Preparation method of liquid hindered phenol antioxidant 1135

Abstract

The invention provides a preparation method of a liquid hindered phenol antioxidant 1135, which comprises the following steps: adding 3, 5-di-tert-butyl-4-hydroxy phenyl methyl propionate, isooctanol and a catalyst into an ultrasonic reactor, under the conditions of continuous nitrogen purging and ultrasonic treatment, controlling the vacuum degree in the reactor to be Pv1 and the reaction temperature to be T1, and reacting to obtain the liquid hindered phenol antioxidant 1135. Extracting methanol generated in the reaction process; wherein the catalyst is a combined catalyst formed by loading palladium acetate and zinc trifluoromethanesulfonate on a porous carrier; after the reaction is finished, the temperature is adjusted to T2, the vacuum degree is adjusted to Pv2, distillation is performed, and unreacted isooctanol is removed; and cooling the temperature of the reactant to T3, filtering the reactant, and taking the filtrate to obtain the antioxidant 1135. According to the method disclosed by the invention, the reaction can be carried out at the temperature lower than 100 DEG C, the catalytic system effect is good, and the obtained product is high in purity, high in yield, good in stability and excellent in performance.

Description

Technical Field

[0001] The invention relates to the technical field of phenolic antioxidants, and in particular to a method for preparing a liquid hindered phenolic antioxidant 1135. Background Art

[0002] Liquid hindered phenol antioxidant 1135 (2-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) is an excellent antioxidant widely used in various polymers. It has unique functions in the antioxidant of polyurethane and its polymer polyols in the automotive industry and as an antioxidant for lubricating oils. Therefore, liquid antioxidant 1135 is a new type of high-efficiency liquid antioxidant that cannot be replaced by powdered antioxidants. Its research and development is of great significance.

[0003] There are currently a variety of methods for preparing 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate isooctyl ester. For example, using organic tin as a catalyst, 3,5-methyl ester and isooctyl alcohol undergo an ester exchange reaction. The reaction is easy to carry out, but the tin catalyst is difficult to remove, has an adverse effect on the environment, and the product tends to turn yellow after being left for a period of time.

[0004] Using aluminum isopropoxide as a catalyst, 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid methyl ester (3,5-methyl ester) and isooctyl alcohol undergo an ester exchange reaction to obtain 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid isooctyl ester. Although this method uses a non-tin catalyst, it requires acid washing and water washing during post-treatment, generates a large amount of wastewater, and is not conducive to environmental protection.

[0005] Using zinc acetate as a catalyst, 3,5-methyl ester and isooctyl alcohol undergo an ester exchange reaction to obtain 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate isooctyl ester. Although this method does not require a large amount of water washing, the reaction process takes too long, requiring 6 to 12 hours, and the temperature for extracting isooctyl alcohol is too high, reaching 180°C, resulting in huge energy consumption losses.

[0006] Moreover, the above methods are all carried out at a temperature higher than 100°C. The ester exchange reaction under high temperature conditions is prone to produce side reactions and impurities. The most obvious manifestation is that the product directly appears yellow. When the catalytic system is not effective, side reaction impurities will also be produced, affecting the stability of the product, thereby affecting the final performance of the product.

[0007] Prior art literature:

[0008] US Patent: US3330859

[0009] US Patent: US5892097

[0010] US Patent: US5481023

[0011] Chinese patent: CN107954863. Summary of the invention

[0012] The purpose of the present invention is to provide a method for preparing a liquid hindered phenol antioxidant 1135 in view of the deficiencies in the prior art. By using a combined catalyst consisting of palladium acetate and zinc trifluoromethanesulfonate loaded on a porous carrier and combined with ultrasonic treatment, the reaction can be carried out at a temperature below 100° C., and the catalytic system has a good effect, the obtained product has high purity, high yield, good stability, and excellent product performance.

[0013] According to the purpose of the present invention, a method for preparing a liquid hindered phenol antioxidant 1135 is provided, comprising the following steps:

[0014] (1) placing methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, isooctyl alcohol and a catalyst into an ultrasonic reactor, and under conditions of continuous nitrogen purging and ultrasonication, controlling the vacuum degree in the reactor to be at Pv1 and the reaction temperature to be at T1, reacting, and extracting methanol generated during the reaction; wherein the catalyst is a combined catalyst in which palladium acetate and zinc trifluoromethanesulfonate are loaded on a porous carrier;

[0015] (2) After the reaction in step (1) is completed, the temperature is adjusted to T2, the vacuum degree is adjusted to Pv2, and distillation is performed to remove unreacted isooctyl alcohol;

[0016] (3) After step (2), the temperature of the reactants is cooled to T3, the reactants are filtered, and the filtrate is collected to obtain antioxidant 1135.

[0017] As an optional embodiment, the preparation process of the catalyst comprises the following steps:

[0018] The carrier is calcined to obtain a pretreated carrier; palladium acetate is dissolved in deionized water to obtain a palladium acetate solution; zinc trifluoromethanesulfonate is dissolved in deionized water to obtain a zinc trifluoromethanesulfonate solution;

[0019] The pretreated support is immersed in a palladium acetate solution, and after the immersion is completed, it is dried at a constant temperature to obtain a first intermediate;

[0020] The first intermediate is immersed in a zinc trifluoromethanesulfonate solution, and after the immersion is completed, it is dried at a constant temperature to obtain a second intermediate;

[0021] The second intermediate is calcined to obtain a combined catalyst.

[0022] As an optional embodiment, the concentration of the palladium acetate solution is 20 mg / mL to 40 mg / mL, and the concentration of the zinc trifluoromethanesulfonate solution is 50 mg / mL to 70 mg / mL.

[0023] As an optional embodiment, the pretreated support is immersed in a palladium acetate solution at room temperature for 4 to 6 hours, and then dried at a constant temperature of 85° C. to 95° C. for 7 to 9 hours to obtain a first intermediate.

[0024] As an optional embodiment, the first intermediate is immersed in a zinc trifluoromethanesulfonate solution at room temperature for 2 hours to 4 hours, and then dried at a constant temperature of 85° C. to 95° C. for 7 hours to 9 hours to obtain a second intermediate.

[0025] As an optional embodiment, the carrier includes silicon oxide, the carrier is calcined at a temperature of 400°C for 3 hours to 4 hours, and the second intermediate is calcined at a temperature of 400°C to 700°C for 4 hours to 5 hours.

[0026] As an optional embodiment, the molar ratio of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate to isooctyl alcohol is 1:(1.3-1.5), and the amount of the catalyst used is 0.3%-0.5% of the mass of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

[0027] As an optional implementation, in step (1), the value of T1 is 70°C to 90°C, the value of Pv1 is -0.02MPa to -0.04MPa, the ultrasonic frequency is 60HZ to 100HZ, and the reaction time is 0.4h to 0.6h.

[0028] As an optional embodiment, in step (2), the value of T2 is 130°C to 140°C, the value of Pv2 is -0.08MPa to -0.1MPa, and the distillation time is 0.3h to 0.6h.

[0029] As an optional implementation, in step (3), the value of T3 is 20°C to 30°C.

[0030] It can be seen from the above technical scheme of the present invention that the preparation method of the liquid hindered phenol antioxidant 1135 proposed by the present invention adopts a combined catalyst composed of palladium acetate and zinc trifluoromethanesulfonate loaded on a porous carrier. The palladium acetate and zinc trifluoromethanesulfonate interact with each other on the carrier to form a complex, which can form a specific interaction with the reactant molecules, change the reaction pathway, and reduce the reaction activation energy. In addition, the complex can selectively promote the key steps in the synthesis reaction, inhibit unnecessary side reactions, and allow more energy to be concentrated on the main reaction. On this basis, combined with ultrasonic treatment, the breaking of the chemical bonds of the reactants and the formation of new chemical bonds are accelerated to promote the reaction. At the same time, the ultrasonic action provides additional energy, which increases the effective collision between molecules and improves the reaction rate. In this way, the reaction can be carried out at a lower temperature and has a better catalytic effect.

[0031] In addition, ultrasonic treatment enables the combined catalyst to form more active sites, and the effects of ultrasound such as micro-jet may modify the surface structure of the catalyst to make it more compatible with the reactants, which allows the complex to play a catalytic role in a more suitable environment, further improving its effect of reducing the activation energy of the reaction, thereby achieving efficient reaction at a lower temperature;

[0032] The synergistic effect of complex catalysis and ultrasonic treatment accelerates the reaction process and shortens the time required for the reaction to reach equilibrium. In a shorter period of time, the reaction system does not need to be maintained at a high temperature for a long time to ensure the reaction, thus reducing the overall temperature requirement of the reaction.

[0033] At the same time, the lower reaction temperature ensures the stability of the combined catalyst, avoids the deactivation of the catalyst caused by the reaction of the complex with impurities at high temperature, and ensures the catalytic activity; combined with the cavitation effect of ultrasound, the reactants are mixed more evenly and the reaction is more complete, reducing the occurrence of side reactions caused by local overheating or uneven concentration of reactants, thereby reducing the risk of product discoloration;

[0034] At the same time, the catalyst carrier itself also has a certain adsorption property, which can adsorb some impurities or intermediates produced during the reaction that may cause discoloration, thereby reducing their impact on the product color;

[0035] In this way, the catalytic system can be operated at a lower temperature, avoiding side reactions and impurities caused by high temperature, which cause the product to directly appear yellow, and making the catalytic system more effective, avoiding side reactions and impurities caused by poor catalytic effect, which affect the stability of the product and cause it to appear yellow during long-term storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a process flow chart of the preparation method of the liquid hindered phenol antioxidant 1135 of the present invention.

[0037] Figure 2 is a picture of a sample prepared in an example of the present invention.

[0038] Figure 3 This is a picture of the sample in the comparative example of the present invention after being placed for one month. DETAILED DESCRIPTION

[0039] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0040] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways.

[0041] The present invention aims to provide a method for preparing a liquid hindered phenol antioxidant 1135. By constructing a catalytic system combining a combined catalyst and ultrasonic treatment, the problem of a yellow product due to the need to carry out the reaction at a high temperature and an unstable product due to poor catalytic effect is solved. The obtained product has high purity, high yield and good stability.

[0042] Combination Figure 1 As shown, the preparation method of the exemplary liquid hindered phenol antioxidant 1135 of the present invention comprises the following steps:

[0043] (1) 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid methyl ester, isooctyl alcohol and a catalyst are placed in a reactor with ultrasound, and under the conditions of continuous nitrogen purging and ultrasound, the vacuum degree in the reactor is controlled at Pv1 and the reaction temperature is controlled at T1 to carry out the reaction, and methanol generated during the reaction is extracted; wherein the catalyst is a combined catalyst in which palladium acetate and zinc trifluoromethanesulfonate are loaded on a porous carrier.

[0044] (2) After the reaction in step (1) is completed, the temperature is adjusted to T2, the vacuum degree is adjusted to Pv2, and distillation is performed to remove unreacted isooctyl alcohol.

[0045] (3) After step (2), the temperature of the reactants is cooled to T3, the reactants are filtered, and the filtrate is collected to obtain antioxidant 1135.

[0046] As an optional example, the preparation process of the catalyst includes the following steps:

[0047] Calcination activation of the supported catalyst carrier: Take the prepared carrier, place it in a muffle furnace for calcination, and cool it down to obtain the pretreated carrier.

[0048] The active component 1 is loaded onto the pretreated carrier: the active component 1 palladium acetate is dissolved in deionized water, the pretreated carrier is placed in the palladium acetate solution, and then allowed to stand at room temperature and dried at a constant temperature in sequence.

[0049] Continue to load the active component 2 onto the carrier: dissolve the active component 2 zinc trifluoromethanesulfonate in deionized water, place the carrier loaded with the active component 1 in the zinc trifluoromethanesulfonate solution, and then sequentially allow to stand at room temperature and dry at a constant temperature.

[0050] The carrier loaded with active components 1 and 2 is calcined to obtain a combined catalyst. The combined catalyst has good stability and is easy to recycle. After multiple uses, it still has high catalytic activity, thereby reducing production costs.

[0051] As an optional example, the concentration of the palladium acetate solution is 20 mg / mL to 40 mg / mL, and particularly preferably 30 mg / mL, and the concentration of the zinc trifluoromethanesulfonate solution is 50 mg / mL to 70 mg / mL, and particularly preferably 60 mg / mL.

[0052] As an optional example, the pretreated support is immersed in a palladium acetate solution at room temperature for 4 to 6 hours, and then dried at a constant temperature of 85° C. to 95° C. for 7 to 9 hours to obtain a first intermediate.

[0053] As an optional example, the carrier loaded with the active component 1 is immersed in a zinc trifluoromethanesulfonate solution at room temperature for 2 h to 4 h, and then dried at a constant temperature of 85° C. to 95° C. for 7 h to 9 h to obtain a second intermediate.

[0054] As an optional example, the carrier includes silicon oxide, the carrier is calcined at a temperature of 400° C., and the calcination time is 3 h to 4 h; the second intermediate is calcined at a temperature of 400° C. to 700° C., and the calcination time is 4 h to 5 h.

[0055] As an optional example, the molar ratio of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate to isooctyl alcohol is 1:(1.3-1.5), and the amount of the catalyst used is 0.3%-0.5% of the mass of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

[0056] As an optional example, in step (1), the value of T1 is 70°C to 90°C, preferably 80°C, the value of Pv1 is -0.02MPa to -0.04MPa, the ultrasonic frequency is 60HZ to 100HZ, preferably 80HZ, and the reaction time is 0.4h to 0.6h.

[0057] As an optional example, in step (2), the value of T2 is 130°C to 140°C, the value of Pv2 is -0.08MPa to -0.1MPa, and the distillation time is 0.3h to 0.6h.

[0058] As an optional example, in step (3), the value of T3 is 20°C to 30°C.

[0059] The method of the present invention has a simple production process, is easy to control the process, has mild reaction conditions, has a short reaction time, saves energy consumption, reduces production costs, and uses a combined catalyst that is easy to recover. The recovered catalyst does not need to be regenerated and can be directly recycled, thereby reducing production costs. Compared with the prior art, it has less pollution and meets environmental protection requirements.

[0060] For better understanding, the present invention is further described below in conjunction with several specific examples, but the preparation process is not limited thereto, and the content of the present invention is not limited thereto.

[0061] Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0062] Example 1

[0063] [Preparation of combined catalyst]

[0064] (1) Calcination activation of the carrier of the composite catalyst: Take the prepared silicon oxide carrier, place it in a muffle furnace and calcine it at 400° C. for 4 hours, then cool it down to obtain the treated carrier.

[0065] (2) Loading the active component 1 onto the pretreated carrier: 3 g of the active component 1 palladium acetate was dissolved in 100 ml of deionized water, the carrier in step (1) was placed therein for immersion, and then allowed to stand at room temperature for 5 h and dried at a constant temperature of 90° C. for 8 h.

[0066] (3) Continue to load the active component 2 onto the carrier: 6 g of the active component 2 zinc trifluoromethanesulfonate was dissolved in 100 ml of deionized water, and the material in step (2) was immersed therein, and then allowed to stand at room temperature for 3 h and dried at a constant temperature of 90° C. for 8 h.

[0067] (4) The material in step (3) was placed in a muffle furnace and calcined at 600° C. for 5 h to finally obtain the combined catalyst used.

[0068] Example 2

[0069] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of the combined catalyst prepared in Example 1 were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0070] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 153.62 g of a transparent water sample, which was the product.

[0071] The 2-ethylhexyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate prepared in this example is colorless and transparent, with a yield of 98.35% and a product purity of 99.42%.

[0072] Example 3

[0073] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 72.85g (0.56mol) of isooctyl alcohol, and 0.585g of the combined catalyst prepared in Example 1 were added. The mixture was purged with nitrogen, the vacuum degree was -0.03MPa, the ultrasonic frequency was 60HZ, the temperature was gradually raised to 70°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0074] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 152.49 g of a transparent water sample, which was the product.

[0075] The 2-octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate prepared in this example is colorless and transparent, with a yield of 97.63% and a product purity of 99.37%.

[0076] Example 4

[0077] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of the combined catalyst prepared in Example 1 were added. The mixture was purged with nitrogen, the vacuum degree was -0.02MPa, the ultrasonic frequency was 100HZ, the temperature was gradually raised to 90°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0078] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 30°C, and the catalyst was removed by filtration to obtain 154.23 g of a transparent water sample, which was the product.

[0079] The 2-ethylhexyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate prepared in this example is colorless and transparent, with a yield of 98.74% and a product purity of 99.57%.

[0080] Example 5

[0081] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid methyl ester, 72.85g (0.56mol) of isooctyl alcohol, and 0.585g of the combined catalyst prepared in Example 1 were added. The mixture was purged with nitrogen, the vacuum degree was -0.03MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0082] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 30°C, and the catalyst was removed by filtration to obtain 152.51 g of a transparent water sample, which was the product.

[0083] The 2-octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate prepared in this example is colorless and transparent, with a yield of 97.64% and a product purity of 99.58%.

[0084] Example 6

[0085] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of a combined catalyst (after 25 repetitions) were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0086] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 153.16 g of a transparent water sample, which was the product.

[0087] The 2-octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate prepared in this example is colorless and transparent, with a yield of 98.06% and a product purity of 99.43%.

[0088] Example 7

[0089] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of a combined catalyst (after 50 repetitions) were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0090] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 154.42 g of a transparent water sample, which was the product.

[0091] The 2-ethylhexyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate prepared in this example is colorless and transparent, with a yield of 98.86% and a product purity of 99.13%.

[0092] Comparative Example 1

[0093] [Preparation of Catalyst]

[0094] (1) Calcination of the catalyst carrier: Take the prepared silica carrier, place it in a muffle furnace and calcine it at 400° C. for 4 hours, and then cool it down to obtain the treated carrier;

[0095] (2) Loading the active component 1 onto the pretreated carrier: 9 g of the active component palladium acetate was dissolved in 100 ml of deionized water, the carrier in step (1) was placed therein for immersion, and then allowed to stand at room temperature for 5 h and dried at a constant temperature of 90° C. for 8 h;

[0096] (3) The material in step (2) was placed in a muffle furnace and calcined at 600° C. for 5 h to finally obtain the catalyst used.

[0097] [Synthesis of Antioxidant 1135]

[0098] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate and 78.14g (0.6mol) of isooctyl alcohol were added, 0.585g of the above-mentioned catalyst was used, nitrogen was purged, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction. After the reaction was completed, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1MPa, and distillation was carried out for 0.5h to evaporate the unreacted isooctyl alcohol. After the reaction was completed, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 153.07g of transparent water sample, which was the product.

[0099] The product obtained in this comparative example is colorless and transparent, wherein the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid isooctyl ester is 86.25%.

[0100] Comparative Example 2

[0101] [Preparation of Catalyst]

[0102] (1) Calcination of the catalyst carrier: Take the prepared silica carrier, place it in a muffle furnace and calcine it at 400° C. for 4 h, then cool it down to obtain the treated carrier.

[0103] (2) Loading the active component 2 onto the pretreated carrier: 9 g of the active component zinc trifluoromethanesulfonate was dissolved in 100 ml of deionized water, the carrier in step (1) was immersed therein, and then allowed to stand at room temperature for 5 h and dried at a constant temperature of 90° C. for 8 h.

[0104] (3) The material in step (2) was placed in a muffle furnace and calcined at 600° C. for 5 h to finally obtain the supported catalyst used.

[0105] [Synthesis of Antioxidant 1135]

[0106] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate and 78.14g (0.6mol) of isooctyl alcohol were added, 0.585g of the above-mentioned catalyst was used, nitrogen was purged, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h, during which methanol was distilled.

[0107] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 154.39 g of a transparent water sample, which was the product.

[0108] The product obtained in this comparative example is colorless and transparent, wherein the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid isooctyl ester is 84.75%.

[0109] Comparative Example 3

[0110] [Preparation of Catalyst]

[0111] (1) Calcination of the catalyst carrier: Take the prepared silica carrier, place it in a muffle furnace and calcine it at 400° C. for 4 hours, and then cool it down to obtain the treated carrier;

[0112] (2) Loading the active component 1 onto the pretreated carrier: 9 g of the active component palladium acetate was dissolved in 100 ml of deionized water, the carrier in step (1) was placed therein for immersion, and then allowed to stand at room temperature for 5 h and dried at a constant temperature of 90° C. for 8 h;

[0113] (3) The material in step (2) was placed in a muffle furnace and calcined at 600° C. for 5 h to finally obtain the catalyst used.

[0114] [Synthesis of Antioxidant 1135]

[0115] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate and 78.14g (0.6mol) of isooctyl alcohol were added, 0.585g of the above-mentioned catalyst was used, nitrogen was purged, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 130°C, and the reaction was carried out for 0.5h, during which methanol was distilled.

[0116] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 152.87 g of a transparent water sample, which was the product.

[0117] The product obtained in this comparative example is light yellow in color, and the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid isooctyl ester is 83.25%.

[0118] Comparative Example 4

[0119] In a 500mL four-necked flask equipped with a mechanical stirrer, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of the combined catalyst prepared in Example 1 were added. The mixture was purged with nitrogen and the vacuum degree was -0.04MPa. The temperature was gradually raised to 80°C and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0120] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 153.55 g of a transparent water sample, which was the product.

[0121] The product obtained in this comparative example is colorless and transparent, wherein the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid isooctyl ester is 83.95%.

[0122] Comparative Example 5

[0123] In a 500mL four-necked flask equipped with a mechanical stirrer, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of the combined catalyst prepared in Example 1 were added. The mixture was purged with nitrogen and the vacuum degree was -0.04MPa. The temperature was gradually raised to 120°C and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0124] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 153.54 g of a transparent water sample, which was the product.

[0125] The product obtained in this comparative example is light yellow in color, and the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester is 83.16%.

[0126] Comparative Example 6

[0127] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid methyl ester, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of the supported catalyst prepared in Example 1 were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 120°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0128] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 154.22 g of a transparent water sample, which was the product.

[0129] The product obtained in this comparative example is light yellow in color, and the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester is 89.67%.

[0130] Comparative Example 7

[0131] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of aluminum isopropoxide were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 80°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0132] After the reaction, the temperature was raised to 140°C, the vacuum degree was adjusted to -0.1 MPa, and distillation was performed for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C, and the catalyst was removed by filtration to obtain 152.37 g of a transparent water sample, which was the product.

[0133] The product obtained in this comparative example is colorless and transparent, wherein the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid isooctyl ester is 66.83%.

[0134] Comparative Example 8

[0135] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of aluminum isopropoxide were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 140°C, and the reaction was carried out for 0.5h. Methanol was distilled during the reaction.

[0136] After the reaction, the vacuum degree was adjusted to -0.1 MPa and distilled for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C and the catalyst was removed by filtration to obtain 153.65 g of a transparent water sample, which was the product.

[0137] The product obtained in this comparative example is light yellow in color, and the purity of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate isooctyl ester is 84.72%.

[0138] Comparative Example 9

[0139] In a 500mL four-necked flask equipped with a mechanical stirrer, an ultrasonicator, a thermometer, a distillation condenser, and a nitrogen inlet, 116.96g (0.4mol) of methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 78.14g (0.6mol) of isooctyl alcohol, and 0.585g of aluminum isopropoxide were added. The mixture was purged with nitrogen, the vacuum degree was -0.04MPa, the ultrasonic frequency was 80HZ, the temperature was gradually raised to 140°C, and the reaction was carried out for 6h. Methanol was distilled during the reaction.

[0140] After the reaction, the vacuum degree was adjusted to -0.1 MPa and distilled for 0.5 h to evaporate the unreacted isooctyl alcohol. After the reaction, the temperature was lowered to 20°C and the catalyst was removed by filtration to obtain 152.43 g of a transparent water sample, which was the product.

[0141] The 2-octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate prepared in this comparative example is dark yellow in color, has a yield of 98.77%, and a product purity of 99.84%.

[0142] Comparative analysis of results

[0143] The reaction conditions of Examples 2-7 and Comparative Examples 1-8, as well as the final product yield and purity results are shown in Table 1. Figure 2-3 shown.

[0144] Table 1

[0145]

[0146]

[0147] Note: The product with a purity greater than 98% is Antioxidant 1135. Therefore, the product with a purity less than 98% does not have the yield parameter of Antioxidant 1135.

[0148] Combination Figure 2-3 From the results of Table 1, it can be seen from the results of Examples 2-7 that the antioxidant 1135 prepared by the method of the present invention has high yield, high purity, good color, and high stability. The color does not change after being stored for 2 years. Moreover, after the catalyst is used multiple times (25 times and 50 times), the yield and purity of the prepared antioxidant 1135 are still very high, and the product color and stability are good, indicating that the prepared combined catalyst has good stability, can be used repeatedly, and still has high catalytic activity after multiple uses.

[0149] It can be seen from the results of Comparative Examples 1-3 that, under other conditions that are the same as those in Example 2, the catalyst used is a single active component, and the purity of the prepared antioxidant 1135 is relatively low, indicating that the catalyst with a single active component cannot form a complex, resulting in the reaction not being able to proceed smoothly at low temperatures even under ultrasonic conditions, and the product has poor purity and stability. The color turns yellow after one month because the catalytic activity of the single active component catalyst is relatively low, and more 3-tert-butyl-4-hydroxy-5-methylphenylpropionic acid methyl ester remains in the reaction system, and 3-tert-butyl-4-hydroxy-5-methylphenylpropionic acid methyl ester turns yellow over time, eventually causing the product to turn yellow as a whole; when high temperature conditions are used, the product directly appears light yellow due to the side reactions and impurities generated by the high temperature.

[0150] From the results of Comparative Examples 4 and 5, it can be seen that under other conditions that are the same as those in Example 2, no ultrasonic device is used to assist the reaction, and the purity of the prepared antioxidant 1135 is relatively low, because in the absence of ultrasound, the breaking of the chemical bonds of the reactants and the formation of new chemical bonds are slow, and the overall catalytic efficiency is low. Even if a complex is formed, the reaction cannot proceed smoothly at low temperatures, and the product purity and stability are poor. The color turns yellow after one month. The reason is also that there is a large amount of 3-tert-butyl-4-hydroxy-5-methylphenylpropionic acid methyl ester remaining in the reaction system, and 3-tert-butyl-4-hydroxy-5-methylphenylpropionic acid methyl ester will turn yellow over time, eventually causing the product to turn yellow as a whole; when high temperature conditions are used, the product directly appears light yellow due to the side reactions and impurities generated by the high temperature.

[0151] From the results of Comparative Example 6, it can be seen that under other conditions that are the same as those of Example 2, the reaction temperature becomes higher, the purity of the prepared antioxidant 1135 is significantly reduced, and the color of the obtained product is light yellow. At the same time, the product stability is also poor. The color becomes darker after being stored for one month. This is because side reactions are likely to occur at high temperatures, resulting in the appearance of impurities, causing the final product to turn yellow. At the same time, at high temperatures, this combined catalyst is unstable, and the complex is likely to react with the generated impurities, deactivating the catalyst, thereby reducing the catalytic activity and reducing the yield and purity of the final product.

[0152] It can be seen from the results of Comparative Example 7 that, under other conditions that are the same as those of Example 2, the reaction catalyst is a traditional catalyst, the reaction cannot proceed smoothly under low temperature conditions, the purity of the prepared antioxidant 1135 is significantly reduced, and the product stability is also poor. The color turns yellow after storage for one month. This is because the catalytic activity of the catalyst is low, and more 3-tert-butyl-4-hydroxy-5-methylphenylpropionic acid methyl ester remains in the reaction system. 3-tert-butyl-4-hydroxy-5-methylphenylpropionic acid methyl ester will turn yellow over time, eventually causing the entire product to turn yellow.

[0153] From the results of Comparative Examples 8 and 9, it can be seen that under the same conditions as Comparative Example 7, by increasing the reaction temperature and reaction time, the yield and purity of the prepared antioxidant 1135 are significantly increased, but the color and stability of the final product are poor. This is because the reaction temperature is too high, side reactions are prone to occur, resulting in the appearance of impurities, causing the final product to turn yellow.

[0154] As can be seen from the above, the method of the present invention, by adopting a combined catalyst and carrying out a catalytic reaction under ultrasonic conditions, has high catalytic efficiency and mild reaction conditions, and the obtained product has high yield and purity, is colorless and transparent, and has good stability, and can still remain colorless and transparent after being placed for 2 years.

[0155] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A method for preparing a liquid hindered phenol antioxidant 1135, characterized in that: The following steps are involved: (1) placing methyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, isooctyl alcohol and a catalyst into an ultrasonic reactor, and under conditions of continuous nitrogen purging and ultrasonication, controlling the vacuum degree in the reactor to be at Pv1 and the reaction temperature to be at T1, reacting, and extracting methanol generated during the reaction; wherein the catalyst is a combined catalyst in which palladium acetate and zinc trifluoromethanesulfonate are loaded on a porous carrier; (2) After the reaction in step (1) is completed, the temperature is adjusted to T2, the vacuum degree is adjusted to Pv2, and distillation is performed to remove unreacted isooctyl alcohol; (3) After step (2), the temperature of the reactants is cooled to T3, the reactants are filtered, and the filtrate is collected to obtain antioxidant 1135.

2. The preparation method according to claim 1, characterized in that: The preparation process of the catalyst comprises the following steps: The carrier is calcined to obtain a pretreated carrier; palladium acetate is dissolved in deionized water to obtain a palladium acetate solution; zinc trifluoromethanesulfonate is dissolved in deionized water to obtain a zinc trifluoromethanesulfonate solution; The pretreated support is immersed in a palladium acetate solution, and after the immersion is completed, it is dried at a constant temperature to obtain a first intermediate; The first intermediate is immersed in a zinc trifluoromethanesulfonate solution, and after the immersion is completed, it is dried at a constant temperature to obtain a second intermediate; The second intermediate is calcined to obtain a combined catalyst.

3. The preparation method according to claim 2, characterized in that: The concentration of the palladium acetate solution is 20 mg / mL to 40 mg / mL, and the concentration of the zinc trifluoromethanesulfonate solution is 50 mg / mL to 70 mg / mL.

4. The preparation method according to claim 2, characterized in that: The pretreated support is immersed in a palladium acetate solution at room temperature for 4 to 6 hours, and then dried at a constant temperature of 85° C. to 95° C. for 7 to 9 hours to obtain a first intermediate.

5. The preparation method according to claim 2, characterized in that: The first intermediate is immersed in a zinc trifluoromethanesulfonate solution at room temperature for 2 h to 4 h, and then dried at a constant temperature of 85° C. to 95° C. for 7 h to 9 h to obtain a second intermediate.

6. The preparation method according to claim 2, characterized in that: The carrier includes silicon oxide, and the carrier is calcined at a temperature of 400° C. for 3 to 4 hours; the second intermediate is calcined at a temperature of 400° C. to 700° C. for 4 to 5 hours.

7. The preparation method according to claim 1, characterized in that: The molar ratio of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid methyl ester to isooctyl alcohol is 1:(1.3-1.5), and the amount of the catalyst used is 0.3%-0.5% of the mass of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid methyl ester.

8. The preparation method according to claim 1, characterized in that: In step (1), the value of T1 is 70°C to 90°C, the value of Pv1 is -0.02MPa to -0.04MPa, the ultrasonic frequency is 60HZ to 100HZ, and the reaction time is 0.4h to 0.6h.

9. The preparation method according to claim 1, characterized in that: In step (2), the value of T2 is 130°C to 140°C, the value of Pv2 is -0.08MPa to -0.1MPa, and the distillation time is 0.3h to 0.6h.

10. The preparation method according to claim 1, characterized in that: In step (3), the value of T3 is 20°C to 30°C.

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