Novel preparation method of amino ketone photoinitiator

Abstract

The invention relates to the technical field of new material fine chemicals, in particular to a novel preparation method of an amino ketone photoinitiator, which comprises the following steps: reacting a raw material as shown in a structural formula A with a reagent B under proper reaction conditions Conditions, and reacting with a compound C and a compound D to obtain the amino ketone photoinitiator. The compound can be used for preparing a series of photoinitiator target products with aminoketone structural formulas, and the compound is a photoinitiator with higher light absorption capacity and higher initiation activity, and is easy to prepare and store and low in cost.

Description

Technical Field

[0001] This invention relates to the field of new materials and fine chemicals, specifically a novel preparation method for an amino ketone photoinitiator. Background Technology

[0002] α-Aminoacetophenone compounds are commonly used photoinitiators for free radical photopolymerization.

[0003] Extensive searches revealed CN116003273A, which discloses an α-aminoketone compound, its preparation method, and its application in the field of photocuring.

[0004] Among the existing technologies, CN116003273A reduces the amount of small molecule reactive diluent required and has high sensitivity, which greatly promotes its application in the field of UV radiation curing.

[0005] However, this process involves cumbersome reaction steps and requires a chlorine source, generating large amounts of HCl gas, which is extremely environmentally unfriendly. Therefore, further improvements are needed from both an economic and environmental perspective. Thus, considering industrial applications, environmental protection in manufacturing processes, and environmental friendliness in consumer applications, the development of novel photoinitiators should not only focus on solving the aforementioned challenging problems and providing green, non-toxic, and environmentally friendly new compounds, but also strive to ensure that these new compounds are as cost-competitive as possible while maintaining overall performance competitiveness. Summary of the Invention

[0006] The purpose of this invention is to provide a novel preparation method for amino ketone photoinitiators, which can effectively solve the problems in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a novel preparation method for an aminoketone photoinitiator, the synthesis reaction formula of which is as follows: R1 or R2 is selected from any one of the independent C1-C10 straight-chain or branched alkyl groups and C4-C10 cycloalkyl groups; or R1 and R2 are connected to each other or form a five-membered or six-membered ring group through -O-, -S-, -N-; R3 is Cl or Br; the base includes inorganic bases and organic bases, the inorganic base is a hydroxide, carboxylate, phosphate, carbonate, sulfonate or ammonia of a metal cation, the organic base is an alkylamine, aromatic amine, heterocyclic nitrogen compound; conditions are one or more of the following: catalyst, light, heat, ultrasound, microwave, vacuum, pressure or solvent; the raw material C is a secondary amine salt, including secondary amine hydrochloride, secondary amine sulfate, secondary amine carbonate, secondary amine carboxylate, secondary amine phosphate or mixtures thereof; The preparation method specifically includes the following steps: S1. Compounds A and B undergo a Friedel-Crafts acylation reaction catalyzed by a Lewis acid to yield compound II. ; S2, Compound II then undergoes an ammonolysis reaction with a secondary amine salt under alkaline conditions to generate Compound III. ; S3 and compound III react with benzyl halide D to form a quaternary ammonium salt of an α-amino ketone, which then undergoes a Steve-Vs rearrangement reaction under alkaline conditions to generate the target compound. .

[0008] Preferably, in step S1, biphenyl is dissolved in dichloroethane, a catalyst is added at 0°C, and 2-chloropropionyl chloride is added dropwise. After the addition is complete, the reaction is carried out at this temperature for 2-6 hours. The amount of raw material B added is in the range of 1.0-3.0 equivalents, preferably in the range of 1.0-1.4 equivalents. The amount of Lewis acid catalyst added is in the range of 0.05-2.5 equivalents, preferably in the range of 1.0-1.2 equivalents. After the addition is complete, the holding time is 2-6 hours, preferably 3-3.5 hours. In step S2, the amount of raw material C added is in the range of 0.5-4.0 equivalents, preferably in the range of 1.0-2.5 equivalents. The amount of Base added is in the range of 1.0-4.0, preferably in the range of 2.0-3.0.

[0009] Preferably, the Lewis acid in S1 is selected from aluminum trichloride, ferric chloride, zinc chloride, and titanium tetrachloride, with aluminum trichloride and ferric chloride being the most preferred.

[0010] Preferably, in S2, the Base is an organic base, preferably triethylamine and N,N-diisopropylethylamine.

[0011] Preferably, in S2, the secondary amine salt is a secondary amine hydrochloride, more preferably a dimethylamine hydrochloride, diethylamine hydrochloride, morpholine hydrochloride, or pyridine hydrochloride.

[0012] Preferably, in step S3, the quaternary ammonium salt compound is dissolved in a 20%-40wt% sodium hydroxide solution and rearranged at 40-90°C for 5-6 hours.

[0013] Preferably, the catalyst in the Conditions is a Lewis acid compound, including but not limited to aluminum trichloride, ferric trichloride, magnesium chloride, barium chloride, magnesium chloride, etc.; the wavelength range of the light is 200-780 nanometers; the heat index system is carried out under heating conditions; the pressure is that the reaction system is carried out under pressure conditions of 0.01-200 atmospheres; the solvent is an aromatic or aliphatic hydrocarbon, a halogenated aromatic or aliphatic hydrocarbon, various esters, alcohols, ethers, ketones, amides, water or supercritical carbon dioxide and other green solvents, or any two or more of the above mixed systems.

[0014] Preferably, after the rearrangement reaction is completed, the product is further purified by cooling the reaction to room temperature, extracting with ethyl acetate or dichloromethane, washing the organic phase twice with water, drying with anhydrous sodium sulfate, and concentrating to obtain the target compound.

[0015] Preferably, after the reaction is complete and extraction is finished, the EA or DCE added to the product is concentrated and then recovered for reuse.

[0016] A hybrid system curable by ultraviolet radiation, comprising at least one polymerizable olefinic unsaturated photopolymerizable compound and an amino ketone photoinitiator according to any one of claims 1-9.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: Using biphenyl as a raw material reduces the cost of raw materials. In addition, the preparation method of the present invention has a high yield, which can reach more than 80%, and a purity of more than 97%.

[0018] Compared with existing products, this invention uses inexpensive and readily available industrial-grade raw materials as a starting point, and biphenyl as a key group to prepare α-amino aromatic ketones through easy-to-operate processes such as Friedel-Crafts reaction, substitution, and rearrangement, thereby improving photoinitiation efficiency. Meanwhile, this compound is an environmentally friendly, non-toxic, and highly efficient photoinitiator, avoiding the release of volatile toxic small molecule organic compounds during the photocuring process, or the generation of irritating or unpleasant odors, or physiological toxicity caused by compound migration. It plays a significant role in promoting the application of ultraviolet radiation photocuring.

[0019] Exemplary, and not limiting, compounds of novel preparation methods for amino ketone photoinitiators that can be prepared via the techniques disclosed in this application have the following structures: . Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 Under nitrogen protection, 154 g of biphenyl was added to 462 g of dichloroethane, the temperature was lowered to 0°C, 147 g of anhydrous aluminum trichloride was slowly added, and after stirring for 30 minutes, 2-chloropropionyl chloride was slowly added dropwise at the same temperature. After the addition was completed, the mixture was kept at the same temperature for 3 hours, then quenched with ice water, the organic layer was separated, washed with water until neutral, dried, and concentrated and purified to obtain the Friedel-crafts acylated intermediate. The above-mentioned white solid was added to 776 g of dichloroethane and stirred to dissolve. 25 g of anhydrous aluminum trichloride was added, and stirring was continued for 30 minutes. 211 g of dimethylamine hydrochloride was added and stirred to dissolve. 339 g of triethylamine was added and reacted at room temperature for 3-4 hours. TLC was used to detect the disappearance of the Friedel-Crafts product. 244 g of water was added and stirred for 30 minutes. The mixture was allowed to stand, and the layers were separated. The organic phase was collected. The aqueous phase was extracted twice with dichloroethane. The organic phases were combined, and the solvent was removed by distillation. The crude product was recrystallized from ethanol to obtain a white intermediate. Finally, the above-mentioned ammoniated intermediate was added to a reaction flask, 506 g of toluene was added, 138 g of benzyl chloride was slowly added dropwise, the temperature was raised to 90°C and reacted for 10 hours, liquid alkali was added and refluxed for 2 hours, the organic phase was separated after cooling, and the crude product was obtained after extraction and drying. After recrystallization with ethanol, 294 g of the target product was obtained, with a total yield of 86.1% and a GC purity of 97.93%.

[0022] Example 2 Under nitrogen protection, 154 g of biphenyl was added to 462 g of dichloromethane, the temperature was lowered to 0°C, 147 g of anhydrous aluminum trichloride was slowly added, and after stirring for 30 minutes, 127 g of 2-chloropropionyl chloride was slowly added dropwise at the same temperature. After the addition was completed, the mixture was kept at the same temperature for 3 hours, then quenched with ice water, the organic layer was separated, washed with water until neutral, dried, and concentrated and purified to obtain the Friedel-crafts acylated intermediate. The above-mentioned white solid was added to 776 g of dichloromethane and stirred to dissolve. 25 g of anhydrous aluminum trichloride was added, and stirring was continued for 30 minutes. Then, 306 g of morpholine hydrochloride was added and stirred to dissolve. 327 g of triethylamine was added and reacted at room temperature for 3-4 hours. TLC was used to detect the disappearance of Friedel-Crafts products. Then, 258 g of water was added and stirred for 30 minutes. The mixture was allowed to stand, and the layers were separated. The organic phase was collected, and the aqueous phase was extracted twice with dichloroethane. The organic phases were combined, and the solvent was removed by distillation. The crude product was recrystallized from ethanol to obtain a white intermediate. Finally, the above-mentioned ammoniated intermediate was added to a reaction flask, 600 g of toluene was added, 126 g of benzyl chloride was slowly added dropwise, the temperature was raised to 90°C and reacted for 10 hours, liquid alkali was added and refluxed for 2 hours, the organic phase was separated after cooling, and the crude product was obtained after extraction and drying. After recrystallization with ethanol, 319.97 g of the target product was obtained, with a total yield of 83% and a GC purity of 98.11%.

[0023] Example 3 Under nitrogen protection, 77 g of biphenyl was added to 231 g of dichloroethane, the temperature was lowered to 0°C, 74 g of anhydrous aluminum trichloride was slowly added, and after stirring for 30 minutes, 64 g of 2-chloropropionyl chloride was slowly added dropwise at the same temperature. After the addition was completed, the mixture was kept at the same temperature for 3 hours, then quenched with ice water, the organic layer was separated, washed with water until neutral, dried, and concentrated and purified to obtain the Friedel-crafts acylated intermediate. The above-mentioned white solid was added to 380 g of dichloroethane and stirred to dissolve. 13 g of anhydrous aluminum trichloride was added, and stirring was continued for 30 minutes. Then, 138 g of diethylamine hydrochloride was added and stirred to dissolve. Then, 164 g of triethylamine was added and reacted at room temperature for 3-4 hours. TLC was used to detect the disappearance of Friedel-Crafts products. Then, 129 g of water was added and stirred for 30 minutes. The mixture was allowed to stand, and the layers were separated. The organic phase was collected, and the aqueous phase was extracted twice with dichloroethane. The organic phases were combined, and the solvent was removed by distillation. The crude product was recrystallized from ethanol to obtain a white intermediate. Finally, the above-mentioned ammoniated intermediate was added to a reaction flask, 200 g of toluene was added, 85 g of benzyl chloride was slowly added dropwise, the temperature was raised to 90 °C and reacted for 10 hours, liquid alkali was added and refluxed for 2 hours, the organic phase was separated after cooling, and the crude product was obtained after extraction and drying. After recrystallization with ethanol, 158 g of the target product was obtained, with a total yield of 85% and a GC purity of 97.98%.

[0024] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0025] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A novel preparation method for an aminoketone-based photoinitiator, characterized in that, The synthesis reaction formula is as follows: R1 or R2 is selected from any one of the independent C1-C10 straight-chain or branched alkyl groups and C4-C10 cycloalkyl groups; or R1 and R2 are connected to each other or form a five-membered or six-membered ring group through -O-, -S-, -N-; R3 is Cl or Br; the base includes inorganic bases and organic bases, the inorganic base is a hydroxide, carboxylate, phosphate, carbonate, sulfonate or ammonia of a metal cation, the organic base is an alkylamine, aromatic amine, heterocyclic nitrogen compound; conditions are one or more of the following: catalyst, light, heat, ultrasound, microwave, vacuum, pressure or solvent; the raw material C is a secondary amine salt, including secondary amine hydrochloride, secondary amine sulfate, secondary amine carbonate, secondary amine carboxylate, secondary amine phosphate or mixtures thereof; The preparation method specifically includes the following steps: S1. Compounds A and B undergo a Friedel-Crafts acylation reaction catalyzed by a Lewis acid to yield compound II. ； S2, Compound II then undergoes an ammonolysis reaction with a secondary amine salt under alkaline conditions to generate Compound III. ； S3 and compound III react with benzyl halide D to form a quaternary ammonium salt of an α-amino ketone, which then undergoes a Steve-Vs rearrangement reaction under alkaline conditions to generate the target compound. 。 2. The novel preparation method of an aminoketone photoinitiator according to claim 1, characterized in that, In S1, biphenyl is dissolved in dichloroethane, a catalyst is added at 0°C, and 2-chloropropionyl chloride is added dropwise. After the addition is complete, the reaction is carried out at this temperature for 2-6 hours. The amount of raw material B added is in the range of 1.0-3.0 equivalents, preferably in the range of 1.0-1.4 equivalents. The amount of Lewis acid catalyst added is in the range of 0.05-2.5 equivalents, preferably in the range of 1.0-1.2 equivalents. After the addition is complete, the holding time is 2-6 hours, preferably 3-3.5 hours. In S2, the amount of raw material C added is in the range of 0.5-4.0 equivalents, preferably in the range of 1.0-2.5 equivalents. The amount of Base added is in the range of 1.0-4.0, preferably in the range of 2.0-3.

0.

3. A novel preparation method for an amino ketone photoinitiator according to claim 1, characterized in that, The Lewis acid in S1 is selected from aluminum trichloride, ferric trichloride, zinc chloride, and titanium tetrachloride, with aluminum trichloride and ferric trichloride being preferred.

4. A novel preparation method for an amino ketone photoinitiator according to claim 1, characterized in that, In S2, the Base is an organic base, preferably triethylamine and N,N-diisopropylethylamine.

5. A novel preparation method of an amino ketone photoinitiator according to claim 1, characterized in that, In S2, the secondary amine salt is a secondary amine hydrochloride, more preferably a dimethylamine hydrochloride, diethylamine hydrochloride, morpholine hydrochloride, or pyridine hydrochloride.

6. A novel preparation method of an amino ketone photoinitiator according to claim 1, characterized in that, In step S3, the quaternary ammonium salt compound is dissolved in a 20%-40wt% sodium hydroxide solution and rearranged at 40-90℃ for 5-6 hours.

7. A novel preparation method for an amino ketone photoinitiator according to claim 1, characterized in that, The catalysts in the Conditions are Lewis acid compounds, including but not limited to aluminum trichloride, ferric trichloride, magnesium chloride, barium chloride, and magnesium chloride; the wavelength range of the light is 200-780 nanometers; the thermal index system is carried out under heating conditions; the pressure is that the reaction system is carried out under pressure conditions of 0.01-200 atmospheres; the solvent is an aromatic or aliphatic hydrocarbon, a halogenated aromatic or aliphatic hydrocarbon, various esters, alcohols, ethers, ketones, amides, water, or supercritical carbon dioxide and other green solvents, or any two or more of the above mixed systems.

8. A novel preparation method of an amino ketone photoinitiator according to claim 1, characterized in that, After the rearrangement reaction is completed, the product is purified. Specifically, the reaction is cooled to room temperature, extracted with ethyl acetate or dichloromethane, the organic phase is washed twice with water, dried with anhydrous sodium sulfate, and concentrated to obtain the target compound.

9. A novel preparation method of an amino ketone photoinitiator according to claim 1, characterized in that, After the reaction is complete and extraction is performed, the EA or DCE added to the product is concentrated and then recovered for reuse.

10. A hybrid system curable by ultraviolet radiation, characterized in that, It contains at least one polymerizable olefinic unsaturated photopolymerizable compound and an amino ketone photoinitiator according to any one of claims 1-9.

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