A method for treating solid waste in the production process of photoinitiator 907

Abstract

The present invention relates to a method for treating solid waste produced during the production of photoinitiator 907. The method comprises subjecting the solid waste to pretreatment and distillation to separate and obtain three fractions, wherein the first fraction is mainly tributylamine, the second fraction is mainly photoinitiator 907 and by-product impurities, and the third fraction is mainly photoinitiator 907; the first fraction is further purified by vacuum distillation to obtain tributylamine, which is then mixed with bromobutane for reaction to obtain tetrabutylammonium bromide; the obtained tetrabutylammonium bromide can be used as a catalyst in the production of photoinitiator 907, thereby turning waste into treasure, reducing the pressure on solid waste treatment, being environmentally friendly, meeting the requirements of green chemistry, and helping to reduce raw material procurement costs and production costs.

Description

Technical Field

[0001] The present invention belongs to the field of photoinitiators and relates to a method for treating solid waste in the production process of photoinitiator 907. Background Art

[0002] 2-Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (photoinitiator 907) is widely used due to its high initiation efficiency, low price advantage and deep curing ability suitable for colored systems.

[0003] At present, the industrialized process flow of photoinitiator 907 is as follows: first, Friedel-Crafts acylation, chlorination, epoxidation, and morpholine substitution are used to prepare the intermediate 2-methyl-1-(4-chlorochlorophenyl)-2-morpholine-1-propanone, and then 2-methyl-1-(4-chlorochlorophenyl)-2-morpholine-1-propanone is subjected to methylthio substitution and purification to obtain photoinitiator 907. During the methylthio substitution and purification process, due to the harsh reaction conditions and the use of a large amount of phase transfer catalyst for auxiliary reaction, a large amount of solid waste is generated during the production process. The traditional method of directly disposing of the waste as hazardous waste not only results in a waste of raw materials and energy, resulting in a significant increase in the production costs of enterprises, but also easily causes serious pollution to the environment.

[0004] Tetrabutylammonium bromide (TBAB), a key raw material used in the production process of photoinitiator 907, produces tributylamine, a highly toxic chemical that poses significant health and safety risks. Its vapor can form an explosive mixture with air and can easily cause combustion and explosion when exposed to open flames or high temperatures. Therefore, tributylamine is extremely unsafe in transportation and storage.

[0005] Therefore, it is still of great significance to develop a method for resource-based treatment of solid waste in the production of photoinitiator 907. Summary of the Invention

[0006] The object of the present invention is to provide a method for treating solid waste in the production process of photoinitiator 907. The treatment method comprises subjecting the solid waste to pretreatment and distillation to separate and obtain three fractions, wherein the first fraction is mainly tributylamine, the second fraction is mainly photoinitiator 907 and by-product impurities, and the third fraction is mainly photoinitiator 907; the first fraction is further purified by vacuum distillation to obtain tributylamine, and then mixed with bromobutane to react to obtain tetrabutylammonium bromide; the obtained tetrabutylammonium bromide can be used as a catalyst in the production of photoinitiator 907, realizing the transformation of waste into treasure, reducing the pressure of solid waste treatment, being environmentally friendly, meeting the requirements of green chemistry, and being conducive to reducing raw material procurement costs and production costs.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for treating solid waste in the production process of photoinitiator 907, the method comprising the following steps:

[0009] (1) Pretreatment: distilling the solid waste to obtain the first fraction, the second fraction, and the third fraction in sequence;

[0010] Wherein, in the first fraction, the mass percentage of tributylamine is 50% to 90%, such as 55%, 60%, 65%, 70%, 75%, 80% or 85%, etc.;

[0011] In the second fraction, the mass percentage of the photoinitiator 907 is 50% to 80%, such as 55%, 60%, 65%, 70% or 75%.

[0012] In the third fraction, the mass percentage of the photoinitiator 907 is 80% to 90%, such as 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88% or 89%.

[0013] (2) Collection and utilization of tributylamine: the first fraction obtained in step (1) is subjected to reduced pressure distillation to obtain a distillate fraction; the mass percentage of tributylamine in the obtained distillate fraction is ≥90%; for example, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%, etc., the distillate fraction is mixed with bromobutyl in the presence or absence of a solvent, and reacted to obtain tetrabutylammonium bromide.

[0014] The production process of photoinitiator 907 includes a methylthio substitution reaction, which requires the use of a large amount of phase transfer catalyst for auxiliary reaction. In the subsequent product separation process, a large amount of solid waste will be produced. Traditional treatment methods generally adopt the method of directly treating the above-mentioned solid waste as hazardous waste, resulting in a waste of raw materials and energy, increasing the production cost of the enterprise, and improper treatment can easily cause serious environmental pollution. In order to solve the above problems, the present invention provides a resource-based treatment method for solid waste in the production process of photoinitiator 907.

[0015] The present invention has found through research that the main components of solid waste include photoinitiator 907, tributylamine and other by-product impurities; wherein, tributylamine is obtained by converting the phase transfer catalyst tetrabutylammonium bromide during the reaction process; tributylamine is a highly toxic chemical and has a large health and safety risk. Its vapor and air can form an explosive mixture, which can easily cause combustion and explosion when exposed to open flames and high heat, and is extremely unsafe in transportation and storage; based on the above research findings, the treatment method of the present invention pre-treats the solid waste by distillation and separates it to obtain a first fraction, a second fraction and a third fraction, wherein the mass percentage of tributylamine in the first fraction is 50% to 90%, and the mass percentage of photoinitiator 907 in the third fraction is 80% to 90%; the above-mentioned first fraction is further subjected to reduced pressure distillation to obtain a distillation fraction with a mass percentage of tributylamine ≥90%, and it is used as a raw material for reaction with butyl bromide The obtained tetrabutylammonium bromide can be used as a raw material in the production process of photoinitiator 907, thereby reducing the raw material procurement cost and the production cost, and converting tributylamine into tetrabutylammonium bromide avoids the risk of hazardous waste containing a large amount of tributylamine in the transportation and storage process, thereby reducing environmental and safety risks. The present invention adopts the above-mentioned treatment method to effectively treat the solid waste in the production process of photoinitiator 907, reduce the pressure of hazardous waste treatment and environmental pressure, and turn waste into treasure. The third fraction is rich in photoinitiator 907 (the content is 80% to 90%), and a photoinitiator 907 finished product with good appearance can be obtained after purification, thereby improving the product yield. The tributylamine in the first fraction is converted into tetrabutylammonium bromide through reaction and reused in the methylthio substitution process, thereby achieving the purpose of resource recycling, being environmentally friendly, meeting the requirements of green chemistry, and reducing production costs.

[0016] The purity of the tetrabutylammonium bromide obtained by the treatment method of the present invention can reach above 95%, and after further recrystallization and purification, the purity of the finished tetrabutylammonium bromide can reach above 99%; and the yield of the finished tetrabutylammonium bromide can reach above 70%.

[0017] Preferably, the vacuum degree of the distillation in step (1) is -0.1 MPa to -0.092 MPa.

[0018] Preferably, during the distillation in step (1), the top temperature of the tower receiving the first fraction is 170°C to 180°C, for example, 171°C, 172°C, 173°C, 174°C, 175°C, 176°C, 177°C, 178°C or 179°C.

[0019] Preferably, during the distillation in step (1), the temperature of the top of the tower receiving the second fraction is 190°C to 195°C, such as 191°C, 192°C, 193°C or 194°C.

[0020] Preferably, during the distillation in step (1), the temperature of the top of the tower receiving the third fraction is 205°C to 210°C, such as 206°C, 207°C, 208°C or 209°C.

[0021] The treatment method of the present invention adopts the above-mentioned vacuum degree and tower top receiving temperature to facilitate pretreatment distillation to obtain the above-mentioned three fractions, thereby facilitating the resource recovery and utilization of tributylamine and photoinitiator 907 in solid waste.

[0022] The tower top temperature mentioned in the present invention refers to the cut-off temperature.

[0023] Preferably, in the solid waste of step (1), the mass percentage of photoinitiator 907 is 40% to 50%, for example, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48% or 49%, and the mass percentage of tributylamine is 10% to 20%, for example, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%, etc.

[0024] In the treatment method of the present invention, the content of photoinitiator 907 in the third fraction is 80% to 90%. Based on the amount of solid waste added as 100%, the mass proportion of the third fraction can reach 30% to 40%. A photoinitiator 907 product with good appearance can be directly prepared with high yield.

[0025] Preferably, during the reduced pressure distillation in step (2), the temperature of the top of the tower receiving the distillation fraction is 45°C to 50°C, such as 46°C, 47°C, 48°C or 49°C.

[0026] Preferably, the molar ratio of bromobutane in step (2) to the molar ratio of tributylamine in the distillation fraction is 0.8 to 0.85:1, for example, 0.81:1, 0.82:1, 0.83:1 or 0.84:1, etc.; the above molar ratio is conducive to the complete conversion of bromobutane.

[0027] Preferably, the solvent in step (2) is selected from any one or a combination of at least two of toluene, n-butanol, cyclohexane, ethyl acetate, methanol, ethanol, dichloroethane or acetonitrile, preferably acetonitrile.

[0028] Preferably, the reaction temperature in step (2) is 80°C to 85°C; for example, 81°C, 82°C, 83°C or 84°C.

[0029] Preferably, the reaction in step (2) is carried out under reflux.

[0030] Preferably, when a solvent is involved in step (2), desolventizing is further performed after the reaction is completed to obtain crude tetrabutylammonium bromide; desolventizing is preferably performed by distillation.

[0031] Preferably, after the reaction in step (2) is completed, recrystallization is further included to obtain a tetrabutylammonium bromide product with a purity of ≥99% (exemplarily including 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8% or 99.9%, etc.).

[0032] In the treatment method of the present invention, the purity of the crude tetrabutylammonium bromide obtained after desolventizing can reach 95% or above, and can be directly applied to the methylthio substitution process of the light-returning initiator 907 or other reactions; the crude product can also be further recrystallized to obtain a finished tetrabutylammonium bromide with a purity of ≥99%; based on the amount of bromobutane added, the yield of the finished tetrabutylammonium bromide obtained by recrystallization reaches more than 70%, thereby realizing the resource recovery and utilization of solid waste.

[0033] Preferably, the recrystallization solvent is selected from any one of ethyl acetate, butyl acetate or n-hexane, or a combination of at least two thereof.

[0034] Preferably, in the recrystallization, the mass ratio of the crude tetrabutylammonium bromide to the recrystallization solvent is 1:1 to 1.3, for example, 1:1.1 or 1:1.2.

[0035] Preferably, the tetrabutylammonium bromide obtained in step (2) is used in the production of photoinitiator 907.

[0036] Preferably, the processing method further comprises purifying the third fraction to obtain a finished photoinitiator 907 with a purity ≥95% (exemplary examples include 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99% or 99.5%, etc.).

[0037] Preferably, the purification method comprises recrystallization; preferably, the recrystallization solvent is selected from any one of methanol, acetone, ethanol, petroleum ether, dichloroethane, ethyl acetate, toluene, n-hexane, and cyclohexane, or a combination of at least two thereof.

[0038] Preferably, the purification method includes: mixing the third fraction with a recrystallization solvent, heating to dissolve, then cooling to crystallize, and separating the solid and liquid to obtain a photoinitiator 907 finished product with a purity ≥95% (exemplary examples include 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99% or 99.5%, etc.).

[0039] Preferably, the temperature for heating and dissolving is selected from 55°C to 60°C, such as 56°C, 57°C, 58°C or 59°C.

[0040] In the treatment method of the present invention, the mass percentage of photoinitiator 907 in the third fraction is 80% to 90%. The above-mentioned recrystallization operation can directly obtain the finished photoinitiator 907 with a purity of ≥95%, thereby realizing the resource utilization of solid waste and turning waste into treasure.

[0041] Preferably, the treatment method further comprises returning the second fraction obtained in step (1) to the pretreatment step of step (1).

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The treatment method of the present invention comprises pre-treating and distilling solid waste to separate a first fraction, a second fraction, and a third fraction, wherein the first fraction is rich in tributylamine and the third fraction is rich in photoinitiator 907; subjecting the first fraction to vacuum distillation to further improve the purity of the tributylamine, and then reacting the fraction with bromobutane to obtain tetrabutylammonium bromide; the above process realizes the resource utilization of the tributylamine in the solid waste, and the obtained tetrabutylammonium bromide can be used in the production of photoinitiator 907, thereby reducing the solid waste treatment cost and the raw material procurement cost, achieving the purpose of resource recycling, being environmentally friendly, and meeting the requirements of green chemistry. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] Example 1

[0046] This embodiment provides a method for treating solid waste during the production process of photoinitiator 907;

[0047] The raw material solid waste was taken from the solid waste generated in the photoinitiator 907 production workshop. The composition of the solid waste was tested: based on the mass of the solid waste as 100%, the mass of the photoinitiator 907 accounted for 46% and the mass of tributylamine accounted for 17%.

[0048] The processing method specifically includes the following steps:

[0049] (1) 5000 g of solid waste was added to a distillation kettle for distillation treatment. The vacuum degree was maintained at -0.1-0.092 MPa. When the top temperature reached 170°C to 180°C and the reflux ratio was 5:5, the first fraction was collected.

[0050] When the top temperature reaches 190-195°C, the second fraction is received;

[0051] When the top temperature reaches 205-210°C, the third fraction is received;

[0052] Detecting the composition of the fractions, wherein, based on the mass of the first fraction being 100%, the mass percentage of tributylamine in the first fraction is 80%;

[0053] Based on the mass of the second fraction being 100%, the mass percentage of the photoinitiator 907 in the second fraction is 62%;

[0054] Taking the mass of the third fraction as 100%, the mass percentage of the photoinitiator 907 in the third fraction is 86%;

[0055] The above content was obtained by gas chromatography test;

[0056] Based on the added amount of the raw solid waste being 100%, the mass percentage of the third fraction is 40%;

[0057] (2) taking the first fraction obtained in step (1), performing vacuum distillation until the top temperature of the tower is 45-50° C., and then collecting the distillate;

[0058] The composition of the distillation fraction was detected, and the mass percentage of tributylamine was 94%;

[0059] Adding bromobutyl and acetonitrile to the above distillation fraction, wherein the molar ratio of tributylamine to bromobutyl in the distillation fraction is 1:0.85; the weight of acetonitrile added is the same as that of bromobutyl, heating to 80-85° C. and reflux reaction for 40 hours, and removing acetonitrile by atmospheric distillation to obtain crude tetrabutylammonium bromide;

[0060] The purity of crude tetrabutylammonium bromide was 95.5%;

[0061] The crude tetrabutylammonium bromide is recrystallized using ethyl acetate as a solvent, with the weight ratio of the crude product to ethyl acetate being 1:1.2, to obtain a finished tetrabutylammonium bromide having a purity of over 99%. The yield of the tetrabutylammonium bromide is over 80% based on the amount of bromobutane added.

[0062] Example 2

[0063] The treatment method in this embodiment includes: mixing the third fraction obtained in Example 1 with methanol, with the mass ratio of the third fraction to the volume of methanol being 0.58 g / mL, heating to 55° C., stirring until completely dissolved and clarified, then cooling to crystallize, and centrifuging to obtain the finished photoinitiator 907 with a purity of more than 95% and a yield of more than 80%.

[0064] Example 3

[0065] This embodiment provides a method for treating solid waste during the production process of photoinitiator 907;

[0066] The composition of raw solid waste is as follows:

[0067] Based on the mass of the solid waste being 100%, the mass percentage of the photoinitiator 907 is 50%, the mass percentage of the tributylamine is 13%, and the other parameters and conditions are exactly the same as those in Example 1.

[0068] The processing method specifically includes the following steps:

[0069] (1) 5000 g of solid waste was added to a distillation kettle for distillation, with the vacuum maintained at ≤-0.09 MPa. When the top temperature reached 170°C to 180°C and the reflux ratio was 5:5, the first fraction was collected;

[0070] When the top temperature reaches 190-195°C, the second fraction is received;

[0071] When the top temperature reaches 205-210°C, the third fraction is received;

[0072] Detecting the composition of the fractions, wherein, based on the mass of the first fraction being 100%, the mass percentage of tributylamine in the first fraction is 60%;

[0073] Based on the mass of the second fraction being 100%, the mass percentage of the photoinitiator 907 in the second fraction is 70%;

[0074] Taking the mass of the third fraction as 100%, the mass percentage of the photoinitiator 907 in the third fraction is 88%;

[0075] The above content was obtained by gas chromatography test;

[0076] Based on the addition amount of the raw solid waste as 100%, the mass percentage of the third fraction is 45%;

[0077] (2) taking the first fraction obtained in step (1), performing vacuum distillation until the top temperature of the tower is 45° C. to 50° C., and then collecting the distillate;

[0078] The composition of the distillation fraction was detected, and the mass percentage of tributylamine was 94.8%;

[0079] Adding bromobutyl and acetonitrile to the distillation fraction, wherein the molar ratio of tributylamine to bromobutyl in the distillation fraction is 1:0.82; adding bromobutyl and acetonitrile in equal weights, heating to 80° C. and reflux reaction for 45 hours, and removing acetonitrile by atmospheric distillation to obtain crude tetrabutylammonium bromide;

[0080] The purity of crude tetrabutylammonium bromide was 96.1%;

[0081] The crude tetrabutylammonium bromide was recrystallized using ethyl acetate as a solvent at a weight ratio of the crude product to ethyl acetate of 1:1.3 to obtain a finished tetrabutylammonium bromide with a purity exceeding 99%. The yield of tetrabutylammonium bromide was 86% based on the amount of bromobutane added.

[0082] Example 4

[0083] The only difference between this embodiment and embodiment 1 is that the solvent in the reaction in step (2) is replaced by methanol in an equal weight ratio from acetonitrile, and the other parameters and conditions are exactly the same as those in embodiment 1.

[0084] In this embodiment, the purity of the crude tetrabutylammonium bromide obtained in step (2) is 79.46%. It is recrystallized from ethyl acetate to obtain a finished tetrabutylammonium bromide with a purity of 98%. Based on the amount of bromobutane added, the yield of tetrabutylammonium bromide is 61.3%.

[0085] Example 5

[0086] The only difference between this embodiment and embodiment 1 is that the solvent in the reaction in step (2) is replaced by toluene in an equal weight ratio of acetonitrile, and the other parameters and conditions are exactly the same as those in embodiment 1.

[0087] In this embodiment, the purity of the crude tetrabutylammonium bromide obtained in step (2) is 65.12%. It is recrystallized from ethyl acetate to obtain a finished tetrabutylammonium bromide with a purity of 95%. Based on the amount of bromobutane added, the yield of tetrabutylammonium bromide is 48.12%.

[0088] Example 6

[0089] The only difference between this embodiment and embodiment 1 is that the solvent in the reaction in step (2) is replaced by dichloroethane in an equal weight ratio of acetonitrile, and the other parameters and conditions are exactly the same as those in embodiment 1.

[0090] In this embodiment, the purity of the crude tetrabutylammonium bromide obtained in step (2) is 72.26%. It is recrystallized from ethyl acetate to obtain a finished tetrabutylammonium bromide with a purity of 98%. Based on the amount of bromobutane added, the yield of tetrabutylammonium bromide is 78%.

[0091] Example 7

[0092] The only difference between this embodiment and embodiment 1 is that no solvent is added in the reaction in step (2). After the temperature is raised and the reflux reaction is completed, a crude tetrabutylammonium bromide is obtained. The product is clearly separated into layers. The purity of the lower layer is tested to be 88.18%. Recrystallization is carried out using ethyl acetate to obtain a finished tetrabutylammonium bromide with a purity of 98.15%. Based on the amount of bromobutane added, the yield of tetrabutylammonium bromide is 42%.

[0093] Example 8

[0094] The only difference between this embodiment and embodiment 1 is that the recrystallization solvent in step (2) is replaced by n-hexane in equal weight, and the other parameters and conditions are exactly the same as those in embodiment 1.

[0095] The purity of the finished tetrabutylammonium bromide obtained in this embodiment is 98.7%, and the yield of tetrabutylammonium bromide is 85%.

[0096] Example 9

[0097] The only difference between this embodiment and embodiment 1 is that the recrystallization solvent in step (2) is replaced by butyl acetate in equal weight, and the other parameters and conditions are exactly the same as those in embodiment 1.

[0098] The purity of the finished tetrabutylammonium bromide obtained in this embodiment is 99%, and the yield of tetrabutylammonium bromide is 80%.

[0099] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for treating solid waste in the production process of photoinitiator 907, characterized in that: The processing method comprises the following steps: (1) Pretreatment: distilling the solid waste to obtain the first fraction, the second fraction, and the third fraction in sequence; Wherein, in the first fraction, the mass percentage of tributylamine is 50% to 90%; In the second fraction, the mass percentage of the photoinitiator 907 is 50% to 80%; In the third fraction, the mass percentage of the photoinitiator 907 is 80% to 90%; (2) Collection and utilization of tributylamine: subjecting the first fraction obtained in step (1) to vacuum distillation to obtain a distillation fraction; the mass percentage of tributylamine in the obtained distillation fraction is ≥90%; The distillation fraction is mixed with butyl bromide in the presence or absence of a solvent to react to obtain tetrabutylammonium bromide; Wherein, the vacuum degree of distillation in step (1) is -0.1MPa to -0.092MPa; During the distillation in step (1), the temperature of the top of the tower receiving the first fraction is 170°C to 180°C, the temperature of the top of the tower receiving the second fraction is 190°C to 195°C, and the temperature of the top of the tower receiving the third fraction is 205°C to 210°C.

2. The processing method according to claim 1, characterized in that In the solid waste of step (1), the mass percentage of the photoinitiator 907 is 40% to 50%, and the mass percentage of tributylamine is 10% to 20%.

3. The processing method according to claim 1, characterized in that During the reduced pressure distillation in step (2), the top temperature of the tower receiving the distillation fraction is 45°C to 50°C.

4. The processing method according to claim 1, characterized in that The ratio of the molar amount of bromobutane in step (2) to the molar amount of tributylamine in the distillation fraction is 0.8 to 0.85:

1.

5. The processing method according to claim 1, characterized in that The solvent in step (2) is selected from any one of toluene, methanol, ethanol, dichloroethane or acetonitrile, or a combination of at least two thereof.

6. The processing method according to claim 1, characterized in that The temperature for carrying out the reaction in step (2) is 80°C to 85°C.

7. The processing method according to claim 6, characterized in that The reaction in step (2) is carried out under reflux.

8. The processing method according to claim 1, characterized in that When a solvent is involved in step (2), desolventizing is further performed after the reaction is completed to obtain crude tetrabutylammonium bromide.

9. The processing method according to claim 8, characterized in that: After the reaction is completed, distillation and desolventization are performed to obtain crude tetrabutylammonium bromide.

10. The processing method according to claim 1, characterized in that: After the reaction in step (2) is completed, recrystallization is further performed to obtain a finished tetrabutylammonium bromide product with a purity of ≥99%.

11. The processing method according to claim 10, characterized in that: The recrystallization solvent is selected from any one of ethyl acetate, butyl acetate or n-hexane, or a combination of at least two thereof.

12. The processing method according to claim 10, characterized in that: In the recrystallization, the mass ratio of the crude tetrabutylammonium bromide to the recrystallization solvent is 1:1 to 1.

3.

13. The processing method according to any one of claims 1 to 12, characterized in that: The tetrabutylammonium bromide obtained in step (2) is used in the production of photoinitiator 907.

14. The processing method according to claim 1, characterized in that The processing method further includes purifying the third fraction to obtain a finished photoinitiator 907 with a purity of ≥95%.

15. The processing method according to claim 14, characterized in that: The purification method includes recrystallization.

16. The processing method according to claim 15, characterized in that: The recrystallization solvent used to purify the third fraction is selected from any one of methanol, acetone, ethanol, petroleum ether, dichloroethane, ethyl acetate, toluene, n-hexane, and cyclohexane, or a combination of at least two thereof.

17. The processing method according to claim 15, characterized in that: The purification method comprises: mixing the third fraction with a recrystallization solvent, heating to dissolve, then cooling to crystallize, and performing solid-liquid separation to obtain a finished photoinitiator 907 with a purity of ≥95%.

18. The processing method according to claim 17, characterized in that: The temperature for heating and dissolving is selected from 55°C to 60°C.

19. The processing method according to claim 1, characterized in that The treatment method further comprises returning the second fraction obtained in step (1) to the pretreatment step of step (1).