The invention relates to an antioxidant tetra (2, 4-di-tert-butylphenol)-4, 4apos; biphenyl diphosphites and process for the preparation thereof

Abstract

The invention relates to the technical field of antioxidants, and particularly discloses an antioxidant tetra (2, 4-di-tert-butylphenol)-4, 4 '-biphenyl diphosphite and a preparation method thereof. According to the preparation method of the antioxidant tetra (2, 4-di-tert-butylphenol)-4, 4 '-biphenyl diphosphite, a catalyst comprises AlCl3 and NaCl in a molar ratio of (1.4-2.0): 1, the yield of a prepared intermediate product is not lower than 80%, the yield of a final product is not lower than 96.5%, and the purity of the final product is not lower than 98%. The product provided by the invention can effectively prolong the service life of a high polymer material and maintain the original performance of the material, and has good thermal stability and hydrolysis-resistant stability; in addition, the yield of the antioxidant tetra (2, 4-di-tert-butyl phenol)-4, 4 '-biphenyl diphosphite finally prepared by the preparation method is not lower than 96.5%, and the purity is not lower than 98.5%.

Description

Technical Field

[0001] The present application relates to the technical field of antioxidants, and in particular to an antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite and a preparation method thereof. Background Art

[0002] During storage, processing and use, polymer materials such as rubber, plastic, fiber, adhesive, etc. are prone to oxidation reactions with oxygen in the surrounding environment, which damages the internal structure, leads to performance degradation, and gradually loses its use value. Adding antioxidants can effectively extend the service life of polymer materials and maintain the original performance of the materials. It is of great significance to ensure the quality of industrial products, reduce material waste, and improve economic benefits. Antioxidants can eliminate free radicals generated by polymers or promote the decomposition of hydroperoxides, thereby preventing the chain reaction. The antioxidant tetrakis (2,4-di-tert-butylphenyl)-4,4'-biphenyl diphosphite (XNR-58) has good thermal stability and hydrolysis resistance, which can effectively inhibit the volatilization or migration loss of additives in polymer processing and application, and is widely used in polymer materials.

[0003] In order to synthesize the antioxidant tetrakis (2,4-di-tert-butylphenol) -4,4'-biphenyl diphosphite, raw materials such as phenol, biphenyl and phosphorus trichloride are usually mixed, a chemical reaction is carried out under the condition of adding a catalyst, and separation and purification are carried out to finally obtain the product. The synthesis method commonly used in the prior art not only includes directly mixing and heating the reaction raw materials, but also uses a variety of means to separate and purify the reaction products. In addition, there are some improved preparation processes, such as methods for increasing the yield by increasing the stirring speed or changing the reaction temperature. These methods have been mentioned in many documents and patents, and have been applied to a certain extent in industry.

[0004] However, the product yield of the antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite obtained by the above-mentioned synthesis process is low. This problem is particularly obvious in actual industrial production, which limits the large-scale application of XNR-58. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides an antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, comprising the following steps: I. Place PCl 3 、AlCl 3After mixing with NaCl, stir at 50-60°C for 1-1.2h, then heat and stir under reflux, add biphenyl to react, let stand and separate, remove the upper layer of liquid for standby use, and add PCl to the lower layer of liquid 3 Extraction was performed, and the extract was combined with the upper liquid, and PCl3 was removed by atmospheric distillation and then reduced pressure distillation. Then, the upper intermediate product was obtained, in which AlCl 3 The molar ratio of NH4Cl to NaCl is (1.4-2.0):1; II. The intermediate product, 2,4-di-tert-butylphenol and an acid-binding agent are dispersed in toluene and reacted. After the reaction is completed, diatomaceous earth is added and stirred, and the reaction solution is filtered while hot. The temperature is lowered for crystallization, and a solid is obtained by centrifugal filtration. The obtained solid is washed and dried to obtain tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

[0007] Preferably, the AlCl 3 The molar ratio of H2O to NaCl is (1.5-1.9):1.

[0008] Preferably, the AlCl 3 The molar ratio of NaCl is 1.66:1.

[0009] By adopting the above technical solution, the present invention utilizes AlCl 3 As well as NaCl as the catalyst in step I, the two are mixed in the system to first form a complex, which can then play a role in the reaction of biphenyl and PCl 3 The conventional catalytic effect can also reduce the AlCl 3 The possibility of unnecessary complex reaction with a part of the intermediate product generated first is avoided, and the addition of a decomplexing agent (such as phosphorus oxychloride) in the existing preparation method is avoided, thereby achieving the purpose of more convenient catalyst separation, greatly reducing the amount of waste residue generated in the preparation of the intermediate product in the prior art, and further improving the yield of the intermediate product on the basis of shortening the production time and simplifying the operation steps. The yield is not less than 80%, thereby smoothly improving the yield of the final product antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, and the yield is not less than 96.5%.

[0010] At the same time, this application gradually controls AlCl 3 The molar ratio of AlCl to NaCl maximizes the balance between the catalytic effect of the catalyst and the yield of the intermediate product. 3If the dosage is too large, the complexing efficiency between the catalyst and the intermediate product will be increased, which will reduce the yield of the intermediate product. If the dosage of NaCl is too large, the number of active catalytic sites of the catalyst will be greatly reduced, the catalytic effect will be damaged, and the yield of the intermediate product in a fixed time single-pass reaction will also be reduced. Experimental data show that when AlCl 3 When the molar ratio of NaCl is 1.66:1, the yield of the intermediate product can reach the highest, which is 84.4%.

[0011] Preferably, the diatomaceous earth is pretreated before being added to the system, and the specific steps are as follows: The inorganic metal salt and diatomaceous earth in a weight ratio of (8-15):100 are mixed, the temperature is uniformly increased to 1000°C within 3.5 hours for roasting, the temperature is kept for 1.5 hours, and then cooled to room temperature, broken up, and sieved through a 150um sieve to obtain pretreated diatomaceous earth, wherein the inorganic metal salt includes NaNO 3 , NaCl and KCl.

[0012] By adopting the above technical solution, the present application also pre-treats the diatomaceous earth before adding it into the system as a filter aid, using one or more inorganic metal salts and diatomaceous earth mixed in a certain weight ratio, roasted, heat-insulated, cooled, and broken up and passed through a 150um sieve, and the part passing through the sieve is collected to obtain pre-treated diatomaceous earth. The above inorganic metal salt can significantly improve the filter aid effect of diatomaceous earth, thereby further reducing impurities and by-products in the reaction system, thereby greatly improving the purity of the antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

[0013] Preferably, the inorganic metal salt comprises NaNO 3 and KCl.

[0014] Preferably, the NaNO 3 The weight ratio of KCl is (1-1.3):1.

[0015] By adopting the above technical solution, the present application further defines the inorganic metal salt as NaNO 3 and KCl, at this time, the treatment of diatomaceous earth can achieve a better balance between its adsorption capacity and permeability, and has a more excellent improvement effect on the filtration-aid performance of diatomaceous earth compared to single use and other compounding methods. At the same time, the weight ratio of the two is further controlled to be (1-1.3):1. At this time, the filtration-aid effect of diatomaceous earth is very excellent. After being added into the reaction system, the impurities and by-products in the reaction system can be greatly reduced, and the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite reaches 99.12-99.15%.

[0016] Preferably, the weight ratio of the inorganic metal salt to diatomaceous earth is 10:100.

[0017] By adopting the above technical solution, the present application strictly controls the weight ratio of the inorganic metal salt to the diatomaceous earth on the premise of confirming the composition and dosage of the inorganic metal salt, thereby further optimizing the pretreatment effect of the diatomaceous earth. At this time, after the diatomaceous earth is added into the reaction system, the purity of the antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite can be further improved, up to 99.41%.

[0018] Preferably, the acid binding agent comprises diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):1.

[0019] By adopting the above technical solution, the present application uses diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):1 as acid-binding agents, and the two fully exert a synergistic effect, greatly improving the purity of XNR-58.

[0020] In a second aspect, the present application provides an antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite prepared by the above preparation method, with a yield of ≥96.5% and a purity of ≥98.5%.

[0021] In summary, this application has the following beneficial technical effects: 1. The preparation method of the present application avoids the addition of decomplexing agents (phosphorus oxychloride, pyridine, etc.) in the existing preparation method, thereby achieving the purpose of more convenient catalyst separation, greatly reducing the amount of waste residue generated in the preparation of intermediate products in the prior art, not only shortening the production time and simplifying the operation steps, but also further improving the single-pass intermediate product yield, which is not less than 80%, thereby smoothly improving the yield of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, which is not less than 96.5%. At the same time, the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite finally obtained also has a high purity, which can reach more than 98.5%; 2. In the preparation method of the present application, diatomaceous earth is also used for pretreatment with inorganic metal salts, and its adsorption capacity and permeability are improved and are in a better equilibrium state. In addition, the present application controls the components and dosage of the inorganic metal salts. Compared with single use and other compounding methods, the filter aid performance of diatomaceous earth is further improved. After being put into the reaction system, the impurities and by-products in the reaction system can be greatly reduced, so that the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite is significantly improved; 3. The preparation method of the present application utilizes diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):1 as acid-binding agents, which fully exert the synergistic effect and greatly improve the purity of the antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite. DETAILED DESCRIPTION

[0022] Material Source Unless otherwise specified, the raw materials used in this application are all commercially available products, specifically: Diatomaceous earth was purchased from Linjiang Jiahe Kangning Silicon Industry Co., Ltd. 2 Content 85.72%, Al 2 O 3 The content is 4.45%. X-ray diffraction analysis shows that its main mineral composition is amorphous opal, with a small amount of quartz, illite and plagioclase. NaNO 3 , KCl, and NaCl were purchased from Sinopharm Chemical Reagent Co., Ltd.; PCl 3 Purchased from Tianjin Guangfu Fine Chemical Research Institute; AlCl 3 Purchased from Tianjin Damao Reagent Company; Biphenyl was purchased from Shandong Wangtong Chemical Co., Ltd., CAS No. 92-52-4; 2,4-di-tert-butylphenol was purchased from Beijing Jiyi Chemical Co., Ltd., CAS No. 96-76-4; Tert-octylamine was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.; Toluene was purchased from Tianjin Fuyu Fine Chemical Co., Ltd.; Diisopropylethylamine was purchased from Jiangsu Pules Biotechnology Co., Ltd.; Triethylamine was purchased from Jinan Qihang Chemical Technology Co., Ltd.

[0023] The present application is further described in detail below in combination with preparation examples, embodiments and comparative examples.

[0024] Preparation Example 1 The specific steps for pretreatment of diatomaceous earth are as follows: Mix 80g of inorganic metal salt with 1kg of diatomaceous earth, heat it to 1000℃ uniformly within 3.5h for roasting, keep it warm for 1.5h and then cool it to room temperature, break it up, pass it through a 150um sieve and collect the part that passes through the sieve to obtain pretreated diatomaceous earth. The specific components and amounts of the inorganic metal salt are detailed in Table 1.1.

[0025] Table 1.1 Specific components and amounts of inorganic metal salts in Preparation Example 1 Group Specific components and dosage of inorganic metal salts Preparation Example 1.1 <![CDATA[80g of NaNO 3 > Preparation Example 1.2 100g of NaCl Preparation Example 1.3 120 g KCl Preparation Example 1.4 <![CDATA[50 g of NaNO 3 , 50 g of NaCl and 50 g of KCl]]> Preparation Example 1.5 40g NaCl and 100g KCl Preparation Example 1.6 <![CDATA[80 g of NaNO 3 and 40 g of KCl]]> Preparation Example 1.7 <![CDATA[30 g of NaCl and 70 g of NaNO 3 > Preparation Example 2 The pretreatment of diatomite is different from that in Preparation Example 1.6 in that NaNO 3 The dosage of KCl is different, see Table 1.2 for details, and the rest is the same as Preparation Example 1.6.

[0026] Table 1.2 NaNO in Preparation Example 2 3 And the amount of KCl / g Group <![CDATA[NaNO 3 ]]> KCl <![CDATA[NaNO 3 and the weight ratio of KCl]]> Preparation Example 1.6 80 40 2:1 Preparation Example 2.1 67.8 52.2 1.3:1 Preparation Example 2.2 64 56 1.14:1 Preparation Example 2.3 60 60 1:1 Preparation Example 2.4 40 80 1:2 Preparation Example 3 The pretreatment of diatomite differs from that of Preparation Example 1.6 and Preparation Example 2 only in that NaNO 3 The total amount of KCl is different, now 100g, but NaNO 3 The weight ratio of NH4Cl and KCl is the same, as shown in Table 1.3, and the rest is the same as Preparation Example 1.6 and Preparation Example 2.

[0027] Table 1.3 NaNO in Preparation Example 3 3 And the amount of KCl / g Group <![CDATA[NaNO 3 ]]> KCl <![CDATA[NaNO 3 and the weight ratio of KCl]]> Preparation Example 3.1 66.7 33.3 2:1 Preparation Example 3.2 56.5 43.5 1.3:1 Preparation Example 3.3 63.17 36.83 1.14:1 Preparation Example 3.4 50 50 1:1 Preparation Example 3.5 33.3 66.7 1:2 Example 1.1 A method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite comprises the following steps: 1. 4 mol PCl 3 、1.46mol AlCl 3 and 1.04 mol NaCl were mixed and stirred at 60 ° C for 1 h, then heated to 75 ° C, stirred and refluxed, 1 mol biphenyl was added to the system with a constant pressure funnel for reaction, the addition process was controlled at a rate of 5 d / s, and the reaction was carried out for 6.5 h. After the reaction, the temperature was lowered to 50 ° C, and the layers were allowed to stand, the upper layer of liquid was removed and placed in a distillation flask for standby use, and 1 mol PCl was added to the lower layer of liquid 3 The extraction was carried out for 30 min and repeated three times. The extract was then combined with the upper liquid and distilled at atmospheric pressure and then at a pressure of 0.098 MPa and a temperature of 85 °C to remove PCl. 3 , then let it stand for stratification to obtain the intermediate product in the upper layer, the yield of the intermediate product calculated based on biphenyl is 81.2%; II. At a temperature of 90°C, a mixture of 4.1 mol 2,4-di-tert-butylphenol, 37.4 g tert-octylamine and 850 mL toluene was added dropwise to the intermediate product for no more than 30 min. After reacting for 2 h, 12 g diatomaceous earth was added and stirred for 10 min. The reaction solution was filtered while hot, cooled and crystallized until no crystals appeared in the system, centrifuged, and filtered to obtain a solid. The obtained solid was washed 3 times with methanol and then dried at a pressure of -96 kPa and a temperature of 95°C until the system had a constant weight to obtain tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

[0028] Example 1.2 A method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite comprises the following steps: 1. 4 mol PCl 3 、1.67mol AlCl 3 and 0.83 mol NaCl were mixed and stirred at 50 ° C for 1.2 h, then heated to 75 ° C, stirred and refluxed, 1 mol biphenyl was added to the system with a constant pressure funnel for reaction, the addition process was controlled at a rate of 5 d / s, and the reaction was carried out for 6.5 h. After the reaction, the temperature was lowered to 50 ° C, and the layers were allowed to stand, the upper layer of liquid was removed and placed in a distillation flask for standby use, and 1 mol PCl was added to the lower layer of liquid 3 The extraction was carried out for 30 min and repeated three times. The extract was then combined with the upper liquid and distilled at atmospheric pressure and then at a pressure of 0.098 MPa and a temperature of 85 °C to remove PCl. 3 , then let it stand for stratification to obtain the intermediate product in the upper layer, the yield of the intermediate product calculated based on biphenyl is 81.3%; II. At a temperature of 90°C, a mixture of 4.1 mol 2,4-di-tert-butylphenol, 37.4 g tert-octylamine and 850 mL toluene was added dropwise to the intermediate product for no more than 30 min. After reacting for 2 h, 12 g diatomaceous earth was added and stirred for 10 min. The reaction solution was filtered while hot, cooled and crystallized until no crystals appeared in the system, centrifuged, and filtered to obtain a solid. The obtained solid was washed 3 times with methanol and then dried at a pressure of -96 kPa and a temperature of 95°C until the system had a constant weight to obtain tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

[0029] Example 1.3 A method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite comprises the following steps: 1. 4 mol PCl 3 、1.65mol AlCl 3and 0.85 mol NaCl were mixed and stirred at 55 ° C for 1.1 h, then heated to 75 ° C, stirred and refluxed, 1 mol biphenyl was added to the system with a constant pressure funnel for reaction, the addition process was controlled at a rate of 5 d / s, and the reaction was carried out for 6.5 h. After the reaction, the temperature was lowered to 50 ° C, and the layers were allowed to stand, the upper layer of liquid was removed and placed in a distillation flask for standby use, and 1 mol PCl was added to the lower layer of liquid 3 The extraction was carried out for 30 min and repeated three times. The extract was then combined with the upper liquid and distilled at atmospheric pressure and then at a pressure of 0.098 MPa and a temperature of 85 °C to remove PCl. 3 , then let it stand for stratification to obtain the intermediate product in the upper layer, the yield of the intermediate product calculated based on biphenyl is 81.0%; II. At a temperature of 90°C, a mixture of 4.1 mol 2,4-di-tert-butylphenol, 37.4 g tert-octylamine and 850 mL toluene was added dropwise to the intermediate product for no more than 30 min. After reacting for 2 h, 12 g diatomaceous earth was added and stirred for 10 min. The reaction solution was filtered while hot, cooled and crystallized until no crystals appeared in the system, centrifuged, and filtered to obtain a solid. The obtained solid was washed 3 times with methanol and then dried at a pressure of -96 kPa and a temperature of 95°C until the system had a constant weight to obtain tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

[0030] Example 2 A method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, which is different from that in Example 1.1, in step I, AlCl 3 The dosage is different from that of NaCl, as shown in Table 1.4, and the rest is the same as Example 1.1.

[0031] Table 1.4 AlCl in Example 2 3 Dosage and ratio of NaCl Group <![CDATA[AlCl 3 ]]> NaCl <![CDATA[AlCl 3 and NaCl molar ratio]]> Example 1.1 1.46 1.04 1.4:1 Example 2.1 1.5 1.0 1.5:1 Example 2.2 1.52 0.98 1.55:1 Example 2.3 1.56 0.94 1.66:1 Example 2.4 1.61 0.89 1.8:1 Example 2.5 1.64 0.86 1.9:1 Example 2.6 1.67 0.83 2.0:1 Examples 3.1-3.16 A method for preparing an antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, which is different from Example 1.1 in that the diatomaceous earth in step II is replaced by the pretreated diatomaceous earth prepared in Preparation Examples 1.1-3.5, and the rest is the same as Example 1.1.

[0032] Example 4 A method for preparing an antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, which is different from Example 1.1 in that in step II, the components and amounts of the acid-binding agent are different, as shown in Table 1.5, and the rest are the same as Example 1.1.

[0033] Table 1.5 Components and dosage of the acid binding agent of Example 4 Group Components and dosage of acid binding agent Example 1.1 Tert-octylamine 37.4g Example 4.1 Diisopropylethylamine 37.4g Example 4.2 Triethylamine 37.4g Example 4.3 Diisopropylethylamine 18.7 g and triethylamine 18.7 g Example 4.4 Diisopropylethylamine 19.4g and triethylamine 18g Example 4.5 Diisopropylethylamine 20.4g and triethylamine 17g Example 4.6 Diisopropylethylamine 19.4g and tert-octylamine 18g Example 4.7 19.4 g tert-octylamine and 18 g triethylamine Comparative Example 1 Refer to the method of Example 5 in Patent No. CN104860990.

[0034] Comparative Example 2 The difference from Example 1.1 is that in step I, AlCl 3 The dosage is different from that of NaCl, see Table 1.6 for details, and the rest is the same as Example 1.1.

[0035] Table 1.4 AlCl of Comparative Example 2 3 Dosage and ratio of NaCl Group <![CDATA[AlCl 3 ]]> NaCl <![CDATA[AlCl 3 and NaCl molar ratio]]> Example 1.1 1.46 1.04 1.4:1 Comparative Example 2.1 1.25 1.25 1:1 Comparative Example 2.2 1.875 0.625 3:1 Performance Testing 1. Intermediate product yield: Calculate the molar number of the intermediate product by the effective substance content and express the yield in terms of biphenyl, and record it in Table 2; 2. Purity: The effective substance content of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite was determined by ultraviolet absorption spectroscopy and internal standard method, and the purity was calculated and recorded in Table 2; 3. Yield: The molar number of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite was calculated by the effective substance content, and the yield was expressed as biphenyl and recorded in Table 2.

[0036] Table 2 Antioxidant XNP-58 test results Data Analysis: As can be seen from Table 2, the yield of the intermediate product of Examples 1.1-1.3 reached 81.0-81.3%, the yield of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite reached 96.5-96.6%, and the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite reached 98.57-98.59%, proving that the present application uses AlCl 3 As a catalyst in step I, NaCl can not only play a conventional catalytic effect, but also reduce the AlCl 3The unnecessary complexation reaction with the first generated intermediate product avoids the addition of a decomplexing agent (phosphorus oxychloride, pyridine, etc.) in the existing preparation method, thereby achieving the purpose of more convenient catalyst separation, greatly reducing the amount of waste residue generated in the preparation of the intermediate product in the prior art, and improving the single-pass intermediate product yield, thereby smoothly improving the yield of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite; In Example 2, the present application further optimizes AlCl 3 and NaCl ratio, wherein the intermediate product yield and antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite yield of Examples 2.1-2.5 are significantly higher than those of Examples 2.6 and 1.1. In Examples 2.1-2.5, the intermediate product yield and antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite yield of Example 2.3 are as high as 84.4% and 98.3%, respectively, proving that the present invention can effectively reduce the production cost of the intermediate product by adjusting the AlCl 3 and the ratio of NaCl, maximally balancing the catalytic effect of the catalyst and the yield of the intermediate product; In Example 3, the present application optimized diatomite and pretreated it with different inorganic metal salts. The results showed that the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite in Example 3 was higher than that in Example 1.1, proving that the pretreated diatomite in the present application did have a better filtering effect than ordinary diatomite, and greatly reduced the impurities and by-products in the reaction system, thereby improving the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite; In Examples 3.1-3.7, the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite in Example 3.6 is significantly higher than that in other examples, proving that the present invention uses NaNO 3 The compounding with KCl as an inorganic metal salt for pre-treating diatomite can achieve a better balance between its adsorption capacity and permeability. Compared with single use and other compounding methods, it has a more excellent improvement effect on the filter-aiding performance of diatomite, which further improves the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite; In Examples 3.8-3.11, the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite in Examples 3.8-3.10 is much higher than that in Examples 3.11 and 3.6, which proves that the present invention further controls the NaNO 3The ratio of diatomite and KCl can achieve a better balance between the adsorption capacity and permeability of diatoms. At this time, the diatomite has an excellent filtering effect. After being added into the reaction system, it can greatly reduce the impurities and by-products in the reaction system, so that the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite reaches 99.12-99.15%; Embodiments 3.12-3.16 are improvements made in Embodiments 3.6 and 3.8-3.11. On the premise of confirming the composition and dosage of the inorganic metal salt, the weight ratio of the inorganic metal salt to the diatomaceous earth is strictly controlled, thereby further optimizing the pretreatment effect of the diatomaceous earth. At this time, after the diatomaceous earth is added into the reaction system, the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite can be further improved to 99.20-99.41%; In Example 4, the present application optimizes the acid-binding agent, wherein the purity of the antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite in Examples 4.3-4.5 is significantly higher than that in other examples, proving that the present application uses diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):1 as acid-binding agents, which enables the two to fully exert a good synergistic effect, and greatly improves the purity of the antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite to 98.89-98.92%; The yield of the intermediate product in Comparative Example 1 is only 72.6%, the yield of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite is only 92.5%, and the purity of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite is 96.58%, which proves that the present invention can obtain the intermediate product of Comparative Example 1 by using AlCl 3 As a catalyst in step I, NaCl can not only play a conventional catalytic effect, but also reduce the AlCl 3 The unnecessary complexation reaction with the first generated intermediate product avoids the addition of a decomplexing agent (phosphorus oxychloride, pyridine, etc.) in the existing preparation method, thereby achieving the purpose of more convenient catalyst separation, greatly reducing the amount of waste residue generated in the preparation of the intermediate product in the prior art, and improving the single-pass intermediate product yield, thereby smoothly improving the yield of the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite; The yield of the intermediate product and the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite in Comparative Examples 2.1-2.2 are much lower than those in Example 1.1, which proves that the present invention can effectively reduce the oxidation of the intermediate product and the antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite by adjusting the AlCl 3 The ratio of NaCl indeed balances the catalytic effect of the catalyst and the yield of the intermediate product, so that the yield of the final antioxidant tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite is significantly improved.

[0037] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, characterized in that: The following steps are involved: Mix PCl3, AlCl3 and NaCl and stir at 50-60°C for 1-1.2h, then heat and stir under reflux, add biphenyl to react, let stand for stratification after reaction, remove the upper layer of liquid for standby use, add PCl3 to the lower layer of liquid for extraction, combine the extract with the upper layer of liquid, first distill at normal pressure, then distill at reduced pressure to remove PCl3, then let stand for stratification to obtain the upper intermediate product, wherein the molar ratio of AlCl3 to NaCl is (1.4-2.0):1; The intermediate product, 2,4-di-tert-butylphenol and an acid-binding agent are dispersed in toluene and reacted. After the reaction is completed, diatomaceous earth is added and stirred, and the reaction solution is filtered while hot. The temperature is lowered for crystallization, and a solid is obtained by centrifugal filtration. The obtained solid is washed and dried to obtain tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

2. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 1, characterized in that: The molar ratio of AlCl3 to NaCl is (1.5-1.9):

1.

3. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 2, characterized in that: The molar ratio of AlCl3 to NaCl is 1.66:

1.

4. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 1, characterized in that: The diatomaceous earth is also pretreated before being added to the system, and the specific steps are as follows: An inorganic metal salt with a weight ratio of (8-15):100 is mixed with diatomaceous earth, roasted, cooled, broken up, and sieved through a 150um sieve to obtain pretreated diatomaceous earth, wherein the inorganic metal salt includes one or more of NaNO3, NaCl and KCl.

5. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 4, characterized in that: The inorganic metal salts include NaNO3 and KCl.

6. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 5, characterized in that: The weight ratio of NaNO3 and KCl is (1-1.3):

1.

7. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 5 or 6, characterized in that: The weight ratio of the inorganic metal salt to diatomaceous earth is 10:

100.

8. The method for preparing an antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite according to claim 1, characterized in that: The acid binding agent comprises diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):

1.

9. An antioxidant tetrakis (2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The yield is ≥96.5% and the purity is ≥98.5%.

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