Synthesis process of non-phenolic phosphite antioxidant TTDP

Abstract

The application relates to the field of antioxidant synthesis, and particularly discloses a synthesis process of a phenol-free phosphite antioxidant TTDP. The synthesis process of the phenol-free phosphite antioxidant TTDP takes trialkyl phosphite and isomeric tridecanol as raw materials, and obtains the product through distillation and purification under the catalysis of alkoxy aluminum. The synthesis process of the phenol-free phosphite antioxidant TTDP has the advantages of high catalytic efficiency, significant improvement of effective content, fast reaction process and great improvement of the synthesis efficiency of the antioxidant TTDP, since alkoxy aluminum is used as a catalyst to catalyze the reaction of trialkyl phosphite and isomeric tridecanol.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of antioxidant synthesis, more particularly, it relates to a synthesis process of a phenol-free phosphite antioxidant TTDP. BACKGROUND

[0002] During the processing or use of polymer materials, due to the factors such as light, heat, oxygen, etc., oxidative degradation and free radicals and hydroperoxides are generated, which leads to the decline of the physical properties of the polymer materials. In order to solve the above problems, phosphite antioxidants are generally added to the polymer materials, which decompose the hydroperoxides formed by the oxidation of the polymer materials, preventing or delaying the thermal oxidative degradation of the polymer materials.

[0003] Phosphite antioxidants are mainly divided into solid and liquid two categories, typical liquid antioxidants include decyl phosphite, dodecyl phosphite, tridecyl phosphite, etc. Tridecyl phosphite is also called tris-isotridecyl phosphite (hereinafter referred to as TTDP). At present, the synthesis route of TTDP is generally divided into two kinds: (1) trichloride phosphorus and isomeric tridecanol are used as raw materials, and benzene is used as solvent to react, although the yield of the product is high, but benzene has certain carcinogenicity, and in industrial production, benzene is generally avoided as a solvent; (2) ester exchange reaction is carried out under the action of catalyst with phosphite and isomeric tridecanol as raw materials.

[0004] The above-mentioned catalyst for ester exchange reaction with phosphite, isomeric tridecanol as raw materials is generally potassium carbonate, but in actual use, there is a problem that the catalytic efficiency of potassium carbonate is low, which leads to slow reaction process, and reduces the synthesis efficiency. SUMMARY

[0005] In order to improve the reaction process and improve the synthesis efficiency, the present application provides a synthesis process of a phenol-free phosphite antioxidant TTDP.

[0006] The synthesis process of a phenol-free phosphite antioxidant TTDP provided by the present application adopts the following technical scheme: a synthesis process of a phenol-free phosphite antioxidant TTDP, taking trialkyl phosphite and isomeric tridecanol as raw materials, under the catalysis of alkoxy aluminum, through distillation and purification, to obtain.

[0007] By adopting the above technical scheme, the catalytic efficiency of the catalyst is positively correlated with its catalytic activity. Among the catalysts commonly used in the current ester exchange reaction, the catalytic activity of potassium salt is obviously higher than that of sodium salt, lithium salt and alkoxy aluminum. Therefore, the catalyst commonly used in the current ester exchange reaction is generally potassium carbonate, and the catalytic efficiency of potassium carbonate should be the highest.

[0008] However, this application creatively discovers that using aluminum alkoxy as a catalyst significantly improves the transesterification process of trialkyl phosphite and isotridecyl alcohol compared to potassium carbonate. In actual testing, under the same reaction time, the process using aluminum alkoxy achieved a purity (i.e., effective content) of the antioxidant TTDP of 99.25% or higher, while the process using potassium carbonate or other catalysts resulted in a purity of less than 52.87%. This indicates that aluminum alkoxy has higher catalytic efficiency and produces a greater effective content of TTDP within the same timeframe, thus proving the aforementioned findings.

[0009] In other words, compared with catalysts such as potassium carbonate, aluminum alkoxy exhibits higher catalytic efficiency for trialkyl phosphite and isotridecyl alcohol, effectively increasing the effective content of newly generated antioxidant TTDP per unit time, significantly accelerating the reaction process, and greatly improving the preparation efficiency of TTDP.

[0010] Optionally, the specific steps of distillation are as follows:

[0011] S1. Under normal pressure, the mixture of trialkyl phosphite, isotridecyl alcohol, and aluminum alkoxy is heated to 110-120℃ in stages and the reaction is maintained at this temperature for 0.8-1.2h.

[0012] S2. Over a period of 5-6 hours, slowly raise the temperature to 190-200℃ and slowly reduce the pressure to absolute pressure to release the gas generated in the reaction. Maintain the temperature for 0.8-1.2 hours, remove the distillate, and obtain the reaction solution.

[0013] By adopting the above technical solution, rapid heating and depressurization will cause triethyl phosphite to be evaporated, resulting in the reaction only stopping at disubstituted products. This will result in the product not being the optimal antioxidant component. However, by slowly heating and depressurizing in step S2, a large amount of trisubstituted products are generated, achieving the optimal antioxidant component. At the same time, the effective content is increased, ensuring that TTDP has high purity.

[0014] When direct heating and direct decompression are used in step S2, the yield of TTDP is 59.62% and the purity is 75.41%. When staged heating and staged decompression are used, the yield of TTDP is 88.29% or higher and the purity is 99.25% or higher.

[0015] Optionally, in step S1, the specific steps for segmented heating are as follows:

[0016] First heating step: Heat the mixture to 50-60℃ and react for 15-20 minutes;

[0017] Second stage heating: Heat the mixture to 85-95℃ and react for 20-30 minutes;

[0018] Three-stage heating: Heat the mixture to 110-120℃ and react for 15-20 minutes.

[0019] By adopting the above technical solution, the segmented heating in step S1 promotes the complete evaporation of the newly generated methanol or ethanol in the transesterification reaction, reduces the reaction between the newly generated alcohol and ester, ensures the normal progress of the trialkyl phosphite and isotridecyl alcohol reaction, and ensures that TTDP has a high yield and purity.

[0020] When staged heating is used in step S1, the yield of TTDP is 88.29% or higher and the purity is 99.25% or higher. When direct heating is used, the yield of antioxidant TTDP is 82.39% and the purity is 88.86%.

[0021] Optionally, in step S2, heating and depressurization are performed simultaneously.

[0022] By adopting the above technical solution, heating and depressurization are carried out simultaneously, which helps to reduce the solubility of newly generated methanol or ethanol, promotes complete transesterification reaction, and ensures that the antioxidant TTDP has a high yield and purity.

[0023] Optionally, the specific purification steps are as follows: cool the reaction solution to 110-130℃, add the adsorbent, stir and mix, cool to 85-90℃, filter to remove impurities, and the product is obtained.

[0024] By adopting the above technical solution and purification process, the purification effect of the product is good, and the purity of the prepared antioxidant TTDP can reach 99.25% or higher, with a maximum of 99.44%.

[0025] Optionally, during purification, the weight ratio of the adsorbent added to aluminum alkoxy is (9-11):1.

[0026] By adopting the above technical solution, it was found in the experiment that when the amount of adsorbent used was excessive, the purity of TTDP was not further improved. When the amount of adsorbent added was within the above range, the prepared antioxidant TTDP had high purity. Considering the overall cost, the amount of adsorbent added should be within the range of a weight ratio of (9-11):1 with aluminum alkoxy.

[0027] Optionally, in step S1, the weight ratio of trialkyl phosphite, isotridecyl alcohol, and aluminum alkoxy is (50-250):(10-90):0.35.

[0028] Optionally, in step S1, the weight ratio of trialkyl phosphite, isotridecyl alcohol, and aluminum alkoxy is 150:50:0.35.

[0029] By adopting the above technical solution, when the weight ratio of trialkyl phosphite, isotretinoin, and aluminum alkoxy is outside the above range, the yield of antioxidant TTDP decreases from 88.29% to 76.56% and the purity decreases from 99.25% to 77.28%, indicating that the weight ratio of trialkyl phosphite, isotretinoin, and aluminum alkoxy should be within the above range.

[0030] Optionally, in step S1, the trialkyl phosphite is one of trimethyl phosphite, triethyl phosphite, tributyl phosphite, triallyl phosphite, triisopropyl phosphite, and triphenyl phosphite.

[0031] Optionally, in step S1, the aluminum alkoxy is a mixture of one or more of the following: aluminum triethoxy, aluminum tripropoxy, aluminum triisopropoxy, aluminum tributoxy, aluminum triisobutoxy, aluminum trisec-butoxy, aluminum tritert-butoxy, aluminum ethoxydiethylaluminum, aluminum ethoxydipropylaluminum, aluminum ethoxydiisopropylaluminum, aluminum ethoxydibutylaluminum, aluminum ethoxydiisobutylaluminum, aluminum ethoxydisec-butylaluminum, and aluminum ethoxyditert-butoxy.

[0032] By adopting the above technical solution, when using tripropoxyaluminum, triisopropoxyaluminum, or a mixture of the two, the yield and purity of the antioxidant TTDP do not fluctuate much compared to triethoxyaluminum, ensuring a high effective content of TTDP and a purity of over 99%. Compared to using other catalysts, the purity is significantly increased.

[0033] In summary, this application has the following beneficial effects:

[0034] 1. The synthesis process of this application uses aluminum alkoxy to catalyze the reaction of trialkyl phosphite and isotridecyl alcohol. Compared with other catalysts such as potassium carbonate, aluminum alkoxy significantly increases the effective content of TTDP, with a purity of up to 99.25% or higher. This significantly improves the reaction process and greatly enhances the synthesis efficiency of antioxidant TTDP, which is beneficial for the large-scale industrial preparation of TTDP.

[0035] 2. In this application, the staged heating in step S1 promotes the complete evaporation of the newly formed alcohol and ensures a high effective content, thereby ensuring the normal progress of the reaction of trialkyl phosphite and isotridecyl alcohol and ensuring that the antioxidant TTDP has a high yield and purity.

[0036] 3. In this application, by staged heating and staged depressurization in step S2, the evaporation of the raw material triethyl phosphite is reduced, which promotes complete reaction and high effective content, and ensures that the antioxidant TTDP has a high yield and purity. Detailed Implementation

[0037] The present application will be further described in detail below with reference to the embodiments.

[0038] Example

[0039] The TTDP referred to in this application is the antioxidant triisotridecyl phosphite, hereinafter referred to as antioxidant TTDP;

[0040] The ambient pressure is 0.1013 MPa, and the absolute pressure is 50 mmHg.

[0041] The yield and purity of the antioxidant TTDP prepared in each example and comparative example are recorded in Table 1.

[0042] Example 1

[0043] A synthesis process for a phenol-free phosphite antioxidant TTDP, the specific steps of which are as follows:

[0044] Add 50g of trialkyl phosphite (triethyl phosphite), 10g of isotridecyl alcohol, and 0.35g of aluminum alkoxy (triethoxy aluminum) to a reaction flask, then distill and purify to obtain;

[0045] The specific steps of distillation are as follows:

[0046] S1. Under normal pressure, the mixture of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate is heated to 110°C in stages and kept at that temperature for 50 min.

[0047] The specific steps for staged heating are as follows:

[0048] First heating step: Heat the mixture to 50°C and maintain the temperature for 15 minutes;

[0049] Second stage heating: Heat the mixture to 85℃ and maintain the temperature for 20 minutes;

[0050] Three-stage heating: Heat the mixture to 110℃ and maintain the temperature for 15 minutes.

[0051] S2. Then, over a period of 5 hours, the mixture is slowly heated to 190°C and slowly depressurized to absolute pressure to release the gas generated in the reaction. The reaction is maintained at this temperature for 0.8 hours. The distillate is then removed to obtain the reaction solution.

[0052] The specific steps of purification are as follows:

[0053] After removing the distillate, the reaction solution was naturally cooled from 25°C to 110°C, then 3.15g of adsorbent (4A molecular sieve) was added. The mixture was stirred and mixed for 30 minutes, and then naturally cooled to 85°C. The precipitate was removed by filtration, and the antioxidant TTDP was obtained.

[0054] Comparative Examples 1-11

[0055] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from Example 1 in the following aspects: the catalyst used is as follows:

[0056] Comparative Example 1: Use an equal amount of potassium carbonate instead of aluminum triethoxylate.

[0057] Comparative Example 2: Use an equal amount of potassium hydroxide instead of aluminum triethoxy.

[0058] Comparative Example 3: Using an equal amount of potassium tert-butoxide instead of aluminum triethoxy.

[0059] Comparative Example 4: Use an equal amount of sodium carbonate instead of aluminum triethoxylate.

[0060] Comparative Example 5: Use an equal amount of sodium hydroxide instead of aluminum triethoxy.

[0061] Comparative Example 6: Use an equal amount of sodium methoxide instead of aluminum triethoxy.

[0062] Comparative Example 7: Use an equal amount of choline instead of aluminum triethoxylate.

[0063] Comparative Example 8: Use an equal amount of tetramethylguanidine instead of aluminum triethoxy.

[0064] Comparative Example 9: Use an equal amount of tetraethylammonium hydroxide instead of aluminum triethoxy.

[0065] Comparative Example 10: Use an equal amount of p-toluenesulfonic acid instead of aluminum triethoxy.

[0066] Comparative Example 11: Use an equal amount of phosphorous acid instead of aluminum triethoxy.

[0067] Examples 2-3, Comparative Example 12

[0068] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from Example 1 in that the distillation conditions are as follows:

[0069] Example 2: Step S1 is the same as S1 in Example 1; Step S2: Over a period of 5.5 hours, the temperature is slowly increased to 195°C and then slowly reduced to absolute pressure to remove the gas and distillate generated in the reaction. The reaction is then maintained at this temperature for 1.0 hour.

[0070] Example 3: Step S1 is the same as S1 in Example 1; Step S2: Over a period of 6 hours, the temperature is slowly increased to 200°C and then slowly reduced to absolute pressure to remove the gas and distillate generated in the reaction. The reaction is then maintained at this temperature for 1.2 hours.

[0071] Comparative Example 12: Step S1 is the same as S1 in Example 1; in step S2, the temperature is rapidly increased to 195°C within 5 minutes, and the pressure is rapidly reduced to absolute pressure to remove the gas and distillate generated in the reaction, and the reaction is maintained at this temperature for 1.0 h.

[0072] Examples 4-5, Comparative Example 13

[0073] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from Example 1 in that step S1 is as follows: Example 4, step S1 is: under normal pressure, a mixture of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate is heated to 110°C in stages and kept at that temperature for 61 min.

[0074] The specific steps for staged heating are as follows:

[0075] First heating step: Heat the mixture to 55°C and maintain the temperature for 18 minutes;

[0076] Second stage heating: Heat the mixture to 90℃ and maintain the temperature for 25 minutes;

[0077] Three-stage heating: The mixture is heated to 115℃ and kept at that temperature for 18 minutes.

[0078] Example 5, Step S1: Under normal pressure, the mixture of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate was heated to 120°C in stages and kept at that temperature for 65 minutes.

[0079] The specific steps for staged heating are as follows:

[0080] First heating step: Heat the mixture to 60°C and maintain the temperature for 20 minutes;

[0081] Second stage heating: Heat the mixture to 95℃ and maintain the temperature for 30 minutes;

[0082] Three-stage heating: Heat the mixture to 120℃ and maintain the temperature for 15 minutes.

[0083] Comparative Example 13, Step S1: Under normal pressure, the mixture of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate was directly heated to 120°C and kept at that temperature for 50 min.

[0084] Implementation 6-8

[0085] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from Example 1 in the use of aluminum alkoxy, as follows:

[0086] Example 6: Using an equal amount of aluminum tripropoxy instead of aluminum triethoxy.

[0087] Example 7: Using an equal amount of aluminum triisopropoxy instead of aluminum triethoxy.

[0088] Example 8: A mixture of equal amounts of aluminum tripropoxy and aluminum triisopropoxy in a weight ratio of 1:1 was used instead of aluminum triethoxy.

[0089] Implement 9-11

[0090] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from Example 1 in the amount of triethyl phosphite and isotretinoin used, as follows:

[0091] Example 1: The weight ratio of triethyl phosphite, isotridecyl alcohol and aluminum triethoxylate was 50:10:0.35.

[0092] Example 9: The weight ratio of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate was 150:50:0.35.

[0093] Example 10: The weight ratio of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate was 250:90:0.35.

[0094] Example 11: The weight ratio of triethyl phosphite, isotridecyl alcohol, and aluminum triethoxylate was 300:120:0.35.

[0095] It should be noted that the trialkyl phosphite can be selected from trimethyl phosphite, triethyl phosphite, tributyl phosphite, triallyl phosphite, triisopropyl phosphite, and triphenyl phosphite. The above selection does not have a significant impact on the performance test results. This application only briefly introduces triethyl phosphite as an example.

[0096] Implementation 12-14

[0097] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from Example 1 in that the specific purification steps are as follows:

[0098] Example 12: The reaction solution after removing the distillate was naturally cooled from 25°C to 120°C, 3.15g of adsorbent (4A molecular sieve) was added, the mixture was stirred and mixed for 30 minutes, and then naturally cooled to 88°C. The precipitate was removed by filtration to obtain the antioxidant TTDP.

[0099] Example 13: The reaction solution after removing the distillate was naturally cooled from 25°C to 130°C, 3.15g of adsorbent (4A molecular sieve) was added, the mixture was stirred and mixed for 30 minutes, and then naturally cooled to 90°C. The precipitate was removed by filtration to obtain the antioxidant TTDP.

[0100] Example 14: The reaction solution after removing the distillate was naturally cooled from 25°C to 100°C, 3.15g of adsorbent (4A molecular sieve) was added, the mixture was stirred and mixed for 30 minutes, and then naturally cooled to 75°C. The precipitate was removed by filtration to obtain the antioxidant TTDP.

[0101] Implementation 15-17

[0102] A method for synthesizing a phenol-free phosphite antioxidant TTDP differs from that in Example 1 in that...

[0103] During purification, the amount of adsorbent (4A molecular sieve) added is as follows:

[0104] In Example 1, the weight ratio of 4A molecular sieve to aluminum alkoxy is 3.15:0.35, which is 9:1.

[0105] In Example 15, the weight ratio of 4A molecular sieve to alkoxyaluminum was 10:1.

[0106] In Example 16, the weight ratio of 4A molecular sieve to alkoxyaluminum was 11:1.

[0107] In Example 17, the weight ratio of 4A molecular sieve to aluminum alkoxy is 2:0.35, or 5.71:1.

[0108] Performance testing

[0109] The antioxidant TTDP prepared in the examples and comparative examples was subjected to the following performance tests, and the test results are recorded in Table 1.

[0110] Detection methods

[0111] 1. Refractive index: The refractive index of the antioxidant TTDP at 25℃ was tested according to standard GB / T 6488-2008.

[0112] 2. Viscosity: The kinematic viscosity of the antioxidant TTDP at 25°C was tested according to standard GB / T 10247-2008.

[0113] Table 1 Performance Test Results

[0114]

[0115]

[0116] As shown in Table 1, in Example 1, the use of aluminum alkoxy as a catalyst resulted in a yield of 88.29% or higher and a purity of 99.25% or higher for the prepared antioxidant TTDP. In contrast, in Comparative Examples 1-11, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium tert-butoxide, sodium methoxide, choline, tetramethylguanidine, tetraethylammonium hydroxide, p-toluenesulfonic acid, and phosphorous acid were used instead of aluminum alkoxy as catalysts, resulting in a maximum purity of only 52.87% for the prepared antioxidant TTDP.

[0117] This indicates that, under the same reaction time, using aluminum alkoxy catalysts results in a more complete and efficient reaction of trialkyl phosphite and isotretinoin compared to other catalysts, leading to a higher effective content of the antioxidant TTDP and significantly improving the synthesis efficiency; while other catalysts result in incomplete reactions and low catalytic efficiency.

[0118] The difference between Comparative Example 12 and Example 1 is that in step S2, rapid heating and rapid decompression caused some of the trialkyl phosphite to be distilled off, and most of the product remained disubstituted, which was not the optimal component for the antioxidant TTDP. At the same time, the purity of TTDP decreased to 75.41%, which was lower than that of Example 1, and the difference between the two was significant. This indicates that in the preparation process of this application, by using slow heating and slow decompression in step S2, the yield and purity of TTDP can be guaranteed.

[0119] The difference between Comparative Example 12 and Example 1 is that in step S1, rapid heating caused some methanol or ethanol to not evaporate completely, hindering the normal reaction of trialkyl phosphite and isotridecyl alcohol, resulting in the purity of antioxidant TTDP decreasing to 88.86%, and both the yield and purity were lower than in Example 1. This indicates that in the preparation process of this application, by using slow heating in step S1, the yield and purity of TTDP can be guaranteed.

[0120] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A synthesis process for a phenol-free phosphite antioxidant TTDP, characterized in that, The product is obtained by distillation and purification using trialkyl phosphite and isotridecyl alcohol as raw materials under the catalysis of aluminum alkoxy; The specific steps of the distillation are as follows: S1. Under normal pressure, the mixture of trialkyl phosphite, isotridecyl alcohol, and aluminum alkoxy is heated to 110-120℃ in stages and the reaction is maintained at this temperature for 0.8-1.2h. S2. Over a period of 5-6 hours, slowly raise the temperature to 190-200℃ and slowly reduce the pressure to absolute pressure to release the gas generated in the reaction. Maintain the temperature for 0.8-1.2 hours, remove the distillate, and obtain the reaction solution. The trialkyl phosphite is one of trimethyl phosphite, triethyl phosphite, tributyl phosphite, and triallyl phosphite; The alkoxyaluminum is a mixture of one or more of the following: triethoxyaluminum, tripropoxyaluminum, triisopropoxyaluminum, tributoxyaluminum, triisobutoxyaluminum, trisec-butoxyaluminum, tritert-butoxyaluminum, ethoxydiethylaluminum, ethoxydipropylaluminum, ethoxydiisopropylaluminum, ethoxydibutylaluminum, ethoxydiisobutylaluminum, ethoxydisec-butylaluminum, and ethoxyditert-butoxyaluminum.

2. The synthesis process of the phenol-free phosphite antioxidant TTDP according to claim 1, characterized in that, In step S1, the specific steps for segmented heating are as follows: First heating step: Heat the mixture to 50-60℃ and react for 15-20 minutes; Second stage heating: Heat the mixture to 85-95℃ and react for 20-30 minutes; Three-stage heating: Heat the mixture to 110-120℃ and react for 15-20 minutes.

3. The synthesis process of the phenol-free phosphite antioxidant TTDP according to claim 1, characterized in that: In step S2, heating and depressurization are performed simultaneously.

4. The synthesis process of the phenol-free phosphite antioxidant TTDP according to claim 1, characterized in that, The specific purification steps are as follows: cool the reaction solution to 110-130℃, then add the adsorbent, stir and mix, cool to 85-90℃, filter to remove impurities, and the product is obtained.

5. The synthesis process of the phenol-free phosphite antioxidant TTDP according to claim 4, characterized in that: During purification, the weight ratio of the adsorbent added to aluminum alkoxy is (9-11):

1.

6. The synthesis process of the phenol-free phosphite antioxidant TTDP according to claim 1, characterized in that: The weight ratio of trialkyl phosphite, isotridecyl alcohol, and aluminum alkoxy is (50-250):(10-90):0.

35.

7. The synthesis process of the phenol-free phosphite antioxidant TTDP according to claim 6, characterized in that: The weight ratio of trialkyl phosphite, isotridecyl alcohol, and aluminum alkoxy is 150:50:0.35.

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