Preparation method of antioxidant 330

Abstract

The present invention provides a preparation method of an antioxidant 330, which belongs to the field of organic synthesis technology. The present invention mixes 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst and an organic solvent, reacts to obtain an antioxidant 330; the composite catalyst includes gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-o-phenanthroline. The method of the present invention has cheap and easy-to-obtain raw materials, simple operation, mild reaction conditions, and easy separation and purification of products; the target product is obtained in high yield, is suitable for industrial large-scale production, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and in particular to a method for preparing an antioxidant 330. Background Art

[0002] 1,3,5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (Antioxidant 330) is a hindered phenol antioxidant characterized by excellent heat resistance, non-polluting, non-staining, and low volatility. It is suitable as an antioxidant stabilizer for various polymers and organic materials. It exhibits synergistic effects when combined with auxiliary antioxidants such as phosphites, thioesters, benzofuranones, and carbon radical scavengers, imparting excellent processing stability and long-term stability to finished products. It is commonly used as an excellent antioxidant for high-density polyethylene, polypropylene, and rubber. It is also used in plastic products such as polyvinyl chloride, polyamide, ABS resin, and polyester. Compared to traditional antioxidants, it is highly effective, low-toxic, and non-polluting, thus holding great promise for industrial applications.

[0003] Currently, a variety of synthesis methods for hindered phenol antioxidant 330 have been disclosed, but there are still many defects, such as the need to improve the reaction yield and simplify the reaction process. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing an antioxidant 330, which has a simple process and a high product yield.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing an antioxidant 330, comprising the following steps:

[0007] 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst, and an organic solvent are mixed and reacted to obtain antioxidant 330;

[0008] The composite catalyst comprises gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-phenanthroline.

[0009] Furthermore, the preparation method of 1,3,5-trichloromethyl-2,4,6-trimethylbenzene includes: mixing a carbon nanotube-loaded acid catalyst, mesitylene, 37 wt% concentrated hydrochloric acid and paraformaldehyde, and reacting to obtain 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; the reaction temperature is 35-45° C., and the reaction time is 0.5-1.5 h.

[0010] Furthermore, the preparation method of the carbon nanotube-supported acid catalyst includes:

[0011] The carbon nanotubes are mixed with concentrated nitric acid and treated with acid to obtain acidified carbon nanotubes; the ethanol suspension of the acidified carbon nanotubes is mixed with tetraisopropyl titanate until it becomes a sol state, and after drying, the obtained dry product is immersed in an acid solution, vacuum dried, and calcined to obtain a carbon nanotube-supported acid catalyst.

[0012] Furthermore, the preparation method of the silica-supported phosphotungstic acid includes: mixing ultrafine silica and phosphotungstic acid in an aqueous phase, and sequentially performing room temperature impregnation, filtering, drying and calcining to obtain a silica-supported phosphotungstic acid catalyst; the mass ratio of the ultrafine silica and phosphotungstic acid is 0.5~5:1; the room temperature impregnation time is 12~36h; the drying temperature is 100°C and the time is 2~4h; the calcination temperature is 200°C and the time is 2~5h.

[0013] Furthermore, the molar ratio of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene to 2,6-di-tert-butylphenol is 1:2-6.

[0014] Furthermore, in terms of mass percentage, the mass of the silica-supported phosphotungstic acid is 1-5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; and the mass of the composite catalyst is 2-5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene.

[0015] Furthermore, the mass ratio of gadolinium trifluoromethanesulfonate to 3,4,7,8-tetramethyl-1,10-phenanthroline in the composite catalyst is 1:0.05-0.2.

[0016] Furthermore, the organic solvent includes 18-crown-6 and also includes dichloromethane, chloroform or carbon tetrachloride.

[0017] Furthermore, the reaction is carried out under reflux conditions; the reaction time is 12 to 36 hours.

[0018] The present invention uses silica-supported phosphotungstic acid as both an acid source and catalyst, not only providing an acidic environment but also catalyzing the synthesis of 1,3,5-trichloromethyl-2,4,6-trimethylbenzene and 2,6-di-tert-butylphenol. Furthermore, the present invention utilizes a specific composite catalyst in synergistic catalysis with the silica-supported phosphotungstic acid, significantly accelerating the reaction process. This results in a high yield of ≥99% for the target antioxidant 330. Furthermore, the present invention's method for preparing antioxidant 330 utilizes a single-step reaction, readily available and inexpensive raw materials, is simple to operate, operates under mild reaction conditions, and allows for easy separation and purification of the product, making it suitable for large-scale industrial production and promising application prospects. DETAILED DESCRIPTION

[0019] The present invention provides a method for preparing an antioxidant 330, comprising the following steps:

[0020] 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst, and an organic solvent are mixed and reacted to obtain antioxidant 330;

[0021] The composite catalyst comprises gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-phenanthroline.

[0022] In the present invention, the preparation method of 1,3,5-trichloromethyl-2,4,6-trimethylbenzene preferably comprises: mixing a carbon nanotube-supported acid catalyst, mesitylene, 37 wt% concentrated hydrochloric acid and paraformaldehyde, and reacting the mixture to obtain 1,3,5-trichloromethyl-2,4,6-trimethylbenzene.

[0023] In the present invention, the preparation method of the carbon nanotube-supported acid catalyst preferably comprises: adding carbon nanotubes to 90 wt% concentrated nitric acid, heating and refluxing for 20 minutes, filtering, washing thoroughly with deionized water, and drying in a vacuum oven to obtain acid-treated carbon nanotubes; adding the acid-treated carbon nanotubes to anhydrous ethanol and stirring until a suspension is formed; adding tetraisopropyl titanate dropwise to the obtained suspension, continuing stirring until a sol is formed, drying, and adding the obtained dry powder to a 1.0 mol / L aqueous sulfuric acid solution. The mixture is immersed for 5 to 6 hours, filtered, and then vacuum-dried at 100° C., heated to 300 to 600° C., calcined for 0.5 to 2.0 hours, and naturally cooled to room temperature to obtain a carbon nanotube-supported acid catalyst; the mass ratio of the acid-treated carbon nanotubes to tetraisopropyl titanate is preferably 1:0.05 to 0.3, more preferably 1:0.1 to 0.2; the present invention has no special restrictions on the usage ratio of the acid-treated carbon nanotubes to anhydrous ethanol and the usage ratio of the dry powder to the sulfuric acid aqueous solution, as long as the amount of anhydrous ethanol and sulfuric acid solution is sufficient.

[0024] In the present invention, the molar ratio of mesitylene, 37 wt% concentrated hydrochloric acid (calculated as HCl) and paraformaldehyde (calculated as formaldehyde) is preferably 1:4.0-4.3:5.2-5.8, more preferably 1:4.1:5.6; the mass ratio of the carbon nanotube-supported acid catalyst to mesitylene is preferably 1:40-60, more preferably 1:45-50.

[0025] According to the present invention, the carbon nanotube-supported acid catalyst, mesitylene, 37 wt% concentrated hydrochloric acid and paraformaldehyde are mixed, and the reaction temperature is preferably 35-45° C., more preferably 40° C.; the reaction time is preferably 0.5-1.5 h, more preferably 1.0 h; after the reaction, the mixture is cooled to room temperature to precipitate a solid, dried, and then petroleum ether is added and refluxed for 30 min. The solid is naturally cooled to precipitate, filtered, washed with deionized water, and vacuum dried to obtain 1,3,5-trichloromethyl-2,4,6-trimethylbenzene.

[0026] In the present invention, the preparation method of the silica-supported phosphotungstic acid preferably comprises: mixing ultrafine silica and phosphotungstic acid in an aqueous phase, and sequentially performing room temperature impregnation, filtration, drying and calcination to obtain a silica-supported phosphotungstic acid catalyst; the mesh size of the ultrafine silica is preferably 1000 mesh; the mass ratio of the ultrafine silica and phosphotungstic acid is preferably 0.5-5:1; the room temperature impregnation time is preferably 12-36 hours, more preferably 18-24 hours; the drying temperature is preferably 100°C, the time is preferably 2-4 hours, more preferably 3 hours; the calcination temperature is preferably 200°C, and the time is preferably 2-5 hours, more preferably 3-4 hours.

[0027] In the present invention, the molar ratio of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene to 2,6-di-tert-butylphenol is preferably 1:2-6; the mass of the silica-supported phosphotungstic acid is preferably 1-5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; and the mass of the composite catalyst is preferably 2-5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene.

[0028] In the present invention, the mass ratio of gadolinium trifluoromethanesulfonate to 3,4,7,8-tetramethyl-1,10-phenanthroline in the composite catalyst is preferably 1:0.05-0.2; the composite catalyst is a mixture of gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-phenanthroline.

[0029] In the present invention, the organic solvent preferably includes 18-crown-6 and also includes dichloromethane, chloroform or carbon tetrachloride; the present invention has no special limitation on the distribution ratio of each component in the organic solvent, which can be adjusted according to actual needs; the present invention has no special limitation on the amount of the organic solvent, which can be adjusted according to needs to ensure the smooth progress of the reaction.

[0030] In the present invention, the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, composite catalyst and organic solvent are mixed and reacted under reflux conditions; the reaction time is preferably 12 to 36 hours.

[0031] After the reaction is completed, the present invention preferably filters the obtained product and then recrystallizes the obtained solid using petroleum ether to obtain antioxidant 330.

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. Example 1

[0033] Preparation of silica-supported phosphotungstic acid catalyst:

[0034] 50 kg of ultrafine silica (1000 mesh) and 10 kg of phosphotungstic acid (CAS No.: 12501-23-4) were added to 100 L of water in sequence, and the mixture was immersed at room temperature for 18 hours. The mixture was filtered and the filter cake was dried at 100 °C for 3 hours and then calcined at 200 °C for 5 hours to obtain silica-supported phosphotungstic acid.

[0035] Preparation of carbon nanotube-supported acid catalyst:

[0036] The carbon nanotubes were added to a sufficient amount of 90 wt% concentrated nitric acid, heated under reflux for 20 minutes, filtered, thoroughly washed with deionized water, and dried in a vacuum oven to obtain acid-treated carbon nanotubes; the acid-treated carbon nanotubes were added to a sufficient amount of anhydrous ethanol, stirred until a suspension was formed, tetraisopropyl titanate was dropwise added to the suspension, stirred continuously until a sol-like state was formed, dried, and crushed to obtain a powder; wherein the mass ratio of the acid-treated carbon nanotubes to tetraisopropyl titanate was 1:0.3; the obtained dry powder was added to a sufficient amount of 1.0 mol / l sulfuric acid aqueous solution, immersed for 6 hours, filtered, and completely dried at 100° C. in a vacuum oven, heated to 600° C., calcined for 1 hour, and naturally cooled to room temperature to obtain a carbon nanotube-supported acid catalyst;

[0037] At room temperature, mesitylene, 37 wt% concentrated hydrochloric acid, and paraformaldehyde were added to a reactor in a molar ratio of 1:4.1:5.6. A carbon nanotube-supported acid catalyst (mesitylene to catalyst mass ratio of 100:2) was then added. The temperature was raised to 40°C and the reaction was allowed to proceed for 90 minutes. After the reaction was complete, the temperature was lowered to room temperature to precipitate a solid. The solid was dried, added to a sufficient amount of petroleum ether, and refluxed for 30 minutes. The precipitated solid was naturally cooled, filtered, washed with deionized water, and vacuum-dried to obtain 1,3,5-trichloromethyl-2,4,6-trimethylbenzene in a yield of 98.5%.

[0038] The 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst (the mass ratio of gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-o-phenanthroline is 1:0.1) and an organic solvent (18-crown-6 and dichloromethane in a volume ratio of 1:3) are mixed, and the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene and 2,6-di-tert-butylphenol are added. The molar ratio of phenol is 1:5; the mass of the silica-supported phosphotungstic acid is 3% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; and the mass of the composite catalyst is 5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene. The reaction is carried out for 24 hours. The resulting product is filtered and the resulting solid is recrystallized with petroleum ether to obtain antioxidant 330 with a yield of 99.2% and a melting point of 240-243°C. Example 2

[0039] The only difference from Example 1 is:

[0040] The 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst (the mass ratio of gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-o-phenanthroline is 1:0.2) and an organic solvent (18-crown-6 and dichloromethane in a volume ratio of 1:3) are mixed, and the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene and 2,6-di-tert-butylphenol are added. The molar ratio of phenol is 1:6; the mass of the silica-supported phosphotungstic acid is 5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; and the mass of the composite catalyst is 5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene. The reaction is carried out for 36 hours. The resulting product is filtered and the resulting solid is recrystallized with petroleum ether to obtain antioxidant 330 with a yield of 99.1% and a melting point of 239-242°C. Example 3

[0041] The only difference from Example 1 is:

[0042] The 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst (the mass ratio of gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-o-phenanthroline is 1:0.05) and an organic solvent (18-crown-6 and dichloromethane in a volume ratio of 1:3) are mixed, and the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene and 2,6-di-tert-butylphenol are added. The molar ratio of phenol is 1:2; the mass of the silica-supported phosphotungstic acid is 1% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; and the mass of the composite catalyst is 2% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene. The reaction is carried out for 36 hours. The resulting product is filtered and the resulting solid is recrystallized with petroleum ether to obtain antioxidant 330 with a yield of 99.0% and a melting point of 241-244°C.

[0043] Comparative Example 1

[0044] The only difference from Example 1 is that no composite catalyst is added; the yield of the antioxidant 330 obtained in Comparative Example 1 is 80.2%.

[0045] Comparative Example 2

[0046] The only difference from Example 1 is that only gadolinium trifluoromethanesulfonate is added to the composite catalyst; the yield of the antioxidant 330 obtained in Comparative Example 2 is 82.5%.

[0047] Comparative Example 3

[0048] The only difference from Example 1 is that no 18-crown-6 is added to the organic solvent; the yield of the antioxidant 330 obtained in Comparative Example 3 is 81.7%.

[0049] As can be seen from the above embodiments and comparative examples, the present invention can significantly improve the yield of antioxidant 330 by using silica-supported phosphotungstic acid and a composite catalyst to exert a synergistic catalytic effect and simultaneously catalyzing the reaction of 1,3,5-trichloromethyl-2,4,6-trimethylbenzene and 2,6-di-tert-butylphenol in a specific organic solvent to synthesize antioxidant 330.

[0050] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an antioxidant 330, characterized in that: The following steps are involved: 1,3,5-trichloromethyl-2,4,6-trimethylbenzene, 2,6-di-tert-butylphenol, silica-supported phosphotungstic acid, a composite catalyst, and an organic solvent are mixed and reacted to obtain antioxidant 330; The composite catalyst is gadolinium trifluoromethanesulfonate and 3,4,7,8-tetramethyl-1,10-o-phenanthroline in a mass ratio of 1:0.1; The organic solvent is 18-crown-6 and dichloromethane in a volume ratio of 1:

3.

2. The preparation method according to claim 1, wherein The preparation method of 1,3,5-trichloromethyl-2,4,6-trimethylbenzene comprises: mixing a carbon nanotube-supported acid catalyst, mesitylene, 37 wt% concentrated hydrochloric acid and paraformaldehyde, and reacting to obtain 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; the reaction temperature is 35-45° C., and the reaction time is 0.5-1.5 hours.

3. The preparation method according to claim 2, wherein The preparation method of the carbon nanotube-supported acid catalyst comprises: The carbon nanotubes are mixed with concentrated nitric acid and treated with acid to obtain acidified carbon nanotubes; the ethanol suspension of the acidified carbon nanotubes is mixed with tetraisopropyl titanate until it becomes a sol state, and after drying, the obtained dry product is immersed in an acid solution, vacuum dried, and calcined to obtain a carbon nanotube-supported acid catalyst.

4. The preparation method according to claim 1, wherein The preparation method of silica-supported phosphotungstic acid comprises: mixing ultrafine silica and phosphotungstic acid in an aqueous phase, and sequentially performing room temperature impregnation, filtering, drying, and calcining to obtain a silica-supported phosphotungstic acid catalyst; the mass ratio of the ultrafine silica to the phosphotungstic acid is 0.5-5:1; the room temperature impregnation time is 12-36 hours; the drying temperature is 100°C and the time is 2-4 hours; and the calcination temperature is 200°C and the time is 2-5 hours.

5. The preparation method according to claim 1, wherein The molar ratio of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene to 2,6-di-tert-butylphenol is 1:2-6.

6. The preparation method according to claim 1, wherein In terms of mass percentage, the mass of the silica-supported phosphotungstic acid is 1-5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene; and the mass of the composite catalyst is 2-5% of the mass of the 1,3,5-trichloromethyl-2,4,6-trimethylbenzene.

7. The preparation method according to claim 1, wherein The reaction is carried out under reflux conditions; the reaction time is 12 to 36 hours.