WO2023098670A1 - Polyphenol antioxidant and preparation method therefor and application thereof - Google Patents

Abstract

Disclosed are a polyphenol antioxidant and a preparation method therefor and an application thereof. An antioxidant molecule designed in the present invention contains a hindered phenol functional group used as a main antioxidant, and further contains an alcohol amine skeleton unit having a metal ion bonding capability, so that a synergistic antioxidation effect can be achieved during polymer processing and use, and the antioxygen capability of unit mass of the antioxidant molecule is improved. By means of the antioxidant, the problem that a single-function antioxidant has a poor antioxidation effect on a high polymer material is solved, and the antioxygen capability of unit mass of the antioxidant molecule is improved. The preparation method has the advantages of low energy consumption, cheap raw materials, simple operation, easy recycling of materials, recyclable solvent, and high product yield and purity.

Description

A kind of polyphenolic antioxidant and its preparation method and application technical field

The application belongs to the field of chemical auxiliary antioxidant synthesis, and specifically relates to a polyphenol antioxidant and its preparation method and application.

Background technique

With the rapid development of the polymerization industry, various new functional plastics have been developed. These plastics are mainly processed from high molecular polymers. During polymerization, granulation, storage, processing, molding and long-term use, high molecular polymers are susceptible to the effects of light, heat, electric fields, rays, metal ions, chemical reagents, etc., resulting in loss of mechanical properties of polymers, discoloration, Changes such as cracking and loss of gloss are called aging or thermal oxygen aging.

In 1946, Bolland and Gee first proposed that the oxidation of organic lipid chains is a free radical reaction process. In the following years, chemists have conducted extensive mechanistic research on the oxidation process of organic materials, and determined that these complex oxidation processes are accompanied by the generation of by-products (such as: acids, alcohols, aldehydes, ketones, or organic chains with larger molecular weights) ), and these by-products will eventually lead to aging phenomena such as discoloration, cracking, and loss of functionality of plastic products in organic materials. If the alkyl peroxyl radicals generated during the oxidation process are effectively scavenged, the rate of by-product formation will be reduced. Therefore, the addition of antioxidants in production can prevent the oxidation and decomposition of materials, thereby improving the processing stability and long-term use stability of high molecular polymers.

Hindered phenolic antioxidants are the most widely used antioxidants in the field of polymer materials. They have the advantages of good antioxidant effect, high thermal stability, no pollution to products, no coloring, and good compatibility. Monophenolic hindered phenol antioxidants have low relative molecular weight, high volatility and migration loss, resulting in low antioxidant efficiency, and can only be used in high molecular polymers that do not require high performance. Polyphenol-type hindered phenol antioxidants are generally synthesized from monophenol-type hindered phenol structure and other chemical raw materials with specific structures. It has relatively large molecular weight, good extraction resistance, high thermal stability and long-lasting effect. , so it is widely used. Researchers prepared intramolecular composite antioxidants containing phosphorus, nitrogen, silicon, sulfur and heterocyclic structures by changing the skeleton structure of polyphenol-type hindered phenol reaction intermediates. This type of intramolecular composite antioxidant has excellent molecular designability. However, the research and development of new polyphenolic antioxidants is very difficult, and the compatibility, dispersion, migration resistance, volatilization resistance and extraction resistance of antioxidants in polymer materials need to be considered. In addition, in the process of processing high molecular polymers, trace transition metal ions will catalyze and accelerate the oxidation process of lipid chains. Therefore, a new type of antioxidant with large molecular weight, volatile resistance, high thermal stability, high content of effective functional groups per unit mass, long-lasting antioxidant effect, no pollution to products, no coloring, good compatibility and ability to inhibit the catalytic action of metal ions has been developed. agent has become an urgent problem to be solved.

In order to solve the above problems, the applicant has developed a new type of double-effect polyphenolic antioxidant having both polyphenolic hindered phenol and alcohol amine functional groups in structure. This antioxidant not only has the free radical inhibition ability of polyphenol hindered phenol structure, but also has the poisoning ability of alcohol amines to transition metal ions, and can play a synergistic antioxidant effect.

Contents of the invention

In order to meet the increasingly high safety, health and environmental protection requirements of antioxidants in the market, this application designs and develops a new type of star-shaped multifunctional polyphenol antioxidant with high temperature resistance and excellent antioxidation effect, and provides a kind of energy The method for preparing the polyphenolic antioxidant is low in consumption, easy to recycle materials, easy to operate, and high in product yield and purity.

The application provides a compound whose structure is general formula I:

Wherein, R _and R are _{independently} selected from: alkyl, alkoxy, hydroxyalkyl, cycloalkyl, cycloalkylalkyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, Carboxyl, ester, amido, amino, amino, halogen, nitro, cyano, oxycarbonyl, aminocarbonyl;

_R2 is selected from: hydrogen, alkyl, aryl, cycloalkyl.

Further, R ₁ and R ₃ are independently selected from C _1-18 alkyl groups.

Furthermore, R ₁ is C _1-18 alkyl.

Further, R ₃ is C _1-18 alkyl.

Furthermore, at least one of _R1 and _R3 is (or both are) C3-C8 branched chain alkyl, such as isopropyl, tert-butyl, tert-amyl, tert-hexyl, tert-octyl. In one embodiment of the present invention, R ₁ is H or methyl, R ₃ is a branched chain alkyl group of C3-C8; in another embodiment of the present invention, R ₁ and R ₃ are independently selected from C3-C8 A branched alkyl group; for example, R ₁ and R ₃ are both tert-butyl.

Further, R ₂ is selected from C _1-18 alkyl, such as C _1-6 alkyl;

Further, R _is selected from: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl;

In one embodiment of the invention, R ₂ is methyl.

In another embodiment of the invention, _R2 is hydrogen.

Further, the above-mentioned compound may have the following structure:

In an embodiment of the present invention, the above compound has the following structure:

The present application also provides a preparation method of the above-mentioned compound, and the specific steps include:

Step a):

Will

react with an acid halide reagent to give

Step b):

then

Reaction obtains the compound of general formula I;

Wherein, X is a halogen (such as F, Cl, Br, I), especially Cl.

Further, step a) includes:

Disperse in an organic solvent, heat, add acid halide reagent dropwise, and react until complete.

Further, the above-mentioned acid halide reagent can be an acid chloride reagent, for example, thionyl chloride, phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, solid phosgene, phosphorus tribromide, etc., especially dichloride sulfone.

Further, the aforementioned organic solvent may be, for example, benzene, toluene, xylene, acetone, cyclohexanone, dichloromethane, especially xylene.

further,

The molar ratio to the acid halide reagent is 1:2 to 2:1 (eg 1:2, 1:1.5, 1:1.1, 1:1, 1.1:1, 1.5:1, 2:1).

Further, the heating in step a) is heating to 55-65°C (eg 56, 58, 60, 62, 64°C), especially 60°C.

Further, the reaction temperature in step a) is 40-80°C (such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C), especially 50-70°C .

Further, the reaction time in step a) is 1-10h (eg 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h), especially 3-5h.

In one embodiment of the present application, the step a) includes: dispersing the compound represented by formula III (such as 3,5-di-tert-butyl-4-hydroxybenzoic acid) in an organic solvent (such as xylene), Heat to 55-65°C, add acid halide reagent (such as thionyl chloride) dropwise, and keep warm at 50-70°C for 3-5h.

Furthermore, the step a) also includes passing the acidic tail gas into the lye.

Further, the above-mentioned lye is selected from: triethylamine aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution.

Furthermore, in one embodiment of the present application, the lye is 5% sodium hydroxide aqueous solution.

Further, step b) includes: adding alkali to the reaction system of step a), and then adding dropwise

The reaction gives the compound of general formula I.

Further, step b) also includes: cooling the above reaction system to room temperature, adding an aqueous alkali solution, stirring at room temperature (10-60 minutes), and separating the liquids, then washing the organic phase with water, separating the liquids, and evaporating the organic phase solvent under reduced pressure , to obtain the target product (ie, the compound shown in general formula I).

Further, the base in the step b) is selected from: potassium carbonate, sodium carbonate, sodium bicarbonate, pyridine, triethylamine.

Further, the base in the step b) is triethylamine.

Further, in the step b), the feed amount of the reactant is the same as that in the step a).

The molar mass is used as a reference.

Further, in the step b), the alkali and

The molar ratio is 1:1-5:1 (eg 1:1, 1.2:1, 1.5:1, 2:1, 3:1, 4:1, 5:1).

Further, in the step b), the

and

The molar ratio is 1:10-1:1 (such as 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1 :1).

Further, in the step b), the

Selected from: triethanolamine, triisopropanolamine.

Further, in the step b), the reaction temperature is 50-120°C (for example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C).

Further, in the step b), the reaction time is 2-12h (for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h).

Further, in the step b), the aqueous alkali solution is a 5% aqueous sodium hydroxide solution.

Further, in the step b), the vacuum distillation temperature is 20-50° C., and the vacuum degree is -0.1-0.05 MPa.

In one embodiment of the present application, step b) includes: adding alkali to the reaction system of step a), and then adding dropwise

Heat to 50-120°C, keep stirring for 2-12h, then cool to room temperature, add an appropriate amount of alkali aqueous solution, stir at room temperature (10-60 minutes) (remove unreacted compound of formula IV), separate liquid, and then separate the organic phase Wash with water (remove the unreacted compound shown in formula V, the salt formed by the unreacted compound shown in formula V and base, the salt formed by the unreacted compound shown in formula III and base), separate the liquid, and evaporate the organic phase under reduced pressure solvent, and dried to obtain the target product (compound shown in general formula I).

The present invention also provides an application of the above-mentioned compound and its preparation method in antioxidants.

Specifically, the above-mentioned antioxidants can be used for anti-oxidation during the polymerization, granulation, storage, processing, molding and use of polymer materials.

The present invention also provides an application of the above-mentioned compound and its preparation method in the anti-oxidation of polymer materials.

Specifically, the above polymer materials are plastics, such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS), polymethacrylate (PMMA), ethylene-vinyl acetate copolymer (EVA), polyamide (PA), polytetrafluoroethylene (PTFE), etc.

The advantages and positive effects of the application are as follows:

Provided a new star-shaped multifunctional polyphenol antioxidant with high temperature resistance, metal bonding ability and excellent antioxidation effect, which solved the problem of poor antioxidation effect of single functional antioxidant on polymer materials, Improve the anti-oxidation ability of the molecular unit mass of the antioxidant; and also provide a preparation process with low energy consumption, cheap raw materials, simple operation, easy material recovery, recyclable solvent, and high product yield and purity.

The polyphenol antioxidant molecule prepared by this application not only contains the hindered phenol functional group as the main antioxidant, but also contains the alcohol amine skeleton unit with metal ion bonding ability, which can play a role in the processing and use of polymer materials. Synergistic antioxidant effect.

Detailed ways

Unless otherwise defined, all scientific and technical terms used in the present invention have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains.

The term "alkyl" refers to a straight or branched hydrocarbon chain free radical without unsaturated bonds, and the hydrocarbon chain free radical is connected to the rest of the molecule by a single bond. Typical alkyl groups contain from 1 to 18 (eg, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18) carbons Atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, isohexyl wait. If the alkyl group is substituted by cycloalkyl, it corresponds to "cycloalkylalkyl", such as cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl, and the like. If an alkyl group is substituted by an aryl group, it corresponds to an "aralkyl group", such as benzyl, benzhydryl or phenethyl. If an alkyl group is substituted by a heterocyclyl group, it corresponds to a "heterocyclylalkyl".

The term "cycloalkyl" refers to an alicyclic hydrocarbon, such as containing 1 to 4 monocyclic and/or condensed rings, containing 3-18 carbon atoms, preferably 3-10 (eg 3, 4, 5, 6, 7 , 8, 9, 10) carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or adamantyl, etc.

The term "aryl" refers to monocyclic or polycyclic radicals, including polycyclic radicals containing single aryl groups and/or fused aryl groups, such as containing 1-3 single or condensed rings and 6 -18 (such as 6, 8, 10, 12, 14, 16, 18) carbon ring atoms, the C6-C12 aryl group in the present invention refers to an aryl group containing 6-12 carbon ring atoms, such as benzene Base, naphthyl, biphenyl, indenyl, etc.

The term "heterocyclyl" includes heteroaromatic and heteroalicyclic groups containing 1 to 3 monocyclic and/or fused rings and 3 to about 18 ring atoms, the heteroatoms may be selected from N, O or S atom.

The term "halogen" refers to bromine, chlorine, iodine or fluorine.

It should be pointed out that the following detailed description is exemplary and is intended to provide further explanation to the present application. Unless defined otherwise, 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 application belongs.

Example 1: Preparation of 1,1',1"-nitrilotris(3,5-di-tert-butyl-4-hydroxybenzoic acid) tri-2-propanol ester

(a) Preparation of 3,5-di-tert-butyl-4-hydroxybenzoyl chloride

Put 20.0g (80mmol) 3,5-di-tert-butyl-4-hydroxybenzoic acid and 100mL xylene solvent into a 250mL three-necked bottle in turn, stir evenly to make the dispersion well, slowly heat to 60°C, and then slowly add to the reaction system Slowly add 6.4mL (88mmol) of thionyl chloride dropwise, and keep warm at 50-70°C for 3-5h. TLC monitors that the reaction is complete, and a light yellow clear acid chloride xylene solution is obtained. During the reaction, the acidic tail gas was passed into 200mL of 5% aqueous sodium hydroxide solution.

(b) Preparation of 1,1',1"-nitrilotris(3,5-di-tert-butyl-4-hydroxybenzoic acid) tri-2-propanol ester

Add 13.3mL (96mmol) triethylamine to the above-mentioned three-necked flask, then add 4.58g (24mmol) triisopropanolamine solid powder, heat the reaction system to 110°C, keep stirring for 10h, then naturally cool to room temperature, and then transfer to the three-necked flask Add 150mL 5% sodium hydroxide aqueous solution to the bottle, stir at room temperature for 30min, remove unreacted 3,5-di-tert-butyl-4-hydroxybenzoyl chloride; separate the water phase, then add 100mL water to the oil phase, stir 10min, remove excess ammonium salt, triisopropanolamine and sodium 3,5-di-tert-butyl-4-hydroxybenzoate in the oil phase; finally separate the oil phase, evaporate the organic phase xylene solvent under reduced pressure, and obtain the target Antioxidant (white solid, 15.1 g, yield 71%).

NMR and MS characterization of 1,1',1"-nitrilotris(3,5-di-tert-butyl-4-hydroxybenzoic acid)tri-2-propanol ester: white solid; ¹ H NMR (400MHz, CDCl ₃ )δ1.19(m,9H),1.43(s,54H),2.69(m,6H),4.96(m,3H),5.65(s,3H),7.88(s,6H).HRMS(ESI -TOF)calcd for C ₅₄ H ₈₂ NO ₉ ⁺ ([M+H] ⁺ )888.5984,found 888.5989.

Example 2: Preparation of 2,2',2"-nitrilotris(3,5-di-tert-butyl-4-hydroxybenzoic acid) triethanol ester

(a) Preparation of 3,5-di-tert-butyl-4-hydroxybenzoyl chloride

Put 20.0g (80mmol) 3,5-di-tert-butyl-4-hydroxybenzoic acid and 100mL xylene solvent into a 250mL three-necked bottle in turn, stir evenly to make the dispersion well, slowly heat to 60°C, and then slowly add to the reaction system Slowly add 6.4mL (88mmol) of thionyl chloride dropwise, and keep warm at 50-70°C for 3-5h. TLC monitors that the reaction is complete, and a light yellow clear acid chloride xylene solution is obtained. During the reaction, the acidic tail gas was passed into 200mL of 5% aqueous sodium hydroxide solution.

(b) Preparation of 2,2',2"-nitrilotris(3,5-di-tert-butyl-4-hydroxybenzoic acid) triethanol ester

Add 13.3mL (96mmol) triethylamine to the above-mentioned three-necked flask, then dropwise add 3.2mL (24mmol) triethanolamine, heat the reaction system to 100°C, keep stirring for 8 hours, then cool to room temperature naturally, and then add 150mL 5% sodium hydroxide aqueous solution, stirred at room temperature for 30min, removed unreacted 3,5-di-tert-butyl-4-hydroxybenzoyl chloride; separated the water phase, then added 100mL water to the oil phase, stirred for 10min, removed the oil Unnecessary ammonium salt, triethanolamine and 3,5-di-tert-butyl-4-hydroxybenzoic acid sodium in the phase; Finally, the oil phase is separated, and the organic phase xylene solvent is evaporated under reduced pressure to obtain the target antioxidant (white solid, 15.8g, yield 78%).

NMR and MS characterization of 2,2',2"-nitrilotris(3,5-di-tert-butyl-4-hydroxybenzoic acid) triethanol ester: white solid; ¹ H NMR (400MHz, CDCl ₃ )δ1 .42(s,54H),2.82(t,J=7.5Hz,6H),4.12(t,J=7.8Hz,6H),5.65(s,3H),7.89(s,6H).HRMS(ESI- TOF) calcd for C ₅₁ H ₇₅ NNaO ₉ ⁺ ([M+Na] ⁺ )868.5334, found 868.5337.

Example 3

Oxidation induction period test: This test is carried out on the DSC 200 PC thermal analysis device, connect oxygen and nitrogen, turn on the gas switching device to adjust the flow of the two gases respectively, so that they both reach (50±5)ml/min, Then switch to nitrogen. Place the open aluminum dish containing (15±0.5) mg sample on the sample holder of the thermal analyzer, raise the temperature to (200±0.1)°C at a rate of 20°C/min, keep the temperature constant, and start recording thermal curve. After keeping the constant temperature for 5 minutes, switch to oxygen quickly. The test was terminated when a maximum oxidation exotherm was recorded on the thermal curve. See Table 1 for sample composition information, and Table 2 and Table 3 for test results.

Table 1 Sample composition:

serial number	resin	antioxidant	content	light stabilizer	content
1	PE powder	Irganox B215	0.2%	the	the
2	PE powder	the	the	Example 1 product	0.2%
3	PE powder	the	the	Example 2 product	0.2%
4	PP powder	Irganox B225	0.2%	the	the
5	PP powder	the	the	Example 1 product	0.2%
6	PP powder	the	the	Example 2 product	0.2%

Table 2 Oxidation induction period of PE samples

Table 3 Oxidation induction period of PP samples

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (10)

1. A kind of compound, its structure is general formula I:

   

   Wherein, R _and R are _{independently} selected from: alkyl, alkoxy, hydroxyalkyl, cycloalkyl, cycloalkylalkyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, Carboxyl, ester, amido, amino, amino, halogen, nitro, cyano, oxycarbonyl, aminocarbonyl;

   _R2 is selected from: hydrogen, alkyl, aryl, cycloalkyl.
2. The compound of claim 1, wherein said R ₁ and R ₃ are independently selected from C _1-18 alkyl groups.
3. The compound of claim 1, wherein at least one _of R and _R is a C3-C8 branched alkyl group;

   Preferably, at least one of _R1 and _R2 is isopropyl, tert-butyl, tert-amyl, tert-hexyl, tert-octyl.
4. The compound of claim 1, wherein R ₁ and R ₃ are both tert-butyl.
5. The compound according to any one of claims 1-4, wherein R _is selected from: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl.
6. The compound of claim 1, wherein the compound has the following structure:

   
7. A preparation method of the compound described in any one of claims 1-6, comprising the steps of:

   Step a):

   Will

   

   react with an acid halide reagent to give

   

   Step b):

   Will

   

   Reaction obtains the compound of general formula I;

   Wherein, X is a halogen.
8. The preparation method according to claim 7, characterized in that step a) comprises: dispersing the compound shown in formula III in an organic solvent, heating to 55-65°C, adding acid halide reagent dropwise, at 50-70°C Keep warm for 3-5 hours.
9. The preparation method according to claim 7, characterized in that, step b) comprises: adding alkali to the reaction system of step a), and then adding dropwise

   

   Heat to 50-120°C, keep warm and stir for 2-12h, then cool to room temperature, add an appropriate amount of alkali aqueous solution, stir at room temperature, separate the liquids, then wash the organic phase with water, separate the liquids, evaporate the organic phase solvent under reduced pressure, and dry it. obtain the target product.
10. An application of the compound described in any one of claims 1-6 or the preparation method described in claims 7-9 in the anti-oxidation of polymer materials;

    Preferably, the polymer material is plastic.