A process for the continuous production of antioxidant 1010

Abstract

The present application relates to the technical field of antioxidant synthesis, and particularly relates to a method for continuously preparing antioxidant 1010. The method comprises the following steps: (1) mixing beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid methyl ester, pentaerythritol and a solvent to form a mixture A; (2) feeding the mixture A into a reactor filled with a heterogeneous basic catalyst A to obtain a product B; (3) feeding the product B into a reaction kettle, adding a heterogeneous basic catalyst B, and adding beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid methyl ester to obtain a product C; (4) filtering the product C, and then performing cooling crystallization, filtering and washing, and drying to obtain the antioxidant 1010; the heterogeneous basic catalyst A and the heterogeneous basic catalyst B are each independently a molecular sieve loaded with organic tin or a molecular sieve loaded with an ionic liquid. The method can obtain a high raw material conversion rate and a high selectivity of the target product antioxidant 1010.

Description

Technical Field

[0001] This invention relates to the field of antioxidant synthesis technology, and specifically to a method for the continuous preparation of antioxidant 1010. Background Technology

[0002] The Chinese name of antioxidant 1010 is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], which belongs to the high molecular weight hindered phenolic antioxidants. It is widely used in plastic, rubber and coating products to increase the product's resistance to photo- and heat oxidation. With the increasing market demand for plastics, rubber and coatings, the demand for antioxidants that can increase the product's resistance to photo- and heat oxidation is also increasing. As one of the antioxidants, the demand for antioxidant 1010 is also increasing accordingly.

[0003] In existing processes, most reactions are carried out in a reactor using methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol, and a catalyst. These reactions are all batch reactions, which are not only uneconomical but also have poor selectivity for antioxidant 1010. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that the preparation of antioxidant 1010 in the prior art is a batch reaction with low economic efficiency, and to provide a method for the continuous preparation of antioxidant 1010. This method not only enables the continuous synthesis of antioxidant 1010, but also has a high conversion rate of raw materials to the target product antioxidant 1010.

[0005] This invention provides a method for the continuous preparation of antioxidant 1010, the method comprising: (1) Mixture A formed by mixing methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol and solvent; (2) Mixture A enters a reactor filled with heterogeneous alkaline catalyst A to react and obtain product B; (3) Product B flows into the reactor, and heterogeneous alkaline catalyst B is added at the same time, and methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added to react and obtain product C; (4) The filtrate after filtering product C is cooled, crystallized, filtered, washed and dried to obtain antioxidant 1010; The heterogeneous basic catalyst A and the heterogeneous basic catalyst B are each independently a molecular sieve supported on organotin or a molecular sieve supported on ionic liquid.

[0006] Preferably, the method for preparing the organotin-loaded molecular sieve includes: dissolving organotin in ethanol to form a solution with a mass concentration of 20-50 wt%, then adding molecular sieve to the solution, mixing and stirring at 40-50°C for 4-6 hours, placing it in an oven, drying at 80-90°C for 6-10 hours, and finally calcining at 400-500°C for 3-5 hours to obtain the organotin-loaded molecular sieve.

[0007] Preferably, the organotin is selected from at least one of butyltin oxide, dioctyltin oxide, and diphenyltin dichloride.

[0008] Preferably, the method for preparing the molecular sieve loaded with ionic liquid includes: mixing acetonitrile and ethanol in a volume ratio of 1:2-4 to obtain a mixed solvent; adding ionic liquid to the mixed solvent and mixing for 10-30 min; then adding molecular sieve and stirring at room temperature (15-30℃) for 20 h; then refluxing at 78-85℃ for 20-48 h; and finally drying at 80-90℃ under normal pressure for 12-20 h and under vacuum at 50-70℃ for 12-20 h to obtain the molecular sieve loaded with ionic liquid.

[0009] Preferably, the solvent is selected from at least one of tetrahydrofuran, toluene, xylene, diethyl ether, and cyclohexane; the amount of the solvent used is 2-3 times the mass of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0010] Preferably, in step (1), the molar ratio of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to pentaerythritol is (4-4.5):1.

[0011] Preferably, in step (2), the mass hourly space velocity (MHSV) of mixture A is 0.5-3 hr. -1 .

[0012] Preferably, in step (2), the reaction pressure is 0.1-0.5 MPa and the reaction temperature is 160-180℃.

[0013] Preferably, the molar ratio of the β-(3,5-di-tert-4-hydroxyphenyl) lactone methyl ester added in step (3) to the molar ratio of pentaerythritol in step (1) is (0.5-1):1.

[0014] Preferably, the reaction temperature in step (3) is 160-180℃, the reaction time is 2-3h, and the reaction pressure is 0.05~-0.1MPa.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The method of the present invention can continuously prepare antioxidant 1010 and has good economic efficiency; (2) The catalyst in this invention can be recovered through simple filtration and can be recycled; (3) The method of the present invention can achieve a high raw material conversion rate and selectivity of the target product antioxidant 1010; (4) The antioxidant 1010 prepared in this invention has extremely low metal impurities. When used in polyethylene or polypropylene, it can increase its antioxidant properties and will not affect the color of polyethylene or polypropylene products. Attached Figure Description

[0016] Figure 1 The 1H NMR spectrum of antioxidant 1010 prepared in Example 1; Figure 2 The image shows the carbon NMR spectrum of antioxidant 1010 prepared in Example 1. Detailed Implementation

[0017] 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.

[0018] The first aspect of the present invention provides a method for continuously preparing antioxidant 1010, the method comprising: (1) Mixture A formed by mixing methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol and solvent; (2) Mixture A enters a reactor filled with heterogeneous alkaline catalyst A to react and obtain product B; (3) Product B flows into the reactor, and heterogeneous alkaline catalyst B is added at the same time, and methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added to react and obtain product C; (4) The filtrate after filtering product C is cooled, crystallized, filtered, washed and dried to obtain antioxidant 1010; The heterogeneous basic catalyst A and the heterogeneous basic catalyst B are each independently a molecular sieve supported on organotin or a molecular sieve supported on ionic liquid.

[0019] In this invention, antioxidant 1010 can be continuously prepared using the preparation method of this invention. Specifically, after obtaining product B, when product B is fed into a reaction vessel for reaction to prepare product C, the mixture A can begin the preparation of the next batch of product B. The heterogeneous alkaline catalyst A can be directly recycled multiple times, and in this invention, the heterogeneous alkaline catalyst B can be recovered and reused through simple filtration. Both the heterogeneous alkaline catalyst A and the heterogeneous alkaline catalyst B can maintain high catalytic activity, overcoming the shortcomings of the prior art in that homogeneous catalysts are not easy to recover and that the prior art cannot continuously produce antioxidant 1010.

[0020] In a preferred embodiment, the heterogeneous basic catalyst A is a molecular sieve supported on organotin; the heterogeneous basic catalyst B is a molecular sieve supported on an ionic liquid.

[0021] In this invention, the use of organotin-loaded molecular sieves in the first stage reaction and ionic liquid-loaded molecular sieves in the second stage reaction can better increase the conversion rate of raw materials and the selectivity of antioxidant 1010. This is likely because the organotin-loaded molecular sieves in the first stage reaction can better promote the formation of active intermediates, which, in the presence of ionic liquid-loaded molecular sieves, are more readily reacted with the added methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to produce antioxidant 1010.

[0022] In one embodiment, the method for preparing the organotin-loaded molecular sieve includes: dissolving organotin in ethanol to form a solution with a mass concentration of 20-50 wt%; then adding molecular sieve to the solution; mixing and stirring at 40-50°C for 4-6 hours; placing the solution in an oven and drying at 80-90°C for 6-10 hours; and finally calcining at 400-500°C for 3-5 hours to obtain the organotin-loaded molecular sieve.

[0023] In a preferred embodiment, when using a molecular sieve loaded with organotin, the mass ratio of the solution to the molecular sieve is (0.5-1.2):1, for example, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1 or 1.2:1.

[0024] In a more preferred embodiment, when preparing the organotin-loaded molecular sieve, the mass ratio of the solution to the molecular sieve is (0.8-1):1.

[0025] In one embodiment, the organotin is selected from at least one of butyltin oxide, dioctyltin oxide, and diphenyltin chloride, preferably a combination of dioctyltin oxide and diphenyltin chloride, with a weight ratio of 1:(1-2), more preferably 1:1.

[0026] In this invention, the use of specific organotin compounds can better synergize with molecular sieves to increase their catalytic activity, thereby increasing the conversion rate of raw materials.

[0027] In a preferred embodiment, when preparing the organotin-loaded molecular sieve, the molecular sieve is selected from at least one of MCM-41 molecular sieve, Naβ molecular sieve, TS-1 molecular sieve and USY molecular sieve, preferably TS-1 molecular sieve.

[0028] In this invention, the synergistic effect of TS-1 molecular sieve and organotin not only results in better catalytic activity, but also further increases the thermal stability of the catalyst.

[0029] In a preferred embodiment, when preparing the organotin-loaded molecular sieve, the molecular sieve is a spherical molecular sieve with an average particle size of 2-3 mm.

[0030] In a more preferred embodiment, when preparing the organotin-loaded molecular sieve, the molecular sieve is a spherical TS-1 molecular sieve with an average particle size of 2-3 mm.

[0031] In this invention, the molecular sieve can be obtained commercially. In one embodiment, the spherical TS-1 molecular sieve with an average particle size of 2-3 mm is purchased from Zhuoran Environmental Protection Technology (Dalian) Co., Ltd.

[0032] In this invention, organotin and molecular sieve have a certain synergistic effect. The heterogeneous alkaline catalyst A and heterogeneous alkaline catalyst B prepared not only have good catalytic performance when used, but also have good selectivity in the preparation of antioxidant 1010. Furthermore, the catalyst is easy to separate and recover, and can be reused multiple times. Moreover, the molecular sieve loaded with organotin can effectively fix organotin, thereby reducing the content of metal impurities in antioxidant 1010.

[0033] In a preferred embodiment, the method for preparing the molecular sieve loaded with ionic liquid includes: mixing acetonitrile and ethanol in a volume ratio of 1:2-4 to obtain a mixed solvent; adding an ionic liquid to the mixed solvent and mixing for 10-30 min; then adding the molecular sieve and stirring at room temperature (15-30℃) for more than 20 h; then refluxing at 78-85℃ for 20-48 h; and finally drying at 80-90℃ under normal pressure for 12-20 h and under vacuum at 50-70℃ for 12-20 h to obtain the molecular sieve loaded with ionic liquid.

[0034] In a preferred embodiment, when preparing a molecular sieve loaded with an ionic liquid, the ratio of ionic liquid to mixed solvent is 1 g : (150-300) mL.

[0035] In a preferred embodiment, when preparing the molecular sieve loaded with ionic liquid, the mass ratio of ionic liquid to molecular sieve is 0.3-0.5:1, preferably 0.4:1.

[0036] In a preferred embodiment, when preparing the molecular sieve loaded with the ionic liquid, the ionic liquid is selected from at least one of 1-butyl-3-methylimidazolium carboxylate, 1-butyl-3-methylimidazolium acetate, and 1-butyl-3-methylimidazolium propionate, preferably 1-butyl-3-methylimidazolium acetate.

[0037] In a preferred embodiment, when preparing the molecular sieve loaded with ionic liquid, the molecular sieve is selected from at least one of MCM-41 molecular sieve, Naβ molecular sieve, TS-1 molecular sieve and USY molecular sieve, preferably TS-1 molecular sieve.

[0038] In a more preferred embodiment, when preparing the molecular sieve loaded with ionic liquid, the molecular sieve is a spherical TS-1 molecular sieve with an average particle size of 2-3 mm.

[0039] In one embodiment, the solvent is selected from at least one of tetrahydrofuran, toluene, xylene, diethyl ether, and cyclohexane, preferably xylene.

[0040] In this invention, the reaction proceeds more stably in the presence of a solvent, particularly xylene, increasing the conversion rate of the raw materials and the selectivity of antioxidant 1010.

[0041] In one embodiment, in step (1), the molar ratio of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to pentaerythritol is (4-4.5):1, for example, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1 or 4.5:1.

[0042] In this invention, by controlling the molar ratio between raw materials in step (1), the conversion rate of raw materials and the selectivity of antioxidant 1010 can be better increased.

[0043] In one embodiment, in step (1), the amount of solvent used is 2-3 times the mass of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0044] In this invention, the presence of a solvent allows the reaction to proceed more smoothly, resulting in a high conversion rate of pentaerythritol and a high yield of antioxidant 1010.

[0045] There are no special limitations on the mixing in step (1). It can be mixed at room temperature or at a certain temperature. It is preferred to mix at 60-70°C for 10-60 minutes.

[0046] In this invention, under these mixing conditions, it is more favorable for the mixture A to react with the heterogeneous alkaline catalyst A to obtain product B, which is conducive to the stable formation of antioxidant 1010.

[0047] In one embodiment, in step (2), the mass hourly space velocity of mixture A is 0.5-3 hr. -1 For example, 0.5 hr -1 0.8 hr -1 1 hr -1 1.2 hr -1 1.5 hr -1 1.8 hr -1 2 hr -1 2.5 hr -1 2.8 hr -1 Or 3 hours -1 .

[0048] In one preferred embodiment, in step (2), the mass hourly space velocity of mixture A is 1-3 hr. -1 .

[0049] In one embodiment, in step (2), the reaction pressure is 0.1-0.5 MPa, for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa or 0.5 MPa.

[0050] In one embodiment, in step (2), the reaction temperature is 100-130°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or 130°C.

[0051] In this invention, although the organotin-loaded molecular sieve has good catalytic activity, it may affect the tin content in antioxidant 1010. However, the antioxidant 1010 in this invention has an extremely low metallic tin content. The inventors speculate that this is partly because different catalysts are used in the two stages of the reaction, and partly because the reaction conditions of the first stage are strictly controlled. Under these conditions, not only is a high raw material conversion rate obtained, but antioxidant 1010 also has high selectivity and an extremely low tin content. The inventors speculate that product B contains some intermediates, which are more conducive to the subsequent reaction with the added methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and the residual methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate in the presence of heterogeneous alkaline catalyst B, thus reducing the reaction time and avoiding the defects of side reactions that are prone to occur in the later stages of the reaction. At the same time, under these conditions, there is basically no loss of metallic tin.

[0052] In one embodiment, in step (3), the amount of heterogeneous basic catalyst B is 1-3 wt% of the mass of the added β-(3,5-ditert-4-hydroxyphenyl) lactone methyl ester, for example, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, or 3 wt%.

[0053] In this invention, the use of heterogeneous catalyst B enables the better preparation of antioxidant 1010.

[0054] In one embodiment, the molar ratio of the β-(3,5-di-tert-4-hydroxyphenyl) lactone methyl ester added in step (3) to the molar ratio of pentaerythritol in step (1) is (0.5-1):1, for example 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1:1.

[0055] In this invention, the addition of methyl β-(3,5-di-tert-yl-4-hydroxyphenyl) lactone to react with product B in the presence of heterogeneous catalyst B can better increase the conversion rate of raw materials and the selectivity of antioxidant 1010. This may be because the added methyl β-(3,5-di-tert-yl-4-hydroxyphenyl) lactone can further react with unreacted pentaerythritol that may be present in product B, or react with some intermediates in product B to generate antioxidant 1010.

[0056] In one embodiment, the reaction temperature in step (3) is 160-180°C.

[0057] In this invention, by controlling the reaction temperature in step (3), the reaction is directed in a direction that favors the generation of antioxidant 1010.

[0058] In one implementation, the reaction time in step (3) is 2-3 hours.

[0059] In this invention, the time required for batch reaction can be significantly reduced and the selectivity of antioxidant 1010 can be increased, possibly because during this time, the intermediate in product B can further react with the raw materials to produce antioxidant 1010, while the raw materials also further react with each other to generate antioxidant 1010.

[0060] In one embodiment, the reaction pressure in step (3) is 0.05 to -0.1 MPa, for example, 0.05 MPa, 0.04 MPa, 0.03 MPa, 0.02 MPa, 0.01 MPa or -0.1 MPa.

[0061] Under this reaction, some small molecule compounds produced by the reaction can be removed, allowing the reaction to proceed in the direction of generating antioxidant 1010.

[0062] In one embodiment, the method of cooling crystallization in step (4) is not particularly limited, for example, cooling to below 8°C using an ice water bath.

[0063] In one embodiment, in step (4), washing can be performed using ethanol.

[0064] In one embodiment, the drying method in step (4) is not particularly limited and can be a conventional drying method in the art. The present invention will not elaborate on this further.

[0065] The antioxidant 1010 prepared in this invention has extremely low levels of metallic impurities. When used in polyethylene or polypropylene, it can increase their antioxidant properties without affecting the color of the polyethylene or polypropylene products.

[0066] The present invention will be described in detail below through examples. In the following examples and comparative examples, TS-1 molecular sieve (average particle size of 2-3 mm, spherical) was purchased from Zhuoran Environmental Protection Technology (Dalian) Co., Ltd. Unless otherwise specified, other components are conventional commercial products. Preparation Example Preparation of organotin-supported molecules (catalyst A): Dioctyltin oxide and diphenyltin dichloride were dissolved in ethanol at a weight ratio of 1:1 to form a solution with a mass concentration of 35 wt% (250 g). Then, 250 g of TS-1 molecular sieve was added to the solution. The mixture was stirred at 45 °C for 5 h, then placed in an oven and dried at 85 °C for 8 h. Finally, it was calcined at 480 °C for 4 h to obtain the organotin-loaded molecular sieve.

[0067] Preparation of molecular sieves (catalyst B) supported on ionic liquids: 5 L of acetonitrile and 15 L of ethanol were mixed to obtain a mixed solvent. 100 g of 1-butyl-3-methylimidazolium acetate was added to the mixed solvent and mixed for 15 min. Then 250 g of TS-1 molecular sieve was added and stirred at room temperature for 30 h. After that, the mixture was refluxed at 82 °C for 24 h. Finally, the mixture was dried at 85 °C under normal pressure for 12 h and then under vacuum at 60 °C for 18 h to obtain a molecular sieve loaded with ionic liquid. Example 1

[0068] Preparation of Antioxidant 1010: Mixture A is formed by mixing 1230g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 136g of pentaerythritol, and 2700g of xylene at 65°C for 30min. Mixture A (mass hourly space velocity of 1.5 hr) -1The product B is obtained by reacting in a reactor filled with catalyst A (reaction pressure: 0.3 MPa, reaction temperature: 105 °C). Product B flows into the reactor, and 2.6g of catalyst B is added at the same time. 175g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010.

[0069] The 1H NMR spectrum of the prepared antioxidant 1010 is shown below. Figure 1 As shown; The carbon NMR spectrum of the prepared antioxidant 1010 is shown below. Figure 2 As shown.

[0070] Example 2 Preparation of Antioxidant 1010: Mixture A is formed by mixing 1018g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 110g of pentaerythritol and 2550g of xylene at 65°C for 30min. Mixture A (mass hourly space velocity of 1.8 hr) -1 The product B is reacted in a reactor filled with catalyst A to obtain product B (reaction pressure: 0.5 MPa, reaction temperature: 110 °C). Product B flows into the reactor, and catalyst B 3.3g is added at the same time. 165g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010.

[0071] Example 3 Preparation of Antioxidant 1010: Mixture A is formed by mixing 772g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 82g of pentaerythritol and 2240g of xylene at 65℃ for 30min. Mixture A (mass hourly space velocity of 1.8 hr) -1 The product B is reacted in a reactor filled with catalyst A to obtain product B (reaction pressure: 0.5 MPa, reaction temperature: 110 °C). Product B flows into the reactor, and 2.8g of catalyst B is added at the same time. 140g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010. Example 4

[0072] Preparation of Antioxidant 1010: Mixture A is formed by mixing 1230g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 136g of pentaerythritol, and 2700g of xylene at 65°C for 30min. Mixture A (mass hourly space velocity of 1.5 hr) -1 The product B is obtained by reacting in a reactor filled with catalyst A (reaction pressure: 0.3 MPa, reaction temperature: 105 °C). Product B flows into the reactor, and catalyst A 2.6g is added at the same time. 175g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010.

[0073] Example 5 Preparation of Antioxidant 1010: Mixture A is formed by mixing 1230g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 136g of pentaerythritol, and 2700g of xylene at 65°C for 30min. Mixture A (mass hourly space velocity of 1.5 hr) -1 The product B is reacted in a reactor filled with catalyst B to obtain product B (reaction pressure: 0.3 MPa, reaction temperature: 105 °C). Product B flows into the reactor, and 2.6g of catalyst B is added at the same time. 175g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010. Example 6

[0074] Preparation of Antioxidant 1010: Mixture A is formed by mixing 1230g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 136g of pentaerythritol, and 2700g of xylene at 65°C for 30min. Mixture A (mass hourly space velocity of 1.5 hr) -1 The product B is reacted in a reactor filled with catalyst B to obtain product B (reaction pressure: 0.3 MPa, reaction temperature: 160 °C). Product B flows into the reactor, and 2.6g of catalyst B is added at the same time. 175g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010.

[0075] Comparative Example 1 Preparation of Antioxidant 1010: Mixture A is formed by mixing 1230g of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 136g of pentaerythritol, and 2700g of xylene at 65°C for 30min. Mixture A (mass hourly space velocity of 1.5 hr) -1 The product B is obtained by reacting in a reactor filled with catalyst A (reaction pressure: 0.3 MPa, reaction temperature: 105 °C). Product B flows into the reactor, and 2.6g of catalyst B is added at the same time. The reaction is carried out at 170℃ and -0.1MPa for 2h to obtain product C. The filtrate after filtering product C is cooled to below 8°C in an ice-water bath. After the solid has completely precipitated, it is filtered, washed with ethanol, and dried to obtain antioxidant 1010.

[0076] Performance testing 1. The conversion rate of pentaerythritol and the selectivity of antioxidant 1010 were tested in the examples and comparative examples, respectively.

[0077] The conversion rate (%) of pentaerythritol is calculated as follows: (moles of pentaerythritol in feed - moles of pentaerythritol remaining) / moles of pentaerythritol in feed * 100% Selectivity of Antioxidant 1010 (%) = (Number of moles of Antioxidant 1010 produced / Total number of moles of product) * 100% 2. The tin impurity ion content of antioxidant 1010 prepared in the examples and comparative examples was tested by ICP-MS (inductively coupled plasma mass spectrometry), and the results are shown in Table 1.

[0078] Table 1 Example 1 99.2 99.1 13.2 Example 2 99.5 98.6 14.8 Example 3 99.3 98.4 14.2 Example 4 99.8 96.2 86.3 Example 5 97.4 99.3 0 Example 6 99.6 97.2 42.4 Comparative Example 1 90.1 96.2 14.1 Examples 1-6 demonstrate that the method of the present invention can achieve high raw material conversion rates and selectivity for the target product antioxidant 1010.

[0079] 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 continuously preparing antioxidant 1010, characterized in that, The method includes: (1) Mixture A formed by mixing methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol and solvent; (2) Mixture A enters a reactor filled with heterogeneous alkaline catalyst A to react and obtain product B; (3) Product B flows into the reactor, and heterogeneous alkaline catalyst B is added at the same time, and methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is added to react and obtain product C; (4) The filtrate after filtering product C is cooled, crystallized, filtered, washed and dried to obtain antioxidant 1010; The heterogeneous alkaline catalyst A is a molecular sieve supported on organotin, and the heterogeneous alkaline catalyst B is a molecular sieve supported on ionic liquid.

2. The method according to claim 1, characterized in that, The method for preparing the organotin-loaded molecular sieve includes: dissolving organotin in ethanol to form a solution with a mass concentration of 20-50 wt%; then adding molecular sieve to the solution; mixing and stirring at 40-50℃ for 4-6 hours; placing the solution in an oven and drying at 80-90℃ for 6-10 hours; and finally calcining at 400-500℃ for 3-5 hours to obtain the organotin-loaded molecular sieve.

3. The method according to claim 2, characterized in that, The organotin is selected from at least one of dioctyltin oxide and diphenyltin dichloride.

4. The method according to claim 1, characterized in that, The method for preparing the molecular sieve loaded with ionic liquid includes: mixing acetonitrile and ethanol in a volume ratio of 1:2-4 to obtain a mixed solvent; adding ionic liquid to the mixed solvent and mixing for 10-30 min; then adding molecular sieve and stirring at 15-30℃ for 20 h; then refluxing at 78-85℃ for 20-48 h; and finally drying at 80-90℃ under normal pressure for 12-20 h and under vacuum at 50-70℃ for 12-20 h to obtain the molecular sieve loaded with ionic liquid.

5. The method according to claim 1, characterized in that, The solvent is selected from at least one of tetrahydrofuran, toluene, xylene, diethyl ether, and cyclohexane; the amount of the solvent used is 2-3 times the mass of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

6. The method according to claim 1, characterized in that, In step (1), the molar ratio of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to pentaerythritol is (4-4.5):

1.

7. The method according to any one of claims 1-6, characterized in that, In step (2), the mass hourly space velocity (MHV) of mixture A is 0.5-3 h⁻¹. -1 .

8. The method according to any one of claims 1-6, characterized in that, In step (2), the reaction pressure is 0.1-0.5 MPa and the reaction temperature is 160-180℃.

9. The method according to any one of claims 1-6, characterized in that, The molar ratio of the methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate added in step (3) to the molar ratio of pentaerythritol in step (1) is (0.5-1):

1.

10. The method according to any one of claims 1-6, characterized in that, The reaction temperature in step (3) is 160-180℃, the reaction time is 2-3h, and the reaction pressure is 0.05~-0.1MPa.

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