A heterogeneous catalyst, its preparation method and application in preparing cyclohexane dicarboxylic acid diisononyl ester

Abstract

The present application relates to a kind of heterogeneous catalyst and its preparation method and application in the preparation of cyclohexane dicarboxylic acid diisononyl ester, belong to the technical field of organic synthesis.The heterogeneous catalyst is with polymer microspheres as carrier, titanate as modification group, the polymer microspheres are by macromolecular Raft reagent, polymerization monomer, chain transfer agent and solvent are mixed, then the dispersion polymerization reaction of the oxidation-reduction system composed of oxidizing agent and reducing agent is obtained.The catalyst has multiple active sites, high catalytic activity, easy with product ester separation and other advantages.The heterogeneous catalyst can be esterified under high temperature to obtain cyclohexane dicarboxylic acid diisononyl ester.Under normal pressure, hexahydrophthalic anhydride, isononyl alcohol and heterogeneous catalyst are added to the reaction kettle, to obtain cyclohexane dicarboxylic acid diisononyl ester.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, in particular to a heterogeneous catalyst, a preparation method thereof and application of the catalyst in preparation of diisononyl cyclohexane dicarboxylate. BACKGROUND

[0002] Diisononyl cyclohexane dicarboxylate is a new type of safe and environmentally friendly plasticizer, which has a similar structure to diisononyl phthalate, and thus has similar properties to diisononyl phthalate. In addition, diisononyl cyclohexane dicarboxylate has extremely low toxicological properties, and is widely used in medical devices, food packaging, children's products and toys, and other plastic products that come into contact with the human body. Diisononyl cyclohexane dicarboxylate is an ideal plastic additive.

[0003] At present, direct hydrogenation method, direct esterification method and ester exchange method are the main methods for synthesizing diisononyl cyclohexane dicarboxylate.

[0004] The preparation of diisononyl cyclohexane dicarboxylate usually involves esterification of phthalic anhydride with isononyl alcohol to produce diisononyl phthalate, and then hydrogenation. In the traditional esterification reaction, strong acid is often used as a catalyst. However, strong acid has high corrosion to the device equipment, which is not conducive to industrial production. In US6310235, it is disclosed that the esterification reaction occurs in two stages under the action of titanium or tin metal catalyst medium. The first stage is a mono-esterification reaction at a lower temperature (120-160℃), and then some metal catalyst is added and the temperature is increased to 250℃ for a di-esterification reaction. Direct hydrogenation method often uses noble metal catalysts (such as nickel, platinum, palladium, rhodium, ruthenium) to catalyze diisononyl phthalate for hydrogenation reaction to obtain diisononyl cyclohexane dicarboxylate. Although this process route is simple, it has high requirements for equipment and catalysts, and high cost. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provides a heterogeneous catalyst, a preparation method thereof and application of the catalyst in preparation of diisononyl cyclohexane dicarboxylate. The present application uses a heterogeneous catalyst to prepare diisononyl cyclohexane dicarboxylate through one-step esterification reaction at high temperature, which greatly shortens the mono-esterification reaction time and reduces energy consumption. In addition, the catalyst has multiple active sites, high catalytic activity, and is easy to separate from the product ester, which is beneficial to large-scale industrial production.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a heterogeneous catalyst, the catalyst comprising polymer microspheres and titanate loaded on the polymer microspheres; the polymer microspheres are obtained by polymerization reaction of a macromolecular Raft reagent, a polymerization monomer and a chain transfer agent in the presence of an oxidizing agent, a reducing agent and a solvent; the chemical structure of the macromolecular Raft reagent is shown in formula (1):

[0008]

[0009] wherein R1 is an alkane group of 12 carbon atoms, and the polymerization degree n is 50-400.

[0010] The heterogeneous catalyst of the present application uses polymer microspheres as a carrier and titanate as a modification group. The polymer microspheres have multiple active sites due to the addition of the macromolecular Raft reagent, and have the advantages of high catalytic activity, easy separation from product ester, recyclability and reusability.

[0011] Preferably, the structure of the chain transfer agent is shown in formula (2), wherein R1 is an alkane group of 12 carbon atoms.

[0012] Preferably, the polymerization monomer comprises at least one of vinyl acetate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, methyl acrylate, ethyl acrylate, isobornyl acrylate, butyl acrylate, lauryl acrylate, hydroxyethyl acrylate, glycidyl acrylate, isobutyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, butyl methacrylate, lauryl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, isodecyl methacrylate, isooctyl methacrylate, 2-hydroxypropyl methacrylate. More preferably, the polymerization monomer is glyceryl methacrylate.

[0013] Preferably, the oxidizing agent comprises at least one of hydrogen peroxide, sodium persulfate and hydroperoxide.

[0014] Preferably, the reducing agent comprises at least one of divalent iron salt, ascorbic acid, sodium ascorbate, sodium sulfite and sodium bisulfite.

[0015] Preferably, the titanate is at least one of tetrabutyl titanate, tetra-tert-butyl titanate, tetraisopropyl titanate, isopropyl tri(dioctyl pyrophosphato) titanate and tetraisobutyl titanate, and more preferably tetrabutyl titanate.

[0016] Preferably, the macromolecular Raft reagent accounts for 0.2-20wt% of the total mass of the polymerization monomer.

[0017] Preferably, the amount of the oxidizing agent and the reducing agent is 0.5-5wt% of the total mass of the polymerizable monomers.

[0018] Preferably, the molar ratio of the oxidizing agent and the reducing agent is (1-2):(1-2), more preferably 1:1.

[0019] Preferably, the polymerizable monomers are added in the form of a solution, and the mass concentration of the polymerizable monomers in the solution is 5-20wt%.

[0020] Preferably, the amount of the chain transfer agent is 0.02-2wt% of the total mass of the polymerizable monomers.

[0021] Preferably, the solvent is a mixture of water and ethanol, and the mass ratio of ethanol to water is 1:(0.5-2), more preferably 3:2.

[0022] In a second aspect, the present application provides a preparation method of a heterogeneous catalyst, comprising the following steps:

[0023] (1) mixing a macromolecular Raft reagent, polymerizable monomers, a chain transfer agent and a solvent, then adding an oxidizing agent and a reducing agent, and performing a dispersion polymerization reaction to obtain polymer microspheres;

[0024] (2) further adding a titanate into the polymer microspheres for modification, and obtaining the heterogeneous catalyst after modification.

[0025] Specifically, the preparation method of the heterogeneous catalyst comprises the following steps:

[0026] (1) mixing n-dodecyltrithio, trioctylmethylammonium chloride and a solvent, then adding a basic solution dropwise at 10-20℃, and then sequentially adding carbon disulfide solution, chloroform and a basic solution, performing a reaction, and removing the solvent to obtain S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate (DDMAT);

[0027] (2) mixing the DDMAT, glycerol methacrylate, azobisisobutyronitrile and 1,4 dioxane, performing a reaction under inert gas protection and at 40-100℃, precipitating using diethyl ether, and drying to obtain the macromolecular Raft reagent. The mass ratio of S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate, glycerol methacrylate and azobisisobutyronitrile is 1:(80-90):(0.01-0.02). In the structural formula (1), the value of n depends on the amount of glycerol methacrylate added.

[0028] (3) The macromolecular Raft reagent, polymerized monomer and DDMAT are dissolved in an ethanol / water medium, inert gas is introduced, and then a redox initiation system composed of an oxidizing agent and a reducing agent is added to perform dispersion polymerization, and a polymer microsphere with a surface rich in hydroxyl groups is obtained after the reaction. The inert gas includes at least one of nitrogen, argon and helium.

[0029] (4) The polymer microspheres and titanate are dispersed uniformly in anhydrous toluene under anhydrous conditions by using an immersion method and ultrasonic dispersion at 90 Hz, and then magnetic stirring is performed for 24-48 h to fully perform an ester exchange reaction, and then the polymer microspheres are washed three times with anhydrous toluene and vacuum dried to obtain polymer microspheres loaded with titanate.

[0030] In a third aspect, the present application provides a use of a heterogeneous catalyst in catalyzing an esterification reaction, such as preparing diisononyl cyclohexane dicarboxylate from isononyl alcohol and hexahydrophthalic anhydride, preparing diisooctyl maleate from maleic anhydride and isooctanol, and preparing methyl α-naphthylacetate from α-naphthylacetic acid and methanol.

[0031] Specifically, the heterogeneous catalyst is used in catalyzing diisononyl cyclohexane dicarboxylate from isononyl alcohol and hexahydrophthalic anhydride.

[0032] In a fourth aspect, the present application provides a method for preparing diisononyl cyclohexane dicarboxylate, including the following steps:

[0033] (1) Mixing hexahydrophthalic anhydride, isononyl alcohol and the heterogeneous catalyst, and performing esterification at 200-220 ℃ for 3-7 h to obtain the diisononyl cyclohexane dicarboxylate.

[0034] Preferably, the mass ratio of the hexahydrophthalic anhydride to the isononyl alcohol is 1:(2-4), and more preferably 1:(2.5-3).

[0035] Preferably, the heterogeneous catalyst accounts for 0.3-0.5% of the mass of the hexahydrophthalic anhydride.

[0036] Preferably, the method further includes a step of purifying the diisononyl cyclohexane dicarboxylate, and the purification includes one or more than two combinations of the following operations:

[0037] Preferably, the diisononyl cyclohexane dicarboxylate is subjected to flash evaporation to remove the azeotrope of water and isononyl alcohol, and the flash evaporation is performed under a negative pressure of -0.02-0.095 MPa.

[0038] Preferably, the aqueous solution of alkali metal hydroxide and the incompletely reacted phthalic anhydride are added to the diisononyl cyclohexane dicarboxylate in a mass concentration of 5-15%, and the aqueous solution of alkali metal hydroxide is used in excess, corresponding to 2-3 times the amount of acid in the mixture. Then the mixture is washed, separated and dried.

[0039] Preferably, 2-8% of activated carbon by mass of the diisononyl cyclohexane dicarboxylate is added to the diisononyl cyclohexane dicarboxylate, and stirred at 40-60°C for 0.5-1.5h. More preferably, the above steps are performed sequentially.

[0040] Compared with the prior art, the present application has the following advantages:

[0041] (1) The heterogeneous catalyst of the present application uses polymer microspheres as the carrier and titanate as the modifying group. The polymer microspheres are obtained by Raft dispersion polymerization reaction of a macromolecular Raft reagent, a polymerization monomer, DDMAT and a solvent, and then adding an oxidizing agent and a reducing agent to form an oxidation-reduction system. The surface of the polymer microspheres contains a large number of hydroxyl groups, which are ester-exchanged with the titanate to obtain the polymer microspheres loaded with the titanate. The polymer microspheres have multiple active sites, so that the catalyst has high catalytic activity, is easy to separate from the product ester, and has other advantages.

[0042] (2) In the preparation method of the diisononyl cyclohexane dicarboxylate of the present application, the reaction of phthalic anhydride, isononyl alcohol and the heterogeneous catalyst produces crude diisononyl cyclohexane dicarboxylate. In order to further purify the crude diisononyl cyclohexane dicarboxylate, the crude product is first subjected to flash evaporation, so that the water and part of the isononyl alcohol generated in the reaction process evaporate from the upper part of the reaction kettle and enter the alcohol recovery tower. After phase separation by condensation, the upper isononyl alcohol is refluxed to the alcohol recovery tower. In the initial stage, all of the isononyl alcohol returns to the isononyl alcohol recovery pipe. As the reaction tends to be stable, the amount of isononyl alcohol returned to the reaction kettle is adjusted by a flow meter. The lower liquid is water, which enters the water recovery tank. The crude ester after alcohol removal flows out from the bottom of the kettle, and is subjected to neutralization reaction with an alkali metal solution to remove unreacted anhydride in the esterification product. Then, the product is washed with water to remove the salt generated in the neutralization reaction and the excess alkali. After static separation, the final product is obtained by decolorization with activated carbon and filtration. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The figure is a schematic diagram of the structure of the polymer microspheres;

[0044] Figure 2 The figure is a schematic diagram of the structure of the heterogeneous catalyst. DETAILED DESCRIPTION

[0045] In order to better illustrate the purposes, technical solutions and advantages of the present application, the present application will be further described below in combination with specific examples. The test methods used in the examples and / or comparative examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are all commercially available unless otherwise specified.

[0046] Example 1

[0047] A heterogeneous catalyst, the catalyst comprising polymer microspheres and titanate supported on the polymer microspheres; the polymer microspheres are obtained by polymerization reaction of a macromolecular Raft reagent, a polymerizable monomer and a chain transfer agent in the presence of an oxidant, a reducing agent and a solvent; the titanate is tetrabutyl titanate; the polymerizable monomer is methyl methacrylate; the macromolecular Raft reagent is PGMA200-S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate, and the structural formula is as follows:

[0048] R1 is an alkyl group of 12 carbon atoms;

[0049] The chain transfer agent is S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate.

[0050] Specifically, the preparation method of S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate comprises the following steps:

[0051] n-dodecyl sulfide (80.21 g, 0.40 mol), 250 mL of acetone and tri-n-octylmethylammonium chloride are respectively added to a 500 mL three-necked round-bottom flask placed in a water bath, and mixed and dissolved by stirring at room temperature; the whole system is purged with nitrogen, the temperature of the water bath is reduced to 15°C using an ice bag, 50% sodium hydroxide aqueous solution is slowly added dropwise through a funnel, and the dropping is completed in 20 min; then carbon disulfide (15.20 g, 0.20 mol) is slowly added dropwise in acetone; the color of the solution changes to red during the dropping process; then 35.66 g of chloroform solvent is added, 80 g of sodium hydroxide aqueous solution is slowly added dropwise within half an hour, and the reaction is carried out at room temperature for 24 hours; after the solvent is removed, yellow solid powder is obtained; recrystallization is carried out twice in n-hexane to obtain 82.12 g of yellow crystal product, which is S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate, and the yield is about 80%. 1 H NMR (500 MHz, CDCl3): 0.99 (t, 3H), 1.37-1.47 (m, 20H), 1.75 (s, 6H), 3.42 (t, 2H), 13.05 (s, 1H).

[0052] The structural formula of S-n-dodecyl-S’-(2-methyl-2-propionyloxy)trithiocarbonate is as follows:

[0053]

[0054] R1 is an alkyl group of 12 carbon atoms.

[0055] The method of preparing the macro-RAFT agent comprises the following steps:

[0056] In a 100 mL single neck flask, S-n-dodecyl-S'-(2-methyl-2-propionyloxy)trithiocarbonate (0.36 g, 1 mmol), glyceryl methacrylate (32 g, 200 mmol), azobisisobutyronitrile (AIBN, 0.0062 g, 0.00375 mmol) and anhydrous 1,4 dioxane (30 mL) were added, and nitrogen was bubbled for 30 min, then the flask was placed in a preheated oil bath at 70 °C for 4 h. After the reaction, the product was precipitated with diethyl ether and dried in vacuum for 24 h to obtain the final product, macro-RAFT agent PGMA200-S-n-dodecyl-S'-(2-methyl-2-propionyloxy)trithiocarbonate, 1 H NMR (500 MHz, DMSO): 0.99 (t, 3H), 1.35-1.55 (m, 1020H), 1.78 (s, 6H), 3.48 (t, 2H), 3.62 (m, 2H), 3.9-4.25 (m, 1000H), 12.55 (s, 1H). The structural formula is as follows:

[0057] R1 is an alkyl group of 12 carbon atoms.

[0058] The method of preparing the polymer microspheres comprises the following steps:

[0059] A mixture solvent of 36 g of water and anhydrous ethanol (w / w = 60 / 40), 4 g of methyl methacrylate (MMA, 10% relative to the system) and 0.4 g of macro-RAFT agent (10% relative to the MMA monomer) were added to a 250 mL round bottom flask, and after stirring and dissolving, nitrogen was bubbled for 15 min, then 0.16 g of a mixture of hydrogen peroxide and ascorbic acid (4 wt% relative to the MMA monomer, and the molar ratio of hydrogen peroxide to ascorbic acid is 1:1) was added. After reaction at room temperature for 2 h, a stable emulsion product was obtained, which was filtered and dried in a vacuum drying oven at 80 °C for 2 h to obtain the microspheres with a surface rich in hydroxyl groups as shown in Figure 1 .

[0060] The method of preparing the heterogeneous catalyst of this embodiment comprises the following steps:

[0061] Into a single-necked flask, 10 g of polymer microspheres, 10 mL of tetrabutyl titanate and 300 mL of anhydrous toluene solvent were added, and after ultrasonic dispersion at 90 Hz until uniform, magnetic stirring was performed, and then filtration was performed, followed by washing with toluene, filtration, and repeating the washing 3 times, and then vacuum drying. After sufficient ester exchange reaction, 10% of tetrabutyl titanate-loaded polymer microsphere catalyst was obtained, which was a heterogeneous catalyst as shown in Formula (1). Figure 2

[0062] Example 2

[0063] The catalyst of Example 2 is different from that of Example 1 in that the titanate added to the polymer microspheres of Example 2 is tetra-t-butyl titanate.

[0064] Example 3

[0065] The catalyst of Example 3 is different from that of Example 1 in that the titanate added to the polymer microspheres of Example 3 is isopropyl tri(dioctyl pyrophosphato) titanate.

[0066] Example 4

[0067] The catalyst of Example 4 is different from that of Example 1 in that the titanate added to the polymer microspheres of Example 4 is tetraisobutyl titanate.

[0068] Comparative Example 1

[0069] The catalyst of Comparative Example 1 is different from that of Example 1 in that no titanate is added to the heterogeneous catalyst of Comparative Example 1.

[0070] Comparative Example 2

[0071] The catalyst of Comparative Example 2 is different from that of Example 1 in that the polymer microspheres loaded with tetrabutyl titanate are replaced by tetrabutyl titanate in Comparative Example 2.

[0072] Examples 1-4 and Comparative Examples 1-2

[0073] Examples 1-4 and Comparative Examples 1-2

[0074] Examples 1-4 and Comparative Examples 1-2

[0075] ​The hexahydrophthalic anhydride, isononyl alcohol and heterogeneous catalysts of each group were proportionally put into a reaction kettle. The ratio of the hexahydrophthalic anhydride to the isononyl alcohol was 1:3.5, and the input amount of the titanate-loaded polymer microsphere catalyst was 0.4% of the mass of the hexahydrophthalic anhydride. The reaction was stirred for 5 hours at a temperature of 220°C. While the reaction was carried out at a high temperature, the water generated in the reaction in the reaction kettle and part of the isononyl alcohol entered an alcohol recovery tower from the upper part of the reaction kettle through evaporation. After phase separation through condensation, the upper isononyl alcohol flowed back to the alcohol recovery tower, and in the initial stage, all returned to the isononyl alcohol recovery pipe. As the reaction tended to be stable, the amount of the isononyl alcohol returned to the reaction kettle was adjusted through a flow meter; the lower liquid was water, which entered a water recovery tank. The crude ester cyclohexane dimethyl acid diisononyl ester after alcohol removal flowed out from the bottom of the kettle, and was subjected to a neutralization reaction with an 8% mass fraction sodium hydroxide aqueous solution to remove the unreacted anhydride in the esterification product. Then, the water was washed to remove the salt and excess alkali generated in the neutralization reaction, and was statically separated. Then, 5% of the cyclohexane dimethyl acid diisononyl ester was added into activated carbon, and the refined cyclohexane dimethyl acid diisononyl ester was obtained through filtration. The cyclohexane dimethyl acid diisononyl ester obtained from each group was extracted and subjected to gas chromatography analysis, and the data results were recorded in Table 1.

[0076] Table 1 Performance of catalysts of each group in the preparation of cyclohexane dimethyl acid diisononyl ester

[0077]

[0078] As shown in Table 1, the titanate-loaded polymer microsphere catalysts in Examples 1-4 can be used for the esterification reaction to prepare cyclohexane dimethyl acid diisononyl ester, and the selectivity of the target acid product is higher, which can reach more than 99.5%. The catalyst used in Comparative Example 1 has no titanium acid ester added, which leads to a significant reduction in the conversion rate of the hexahydrophthalic anhydride, and the selectivity of the cyclohexane dimethyl acid diisononyl ester is reduced to 0, which indicates that the titanium acid ester is an important parameter for the selectivity of the catalyst in the esterification reaction. Moreover, the catalyst of the present application is easy to separate and recover from the product after the reaction, which simplifies the process operation process and also has industrial application value.

[0079] Application Example 5

[0080] Application Example 5 is to use the catalyst of Example 1 to catalyze the reaction of maleic anhydride and isooctanol as raw materials to prepare maleic acid diisononyl ester. The specific steps are as follows: the maleic anhydride, isooctanol and heterogeneous catalysts are proportionally put into a reaction kettle. The ratio of the maleic anhydride to the isooctanol is 1:3, and the input amount of the titanate-loaded polymer microsphere catalyst is 0.4% of the mass of the hexahydrophthalic anhydride. The reaction is stirred for 5 hours at a temperature of 180°C.

[0081] The conversion rate of the maleic anhydride is 99.6%, and the selectivity of the maleic acid diisononyl ester is 99.5%

[0082] Example 6

[0083] Example 6 is to use the catalyst of Example 1 to catalyze the raw material of α-naphthylacetic acid and methanol to prepare methyl α-naphthylacetate. The specific steps are as follows: α-naphthylacetic acid, methanol and heterogeneous catalyst are put into the reaction kettle in proportion. The proportion of α-naphthylacetic acid and methanol is 1:10, and the input amount of titanate-loaded polymer microsphere catalyst is 1% of the mass of hexahydrophthalic anhydride. The reaction is stirred for 5h at a temperature of 180℃.

[0084] Among them, the conversion rate of α-naphthylacetic acid is 92.7%, and the selectivity of methyl α-naphthylacetate is 99.2%.

[0085] In summary, the titanate-loaded polymer microsphere catalysts of Examples 1-4 can be used for esterification reaction, and the selectivity of the target acid product is high, which can reach more than 99%.

[0086] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A heterogeneous catalyst, characterized in that, The catalyst comprises polymer microspheres and titanate supported on the polymer microspheres; the polymer microspheres are obtained by polymerization of macromolecular Raft reagent, polymeric monomer and chain transfer agent in the presence of oxidant, reducing agent and solvent; the chemical structure of the macromolecular Raft reagent is shown in formula (1): Equation (1) Wherein, R1 is an alkane group with 12 carbon atoms, and the degree of polymerization n is 50-400; The chain transfer agent is S-dodecyl-S'-(2-methyl-2-propionic acid) trithiocarbonate; The chain transfer agent is used in an amount of 0.02~2 wt% of the total mass of the polymeric monomers. The macromolecular Raft reagent accounts for 0.2 to 20 wt% of the total mass of the polymeric monomers.

2. The heterogeneous catalyst according to claim 1, characterized in that, Such as at least one of (I) to (IV): (I) The polymerizing monomers include at least one of vinyl acetate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, methyl acrylate, ethyl acrylate, isobornyl acrylate, butyl acrylate, lauryl acrylate, hydroxyethyl acrylate, glycidyl acrylate, isobutyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, butyl methacrylate, lauryl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, isodecyl methacrylate, isooctyl methacrylate, and 2-hydroxypropyl methacrylate; (II) The oxidant includes at least one of hydrogen peroxide, sodium persulfate, and hydroperoxide; (III) The reducing agent includes at least one of ferrous salt, ascorbic acid, sodium anticortate, sodium sulfite, and sodium bisulfite; (IV) The titanate is at least one of tetrabutyl titanate, tetratert-butyl titanate, tetraisopropyl titanate, isopropyltris(dioctylpyrophosphoryloxy) titanate and tetraisobutyl titanate.

3. The heterogeneous catalyst as described in claim 1, characterized in that, Such as at least one of (I) to (IV): (I) The amount of the oxidant and reducing agent is 0.5~5 wt% of the total mass of the polymeric monomers; (II) The molar ratio of the oxidant to the reducing agent is (1~2):(1~2); (III) The polymeric monomer is added in the form of a solution, wherein the mass concentration of the polymeric monomer in the solution is 5-20 wt%; (IV) The solvent is a mixture of water and ethanol, with a mass ratio of ethanol to water of 1:(0.5~2).

4. The method for preparing the heterogeneous catalyst according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Mix macromolecular Raft reagent, polymeric monomer, chain transfer agent and solvent, then add oxidant and reducing agent to carry out dispersion polymerization reaction to obtain polymer microspheres; (2) Add titanate to the polymer microspheres for modification, and the heterogeneous catalyst is obtained after modification.

5. The method for preparing the heterogeneous catalyst as described in claim 4, characterized in that, The preparation method of the macromolecular Raft reagent includes the following steps: S-dodecyl-S'-(2-methyl-2-propionic acid) trithiocarbonate, glyceryl methacrylate, azobisisobutyronitrile, and 1,4-dioxane were mixed and subjected to esterification under inert gas protection at 40-100°C. After precipitation and drying, the macromolecular Raft reagent was obtained. The mass ratio of S-dodecyl-S'-(2-methyl-2-propionic acid) trithiocarbonate, glyceryl methacrylate, and azobisisobutyronitrile was 1:(80-90):(0.01-0.02).

6. The use of the heterogeneous catalyst according to any one of claims 1 to 3 in catalytic esterification reaction.

7. The application of the heterogeneous catalyst as described in claim 6, wherein the heterogeneous catalyst is used to catalyze the preparation of diisononyl cyclohexanedicarboxylate from isononol and hexahydrophthalic anhydride.

8. A method for preparing diisononyl cyclohexanedicarboxylate, characterized in that, Includes the following steps: Hexahydrophthalic anhydride, isononol, and the heterogeneous catalyst according to any one of claims 1 to 3 are mixed and reacted at 200 to 220°C to obtain the diisononyl cyclohexanedicarboxylate.

9. The method for preparing diisononyl cyclohexanedicarboxylate as described in claim 8, characterized in that, Such as at least one of (I) to (II): (I) The mass ratio of the hexahydrophthalic anhydride to the isononol is 1:(2~4). (II) The heterogeneous catalyst accounts for 0.3 to 0.5% of the mass of the hexahydrophthalic anhydride.

10. The method for preparing diisononyl cyclohexanedicarboxylate as described in claim 8 or 9, characterized in that, The process also includes a step of purifying the diisononyl cyclohexanedicarboxylate, wherein the purification process includes at least one of (I) to (III): (I) Flash evaporation of the diisononyl cyclohexanedicarboxylate; (II) Add an aqueous solution of alkali metal hydroxide to diisononyl cyclohexanedicarboxylate, wash, and then separate and dry. (III) Activated carbon is added to the diisononyl cyclohexanedicarboxylate for decolorization treatment.

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