Lanthanide metal modified strong-acidity cation exchange resin, preparation method thereof and application of cation exchange resin in synthesis of hydroxybutyl acrylate

Abstract

The invention belongs to the technical field of catalytic synthesis, and relates to lanthanide series metal modified strong-acid cation exchange resin, a preparation method thereof and application of the cation exchange resin in hydroxybutyl acrylate synthesis. Comprising the following steps: taking styrene and 1, 4-butanediol diacrylate as polymeric monomers, adding a cross-linking agent, an initiator and a pore-foaming agent, and polymerizing to obtain polystyrene resin; then removing the pore-foaming agent in the polystyrene resin to obtain polystyrene porous resin; introducing a sulfonic acid group into the polystyrene porous resin through sulfonation reaction to obtain strong acid cation exchange resin; and adding lanthanide metal salt into the strong acid cation exchange resin to enable the strong acid cation exchange resin to load lanthanide metal, thereby obtaining the catalyst. The lanthanide series metal modified strong acid cation exchange resin used as a catalyst has the advantages of mild reaction conditions, high selectivity, small corrosion to equipment, capability of effectively avoiding side reactions, easiness in separation from products by conventional means and the like.

Description

Technical Field

[0001] This invention belongs to the field of catalytic synthesis technology, and relates to lanthanide metal-modified strong acid cation exchange resin, its preparation method, and its application in the synthesis of hydroxybutyl acrylate. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Hydroxybutyl acrylate (HBacrylate) is a high-performance acrylate compound. Due to the presence of both highly reactive propylene and hydroxyl groups, it exhibits extremely active chemical properties. With its excellent adhesion, superior scratch resistance, and good compatibility, HBacrylate has been widely used in automotive coatings, architectural coatings, adhesives, and photosensitive resins, demonstrating broad application prospects and significant industrial value. In the production of HBacrylate, traditional methods often use concentrated sulfuric acid as a catalyst, catalyzing the esterification and dehydration reaction of an acid and an alcohol. However, while concentrated sulfuric acid is inexpensive and readily available, it has several drawbacks as a catalyst. Firstly, concentrated sulfuric acid is highly corrosive to production equipment, increasing maintenance costs. Secondly, since both the reactants and the catalyst are acidic, a complex neutralization process is usually required after the reaction to adjust the product's pH to neutral, and this process also generates salt waste, which does not meet environmental protection requirements. Furthermore, the esterification and dehydration process for producing HBacrylate generates water, which is difficult to completely remove.

[0004] To improve the above shortcomings, some studies have proposed an alternative transesterification reaction, namely, using methyl acrylate and 1,4-butanediol as raw materials to generate 4-hydroxybutyl acrylate under Lewis acid catalysis such as organotin / titanium, as shown in chemical reaction formula 1. However, such catalysts are difficult to effectively separate and remove from the reaction system, resulting in difficult catalyst recovery and complex product purification. In recent years, with the proposal and development of green chemistry, people have paid more attention to heterogeneous catalysts. Among them, ion exchange resins, as a heterogeneous catalyst with unique structure and function, have received widespread attention. However, although existing strong acid cation exchange resins (such as sulfonated polystyrene resin) can replace concentrated sulfuric acid, they face two major bottlenecks when catalyzing transesterification reactions: (1) the sulfonic acid group (-SO3H) has a low degree of dissociation in non-aqueous systems, resulting in insufficient utilization of active sites; (2) the resin is prone to swelling in high-temperature organic solvents, resulting in resin particle fragmentation and poor skeletal structure stability. Furthermore, a side reaction easily occurs during the formation of hydroxybutyl 4-acrylate, producing 1,4-butanediol diacrylate, as shown in chemical reaction formula 2. This byproduct has a boiling point similar to that of hydroxybutyl 4-acrylate, making it difficult to separate using conventional methods. This leads to a decrease in the purity of hydroxybutyl 4-acrylate and affects the downstream polymerization performance. Therefore, developing a highly active, high-temperature resistant, easily separable, and selectively inhibitory heterogeneous catalyst for the formation of the byproduct 1,4-butanediol diacrylate has become a core challenge in the green synthesis of hydroxybutyl 4-acrylate.

[0005] Chemical reaction formula 1:

[0006] Chemical reaction formula 2: Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a lanthanide-modified strong acid cation exchange resin, its preparation method, and its application in the synthesis of hydroxybutyl acrylate. Using this lanthanide-modified strong acid cation exchange resin as a catalyst offers numerous advantages, including mild reaction conditions, high selectivity, low corrosiveness to equipment, effective avoidance of side reactions, and easy separation from the product using conventional methods.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, a method for preparing a lanthanide-modified strong acid cation exchange resin includes the following steps: Polystyrene porous resin was obtained by polymerization using styrene and 1,4-butanediol diacrylate as polymerizing monomers and adding crosslinking agent, initiator and porogen. Sulfonation reaction is used to introduce sulfonic acid groups into the polystyrene porous resin to obtain a strong acid cation exchange resin. Lanthanide metal salts are added to the strong acid cation exchange resin to load the lanthanide metals onto the strong acid cation exchange resin, thus obtaining the product.

[0009] Secondly, a lanthanide-modified strong acid cation exchange resin is obtained by the preparation method described in the first aspect of this invention.

[0010] Thirdly, the application of the lanthanide metal-modified strong acid cation exchange resin described in the second aspect of the present invention as a catalyst in the synthesis of hydroxybutyl acrylate.

[0011] The beneficial effects of this invention are as follows: (1) The lanthanide metal-modified strong acid cation exchange resin provided by the present invention adds 1,4-butanediol diacrylate as a comonomer during the preparation of polystyrene porous resin. This not only enhances the resin skeleton structure through crosslinking and improves its stability in high-temperature organic solvents, but also, since this comonomer is a byproduct of hydroxybutyl acrylate, adding it to the resin structure can inhibit the formation of 1,4-butanediol diacrylate in the catalytic reaction, thereby improving the selectivity of the target product (hydroxybutyl acrylate).

[0012] (2) In this invention, lanthanide metal salts are loaded onto strong acid cation exchange resins to modify the strong acid cation exchange resins. Lanthanide metals have high charge density and can form Brønsted-Lewis dual active sites with sulfonic acid groups, which significantly improves the catalytic performance of the catalyst and thus increases the yield of the target product (hydroxybutyl 4-acrylate).

[0013] (3) The lanthanide metal-modified strong acid cation exchange resin provided by the present invention is used as a catalyst in the synthesis of hydroxybutyl acrylate. Since the resin is not miscible with the reaction solution, it is easy to separate from the product by conventional means. Therefore, the recycling method is simple, easy to recycle, and reduces production costs. Detailed Implementation

[0014] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0015] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0016] Given that existing catalysts struggle to simultaneously achieve high activity, high temperature resistance, easy separation, and high selectivity in the synthesis of hydroxybutyl acrylate, this invention proposes a lanthanide-modified strong acid cation exchange resin, its preparation method, and its application in the synthesis of hydroxybutyl acrylate.

[0017] A typical embodiment of the present invention provides a method for preparing a lanthanide metal-modified strong acid cation exchange resin, comprising the following steps: Polystyrene porous resin was obtained by polymerization using styrene and 1,4-butanediol diacrylate as polymerizing monomers and adding crosslinking agent, initiator and porogen. Sulfonation reaction is used to introduce sulfonic acid groups into the polystyrene porous resin to obtain a strong acid cation exchange resin. Lanthanide metal salts are added to the strong acid cation exchange resin to load the lanthanide metals onto the strong acid cation exchange resin, thus obtaining the product.

[0018] In the preparation of polystyrene porous resin, the present invention adds 1,4-butanediol diacrylate as a comonomer, which can not only improve the high-temperature stability of the final resin product and enhance its recycling performance through crosslinking, but also suppress the side reactions of hydroxybutyl acrylate synthesis and increase the selectivity of hydroxybutyl acrylate.

[0019] Meanwhile, by introducing sulfonic acid groups and loading lanthanide metals, this invention can form Brønsted-Lewis dual active sites, thereby improving catalytic performance and increasing the yield of hydroxybutyl acrylate.

[0020] In some embodiments, the polymerization is suspension polymerization. Suspension polymerization refers to the process of free radical polymerization in which monomers containing an initiator are suspended in water as droplets. The polystyrene resin prepared by this process is granular with a high specific surface area, which is beneficial for increasing the introduction of sulfonic acid groups, thereby improving its catalytic performance. Specifically, in suspension polymerization, styrene, 1,4-butanediol diacrylate, a crosslinking agent, an initiator, and a pore-forming agent are mixed uniformly as an oil phase, and the oil phase is added to an aqueous phase containing a dispersant and a polymerization inhibitor, and the polymerization reaction is initiated by heating. More specifically, the dispersant can be polyvinyl alcohol. More specifically, the polymerization inhibitor can be methylene blue. In the aqueous phase, the mass ratio of water, dispersant, and polymerization inhibitor is 100:(10~20):(0.1~0.5). Specifically, in suspension polymerization, the mass ratio of the aqueous phase to the oil phase is 10:(5~8).

[0021] The crosslinking agent described in this invention can be divinylbenzene. The porogen described in this invention can be n-heptane. The initiator described in this invention is an oil-soluble initiator, such as organic peroxides like benzoyl peroxide (BPO) or azo dyes like azobisisobutyronitrile (AIBN). The polymerization temperature is related to the decomposition temperature of the initiator. For example, when BPO is used as the initiator, the polymerization temperature is 80-85°C; when AIBN is used as the initiator, the polymerization temperature is 65-75°C.

[0022] In some embodiments, the mass ratio of styrene, 1,4-butanediol diacrylate, and crosslinking agent is 2:(1~2):(0.5~1.5).

[0023] In some embodiments, the mass ratio of styrene, porogen, and initiator is 30:(40~150):(1.0~1.5).

[0024] In some embodiments, the polymerization time is 5 to 8 hours. Specifically, when BPO is used as the initiator, the temperature is first raised to 65 to 75°C and reacted for 1.5 to 2.5 hours, and then the temperature is raised to 80 to 85°C and reacted for 3.5 to 4.5 hours.

[0025] The sulfonation process involves swelling the polystyrene porous resin, adding concentrated sulfuric acid or fuming sulfuric acid with a mass fraction of not less than 70%, and heating to carry out the reaction. In some embodiments, N-methyl-2-pyrrolidone is used as a solvent during the sulfonation reaction. Specifically, the mass ratio of polystyrene porous resin to N-methyl-2-pyrrolidone is 1:(3~5). In conventional polystyrene resins, halogenated solvents such as dichloroethane are generally used as swelling agents. Since this invention uses 1,4-butanediol diacrylate as a comonomer, using N-methyl-2-pyrrolidone as a solvent can also fully swell the polystyrene porous resin, reducing the health impact on workers. Specifically, the sulfonation reaction temperature is 75~85 °C, and the sulfonation reaction time is 1~3 hours. After the sulfonation reaction, washing with water is generally required to remove free sulfuric acid. When using concentrated sulfuric acid with a mass fraction of 98% for the sulfonation reaction, the mass ratio of polystyrene porous resin to concentrated sulfuric acid is 1:(1~5).

[0026] In some embodiments, n-heptane is added as a dehydrating agent during the sulfonation reaction. The addition of n-heptane, through azeotropic dehydration, shifts the sulfonation equilibrium to the right, effectively increasing the grafting amount of sulfonic acid groups. Specifically, the mass ratio of polystyrene porous resin to dehydrating agent is 1:(0.5~2).

[0027] The lanthanide metal salts described in this invention refer to compounds that are soluble in water and whose cations are lanthanide metal ions. The lanthanide metals can be cerium, erbium, ytterbium, etc., meaning the lanthanide metal salts can be cerium salts, erbium salts, ytterbium salts, etc., and their anions can be nitrate ions, chloride ions, sulfate ions, etc. In some embodiments, the lanthanide metal salt is a ytterbium salt. Studies have shown that different lanthanide metals have different catalytic effects, with cerium < erbium < ytterbium. That is, when the strong acid cation exchange resin is modified with lanthanide metals, the catalytic effect of the lanthanide-modified strong acid cation exchange resin is better.

[0028] In some embodiments, an aqueous solution of lanthanide metal salt is added to a strong acid cation exchange resin, heated to 55-65°C, and allowed to stand for 10-14 hours. Specifically, the concentration of lanthanide metal ions in the aqueous solution of lanthanide metal salt is 0.5-1 mol / L. Specifically, the solid-liquid ratio of the strong acid cation exchange resin to the aqueous solution of lanthanide metal salt is 1:15-25, g / mL.

[0029] In another embodiment of the present invention, a lanthanide metal-modified strong acid cation exchange resin is provided, which is obtained by the above preparation method.

[0030] A third embodiment of the present invention provides the application of the above-mentioned lanthanide metal-modified strong acid cation exchange resin as a catalyst in the synthesis of hydroxybutyl acrylate.

[0031] In some embodiments, the lanthanide-modified strong acid cation exchange resin is added to a mixture of acrylate and 1,4-butanediol, and the mixture is heated to 80-100°C and reacted for 6-10 hours. The acrylate described in this invention can be methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, etc. Specifically, the molar ratio of acrylate to 1,4-butanediol is 1:2.5-3.5. Specifically, the amount of lanthanide-modified strong acid cation exchange resin added is 0.1-1.0% of the total mass of acrylate and 1,4-butanediol, preferably 0.4-0.6%.

[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0033] Example 1: 1. Preparation of porous polystyrene matrix: (1) Add 500g of deionized water, 15g of polyvinyl alcohol (dispersant) and 0.2g of methylene blue (polymerization inhibitor) to the reaction vessel, stir at 400 rpm and heat to 60°C to mix evenly, forming a polyvinyl alcohol solution as the aqueous phase for later use.

[0034] (2) Mix 100g styrene, 60g 1,4-butanediol diacrylate, 40g divinylbenzene (crosslinking agent), 2g benzoyl peroxide and 80g porogen (n-heptane), stir at 300 rpm to dissolve evenly, and form a polymerization product as the oil phase for later use.

[0035] (3) 160g of oil phase was added to 200g of aqueous phase, heated to 70℃ and reacted for 2 hours, then heated to 80℃ and kept at that temperature for 4 hours. After cooling to room temperature, the mixture was filtered, dried and sieved to obtain polystyrene porous resin.

[0036] 2. Preparation of strong acid cation exchange resin (sulfonation reaction): Add 50g of the polystyrene porous resin prepared in step 1 and 150g of N-methyl-2-pyrrolidone to a reaction vessel equipped with a water separator and stir until the resin is fully swollen. To remove the byproduct water from the system, add 50g of n-heptane as a dehydrating agent. Add 100g of concentrated sulfuric acid (98% by mass) while stirring. Gradually increase the temperature to 80℃ and maintain it for 2 hours. After cooling to room temperature, wash with deionized water until neutral and dry to obtain a strong acid cation exchange resin.

[0037] 3. Preparation of lanthanide-modified strong acid cation exchange resins (lanthanide modification): A 0.5 mol / L solution of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) was prepared by dissolving it in distilled water and added to the strong acid cation exchange resin obtained in step 2, with a solid-liquid ratio of 1:20 (g / mL). The reaction vessel was allowed to stand at 60℃ for 12 h, cooled to room temperature, filtered, and then transferred to an 80℃ oven for drying to obtain the modified strong acid cation exchange resin catalyst, which is the lanthanide metal-modified strong acid cation exchange resin.

[0038] 4. Catalytic synthesis of hydroxybutyl 4-acrylate The molar ratio of methyl acrylate to 1,4-butanediol was 1:3. 25.83g of methyl acrylate, 81.09g of 1,4-butanediol, and 0.5g of catalyst (lanthanide metal-modified strong acid cation exchange resin prepared in step 3) were added to 250ml round-bottom flasks respectively. The reaction temperature was 90℃ and the reaction time was 6h. Example 2: 1. Preparation of porous polystyrene matrix: (1) Add 500g of deionized water, 15g of polyvinyl alcohol (dispersant) and 0.2g of methylene blue (polymerization inhibitor) to the reaction vessel, stir at 400 rpm and heat to 60°C to mix evenly, forming a polyvinyl alcohol solution as the aqueous phase for later use.

[0039] (2) Mix 100g styrene, 60g 1,4-butanediol diacrylate, 40g divinylbenzene (crosslinking agent), 2g benzoyl peroxide and 80g porogen (n-heptane), stir at 300 rpm to dissolve evenly, and form a polymerization product as the oil phase for later use.

[0040] (3) 160g of oil phase was added to 200g of aqueous phase, heated to 70℃ and reacted for 2 hours, then heated to 80℃ and kept at that temperature for 4 hours. After cooling to room temperature, the mixture was filtered, dried and sieved to obtain polystyrene porous resin.

[0041] 2. Preparation of strong acid cation exchange resin (sulfonation reaction): Add 50g of the polystyrene porous resin prepared in step 1 and 150g of N-methyl-2-pyrrolidone to a reaction vessel equipped with a water separator and stir until the resin is fully swollen. To remove the byproduct water from the system, add 50g of n-heptane as a dehydrating agent. Add 100g of concentrated sulfuric acid (98% by mass) while stirring. Gradually increase the temperature to 80℃ and maintain it for 2 hours. After cooling to room temperature, wash with deionized water until neutral and dry to obtain a strong acid cation exchange resin.

[0042] 3. Preparation of lanthanide-modified strong acid cation exchange resins (lanthanide modification): A 0.5 mol / L solution of erbium nitrate hexahydrate (Er(NO3)3·6H2O) was prepared by dissolving it in distilled water and added to the strong acid cation exchange resin obtained in step 2, with a solid-liquid ratio of 1:20 g / mL. The reaction vessel was allowed to stand at 60°C for 12 h, cooled to room temperature, filtered, and then transferred to an 80°C oven for drying to obtain the modified strong acid cation exchange resin catalyst, which is a lanthanide metal-modified strong acid cation exchange resin.

[0043] 4. Catalytic synthesis of hydroxybutyl 4-acrylate The molar ratio of methyl acrylate to 1,4-butanediol was 1:3. 25.83g of methyl acrylate, 81.09g of 1,4-butanediol, and 0.5g of catalyst (lanthanide metal-modified strong acid cation exchange resin prepared in step 3) were added to 250ml round-bottom flasks respectively. The reaction temperature was 90℃ and the reaction time was 6h.

[0044] Example 3: 1. Preparation of porous polystyrene matrix: (1) Add 500g of deionized water, 15g of polyvinyl alcohol (dispersant) and 0.2g of methylene blue (polymerization inhibitor) to the reaction vessel, stir at 400 rpm and heat to 60°C to mix evenly, forming a polyvinyl alcohol solution as the aqueous phase for later use.

[0045] (2) Mix 100g styrene, 60g 1,4-butanediol diacrylate, 40g divinylbenzene (crosslinking agent), 2g benzoyl peroxide and 80g porogen (n-heptane), stir at 300 rpm to dissolve evenly, and form a polymerization product as the oil phase for later use.

[0046] (3) 160g of oil phase was added to 200g of aqueous phase, heated to 70℃ and reacted for 2 hours, then heated to 80℃ and kept at that temperature for 4 hours. After cooling to room temperature, the mixture was filtered, dried and sieved to obtain polystyrene porous resin.

[0047] 2. Preparation of strong acid cation exchange resin (sulfonation reaction): Add 50g of the polystyrene porous resin prepared in step 1 and 150g of N-methyl-2-pyrrolidone to a reaction vessel equipped with a water separator and stir until the resin is fully swollen. To remove the byproduct water from the system, add 50g of n-heptane as a dehydrating agent. Add 100g of concentrated sulfuric acid (98% by mass) while stirring. Gradually increase the temperature to 80℃ and maintain it for 2 hours. After cooling to room temperature, wash with deionized water until neutral and dry to obtain a strong acid cation exchange resin.

[0048] 3. Preparation of lanthanide-modified strong acid cation exchange resins (lanthanide modification): A 0.5 mol / L solution of ytterbium nitrate pentahydrate (Yb(NO3)3·5H2O) hexahydrate was prepared by dissolving it in distilled water and added to the strong acid cation exchange resin obtained in step 2, with a solid-liquid ratio of 1:20 g / mL. The reaction vessel was allowed to stand at 60°C for 12 h, cooled to room temperature, filtered, and then transferred to an 80°C oven for drying to obtain the modified strong acid cation exchange resin catalyst, which is a lanthanide metal-modified strong acid cation exchange resin.

[0049] 4. Catalytic synthesis of hydroxybutyl 4-acrylate The molar ratio of methyl acrylate to 1,4-butanediol was 1:3. 25.83g of methyl acrylate, 81.09g of 1,4-butanediol, and 0.5g of catalyst (lanthanide metal-modified strong acid cation exchange resin prepared in step 3) were added to 250ml round-bottom flasks respectively. The reaction temperature was 90℃ and the reaction time was 6h.

[0050] Comparative Example 1: The molar ratio of methyl acrylate to 1,4-butanediol was 1:3. 25.83g of methyl acrylate and 81.09g of 1,4-butanediol were used. The catalyst was concentrated sulfuric acid (mass fraction of 98%), and the amount added was 0.8 mol% of methyl acrylate. The reaction temperature was 90℃ and the reaction time was 6h.

[0051] Comparative Example 2: The molar ratio of methyl acrylate to 1,4-butanediol was 1:3. 25.83g of methyl acrylate and 81.09g of 1,4-butanediol were used. The catalyst was dioctyltin oxide, which was added at 0.8 mol% of methyl acrylate. The reaction temperature was 90℃ and the reaction time was 6h.

[0052] Comparative Example 3: 1. Preparation of porous polystyrene matrix: (1) Add 500g of deionized water, 15g of polyvinyl alcohol (dispersant) and 0.2g of methylene blue (polymerization inhibitor) to the reaction vessel, stir at 400 rpm and heat to 60°C to mix evenly, forming a polyvinyl alcohol solution as the aqueous phase for later use.

[0053] (2) Mix 100g styrene, 40g divinylbenzene (crosslinking agent), benzoyl peroxide (n-heptane) and pore-forming agent, stir at 300 rpm to dissolve evenly, and form a polymerization product as an oil phase for later use.

[0054] (3) 160g of oil phase was added to 200g of aqueous phase, heated to 70℃ and reacted for 2 hours, then heated to 80℃ and kept at that temperature for 4 hours. After cooling to room temperature, the pore-forming agent was recovered, dried and sieved to obtain polystyrene porous resin.

[0055] 2. Preparation of strong acid cation exchange resin (sulfonation reaction): Add 50g of the polystyrene porous resin prepared in step 1 and 150g of N-methyl-2-pyrrolidone to a reaction vessel equipped with a water separator and stir until the resin is fully swollen. To remove the byproduct water from the system, add 50g of n-heptane as a dehydrating agent. Add 100g of concentrated sulfuric acid (98% by mass) while stirring. Gradually increase the temperature to 80℃ and maintain it for 2 hours. After cooling to room temperature, wash with deionized water until neutral and dry to obtain a strong acid cation exchange resin.

[0056] Catalytic synthesis of 3,4-hydroxybutyl acrylate The molar ratio of methyl acrylate to 1,4-butanediol was 1:3. 25.83g of methyl acrylate, 81.09g of 1,4-butanediol, and 0.5g of the strong acid cation exchange resin prepared in step 2 were added to 250ml round-bottom flasks respectively. The reaction temperature was 90℃ and the reaction time was 6h.

[0057] The results of each embodiment and comparative example are shown in Table 1: Table 1 Comparison of transesterification reaction data

[0058] As shown in Table 1 above, the comparison of the results of Comparative Examples 1-2 and Examples 1-3 shows that, compared with commonly used transesterification catalysts such as concentrated sulfuric acid and dioctyltin oxide, the modified strong acid cation exchange resin has significantly improved selectivity and yield.

[0059] The results of Comparative Example 3 show that, firstly, compared with Comparative Examples 1-2, when 1,4-butanediol diacrylate was not added for polymerization and lanthanide metal modification was not used, its catalytic effect was basically similar to that of commonly used transesterification catalysts such as concentrated sulfuric acid and dioctyltin oxide. However, after adding 1,4-butanediol diacrylate for polymerization and using lanthanide metal modification, i.e. Examples 1-3, the selectivity and yield of its catalytic 4-hydroxybutyl acrylate synthesis reaction were significantly improved.

[0060] Furthermore, a comparison of the results from Examples 1-3 shows that different lanthanide metal modifications have different catalytic effects. Overall, the catalytic effect of cerium modification is < the catalytic effect of erbium modification < the catalytic effect of ytterbium modification, meaning that the ytterbium-modified strong acid cation exchange resin has a better catalytic effect on the synthesis reaction of hydroxybutyl 4-acrylate.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a lanthanide metal-modified strong acid cation exchange resin, characterized in that, The method comprises the following steps: The polystyrene porous resin is obtained by polymerization with styrene and 1,4-butanediol diacrylate as polymerization monomers, and by adding a crosslinking agent, an initiator and a pore-forming agent; The sulfonic acid group is introduced into the polystyrene porous resin through a sulfonation reaction to obtain a strong acid cation exchange resin; The lanthanide metal salt is added to the strong acid cation exchange resin, so that the strong acid cation exchange resin is loaded with the lanthanide metal.

2. The production method according to claim 1, wherein The polymerization is suspension polymerization; preferably, in the suspension polymerization, styrene, 1,4-butanediol diacrylate, a crosslinking agent, an initiator and a pore-forming agent are uniformly mixed as an oil phase, and the oil phase is added to an aqueous phase containing a dispersant and a polymerization inhibitor, and the polymerization is initiated by heating; preferably, the dispersant can be polyvinyl alcohol; preferably, the polymerization inhibitor is methylene blue; preferably, in the aqueous phase, the mass ratio of water, the dispersant and the polymerization inhibitor is 100:(10-20):(0.1-0.5); preferably, in the suspension polymerization, the mass ratio of the aqueous phase to the oil phase is 10:(5-8).

3. The production method according to claim 1, wherein The mass ratio of styrene, 1,4-butanediol diacrylate and the crosslinking agent is 2:(1-2):(0.5-1.5); Or, the mass ratio of styrene, the pore-forming agent and the initiator is 30:(40-150):(1.0-1.5); Or, the polymerization time is 5-8 hours.

4. The production method according to claim 1, wherein the step of In the sulfonation reaction process, N-methyl-2-pyrrolidone is used as a solvent; preferably, the mass ratio of the polystyrene porous resin to N-methyl-2-pyrrolidone is 1:(3-5).

5. The preparation method of claim 1, wherein, in the sulfonation reaction process, n-heptane is added as a water-carrying agent; preferably, the mass ratio of the polystyrene porous resin to the water-carrying agent is 1:(0.5-2).

6. The production method according to claim 1, wherein The lanthanide metal salt is a ytterbium salt.

7. The production method according to claim 1, wherein the production method is characterized by The aqueous solution of the lanthanide metal salt is added to the strong acid cation exchange resin, heated to 55-65℃, and left to stand for 10-14 hours; preferably, the concentration of the lanthanide metal ion in the aqueous solution of the lanthanide metal salt is 0.5-1 mol / L; preferably, the solid-liquid ratio of the strong acid cation exchange resin to the aqueous solution of the lanthanide metal salt is 1:15-25, g / mL.

8. A lanthanide-modified strongly acidic cation exchange resin characterized by, The preparation method is obtained by any one of claims 1-7.

9. The lanthanide metal modified strong acid cation exchange resin of claim 8 as a catalyst in the synthesis of hydroxybutyl acrylate.

10. The use according to claim 9, wherein the compound is ###00003### or a pharmaceutically acceptable salt thereof. The lanthanide metal modified strong acid cation exchange resin is added to a mixture of acrylate and 1,4-butanediol, heated to 80-100℃, and reacted for 6-10 hours; preferably, the molar ratio of acrylate to 1,4-butanediol is 1:2.5-3.5; preferably, the addition amount of the lanthanide metal modified strong acid cation exchange resin is 0.1-1.0% of the total mass of acrylate and 1,4-butanediol, preferably 0.4-0.6%.

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