A synthesis process of antioxidant 1135

Abstract

The application relates to the technical field of antioxidants, and particularly discloses a synthesis process of antioxidant 1135, which comprises the following steps: (1) 3,5-methyl ester, a catalyst and a catalytic auxiliary agent are added into a reaction container, nitrogen is used for replacement after heating and temperature rising, stirring is started, and then isooctanol is added for reaction after heat preservation; (2) after the reaction in the step (1) is completed, unreacted isooctanol is removed through distillation, adsorption is carried out by using an adsorption filter aid after temperature reduction, and the antioxidant 1135 can be obtained after filtration; the catalytic auxiliary agent in the above operation is a composition of diatomite and porous alumina in a weight ratio of (3-8):1. The synthesis process of the antioxidant 1135 has a high catalytic reaction process, and can exhibit high product yield and product purity.

Description

Technical Field

[0001] This application relates to the field of antioxidant technology, and more specifically, it relates to a synthesis process for antioxidant 1135. Background Technology

[0002] Antioxidants are indispensable additives in polymer production and processing. Without antioxidants, polymers will undergo rapid oxidative degradation during processing and use. Antioxidant 1135, also known as isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, is a high-performance liquid hindered phenolic antioxidant that is widely applicable to various polymers. It has unique functions, especially in the antioxidant properties of polyurethane and its polymeric polyols in the automotive industry and as an antioxidant for lubricating oils.

[0003] Currently, there are two commonly used methods for synthesizing antioxidant 1135. One method involves transesterification of 3,5-dimethyl ester with isopropanol, while the other method does not use 3,5-dimethyl ester as an intermediate but instead uses 2,6-ditert-butylphenol with acrylate. For example, the invention patent with authorization announcement number CN104447333B discloses a method for producing liquid hindered phenolic antioxidant 1135, including the following steps: 1) a certain amount of methyl 3,5-ditert-butyl-4-hydroxyphenylpropionate ( 1) 3,5-methyl ester), isooctyl alcohol, and catalyst are added to a reactor, purged with nitrogen, and the temperature is controlled between 140 and 170°C, with a vacuum of -0.04 to -0.08 MPa. Methanol generated during the reaction is extracted, and the reaction is carried out for 4-8 hours. 2) The temperature is raised to 175-180°C, the vacuum is controlled below -0.096 MPa, and distillation is carried out for 90-120 minutes. The temperature is then lowered to 80-90°C, and an appropriate amount of organic acid is added to the reactor to neutralize the residual catalyst. The mixture is filtered, and the filtrate is taken as the target product. In step 1), the preferred reaction process is to first raise the temperature to 140-150°C, adjust the vacuum to -0.04 to -0.05 MPa, and react for 1-3 hours. Then, the temperature is further raised to 160-170°C, the vacuum is adjusted to -0.07 to -0.08 MPa, and the reaction is carried out for 3-5 hours.

[0004] Regarding the aforementioned technologies, the inventors believe that although the production of antioxidant 1135 can achieve high product yield and purity, the catalytic reaction process is relatively long, resulting in a long overall process time. Forcibly increasing the catalytic reaction process would have an adverse effect on product yield and purity.

[0005] Therefore, there is an urgent need to propose a solution to address the aforementioned technical problems. Summary of the Invention

[0006] In order to improve the catalytic reaction process in the production of antioxidant 1135 and obtain excellent product yield and purity, this application provides a synthesis process for antioxidant 1135.

[0007] This application provides a synthesis process for antioxidant 1135, which adopts the following technical solution:

[0008] A process for synthesizing antioxidant 1135 includes the following steps:

[0009] (1) Take 3,5-methyl ester, catalyst and catalyst auxiliary agent into the reaction vessel, purge with nitrogen, heat and stir, then keep warm and add isooctanol to react;

[0010] (2) After the reaction in step (1) is completed, the unreacted isooctyl alcohol is removed by distillation, and after cooling, it is adsorbed using an adsorption filter aid. After filtration, antioxidant 1135 can be obtained.

[0011] The catalytic aid in the above operation is a combination of diatomaceous earth and porous alumina in a weight ratio of (3-8):1.

[0012] By adopting the above technical solution, diatomaceous earth possesses a unique porous structure with a large number of silanol groups on its surface, exhibiting high thermal and chemical stability. Porous alumina, on the other hand, has abundant micropores, a large specific surface area, and good thermal stability. When diatomaceous earth and porous alumina are combined in a specific weight ratio to form a catalytic aid, the catalyst forms a multi-level loading on both materials, significantly improving the overall activity, selectivity, and stability of the catalyst, thereby significantly shortening the entire catalytic reaction process. Simultaneously, the synergistic effect of diatomaceous earth and porous alumina ensures the orderly reaction of 3,5-methyl ester and isooctyl alcohol, playing a regulatory role in the highly catalytic process and contributing to excellent product yield and purity. Furthermore, in the entire synthesis process of antioxidant 1135, the mixture of 3,5-methyl ester, catalyst, and catalytic aid is first heated, and then isooctanol is added to react under heat. The preceding heating promotes the full combination of the catalyst and catalytic aid and brings about a certain activation effect. Thus, when isooctanol is introduced in the subsequent reaction, a high catalytic reaction process can be obtained, ensuring that the obtained antioxidant 1135 has excellent product yield and product purity.

[0013] Preferably, the weight ratio of diatomaceous earth to porous alumina is 5:1.

[0014] By adopting the above technical solution, the catalytic catalytic auxiliary agent composed of diatomaceous earth and porous alumina in the above weight ratio has a better synergistic effect. It performs well in accelerating the catalytic reaction process and ensuring the product yield and purity. As a result, the synthesis process of antioxidant 1135 has a better application effect and strong industrial applicability.

[0015] Preferably, the diatomaceous earth has a particle size of 20-50 μm and a specific surface area of ​​40-60 m². 2 / g, with a porosity of 60-70%; the porous alumina has a particle size of 60-80μm and a specific surface area of ​​200-300m². 2 / g, with a porosity of 30-50%.

[0016] By adopting the above technical solution, when diatomaceous earth and porous alumina of the above specifications are used in combination, the catalyst can not only be stably loaded on it, but also form a more suitable multi-stage supported catalytic system. It has strong compatibility in giving full play to the synergistic properties of diatomaceous earth and porous alumina and ensuring the stable progress of the reaction, thereby enabling the catalytic auxiliary agent to play a better application effect, that is, to improve the catalytic reaction process in the production of antioxidant 1135, and ultimately obtain excellent product yield and product purity.

[0017] Preferably, the catalyst is one or a combination of several of the following: dibutyltin oxide, aluminum triisopropoxide, tetrabutyl titanate, potassium acetate, and 2-ethylhexyl titanate.

[0018] By adopting the above technical solutions, the catalyst reduces the activation energy of the reaction, enabling the reaction, which was originally difficult to carry out, to proceed under milder conditions, thereby accelerating the reaction rate and increasing the yield. All of the above-mentioned catalysts can be applied to the synthesis process of antioxidant 1135 and bring excellent and stable corresponding effects.

[0019] Preferably, the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of (6-9):(1-3):1.

[0020] By adopting the above technical solutions, dibutyltin oxide possesses thermal stability and resistance to hydrolysis, as well as high catalytic activity; aluminum triisopropoxide exhibits good thermal and chemical stability, enabling catalytic reactions at high temperatures and pressures; tetrabutyl titanate exhibits a fast catalytic reaction rate, and side reactions are difficult to occur during the process; and combining dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in appropriate weight ratios as a catalyst can achieve a more comprehensive catalytic effect and form a good synergistic effect with the catalytic auxiliary agents composed of diatomaceous earth and porous alumina. This improves the catalytic reaction process in the production of antioxidant 1135 while achieving better product yield and purity, resulting in a more effective application of the antioxidant 1135 synthesis process.

[0021] Preferably, the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of 8:2:1.

[0022] By adopting the above technical solution, the synergistic effect between the above weight ratio of dibutyltin oxide, aluminum triisopropoxide and tetrabutyl titanate and the catalyst auxiliary is better when used as a catalyst, resulting in better performance. Under the premise of obtaining a high catalytic reaction process, the product yield and product purity are better.

[0023] Preferably, the amount of catalyst used is 0.4-0.6% of the mass of 3,5-methyl ester.

[0024] Preferably, the amount of the catalyst auxiliary is 1.5-2.2% of the mass of 3,5-methyl ester.

[0025] Preferably, the mass ratio of the 3,5-methyl ester to isooctyl alcohol is 1:(1.5-1.7).

[0026] By adopting the above technical solution, the amount of catalyst, the amount of catalyst auxiliary agent, and the mass ratio of 3,5-methyl ester to isooctanol not only enable the catalyst and catalyst auxiliary agent to fully synergistically act on the reaction of 3,5-methyl ester and isooctanol, but also meet the requirements of high catalytic reaction process, which is conducive to obtaining higher product yield and product purity, thereby ensuring that the synthesis process of antioxidant 1135 has excellent and stable applicability.

[0027] The preferred synthesis process of antioxidant 1135 specifically includes the following steps:

[0028] (1) Take 3,5-methyl ester, catalyst and catalyst auxiliary agent into the reaction vessel, purge with nitrogen, heat to 145-175℃ and start stirring for 40-60 min, then keep at 175-180℃ and add isooctol to react for 80-100 min.

[0029] (2) After the reaction in step (1) is completed, the unreacted isooctanol is removed by distillation at 185-195℃ for 10-30 min. After cooling, an adsorption filter aid is used for adsorption. After filtration, antioxidant 1135 can be obtained.

[0030] The catalyst aid in the above operation is a combination of diatomaceous earth and porous alumina in a weight ratio of (3-7):1.

[0031] By adopting the above technical solution and selecting the corresponding temperature and time control in the above operation, the catalyst and catalytic auxiliary agent can be fully combined in the process, and bring about corresponding excellent effects in the reaction of 3,5-methyl ester and isooctyl alcohol. This makes the interaction between the operation and the raw materials more compatible, and thus improves the catalytic reaction process in the production of antioxidant 1135 while achieving excellent product yield and product purity.

[0032] In summary, this application has the following beneficial effects:

[0033] 1. Because this application uses a catalytic aid composed of diatomaceous earth and porous alumina to form a multi-level loading of the catalyst, it not only significantly improves the overall activity, selectivity and stability of the catalyst, but also brings a regulatory effect in the catalytic reaction process, which is beneficial to improve the catalytic reaction process in the production of antioxidant 1135, and can also obtain excellent product yield and product purity.

[0034] 2. Since this application uses dibutyltin oxide, aluminum triisopropoxide and tetrabutyl titanate in a corresponding weight ratio as a catalyst, the synergistic effect between the catalyst and the catalyst auxiliary is better, and it is more suitable for the reaction process of 3,5-methyl ester and isooctyl alcohol. Thus, while improving the catalytic reaction process in the production of antioxidant 1135, it can obtain better product yield and product purity. Detailed Implementation

[0035] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0036] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this application are commercially available.

[0037] Diatomite was purchased from Jiayuan Mineral Products Processing Plant in Lingshou County;

[0038] The porous alumina was purchased from Jiangxi Zhongxu Technology Co., Ltd., and conforms to the standard HG / T3927-2020.

[0039] The adsorption filter aid is activated clay, specifically activated clay 1060 purchased from Guangzhou Yifeng Chemical Technology Co., Ltd.

[0040] Example

[0041] Example 1

[0042] A process for synthesizing antioxidant 1135 includes the following steps:

[0043] (1) Take 3,5-methyl ester, catalyst and catalyst auxiliary agent into the reaction vessel, purge with nitrogen, heat to 160℃ and start stirring for 50 min, then keep at 177.5℃ and add isooctyl alcohol to react for 90 min;

[0044] (2) After the reaction in step (1) is completed, the unreacted isooctyl alcohol is removed by distillation at 190℃ for 10-30 min. After cooling, an adsorption filter aid is used for adsorption. After filtration, antioxidant 1135 can be obtained.

[0045] Note: The catalyst in the above operation is a composition of diatomaceous earth and porous alumina in a weight ratio of 5:1; the diatomaceous earth has a particle size of 35 μm and a specific surface area of ​​50 m². 2 / g, porosity 65%; porous alumina particle size 70μm, specific surface area 250m² / g. 2 / g, with a porosity of 40%; the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide and tetrabutyl titanate in a weight ratio of 8:2:1; the amount of catalyst is 0.5% of the mass of 3,5-methyl ester; the amount of catalyst aid is 1.85% of the mass of 3,5-methyl ester; the mass ratio of 3,5-methyl ester to isooctyl alcohol is 1:1.6.

[0046] Example 2

[0047] A synthesis process for antioxidant 1135, which differs from that of Example 1, specifically includes the following steps:

[0048] (1) Add 3,5-methyl ester, catalyst and catalyst auxiliary to the reaction vessel, purge with nitrogen, heat to 145°C and stir for 60 min, then keep at 180°C and add isooctyl alcohol to react for 80 min.

[0049] (2) After the reaction in step (1) is completed, the unreacted isooctanol is removed by distillation at 185°C for 30 minutes. After cooling, an adsorption filter aid is used for adsorption. After filtration, antioxidant 1135 can be obtained.

[0050] Example 3

[0051] A synthesis process for antioxidant 1135, which differs from that of Example 1, specifically includes the following steps:

[0052] (1) Take 3,5-methyl ester, catalyst and catalyst auxiliary agent into the reaction vessel, purge with nitrogen, heat to 175℃ and start stirring for 40 min, then keep at 175℃ and add isooctol to react for 100 min.

[0053] (2) After the reaction in step (1) is completed, the unreacted isooctyl alcohol is removed by distillation at 195°C for 10 minutes. After cooling, an adsorption filter aid is used for adsorption. After filtration, antioxidant 1135 can be obtained.

[0054] Example 4

[0055] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the catalytic aid is a composition of diatomaceous earth and porous alumina in a weight ratio of 3:1.

[0056] Example 5

[0057] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalytic aid is a composition of diatomaceous earth and porous alumina in a weight ratio of 8:1.

[0058] Example 6

[0059] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalytic aid is a composition of diatomaceous earth and porous alumina in a weight ratio of 5.5:1.

[0060] Example 7

[0061] The synthesis process of antioxidant 1135 differs from that in Example 1 in that the diatomaceous earth has a particle size of 20 μm and a specific surface area of ​​40 m². 2 / g, porosity 60%; porous alumina particle size 60μm, specific surface area 200m² / g. 2 / g, with a porosity of 30%.

[0062] Example 8

[0063] The synthesis process of antioxidant 1135 differs from that in Example 1 in that the diatomaceous earth has a particle size of 50 μm and a specific surface area of ​​60 m². 2 / g, porosity 70%; porous alumina particle size 80μm, specific surface area 300m² / g. 2 / g, with a porosity of 50%.

[0064] Example 9

[0065] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of 7.5:2:1.

[0066] Example 10

[0067] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of 6:1:1.

[0068] Example 11

[0069] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of 9:3:1.

[0070] Example 12

[0071] A synthesis process for antioxidant 1135 differs from that of Example 1 in that dibutyltin oxide is not used in the catalyst.

[0072] Example 13

[0073] A synthesis process for antioxidant 1135 differs from that of Example 1 in that aluminum triisopropoxide is not used in the catalyst.

[0074] Example 14

[0075] A synthesis process for antioxidant 1135 differs from that of Example 1 in that tetrabutyl titanate is not used in the catalyst.

[0076] Example 15

[0077] A synthesis process for antioxidant 1135 differs from that of Example 1 in that dibutyltin oxide and tetrabutyl titanate are not used in the catalyst.

[0078] Example 16

[0079] A synthesis process for antioxidant 1135 differs from that of Example 1 in that aluminum triisopropoxide and tetrabutyl titanate are not used in the catalyst.

[0080] Example 17

[0081] A synthesis process for antioxidant 1135 differs from that of Example 1 in that dibutyltin oxide and aluminum triisopropoxide are not used in the catalyst.

[0082] Example 18

[0083] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the amount of catalyst used is 0.4% of the mass of 3,5-methyl ester.

[0084] Example 19

[0085] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the amount of catalyst used is 0.6% of the mass of 3,5-methyl ester.

[0086] Example 20

[0087] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the amount of catalyst auxiliary is 1.5% of the mass of 3,5-methyl ester.

[0088] Example 21

[0089] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the amount of catalyst auxiliary is 2.2% of the mass of 3,5-methyl ester.

[0090] Example 22

[0091] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the mass ratio of 3,5-methyl ester to isooctyl alcohol is 1:1.5.

[0092] Example 23

[0093] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the mass ratio of 3,5-methyl ester to isooctyl alcohol is 1:1.7.

[0094] Comparative Example

[0095] Comparative Example 1

[0096] A synthesis process for antioxidant 1135 differs from that of Example 1 in that no catalytic aid is used in step (1).

[0097] Comparative Example 2

[0098] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the catalytic aid does not contain diatomaceous earth.

[0099] Comparative Example 3

[0100] A synthesis process for antioxidant 1135 differs from that of Example 1 in that the catalyst auxiliary does not contain porous alumina.

[0101] Comparative Example 4

[0102] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalytic aid is a composition of diatomaceous earth and porous alumina in a weight ratio of 2.5:1.

[0103] Comparative Example 5

[0104] A synthesis process for antioxidant 1135 differs from that in Example 1 in that the catalytic aid is a composition of diatomaceous earth and porous alumina in a weight ratio of 8.5:1.

[0105] Performance testing method: The synthesis process of antioxidant 1135 described in Examples 1-23 and Comparative Examples 1-5 was applied, and the product yield and product purity were calculated respectively.

[0106] Product yield = Actual mass of antioxidant 1135 / Theoretical yield;

[0107] Product purity = mass of active ingredient (antioxidant 1135) / total mass of mixture.

[0108] Table 1. Application test results of Examples 1-23 and Comparative Examples 1-5

[0109] Synthesis process of antioxidant 1135 Product yield (%) Product purity (%) Example 1 99.73 99.47 Example 2 99.54 99.28 Example 3 99.62 99.36 Example 4 99.67 99.41 Example 5 99.58 99.32 Example 6 99.60 99.34 Example 7 99.64 99.38 Example 8 99.57 99.31 Example 9 99.69 99.43 Example 10 99.63 99.37 Example 11 99.59 99.33 Example 12 99.43 99.17 Example 13 99.36 99.11 Example 14 99.41 99.14 Example 15 99.25 99.01 Example 16 99.24 99.04 Example 17 99.28 99.03 Example 18 99.61 99.35 Example 19 99.55 99.29 Example 20 99.68 99.42 Example 21 99.70 99.44 Example 22 99.65 99.39 Example 23 99.71 99.45 Comparative Example 1 94.56 94.18 Comparative Example 2 96.51 96.32 Comparative Example 3 96.35 96.07 Comparative Example 4 98.27 98.21 Comparative Example 5 98.34 98.27

[0110] As can be seen from Examples 1-3 and Comparative Examples 1-3, and Table 1, the use of a catalytic aid composed of diatomaceous earth and porous alumina can significantly shorten the catalytic reaction time, thereby improving the catalytic reaction process. Simultaneously, at a higher catalytic reaction rate, higher product yield and purity can be obtained, making the synthesis process of antioxidant 1135 highly applicable. Without the catalytic aid, the product yield and purity obtained from application tests were significantly lower, indicating that the catalytic reaction could not be completed in a short time, failing to achieve the goal of improving the catalytic reaction process. While using either diatomaceous earth or porous alumina alone as a catalytic aid can improve product yield and purity to some extent, the effect is far less significant than that of the combined application of diatomaceous earth and porous alumina. Therefore, only when diatomaceous earth and porous alumina are used in combination can the catalytic reaction process in the production of antioxidant 1135 be improved, resulting in excellent product yield and purity.

[0111] Combining Examples 1 and 4-6 with Table 1, it can be seen that when the weight ratio of diatomaceous earth to porous alumina is 5:1, the application effect of the catalytic aid is better, showing outstanding performance in accelerating the catalytic reaction process and ensuring product yield and purity. Combining Comparative Examples 4-5 with Table 1, it can be seen that when the weight ratio of diatomaceous earth to porous alumina exceeds the range of (3-8):1 to form the catalytic aid, the product yield and purity obtained in the application test are significantly lower. This indicates that, based on the application of diatomaceous earth and porous alumina as a catalytic aid, it needs to be used within a specific ratio range to bring about a more outstanding and significant application effect.

[0112] Based on Examples 1 and 7-8 and Table 1, it can be seen that the particle size of diatomaceous earth is 20-50 μm and the specific surface area is 40-60 m². 2 / g, with a porosity of 60-70%; the porous alumina has a particle size of 60-80μm and a specific surface area of ​​200-300m². 2 / g, with a porosity of 30-50%, allows the catalytic aid to achieve better application results, and the product yield and purity obtained through application testing are excellent.

[0113] Combined with Examples 1 and 9-11 and Table 1, it can be seen that when the catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of (6-9):(1-3):1, it can exert excellent and stable effects. The product yield and purity obtained by application test are both high. Among them, when the weight ratio of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate is 8:2:1, the effect of the catalyst application is better. Referring to Examples 12-17 and Table 2, it can be seen that when any one or two of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate are used as catalysts, the product yield and purity obtained from application tests are significantly reduced, indicating poor synergy between the catalyst and the catalytic auxiliary agent. Therefore, this application uses a combination of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in the corresponding weight ratio as a catalyst, which improves the synergy between the catalyst and the catalytic auxiliary agent. This allows for better product yield and purity while improving the catalytic reaction process in the production of antioxidant 1135.

[0114] Combining Examples 1 and 18-23 with Table 1, it can be seen that in the synthesis process of antioxidant 1135, the amount of catalyst used is 0.4-0.6% of the mass of 3,5-methyl ester, the amount of catalyst auxiliary is 1.5-2.2% of the mass of 3,5-methyl ester, and the mass ratio of 3,5-methyl ester to isooctanol is 1:(1.5-1.7). All of these are suitable for the high catalytic reaction process and can obtain stable and high product yield and product purity.

[0115] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A synthesis process for antioxidant 1135, characterized in that, Includes the following steps: (1) Take 3,5-methyl ester, catalyst and catalyst auxiliary agent into the reaction vessel, purge with nitrogen, heat and stir, then keep warm and add isooctyl alcohol to react; (2) After the reaction in step (1) is completed, the unreacted isooctyl alcohol is removed by distillation, and after cooling, it is adsorbed by an adsorption filter aid. After filtration, antioxidant 1135 can be obtained. The catalytic adjuvant in the above operation is a combination of diatomite and porous alumina in a weight ratio of 5:1; the diatomite has a particle size of 20-50 μm, a specific surface area of 40-60 m 2 / g, and a porosity of 60-70%; the porous alumina has a particle size of 60-80 μm, a specific surface area of 200-300 m 2 / g, and a porosity of 30-50%. The catalyst is a mixture of dibutyltin oxide, aluminum triisopropoxide, and tetrabutyl titanate in a weight ratio of 8:2:1; The amount of catalyst used is 0.4-0.6% of the mass of 3,5-methyl ester; The amount of the catalyst auxiliary is 1.5-2.2% of the mass of 3,5-methyl ester; The mass ratio of the 3,5-methyl ester to isooctyl alcohol is 1:(1.5-1.7).

2. The synthesis process of antioxidant 1135 according to claim 1, characterized in that: Specifically, the following steps are included: (1) Take 3,5-methyl ester, catalyst and catalyst auxiliary agent into the reaction vessel, purge with nitrogen, heat to 145-175℃ and start stirring for 40-60 min, then keep warm at 175-180℃ and add isooctyl alcohol to react for 80-100 min; (2) After the reaction in step (1) is completed, the unreacted isooctanol is removed by distillation at 185-195℃ for 10-30 min. After cooling, an adsorption filter aid is used for adsorption. After filtration, antioxidant 1135 can be obtained.