阅读说明：本技术 一种苯乙烯基二苯胺抗氧剂及其制备方法 (Styryl diphenylamine antioxidant and preparation method thereof ) 是由 李俊乐 于 2021-02-19 设计创作，主要内容包括：本发明一种用于生产苯乙烯基二苯胺抗氧剂的制备方法,以二苯胺与α-甲基苯乙烯为原料,以SO-4～(2-)改性的钛柱撑白土和钛基离子液体相结合的复合物作为催化剂,进行烷基化反应、重结晶制得抗氧化剂；该催化剂是通过钛柱撑白土的制备、SO-4～(2-)改性钛柱撑白土的制备、离子液体前驱体MIMPS的制备及Ti基离子液体与SO-4～(2-)改性钛柱撑白土的原位复合得到的,催化剂中SO-4～(2-)改性的钛柱撑白土的质量分数为50～70wt%,所述钛基离子液体为Ti-(0.25)[MIMPS]-2PMo-(12)O-(40)、Ti-(0.50)[MIMPS]PMo-(12)O-(40)、Ti-(0.25)[MIMPS]HPMo-(12)O-(40)中的一种。本发明既能解决传统AlCl-3基催化剂在使用过程中由于酸性容易流失造成失活的不足,又具有对反应装置无腐蚀性和催化效率高的优势,并且可以有效避免传统AlCl-3基催化剂在分离过程中产生大量污水的不足。(The invention relates to a preparation method for producing styryl diphenylamine antioxidant, which takes diphenylamine and alpha-methylstyrene as raw materials and SO 4 2‑ Taking a compound of the modified titanium pillared argil and the titanium-based ionic liquid as a catalyst, and carrying out alkylation reaction and recrystallization to obtain an antioxidant; the catalyst is prepared by preparing titanium pillared argil and SO 4 2‑ Preparation of modified titanium pillared clay, preparation of ionic liquid precursor MIMPS and Ti-radical ionic liquids with SO 4 2‑ Obtained by in-situ compounding of modified titanium pillared clay, and SO in catalyst 4 2‑ The mass fraction of the modified titanium pillared argil is 50-70 wt%, and the titanium-based ionic liquid is Ti 0.25 [MIMPS] 2 PMo 12 O 40 、Ti 0.50 [MIMPS]PMo 12 O 40 、Ti 0.25 [MIMPS]HPMo 12 O 40 One kind of (1). The invention can solve the problem of the traditional AlCl 3 The base catalyst has the defects of easy loss of acid to cause inactivation in the using process, has the advantages of no corrosion to a reaction device and high catalytic efficiency, and can effectively avoid the traditional AlCl 3 The base catalyst generates a large amount of sewage in the separation process.)

1. A catalyst for producing styrylated diphenylamine antioxidant, which is characterized in that: is prepared from SO₄ ^2-Modified titanium pillared argil and titanium-based ionic liquid in-situ composite catalyst, wherein SO in catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 50-70 wt%, and the titanium-based ionic liquid is Ti_0.25[MIMPS]₂PMo₁₂O₄₀、Ti_0.50[MIMPS]PMo₁₂O₄₀、Ti_0.25[MIMPS] HPMo₁₂O₄₀One kind of (1).

2. The method of preparing a catalyst for the production of styrenated diphenylamine antioxidants of claim 1, characterized by the steps of:

preparation of titanium pillared argil

Slowly dripping butyl titanate into 1.0mol/L nitric acid solution to ensure that the molar concentration of Ti is 1.0mol/L, treating for 30min under vigorous stirring, standing and aging for 12h to form titanium sol; dispersing carclazyte into deionized water, violently stirring for 2 hours to form a mixture A, slowly adding titanium sol into the mixture A, continuously stirring for 12 hours to obtain a mixture B, carrying out centrifugal separation on the mixture B, sequentially drying for 12 hours at 105 ℃, and roasting for 5 hours at 500 ℃ to obtain titanium pillared carclazyte;

（2）SO₄ ^2-preparation of modified titanium pillared argil

Sequentially adding titanium pillared argil and ammonium sulfate into deionized water, slowly evaporating the obtained mixture to dryness in a 70 ℃ water bath, roasting the evaporated material at 500 ℃ for 5 hours to obtain SO₄ ^2-With 10-15 wt% of SO₄ ^2-Modifying titanium pillared clay;

preparation of ionic liquid precursor MIMPS

Dissolving 1, 3-propane sultone into p-xylene to obtain a mixed solution A, transferring the mixed solution A into a reaction kettle, introducing nitrogen into the reaction kettle for 1h to remove residual oxygen, raising the temperature of the reaction kettle to 80 ℃, dropwise adding N-methylimidazole under the stirring condition of 500r/min, continuously stirring for reaction for 3h to obtain a milky reaction liquid, carrying out reduced pressure suction filtration on the milky reaction liquid, washing the obtained white precipitate with ethyl acetate for three times, and carrying out vacuum drying at 80 ℃ for 12h to obtain white powder solid, namely an ionic liquid precursor, which is marked as MIMPS;

(4) ti-based ionic liquid and SO₄ ^2-In-situ compounding of modified titanium pillared clay

Adding SO₄ ^2-Modified titanium pillared argil, phosphomolybdic acid and TiOSO₄Adding MIMPS into deionized water to obtain

Stirring the mixture C at room temperature for 12h, and then sequentially centrifuging, washing and vacuum drying to obtain SO₄ ^2-The composite catalyst of modified titanium pillared argil and Ti-based solid ionic liquid.

3. The process for preparing a catalyst for the production of styrenated diphenylamine antioxidants of claim 2, characterized in that: in the step (1), the mass-to-volume ratio of the clay to the deionized water in the mixture A is 1g/mL, and the molar mass ratio of the Ti to the clay in the mixture B is 15 mmol/g.

4. The process for preparing a catalyst for the production of styrenated diphenylamine antioxidants of claim 2, characterized in that: in the step (2), the mass-volume ratio of the titanium pillared argil to the deionized water is 1g/mL, and SO is contained in ammonium sulfate₄ ^2-The mass ratio of the titanium-based support clay to the titanium-based support clay is (10-15) to (85-90).

5. The process for preparing a catalyst for the production of styrenated diphenylamine antioxidants of claim 2, characterized in that: in the step (3), the mass ratio of the N-methylimidazole to the 1, 3-propane sultone is such that the mass concentration of the 1:1, 1, 3-propane sultone in p-xylene is 0.15 mol/L.

6. The process for preparing a catalyst for the production of styrenated diphenylamine antioxidants of claim 2, characterized in that: in the step (4), phosphomolybdic acid, TiOSO₄The titanium-based ionic liquid prepared by MIMPS in the reaction process is Ti_0.25[MIMPS]₂PMo₁₂O₄₀、Ti_0.50[MIMPS]PMo₁₂O₄₀、Ti_0.25[MIMPS]HPMo₁₂O₄₀One kind of (1).

7. The process for preparing a catalyst for the production of styrenated diphenylamine antioxidants of claim 2, characterized in that: in the step (4), the ratio of the amounts of MIMPS to phosphomolybdic acid is (1-2) to 1, TiOSO₄The amount ratio of the catalyst to the phosphotungstic acid is (0.25-0.50): 1, and SO is contained in the composite catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 50-70 wt%.

8. A process for producing styrenated diphenylamine using the catalyst of claim 1, characterized in that: adding the composite catalyst, diphenylamine and polymerization inhibitor into a reaction kettle, introducing nitrogen into a system for 1h before reaction to remove residual oxygen, stirring under the protection of nitrogen, heating to 120-150 ℃, dropwise adding alpha-methylstyrene into the reaction system, continuing to react for 2-3 h, carrying out thermal filtration on the reacted mixed solution to separate the catalyst, cooling the filtrate, and then sequentially crystallizing, filtering, washing and drying to obtain the antioxidant rich in 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine.

9. The process for producing styrenated diphenylamine of claim 8, characterized in that: the molar ratio of diphenylamine to alpha-methylstyrene is (0.5-0.7) to 1.0; the mass ratio of the composite catalyst to the diphenylamine is (0.05-0.10) to 1.0; the mass ratio of the polymerization inhibitor to the diphenylamine is (0.002-0.005) to 1.0; the polymerization inhibitor is one of 2, 6-di-tert-butyl-4-methylphenol or 2, 4-dimethyl-6-tert-butylphenol.

Technical Field

The invention belongs to the technical field of chemical additives, relates to a production technology of diphenylamine-based antioxidant, and particularly relates to a preparation method of styryl diphenylamine antioxidant.

Background

Antioxidants are a class of substances that block, inhibit or retard the oxidation or autoxidation process of polymers. The antioxidant can obviously improve the oxidation stability of oil products and prolong the service life of polymers, and is widely applied to the fields of oil products, rubber, plastics and the like. The amine antioxidant is the earliest antioxidant, has excellent high-temperature oxidation resistance and good compatibility with oil products, and is widely used in the fields of oil products, rubber and the like. As an additive of lubricating oil, the amine antioxidant and the antiwear agent are compounded to generate a synergistic effect, so that the oxidation resistance of the lubricating oil can be improved, and the mechanical friction loss of an engine can be reduced; as an anti-aging agent for rubber, the amine antioxidant can prevent rubber from aging caused by external factors such as heat, oxygen and the like, and prolong the service life of the rubber.

The diphenylamine antioxidant is easily affected by operating conditions and reaction environment in the production process, and presents a dark reddish brown color mainly due to oxidation of diphenylamine in the synthesis process and residual discoloration in the product. The diphenylamine residual in the product not only reduces the antioxidant performance of the antioxidant, but also can deepen the color of the product gradually in the storage process due to the overhigh residual quantity, thereby influencing the use of the product in industries such as synthetic rubber and the like.

In the preparation process of the diphenylamine antioxidant, the catalyst is the core of the synthesis reaction technology. Anhydrous AlCl₃And AlCl₃The complex catalyst is an important catalyst in the reaction process, but the AlCl is prepared₃The raw materials of the base catalyst are toxic, and the prepared catalyst is extremely easy to absorb moisture and hydrolyze, and has harsh storage conditions, thereby bringing inconvenience to the actual production. In addition, the catalyst has the defects that the using amount is large, hydrogen chloride gas introduced in the reaction process is easy to corrode equipment, and a large amount of chlorine-containing sewage is generated in the product aftertreatment. Activated clay is a catalyst for producing diphenylamine-based antioxidants, which is commonly used by manufacturers such as Ciba. The activated clay is a catalyst prepared by using clay as a raw material, treating the clay by using sulfuric acid or hydrochloric acid, and then washing and drying the clay. With AlCl₃Compared with the base catalyst, the activated clay is easier to filter and separate, and the product obtained under the catalysis of the activated clay has lighter color. But the activated clay catalyst exists in a larger amount than the catalystLarge size, long reaction time, additional equipment required for secondary alkylation and undesirable product distribution, and the existence of the defects seriously limits the industrialization process of products.

CN1995904A discloses a method for synthesizing dialkyl diphenylamine, which comprises adopting beta zeolite and gamma-Al₂O₃The catalyst is prepared at the reaction temperature of 175-185 ℃ and the reaction pressure of 0.8-1.0 MPa, a fixed bed is adopted for continuous production, the use time of the catalyst exceeds 300 hours, but the content of 4, 4-di-tert-octyldiphenylamine in the obtained product is less than 20%.

CN101745423A discloses a catalyst and a method for alkylating diphenylamine, wherein the catalyst is prepared by contacting activated clay with an aqueous solution of acid with a concentration of less than 20 wt%, dehydrating, and drying. The acid is selected from water-soluble inorganic acid and/or p-toluenesulfonic acid. The catalyst is used for diphenylamine alkylation reaction, but has poor activity, high diphenylamine residual quantity in reaction products and short repeated service life.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method for producing styryl diphenylamine antioxidant, which takes diphenylamine and alpha-methylstyrene as raw materials and SO₄ ^2-The compound of the modified titanium pillared argil and the titanium-based ionic liquid is used as a catalyst to carry out alkylation reaction to prepare a mixture with 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine as a main component, and then the mixture is recrystallized to prepare the antioxidant.

The invention aims to prepare a high-content styrenated diphenylamine product, wherein the relative molar content of 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine in the product is more than or equal to 80 percent. In order to achieve the purpose, the invention is implemented by the following technical scheme:

in one aspect, the invention discloses a catalyst for producing styryl diphenylamine antioxidant, which is prepared from SO₄ ^2-Modified titanium pillared argil and titanium-based ionic liquid in-situ composite catalyst, wherein SO in catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 5070wt% of Ti-based ionic liquid_0.25[MIMPS]₂PMo₁₂O₄₀、Ti_0.50[MIMPS]PMo₁₂O₄₀、Ti_0.25[MIMPS] HPMo₁₂O₄₀One kind of (1).

On the other hand, the invention also discloses a preparation method of the catalyst for producing styryl diphenylamine antioxidant, which is realized by the following steps:

(1) preparation of titanium pillared argil

Slowly dripping butyl titanate into 1.0mol/L nitric acid solution to ensure that the molar concentration of Ti is 1.0mol/L, treating for 30min under vigorous stirring, standing and aging for 12h to form titanium sol serving as a cross-linking agent; dispersing carclazyte into deionized water, violently stirring for 2 hours to form a mixture A, slowly adding titanium sol into the mixture A, continuously stirring for 12 hours to obtain a mixture B, carrying out centrifugal separation on the mixture B, sequentially drying for 12 hours at 105 ℃, and roasting for 5 hours at 500 ℃ to obtain titanium pillared carclazyte;

（2）SO₄ ^2-preparation of modified titanium pillared argil

Sequentially adding titanium pillared argil and ammonium sulfate into deionized water, slowly evaporating the obtained mixture to dryness in a 70 ℃ water bath, roasting the evaporated material at 500 ℃ for 5 hours to obtain SO₄ ^2-With 10-15 wt% of SO₄ ^2-Modifying titanium pillared clay;

(3) preparation of ionic liquid precursor MIMPS

Dissolving 1, 3-propane sultone into p-xylene to obtain a mixed solution A, transferring the mixed solution A into a reaction kettle, introducing nitrogen into the reaction kettle for 1h to remove residual oxygen, raising the temperature of the reaction kettle to 80 ℃, dropwise adding N-methylimidazole under the stirring condition of 500r/min, continuously stirring for reaction for 3h to obtain a milky reaction liquid, carrying out reduced pressure suction filtration on the milky reaction liquid, washing the obtained white precipitate with ethyl acetate for three times, and carrying out vacuum drying at 80 ℃ for 12h to obtain white powder solid, namely an ionic liquid precursor, which is marked as MIMPS;

(4) ti-based ionic liquid and SO₄ ^2-In-situ compounding of modified titanium pillared clay

Adding SO₄ ^2-Modified titanium pillared argil, phosphomolybdic acid and TiOSO₄Adding MIMPS into deionized water to obtain

Stirring the mixture C at room temperature for 12h, and then sequentially centrifuging, washing and vacuum drying to obtain SO₄ ^2-The composite catalyst of modified titanium pillared argil and Ti-based solid ionic liquid.

In a preferred embodiment, in the step (1), the mass-to-volume ratio of the clay to the deionized water in the mixture A is 1g/mL, and the molar mass ratio of the Ti to the clay in the mixture B is 15 mmol/g.

As a preferred embodiment, in the step (2), the mass-to-volume ratio of the titanium pillared argil to the deionized water is 1g/mL, and SO is contained in ammonium sulfate₄ ^2-The mass ratio of the titanium-based support clay to the titanium-based support clay is (10-15) to (85-90).

As a preferable embodiment, in the step (3), the mass concentration of the substance of N-methylimidazole to 1, 3-propane sultone in p-xylene is 0.15mol/L, wherein the mass ratio of the substance of N-methylimidazole to 1, 3-propane sultone is 1:1, 1, 3-propane sultone.

As a preferred embodiment, in step (4), phosphomolybdic acid, TiOSO₄The titanium-based ionic liquid prepared by MIMPS in the reaction process is Ti_0.25[MIMPS]₂PMo₁₂O₄₀、Ti_0.50[MIMPS]PMo₁₂O₄₀、Ti_0.25[MIMPS]HPMo₁₂O₄₀One of (1); further, the ratio of the amounts of MIMPS to phosphomolybdic acid is (1-2): 1, TiOSO₄The amount ratio of the catalyst to the phosphotungstic acid is (0.25-0.50): 1, and SO is contained in the composite catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 50-70 wt%.

In addition, the invention also discloses a method for producing styryl diphenylamine by using the catalyst, which comprises the steps of adding the composite catalyst, diphenylamine and polymerization inhibitor into a reaction kettle, introducing nitrogen into the system for 1h before reaction to expel residual oxygen, stirring under the protection of nitrogen, heating to 120-150 ℃, dropwise adding alpha-methyl styrene into the reaction system, continuing to react for 2-3 h, carrying out thermal filtration on the reacted mixed solution to separate the catalyst, and cooling the filtrate, and then sequentially crystallizing, filtering, washing and drying to obtain the antioxidant rich in 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine.

In a preferred embodiment, the molar ratio of diphenylamine to alpha-methylstyrene is (0.5-0.7) to 1.0; the mass ratio of the composite catalyst to the diphenylamine is (0.05-0.10) to 1.0; the mass ratio of the polymerization inhibitor to the diphenylamine is (0.002-0.005) to 1.0; the polymerization inhibitor is one of 2, 6-di-tert-butyl-4-methylphenol or 2, 4-dimethyl-6-tert-butylphenol.

Compared with the prior art, the invention has the following advantages:

1) the titanium-based solid ionic liquid uses heteropoly acid radicals with multi-charge characteristics as anions and simultaneously uses organic cations, metal cations and protons as counter ions to construct a heteropoly acid functional ionic liquid organic-inorganic hybrid material with B-L dual acidity, so that the overall acid strength of the catalyst can reach the level of super acid, and higher catalytic activity is expressed in the reaction process.

2) SO₄ ^2-Compared with the conventional clay, the specific surface area of the modified titanium pillared clay is obviously increased; and SO₄ ^2-And TiO₂The superacid formed between can be intercalated in highly dispersed form into the interlayer domains of the clay. Thus, SO₄ ^2-The modified titanium pillared argil has good catalytic activity and reaction stability.

3) Titanium-based solid ionic liquid and SO₄ ^2-The modified titanium pillared clay can generate a synergistic effect, and SO on the surface of the modified titanium pillared clay₄ ^2-Can interact with Ti species on the titanium-based solid ionic liquid to generate super acidic catalytic active sites; at the same time, the titanium column supports SiO on the carclazyte₂Can be reacted with PO on solid ionic liquid₄ ^3-Can generate another solid phosphoric acid catalytic active site, titanium-based solid ionic liquid and SO by interaction between the two₄ ^2-Modified titanium column whiteThe catalytic system composed of the earth and the synergistic effect between the two can make up for the reduction of the reaction activity of the whole catalyst caused by the loss or inactivation of one kind of active sites in the reaction process.

4) The prepared composite catalyst can solve the problem of the traditional AlCl₃The base catalyst is easy to lose acidity to cause inactivation in the using process, and the prepared catalyst has the advantages of no corrosion to a reaction device and high catalytic efficiency, and can effectively avoid the traditional AlCl₃The base catalyst generates a large amount of sewage in the separation process.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.

Example 1

A preparation method of an antioxidant catalyst for producing styryl diphenylamine is realized by the following specific steps:

(1) preparation of titanium pillared argil

Slowly dripping butyl titanate into 1.0mol/L nitric acid solution to ensure that the molar concentration of Ti is 1.0mol/L, treating for 30min under the stirring condition of 1000r/min, standing and aging for 12h to form titanium sol as a cross-linking agent; weighing clay, dispersing the clay into deionized water, vigorously stirring for 2 hours to form a mixture A, slowly adding titanium sol into the mixture A, continuously stirring for 12 hours to obtain a mixture B, carrying out centrifugal separation on the obtained mixture, drying for 12 hours at 105 ℃, and roasting for 5 hours at 500 ℃ to obtain titanium pillared clay; wherein the mass volume ratio of the argil to the deionized water in the mixture A is 1g/mL, and the molar mass ratio of the Ti to the argil in the mixture B is 15 mmol/g;

（2）SO₄ ^2-preparation of modified titanium pillared argil

Dispersing titanium pillared argil into deionized water, adding ammonium sulfate, slowly evaporating the obtained mixture to dryness in a 70 ℃ water bath, roasting the evaporated material at 500 ℃ for 5 hours to obtain SO₄ ^2-With an SO content of 10 wt.%₄ ^2-Modifying titanium pillared clay; wherein the mass volume ratio of the titanium pillared argil to the deionized water is 1g/mL, and SO is contained in ammonium sulfate₄ ^2-The mass ratio of the titanium-pillared argil to the titanium-pillared argil is 10:90;

(3) preparation of ionic liquid precursor MIMPS

Weighing 1, 3-propane sultone, dissolving into p-xylene to obtain a mixed solution A, transferring the solution A into a reaction kettle, introducing nitrogen into the reaction kettle for 1h to remove residual oxygen, raising the temperature of the reaction kettle to 80 ℃, dropwise adding N-methylimidazole under the stirring condition of 500r/min, continuously stirring for reaction for 3h to obtain a milky reaction liquid, carrying out reduced pressure suction filtration on the reaction liquid, washing the obtained white precipitate with ethyl acetate for three times, and carrying out vacuum drying at 80 ℃ for 12h to obtain white powder solid, namely MIMPS; wherein the mass ratio of the N-methylimidazole to the 1, 3-propane sultone is 1:1, and the mass concentration of the 1, 3-propane sultone in the paraxylene is 0.15 mol/L;

(4) ti-based ionic liquid and SO₄ ^2-In-situ compounding of modified titanium pillared clay

Adding SO₄ ^2-Modified titanium pillared argil, phosphomolybdic acid and TiOSO₄Adding MIMPS into deionized water to obtain

Stirring the mixture C at room temperature for 12h, and then sequentially centrifuging, washing and vacuum drying to obtain SO₄ ^2-A composite catalyst of modified titanium pillared argil and Ti-based solid ionic liquid; wherein phosphomolybdic acid, TiOSO₄The titanium-based solid ionic liquid prepared by MIMPS in the reaction process is Ti_0.25[MIMPS]₂PMo₁₂O₄₀. Wherein the mass ratio of MIMPS to phosphomolybdic acid is 2:1, TiOSO₄The amount of the material to the phosphotungstic acid is 0.25:1, and SO is contained in the composite catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 50 wt%.

Adding the prepared composite catalyst, diphenylamine and polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol into a reaction kettle according to a ratio, introducing nitrogen into the system for 1h before reaction to remove residual oxygen, stirring under the protection of nitrogen, heating to 120 ℃, dropwise adding alpha-methylstyrene into the reaction system, continuing to react for 3h, carrying out thermal filtration on the reacted mixed solution to separate the catalyst, and after cooling the filtrate, sequentially crystallizing, filtering, washing and drying to obtain a mixture rich in 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine. In the reaction process, the molar ratio of diphenylamine to alpha-methylstyrene is 0.5: 1.0; the mass ratio of the catalyst to the diphenylamine is 0.05: 1.0; the mass ratio of the polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol to the diphenylamine is 0.002: 1.0. The yield of the styrenated diphenylamine mixed product is 96.5 percent by using diphenylamine raw materials as a measuring standard and performing liquid chromatography analysis, wherein the content of 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine is 82.4 percent, and the content of unreacted diphenylamine is 0.15 percent

Example 2

A preparation method of an antioxidant catalyst for producing styryl diphenylamine is realized by the following specific steps:

(1) preparation of titanium pillared argil

Slowly dripping butyl titanate into 1.0mol/L nitric acid solution to ensure that the molar concentration of Ti is 1.0mol/L, treating for 30min under vigorous stirring, standing and aging for 12h to form titanium sol serving as a cross-linking agent. Weighing clay, dispersing into deionized water, vigorously stirring for 2h to form a mixture A, slowly adding titanium sol into the mixture A, continuously stirring for 12h to form a mixture B, centrifugally separating the obtained mixture, drying at 105 ℃ for 12h, and roasting at 500 ℃ for 5h to obtain the titanium pillared clay. Wherein the mass volume ratio of the argil to the deionized water in the mixture A is 1 g/mL; the molar mass ratio of Ti to argil in the mixture B is 15 mmol/g;

（2）SO₄ ^2-preparation of modified titanium pillared argil

Dispersing titanium pillared argil into deionized water, adding ammonium sulfate, slowly evaporating the obtained mixture to dryness in a 70 ℃ water bath, roasting the evaporated material at 500 ℃ for 5 hours to obtain SO₄ ^2-With an SO content of 15 wt.%₄ ^2-Modifying titanium pillared clay; wherein the titanium column is supportedThe mass volume ratio of the soil to the deionized water is 1g/mL, and SO in ammonium sulfate₄ ^2-The mass ratio of the titanium-pillared argil to the titanium-pillared argil is 15:85;

(3) preparation of ionic liquid precursor MIMPS

Weighing 1, 3-propane sultone, dissolving into p-xylene to obtain a mixed solution A, transferring the solution A into a reaction kettle, introducing nitrogen into the reaction kettle for 1h to remove residual oxygen, raising the temperature of the reaction kettle to 80 ℃, dropwise adding N-methylimidazole under the stirring condition of 500r/min, continuously stirring for reaction for 3h to obtain a milky reaction liquid, carrying out reduced pressure suction filtration on the reaction liquid, washing the obtained white precipitate with ethyl acetate for three times, and carrying out vacuum drying at 80 ℃ for 12h to obtain white powder solid, namely MIMPS; wherein the mass ratio of the N-methylimidazole to the 1, 3-propane sultone is 1:1, and the mass concentration of the 1, 3-propane sultone in the paraxylene is 0.15 mol/L;

(4) ti-based ionic liquid and SO₄ ^2-In-situ compounding of modified titanium pillared clay

Adding SO₄ ^2-Modified titanium pillared argil, phosphomolybdic acid and TiOSO₄Adding MIMPS into deionized water to obtain

Stirring the mixture C at room temperature for 12h, and then sequentially centrifuging, washing and vacuum drying to obtain SO₄ ^2-A composite catalyst of modified titanium pillared argil and Ti-based solid ionic liquid; wherein phosphomolybdic acid, TiOSO₄The titanium-based solid ionic liquid prepared by MIMPS in the reaction process is Ti_0.50[MIMPS]PMo₁₂O₄₀. Wherein the mass ratio of MIMPS to phosphomolybdic acid is 1:1, TiOSO₄The amount ratio of the catalyst to the phosphotungstic acid is 0.5:1, and SO is contained in the composite catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 70 wt%.

Adding a catalyst, diphenylamine and a polymerization inhibitor 2, 4-dimethyl-6-tert-butylphenol into a reaction kettle according to a ratio, introducing nitrogen into the system before reaction for 1h to remove residual oxygen, stirring under the protection of nitrogen, heating to 150 ℃, dropwise adding alpha-methylstyrene into the reaction system, continuing to react for 2h, thermally filtering the mixed solution after reaction to separate the catalyst, and after cooling the filtrate, sequentially crystallizing, filtering, washing and drying to obtain a mixture rich in 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine. In the reaction process, the molar ratio of diphenylamine to alpha-methylstyrene is 0.7: 1.0; the mass ratio of the catalyst to the diphenylamine is 0.10: 1.0; the mass ratio of the polymerization inhibitor to the diphenylamine is 0.005:1.0, the yield of the styrenated diphenylamine mixed product is 97.3 percent by liquid chromatography analysis by taking the diphenylamine raw material as a measuring standard, wherein the content of the 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine is 84.6 percent, and the content of the unreacted diphenylamine is 0.12 percent

Example 3

A preparation method of an antioxidant catalyst for producing styryl diphenylamine is realized by the following specific steps:

(1) preparation of titanium pillared argil

Slowly dripping butyl titanate into 1.0mol/L nitric acid solution to ensure that the molar concentration of Ti is 1.0mol/L, treating for 30min under vigorous stirring, standing and aging for 12h to form titanium sol serving as a cross-linking agent. Weighing clay, dispersing into deionized water, vigorously stirring for 2h to form a mixture A, slowly adding titanium sol into the mixture A, continuously stirring for 12h to form a mixture B, carrying out centrifugal separation on the obtained mixture, drying at 105 ℃ for 12, and roasting at 500 ℃ for 5h to obtain titanium pillared clay; wherein the mass volume ratio of the argil to the deionized water in the mixture A is 1 g/mL; the molar mass ratio of Ti to the argil in the mixture B is 15 mmol/g;

（2）SO₄ ^2-preparation of modified titanium pillared argil

Dispersing titanium pillared argil into deionized water, adding ammonium sulfate, slowly evaporating the obtained mixture to dryness in a 70 ℃ water bath, roasting the evaporated material at 500 ℃ for 5 hours to obtain SO₄ ^2-With an SO content of 12 wt.%₄ ^2-Modifying titanium pillared clay; wherein the mass volume ratio of the titanium pillared argil to the deionized water is 1g/mL, and SO is contained in ammonium sulfate₄ ^2-The mass ratio of the titanium-pillared argil to the titanium-pillared argil is 12:88;

(3) preparation of ionic liquid precursor MIMPS

Weighing 1, 3-propane sultone, dissolving into p-xylene to obtain a mixed solution A, transferring the solution A into a reaction kettle, introducing nitrogen into the reaction kettle for 1h to remove residual oxygen, raising the temperature of the reaction kettle to 80 ℃, dropwise adding N-methylimidazole under the stirring condition of 500r/min, continuously stirring for reaction for 3h to obtain a milky reaction liquid, carrying out reduced pressure suction filtration on the reaction liquid, washing the obtained white precipitate with ethyl acetate for three times, and carrying out vacuum drying at 80 ℃ for 12h to obtain white powder solid, namely MIMPS; wherein the mass ratio of the N-methylimidazole to the 1, 3-propane sultone is 1:1, and the mass concentration of the 1, 3-propane sultone in the paraxylene is 0.15 mol/L;

(4) ti-based ionic liquid and SO₄ ^2-In-situ compounding of modified titanium pillared clay

Adding SO₄ ^2-Modified titanium pillared argil, phosphomolybdic acid and TiOSO₄Adding MIMPS into deionized water to obtain

Stirring the mixture C at room temperature for 12h, and then sequentially centrifuging, washing and vacuum drying to obtain SO₄ ^2-A composite catalyst of modified titanium pillared argil and Ti-based solid ionic liquid; wherein phosphomolybdic acid, TiOSO₄The titanium-based solid ionic liquid prepared by MIMPS in the reaction process is Ti_0.25[MIMPS]HPMo₁₂O₄₀. Wherein the mass ratio of MIMPS to phosphomolybdic acid is 1:1, TiOSO₄The amount of the material to the phosphotungstic acid is 0.25:1, and SO is contained in the composite catalyst₄ ^2-The mass fraction of the modified titanium pillared argil is 58 wt%.

Adding the prepared catalyst, diphenylamine and polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol into a reaction kettle according to a ratio, introducing nitrogen into the system before reaction for 1h to remove residual oxygen, stirring under the protection of nitrogen, heating to 135 ℃, dropwise adding alpha-methylstyrene into the reaction system, continuing to react for 2.5h, carrying out thermal filtration on the reacted mixed solution to separate the catalyst, and after cooling the filtrate, sequentially crystallizing, filtering, washing and drying to obtain a mixture rich in 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine. In the reaction process, the molar ratio of diphenylamine to alpha-methylstyrene is 0.60: 1.0; the mass ratio of the catalyst to the diphenylamine is 0.078: 1.0; the mass ratio of the polymerization inhibitor to the diphenylamine is 0.0032:1.0, the yield of the styrenated diphenylamine mixed product is 92.3 percent by liquid chromatography analysis by taking the diphenylamine raw material as a measuring standard, wherein the content of the 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine is 83.6 percent, and the content of the unreacted diphenylamine is 0.14 percent

Comparative example 1

(1) Preparation of titanium pillared argil

Slowly dripping butyl titanate into 1.0mol/L nitric acid solution to ensure that the molar concentration of Ti is 1.0mol/L, treating for 30min under vigorous stirring, standing and aging for 12h to form titanium sol serving as a cross-linking agent. Weighing clay, dispersing into deionized water, vigorously stirring for 2h to form a mixture A, slowly adding titanium sol into the mixture A, continuously stirring for 12h to form a mixture B, carrying out centrifugal separation on the obtained mixture, drying at 105 ℃ for 12, and roasting at 500 ℃ for 5h to obtain titanium pillared clay; wherein the mass volume ratio of the argil to the deionized water in the mixture A is 1 g/mL; the molar mass ratio of Ti to the argil in the mixture B is 15 mmol/g;

（2）SO₄ ^2-preparation of modified titanium pillared argil

Dispersing titanium pillared argil into deionized water, adding ammonium sulfate, slowly evaporating the obtained mixture to dryness in a 70 ℃ water bath, roasting the evaporated material at 500 ℃ for 5 hours to obtain SO₄ ^2-With an SO content of 15 wt.%₄ ^2-Modifying titanium pillared clay; wherein the mass volume ratio of the titanium pillared argil to the deionized water is 1g/mL, and SO is contained in ammonium sulfate₄ ^2-The mass ratio of the titanium-pillared argil to the titanium-pillared argil is 15:85;

the prepared SO₄ ^2-Adding modified titanium pillared argil, diphenylamine and polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol into a reaction kettle in proportion, introducing nitrogen into the system for 1h before reaction to remove residual oxygen, stirring under the protection of nitrogen, heating to 120 ℃, and then dripping into the reaction systemAdding alpha-methyl styrene and continuing to react for 3 hours, carrying out thermal filtration on the mixed solution after reaction to separate the catalyst, and after cooling the filtrate, sequentially carrying out crystallization, filtration, washing and drying to obtain a mixture containing 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine. In the reaction process, the molar ratio of diphenylamine to alpha-methylstyrene is 0.5: 1.0; the mass ratio of the catalyst to the diphenylamine is 0.05: 1.0; the mass ratio of the polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol to the diphenylamine is 0.002: 1.0. The yield of the styrenated diphenylamine mixed product is 72.6 percent by using diphenylamine raw materials as a measuring standard and performing liquid chromatography analysis, wherein the content of 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine is 67.2 percent, and the content of unreacted diphenylamine is 0.94 percent.

Comparative example 2

(1) Preparation of ionic liquid precursor MIMPS

Weighing 1, 3-propane sultone, dissolving into p-xylene to obtain a mixed solution A, transferring the solution A into a reaction kettle, introducing nitrogen into the reaction kettle for 1h to remove residual oxygen, raising the temperature of the reaction kettle to 80 ℃, dropwise adding N-methylimidazole under the stirring condition, continuously stirring for reacting for 3h to obtain a milky reaction liquid, carrying out reduced pressure suction filtration on the reaction liquid, washing the obtained white precipitate with ethyl acetate for three times, and carrying out vacuum drying at 80 ℃ for 12h to obtain white powder solid, namely MIMPS; wherein the mass ratio of the N-methylimidazole to the 1, 3-propane sultone is 1:1, and the mass concentration of the 1, 3-propane sultone in the paraxylene is 0.15 mol/L;

(2) preparation of Ti-based ionic liquid

Phosphomolybdic acid, TiOSO₄Adding MIMPS into deionized water to obtain a mixture, and stirring at room temperature

Reacting for 12h, and then sequentially centrifuging, washing and vacuum drying to obtain the Ti-based solid ionic liquid catalyst Ti_0.25[MIMPS]₂PMo₁₂O₄₀. Wherein the mass ratio of MIMPS to phosphomolybdic acid is 2:1, TiOSO₄The mass ratio to phosphotungstic acid is 0.25: 1;

adding the prepared Ti-based solid ionic liquid, diphenylamine and polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol into a reaction kettle according to a ratio, introducing nitrogen into the system for 1h before reaction to remove residual oxygen, stirring under the protection of nitrogen, heating to 120 ℃, dropwise adding alpha-methylstyrene into the reaction system, continuing to react for 3h, carrying out thermal filtration on the mixed solution after reaction to separate the catalyst, and sequentially crystallizing, filtering, washing and drying after the filtrate is cooled to obtain a mixture containing 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine. In the reaction process, the molar ratio of diphenylamine to alpha-methylstyrene is 0.5: 1.0; the mass ratio of the catalyst to the diphenylamine is 0.05: 1.0; the mass ratio of the polymerization inhibitor 2, 6-di-tert-butyl-4-methylphenol to the diphenylamine is 0.002: 1.0. The yield of the styrenated diphenylamine mixed product is 80.2 percent by using diphenylamine raw materials as a measuring standard and performing liquid chromatography analysis, wherein the content of 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine is 72.3 percent, and the content of unreacted diphenylamine is 0.72 percent.

Example 6

The catalyst prepared in example 1 was subjected to the following cycle test:

TABLE 1 results of cycle testing of catalysts

	4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine content	Diphenylamine content
			Cycle 1	82.1%	0.16%
2 nd cycle	81.7%	0.17%
			Cycle 3	81.2%	0.19%
Cycle 4	80.9%	0.16%

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.