Ion exchange resin for ester exchange as well as preparation method and application of ion exchange resin

Abstract

The invention discloses ion exchange resin for ester exchange as well as a preparation method and application of the ion exchange resin. The ion exchange resin for ester exchange has a structural general formula shown in a formula (1): # imgabs0 #, the # imgabs1 # is an ion exchange resin matrix, and R is selected from at least one of hydrogen or C1-C10 saturated or unsaturated aliphatic groups; x-is an anion or an anionic group; the ion exchange resin for ester exchange is provided with spherical or sphere-like pore channels. The ion exchange resin for transesterification shows high activity and stability in a reaction for preparing dimethyl carbonate through transesterification, and the preparation method provided by the invention is simple and feasible and can provide reference for preparing other catalysts with higher performance.

Description

Technical Field

[0001] The present invention relates to the technical field of ion exchange resins, and particularly to an ion exchange resin for transesterification, a preparation method thereof and an application thereof. Background Art

[0002] As a new type of green basic chemical raw material with low pollution and environmental friendliness, dimethyl carbonate (DMC) has active chemical properties, excellent physical properties, is non-toxic and easily degradable, and can be used as a solvent, gasoline additive, electrolyte for lithium-ion batteries, and carbonylation, methylation and carbonyl methoxylation reagents, and is widely used in the field of chemical industry. At present, there are various methods for producing DMC, among which the transesterification method has become a method with great industrial prospects because of its mild reaction conditions, high yield and co-production of ethylene glycol or propylene glycol.

[0003] At present, there are mainly two types of catalysts used for the preparation of DMC by the transesterification method, homogeneous catalysts and heterogeneous catalysts. Representative homogeneous catalysts include alkali metal hydroxides, alkali metal carbonates and alkali metal alcohols (US2011040117A1, WO2010063780A1), and there are problems such as difficult separation from products and difficult reuse. Heterogeneous catalysts mainly include alkali metals or alkali metal salts supported on carriers, metal oxide catalysts, zeolites or clay materials exchanged with alkali (earth) metals, and ion exchange resins. Among them, supported catalysts such as KF / Al 2 O 3 , NaOH / chitosan and Cs 2 CO 3 / SiO 2 -Al 2 O 3 etc. (CN101249452A; CN101121147A; WO0156971A1) have their activities decreased due to being easily affected by water and CO 2 in the air; metal oxide catalysts such as Al 2 O 3 , MgO, etc. (Appl.Catal.A, 2001, 21(9): 259-266; US2005080287A1; US6207850A1), and the activities and selectivities of zeolites or clay materials exchanged with alkali (earth) metals such as Cs-ZSM-5, Mg-smectite, etc. (WO2000073256A1; Catal.Lett., 2002, 83: 137-141) are usually relatively low; ion exchange resins, such as quaternary ammonium type or tertiary amine type resins (J.Mol.Catal.A, 1991, 67: 389-399; M.Cao etal.React.Kinet.Catal.Lett.88(2006)251-259) often have problems such as rapid decline in activity over a long time.

[0004] Therefore, for the transesterification reaction to prepare dimethyl carbonate, a heterogeneous catalyst with high activity and high stability needs to be developed. SUMMARY OF THE INVENTION

[0005] To solve the problems existing in the prior art, the present invention provides an ion exchange resin for transesterification, its preparation method and application. The ion exchange resin for transesterification of the present invention exhibits high activity and stability in the transesterification reaction for preparing dimethyl carbonate, and the preparation method provided by the present invention is simple and feasible, and can provide a reference for preparing other catalysts with higher performance.

[0006] One object of the present invention is to provide an ion exchange resin for transesterification, which has the general structural formula shown in formula (1):

[0007]

[0008] Among them, is the ion exchange resin matrix, and R is selected from at least one of hydrogen or C 1 ~C 10 saturated or unsaturated aliphatic hydrocarbon groups; X - is an anion or an anion group; the ion exchange resin for transesterification has spherical or quasi-spherical pores. is a functional group connected to the ion exchange resin matrix.

[0009] The pore size of the ion exchange resin is uniform and adjustable, and its unique pore structure is very conducive to mass diffusion.

[0010] In a preferred embodiment of the present invention,

[0011] R is selected from at least one of hydrogen, methyl, ethyl, n-propyl, isopropyl, propenyl, n-butyl, and n-pentyl; and / or,

[0012] The X - is selected from at least one of halide ions and organic acid root ions, preferably at least one of fluoride ions, chloride ions, bromide ions, iodide ions, acetate, formate, and hydrogen oxalate; and / or,

[0013] The most probable pore size of the ion exchange resin for transesterification is 20 - 500 nm, preferably 70 - 200 nm, more preferably 70 - 120 nm; and / or,

[0014] The particle size range of the ion exchange resin for transesterification is 350 - 600 μm. Preferably, the ion exchange resin for transesterification is spherical or quasi-spherical particles; and / or,

[0015] The ion exchange resin matrix is prepared by using modified nano-silica as a pore-forming agent; in the present invention, modified nano-silica is used as a pore-forming agent (template or porogen), and an ion exchange resin matrix with spherical or quasi-spherical pores, uniform and adjustable pore sizes is successfully synthesized; preferably, the ion exchange resin matrix is obtained by polymerizing components including styrene monomers, comonomers, and modified nano-silica and then treating with acid or base; more preferably,

[0016] The styrene monomer is selected from at least one of styrene and its derivatives, preferably at least one of styrene, α-methylstyrene, and 4-butylstyrene; and / or,

[0017] The comonomer is selected from at least one of divinylbenzenes, preferably at least one of diisopropenylbenzene and divinylbenzene; and / or,

[0018] The most probable particle size of the modified nano-silica is 20 - 500 nm, preferably 70 - 200 nm, more preferably 70 - 120 nm; and / or,

[0019] The modified nano-silica is obtained by modifying silica nanoparticles with a silane coupling agent containing double bonds; the size change of silica nanoparticles before and after modification is very small and can be ignored; and / or,

[0020] The acid is hydrofluoric acid; and / or,

[0021] The base is at least one of ammonia water, carbonates of alkali metals, and hydroxides of alkali metals, preferably at least one of ammonia water, sodium carbonate, sodium hydroxide, and potassium hydroxide; and / or,

[0022] The acid or base is used in the form of an aqueous solution, and its concentration is preferably 0.005 - 1.0 mol / L, more preferably 0.05 - 1.0 mol / L. The amount of the acid or base solution is at least such that the resin is completely dispersed in the acid or base solution. Preferably, the amount of the acid or base solution is 5 - 40 mL of the acid or base solution per 1 g of the resin before treatment. In the present invention, the acid or base treatment is to remove the silica nanoparticles in the resin, thereby generating macropores with spherical or quasi-spherical shapes, uniform and adjustable pore sizes in the resin.

[0023] In a preferred embodiment of the present invention,

[0024] The raw materials for preparing the ion exchange resin matrix further include carbon nanomaterials, and the carbon nanomaterials are preferably selected from at least one of graphene and carbon nanotubes; and / or,

[0025] The silane coupling agent containing a double bond is selected from at least one of allyl triethoxysilane, allyl trimethoxysilane, 3-butenyl triethoxysilane, vinyl triethoxysilane, vinyl trimethoxysilane, diethoxymethylvinylsilane, and methylvinyldimethoxysilane; and / or,

[0026] The most probable particle size of the silica nanoparticles before modification is 20 to 500 nm, preferably 70 to 200 nm, more preferably 70 to 120 nm; the change in the size of the silica nanoparticles before and after modification is very small and can be ignored; and / or,

[0027] The silica nanoparticles before modification can be obtained commercially or prepared by any method disclosed in the prior art in this field. In the present invention, the silica nanoparticles before modification are preferably obtained by hydrolysis and polycondensation of silicate compounds;

[0028] The preparation process of the silica nanoparticles before modification may specifically include the following steps: mixing an alcohol, water, and a catalyst uniformly, and then adding a silicate compound and reacting to obtain the silica nanoparticles before modification; wherein, the alcohol is preferably at least one of absolute ethanol and absolute methanol, and / or, the catalyst is preferably at least one of ammonia water and sodium carbonate, and / or, the volume ratio of the alcohol to water is (1 to 15):1, and / or, the mass ratio of the catalyst to water is (0.01 to 1):1, and / or, the volume ratio of the silicate to water is (0.1 to 0.8):1, and / or, the reaction temperature is preferably 10 to 60 °C, and the reaction time is preferably 0.1 to 5 h; preferably, the reaction is carried out under stirring, and the stirring rate is preferably 300 to 800 rpm.

[0029] The silicate compound is preferably selected from at least one of methyl silicate, ethyl silicate, propyl silicate, and butyl silicate; and / or,

[0030] The volume ratio of the silane coupling agent containing a double bond to the silicate compound is preferably 0.1 to 0.8, more preferably 0.2 to 0.4; and / or,

[0031] The temperature of the modification is 10 to 60 °C, preferably 20 to 40 °C; and / or, the time is 0.1 to 12 h, preferably 0.5 to 5 h.

[0032] In a preferred embodiment of the present invention,

[0033] First, synthesize the ion exchange resin matrix, and then successively carry out chloromethylation, imidazolization, and optionally transformation on the ion exchange resin matrix to obtain the ion exchange resin for transesterification.

[0034] A second object of the present invention is to provide a method for preparing the transesterification ion exchange resin of one of the objects of the present invention, which includes the steps of first synthesizing the ion exchange resin matrix, and then successively performing chloromethylation, imidazolization and optional transformation on the ion exchange resin matrix.

[0035] In a preferred embodiment of the present invention,

[0036] The method includes:

[0037] (1) Polymerizing components including styrene monomers, comonomers, optional carbon nanomaterials, and modified nano-silica in the presence of a dispersant and an initiator, and then dispersing them into an acid or alkali solution for treatment to obtain the ion exchange resin matrix;

[0038] (2) Successively performing chloromethylation, imidazolization and optional transformation on the ion exchange resin matrix obtained in step (1) to obtain the ion exchange resin for transesterification.

[0039] In a preferred embodiment of the present invention,

[0040] In step (1),

[0041] The dispersant is selected from at least one of polyvinyl alcohol, gelatin, starch, methylcellulose, bentonite, and calcium carbonate, preferably at least one of polyvinyl alcohol and gelatin; and / or,

[0042] The initiator is selected from at least one of peroxide initiators and azo initiators, preferably at least one of benzoyl peroxide, azobisisobutyronitrile, lauroyl peroxide, and cumene hydroperoxide, and more preferably at least one of benzoyl peroxide and azobisisobutyronitrile.

[0043] In a preferred embodiment of the present invention,

[0044] In step (1),

[0045] The mass ratio of the styrene monomers, comonomers, optional carbon nanomaterials, modified nano-silica, dispersant, and initiator is 1:(0.01 - 0.05):(0 - 0.1):(0.001 - 0.2):(0.04 - 0.15):(0.001 - 0.1), preferably 1:(0.01 - 0.03):(0 - 0.05):(0.001 - 0.1):(0.04 - 0.1):(0.001 - 0.02); and / or,

[0046] The temperature of the polymerization is 40 to 120 °C, and the time is 10 to 72 hours; preferably, the polymerization is carried out in a stepwise temperature increase manner. Preferably, pre-polymerization is carried out by stirring at 40 to 50 °C for 0.5 to 2 h, then the temperature is raised to 60 to 85 °C for reaction for 1 to 24 h, then the temperature is raised to 85 to 95 °C for reaction for 1 to 24 h, and finally the temperature is raised to 95 to 120 °C for reaction for 1 to 24 h; and / or,

[0047] The temperature of the treatment is 10 to 100 °C, preferably 60 to 100 °C; and / or, the time is 0.5 to 12 h, preferably 0.5 to 3 h; preferably, the treatment includes a step of stirring reaction, and the stirring rate is preferably 300 to 800 rpm.

[0048] In a preferred embodiment of the present invention,

[0049] In step (2),

[0050] The chloromethylation reagent used for the chloromethylation is selected from at least one of chloromethyl ether, chloroethyl ether, and chloromethyl ethyl ether, preferably at least one of chloromethyl ether and chloromethyl ethyl ether; and / or,

[0051] The imidazolization agent used for the imidazolization has a structure as shown in formula (2):

[0052]

[0053] Wherein, R 1 is selected from at least one of hydrogen or C 1 ~C 10 saturated or unsaturated aliphatic hydrocarbon groups, preferably at least one of hydrogen, methyl, ethyl, n-propyl, isopropyl, propenyl, n-butyl, and n-pentyl; and / or,

[0054] The transformation agent used for the transformation is selected from at least one of salt solutions containing at least one of halogen ions and organic acid root ions, preferably at least one of salt solutions containing at least one of fluoride ions, bromide ions, iodide ions, acetate, formate, and hydrogen oxalate.

[0055] In a preferred embodiment of the present invention,

[0056] In step (2),

[0057] The temperature of the chloromethylation is 30 to 60 °C, preferably 30 to 50 °C, and / or, the time of the chloromethylation is 8 to 30 h, preferably 8 to 15 h; and / or,

[0058] The conditions for the imidazolization include: reacting at the reflux temperature for 10 to 72 h, preferably reacting for 10 to 36 h; and / or,

[0059] The temperature of the transformation is 20 to 60 °C, preferably 20 to 35 °C, and / or the time of the transformation is 4 to 72 h, preferably 12 to 36 h.

[0060] The following specific technical solutions can be adopted in the present invention:

[0061] The synthesis method of the ion exchange resin for transesterification includes the following steps:

[0062] (1) First, synthesize silica nanoparticles, and then modify them with a silane coupling agent containing a double bond to obtain modified nano-silica.

[0063] (2) Polymerize the modified nano-silica prepared in step (1) with styrene monomers, comonomers, carbon nanomaterials, and a dispersant under the action of an initiator. The obtained spheres are then redispersed in an acid or base solution and treated for 0.5 to 12 h to obtain an ion exchange resin matrix.

[0064] (3) The ion exchange resin matrix prepared in step (2) is successively subjected to chloromethylation, imidazolization, and optionally transformation to obtain the ion exchange resin for transesterification.

[0065] In the above technical solution, preferably, in step (3), a chloromethylation reagent and a zinc chloride catalyst are added to the ion exchange resin matrix for a functionalization reaction. After the reaction is completed, it is washed with methanol and water and dried to obtain macroporous chlorinated spheres with spherical pores and uniform and adjustable pore sizes.

[0066] In the above technical solution, preferably, the weight of the chloromethylation reagent is 200% to 500% of the weight of the ion exchange resin matrix, and the weight of the zinc chloride catalyst is 20% to 70% of the weight of the ion exchange resin matrix.

[0067] In the above technical solution, preferably, in step (3), a swelling agent and an imidazolizing agent are added to the macroporous chlorinated spheres for a functionalization reaction; after the reaction is completed, it is washed with water and dried, and optionally a transformation agent is added for transformation, and then washed to neutral.

[0068] In the above technical solution, preferably, the swelling agent is selected from at least one of dichloromethane, 1,2-dichloroethane, chloroform, benzonitrile, toluene, tetrahydrofuran, and dimethylformamide. More preferably, it is one of dichloromethane or tetrahydrofuran;

[0069] In the above technical solution, preferably, the weight of the swelling agent is 200 to 700% of the weight of the macroporous chlorinated spheres.

[0070] In the above technical solution, preferably, the weight of the imidazolizing agent in step (3) is 70 to 250% of the weight of the macroporous chlorinated spheres.

[0071] In the above technical solution, preferably, the concentration of the transformation agent is preferably 0.01 - 2 mol / L.

[0072] In the present invention, the conditions for chloromethylation, amination, and transformation can all adopt conventional conditions in the art, and those skilled in the art can adjust them according to actual situations.

[0073] The third object of the present invention is to provide an application of an ion exchange resin of one of the objects of the present invention or an ion exchange resin obtained by the preparation method of the second object of the present invention in the transesterification reaction for preparing dimethyl carbonate.

[0074] In a preferred embodiment of the present invention,

[0075] The transesterification reaction includes a step of performing a transesterification reaction on ethylene carbonate and methanol in the presence of the ion exchange resin as a catalyst; preferably,

[0076] The molar ratio of methanol to ethylene carbonate is (2 - 20):1; and / or,

[0077] The weight ratio of the ion exchange resin to ethylene carbonate is (0.001 - 0.5):1; and / or,

[0078] The conditions of the transesterification reaction include: temperature 40 - 200 °C, and / or, time 0.1 - 6 h.

[0079] Advantages of the present invention:

[0080] (1) The pores of the ion exchange resin for transesterification of the present invention are spherical or quasi-spherical, with uniform and adjustable pore sizes, which is very conducive to mass diffusion, thereby enhancing its activity and stability as a catalyst. After the modified nano-silica is removed from the ion exchange resin for transesterification of the present invention by treatment with acid or base, its pores basically do not deform or only slightly deform relative to the shape of the modified nano-silica (pore-forming agent), and the pore size of the ion exchange resin for transesterification can be conveniently adjusted by controlling the size of the modified nano-silica; the method provided by the present invention is simple and feasible, and has good application prospects.

[0081] (2) The catalyst (ion exchange resin for transesterification) of the present invention shows high activity and stability in the transesterification reaction for preparing dimethyl carbonate. The conversion rate of ethylene carbonate can be as high as 88.1%, and the selectivities of dimethyl carbonate and ethylene glycol can both reach more than 99.6%. The performance remains basically unchanged after recycling 5 times or more. Description of the Drawings

[0082] Figure 1 It is the SEM photograph of the ion exchange resin prepared in Example 1.

[0083] Figure 2 It is the SEM photograph of the ion exchange resin prepared in Comparative Example 2. Specific Embodiments

[0084] The present invention will be specifically described below in conjunction with specific embodiments and the accompanying drawings. It is necessary to point out here that the following embodiments are only for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0085] If there is no special limitation on the raw materials used in the examples and comparative examples, they are all disclosed in the prior art. For example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0086] The morphology of the resins prepared in the examples and comparative examples was measured by a scanning electron microscope (SEM); the size of SiO 2 nanoparticles was measured by a nanoparticle size and zeta potential analyzer (Nano ZS90); the pore size of the resin pores was measured by a mercury porosimeter Pascal140 / 240.

[0087]

Example 1

[0088] 71.4 mL of absolute ethanol, 10 mL of deionized water and 1.57 mL of ammonia water (ammonia water concentration 14.84 mol / L) were uniformly mixed and placed in a water bath at 30 °C for magnetic stirring, and the stirring speed was 400 rpm. After the temperature was balanced, 3 mL of tetraethyl orthosilicate was quickly added to the above reaction solution, and the reaction was carried out for 1 h to obtain solid SiO 2 nanoparticles with the most probable particle size of 100 nm. 1 mL of allyltriethoxysilane was added and the reaction was continued for 1 h. After centrifugation, it was washed thoroughly with ethanol and dried to obtain modified nano-SiO 2 .

[0089] Take 54 g of styrene, 1.1 g of divinylbenzene, 0.5 g of benzoyl peroxide, 5.0 g of modified nano-SiO 2 and 1.0 g of multi-walled carbon nanotubes (Macklin, product number C805976) and ultrasonically disperse for 1 hour to obtain solution X. Dissolve 4.5 g of gelatin in 260 mL of deionized water and ultrasonically disperse it evenly. Add solution X to the gelatin aqueous solution, stir at 400 rpm at 40 °C for 2 h for prepolymerization, gradually raise the temperature to 80 °C, react for 5 h, then raise the temperature to 90 °C and react for 5 h, and finally raise the temperature to 98 °C and react for 6 h. After the reaction, pour out the upper liquid, wash it with hot water, filter, dry at 80 °C, and sieve to collect resin beads with a particle size in the range of 350 - 600 μm. Then disperse the obtained resin beads into 1000 mL of 0.6 mol / L Na2 CO 3 In an aqueous solution of, the reaction was stirred at 400 rpm at 80 °C for 1 hour, the product was collected, washed thoroughly with water, and dried to obtain an ion exchange resin matrix.

[0090] Take 40 g of the ion exchange resin matrix, add 150 mL of chloromethyl ethyl ether, let it stand at room temperature for 2 h, then stir and add 10 g of zinc chloride at 400 rpm, raise the temperature to 40 °C, react for 10 h. After the reaction is completed, cool to room temperature and pour out the reaction solution. Wash repeatedly with methanol and then wash with water and dry to obtain macroporous chlorinated beads. Take 40 g of chlorinated beads, 28 g of imidazole and 200 mL of benzonitrile, and reflux for 24 hours. After the reaction is completed, wash thoroughly with dichloromethane, acetone and water in sequence, and dry to obtain ion exchange resin A for transesterification. The particle size of the obtained ion exchange resin A for transesterification is 350 - 600 μm; the SEM photograph of the obtained ion exchange resin A for transesterification is as Figure 1 shown. It can be seen that the pores of the ion exchange resin A for transesterification are spherical or quasi-spherical, and their pore sizes are uniform. The most probable pore size measured is 100 nm. The functional groups connected to the ion exchange resin A for transesterification are:

[0091]

[0092]

Example 2

[0093] 71.4 mL of absolute ethanol, 10 mL of deionized water and 3 mL of ammonia water (ammonia water concentration 14.84 mol / L) were uniformly mixed and placed in a water bath at 30 °C for magnetic stirring, and the stirring speed was 400 rpm. After the temperature was balanced, 3 mL of tetraethyl orthosilicate was quickly added to the above reaction solution, and the reaction was carried out for 1 h to obtain solid SiO 2 nanoparticles with the most probable particle size of 80 nm. 1 mL of allyltriethoxysilane was added and the reaction was continued for 1 h. After centrifugation, it was washed thoroughly with ethanol and dried to obtain modified nano-SiO 2 .

[0094] Take 54 g of styrene, 1.1 g of divinylbenzene, 0.5 g of benzoyl peroxide, 3.0 g of modified nano-SiO 21.0 g of graphene (Macklin, catalog number G835835) was ultrasonically dispersed for 1 hour to obtain solution X. 4.5 g of gelatin was dissolved in 260 mL of deionized water and ultrasonically dispersed evenly. Solution X was added to the gelatin aqueous solution, and pre-polymerization was carried out by stirring at 400 rpm at 40 °C for 2 hours. The temperature was gradually raised to 80 °C and reacted for 5 hours, then raised to 90 °C and reacted for 5 hours, and finally raised to 98 °C and reacted for 6 hours. After the reaction was completed, the upper liquid was poured out, washed with hot water, filtered, dried at 80 °C, and sieved to collect resin beads with a particle size in the range of 350 - 600 μm. Then the obtained resin beads were dispersed into 1000 mL of an aqueous solution of 0.05 mol / L NaOH, and stirred and reacted at 400 rpm at 80 °C for 1 hour. The product was collected, washed thoroughly with water, and dried to obtain an ion exchange resin matrix.

[0095] 40 g of the ion exchange resin matrix was taken, 150 mL of chloromethyl ethyl ether was added, and after standing at room temperature for 2 h, 10 g of zinc chloride was added with stirring at 400 rpm. The temperature was raised to 40 °C and reacted for 10 h. After the reaction was completed, it was cooled to room temperature and the reaction solution was poured out. It was repeatedly washed with methanol and then washed with water and dried to obtain macroporous chlorinated beads. 40 g of chlorinated beads, 40 g of methylimidazole, and 200 mL of dichloromethane were taken and refluxed for 24 hours. After the reaction was completed, it was washed thoroughly with dichloromethane, acetone, and water in sequence, dried, and added to 500 mL of an aqueous solution of 0.1 mol / L NaBr and stirred at room temperature for 24 hours. It was washed thoroughly with deionized water and dried to obtain ion exchange resin B for transesterification. The particle size of the obtained ion exchange resin B for transesterification was 350 - 600 μm; the pore channels of the obtained ion exchange resin B for transesterification were spherical or quasi-spherical, and their pore sizes were uniform. The most probable pore size was measured to be 79 nm. The functional groups connected to the ion exchange resin B for transesterification were:

[0096]

Example 3

[0097] 71.4 mL of absolute ethanol, 10 mL of deionized water, and 3 mL of ammonia water (ammonia water concentration 14.84 mol / L) were uniformly mixed and placed in a water bath at 30 °C for magnetic stirring, and the stirring speed was 400 rpm. After the temperature was balanced, 4 mL of tetraethyl orthosilicate was quickly added to the above reaction solution, and reacted for 1 h to obtain solid SiO 2 nanoparticles with the most probable particle size of 90 nm. 1 mL of allyltriethoxysilane was added and continued to react for 1 h. After centrifugation, it was washed thoroughly with ethanol and dried to obtain modified nano-SiO 2 .

[0098] 54 g of styrene, 1.1 g of divinylbenzene, 0.5 g of benzoyl peroxide, 5.0 g of modified nano-SiO 21.0 g of single-walled carbon nanotubes (Macklin, catalog number C822928) was ultrasonically dispersed for 1 hour to obtain solution X. 4.5 g of gelatin was dissolved in 260 mL of deionized water and ultrasonically dispersed evenly. Solution X was added to the gelatin aqueous solution, and pre-polymerization was carried out by stirring at 400 rpm at 40 °C for 2 hours. The temperature was gradually raised to 80 °C and reacted for 5 hours, then raised to 90 °C and reacted for 5 hours, and finally raised to 98 °C and reacted for 6 hours. After the reaction was completed, the upper liquid was poured out, washed with hot water and filtered, dried at 80 °C, and sieved to collect resin beads with a particle size in the range of 350 - 600 μm. Then the obtained resin beads were dispersed into 1000 mL of an aqueous solution of 0.01 mol / L KOH, and stirred and reacted at 400 rpm at 80 °C for 1 hour. The product was collected, washed thoroughly with water, and dried to obtain an ion exchange resin matrix.

[0099] 40 g of the ion exchange resin matrix was taken, 150 mL of chloromethyl ethyl ether was added, and after standing at room temperature for 2 h, 10 g of zinc chloride was added with stirring at 400 rpm. The temperature was raised to 40 °C and reacted for 10 h. After the reaction was completed, the reaction solution was poured out after cooling to room temperature, washed repeatedly with methanol and then with water and dried to obtain macroporous chlorinated beads. 40 g of chlorinated beads, 50 g of ethylimidazole and 200 mL of tetrahydrofuran were taken and refluxed for 24 hours. After the reaction was completed, it was washed thoroughly with dichloromethane, acetone and water in sequence, dried and then added to 500 mL of an aqueous solution of 1 mol / L NaF at room temperature and stirred for 24 hours, washed thoroughly with deionized water and dried to obtain ion exchange resin C for transesterification. The particle size of the obtained ion exchange resin C for transesterification was 350 - 600 μm; the pore channels of the obtained ion exchange resin C for transesterification were spherical or quasi-spherical, and their pore sizes were uniform. The most probable pore size was measured to be 89 nm. The functional groups connected to the ion exchange resin C for transesterification were:

[0100]

Comparative Example 1

[0101] 71.4 mL of absolute ethanol, 10 mL of deionized water and 1.57 mL of ammonia water (ammonia water concentration 14.84 mol / L) were uniformly mixed and placed in a water bath at 30 °C for magnetic stirring, and the stirring speed was 400 rpm. After the temperature was balanced, 3 mL of tetraethyl orthosilicate was quickly added to the above reaction solution, and solid SiO 2 nanoparticles were obtained after reacting for 1 h, centrifuged, washed thoroughly with ethanol and dried.

[0102] 54 g of styrene, 1.1 g of divinylbenzene, 0.5 g of benzoyl peroxide, 5.0 g of solid SiO 2 nanoparticles and 1.0 g of multi-walled carbon nanotubes (Macklin, catalog number C805976) were ultrasonically dispersed for 1 hour to obtain solution X, and it was found that SiO 2Nanoparticles are difficult to disperse evenly. 4.5 g of gelatin was dissolved in 260 mL of deionized water and dispersed evenly by ultrasonic treatment. Solution X was added to the aqueous gelatin solution, and pre-polymerization was carried out by stirring at 400 rpm at 40 °C for 2 hours. The temperature was gradually raised to 80 °C and reacted for 5 hours, then raised to 90 °C and reacted for 5 hours, and finally raised to 98 °C and reacted for 6 hours. During the whole reaction process, most of the silica nanoparticles were distributed outside the suspension polymerization beads. After the reaction was completed, the upper liquid was poured out, washed with hot water, filtered, dried at 80 °C, and sieved to collect resin beads with a particle size in the range of 350-600 μm. Then the obtained resin beads were dispersed in 1000 mL of 0.6 mol / L Na 2 CO 3 aqueous solution, and stirred and reacted at 400 rpm at 80 °C for 1 hour, washed thoroughly with water and then dried.

[0103] 40 g of the above-treated resin beads were taken, 150 mL of chloromethyl ether was added, and after standing at room temperature for 2 h, 10 g of zinc chloride was added with stirring at 400 rpm, the temperature was raised to 40 °C, and the reaction was carried out for 10 h. After the reaction was completed, the reaction solution was poured out after cooling to room temperature, washed repeatedly with methanol and then washed with water and dried to obtain chlorinated beads. 40 g of chlorinated beads, 28 g of imidazole and 200 mL of benzonitrile were taken and refluxed for 24 hours. After the reaction was completed, they were washed thoroughly with dichloromethane, acetone and water in turn, and dried to obtain ion exchange resin D. The obtained ion exchange resin D was basically pore-free.

[0104]

Comparative Example 2

[0105] 54 g of styrene, 1.1 g of divinylbenzene, 0.5 g of benzoyl peroxide, 5.0 g of toluene and 1.0 g of multi-walled carbon nanotubes (Maclean, product number C805976) were ultrasonically dispersed for 1 hour to obtain solution X. 4.5 g of gelatin was dissolved in 260 mL of deionized water and dispersed evenly by ultrasonic treatment. Solution X was added to the aqueous gelatin solution, and pre-polymerization was carried out by stirring at 400 rpm at 40 °C for 2 hours. The temperature was gradually raised to 80 °C and reacted for 5 hours, then raised to 90 °C and reacted for 5 hours, and finally raised to 98 °C and reacted for 6 hours. After the reaction was completed, the upper liquid was poured out, washed with hot water, filtered, dried at 80 °C, and sieved to collect resin beads with a particle size in the range of 350-600 μm. Then the obtained resin beads were dispersed in 1000 mL of 0.6 mol / L Na 2 CO 3 aqueous solution, and stirred and reacted at 400 rpm at 80 °C for 1 hour, washed thoroughly with water and then dried.

[0106] Take 40 g of the above-mentioned treated resin beads, add 150 mL of chloromethyl ethyl ether, let it stand at room temperature for 2 h, then stir at 400 rpm and add 10 g of zinc chloride. Heat up to 40 °C and react for 10 h. After the reaction, cool it to room temperature and pour out the reaction solution. Wash it repeatedly with methanol and then wash it with water and dry it to obtain chlorinated beads. Take 40 g of chlorinated beads, 28 g of imidazole and 200 mL of benzonitrile, and reflux for 24 hours. After the reaction, wash it thoroughly with dichloromethane, acetone and water in sequence, and dry it to obtain ion exchange resin E. The SEM photograph of the obtained ion exchange resin E is as shown in Figure 2 shown, and it can be seen from Figure 2 that the pores generated by the traditional pore-forming agent have no fixed shape and are uneven in size.

[0107]

Test Example 1-12

[0108] Use the prepared ion exchange resin for transesterification as a catalyst in the transesterification reaction for preparing dimethyl carbonate (DMC): Place a certain amount of ethylene carbonate (EC), methanol and the catalyst in a 100 mL autoclave, heat up to the reaction temperature, and after reacting for a period of time, measure the EC conversion rate CEC, the DMC selectivity SDMC and the ethylene glycol selectivity SEG.

[0109] Table 1 Activity evaluation results of ion exchange resins A-C (i.e., catalysts A-C) in the transesterification reaction for preparing dimethyl carbonate

[0110]

[0111]

Comparative Example 3-4

[0112] Investigate the performance of ion exchange resins D and E (i.e., catalysts D, E) under the same conditions.

[0113] Table 2 Activity evaluation results of ion exchange resins D, E in the transesterification reaction for preparing dimethyl carbonate

[0114]

[0115]

[0116]

Test Example 13-16

[0117] Filter, wash and dry the catalyst A used in

Test Example 1

Test Example 1

[0118] Table 3 Recyclability of catalyst A

[0119] Test Example Catalyst Number of Cycles CEC / 100% SDMC / 100% SEG / 100% 13 A 2 62.6 99.8 99.8 14 A 3 62.5 99.7 99.9 15 A 4 62.5 99.7 99.8 16 A 5 62.6 99.8 99.9

[0120]

Comparative Examples 5 - 8

[0121] Under the same conditions, the recyclability of catalysts D and E was evaluated, and the results are shown in Table 4.

[0122] Table 4 Recyclability of Catalysts D and E

[0123] Comparative Example Catalyst Number of Cycles CEC / 100% SDMC / 100% SEG / 100% 5 D 2 55.1 99.6 99.6 6 D 3 53.9 99.5 99.5 7 E 2 57.5 99.7 99.6 8 E 3 56.2 99.6 99.6

[0124] It can be seen from Example 1, Comparative Example 1 and Tables 1 - 4 that: in Comparative Example 1, since the SiO 2 nanoparticles without being modified by a silane coupling agent containing double bonds were directly used as pore - forming agents, the resulting resin had basically no pores, so that its catalytic activity and stability were both inferior to those of the macroporous ion - exchange resin for transesterification of the present invention. It can be seen from Example 1, Comparative Example 2 and Tables 1 - 4 that: compared with the ion - exchange resin obtained by traditional pore - forming agents, the catalytic activity and stability of the ion - exchange resin for transesterification prepared by the present invention by using modified nano - SiO 2 as a pore - forming agent have significantly better effects.

[0125] The above - mentioned are only the preferred examples of the present invention. It should be pointed out that for those of ordinary skill in the art, under the technical inspiration provided by the present invention, as common general knowledge in the art, other equivalent variations and improvements can also be made, which should also be regarded as the protection scope of the present invention.

Claims

1. An ion exchange resin for transesterification, having the structural general formula shown in formula (1): Wherein, is an ion exchange resin matrix, and R is selected from hydrogen or C 1 ~C 10 at least one of saturated or unsaturated aliphatic hydrocarbon groups; X - is an anion or anionic group; the ion exchange resin for transesterification has spherical or quasi-spherical pores.

2. The ion exchange resin according to claim 1, Characterized in that: R is selected from at least one of hydrogen, methyl, ethyl, n-propyl, isopropyl, propenyl, n-butyl, and n-pentyl; and / or, Said X - selected from at least one of halide ions and organic acid root ions, preferably at least one of fluoride ions, chloride ions, bromide ions, iodide ions, acetate, formate, and hydrogen oxalate; and / or, The most probable pore diameter of the ion exchange resin for transesterification is 20-500 nm, preferably 70-200 nm; and / or, The particle size range of the ion exchange resin for transesterification is 350-600 μm; and / or, The ion exchange resin matrix is prepared with modified nano-silica as the pore-forming agent; preferably, The ion exchange resin matrix is obtained by polymerizing components including styrene monomers, comonomers, and modified nano-silica and then treating with acid or base; more preferably, The styrene monomers are selected from at least one of styrene and its derivatives, preferably at least one of styrene, α-methylstyrene, and 4-butylstyrene; and / or, The comonomers are selected from at least one of diene-based benzenes, preferably at least one of diisopropenylbenzene and divinylbenzene; and / or, The most probable particle size of the modified nano-silica is 20-500 nm, preferably 70-200 nm; and / or, The modified nano-silica is obtained by modifying silica nanoparticles with a silane coupling agent containing a double bond; and / or, The acid is hydrofluoric acid; and / or, The base is at least one of ammonia water, carbonates of alkali metals, and hydroxides of alkali metals, preferably at least one of ammonia water, sodium carbonate, sodium hydroxide, and potassium hydroxide; and / or, The acid or base is used in the form of an aqueous solution, and its concentration is preferably 0.005-1.0 mol / L, more preferably 0.05-1.0 mol / L.

3. The ion exchange resin according to claim 2, Characterized in that: The raw materials for preparing the ion exchange resin matrix further include carbon nanomaterials, and the carbon nanomaterials are preferably selected from at least one of graphene and carbon nanotubes; and / or, The silane coupling agent containing a double bond is selected from at least one of allyl triethoxysilane, allyl trimethoxysilane, 3-butene triethoxysilane, vinyl triethoxysilane, vinyl trimethoxysilane, diethoxymethylvinylsilane, and methylvinyldimethoxysilane; and / or, The most probable particle size of the silica nanoparticles before modification is 20-500 nm, preferably 70-200 nm; and / or, The silica nanoparticles before modification are obtained by hydrolysis and polycondensation of silicate compounds; the silicate compounds are preferably selected from at least one of methyl silicate, ethyl silicate, propyl silicate, and butyl silicate; and / or, the volume ratio of the silane coupling agent containing a double bond to the silicate compound is preferably 0.1-0.8, more preferably 0.2-0.4; and / or, The temperature of the modification is 10-60 °C, preferably 20-40 °C; and / or, the time is 0.1-12 h, preferably 0.5-5 h.

4. The ion exchange resin according to any one of claims 1-3, It is characterized in that: First, the ion exchange resin matrix is synthesized, and then the ion exchange resin matrix is successively subjected to chloromethylation, imidazolization, and optionally transformation to obtain the ion exchange resin for transesterification.

5. A method for preparing an ion exchange resin according to any one of claims 1-4, comprising the steps of first synthesizing the ion exchange resin matrix, and then successively subjecting the ion exchange resin matrix to chloromethylation, imidazolization, and optionally transformation.

6. The preparation method according to claim 5, It is characterized in that The method comprises: (1) Components including styrene monomers, comonomers, optionally carbon nanomaterials, and modified nano-silica are polymerized in the presence of a dispersant and an initiator, and then dispersed in an acid or base solution for treatment to obtain the ion exchange resin matrix; (2) The ion exchange resin matrix obtained in step (1) is successively subjected to chloromethylation, imidazolization, and optionally transformation to obtain the ion exchange resin for transesterification.

7. The preparation method according to claim 6, It is characterized in that: In step (1), The dispersant is selected from at least one of polyvinyl alcohol, gelatin, starch, methyl cellulose, bentonite, and calcium carbonate, preferably at least one of polyvinyl alcohol and gelatin; and / or, The initiator is selected from at least one of peroxide initiators and azo initiators, preferably at least one of benzoyl peroxide, azobisisobutyronitrile, lauroyl peroxide, and cumene hydroperoxide.

8. The preparation method according to claim 6, It is characterized in that: In step (1), The mass ratio of the styrene monomers, comonomers, optionally carbon nanomaterials, modified nano-silica, dispersant, and initiator is 1:(0.01-0.05):(0-0.1):(0.001-0.2):(0.04-0.15):(0.001-0.1), preferably 1:(0.01-0.03):(0-0.05):(0.001-0.1):(0.04-0.1):(0.001-0.02); and / or, The temperature of the polymerization is 40-120 °C, and the time is 10-72 hours; preferably, the polymerization is carried out in a stepwise temperature-raising manner, preferably with stirring at 40-50 °C for 0.5-2 h for pre-polymerization, then raising the temperature to 60-85 °C for reaction for 1-24 h, then raising the temperature to 85-95 °C for reaction for 1-24 h, and finally raising the temperature to 95-120 °C for reaction for 1-24 h; and / or, The temperature of the treatment is 10-100 °C, preferably 60-100 °C; and / or, the time is 0.5-12 h, preferably 0.5-3 h.

9. The preparation method according to claim 6, It is characterized in that: In step (2), The chloromethylation reagent used for chloromethylation is selected from at least one of chloromethyl ether, chloroethyl ether, and chloromethyl ethyl ether, preferably at least one of chloromethyl ether and chloromethyl ethyl ether; and / or, The structure of the imidazolizing agent used for imidazolization is shown in formula (2): wherein, R 1 is selected from at least one of hydrogen or C 1 ~C 10 saturated or unsaturated aliphatic hydrocarbon groups, preferably at least one of hydrogen, methyl, ethyl, n-propyl, isopropyl, propenyl, n-butyl, n-pentyl; and / or, The transformation agent used in the transformation is selected from at least one of salt solutions containing at least one of halogen ions and organic acid root ions, preferably from at least one of salt solutions containing at least one of fluoride ions, bromide ions, iodide ions, acetate, formate, and hydrogen oxalate.

10. The preparation method according to claim 6, characterized in that: in step (2), the temperature of the chloromethylation is 30 - 60 °C, preferably 30 - 50 °C, and / or the time of the chloromethylation is 8 - 30 h, preferably 8 - 15 h; and / or, the conditions of the imidazolization include: reacting at the reflux temperature for 10 - 72 h, preferably reacting for 10 - 36 h; and / or, the temperature of the transformation is 20 - 60 °C, preferably 20 - 35 °C, and / or the time of the transformation is 4 - 72 h, preferably 12 - 36 h.

11. Use of the ion exchange resin according to any one of claims 1 - 4 or the ion exchange resin prepared by the method according to any one of claims 5 - 10 in the transesterification reaction for preparing dimethyl carbonate.

12. The use according to claim 11, characterized in that: the transesterification reaction includes the step of carrying out a transesterification reaction of ethylene carbonate and methanol in the presence of the ion exchange resin as a catalyst; preferably, the molar ratio of methanol to ethylene carbonate is (2 - 20):1; and / or, the weight ratio of the ion exchange resin to ethylene carbonate is (0.001 - 0.5):1; and / or, the conditions of the transesterification reaction include: temperature 40 - 200 °C, and / or time 0.1 - 6 h.

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