Antioxidant 3114 and process for its preparation and use

Abstract

The application relates to the technical field of antioxidant synthesis, in particular to an antioxidant 3114 and a preparation method and application thereof. The preparation method comprises the following steps: (1) mixing tropine base (CAS number 120-29-6), polyformaldehyde and dimethylformamide, and then heating to obtain a reaction product A; (2) in an inert atmosphere, reacting cyanuric acid, hexamethylene imine, 2,6-di-tert-butylphenol and the reaction product A to obtain a reaction product B; and (3) cooling and crystallizing the reaction product B, carrying out solid-liquid separation, washing with methanol and drying to obtain the antioxidant 3114. The method can be used for preparing the antioxidant 3114, and high raw material conversion rate and selectivity of the target product antioxidant 3114 can be obtained.

Description

Technical Field

[0001] This invention relates to the field of antioxidant synthesis technology, specifically to an antioxidant 3114 and its preparation method and application. Background Technology

[0002] Antioxidant 3114 (CAS No.: 27676-62-6) is named 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid. It belongs to the hindered phenolic antioxidant class and can be used in polyolefins (such as polyethylene and polypropylene), polyesters and synthetic rubbers to increase the stability of the corresponding products. It can be used alone or in synergy with other antioxidants to increase the stability of the corresponding products, especially photothermal stability.

[0003] Currently, in industry, cyanuric acid, paraformaldehyde, and 2,6-di-tert-butylphenol are used as raw materials to carry out the reaction in the presence of a catalyst and an aqueous methanol solution. However, the reaction conditions are high temperature and high pressure, and the reaction time is relatively long, resulting in low yield and purity of the final antioxidant 3114 product.

[0004] Some literature suggests using cyanuric acid, paraformaldehyde, and 2,6-di-tert-butylphenol as raw materials, and reacting them in a nitrogen atmosphere with a catalyst. This reaction does not require high pressure, and the final product can only yield antioxidant 3114 with a yield of about 95%.

[0005] Patent CN104418814B discloses a method for synthesizing hindered phenolic antioxidant 3114. This method employs a two-step reaction. The first step involves reacting to obtain the intermediate (3,5-di-tert-butylphenol-4-hydroxy)benzyl methyl ether. Then, the intermediate (3,5-di-tert-butylphenol-4-hydroxy)benzyl methyl ether) reacts with isocyanuric acid to obtain antioxidant 3114. While this method is simpler than using a high-pressure reactor for post-processing, it still requires post-processing during both the synthesis of the intermediate and the synthesis of antioxidant 3114. This process is relatively cumbersome, and ultimately only yields antioxidant 3114 with a yield of approximately 95%. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of low product yield in the preparation of antioxidant 3114 in the prior art, and to provide an antioxidant 3114, its preparation method, and its application. This preparation method can produce antioxidant 3114 with a high yield.

[0007] The first aspect of this invention provides a method for preparing antioxidant 3114, the method comprising:

[0008] (1) Tropine (CAS No. 120-29-6), paraformaldehyde and dimethylformamide are mixed and then heated to produce product A;

[0009] (2) In an inert atmosphere, cyanuric acid, hexamethyleneimine, 2,6-di-tert-butylphenol and reaction product A are reacted to obtain reaction product B;

[0010] (3) The reaction product B was cooled and crystallized, solid-liquid separated, washed with methanol and dried to obtain antioxidant 3114.

[0011] Preferably, in step (1), the mass of tropine is 0.5 to 2 wt% of the mass of paraformaldehyde.

[0012] Preferably, in step (1), the ratio of paraformaldehyde to dimethylformamide is 1 g to (10-30) mL.

[0013] Preferably, in step (1), the temperature of the heating reaction is 70~100℃; the heating reaction time is 20~60min.

[0014] Preferably, the molar ratio of cyanuric acid to paraformaldehyde is 1:(3.5~4).

[0015] Preferably, the molar ratio of cyanuric acid to 2,6-di-tert-butylphenol is 1:(3.2~3.6).

[0016] Preferably, the mass of the hexamethyleneimine is 2 to 3 wt% of the mass of paraformaldehyde.

[0017] Preferably, in step (2), the reaction temperature is 100~130℃ and the reaction time is 1.5~3.5h.

[0018] A second aspect of the present invention provides antioxidant 3114 prepared by the preparation method of the present invention.

[0019] A third aspect of the present invention provides the application of the antioxidant 3114 described herein in polypropylene.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) Using the method of the present invention to prepare antioxidant 3114 can achieve a high raw material conversion rate and selectivity of the target product antioxidant 3114;

[0022] (2) The preparation method of the present invention is mild and does not involve high-pressure reaction, thus making it safer;

[0023] (3) The antioxidant 3114 prepared by the present invention has a long oxidation induction period. When the antioxidant 3114 is used in polypropylene, it can increase the antioxidant performance of polypropylene materials. Attached Figure Description

[0024] Figure 1 The above is the 1H NMR spectrum of antioxidant 3114 prepared in Example 1;

[0025] Figure 2 The image shows the carbon NMR spectrum of antioxidant 3114 prepared in Example 1.

[0026] Figure 3 The image shows the infrared spectrum of antioxidant 3114 prepared in Example 1. Detailed Implementation

[0027] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0028] The first aspect of this invention provides a method for preparing antioxidant 3114, the method comprising:

[0029] (1) Tropine (CAS No. 120-29-6), paraformaldehyde and dimethylformamide are mixed and then heated to produce product A;

[0030] (2) In an inert atmosphere, cyanuric acid, hexamethyleneimine, 2,6-di-tert-butylphenol and reaction product A are reacted to obtain reaction product B;

[0031] (3) The reaction product B was cooled and crystallized, solid-liquid separated, washed with methanol and dried to obtain antioxidant 3114.

[0032] In this invention, tropine, paraformaldehyde, and dimethylformyl are heated to obtain reaction product A. Then, reaction product A is reacted with cyanuric acid and 2,6-di-tert-butylphenol in the presence of hexamethyleneimine as a catalyst. This not only yields antioxidant 3114 in high yield but also reduces reaction time. The inventors hypothesize that reacting the paraformaldehyde-containing material first allows for the stable acquisition of formaldehyde monomer-containing material, which is beneficial for increasing the conversion rate of cyanuric acid and the selectivity of antioxidant 3114. Simultaneously, the synergistic effect of tropine and hexamethyleneimine further enhances catalytic activity, allowing the reaction to proceed more effectively.

[0033] In one embodiment, in step (1), the mass of the tropine is 0.5 to 2 wt% of the mass of paraformaldehyde, for example, 0.5 wt%, 1 wt%, 1.2 wt%, 1.3 wt%, 1.5 wt%, 1.8 wt%, or 2 wt%.

[0034] In a preferred embodiment, in step (1), the mass of tropine is 1 to 1.5 wt% of the mass of paraformaldehyde.

[0035] In this invention, the yield of antioxidant 3114 can be further increased by controlling the amount of tropine added. However, the inventors have found that the amount of tropine added must be strictly controlled during the experiment. When too much tropine is added, the yield of antioxidant 3114 will decrease. This may be because excessive tropine may affect the catalytic activity of hexamethyleneimine, or it may be because excessive tropine may cause other side reactions, leading to a decrease in the conversion rate of the raw materials and / or the selectivity of the target product antioxidant 3114.

[0036] In one embodiment, in step (1), paraformaldehyde: dimethylformamide = 1g: (10~30)mL, for example 1g: 10mL, 1g: 11mL, 1g: 12mL, 1g: 13mL, 1g: 14mL, 1g: 15mL, 1g: 16mL, 1g: 17mL, 1g: 18mL, 1g: 19mL, 1g: 20mL, 1g: 21mL, 1g: 22mL, 1g: 23mL, 1g: 24mL, 1g: 25mL, 1g: 26mL, 1g: 27mL, 1g: 28mL, 1g: 29mL, 1g: 30mL.

[0037] In a preferred embodiment, in step (1), paraformaldehyde: dimethylformamide = 1g: (15~20)mL.

[0038] In this invention, the use of the above-mentioned amount of dimethylformamide allows the reaction to proceed more smoothly, reduces the occurrence of side reactions, and thereby increases the selectivity of the target product antioxidant 3114.

[0039] In one embodiment, in step (1), the temperature of the heating reaction is 70~100°C, for example 70°C, 80°C, 90°C, or 100°C.

[0040] In a preferred embodiment, in step (1), the temperature of the heating reaction is 85~95°C.

[0041] In one embodiment, in step (1), the heating reaction time is 20 to 60 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, or 60 minutes.

[0042] In a preferred embodiment, in step (1), the heating reaction time is 30-40 min.

[0043] In the experiment, the inventors studied the need to strictly control the conditions of the heating reaction in order to simultaneously achieve the goal of obtaining a high conversion rate of cyanuric acid and the selectivity of antioxidant 3114. The inventors speculated that this may be because the formaldehyde monomer in the reaction product A obtained under the heating reaction conditions can exist more stably, so that the reaction product A can generate the target product more stably in subsequent reactions, and will not produce or produce little other impurities.

[0044] In this invention, the heating reaction can be carried out in a conventional reaction vessel in the art, and there are no special limitations on the structure of the reaction vessel. This invention will not elaborate on this further.

[0045] In one embodiment, the type of inert atmosphere is not particularly limited and may be nitrogen and / or argon.

[0046] In this invention, the reaction in step (2) is carried out in an inert atmosphere, which can avoid the influence of other impurity gases in the air and better increase the selectivity of antioxidant 3114.

[0047] In one embodiment, the molar ratio of cyanuric acid to paraformaldehyde, based on the provided formaldehyde monomer, is 1:(3.5~4), for example, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, or 1:4.

[0048] In this invention, controlling the ratio of cyanuric acid to paraformaldehyde can make the reaction proceed more smoothly and better increase the conversion rate of cyanuric acid and the yield of antioxidant 3114.

[0049] In one embodiment, the molar ratio of cyanuric acid to 2,6-di-tert-butylphenol is 1:(3.2~3.6), for example, 1:3.2, 1:3.3, 1:3.4, 1:3.5, or 1:3.6.

[0050] In this invention, controlling the ratio of cyanuric acid to 2,6-di-tert-butylphenol can better increase the conversion rate of cyanuric acid and the yield of antioxidant 3114.

[0051] In one embodiment, the hexamethyleneimine is 2 to 3 wt% of the mass of paraformaldehyde, for example, 2 wt%, 2.5 wt%, 2.8 wt%, or 3 wt%.

[0052] In this invention, a specific amount of hexamethyleneimine and tropine work synergistically to ensure the stable existence of formaldehyde monomer, while reducing reaction time and increasing the conversion rate of cyanuric acid and the yield of antioxidant 3114.

[0053] In one embodiment, in step (2), the reaction temperature is 100~130℃, for example 100℃, 110℃, 115℃, 120℃, 125℃, 130℃.

[0054] In a preferred embodiment, in step (2), the reaction temperature is 110~115℃.

[0055] In one embodiment, the reaction time in step (2) is 1.5 to 3.5 hours, for example, 1.5 hours, 1.8 hours, 2 hours, 2.3 hours, 2.5 hours, 2.8 hours, 3 hours, 3.3 hours, or 3.5 hours.

[0056] In a preferred embodiment, the reaction time in step (2) is 2-3 hours.

[0057] In this invention, cyanuric acid, hexamethyleneimine, and 2,6-di-tert-butylphenol can be directly added to the reaction product A in step (1) for reaction.

[0058] In this invention, the cooling crystallization in step (3) is a conventional method in the art, for example, the reaction product B is cooled and crystallized at -2~4°C.

[0059] In this invention, there are no special limitations on the conditions for solid-liquid separation in step (3), and conventional filtration in the art is sufficient.

[0060] In this invention, the method of methanol washing in step (3) is not particularly limited and can be a conventional washing method in the art. This invention will not elaborate on this further. Generally, it is washed 2 to 4 times.

[0061] In this invention, the drying method in step (3) can be atmospheric pressure drying or vacuum drying, preferably vacuum drying. In one embodiment, the vacuum drying temperature is 30~40℃ and the vacuum drying time is 12~24h.

[0062] In this invention, vacuum drying is used, which can avoid the influence of other impurities on the product when drying at normal pressure.

[0063] A second aspect of the present invention provides antioxidant 3114 prepared by the preparation method of the present invention.

[0064] A third aspect of the present invention provides the application of the antioxidant 3114 described herein in polypropylene.

[0065] In this invention, the prepared antioxidant 3114 has a long oxidation induction period. When the antioxidant 3114 is used in polypropylene, it can increase the antioxidant properties of polypropylene materials.

[0066] The antioxidant 3114 of this invention can be used alone in polypropylene or in combination with other antioxidants. In one embodiment, the antioxidant 3114 prepared by this invention is used in combination with antioxidant 330, and the mass ratio of antioxidant 3114 to antioxidant 330 is 1:(0.3~1), preferably 1:(0.5~0.8).

[0067] In one embodiment, after thoroughly mixing the antioxidant mixture with polypropylene powder, the mixture is extruded in a twin-screw extruder, granulated, and dried to obtain modified polypropylene. The extrusion conditions include: temperatures in each zone of the extruder are 180°C, 200°C, 230°C, 220°C, 210°C, 210°C, 210°C, 210°C, and 205°C, respectively; the die head temperature is 185°C; the main extruder speed is 120 r / min; and the feed speed is 15 r / min to obtain modified polypropylene.

[0068] In a preferred embodiment, the antioxidant mixture is antioxidant 3114 and antioxidant 330 in a mass ratio of 1:(0.3~1), preferably 1:(0.5~0.8).

[0069] In a preferred embodiment, the antioxidant mixture is 0.05-0.2 wt% of the polypropylene powder, preferably 0.8 wt%.

[0070] The present invention will be described in detail below through embodiments, but the present invention is not limited thereto.

[0071] Example 1

[0072] Preparation of antioxidant 3114:

[0073] (1) Add 2.4g of tropine, 218g of paraformaldehyde and 3.5L of dimethylformamide to the reaction vessel and mix them. Then react at 95℃ for 40min to obtain material A;

[0074] (2) Add 258g of cyanuric acid, 4.6g of hexamethyleneimine, and 1361g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 3 hours to obtain the reaction product B.

[0075] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0076] The hydrogen NMR spectrum of the prepared antioxidant 3114 is shown below. Figure 1 As shown;

[0077] The carbon NMR spectrum of the prepared antioxidant 3114 is shown below. Figure 2 As shown;

[0078] The infrared spectrum of the prepared antioxidant 3114 is as follows: Figure 3 As shown.

[0079] Example 2

[0080] Preparation of antioxidant 3114:

[0081] (1) Add 1.7g of tropine, 139g of paraformaldehyde and 1.7L of dimethylformamide to the reaction vessel and mix them. Then react at 90°C for 35min to obtain material A.

[0082] (2) Add 160g of cyanuric acid, 3.2g of hexamethyleneimine, and 870g of 2,6-di-tert-butylphenol to the reaction vessel and mix with reaction product A. Then react at 115°C for 2.5h to obtain reaction product B.

[0083] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0084] Example 3

[0085] Preparation of antioxidant 3114:

[0086] (1) Add 3.4g of tropine, 261g of paraformaldehyde and 5L of dimethylformamide to the reaction vessel and mix them. Then react at 90℃ for 35min to obtain material A;

[0087] (2) Add 305g of cyanuric acid, 6.5g of hexamethyleneimine, and 1658g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 2 hours to obtain the reaction product B.

[0088] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0089] Example 4

[0090] Preparation of antioxidant 3114:

[0091] (1) Add 13g of tropine, 261g of paraformaldehyde and 5L of dimethylformamide to the reaction vessel and mix them. Then react at 90℃ for 35min to obtain material A;

[0092] (2) Add 305g of cyanuric acid, 6.5g of hexamethyleneimine, and 1658g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 2 hours to obtain the reaction product B.

[0093] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0094] Example 5

[0095] Preparation of antioxidant 3114:

[0096] (1) Add 3.4g of tropine, 261g of paraformaldehyde and 5L of dimethylformamide to the reaction vessel and mix them. Then react at 120℃ for 35min to obtain material A;

[0097] (2) Add 305g of cyanuric acid, 6.5g of hexamethyleneimine, and 1658g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 2 hours to obtain the reaction product B.

[0098] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0099] Example 6

[0100] Preparation of antioxidant 3114:

[0101] (1) Add 1.3g of tropine, 261g of paraformaldehyde and 5L of dimethylformamide to the reaction vessel and mix them. Then react at 90℃ for 35min to obtain material A;

[0102] (2) Add 305g of cyanuric acid, 6.5g of hexamethyleneimine, and 1658g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 2 hours to obtain the reaction product B.

[0103] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0104] Example 7

[0105] Preparation of antioxidant 3114:

[0106] (1) Add 3.4g of tropine, 261g of paraformaldehyde and 5L of dimethylformamide to the reaction vessel and mix them. Then react at 75°C for 35min to obtain material A.

[0107] (2) Add 305g of cyanuric acid, 6.5g of hexamethyleneimine, and 1658g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 2 hours to obtain the reaction product B.

[0108] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0109] Comparative Example 1

[0110] Preparation of antioxidant 3114:

[0111] (1) Add 261g of paraformaldehyde and 5L of dimethylformamide to the reactor and mix them. Then react at 90℃ for 35min to obtain material A;

[0112] (2) Add 305g of cyanuric acid, 6.5g of hexamethyleneimine, and 1658g of 2,6-di-tert-butylphenol to the reaction vessel and mix with the reaction product A. Then react at 110°C for 2 hours to obtain the reaction product B.

[0113] (3) After the reaction product B is rapidly cooled to room temperature, it is cooled and crystallized at 1±2℃, filtered, the filter cake is washed with methanol 3 times, and then vacuum dried at 35℃ for 12h to obtain antioxidant 3114.

[0114] Performance testing

[0115] 1. The conversion rate of cyanuric acid, the selectivity of antioxidant 3114, and the yield of antioxidant 3114 were tested in the examples and comparative examples, respectively.

[0116] The conversion rate of cyanuric acid is calculated as follows: % = [(moles of cyanuric acid fed - moles of cyanuric acid remaining) / moles of cyanuric acid fed] × 100%;

[0117] Selectivity of antioxidant 3114 (%) = (number of moles of antioxidant 3114 produced / total number of moles of product) × 100%;

[0118] The yield % of antioxidant 3114 = the conversion rate of cyanuric acid × the selectivity of antioxidant 3114.

[0119] 2. Antioxidant 3114 and antioxidant 330 prepared in the examples and comparative examples were mixed (mass ratio 1:0.5) to obtain antioxidant mixtures. After the antioxidant mixtures were thoroughly mixed with polypropylene powder, they were extruded in a twin-screw extruder, granulated, and dried to obtain the test group. The extrusion conditions included: temperatures of each zone of the extruder were 180℃, 200℃, 230℃, 220℃, 210℃, 210℃, 210℃, 210℃, and 205℃, respectively; the die head temperature was 185℃; the main engine speed was 120 r / min; and the feed speed was 15 r / min. The oxidation induction period (OIT, in minutes) of the test group was tested according to the national standard GB / T 19466.1-2004, and the test temperature was 200℃.

[0120] The test results show that the antioxidant 3114 prepared by this invention can achieve a high raw material conversion rate and selectivity of the target product antioxidant 3114; moreover, the prepared antioxidant 3114 has a long oxidation induction period, and when the obtained antioxidant 3114 is used in polypropylene, it can increase the antioxidant performance of polypropylene materials.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing antioxidant 3114, characterized in that, The preparation method includes: (1) Tropine, paraformaldehyde and dimethylformamide are mixed and then heated to produce product A; (2) In an inert atmosphere, cyanuric acid, hexamethyleneimine, 2,6-di-tert-butylphenol and reaction product A are reacted to obtain reaction product B; (3) The reaction product B was cooled and crystallized, solid-liquid separated, washed with methanol and dried to obtain antioxidant 3114.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass of tropine is 0.5 to 2 wt% of the mass of paraformaldehyde.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), paraformaldehyde: dimethylformamide = 1g: (10~30)mL.

4. The preparation method according to claim 1 or 2, characterized in that, In step (1), the temperature of the heating reaction is 70~100℃; the heating reaction time is 20~60min.

5. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of cyanuric acid to paraformaldehyde is 1:(3.5~4).

6. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of cyanuric acid to 2,6-di-tert-butylphenol is 1:(3.2~3.6).

7. The preparation method according to claim 1 or 2, characterized in that, The mass of the hexamethyleneimine is 2-3 wt% of the mass of paraformaldehyde.

8. The preparation method according to claim 1 or 2, characterized in that, In step (2), the reaction temperature is 100~130℃; the reaction time is 1.5~3.5h.

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