Heterogeneous catalyst, preparation method thereof and application of heterogeneous catalyst in preparation of diisononyl cyclohexanedicarboxylate

Abstract

The invention relates to a heterogeneous catalyst, a preparation method thereof and application of the heterogeneous catalyst in preparation of diisononyl cyclohexanedicarboxylate, and belongs to the technical field of organic synthesis. The heterogeneous catalyst takes polymer microspheres as a carrier and titanate as a modification group, and the polymer microspheres are obtained by mixing a macromolecular Raft reagent, a polymeric monomer, a chain transfer agent and a solvent and then adding an oxidation-reduction system consisting of an oxidizing agent and a reducing agent for dispersion polymerization reaction. The catalyst has the advantages of multiple active sites, high catalytic activity, easiness in ester separation from a product and the like. The heterogeneous catalyst can be used for obtaining the cyclohexanedicarboxylic acid diisononyl ester at a high temperature through one-step esterification. The preparation method comprises the following steps: adding hexahydrophthalic anhydride, isononyl alcohol and a heterogeneous catalyst into a reaction kettle at normal pressure to obtain the cyclohexanedicarboxylic acid diisononyl ester.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a heterogeneous catalyst and a preparation method thereof, and application of the heterogeneous catalyst in the preparation of diisononyl cyclohexanedicarboxylate. Background Art

[0002] Diisononyl cyclohexanedicarboxylate is a new type of safe and environmentally friendly plasticizer. Its structure is similar to that of diisononyl phthalate, so it has similar properties to diisononyl phthalate and extremely low toxicity. It 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. It is an ideal plastic additive.

[0003] At present, direct hydrogenation, direct esterification and transesterification are the main methods for synthesizing diisononyl cyclohexanedicarboxylate.

[0004] The preparation of diisononyl cyclohexanedicarboxylate is usually carried out by esterification of phthalic anhydride and isononyl alcohol to generate diisononyl phthalate, and then obtain it by hydrogenation. In the traditional esterification reaction, strong acid is often used as a catalyst, which is not conducive to industrial production because of its high corrosiveness to the equipment. U.S. Patent No. 6310235 discloses that the esterification reaction under a metal catalyst such as titanium or tin is divided into two stages. The first stage is a monoesterification reaction at a relatively low temperature (120-160° C.), and then some metal catalysts are added and the temperature is increased to 250° C. to carry out a double esterification reaction. The direct hydrogenation method often uses a noble metal catalyst (such as nickel, platinum, palladium, rhodium, ruthenium) to catalyze diisononyl phthalate under high temperature and high pressure to hydrogenate to obtain diisononyl cyclohexanedicarboxylate. Although the process route is simple, it has high requirements for equipment and catalysts and is costly. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a heterogeneous catalyst and a preparation method thereof and an application thereof in the preparation of diisononyl cyclohexanedicarboxylate. The present invention adopts a heterogeneous catalyst to prepare diisononyl cyclohexanedicarboxylate by a one-step esterification reaction at a high temperature, which greatly shortens the monoesterification reaction time and has a low energy consumption rate. In addition, the catalyst has multiple active sites, high catalytic activity, and is easy to separate from the product ester, which is conducive to industrial large-scale production.

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

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

[0008]

[0009] Among them, R 1 It is an alkane group with 12 carbon atoms and a degree of polymerization n of 50-400.

[0010] The heterogeneous catalyst of the present invention uses polymer microspheres as carriers and titanate as a modifying group. The polymer microspheres have multiple active sites due to the addition of a macromolecular Raft agent, and have the advantages of high catalytic activity, easy separation from the product ester, and recyclability and reuse.

[0011] Preferably, the chain transfer agent has a structural formula as shown in formula (2), Among them, R 1 It is an alkane group of 12 carbon atoms.

[0012] Preferably, the polymerizable monomer includes 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. More preferably, the polymerizable monomer is glyceryl methacrylate.

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

[0014] Preferably, the reducing agent comprises at least one of ferrous 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 pyrophosphate) titanate and tetraisobutyl titanate, and more preferably tetrabutyl titanate.

[0016] Preferably, the macromolecular Raft agent accounts for 0.2-20 wt % of the total mass of the polymerizable monomers.

[0017] Preferably, the amount of the oxidant and the reductant used is 0.5 to 5 wt % of the total mass of the polymerizable monomers.

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

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

[0020] Preferably, the amount of the chain transfer agent is 0.02-2 wt % 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 invention provides a method for preparing a heterogeneous catalyst, comprising the following steps:

[0023] (1) mixing a macromolecular Raft agent, a polymerization monomer, a chain transfer agent and a solvent, and then adding an oxidant and a reducing agent to carry out a dispersion polymerization reaction to obtain polymer microspheres;

[0024] (2) Titanate is then added to the polymer microspheres for modification, and the heterogeneous catalyst is obtained after modification.

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

[0026] (1) mixing n-dodecyl sulfide, trioctyl methyl ammonium chloride and a solvent, adding an alkaline solution dropwise at 10-20° C., then sequentially adding a carbon disulfide solution, chloroform and an alkaline solution, reacting, and removing the solvent to obtain S-n-dodecyl-S'-(2-methyl-2-propionic acid) trithiocarbonate (DDMAT);

[0027] (2) The DDMAT, methacrylate glyceryl, azobisisobutyronitrile and 1,4-dioxane are mixed, reacted at 40-100°C under the protection of an inert gas, precipitated with ether, and dried to obtain the macromolecular Raft reagent. The mass ratio of S-n-dodecyl-S'-(2-methyl-2-propionyl) trithiocarbonate, methacrylate glyceryl and azobisisobutyronitrile is 1: (80-90): (0.01-0.02). The value of n of the degree of polymerization in the structural formula (1) depends on the amount of methacrylate glyceryl added.

[0028] (3) dissolving the macromolecular Raft reagent, polymerizable monomer and DDMAT in an ethanol / water medium, introducing an inert gas, and then adding a redox initiation system consisting of an oxidant and a reductant to carry out a dispersion polymerization reaction, and obtaining polymer microspheres having a rich surface hydroxyl group after the reaction. The inert gas includes at least one of nitrogen, argon and helium.

[0029] (4) The polymer microspheres and titanate were dispersed uniformly by ultrasonic dispersion at 90 Hz in anhydrous toluene by an immersion method under anhydrous conditions, and then subjected to magnetic stirring for 24 to 48 hours. After sufficient transesterification reaction, the microspheres were washed three times with anhydrous toluene and vacuum dried to obtain titanate-loaded polymer microspheres.

[0030] In a third aspect, the present invention provides an application of a heterogeneous catalyst in a catalytic esterification reaction, such as preparing diisononyl cyclohexanedicarboxylate using isononyl alcohol and hexahydrophthalic anhydride as raw materials, preparing diisooctyl maleate using maleic anhydride and isooctyl alcohol as raw materials, preparing methyl α-naphthylacetate using α-naphthylacetic acid and methanol as raw materials, etc.

[0031] Specifically, the heterogeneous catalyst is used in catalyzing isononyl alcohol and hexahydrophthalic anhydride to prepare diisononyl cyclohexanedicarboxylate.

[0032] In a fourth aspect, the present invention provides a method for preparing diisononyl cyclohexanedicarboxylate, comprising the following steps:

[0033] (1) Hexahydrophthalic anhydride, isononanol and the heterogeneous catalyst are mixed, and an esterification reaction is carried out at 200-220° C. for 3-7 hours to obtain the cyclohexanedicarboxylic acid diisononyl ester.

[0034] Preferably, the mass ratio of the hexahydrophthalic anhydride to the isononanol is 1:(2-4), 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 comprises a step of purifying the diisononyl cyclohexanedicarboxylate, wherein the purification treatment comprises one or a combination of two or more of the following operations:

[0037] Preferably, the diisononyl cyclohexanedicarboxylate is flash distilled to remove the azeotrope of water and isononanol; wherein the flash distillation is carried out under a negative pressure of -0.02 to 0.095 MPa.

[0038] Preferably, an aqueous solution of alkali metal hydroxide with a mass concentration of 5-15% and unreacted hexahydrophthalic anhydride are added to diisononyl cyclohexanedicarboxylate, that is, the aqueous solution of alkali metal hydroxide is used in excess, equivalent to 2-3 times the acid amount of the mixture. The mixture is then washed, separated and dried.

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

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The heterogeneous catalyst of the present invention uses polymer microspheres as carriers and titanate as a modifying group. The polymer microspheres are obtained by mixing a macromolecular Raft reagent, a polymer monomer, DDMAT and a solvent, and then adding a redox system consisting of an oxidant and a reductant to carry out Raft dispersion polymerization. Because the surface of the polymer microspheres contains a large number of hydroxyl groups, the polymer microspheres are subjected to an ester exchange reaction with titanate to obtain titanate-loaded polymer microspheres, so that the polymer microspheres have multiple active sites, thereby making the catalyst have the advantages of high catalytic activity and easy separation from the product ester.

[0042] (2) In the preparation method of diisononyl cyclohexanedicarboxylate of the present invention, the crude diisononyl cyclohexanedicarboxylate is obtained after the reaction of hexahydrophthalic anhydride, isononyl alcohol and heterogeneous catalyst. In order to further purify the crude diisononyl cyclohexanedicarboxylate, the crude product is first flashed, so that the water and part of isononyl alcohol generated in the reaction process enter the alcohol recovery tower from the upper part of the reactor by evaporation, and then the upper isononyl alcohol is refluxed to the alcohol recovery tower after condensation and phase separation. In the initial stage, all isononyl alcohol returns to the isononyl alcohol recovery pipe. As the reaction tends to be stable, the amount of isononyl alcohol returned to the reactor is adjusted by a flow meter; the lower liquid is water and enters the recovery water tank. The crude ester after dealcoholization flows out from the bottom of the reactor, and is neutralized with an alkali metal solution to remove the unreacted anhydride in the esterification product, and then washed with water to remove the salt and excess alkali generated by the neutralization reaction, static separation, and finally decolorized by activated carbon adsorption, and filtered to obtain the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the characterization structure of polymer microspheres;

[0044] Figure 2 Schematic diagram of the characterization structure of heterogeneous catalysts. DETAILED DESCRIPTION

[0045] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific examples. The test methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0046] Example 1

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

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

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

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

[0051] n-Dodecyl sulfide (80.21 g, 0.40 mol), 250 mL of acetone and trioctyl methyl ammonium chloride were added to a 500 mL three-necked round-bottom flask placed in a water bath, and stirred at room temperature to mix and dissolve; nitrogen was introduced into the whole system, the temperature of the water bath was lowered to 15° C. using an ice bag, 50% sodium hydroxide aqueous solution was slowly added dropwise using a funnel, and the addition was completed within 20 min, and then an acetone solution containing carbon disulfide (15.20 g, 0.20 mol) was slowly added dropwise, and the color of the solution turned red during the addition; then 35.66 g of chloroform solvent was added, and 80 g of sodium hydroxide aqueous solution was slowly added dropwise within half an hour, and the reaction was carried out at room temperature for 24 hours. After the solvent was removed by vortexing, a yellow solid powder was obtained; and recrystallization was performed twice in n-hexane to obtain 82.12 g of a yellow crystalline product, namely S-n-dodecyl-S'-(2-methyl-2-propionic acid group) trithiocarbonate, with a yield of about 80%. 1 H NMR (500MHz, 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-propionic acid) trithiocarbonate is as follows:

[0053]

[0054] R1 is an alkane group having 12 carbon atoms.

[0055] The preparation method of the macromolecular RAFT agent comprises the following steps:

[0056] S-n-dodecyl-S'-(2-methyl-2-propionic acid) trithiocarbonate (0.36 g, 1 mmol), methacrylate glycerol (32 g, 200 mmol), azobisisobutyronitrile (AIBN, 0.0062 g, 0.00375 mmol) and anhydrous 1,4-dioxane (30 mL) were added to a 100 mL single-necked flask, and nitrogen was introduced for 30 min. Then, the flask was placed in a preheated oil bath at 70 ° C. and reacted for 4 hours. After the reaction, the product was precipitated with ether and vacuum dried for 24 hours to obtain the final product, macromolecular RAFT agent PGMA200-S-n-dodecyl-S'-(2-methyl-2-propionic acid) trithiocarbonate. 1 H NMR (500MHz, 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 alkane group having 12 carbon atoms.

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

[0059] 36 g of a mixed solvent 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 a macromolecular RAFT agent (10% relative to the MMA monomer) were added to a 250 mL round-bottom flask, stirred and dissolved, and nitrogen was introduced for 15 min, and then 0.16 g of a mixture of hydrogen peroxide and ascorbic acid (4 wt% relative to the MMA monomer, wherein the molar ratio of hydrogen peroxide to ascorbic acid was 1:1) was added, and a stable emulsion product was obtained after reacting at room temperature for 2 hours. After filtering, it was placed in a vacuum drying oven at 80° C. and dried for 2 h to obtain the following product: Figure 1 Microspheres with hydroxyl-rich surfaces are shown.

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

[0061] 10g polymer microspheres, 10ml tetrabutyl titanate and 300ml anhydrous toluene solvent were added to a single-necked flask, ultrasonically dispersed until uniform, magnetically stirred, filtered, washed with toluene, filtered, washed three times, and vacuum dried. After sufficient transesterification reaction, a 10% tetrabutyl titanate-loaded polymer microsphere catalyst was obtained, which is Figure 2 The heterogeneous catalyst is shown.

[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-tert-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 pyrophosphate) 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 titanate is not 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 with tetrabutyl titanate in Comparative Example 2.

[0072] Application Examples 1 to 4 and Application Comparative Examples 1 to 2

[0073] The use of the catalysts of Examples 1 to 4 to prepare diisononyl cyclohexanedicarboxylate is recorded as Application Examples 1 to 4, respectively; the use of the catalysts of Comparative Examples 1 to 2 to prepare diisononyl cyclohexanedicarboxylate is recorded as Comparative Application Examples 1 to 2, respectively.

[0074] The specific steps for preparing diisononyl cyclohexanedicarboxylate in Application Examples 1 to 4 and Comparative Examples 1 to 2 are as follows:

[0075] Hexahydrophthalic anhydride, isononanol and heterogeneous catalysts of each group were put into the reactor in proportion. Among them, the ratio of hexahydrophthalic anhydride to isononanol was 1:3.5, and the amount of polymer microsphere catalyst loaded with titanate was 0.4% of the mass of hexahydrophthalic anhydride. The reaction was stirred at a temperature of 220°C for 5 hours. While the reaction was carried out at high temperature, the water and part of the isononanol generated in the reactor were evaporated from the upper part of the reactor into the alcohol recovery tower. After condensation and phase separation, the upper isononanol refluxed to the alcohol recovery tower, and all returned to the isononanol recovery pipe at the beginning. As the reaction became stable, the amount of isononanol returned to the reactor was adjusted by the flow meter; the lower liquid was water, which entered the recovery water tank. The crude ester diisononyl cyclohexanedicarboxylate after dealcoholization flows out from the bottom of the kettle, and is neutralized with an aqueous sodium hydroxide solution with a mass fraction of 8% to remove the unreacted anhydride in the esterification product, and then washed with water to remove the salt and excess alkali generated by the neutralization reaction, and then statically separated, and then activated carbon with a mass fraction of 5% of diisononyl cyclohexanedicarboxylate is added, and the refined diisononyl cyclohexanedicarboxylate is obtained by filtration. The diisononyl cyclohexanedicarboxylate obtained in each group is extracted for gas chromatography analysis, and the data results are recorded in Table 1.

[0076] Table 1 Performance of each group of catalysts in preparing diisononyl cyclohexanedicarboxylate

[0077]

[0078] As shown in Table 1, the polymer microsphere catalysts loaded with titanate in Examples 1 to 4 can be used for esterification to prepare diisononyl cyclohexanedicarboxylate, and the selectivity of the target acid product is higher, reaching more than 99.5%. However, the catalyst used in Comparative Example 1, due to the absence of titanate, leads to a significant reduction in the conversion rate of hexahydrophthalic anhydride, and the selectivity of diisononyl cyclohexanedicarboxylate is reduced to 0, indicating that titanate is an important parameter for the selectivity of the catalyst esterification reaction. Moreover, the catalyst of the present invention is easy to separate and recover from the product after the reaction is completed, which simplifies the process operation flow 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 isooctyl alcohol as raw materials to prepare diisooctyl maleate, and the specific steps are: maleic anhydride, isooctyl alcohol and heterogeneous catalyst are added to the reactor in proportion. Among them, the ratio of maleic anhydride to isooctyl alcohol is 1:3, and the amount of the titanate-supported polymer microsphere catalyst added is 0.4% of the mass of hexahydrophthalic anhydride. The reaction is stirred at a temperature of 180°C for 5 hours.

[0081] Among them, the conversion rate of maleic anhydride is 99.6%, and the selectivity of diisooctyl maleate is 99.5%

[0082] Application Example 6

[0083] Application Example 6 uses the catalyst of Example 1 to catalyze α-naphthylacetic acid and methanol raw materials to prepare α-naphthylacetic acid methyl ester, and the specific steps are: α-naphthylacetic acid, methanol and heterogeneous catalyst are added to the reactor in proportion. Among them, the ratio of α-naphthylacetic acid to methanol is 1:10, and the amount of titanate-supported polymer microsphere catalyst added is 1% of the mass of hexahydrophthalic anhydride. The reaction is stirred at a temperature of 180°C for 5 hours.

[0084] The conversion rate of α-naphthylacetic acid was 92.7%, and the selectivity of α-naphthylacetic acid methyl ester was 99.2%.

[0085] In summary, the polymer microsphere catalysts loaded with titanate in Examples 1 to 4 can be used for esterification reactions, and the selectivity of the target acid product is high, reaching more than 99%.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A heterogeneous catalyst, characterized in that The catalyst comprises polymer microspheres and titanate loaded on the polymer microspheres; the polymer microspheres are obtained by polymerization reaction of a macromolecular Raft agent, a polymerization monomer and a chain transfer agent in the presence of an oxidant, a reducing agent and a solvent; the chemical structure of the macromolecular Raft agent is shown in formula (1): Wherein, R1 is an alkane group with 12 carbon atoms, and the degree of polymerization n is 50-400.

2. The heterogeneous catalyst according to claim 1, characterized in that At least one of (I) to (IV): (I) the chain transfer agent is S-n-dodecyl-S'-(2-methyl-2-propionyl) trithiocarbonate; (II) the polymerizable 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; (III) the oxidant comprises at least one of hydrogen peroxide, sodium persulfate, and hydroperoxide; (IV) the reducing agent comprises at least one of a divalent iron salt, ascorbic acid, sodium ascorbate, sodium sulfite, and sodium bisulfite; (V) The titanate is at least one of tetrabutyl titanate, tetra-tert-butyl titanate, tetraisopropyl titanate, isopropyl tri(dioctyl pyrophosphate) titanate and tetraisobutyl titanate.

3. The heterogeneous catalyst according to claim 1, characterized in that At least one of (I) to (VI): (I) the macromolecular Raft agent accounts for 0.2 to 20 wt% of the total mass of the polymerized monomers; (II) the amount of the oxidizing agent and the reducing agent is 0.5 to 5 wt% of the total mass of the polymerizable monomers; (III) the molar ratio of the oxidizing agent to the reducing agent is (1-2): (1-2); (IV) the polymerizable monomer is added in the form of a solution, wherein the mass concentration of the polymerizable monomer in the solution is 5 to 20 wt %; (V) the amount of the chain transfer agent is 0.02 to 2 wt% of the total mass of the polymerizable monomers; (VI) The solvent is a mixture of water and ethanol, and the mass ratio of ethanol to water is 1:(0.5-2).

4. The method for preparing a heterogeneous catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) mixing a macromolecular Raft agent, a polymerization monomer, a chain transfer agent and a solvent, and then adding an oxidant and a reducing agent to carry out a dispersion polymerization reaction to obtain polymer microspheres; (2) Titanate is then added to the polymer microspheres for modification, and the heterogeneous catalyst is obtained after modification.

5. The method for preparing a heterogeneous catalyst according to claim 4, characterized in that: The preparation method of the macromolecular Raft reagent comprises the following steps: S-n-dodecyl-S'-(2-methyl-2-propionyl) trithiocarbonate, methacrylate glyceryl, azobisisobutyronitrile and 1,4-dioxane are mixed, and an esterification reaction is carried out at 40-100° C. under the protection of an inert gas, and then the mixture is precipitated and dried to obtain the macromolecular Raft reagent; wherein the mass ratio of S-n-dodecyl-S'-(2-methyl-2-propionyl) trithiocarbonate, methacrylate glyceryl and azobisisobutyronitrile is 1:(80-90):(0.01-0.02).

6. Use of the heterogeneous catalyst according to any one of claims 1 to 3 in catalytic esterification reactions.

7. Use of the heterogeneous catalyst as claimed in claim 6, wherein the heterogeneous catalyst is used to catalyze the preparation of diisononyl cyclohexanedicarboxylate from isononyl alcohol and hexahydrophthalic anhydride.

8. A method for preparing diisononyl cyclohexanedicarboxylate, characterized in that: The following steps are involved: (1) Hexahydrophthalic anhydride, isononanol 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 according to claim 8, wherein At least one of (I) to (III): (I) the mass ratio of the hexahydrophthalic anhydride to the isononanol is 1:(2-4); (II) The heterogeneous catalyst accounts for 0.3-0.5% of the mass of the hexahydrophthalic anhydride.

10. The method for preparing diisononyl cyclohexanedicarboxylate according to claim 8 or 9, characterized in that: The method further comprises the step of purifying the diisononyl cyclohexanedicarboxylate, wherein the purification treatment comprises at least one of (I) to (III): (1) flash distilling the diisononyl cyclohexanedicarboxylate; (II) adding an aqueous solution of alkali metal hydroxide to diisononyl cyclohexanedicarboxylate, washing, separating and drying; (III) adding activated carbon to the diisononyl cyclohexanedicarboxylate for decolorization.

Images