24h.

[0076] B. Transition metal load

[0077] 100g of etched molecular sieve was immersed in 100mL of 5.0mol / L gallium nitrate nonahydrate aqueous solution at 50℃ for 6h. After filtration, it was dried at 100℃ for 24h and calcined at 600℃ for 3h.

[0078] C. Ion exchange

[0079] 100g of the catalyst prepared in step B was placed in 1000mL of 2mol / L ammonium chloride and exchanged at 90℃ for 1h. After filtration and washing, the exchange was repeated 3 times. The catalyst was dried at 100℃ for 24h and calcined at 600℃ for 3h to obtain a transition metal supported molecular sieve catalyst.

[0080] D. Catalyst forming

[0081] 100g of the catalyst from step C was mixed with 150g of boehmite and then bound with 200g of 5wt% nitric acid aqueous solution. The resulting strip-shaped catalyst was obtained by molding and dried at 100℃ for 24h. The strip-shaped catalyst was then broken into 4mm particles and calcined at 600℃ for 3h. The resulting catalyst was designated as catalyst No. 2, with a gallium loading of 10.0wt%.

[0082] E. Catalyst loading

[0083] 600g of catalyst No. 2 was loaded into a fixed-bed hydrogenation reactor with an aspect ratio of 20;

[0084] F. Preparation of acrolein raw materials

[0085] Prepare a 20wt% acrolein aqueous solution, add 2000ppm hydroquinone, and mix thoroughly.

[0086] G. Preparation of 3-hydroxypropanal by hydration of acrolein

[0087] The fixed bed is heated to 70°C, and the raw material is pumped into the upper part of the reactor via a transfer pump, using a spray feeding method. The feed space velocity for acrolein is 0.1 h⁻¹. -1 The reaction liquid flows from the bottom of the reactor into the storage tank.

[0088] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 1.

[0089] Example 3

[0090] A. Molecular sieve etching

[0091] 100g of SBA-15 molecular sieve was immersed in 200mL of 0.15mol / L tetraethylammonium hydroxide aqueous solution for etching at 60℃ for 6h. After filtration and washing, it was dried at 110℃ for 12h.

[0092] B. Transition metal load

[0093] 100g of etched molecular sieve was immersed in 200mL of 0.5mol / L ammonium hexafluorotitanate aqueous solution at 45℃ for 8h, filtered and washed, dried at 110℃ for 12h, and calcined at 550℃ for 3h.

[0094] C. Ion exchange

[0095] 100g of the catalyst prepared in step B was placed in 3000mL of 1mol / L ammonium nitrate and exchanged at 80℃ for 2h. After filtration and washing, the exchange was repeated 4 times. The catalyst was dried at 110℃ for 12h and calcined at 550℃ for 3h to obtain a transition metal supported molecular sieve catalyst.

[0096] D. Catalyst forming

[0097] 100g of the catalyst from step C was mixed with boehmite at a ratio of 1:1, and then bound with 140g of 5wt% nitric acid aqueous solution. The resulting strip-shaped catalyst was obtained by molding and dried at 110℃ for 12h. The strip-shaped catalyst was then broken into 2mm particles and calcined at 550℃ for 3h. The resulting catalyst was designated as catalyst No. 3, with a titanium loading of 1.53wt%.

[0098] E. Catalyst loading

[0099] 350g of catalyst No. 3 was loaded into a fixed-bed hydrogenation reactor with an aspect ratio of 10.

[0100] F. Preparation of acrolein raw materials

[0101] Prepare a 15wt% acrolein aqueous solution, add 500ppm hydroquinone, and mix thoroughly.

[0102] G. Preparation of 3-hydroxypropanal by hydration of acrolein

[0103] The fixed bed is heated to 50°C, and the raw material is pumped into the upper part of the reactor via a transfer pump, using a spray feeding method. The feed space velocity for acrolein is 0.5 h⁻¹. -1 The reaction liquid flows from the bottom of the reactor into the storage tank.

[0104] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 1.

[0105] Example 4

[0106] A. Molecular sieve etching

[0107] 100g of ZSM-5 molecular sieve was immersed in 200mL of 0.15mol / L tetraethylammonium hydroxide aqueous solution for etching at 60℃ for 6h. After filtration and washing, it was dried at 110℃ for 12h.

[0108] B. Transition metal load

[0109] 100g of etched molecular sieve was immersed in 200mL of 0.5mol / L zinc nitrate aqueous solution at 45℃ for 8h, filtered, dried at 110℃ for 12h, and calcined at 550℃ for 3h.

[0110] C. Ion exchange

[0111] 100g of the catalyst prepared in step B was placed in 3000mL of 1mol / L ammonium nitrate and exchanged at 80℃ for 2h. After filtration and washing, the exchange was repeated 3 times. The catalyst was dried at 110℃ for 12h and calcined at 550℃ for 3h to obtain a transition metal supported molecular sieve catalyst.

[0112] D. Catalyst forming

[0113] 100g of the catalyst from step C was mixed with 100g of boehmite and then bound with 140g of 5wt% nitric acid aqueous solution. The mixture was then molded to obtain a strip-shaped catalyst, dried at 110℃ for 12h, and the strip-shaped catalyst was broken into 2mm particles. The catalyst was then calcined at 550℃ for 3h. The resulting catalyst was designated as catalyst No. 4, with a zinc loading of 2.36wt%.

[0114] Replace the catalyst with catalyst No. 4 and repeat steps E, F, and G of Example 3.

[0115] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 1.

[0116] Example 5

[0117] A. Molecular sieve etching

[0118] 100g of Y molecular sieve was immersed in 200mL of 0.15mol / L tetraethylammonium hydroxide aqueous solution for etching at 60℃ for 6h. After filtration and washing, it was dried at 110℃ for 12h.

[0119] B. Transition metal load

[0120] 100g of etched molecular sieve was immersed in 200mL of 0.5mol / L zirconium sulfate aqueous solution at 45℃ for 8h. After filtration, it was dried at 110℃ for 12h and calcined at 550℃ for 3h.

[0121] C. Ion exchange

[0122] 100g of the catalyst prepared in step B was placed in 3000mL of 1mol / L ammonium nitrate and exchanged at 80℃ for 2h. After filtration and washing, the exchange was repeated 3 times. The catalyst was dried at 110℃ for 12h and calcined at 550℃ for 3h to obtain a transition metal supported molecular sieve catalyst.

[0123] D. Catalyst forming

[0124] 100g of the catalyst from step C was mixed with 100g of boehmite and then bound with 140g of 5wt% nitric acid aqueous solution. The mixture was then molded into strip-shaped catalysts, dried at 110℃ for 12h, and then crushed into 2mm particles. The catalysts were calcined at 550℃ for 3h. The resulting catalyst was designated as catalyst No. 5, with a zirconium loading of 3.82wt%.

[0125] Replace the catalyst with catalyst No. 5 and repeat steps E, F, and G of Example 3.

[0126] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 1.

[0127] Table 1. Acrolein conversion and 3-hydroxypropanal selectivity of the catalysts used in Examples 1-5

[0128] No. 1 42 91 No. 2 90 47 No. 3 81 84 No. 4 84 85 No. 5 87 83

[0129] Comparative Example 1

[0130] Y molecular sieve and pseudoboehmite were mixed in a 1:1 ratio and then bonded together with 0.7 times the powder mass of 5wt% nitric acid aqueous solution. The resulting strip-shaped catalyst was obtained by molding equipment, dried at 110℃ for 12h, and then crushed into 1mm particles and calcined at 550℃ for 3h. The resulting catalyst was designated as catalyst D1.

[0131] Replace the catalyst with catalyst D1 and repeat steps E, F, and G of Example 3.

[0132] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 2.

[0133] Comparative Example 2

[0134] A. Ion exchange

[0135] 100g of Y molecular sieve was placed in 3000mL of 1mol / L ammonium nitrate and exchanged at 80℃ for 2h. After filtration and washing, the exchange was repeated three times. The catalyst was dried at 110℃ for 12h and calcined at 550℃ for 3h to obtain the hydrogen-form molecular sieve catalyst.

[0136] B. Catalyst Formation

[0137] The catalyst was mixed with boehmite at a ratio of 1:1, and then bound with 140g of 5wt% nitric acid aqueous solution. The resulting strip-shaped catalyst was obtained by molding equipment, dried at 110℃ for 12h, and then crushed into 1mm particles and calcined at 550℃ for 3h. The resulting catalyst was designated as catalyst D2.

[0138] Replace the catalyst with catalyst D2 and repeat steps E, F, and G of Example 3.

[0139] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 2.

[0140] Comparative Example 3

[0141] A. Transition metal load

[0142] 100 Y molecular sieve was impregnated in 200 mL of 0.5 mol / L zirconium sulfate aqueous solution at 45 °C for 8 h. After filtration, it was dried at 110 °C for 12 h and then calcined at 550 °C for 3 h.

[0143] B. Ion exchange

[0144] 100g of the catalyst prepared in step B was placed in 3000mL of 1mol / L ammonium nitrate and exchanged at 80℃ for 2h. After filtration and washing, the exchange was repeated three times. The catalyst was dried at 110℃ for 12h and calcined at 550℃ for 3h to obtain a transition metal supported molecular sieve catalyst.

[0145] C. Catalyst Formation

[0146] The catalyst was mixed with boehmite at a ratio of 1:1, and then bound with 140g of 5wt% nitric acid aqueous solution. The resulting strip-shaped catalyst was obtained by molding equipment, dried at 110℃ for 12h, and then crushed into 1mm particles and calcined at 550℃ for 3h. The resulting catalyst was designated as catalyst D3, with a zirconium loading of 2.63wt%.

[0147] Replace the catalyst with D3 catalyst and repeat steps E, F, and G of Example 3.

[0148] The products were analyzed using gas chromatography and other methods, and their catalytic performance was calculated. The results are shown in Table 2.

[0149] Table 2. Acrolein conversion and 3-hydroxypropanal selectivity of the catalysts used in Comparative Examples 1-3

[0150] D1 32 26 D2 65 69 D3 77 83

[0151] As shown in Tables 1 and 2, comparative example D1 represents Y molecular sieve without ammonium exchange, while D2 represents Y molecular sieve with ammonium exchange. The data shows that ammonium exchange can improve the catalytic activity of the catalyst. D3 represents molecular sieve without organic base etching. During the loading process, metal ions enter the molecular sieve channels and accumulate within them, leading to blockage of some molecular sieve channels and reduced catalyst activity. In the embodiments, organic base etching is used to expand the molecular sieve channel size, forming a multi-level channel structure. Then, by loading the transition metal, the catalytic activity of the catalyst is effectively improved, resulting in a highly efficient transition metal-supported molecular sieve catalyst.

[0152] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0153] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions may be made without departing from the spirit and scope of the invention, and substantial equivalents may be used.

[0154] The elements of the embodiments described are alternatives. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. The application of metal-supported molecular sieve catalysts in the hydration of acrolein to prepare 3-hydroxypropional, characterized in that, The application includes providing a method for preparing the metal-supported molecular sieve catalyst: Molecular sieves are immersed in an organic base solution with a concentration of 0.01~0.3mol / L for etching. The ratio of molecular sieve to organic base solution is 100g:100~400mL. The etching temperature is 50~90℃, and the etching time is 4~8h. After filtration and washing, the sieves are dried at 100~120℃ for 6~24h to form a molecular sieve with multi-level channels and defects. The organic base solution is selected from tetramethylammonium hydroxide solution and / or tetraethylammonium hydroxide solution. The molecular sieves include any one or a combination of two or more of MCM-41, MCM-48, SBA-15, ZSM-5, and Y-type molecular sieves. The etched molecular sieve is immersed in a metal salt solution, then dried and calcined, so that the metal is loaded into the multi-level channels and defect sites contained in the molecular sieve; the metal salt in the metal salt solution is selected from any one or more combinations of metal halide, metal sulfate, metal nitrate, and metal ammonium salt, and the metal element is selected from any one or more combinations of aluminum, titanium, gallium, and zirconium. The calcined molecular sieve was subjected to ion exchange to obtain a metal-supported molecular sieve catalyst.

2. The application according to claim 1, characterized in that, The preparation method of the metal-supported molecular sieve catalyst includes: immersing an etched molecular sieve in a metal salt solution with a concentration of 0.025~5 mol / L, wherein the mass ratio of molecular sieve to metal salt solution is 1:1~2, the immersion temperature is 30~50℃, the immersion time is 6~12h, the sieve is filtered, dried at 100~120℃ for 6~24h, and calcined at 500~600℃ for 3~6h to obtain the metal-supported molecular sieve catalyst.

3. The application according to claim 1, characterized in that, The preparation method of the metal-supported molecular sieve catalyst includes: placing the metal-supported molecular sieve catalyst in an ammonium salt with a concentration of 1~2 mol / L, wherein the mass ratio of molecular sieve to ammonium salt is 1:10~30, exchanging the catalyst at 60~90℃ for 1~3 h, filtering and washing, repeating the exchange step 2~4 times, drying the catalyst at 100~120℃ for 12~24 h, and calcining it at 500~600℃ for 3~6 h; wherein the ammonium salt includes any one or more of ammonium sulfate, ammonium chloride, and ammonium nitrate.

4. The application according to claim 1, characterized in that, The preparation method of the metal-supported molecular sieve catalyst further includes: mixing the metal-supported molecular sieve catalyst with boehmite at a mass ratio of 1:0.5~1.5, and binding the resulting mixed powder with a 5wt% nitric acid aqueous solution. The mass ratio of the mixed powder to the 5wt% nitric acid aqueous solution is 1:0.6~0.

8. The catalyst is then obtained as a strip through a molding device, dried at 100-120℃ for 12~24h, and then the strip catalyst is crushed into 1~4 mm particles and calcined at 500~600℃ for 3~6h.

5. The application according to any one of claims 1-4, characterized in that, The metal loading in the metal-supported molecular sieve catalyst is 0.05~10wt%.

6. A method for preparing 3-hydroxypropanal, characterized in that, include: Acrolein solution is contacted with and reacted with the metal-supported molecular sieve catalyst according to any one of claims 1-5 to obtain 3-hydroxypropionaldehyde; The acrolein solution is prepared by adding 200-2000 ppm hydroquinone to a 5-20 wt% acrolein aqueous solution and mixing them evenly. The reaction temperature is 45~70℃; The mass hourly space velocity (MSV) of the acrolein is 0.1–3 h⁻¹. -1 .