Benzanthrone-based compounds, photoinitiators, polymerization systems and preparation methods thereof

Abstract

The invention discloses a compound based on benzanthrone, a photoinitiator, a polymerization system and a preparation method thereof, and belongs to the field of photocuring technology. The chemical structural formula of the compound based on benzanthrone is as follows: wherein M is a morpholinyl group, a piperidinyl group or R is a methyl group, an ethyl group, a propyl group or a phenyl group. The compound can be used as a photoinitiator, has good compatibility with polyethylene and is conducive to improving the curing efficiency of polyethylene, and does not produce bad odor after light cleavage, which is safer and more environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of photocuring, and in particular to a benzanthrone-based compound, a photoinitiator, a polymerization system and a preparation method thereof. Background Art

[0002] Photoinitiator, also known as photosensitizer or photocuring agent, is a type of compound that can absorb a certain wavelength of energy in the ultraviolet or visible light region, and then produce free radicals, cations, etc. to initiate polymerization, cross-linking and curing of monomers.

[0003] The photoinitiators provided by the related art include cleavage-type photoinitiators and hydrogen abstraction-type photoinitiators, wherein the cleavage-type photoinitiators generate free radicals after absorbing energy and transitioning to an excited state, including benzoin compounds, benzil acetals, acetophenone derivatives, etc. The hydrogen abstraction-type photoinitiators absorb energy and react with hydrogen atom donors in an excited state to generate free radicals by bimolecular action, including benzophenone, anthraquinone, thioxanthone, etc.

[0004] However, when used for cross-linking polyethylene, the above-mentioned photoinitiators provided by the related art have at least the following technical problems: poor compatibility with polyethylene, low curing efficiency, etc. Summary of the invention

[0005] In view of this, the present invention provides a benzanthrone-based compound, a photoinitiator, a polymerization system and a preparation method thereof, which can solve the above technical problems.

[0006] Specifically, the following technical solutions are included:

[0007] In one aspect, a compound based on benzanthrone is provided, and the chemical structural formula of the compound is shown below:

[0008]

[0009] Wherein, M is morpholinyl, piperidinyl or R is methyl, ethyl, propyl or phenyl.

[0010] In another aspect, a photoinitiator is provided, wherein the photoinitiator is the above-mentioned benzanthrone-based compound.

[0011] In yet another aspect, a polymerization system is provided, comprising polyethylene and the above-mentioned photoinitiator.

[0012] On the other hand, a method for preparing a compound based on benzanthrone is also provided, the preparation method comprising:

[0013] In the presence of a first catalyst, allowing benzanthrone and p-chlorobenzoyl chloride to react at a first set temperature to obtain an intermediate;

[0014] In the presence of a second catalyst, reacting the intermediate with an amine compound at a second set temperature to obtain the benzanthrone compound;

[0015] Wherein, the amine compound is morpholine, piperidine or R is methyl, ethyl, propyl or phenyl.

[0016] In some possible implementations, the first set temperature is 35°C-45°C.

[0017] In some possible implementations, the first catalyst includes a Lewis acid.

[0018] In some possible implementations, the molar ratio of the p-chlorobenzoyl chloride, the benzothrone and the first catalyst is 1-1.2:1:2-2.2.

[0019] In some possible implementations, the second set temperature is 75°C-110°C.

[0020] In some possible implementations, the second catalyst includes a main catalyst and an auxiliary agent;

[0021] The main catalyst comprises at least one of palladium acetate, tetrakis(triphenylphosphine)palladium, and Pd(pddf)Cl2;

[0022] The auxiliary agent is a phosphorus ligand.

[0023] In some possible implementations, the molar ratio of the intermediate, the amine compound, the main catalyst and the auxiliary agent is 1:1-1.2:0.001-0.1:0.001-0.1.

[0024] In some possible implementations, the intermediate is reacted with the amine compound under an inert and alkaline environment.

[0025] In some possible implementations, the alkaline environment is provided by at least one of the following bases: cesium carbonate, sodium carbonate, potassium carbonate, sodium acetate, sodium tert-butoxide, potassium tert-butoxide.

[0026] In some possible implementations, the molar ratio of the intermediate to the base is 1:0.5-3.

[0027] The beneficial effects of the technical solution provided by the embodiment of the present invention include at least:

[0028] The compound based on benzanthrone provided in an embodiment of the present invention introduces a benzophenone group and a tertiary amine group into benzanthrone, and the compound can be used as a photoinitiator. Among them, the access of the benzophenone group is conducive to improving the compatibility of the compound with polyethylene, and is conducive to reducing the mobility of the compound in a polymerization system containing polyethylene, which is conducive to improving the curing efficiency of polyethylene. In addition, the access of the tertiary amine group can avoid the generation of bad odor after the compound is photolyzed as a photoinitiator, making the compound safer and more environmentally friendly when used as a photoinitiator. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 is the H-NMR spectrum of the intermediate obtained in Example 1 of the present invention;

[0031] Figure 2 is the H-NMR spectrum of the benzanthrone-based compound obtained in Example 2 of the present invention;

[0032] Figure 3 is the H-NMR spectrum of the benzanthrone-based compound obtained in Example 3 of the present invention;

[0033] Figure 4 is the H-NMR spectrum of the benzanthrone-based compound obtained in Example 4 of the present invention;

[0034] Figure 5 is the H-NMR spectrum of the benzanthrone-based compound obtained in Example 5 of the present invention;

[0035] Figure 6 It is the H-NMR nuclear magnetic spectrum of the benzanthrone-based compound obtained in Example 6 of the present invention.

[0036] Among them, for Figure 1-Figure 6 The horizontal axis in the graph is in f1 (ppm), the scale of each space is 1, the starting point from left to right is 15, and the ending point is -3. Figure 1 and Figure 5 The vertical coordinate, each space ruler is 500, the starting point from bottom to top is -500, and the end point is 6500; Figure 2 The vertical coordinate, each space ruler is 1000, the starting point from bottom to top is -1000, and the end point is 11000; Figure 3 and Figure 4The vertical coordinate, each space ruler is 500, the starting point from bottom to top is -500, and the end point is 7500; Figure 6 The vertical coordinate of each space ruler is 500, the starting point from bottom to top is -500, and the end point is 8000. DETAILED DESCRIPTION

[0037] In order to make the technical solutions and advantages of the present application more clear, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0038] For the cross-linking and curing of polyethylene, the photoinitiators commonly used at present include but are not limited to: benzoin compounds, benzyl acetals, acetophenone derivatives, benzophenone, anthraquinone, thioxanthone, etc. However, the above-mentioned various types of photoinitiators have poor compatibility with polyethylene and can only be physically mixed by stirring, etc., and it is difficult to achieve uniform dispersion, which greatly affects the initiation efficiency of the initiator, making the curing and cross-linking efficiency of polyethylene low, thereby affecting the performance of the cross-linked product. In order to improve the initiation efficiency of the photoinitiator and further improve the curing efficiency of polyethylene, the related art usually adds a tertiary amine compound as a co-initiator-hydrogen donor to the polymerization system, such as aliphatic tertiary amines, ethanolamine tertiary amines, tertiary amine type benzoic acid esters, active amines (tertiary amines with acryloxy groups that can participate in polymerization and cross-linking), etc. Tertiary amine compounds are easy to migrate and volatilize during the initiation process, which will produce a large unpleasant odor.

[0039] According to one aspect of an embodiment of the present invention, an embodiment of the present invention provides a compound based on benzanthrone, and the chemical structural formula of the compound based on benzanthrone is as follows:

[0040]

[0041] Wherein, M is morpholinyl, piperidinyl or R is methyl, ethyl, propyl or phenyl.

[0042] When M is a morpholine group, the chemical structural formula of the benzanthrone-based compound is as follows:

[0043]

[0044] When M is a piperidine group, the chemical structural formula of the benzanthrone-based compound is as follows:

[0045]

[0046] When M is When the chemical structure of the benzanthrone-based compound is as follows:

[0047]

[0048] The compound based on benzanthrone provided in an embodiment of the present invention introduces a benzophenone group and a tertiary amine group into benzanthrone, and the compound can be used as a photoinitiator. Among them, the access of the benzophenone group is conducive to improving the compatibility of the compound with polyethylene, and is conducive to reducing the mobility of the compound in a polymerization system containing polyethylene, which is conducive to improving the curing efficiency of polyethylene. In addition, the access of the tertiary amine group can avoid the generation of bad odor after the compound is photolyzed as a photoinitiator, making the compound safer and more environmentally friendly when used as a photoinitiator.

[0049] According to another aspect of the embodiments of the present invention, the embodiments of the present invention provide a photoinitiator, which is the above-mentioned benzanthrone-based compound.

[0050] The benzanthrone-based compound provided in an embodiment of the present invention can be used as a photoinitiator and is particularly suitable for cross-linking and curing of polyethylene, and has at least the following advantages: good compatibility with polyethylene, high curing efficiency, no bad odor, etc.

[0051] According to another aspect of the embodiments of the present invention, the embodiments of the present invention further provide a polymerization system, which includes polyethylene and the photoinitiator provided by the embodiments of the present invention.

[0052] The polymerization system can be used to form a polyethylene cured coating. Furthermore, the polymerization system may also include a resin oligomer and additives. For example, the additives include but are not limited to a leveling agent, a defoaming agent, a dispersant, a color powder, and the like.

[0053] In some examples, the mass ratio of polyethylene to photoinitiator is 1:0.001-0.1, for example, 1:0.001, 1:0.002, 1:0.003, 1:0.005, 1:0.008, 1:0.01, 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, etc.

[0054] According to another aspect of the embodiments of the present invention, the embodiments of the present invention further provide a method for preparing a compound based on benzanthrone, the preparation method comprising:

[0055] S1. In the presence of a first catalyst, react benzothrone with p-chlorobenzoyl chloride at a first set temperature to obtain an intermediate.

[0056] The reaction process involved in S1 can be seen in the following chemical equation:

[0057]

[0058] S2. In the presence of a second catalyst, react the intermediate with an amine compound at a second set temperature to obtain a benzanthrone compound.

[0059] The reaction process involved in S2 can be seen in the following chemical equation:

[0060]

[0061] Wherein the amine compound is morpholine, piperidine or R is methyl, ethyl, propyl or phenyl. In the above chemical formula, the amine compound is To express.

[0062] The preparation method of the compound based on benzanthrone provided in the embodiment of the present invention is to obtain an intermediate including both benzanthrone and benzophenone groups by subjecting benzanthrone to a Friedel-Crafts reaction with p-chlorobenzoyl chloride, and to react the intermediate with an amine compound to connect the tertiary amine group to form the desired benzanthrone-based compound in the embodiment of the present invention. The raw materials used in the preparation method are cheap and readily available, and the reaction conditions are mild, controllable and easy to implement, so that the compound based on benzanthrone is easy to prepare in large-scale production.

[0063] The preparation methods of benzanthrone compounds in the related art use expensive raw materials and relatively harsh reaction conditions, making it difficult to apply them on a large scale. The preparation method of the benzanthrone-based compound provided in the embodiment of the present invention effectively overcomes the above-mentioned shortcomings of the related art.

[0064] The following is an exemplary description of the specific operation methods of the above steps:

[0065] For S1, in some examples, the first catalyst is present, and benzanthrone is reacted with p-chlorobenzoyl chloride at a first set temperature to obtain an intermediate, comprising:

[0066] S11, mixing benzanthrone, p-chlorobenzoyl chloride, a first catalyst, and a first solvent uniformly to form a first reaction system.

[0067] S12, heating the first reaction system to a first set temperature for reaction, and reacting for a first set time to obtain a first product system.

[0068] S13, separating and purifying the first product system to obtain an intermediate. This may include, for example:

[0069] S131, cooling the first product system to room temperature, slowly pouring it into ice water, stirring it and standing it for stratification to obtain an aqueous phase and a first organic phase, wherein the volume ratio of the first solvent to the ice water is 1-2:1.

[0070] S132, extracting the aqueous phase with dichloromethane to obtain an extraction product, and drying the extraction product with the first organic phase (using a desiccant) to obtain a dried product. Exemplarily, the desiccant is at least one of anhydrous sodium sulfate, anhydrous magnesium sulfate, and anhydrous calcium chloride, and the mass ratio of the desiccant to the first solvent is 1:5-10, for example, 1:6, 1:7, 1:8, etc.

[0071] S133, purifying the dried product to obtain an intermediate. For S133, purifying the dried product includes:

[0072] S1331. The dried product is subjected to reduced pressure distillation to obtain a crude intermediate product. S1332. The crude intermediate product is mixed with ethanol and heated to 75°C-80°C, and refluxed for 4h-6h (illustratively, the mass ratio of ethanol to the crude intermediate product is 2-5:1, so that the crude intermediate product is dissolved in ethanol). S1333. The refluxed product is cooled to room temperature, filtered and dried in sequence to obtain an intermediate.

[0073] In some examples, the first set temperature is 35°C-45°C, for example, including but not limited to: 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, etc. The reaction of benzanthrone and p-chlorobenzoyl chloride within the first set temperature range not only has a high reaction rate, but also makes the reaction mild, safe and highly controllable.

[0074] In some examples, the first set time is 4h-8h, for example, 4h, 5h, 6h, 7h, 8h, etc., during which time period it can be ensured that the benzanthrone and p-chlorobenzoyl chloride react completely without excessive reaction.

[0075] In some examples, the first catalyst used includes a Lewis acid, and further an aluminum salt, such as aluminum trichloride, to obtain a high reaction rate.

[0076] In some examples, the first solvent used includes dichloromethane, dichloroethane, and the like.

[0077] In some examples, the molar ratio of p-chlorobenzoyl chloride, benzothrone and the first catalyst is 1-1.2:1:2-2.2, for example, 1:1:2, 1:1:2.2, 1.1:1:2, 1.1:1:2.1, 1.2:1:2, 1.2:1:2.1, 1.2:1:2.2, and the like.

[0078] The mass ratio of the first solvent to benzothrone is 5-10:1, for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0079] For S2, in the presence of a second catalyst, the intermediate and the amine compound are reacted at a second set temperature. In some examples, the second set temperature is 75°C-110°C, such as 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, etc. The reaction of the intermediate and the amine compound within the above temperature range not only has a high reaction rate, but also makes the reaction milder, safer, and more controllable.

[0080] In some examples, the second catalyst includes a main catalyst and an auxiliary agent, wherein the main catalyst includes at least one of palladium acetate, tetrakis(triphenylphosphine)palladium, and Pd(pddf)Cl2; and the auxiliary agent is a phosphorus ligand.

[0081] Illustratively, the phosphorus ligand includes, but is not limited to, triphenylphosphine, tri-tert-butylphosphine, and the like.

[0082] By making the above-mentioned various types of main catalysts and phosphorus ligands work synergistically, the reaction rate of the intermediate and the amine compound can be significantly improved.

[0083] In some examples, the molar ratio of the intermediate, the amine compound, the main catalyst and the auxiliary agent is 1:1-1.2:0.001-0.1:0.001-0.1, so as to achieve the effect of optimizing the above reaction process.

[0084] Furthermore, the intermediate is reacted with the amine compound in an inert and alkaline environment. The inert environment is provided to make the reaction safer and improve the yield, and the alkaline environment is provided to ensure that the reaction proceeds smoothly.

[0085] In some examples, the inert environment is provided by an inert gas, such as nitrogen, argon, or the like.

[0086] In some examples, the alkaline environment is provided by at least one of the following bases: cesium carbonate, sodium carbonate, potassium carbonate, sodium acetate, sodium tert-butoxide, potassium tert-butoxide.

[0087] In some examples, the molar ratio of the intermediate to the base is 1:0.5-3, for example, this includes but is not limited to 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc.

[0088] In some examples, step S2 may include the following steps:

[0089] S21, the intermediate, the amine compound and the second solvent are mixed uniformly to obtain a second reaction system, and then the second reaction system is replaced by an inert gas. The inert gas is replaced multiple times, for example, 3 times or more, to ensure that the second reaction system is in a completely inert environment.

[0090] The second solvent used includes but is not limited to at least one of toluene, o-xylene, m-xylene and p-xylene. The mass ratio of the second solvent to the intermediate is 4-8:1.

[0091] S22, adding a base, a primary catalyst and an auxiliary agent to the second reaction system in an inert environment to obtain a third reaction system, and heating the third reaction system to a second set temperature in an alkaline environment to react to obtain a second product system. Wherein, the reaction can be tracked by thin layer chromatography (Thin Layer Chromatography, TLC) or high performance liquid chromatography (High Performance Liquid Chromatography, HPLC) to ensure that the reaction is complete.

[0092] S23, separating and purifying the second product system to obtain a compound of benzanthrone. This may include, for example:

[0093] S231. Add water to the second product system, stir evenly, and then stand to separate into layers to obtain a second organic phase.

[0094] S232, sequentially subjecting the second organic phase to an activated carbon decolorization treatment and a reduced pressure distillation treatment to obtain a crude product.

[0095] S233, mixing the crude product with ethanol and heating to 75°C-80°C, reflux for 4h-6h (exemplarily, the mass ratio of ethanol to the crude intermediate product is 2-5:1), then cooling the refluxed product to room temperature, filtering and drying in sequence to obtain a benzanthrone-based compound.

[0096] Some specific embodiments of the present invention will be described in more detail below. Although the specific embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the embodiment, those without specifying specific techniques or conditions are carried out according to the techniques or conditions described in the document in this area or according to the product specification. Those without specifying the manufacturer of reagents used or instruments are conventional products that can be obtained by commercial purchase.

[0097] Example 1

[0098] In this Example 1, an intermediate was prepared, and the operation steps are as follows:

[0099] (1) 230 g of benzanthrone, 175 g of p-chlorobenzoyl chloride, 267 g of aluminum chloride, and 100 ml of dichloromethane are mixed uniformly to form a first reaction system. The first reaction system is heated to 40° C. for reaction for 6 hours to obtain a first product system. The first product system is cooled to room temperature, slowly poured into ice water, stirred, and allowed to stand for stratification to obtain an aqueous phase and a first organic phase. The aqueous phase is extracted with dichloromethane to obtain an extraction product, and the extraction product is mixed with the first organic phase and dried over anhydrous sodium sulfate to obtain a dry product.

[0100] (2) The dried product was subjected to reduced pressure distillation at 40°C in a water bath to remove dichloromethane to obtain a crude intermediate product. The crude intermediate product was mixed with 1000 mL of ethanol and heated to 80°C and refluxed for 5 hours. The refluxed product was cooled to room temperature, filtered and dried in sequence to obtain an intermediate.

[0101] The intermediate was characterized by hydrogen nuclear magnetic resonance (H-NMR) test, and the obtained spectrum is shown in Figure 1 ,Depend on Figure 1 It can be seen that the intermediate obtained in Example 1 satisfies the chemical structural formula shown below:

[0102]

[0103] Example 2

[0104] This Example 2 is based on the intermediate provided in Example 1 to prepare a compound based on benzanthrone, and its synthesis reaction equation and preparation steps are as follows:

[0105]

[0106] (1) 184.5 g of the intermediate, 37 g of diethylamine and 1000 mL of toluene were mixed uniformly to obtain a second reaction system, and then the second reaction system was replaced with argon three times.

[0107] (2) 48 g of sodium tert-butoxide, 0.7 g of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and 0.3 g of triphenylphosphine are added to the second reaction system in an inert environment to obtain a third reaction system, and the third reaction system is heated to 80° C. in an alkaline environment for stirring and reaction to obtain a second product system. The reaction can be tracked by TLC or HPLC to ensure that the reaction is complete.

[0108] (3) Add water to the second product system, stir evenly and then stand to separate layers to obtain a second organic phase. The second organic phase is sequentially subjected to activated carbon decolorization and vacuum distillation to obtain a crude product. The crude product is mixed with 1000 mL of ethanol and heated to 80° C., refluxed for 6 h, and then the refluxed product is cooled to room temperature, filtered and dried in sequence to obtain a compound based on benzanthrone.

[0109] The H-NMR characterization test of the benzanthrone-based compound was performed, and the spectrum obtained is shown in Figure 2 ,Depend on Figure 2 It can be seen that the benzanthrone-based compound obtained in Example 2 satisfies the above-mentioned chemical structure.

[0110] Example 3

[0111] This Example 3 is based on the intermediate provided in Example 1 to prepare a compound based on benzanthrone, and its synthesis reaction equation and preparation steps are as follows:

[0112]

[0113] (1) 184.5 g of the intermediate, 50.5 g of dipropylamine and 1000 mL of toluene were mixed uniformly to obtain a second reaction system, and then the second reaction system was replaced with argon three times.

[0114] (2) 48 g of sodium tert-butoxide, 0.7 g of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and 0.3 g of triphenylphosphine are added to the second reaction system in an inert environment to obtain a third reaction system, and the third reaction system is heated to 85° C. in an alkaline environment for stirring and reaction to obtain a second product system. The reaction can be tracked by TLC or HPLC to ensure that the reaction is complete.

[0115] (3) Add water to the second product system, stir evenly and then stand to separate layers to obtain a second organic phase. The second organic phase is sequentially subjected to activated carbon decolorization and vacuum distillation to obtain a crude product. The crude product is mixed with 1000 mL of ethanol and heated to 80° C., refluxed for 5 h, and then the refluxed product is cooled to room temperature, filtered and dried in sequence to obtain a compound based on benzanthrone.

[0116] The H-NMR characterization test of the benzanthrone-based compound was performed, and the spectrum obtained is shown in Figure 3 ,Depend on Figure 3 It can be seen that the benzanthrone-based compound obtained in Example 3 satisfies the above-mentioned chemical structure.

[0117] Example 4

[0118] This Example 4 is based on the intermediate provided in Example 1 to prepare a compound based on benzanthrone, and its synthesis reaction equation and preparation steps are as follows:

[0119]

[0120] (1) 184.5 g of the intermediate, 42.5 g of piperidine and 1000 mL of toluene were mixed uniformly to obtain a second reaction system, and then the second reaction system was replaced with argon three times.

[0121] (2) 48 g of sodium tert-butoxide, 0.7 g of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and 0.3 g of triphenylphosphine are added to the second reaction system in an inert environment to obtain a third reaction system, and the third reaction system is heated to 90° C. in an alkaline environment for stirring and reaction to obtain a second product system. The reaction can be tracked by TLC or HPLC to ensure that the reaction is complete.

[0122] (3) Add water to the second product system, stir evenly and then stand to separate layers to obtain a second organic phase. The second organic phase is sequentially subjected to activated carbon decolorization and vacuum distillation to obtain a crude product. The crude product is mixed with 1000 mL of ethanol and heated to 80° C., refluxed for 4 hours, and then the refluxed product is cooled to room temperature, filtered and dried in sequence to obtain a compound based on benzanthrone.

[0123] The H-NMR characterization test of the benzanthrone-based compound was performed, and the spectrum obtained is shown in Figure 4 ,Depend on Figure 4 It can be seen that the benzanthrone-based compound obtained in Example 4 satisfies the above-mentioned chemical structure.

[0124] Example 5

[0125] This Example 5 is based on the intermediate provided in Example 1 to prepare a compound based on benzanthrone, and its synthesis reaction equation and preparation steps are as follows:

[0126]

[0127] (1) 184.5 g of the intermediate, 43.5 g of morpholine and 1000 mL of toluene were mixed uniformly to obtain a second reaction system, and then the second reaction system was replaced with argon three times.

[0128] (2) 48 g of sodium tert-butoxide, 0.7 g of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and 0.3 g of triphenylphosphine are added to the second reaction system in an inert environment to obtain a third reaction system, and the third reaction system is heated to 90° C. in an alkaline environment for stirring and reaction to obtain a second product system. The reaction can be tracked by TLC or HPLC to ensure that the reaction is complete.

[0129] (3) Add water to the second product system, stir evenly and then stand to separate layers to obtain a second organic phase. The second organic phase is sequentially subjected to activated carbon decolorization and reduced pressure distillation to obtain a crude product. The crude product is mixed with 1000 mL of ethanol and heated to 78° C., refluxed for 5 h, and then the refluxed product is cooled to room temperature, filtered and dried in sequence to obtain a compound based on benzanthrone.

[0130] The H-NMR characterization test of the benzanthrone-based compound was performed, and the spectrum obtained is shown in Figure 5 ,Depend on Figure 5 It can be seen that the benzanthrone-based compound obtained in Example 5 satisfies the above-mentioned chemical structure.

[0131] Example 6

[0132] This Example 6 is based on the intermediate provided in Example 1 to prepare a compound based on benzanthrone, and its synthesis reaction equation and preparation steps are as follows:

[0133]

[0134] (1) 184.5 g of the intermediate, 74.5 g of diphenylamine and 1000 mL of toluene were mixed uniformly to obtain a second reaction system, and then the second reaction system was replaced with argon three times.

[0135] (2) 48 g of sodium tert-butoxide, 0.7 g of [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and 0.3 g of triphenylphosphine are added to the second reaction system in an inert environment to obtain a third reaction system, and the third reaction system is heated to 78° C. in an alkaline environment for stirring and reaction to obtain a second product system. The reaction can be tracked by TLC or HPLC to ensure that the reaction is complete.

[0136] (3) Add water to the second product system, stir evenly and then stand to separate layers to obtain a second organic phase. The second organic phase is sequentially subjected to activated carbon decolorization and vacuum distillation to obtain a crude product. The crude product is mixed with 1000 mL of ethanol and heated to 80° C., refluxed for 5 h, and then the refluxed product is cooled to room temperature, filtered and dried in sequence to obtain a compound based on benzanthrone.

[0137] The H-NMR characterization test of the benzanthrone-based compound was performed, and the spectrum obtained is shown in Figure 6 ,Depend on Figure 6 It can be seen that the benzanthrone-based compound obtained in Example 6 satisfies the above-mentioned chemical structure.

[0138] Comparative Example

[0139] Benzophenone was used as comparative example 1, 3-butoxybenzothrone was used as comparative example 2, and a mixture of 3-butoxybenzothrone and diphenylamine in equal molar amounts was used as comparative example 3.

[0140] Among them, the chemical structure of 3-butoxybenzanthrone is as follows:

[0141]

[0142] Test Case

[0143] In this test example, the compounds provided in Examples 2-6 and Comparative Examples 1-3 were used as photoinitiators, and the modification and crosslinking ability of these photoinitiators on polyethylene was tested, as shown below:

[0144] Test method:

[0145] (1) Preparation of polyethylene polymerization system:

[0146] One part by weight of the photoinitiator sample of the embodiment is mixed with 99 parts by weight of polyethylene to obtain a first mixed material.

[0147] Alternatively, 1 part by weight of the photoinitiator sample of the comparative example, 1 part by weight of the tertiary amine active amine and 98 parts by weight of polyethylene are mixed to obtain a second mixed material.

[0148] The first mixed material and the second mixed material were respectively mixed and passed through an extruder, and hot pressed into 1 mm sheets using a flat vulcanizer at 150° C., thereby preparing a plurality of first polyethylene sample sheets and a plurality of second polyethylene sample sheets.

[0149] The first polyethylene sample and the second polyethylene sample were placed in an ultraviolet radiation device for molten state irradiation for 10 seconds, respectively, and the ultraviolet light source power was 2 kW, thereby obtaining a first photo-crosslinked polyethylene sample and a second photo-crosslinked polyethylene sample.

[0150] (2) Gel content test:

[0151] The above-mentioned photo-crosslinked polyethylene samples were extracted in slightly boiling xylene for 48 hours, and fresh xylene was replaced every 24 hours. Then, the samples were washed with acetone and dried under vacuum at 75°C until constant weight was reached. The gel weight of the photo-crosslinked polyethylene samples was calculated, and the curing efficiency was characterized by the gel content. The gel content (Gel%) was calculated by the following formula:

[0152] Gel%=(W / W0)×100%

[0153] Wherein, W0-sample weight before extraction; W-dry gel weight after extraction;

[0154] Three parallel samples were made for each photo-crosslinked polyethylene sample, and the average value was taken as the gel content value of the sample, which directly characterized the curing efficiency.

[0155] (3) Thermal aging test:

[0156] The above-mentioned photo-crosslinked polyethylene samples were placed in a heat aging box at 158° C. for 168 hours, and then the tensile strength and elongation at break of each photo-crosslinked polyethylene sample were measured.

[0157] Tensile strength determination: The test was conducted in accordance with GB / T 1040-2006. The thickness of the sample was 1.0±0.1mm, the tensile rate was 200±50mm / min, and a Shimadzu DCS-5000 universal tensile testing machine was used. Five parallel samples were made for each sample and the average value was taken.

[0158] Elongation at break: Tested in accordance with GB / T 6344-2008.

[0159] (4) Odor test:

[0160] Each photo-crosslinked polyethylene sample prepared in (1) is placed in a sealed odorless bottle and sealed at room temperature for 2 hours. Then, a tester conducts an odor evaluation according to the evaluation level and records the evaluation results. The evaluation levels include: no odor, slight odor, odor but not irritating, and irritating odor.

[0161] (5) Thermal migration test:

[0162] The first polyethylene sample and the second polyethylene sample were placed in a 75°C oven, and the samples were taken out every 30 minutes. The surface of the samples was wiped with acetone cotton, and the weight was weighed after 2 hours. The reduced weight was the weight of the migrated photoinitiator. After 24 hours, each polyethylene sample was taken out and cross-linked by ultraviolet light, and then the gel content formed by the cross-linking reaction of each sample after the migration of the photoinitiator was measured.

[0163] Test results:

[0164] The test results of curing efficiency are shown in Table 1:

[0165] Table 1

[0166] Samples Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Gel content 49％ 60％ 62％ 63％ 66％ 64％

[0167] As shown in Table 1, the gel content of the cross-linked product corresponding to benzophenone in Comparative Example 1 is 49%, and the gel content of the cross-linked product corresponding to the photoinitiator provided in Examples 2-6 is significantly improved compared with benzophenone, which can reach more than 60%. In particular, the gel content of the photoinitiator corresponding to Example 5 reaches more than 65%. Since the gel content characterizes the degree of cross-linking of double bonds under the same photocuring conditions, and thus reflects the effect of the photoinitiator on the curing efficiency, the higher the gel content, the higher the degree of cross-linking of double bonds, and the higher the curing efficiency. As shown in Table 1, when the compound based on benzanthrone provided in the embodiment of the present invention is used as a photoinitiator, the curing efficiency of polyethylene is higher and has stronger cross-linking performance.

[0168] The test results of the heat aging test and the odor test are shown in Table 2:

[0169] Table 2

[0170]

[0171] Among them, the retention rate of tensile strength (%) = tensile strength after aging / tensile strength before aging; the retention rate of elongation at break (%) = elongation at break after aging / elongation at break before aging.

[0172] As can be seen from Table 2, the photoinitiators provided in Examples 2 to 6 and Comparative Examples 2 to 3 have significantly improved retention rates of tensile strength and elongation at break relative to benzophenone, which indicates that the compounds based on benzanthrone prepared in the embodiments of the present invention have good compatibility with polyethylene when used as photoinitiators, and can better promote the degree of direct bonding of polyethylene polymers, thereby improving the tensile strength of polyethylene polymer products. It can be seen that in the embodiments of the present invention, due to the introduction of benzophenone groups and tertiary amine groups into benzanthrone, the compatibility of these photoinitiator molecules with polyethylene molecules is significantly improved, so that they can be evenly dispersed in polyethylene, and their cross-linking ability is more fully exerted.

[0173] However, other photoinitiators in the prior art cannot be evenly dispersed due to their poor compatibility with polyethylene and can only exist in the form of physical mixing, which greatly restricts their cross-linking ability.

[0174] In addition, the photoinitiators provided in Examples 2-6 produce no odor after photolysis, thus being safer and more environmentally friendly.

[0175] The test results of the thermal migration test are shown in Table 3:

[0176] Among them, the thermal migration weight ratio in Table 3 refers to the ratio of the weight of the migrated photoinitiator to the initial weight of the polyethylene sample; the gel content of cross-linking after migration refers to the ratio of the gel content formed after the cross-linking reaction of each sample after the migration of the photoinitiator to the initial weight of the polyethylene sample.

[0177] Table 3

[0178]

[0179] As can be seen from Table 3, the benzophenone provided by Comparative Example 1 has the fastest migration rate and the largest migration amount in the polymerization system, which seriously affects its cross-linking ability.

[0180] The mobility of 3-butoxybenzanthrone provided in Comparative Example 2 is better than that of benzophenone, but it also affects its cross-linking ability.

[0181] When 3-butoxybenzanthrone is used together with diphenylamine in Example 6, although the migration amount will also increase, the cross-linking ability is better than that of using 3-butoxybenzanthrone alone due to the coordination effect of the active amine.

[0182] The photoinitiator provided in Examples 2-6 has better compatibility in the polyethylene polymerization system and significantly reduces its migration amount after introducing benzophenone groups and tertiary amine groups into the benzanthrone structure. At the same time, its cross-linking ability is less affected by thermal migration and has relatively better cross-linking ability.

[0183] In the embodiments of the present invention, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0184] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A compound based on benzanthrone, characterized in that, The chemical structural formula of the compound is shown below: ； Wherein, M is morpholin-4-yl, piperidin-1-yl, diethylamino, dipropylamino or diphenylamino.

2. A photoinitiator, characterized in that The photoinitiator is the benzanthrone-based compound according to claim 1.

3. A polymerization system, characterized in that The polymerization system comprises polyethylene and the photoinitiator according to claim 2.

4. A method for preparing a compound based on benzanthrone as claimed in claim 1, characterized in that: The preparation method comprises: In the presence of a first catalyst, allowing benzanthrone and p-chlorobenzoyl chloride to react at a first set temperature to obtain an intermediate; In the presence of a second catalyst, reacting the intermediate with an amine compound at a second set temperature to obtain the benzanthrone-based compound; Wherein, the amine compound is morpholine, piperidine, diethylamine, dipropylamine or diphenylamine; The first set temperature is 35°C-45°C, the first catalyst is a Lewis acid, the second set temperature is 75°C-110°C, the second catalyst includes a main catalyst and an auxiliary agent, the main catalyst is at least one of palladium acetate, tetrakis(triphenylphosphine)palladium, and Pd(pddf)Cl2, and the auxiliary agent is a phosphorus ligand.

5. The method for preparing a compound based on benzanthrone according to claim 4, characterized in that: The molar ratio of the p-chlorobenzoyl chloride, the benzothrone and the first catalyst is 1-1.2:1:2-2.

2.

6. The method for preparing a compound based on benzanthrone according to claim 4, characterized in that: The molar ratio of the intermediate, the amine compound, the main catalyst and the auxiliary agent is 1:1-1.2:0.001-0.1:0.001-0.

1.

7. The method for preparing a compound based on benzanthrone according to any one of claims 4 to 6, characterized in that: The intermediate is reacted with the amine compound under an inert and alkaline environment.

8. The method for preparing a compound based on benzanthrone according to claim 7, characterized in that: The alkaline environment is provided by at least one of the following bases: cesium carbonate, sodium carbonate, potassium carbonate, sodium acetate, sodium tert-butoxide, potassium tert-butoxide.

9. The method for preparing a compound based on benzanthrone according to claim 8, characterized in that: The molar ratio of the intermediate to the base is 1:0.5-3.

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