Antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite and preparation method therefor

Abstract

The present application 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 therefor. In the preparation method for the antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite, the catalyst comprises AlCl3 and NaCl in a molar ratio of (1.4–2.0):1, an obtained intermediate product has a yield of not less than 80%, and the final product has a yield of not less than 96.5% and a purity not less than 98%. The product of the present application can effectively extend the service life of polymeric materials and preserve the original properties of the materials, exhibiting good thermal stability and hydrolytic stability. In addition, the preparation method of the present application produces the antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite with a final yield of not less than 96.5% and a purity of not less than 98.5%.

Description

An antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite and a preparation method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of antioxidants, and in particular to an antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite and a preparation method thereof. BACKGROUND

[0002] During storage, processing and use, high molecular materials such as rubber, plastic, fiber, adhesive and the like are prone to oxidation reaction with oxygen in the surrounding environment, which destroys the internal structure and leads to performance degradation and gradual loss of use value. The addition of antioxidants can effectively prolong the service life of high molecular materials and maintain the original performance of the materials, which is of great significance to the quality of industrial products, the reduction of material waste and the improvement of economic benefits. Antioxidants can eliminate free radicals generated by polymers or promote the decomposition of hydroperoxide, thereby preventing chain reactions. Antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite (XNR-58) has good thermal stability and hydrolysis resistance, and can effectively inhibit the volatilization or migration loss of additives during polymer processing and application, and is widely used in high molecular materials.

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

[0004] However, the product yield of antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite prepared by the above synthesis process is low, which is particularly obvious in actual industrial production, and limits the large-scale application of XNR-58. SUMMARY

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

[0006] In a first aspect, the application provides a preparation method of antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite, comprising the following steps: I. mixing PCl3, AlCl3 and NaCl, stirring at a temperature of 50-60°C for 1-1.2h, then heating and stirring to reflux, adding biphenyl for reaction, after the reaction is completed, standing and separating into layers, removing the upper liquid for use, and adding PCl3 to the lower liquid for extraction, combining the extraction liquid with the upper liquid, first normal-pressure distillation, then reduced-pressure distillation to remove PCl3, then standing and separating into layers to obtain the intermediate product in the upper layer, wherein the molar ratio of AlCl3 to NaCl is (1.4-2.0):1; II. dispersing the intermediate product, 2,4-di-tert-butylphenol and an acid-binding agent in toluene and performing reaction, after the reaction is completed, adding diatomite, stirring and filtering the reaction liquid while hot, cooling and crystallizing, centrifugal filtration to obtain a solid, washing and drying the obtained solid to obtain tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite.

[0007] Preferably, the molar ratio of AlCl3 to NaCl is (1.5-1.9):1.

[0008] Preferably, the molar ratio of AlCl3 to NaCl is 1.66:1.

[0009] By adopting the above technical solution, the application uses AlCl3 and NaCl as the catalyst in step I, and the two are blended and reacted in the system to first form a complex, which not only has a conventional catalytic effect on biphenyl and PCl3, but also reduces the possibility of unnecessary complexation reaction between AlCl3 and a part of the intermediate product generated in advance in the reaction, avoids the addition of a decomplexing agent (such as phosphorus oxychloride) in the existing preparation method, and thus achieves the purpose of more convenient separation of the catalyst, greatly reduces the amount of waste residue generated in the preparation of the intermediate product in the prior art, further improves the yield of the intermediate product on the basis of shortening the production time and simplifying the operation steps, and the yield is not less than 80%, which successfully improves the yield of the final product antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite, and the yield is not less than 96.5%.

[0010] Meanwhile, the application gradually controls the molar ratio of AlCl3 and NaCl, maximizes the balance of the catalytic effect of the catalyst and the yield of the intermediate product, if the amount of AlCl3 is too large, the complexing effect of the catalyst and the intermediate product will be improved, and the yield of the intermediate product will be reduced; if the amount of NaCl is too large, the number of active catalytic sites of the catalyst will decrease significantly, the catalytic effect will be damaged, and the yield of the intermediate product in the single-pass reaction of the fixed time will also be reduced. Experimental data shows that when the molar ratio of AlCl3 and NaCl is 1.66:1, the yield of the intermediate product can reach the highest, which is 84.4%.

[0011] Preferably, the diatomite is also pretreated before being added to the system, and the specific steps are as follows: inorganic metal salts with a weight ratio of (8-15):100 are mixed with diatomite, uniformly heated to 1000℃ within 3.5h for calcination, cooled to room temperature after holding for 1.5h, dispersed, and then sieved through a 150um sieve to obtain pretreated diatomite, and the inorganic metal salts include one or more of NaNO3, NaCl and KCl.

[0012] By adopting the above technical solution, the application further pretreats the diatomite before adding it to the system, mixes one or more inorganic metal salts with the diatomite according to a certain weight ratio, calcines, holds, cools, disperses, and then sieves through a 150um sieve, collects the part passing through the sieve, and obtains pretreated diatomite, and the above inorganic metal salts can significantly improve the filtering aid effect of the diatomite, thereby further reducing impurities and byproducts in the reaction system, and further improving the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite.

[0013] Preferably, the inorganic metal salts include NaNO3 and KCl.

[0014] Preferably, the weight ratio of NaNO3 and KCl is (1-1.3):1.

[0015] By adopting the above technical solution, the application further limits the inorganic metal salts to be NaNO3 and KCl, which can achieve a better balance between the adsorption capacity and permeability of the diatomite, and has a more excellent improvement effect on the filtering aid performance of the diatomite compared to single use and other compounding methods, and further controls the weight ratio of the two to be (1-1.3):1, at which the filtering aid effect of the diatomite is very excellent, can greatly reduce impurities and byproducts in the reaction system after being put into the reaction system, and makes the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite reach 99.12-99.15%.

[0016] Preferably, the weight ratio of the inorganic metal salts to the diatomite is 10:100.

[0017] By adopting the technical scheme, the weight ratio of the inorganic metal salt and diatomite is strictly controlled on the premise of confirming the composition and dosage of the inorganic metal salt, so that the pretreatment effect of the diatomite is further optimized, and the purity of the antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite can be further improved after the diatomite is put into the reaction system, and the purity can be as high as 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 technical scheme, diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):1 are used as the acid-binding agent, and the two fully play a synergistic effect, greatly improving the purity of XNR-58.

[0020] In the second aspect, the application provides the antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite prepared by the above preparation method, the yield of which is ≥96.5%, and the purity of which is ≥98.5%.

[0021] In summary, the application has the following beneficial technical effects: 1. The preparation method of the application avoids the addition of a complexing agent (phosphorus oxychloride, pyridine, etc.) in the existing preparation method, thereby achieving the purpose of more convenient separation of the catalyst, greatly reducing the amount of waste generated in the preparation of the intermediate product 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 successfully improving the yield of the antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite, which is not less than 96.5%, and the finally prepared antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite also has a high purity, which can be more than 98.5%; 2. In the preparation method of the application, diatomite is pretreated with an inorganic metal salt, and the adsorption capacity and permeability of the diatomite are improved and are in a relatively optimal balance, and the composition and dosage of the inorganic metal salt are controlled, which further improves the filter aid performance of the diatomite compared with single use and other compounding methods, and can greatly reduce impurities and by-products in the reaction system after being put into the reaction system, thereby significantly improving the purity of the antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite; 3. In the preparation method of the application, diisopropylethylamine and triethylamine in a weight ratio of (1-1.2):1 are used as the acid-binding agent, and the two fully play a synergistic effect, greatly improving the purity of the antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-diphenyl diphosphite. DETAILED DESCRIPTION

[0022] The raw materials used in the present application are commercially available products, except for special instructions. Specifically, diatomite was purchased from Jingjiang Jihe Kangning Silicon Industry Co., Ltd., with a SiO2 content of 85.72% and an Al2O3 content of 4.45%. X-ray diffraction analysis showed that the main mineral composition was amorphous opal, with a small amount of quartz, illite, and plagioclase. NaNO3, KCl, and NaCl were purchased from the National Pharmaceutical Group Chemical Reagent Co., Ltd. PCl3 was purchased from the Tianjin Guangfu Fine Chemical Institute. AlCl3 was purchased from Tianjin Damao Reagent Co., Ltd. Biphenyl was purchased from Shandong Wantong Chemical Co., Ltd., with a CAS number of 92-52-4. 2,4-Di-tert-butyl phenol was purchased from Beijing Jiyi Chemical Co., Ltd., with a CAS number of 96-76-4. Tertiary 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 Puleisi Biological Technology Co., Ltd. Triethylamine was purchased from Jinan Qihang Chemical Technology Co., Ltd.

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

[0024] Preparation Example 1: Pretreatment of diatomite, the specific steps are as follows: 80g of inorganic metal salt was mixed with 1kg of diatomite, and the temperature was uniformly raised to 1000℃ within 3.5h for calcination. After 1.5h of heat preservation, it was cooled to room temperature, broken up, and passed through a 150um sieve. The part passing through the sieve was collected to obtain pretreated diatomite. The specific components and amounts of inorganic metal salts are shown in Table 1.1.

[0025] Table 1.1 Specific components and amounts of inorganic metal salts in preparation example 1 Preparation Example 2: Pretreatment of diatomite, which is different from preparation example 1.6 only in the amount of NaNO3 and KCl, which is shown in Table 1.2. The rest is the same as preparation example 1.6.

[0026] Table 1.2 Amount of NaNO3 and KCl in preparation example 2 / g Preparation Example 3: Pretreatment of diatomite, which is different from preparation example 1.6 and preparation example 2 only in the total amount of NaNO3 and KCl, which is now 100g, but the weight ratio of NaNO3 and KCl is the same. The specific details are shown in Table 1.3. The rest is the same as preparation example 1.6 and preparation example 2.

[0027] Table 1.3 Amount of NaNO3 and KCl in preparation example 3 / g Example 1.1 A method for preparing antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'- diphenyl diphosphite, comprising the following steps: I. mixing 4 mol of PCl3, 1.46 mol of AlCl3, and 1.04 mol of NaCl, stirring at 60°C for 1 h, then increasing the temperature to 75°C, stirring to reflux, adding 1 mol of diphenyl to the system using a constant pressure funnel, controlling the speed of addition at 5 d / s, reacting for 6.5 h, after the reaction is complete, cooling to 50°C, allowing the layers to separate, removing the upper liquid to a distillation flask for use, adding 1 mol of PCl3 to the lower liquid for extraction for 30 min, repeating the extraction operation 3 times, then combining the extraction liquid with the upper liquid, first distilling under normal pressure, then distilling under reduced pressure at a pressure of 0.098 MPa and a temperature of 85°C to remove PCl3, then allowing the layers to separate, obtaining the intermediate product in the upper layer, the yield of the intermediate product being 81.2% based on diphenyl; II. adding a mixture of 4.1 mol of 2,4-di-tert-butylphenol, 37.4 g of tert-octylamine, and 850 mL of toluene dropwise to the intermediate product at a temperature of 90°C, the dropwise addition taking no more than 30 min, adding 12 g of diatomite after reacting for 2 h, stirring for 10 min, filtering the reaction liquid while hot, cooling to crystallize until no crystals appear in the system, centrifuging, filtering, obtaining a solid, washing the obtained solid with methanol 3 times, then drying under a pressure of -96 kPa and a temperature of 95°C until the system reaches a constant weight, obtaining tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite.

[0028] Example 1.2 A method for preparing an antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite, comprising the following steps: I. mixing 4 mol of PCl3, 1.67 mol of AlCl3, and 0.83 mol of NaCl, stirring at 50 °C for 1.2 h, then warming to 75 °C, stirring to reflux, adding 1 mol of diphenyl to the system using a constant pressure funnel, controlling the speed of addition to be 5 d / s, reacting for 6.5 h, after the reaction is complete, cooling to 50 °C, allowing the layers to separate, removing the upper liquid to a distillation flask for use, adding 1 mol of PCl3 to the lower liquid for extraction for 30 min, repeating the extraction operation 3 times, then combining the extraction liquid with the upper liquid, first distilling under normal pressure, then distilling under reduced pressure at a pressure of 0.098 MPa and a temperature of 85 °C to remove PCl3, then allowing the layers to separate, obtaining the intermediate product in the upper layer, the yield of the intermediate product being 81.3% based on diphenyl; II. adding a mixture of 4.1 mol of 2,4-di-tert-butylphenol, 37.4 g of t-octylamine, and 850 mL of toluene dropwise to the intermediate product at a temperature of 90 °C, the dropwise addition taking no more than 30 min, adding 12 g of diatomite after reacting for 2 h, stirring for 10 min, filtering the reaction liquid while hot, cooling to crystallize until no crystals appear in the system, centrifuging, filtering, obtaining a solid, washing the obtained solid with methanol 3 times, then drying under a pressure of -96 kPa and a temperature of 95 °C until the system reaches a constant weight, obtaining tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyl diphosphite.

[0029] Example 1.3 A method for preparing an antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyldiphosphite, comprising the following steps: I. mixing 4 mol of PCl3, 1.65 mol of AlCl3, and 0.85 mol of NaCl, stirring at 55°C for 1.1 h, then increasing the temperature to 75°C, stirring to reflux, adding 1 mol of diphenyl to the system through a constant pressure funnel, controlling the speed of addition to be 5 d / s, reacting for 6.5 h, after the reaction is completed, decreasing the temperature to 50°C, allowing the system to stand and separate into layers, removing the upper liquid to a distillation flask, and adding 1 mol of PCl3 to the lower liquid for extraction for 30 min, repeating the extraction operation 3 times, then combining the extraction liquid with the upper liquid, first distilling under normal pressure, then distilling under reduced pressure at a pressure of 0.098 MPa and a temperature of 85°C to remove PCl3, then allowing the system to stand and separate into layers, obtaining the intermediate product in the upper layer, and the yield of the intermediate product is 81.0% based on the amount of diphenyl; II. adding a mixture of 4.1 mol of 2,4-di-tert-butylphenol, 37.4 g of tert-octylamine, and 850 mL of toluene dropwise to the intermediate product at a temperature of 90°C, the dropwise addition time is not more than 30 min, after reacting for 2 h, adding 12 g of diatomite and stirring for 10 min, filtering the reaction liquid while it is hot, decreasing the temperature to crystallize until no crystals appear in the system, centrifuging, filtering, obtaining a solid, washing the obtained solid with methanol 3 times, and then drying the solid under a pressure of -96 kPa and a temperature of 95°C until the system reaches a constant weight, obtaining tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyldiphosphite.

[0030] Example 2 A method for preparing an antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyldiphosphite, which is different from Example 1.1 in that, in step I, the amounts of AlCl3 and NaCl are different, for details, see Table 1.4, and the rest is the same as Example 1.1.

[0031] Table 1.4 Amounts and proportions of AlCl3 and NaCl in Example 2 Examples 3.1-3.16 A method for preparing an antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyldiphosphite, which is different from Example 1.1 in that, in step II, the diatomite is replaced by pretreated diatomite 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 tetra(2,4-di-tert-butylphenyl)-4,4'-diphenyldiphosphite, which is different from Example 1.1 in that, in step II, the components and amounts of the acid-binding agent are different, for details, see Table 1.5, and the rest is the same as Example 1.1.

[0033] Table 1.5 Components and amounts of the acid-binding agent in Example 4 Comparative Example 1 The method of Example 5 in patent No. CN104860990 was referred to.

[0034] Comparative Example 2 The difference between Example 1.1 and Comparative Example 2 is that the amount of AlCl3 and NaCl used in Step I is different, see Table 1.6 for details, and the rest is the same as Example 1.1.

[0035] Table 1.4 Amount and ratio of AlCl3 and NaCl in Comparative Example 2 Performance detection 1. Intermediate product yield: The number of moles of intermediate product was calculated by the active substance content, and the yield was expressed by biphenyl, which was recorded in Table 2; 2. Purity: The active substance content of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite was determined by ultraviolet absorption spectrum and internal standard method, the purity was calculated and recorded in Table 2; 3. Yield: The number of moles of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite was calculated by the active substance content, and the yield was expressed by biphenyl, which was recorded in Table 2.

[0036] Table 2 Detection results of antioxidant XNP-58 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 antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite reached 96.5-96.6%, and the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite reached 98.57-98.59%, proving that by using AlCl3 and NaCl as catalysts in step I, the present application not only has a conventional catalytic effect, but also reduces unnecessary complexation of AlCl3 with the first generated intermediate product in the reaction, avoids the addition of a decomplexing agent (phosphorus oxychloride, pyridine, etc.) in the existing preparation method, thereby achieving the purpose of more convenient separation of the catalyst, greatly reducing the amount of waste residue generated in the preparation of the intermediate product in the prior art, improving the single-pass intermediate product yield, and thereby smoothly improving the yield of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite; In Example 2, the present application further optimizes the ratio of AlCl3 and NaCl, wherein the yield of the intermediate product and the yield of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite of Examples 2.1-2.5 are significantly higher than those of Example 2.6 and Example 1.1. In Examples 2.1-2.5, the yield of the intermediate product and the yield of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite of Example 2.3 are as high as 84.4% and 98.3%, respectively, proving that by adjusting the ratio of AlCl3 and NaCl, the present application maximizes the balance between the catalytic effect of the catalyst and the yield of the intermediate product; In Example 3, the present application optimizes diatomaceous earth by pretreating it with different inorganic metal salts. The results show that the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite of Example 3 is higher than that of Example 1.1, proving that the pretreated diatomaceous earth of the present application indeed has a better filtering aid effect than ordinary diatomaceous earth, greatly reducing the content of impurities and by-products in the reaction system, thereby improving the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite; In Examples 3.1-3.7, the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite of Example 3.6 is significantly higher than that of other examples, proving that by selecting NaNO3 and KCl for compounding as inorganic metal salts to pretreat diatomaceous earth, the present application can achieve a better balance between the adsorption capacity and permeability of diatomaceous earth, and has a more excellent improvement effect on the filtering aid performance of diatomaceous earth compared to single use and other compounding methods, thereby further improving the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite; In Examples 3.8-3.11, the purity of antioxidant tetra(2,4-di-tert-butyl phenol)-4,4'-biphenyl diphosphite of Example 3.8-3.The purity of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite of Example 10 is much higher than that of Example 3.11 and Example 3.6, which proves that by further controlling the ratio of NaNO3 and KCl, the present application can achieve a better balance between the adsorption capacity and permeability of diatomite, and at this time, the diatomite has very excellent filtration aid effect, and after being put into the reaction system, it can greatly reduce the impurities and by-products in the reaction system, so that the purity of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite reaches 99.12-99.15%; Examples 3.12-3.16 are improvements on the basis of Example 3.6 and Examples 3.8-3.11, and under the premise of confirming the composition and amount of inorganic metal salt, the weight ratio of inorganic metal salt and diatomite is strictly controlled, so as to further optimize the pretreatment effect of diatomite, and at this time, after the diatomite is put into the reaction system, the purity of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite can be further improved, which can reach 99.20-99.41%; in Example 4, the deacidifying agent is optimized, and the purity of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite of Examples 4.3-4.5 is obviously higher than that of other examples, which proves that by using diisopropylethylamine and triethylamine with a weight ratio of (1-1.2):1 as the deacidifying agent, the two can fully play a good synergistic effect, and the purity of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite can be greatly improved to 98.89-98.92%; the intermediate product yield of Comparative Example 1 is only 72.6%, the yield of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite is only 92.5%, and the purity of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite is 96.58%, which proves that by using AlCl3 and NaCl as the catalyst in step I, the present application not only has the conventional catalytic effect, but also can reduce the unnecessary complexation reaction between AlCl3 and the intermediate product generated first, avoids the addition of a decomplexing agent (phosphorus oxychloride, pyridine, etc.) in the existing preparation method, so as to achieve the purpose of more convenient separation of the catalyst, greatly reduces the generation amount of waste slag in the preparation of the intermediate product in the prior art, and improves the single-pass intermediate product yield, so as to successfully improve the yield of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite; the intermediate product yield and the yield of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite of Comparative Examples 2.1-2.2 are much lower than those of Example 1.1, which proves that by adjusting the ratio of AlCl3 and NaCl, the present application indeed balances the catalytic effect of the catalyst and the yield of the intermediate product, so that the yield of antioxidant tetra(2,4-di-tert-butylphenol)-4,4'-biphenylene diphosphite obtained finally is significantly improved.

[0037] The embodiments of the present application are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, and thus: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A process for the preparation of the antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, characterized in that, The method comprises the following steps: mixing PCl3, AlCl3 and NaCl, stirring at a temperature of 50-60℃ for 1-1.2h, then heating and stirring to reflux, adding biphenyl to react, after the reaction, standing and separating the layers, removing the upper liquid for use, and adding PCl3 to the lower liquid to extract, combining the extract with the upper liquid, first normal-pressure distillation, then reduced-pressure distillation to remove PCl3, then standing and separating the layers to obtain the intermediate product in the upper layer, wherein the molar ratio of AlCl3 to NaCl is (1.4-2.0):1; dispersing the intermediate product, 2,4-di-tert-butylphenol and acid-binding agent in toluene to react, after the reaction, adding diatomite to stir and filter the reaction liquid while hot, cooling and crystallizing, centrifugal filtration to obtain solid, washing and drying the obtained solid to obtain tetrakis(2,4-di-tert-butylphenol)-4,4'-biphenyl diphosphite.

2. A process for the preparation of antioxidant Tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite according to claim 1, characterized in that, The molar ratio of AlCl3 to NaCl is (1.5-1.9):

1.

3. A process for the preparation of antioxidant Tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite according to claim 2, characterized in that, The molar ratio of AlCl3 to NaCl is 1.66:

1.

4. A process for the preparation of antioxidant Tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite according to claim 1, characterized in that, The diatomite is also pretreated before being added to the system, and the specific steps are as follows: mixing inorganic metal salt with a weight ratio of (8-15):100 and diatomite, calcining, cooling, breaking up, and passing through a 150um sieve to obtain pretreated diatomite, wherein the inorganic metal salt comprises one or more of NaNO3, NaCl and KCl.

5. A process for the preparation of antioxidant Tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite according to claim 4, characterized in that, The inorganic metal salt comprises NaNO3 and KCl.

6. A process for the preparation of antioxidant Tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite according to claim 5, characterized in that, The weight ratio of NaNO3 to KCl is (1-1.3):

1.

7. A process for the preparation of the antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite according to claim 5 or 6, characterized in that, The weight ratio of the inorganic metal salt to diatomite is 10:

100.

8. A process for the preparation of antioxidant Tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite according to claim 1, characterized in that, The acid-binding agent comprises diisopropylethylamine and triethylamine with a weight ratio of (1-1.2):

1.

9. The antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite prepared by the process of any one of claims 1 to 8, characterized in that, The yield thereof is ≥96.5%, and the purity thereof is ≥98.5%.

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