Phosphinyl compound based on a phospholene structure and a method for preparing the same

Abstract

The application provides a kind of acyloxyphosphine compound based on phospholene structure and a preparation method thereof, and the acyloxyphosphine compound is an acyloxyphosphine compound shown in the following formula (I), which can be used in photocuring technology as a free radical photoinitiator.In addition, this preparation method avoids the use of highly polluting chlorine gas in traditional phosphorus chemical production and the subsequent emission problems caused thereby, and is an extremely environmentally friendly production method.In addition, the method disclosed by the application has mild reaction conditions, short reaction time, simple post-treatment and can obtain a high yield.

Description

Technical Field

[0001] This invention relates to the field of organophosphorus chemistry and chemical engineering, and more specifically, to an acylphosphine oxide compound based on the phosphane fluorene structural unit and its preparation method. Background Technology

[0002] Acylphosphine oxide compounds, due to their unique optical properties, are currently widely used as photoinitiators in photocuring processes, including coatings, 3D printing, UV ink printing, food packaging, and dental materials. The most representative photoinitiator is 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO, structural formula: For this type of acylphosphine oxide compound with two aryl substitutions, there are two main existing synthetic methods: (1) Diarylphosphine chloride (Ar2PCl) is first reacted with an alcohol to obtain diphenylalkoxyphosphine, and then reacted with trimethylbenzoyl chloride (MesCOCl) to obtain the final product (see Patent Document 1 and Patent Document 2); (2) Diarylphosphine chloride (Ar2PCl) is first hydrolyzed to obtain diarylphosphine oxide (Ar2P(O)H), and then reacted with an aromatic aldehyde followed by a one-step oxidation to obtain the target product (see Patent Document 3 and Patent Document 4). In contrast, acylphosphine oxide compounds that link the two aryl groups on the phosphorus atom, i.e., acylphosphine oxide compounds based on the phosphorus fluorene structure (structural formula: However, there are almost no reports on this, with only one Japanese patent involving the synthesis of related products (see Patent Document 5), which uses 9-phenyl-9-phosphafluorene (structural formula: The target product is synthesized using phenylphosphine dichloride (PhPCl2) as a starting material, but this starting material is actually synthesized from phenylphosphine dichloride (PhPCl2), resulting in a complex and inefficient process involving numerous steps. Furthermore, the patent only includes a few acylphosphine oxide compounds without substituents in the phosphonium structure. There are currently no reports on acylphosphine oxide compounds with substituents in the phosphonium structure, thus significantly limiting the further utilization of such compounds.

[0003] As can be seen from the methods reported above, in the prior art, the diarylphosphorus chloride and phenylphosphorus chloride, which are the starting materials, are basic phosphorus chemical products. Industrially, they are prepared from white phosphorus (P4), which requires the use of toxic gas that is not friendly to the environment and human body - chlorine. The process also generates a large amount of waste gas and waste acid during the reaction. As a result, the entire production process is not only energy-intensive, but also extremely polluting to the environment (refer to non-patent literature 1).

[0004] Therefore, given the aforementioned problems, there is an urgent need to find a readily available and easily obtainable raw material to synthesize acylphosphine oxide compounds, especially the rarely reported method for acylphosphine oxide compounds based on the phosphonium structure, in order to solve the current problems.

[0005] Existing technical literature

[0006] Patent documents:

[0007] Patent Document 1: US 4324744A

[0008] Patent Document 2: US4710523A

[0009] Patent Document 3: US5679863A

[0010] Patent Document 4: CN 106905364A

[0011] Patent Document 5: JP2005225793A

[0012] Non-patent literature:

[0013] Non-patent literature 1: Acc. Chem. Res. 2014, 47, 77–87 Summary of the Invention

[0014] The technical problem that the invention aims to solve

[0015] The present invention was made in view of the above-mentioned problems, and its purpose is to provide an acylphosphine oxide compound containing a phosphonium fluorene structural unit, and a method for preparing the same, which can not only be synthesized efficiently but also greatly reduce environmental pollution caused during the production process.

[0016] Solution for solving the problem

[0017] The technical solution of the present invention is as follows:

[0018] The first aspect of the present invention is an acylphosphine oxide compound, which is a compound containing a phosphane fluorene structural unit as shown in formula (I), characterized in that...

[0019]

[0020] Among them, R 1 and R 2 They can be the same or different, each independently being hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, or thiophene.

[0021] In a preferred manner, the R1 and R 2 Each can be independently hydrogen, halogen, methyl, tert-butyl, trifluoromethyl, trifluoromethoxy, nitro, methoxy, ethoxy, or phenyl.

[0022] In a preferred manner, the R 1 and R 2 Each can be independently hydrogen, halogen, methyl, tert-butyl, trifluoromethyl, or trifluoromethoxy.

[0023] R 3 –R 7 Each of them is independently hydrogen, halogen, C1 to C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1 to C6 alkoxy, substituted or unsubstituted phenyl, pyridyl or thiophene.

[0024] In a preferred manner, the R 3 –R 7 Each of these can be independently identified as hydrogen, methyl, methoxy, or phenyl.

[0025] Another aspect of the present invention relates to a method for preparing an acylphosphine oxide compound, which is a method for preparing a compound containing a phosphatene structural unit as shown in formula (I).

[0026]

[0027] In equation (I), R 1 and R 2 They can be the same or different, and can be hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, thiophene.

[0028] Wherein, the R 1 and R 2 Each can be independently hydrogen, halogen, methyl, tert-butyl, trifluoromethyl, or trifluoromethoxy.

[0029] R 3 –R 7 Each of them is independently hydrogen, halogen, C1 to C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1 to C6 alkoxy, substituted or unsubstituted phenyl, pyridyl or thiophene.

[0030] In a preferred manner, the R 3 –R 7 Each can be independently classified as hydrogen, methyl, methoxy, or phenyl.

[0031] The reaction formula for the preparation method is as follows:

[0032]

[0033] The preparation method includes the following steps:

[0034] Step 1-1: Dissolve compound (II) in a solvent, then add white phosphorus (P4) and react at room temperature or above.

[0035] In the compound of formula (II), M can be an alkali metal or an alkaline earth metal, wherein the alkali metal is preferably lithium, sodium, or potassium, and the alkaline earth metal is preferably calcium or magnesium, and more preferably lithium.

[0036] In reaction step 1-1, the reaction temperature is in the range of room temperature to 50°C, preferably 25°C to 40°C; more preferably 25°C to 35°C; the reaction time is 6 to 24 hours, preferably 10 to 20 hours, more preferably 11 to 18 hours.

[0037] The solvent used in the above reaction is not particularly limited, as long as it is an organic solvent that can dissolve the reactants without reacting with them. Examples include tetrahydrofuran (THF), diethyl ether (Et2O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA). Tetrahydrofuran (THF) and diethyl ether (Et2O) are preferred, and tetrahydrofuran (THF) is more preferred.

[0038] Regarding the ratio of compound (II) to white phosphorus (P4), the ratio of white phosphorus (P4) to compound (II) is 1 to 1.5 molar equivalents, preferably 1.1 to 1.45 molar equivalents, and more preferably 1.2 to 1.4 molar equivalents.

[0039] Step 1-2: Add compound (III) to the reaction mixture obtained in step 1-1 above and allow it to react at room temperature or below.

[0040] In compound (III), R 3 –R 7 Each of these elements is independently hydrogen, alkyl, halogen, C1-C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, or thiophene.

[0041] In a preferred manner, the R 3 –R 7 Each can be independently classified as hydrogen, methyl, methoxy, or phenyl.

[0042] In reaction steps 1-2, the reaction temperature is in the range of 0°C to room temperature; preferably 10°C to room temperature; the reaction time is 0.5 to 6 hours, preferably 1 to 5 hours, and more preferably 2 to 4 hours.

[0043] The solvent used in the above reaction is not particularly limited, as long as it is an organic solvent that can dissolve the reactants without reacting with them. Examples include tetrahydrofuran (THF), diethyl ether (Et2O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA). Tetrahydrofuran (THF) and diethyl ether (Et2O) are preferred, and tetrahydrofuran (THF) is more preferred.

[0044] For the ratio of compound (III) to compound (II), the ratio of compound (III) to compound (II) is 1 to 1.3 molar equivalents, preferably 1.1 to 1.2 molar equivalents.

[0045] Steps 1-3: The reaction system obtained in Step 1-2 is kept in air at room temperature or above to carry out an oxidation reaction, thereby obtaining the acylphosphine oxide compound shown in Formula (I).

[0046] In steps 1-3 of the reaction, the reaction temperature is in the range of room temperature to 40°C, preferably 25°C to 35°C; the oxidation reaction time is 5 to 50 minutes, preferably 10 to 40 minutes, and more preferably 20 to 30 minutes.

[0047] The solvents used in steps 1-1, 1-2, and 1-3 above can be the same or different. For ease of operation and post-processing, it is preferred that the solvents in each step be the same; however, for optimal yield and effect, it is also preferred that the solvents in each step be different.

[0048] In addition, the compound represented by formula (I) of the present invention, namely the acylphosphine oxide compound based on the phosphonium structure, can also be directly used as a free radical photoinitiator and further applied in photocuring technology.

[0049] The effects of the invention

[0050] According to the present invention, an acylphosphine oxide compound based on a phosphonium fluorene structure and its preparation method are provided. Since this reaction uses readily available and inexpensive raw materials such as white phosphorus, acyl chloride, and air for synthesis, it not only eliminates the need for the previously used high-cost diarylphosphine chloride (Ar₂PCl) raw material, but also overcomes the problems of using highly polluting chlorine gas and its subsequent emissions in traditional phosphorus chemical production, making it a more environmentally friendly production method. Furthermore, this invention also pioneers a novel synthetic method for acylphosphine oxide compounds, which features mild reaction conditions, short reaction time, simple post-processing, and high yield, making it a simple, effective, economical, and practical synthetic method.

[0051] The acylphosphine oxide compound based on the phosphonium fluorene structure provided by this invention can be used as a free radical photoinitiator in photocuring technology, and its initiation efficiency can be further improved by adjusting the substituents. Compared with existing technologies, it has the advantages of diverse substituent types, simple synthesis, and high efficiency. Detailed Implementation

[0052] The following specific embodiments further illustrate the above-described contents of the present invention in detail, but should not be construed as limiting the scope of protection of the present invention in any way. All technical solutions implemented based on the above-described contents of the present invention fall within the scope of the present invention. The present invention provides a general and / or specific description of the materials and test methods used in the experiments. Those skilled in the art will understand that, unless otherwise specified, the room temperature mentioned in the following text has a technically known meaning in the art, generally referring to 20–25°C; all chemicals mentioned are commercially available.

[0053] The acylphosphine oxide compound of the present invention is a compound containing a phosphorus fluorene structure as shown in formula (I).

[0054]

[0055] In the acylphosphine oxide compound shown in formula (I) above, R 1 and R 2 They can be the same or different, and can be hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, thiophene.

[0056] Wherein, the R 1 and R 2 Preferably, each of the following can be independently hydrogen, halogen, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl, or C1-C6 alkoxy. The alkyl group is preferably methyl, ethyl, or tert-butyl; the alkoxy group is preferably methoxy or ethoxy; R 1 and R 2 Further preferred groups include hydrogen, methyl, methoxy, tert-butyl, trifluoromethyl, and fluorine.

[0057] R 3 –R 7 Each of these elements is independently hydrogen, halogen, C1-C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, or thiophene.

[0058] Wherein, the R 3 –R 7 Each of the following is an independent preference for hydrogen, methyl, methoxy, and phenyl.

[0059] Preparation of compounds

[0060] The method for preparing the acylphosphine oxide compound of the present invention is a method for preparing the compound containing the phosphatidylfluorene structure shown in formula (I), and the preparation reaction formula is as follows:

[0061]

[0062] The reaction includes the following steps:

[0063] Step 1-1: Dissolve compound (II) in a solvent, then add white phosphorus and react at room temperature or above.

[0064] In the compound of formula (II), M can be an alkali metal or an alkaline earth metal. The alkali metal is lithium, sodium or potassium, and the alkaline earth metal is calcium or magnesium, preferably lithium, sodium or potassium, and more preferably lithium.

[0065] In reaction step 1-1, the reaction temperature is in the range of room temperature to 50°C, preferably 25°C to 40°C; the reaction time is 6 to 24 hours, preferably 10 to 20 hours, and more preferably 11 to 18 hours.

[0066] The solvent used in the above reaction is not particularly limited, as long as it is an organic solvent that can dissolve the reactants without reacting with them. Examples include tetrahydrofuran (THF), diethyl ether (Et2O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA). Tetrahydrofuran (THF) and diethyl ether (Et2O) are preferred, and tetrahydrofuran (THF) is more preferred.

[0067] Regarding the ratio of compound (II) to white phosphorus (P4), the ratio of white phosphorus (P4) to compound (II) is 1 to 1.5 molar equivalents, preferably 1.1 to 1.45 molar equivalents, and more preferably 1.2 to 1.4 molar equivalents.

[0068] Step 1-2: Add compound (III) to the reaction mixture obtained in step 1-2 and react at room temperature or below.

[0069] In compound (III), R 3 –R 7 Each of them is independently hydrogen, halogen, C1 to C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1 to C6 alkoxy, substituted or unsubstituted phenyl, pyridyl or thiophene.

[0070] In a preferred manner, the R 3 –R 7 Each can be independently classified as hydrogen, methyl, methoxy, or phenyl.

[0071] In reaction steps 1-2, the reaction temperature is in the range of 0°C to room temperature, preferably in the range of 10°C to room temperature; the reaction time is 0.5 to 6 hours, preferably 1 to 5 hours, and more preferably 2 to 4 hours.

[0072] The solvent used in the above reaction is not particularly limited, as long as it is an organic solvent that can dissolve the reactants without reacting with them. Examples include tetrahydrofuran (THF), diethyl ether (Et2O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA). Tetrahydrofuran (THF) and diethyl ether (Et2O) are preferred, and tetrahydrofuran (THF) is more preferred.

[0073] For the ratio of compound (III) to compound (II), the ratio of compound (III) to compound (II) is 1 to 1.3 molar equivalents, preferably 1.1 to 1.2 molar equivalents.

[0074] Steps 1-3: The reaction system obtained in Step 1-2 is kept at room temperature or above in air to carry out an oxidation reaction, thereby obtaining the acylphosphine oxide compound of formula (I) of the present invention.

[0075] In reaction steps 1-3, the reaction temperature is in the range of room temperature to 40°C, preferably 25°C to 35°C; the reaction time is 5 to 50 minutes, preferably 10 to 40 minutes, and more preferably 20 to 30 minutes.

[0076] The solvents used in steps 1-1, 1-2, and 1-3 above can be the same or different. For ease of operation and post-processing, it is preferred that the solvents in each step be the same; however, for optimal yield and effect, it is also preferred that the solvents in each step be different.

[0077] As can be seen from the above preparation method, the reactants are readily available, the reaction conditions are very mild, and the reaction time is relatively short. Furthermore, as can be seen from the reaction operations in the examples described later, the post-processing operations are also simple, and a high yield of over 88% can be obtained, which is also economically advantageous. The preparation method of the above-mentioned compounds will be specifically described below through examples.

[0078] Synthesis of compound (I)

[0079] Example 1: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-9-phosphafluorene

[0080]

[0081] At room temperature, 1.0 mmol of 2,2'-dilithium-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, and then 1.1 mmol of white phosphorus was added. After reacting at room temperature for 12 hours, the reaction system became a dark brown solution. Then, 1.1 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was carried out at 15 °C for 3 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 30 °C for 10 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 315 mg of 2,4,6-trimethylbenzoyl-9-oxo-9-phosphafluorene (white solid) was obtained, with a separation yield of 91%.

[0082] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.28(s,3H),2.12(s,6H),6.83(s,2H),7.39(td,J=7.3,3.6 Hz,2H),7.61(t,J=7.6Hz,2H),7.72(t,J=8.3Hz,2H),7.79(dd,J=7.7,2.9Hz,2H); 13 C NMR (126MHz, CDCl3) δ19.6, 21.4, 121.6 (d, J = 9.9Hz), 128.8, 129.3 (d, J = 97.6Hz), 129.5 (d, J = 10.9Hz), 130.8 (d, DEPT 135 (126MHz, CDCl3) δ19.6, 21.4, 121.6 (d, J = 9.8Hz), 128.8, 129.5 (d, J = 11.0Hz), 130.8 (d, J = 9.3Hz), 134.3 (d, J = 2.2Hz); 31 P{ 1 ¹H NMR (202MHz, CDCl₃) δ 28.93.

[0083] Example 2: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-2-methyl-9-phosphafluorene

[0084]

[0085] At room temperature, 1.0 mmol of 2,2'-dilithium-4-methyl-1,1'-biphenyl was added to a 25 mL reaction flask and dissolved in 10 mL of diethyl ether. Then, 1.2 mmol of white phosphorus was added, and the reaction was carried out at 40 °C for 12 hours, resulting in a dark brown solution. Next, 1.1 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was carried out at 5 °C for 5 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at room temperature for 35 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. The solvent was removed by rotary evaporation, yielding 339 mg of 2,4,6-trimethylbenzoyl-9-oxo-2-methyl-9-phosphafluorene (white solid), with a separation yield of 94%.

[0086] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.12(s,6H),2.29(s,3H),2.39(s,3H),6.83(s,2H),7.35(td,J=7.4,3.8Hz,1H),7.41(d,J= 7.8Hz,1H),7.53(d,J=9.5Hz,1H),7.59(t,J=7.6Hz,1H),7.67(dt,J=9.9,4.8Hz,2H),7.75(dd,J=7.7,2.8Hz,1H); 13 C NMR (126MHz, CDCl3) δ19.5, 21.2, 21.3, 121.2 (d, J = 9.9Hz), 121.3 (d, J = 10.5Hz), 1 28.6, 128.8 (d, J = 10.8Hz), 129.5 (d, J = 29.6Hz), 130.6 (d, J = 9.3Hz), 131.2 (d, J = 9. 1Hz),134.1(d,J=2.2Hz),134.3,134.9(d,J=2.2Hz),136.9(d,J=43.0Hz),139.6, 139.7,140.0(d,J=21.3Hz),140.2,142.8(d,J=21.5Hz),216.0(d,J=73.0Hz).DEPT 135(126MHz, CDCl3)δ19.5,21.2,21.3,121.2(d,J=9.8Hz),121.3(d,J=10.4Hz),128.6,128.9( d,J=10.9Hz),130.6(d,J=9.2Hz),131.2(d,J=9.1Hz),134.1(d,J=2.2Hz),134.9(d,J=2.2Hz), 31 P{ 1 ¹H NMR (202MHz, CDCl₃) δ 29.09.

[0087] Example 3: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-2-methoxy-9-phosphafluorene

[0088]

[0089] At room temperature, 1.0 mmol of 2,2'-dilithium-4-methoxy-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of diethyl ether, followed by the addition of 1.1 mmol of white phosphorus. After reacting at room temperature for 15 hours, the reaction system became a dark brown solution. Then, 1.2 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was carried out at 0 °C for 3 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 30 °C for 20 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 346 mg of 2,4,6-trimethylbenzoyl-9-oxo-2-methyl-9-phosphafluorene (white solid) was obtained, with a separation yield of 92%.

[0090] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.11 (s, 6H), 2.28 (s, 3H), 3.80 (s, 3H), 7.12 (d, J = 8.4Hz, 2H), 7.19 (dd, J=10.3,2.1Hz,1H),7.30(td,J=7.5,4.1Hz,1H),7.56(t,J=7.5Hz,1H),7.67(t,J=7.6Hz,3H); 13C NMR (126MHz, CDCl3) δ19.6, 21.3, 55.8, 114.8 (d, J = 10.5Hz), 120.9 (d, J = 10.1Hz), 121.0 (d ,J=2.1Hz),122.8(d,J=11.8Hz),128.3(d,J=11.1Hz),128.5(d,J=98.5Hz),128.7,130.8( d,J=97.2Hz),130.9(d,J=9.4Hz),134.4(d,J=2.2Hz),134.5,135.4(d,J=21.3Hz),136.9( DEPT 135 (126MHz, CDCl3) δ19.6, 21.3, 55.8, 114.8 (d, J = 10.5Hz), 120.9 (d, J = 10.0Hz), 121.0 (d, J = 2. 1Hz), 122.8 (d, J = 11.9Hz), 128.7, 128.3 (d, J = 11.1Hz), 130.9 (d, J = 9.3Hz), 134.4 (d, J = 2.2Hz), 31 P{ 1 H NMR (202MHz, CDCl3) δ 28.81.

[0091] Example 4: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-2,7-di-tert-butyl-9-phosphafluorene

[0092]

[0093] At room temperature, 1.0 mmol of 2,2'-dilithium-4,4'-di-tert-butyl-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, followed by the addition of 1.2 mmol of white phosphorus. After reacting at 35 °C for 16 hours, the reaction system became a dark brown solution. Then, 1.2 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was continued at 5 °C for 6 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air, where it was allowed to react for another 25 minutes at room temperature. After the reaction was complete, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 422 mg of 2,4,6-trimethylbenzoyl-9-oxo-2,7-di-tert-butyl-9-phosphafluorene (white solid) was obtained, with a separation yield of 92%.

[0094] Key NMR data: 1H NMR (400MHz, CDCl3) δ1.30(s,18H),2.05(s,6H),2.26(s,3H),6.80(s,2H),7.55-7.73(m,6H); 13 C NMR (126MHz, CDCl3) δ19.5, 21.3, 31.2, 35.2, 121.0 (d, J = 10.5Hz), 127.9 (d, J = 9.4Hz), 128.7, 128.7 (d, J = 97.8Hz), 131. 4(d,J=2.4Hz),134.3,137.1(d,J=42.8Hz),140.0(d,J=22.2Hz),140.0,152.5(d,J=10.0Hz),216.0(d,J=73.4Hz); 135 (126MHz, CDCl3) δ19.5, 21.3, 31.2, 121.0 (d, J = 10.5Hz), 127.9 (d, J = 9.4Hz), 128.7, 131.4 (d, J = 2.4Hz); 31 P{ 1 ¹H NMR (202MHz, CDCl₃) δ 29.58.

[0095] Example 5: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-2-chloro-9-phosphafluorene

[0096]

[0097] At room temperature, 1.0 mmol of 2,2'-dilithium-4-chloro-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, and then 1.3 mmol of white phosphorus was added. After reacting at room temperature for 18 hours, the reaction system became a dark brown solution. Then, 1.2 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was carried out at 10 °C for 6 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 30 °C for 40 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 335 mg of 2,4,6-trimethylbenzoyl-9-oxo-2-chloro-9-phosphafluorene (white solid) was obtained, with a separation yield of 88%.

[0098] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.13 (s, 6H), 2.30 (s, 3H), 6.86 (s, 2H), 7.41 (td, J = 7.4, 3.9Hz, 1H), 7.57 (d, J = 8.3Hz, 1H), 7.60-7.81 (m, 5H); 13CNMR (126MHz, CDCl3) δ19.7, 21.4, 121.7 (d, J = 9.8Hz), 122.8 (d, J = 10.6Hz), 128.6, 128 .9,129.2(d,J=97.1Hz),129.7(d,J=11.1Hz),130.9(dd,J=18.7,9.9Hz),131.5(d,J=9 5.5Hz),134.2(d,J=2.0Hz),134.5,134.5(d,J=2.2Hz),135.6(d,J=14.3Hz),136.6(d, DEPT 135(126MHz, CDCl3)δ19.7,21.4,121.7(d,J=9.9Hz),122.8(d,J=10.7Hz),128.6,128.9, 129.7(d,J=11.1Hz), 130.9(dd,J=18.7,9.8Hz), 134.2(d,J=2.1Hz), 134.5(d,J=2.1Hz); 31 P{ 1 ¹H NMR (202MHz, CDCl₃) δ 27.66.

[0099] Example 6: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-2-trifluoromethoxy-9-phosphafluorene

[0100]

[0101] At room temperature, 1.0 mmol of 2,2'-dilithium-4-trifluoromethoxy-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of diethyl ether, followed by the addition of 1.2 mmol of white phosphorus. After reacting at 35 °C for 12 hours, the reaction system became a dark brown solution. Then, 1.1 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was continued at 0 °C for 5 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 20 °C for 45 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 392 mg of 2,4,6-trimethylbenzoyl-9-oxo-2-trifluoromethoxy-9-phosphafluorene (white solid) was obtained, with a separation yield of 91%.

[0102] Key NMR data: 1H NMR (400MHz, CDCl3) δ2.12 (s, 6H), 2.29 (s, 3H), 6.85 (s.2H), 7.39-7.48 (m, 2H), 7.52 (d, J = 9.7Hz, 1H), 7.64 (t, J = 7.6Hz, 1H), 7.73-7.86 (m, 3H); 13 CNMR (126MHz, CDCl3) δ19.6, 21.3, 120.5 (q, J = 259.1Hz), 121.8 (d, J = 10.0Hz ),123.1(dd,J=14.2,10.4Hz),126.9,128.6,129.0,129.1,129.8(d,J=11.4 Hz),131.1(d,J=10.0Hz),131.8(d,J=96.4Hz),134.4,134.6,135.7,136.5( d, J=43.4Hz), 140.8, 141.4 (dd, J=43.2, 20.3Hz), 214.7 (d, J=73.7Hz); DEPT 135 (126MHz, CDCl3) δ19.6, 21.3, 121.8 (d, J = 10.0Hz), 123.1 (dd, J = 14.2, 10. 4Hz), 126.9, 128.6, 129.0, 129.8 (d, J = 11.4Hz), 131.1 (d, J = 10.0Hz), 134.6; 31 P{ 1 H NMR (202MHz, CDCl3) δ 27.18; 19 F NMR (471MHz, CDCl3) δ -57.92.

[0103] Example 7: Synthesis of 2,4,6-trimethylbenzoyl-9-oxo-4-fluoro-9-phosphafluorene

[0104]

[0105] At room temperature, 1.0 mmol of 2,2'-dilithium-6-fluoro-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, and then 1.1 mmol of white phosphorus was added. After reacting at 30 °C for 16 hours, the reaction system became a dark brown solution. Then, 1.1 mmol of 2,4,6-trimethylbenzoyl chloride was added, and the reaction was continued at 0 °C for 6 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 20 °C for 50 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 328 mg of 2,4,6-trimethylbenzoyl-9-oxo-4-fluoro-9-phosphafluorene (white solid) was obtained, with a separation yield of 90%.

[0106] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.13 (s, 6H), 2.29 (s, 6H), 6.85 (s, 2H), 7.32 (dd, J = 10.7, 8.3Hz, 1H), 7.41 (tdd, J = 11. 8,5.5,2.5Hz,2H),7.50-7.59(m,1H),7.65(t,J=7.7Hz,1H),7.69-7.77(m,1H),8.10(dd,J=7.8,3.2Hz,1H); 13 C NMR (126MHz, CDCl3) δ19.7, 21.4, 122.1 (dd, J = 21.6, 2.7Hz), 126.3 (dd, J = 11.6, 9.5Hz), 126.7 (dd, J = 8.9, 3.6Hz), 128.9, 129.5 (d, J = 10.6Hz), 130. 7(d,J=9.7Hz),131.1(dd,J=13.0,7.2Hz),131.9(d,J=2.5Hz),132.7(d,J =2.3Hz), 134.5, 134.7 (d, J = 2.3Hz), 136.6 (d, J = 43.8Hz), 139.9 (dd, J = 20. 2, 3.8Hz), 140.7, 158.4 (d, J = 14.3Hz), 160.4 (d, J = 14.3Hz), 215.0 (d, J = 73.2Hz); DEPT135 (126MHz, CDCl3) δ 19.7, 21.4, 122.1 (dd, J = 21.6, 2.7Hz), 1 26.3(dd,J=11.6,9.5Hz),126.7(dd,J=8.9,3.6Hz),128.9,129.5(d,J=10 .6Hz), 130.7(d,J=9.7Hz), 131.1(dd,J=13.0,7.2Hz), 134.7(d,J=2.3Hz); 31 P{ 1 H}NMR (202MHz, CDCl3) δ28.60 (d, J=4.4Hz); 19 F NMR (471MHz, CDCl3) δ-114.83 (d, J=5.0Hz).

[0107] Example 8: Synthesis of 2,6-dimethylbenzoyl-9-oxo-9-phosphafluorene

[0108]

[0109] At room temperature, 1.0 mmol of 2,2'-dilithium-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of diethyl ether, followed by the addition of 1.3 mmol of white phosphorus. After reacting at room temperature for 20 hours, the reaction system became a dark brown solution. Then, 1.1 mmol of 2,6-dimethylbenzoyl chloride was added, and the reaction was continued at 5 °C for 5 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 30 °C for 15 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 312 mg of 2,6-trimethylbenzoyl-9-oxo-9-phosphafluorene (white solid) was obtained, with a separation yield of 94%.

[0110] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.13(s,6H),7.00(d,J=7.6Hz,2H),7.21(t,J=7.6Hz,1H),7.39(td,J =7.4,3.7Hz,2H),7.62(t,J=7.6Hz,2H),7.72(t,J=8.3Hz,2H),7.80(dd,J=7.7,2.9Hz,2H); 13 C NMR (126MHz, CDCl3) δ19.7, 121.7 (d, J = 9.9Hz), 128.0, 129.1 (d, J = 98.0Hz), 129.5 (d, J = 10.9Hz), 130.3, 130.9 DEPT 135 (126MHz, CDCl3) δ19.7, 121.7 (d, J = 9.9Hz), 128.0, 129.5 (d, J = 10.9Hz), 130.3, 130.9 (d, J = 9.2Hz), 134.4 (d, J = 2.2Hz); 31 P{ 1 ¹H NMR (202MHz, CDCl₃) δ 28.90.

[0111] Example 9: Synthesis of 2,6-dimethylbenzoyl-9-oxo-2-methyl-9-phosphafluorene

[0112]

[0113] At room temperature, 1.0 mmol of 2,2'-dilithium-4-methyl-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, and then 1.1 mmol of white phosphorus was added. After reacting at 40 °C for 15 hours, the reaction system became a dark brown solution. Then, 1.1 mmol of 2,6-dimethylbenzoyl chloride was added, and the reaction was continued at 0 °C for 3 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air. The reaction was continued at 40 °C for 40 minutes. After the reaction was completed, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. After removing the solvent by rotary evaporation, 329 mg of 2,6-dimethylbenzoyl-9-oxo-2-methyl-9-phosphafluorene (white solid) was obtained, with a separation yield of 95%.

[0114] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.12(s,6H),2.38(s,3H),7.00(d,J=7.6Hz,2H),7.21(t,J=7.6Hz,1H),7.34(td,J=7.4,3.7Hz,1H),7. 41(d,J=7.9Hz,1H),7.52(d,J=9.5Hz,1H),7.58(t,J=7.6Hz,1H),7.66(dt,J=10.1,4.9Hz,2H),7.74(dd,J=7.7,3.0Hz,1H); 13 C NMR (126MHz, CDCl3) δ19.6, 21.4, 121.3 (d, J = 9.9Hz), 121.5 (d, J = 10.5Hz), 127.9, 128.5 (d,J=29.6Hz),129.0(d,J=11.0Hz),129.3(d,J=29.8Hz),130.2,130.9(d,J=9.2Hz),13 1.5(d,J=9.1Hz),134.3(d,J=2.3Hz),134.4,135.1(d,J=2.3Hz),139.7(d,J=42.6Hz),1 39.8(d,J=10.8Hz), 140.1(d,J=21.6Hz), 142.9(d,J=21.7Hz), 215.9(d,J=73.2Hz); DEPT 135(126MHz, CDCl3)δ19.6,21.4,121.3(d,J=9.9Hz),121.5(d,J=10.5Hz),127.9,129.0(d,J=1 1.0Hz), 130.2, 130.9 (d, J = 9.2Hz), 131.5 (d, J = 9.1Hz), 134.3 (d, J = 2.2Hz), 135.1 (d, J = 2.3Hz), 31 P{1 ¹H NMR (202MHz, CDCl₃) δ 29.08.

[0115] Example 10: Synthesis of 2,6-dimethylbenzoyl-9-oxo-2-trifluoromethoxy-9-phosphafluorene

[0116]

[0117] At room temperature, 1.0 mmol of 2,2'-dilithium-4-trifluoromethoxy-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of diethyl ether, followed by the addition of 1.2 mmol of white phosphorus. After reacting at 35 °C for 12 hours, the reaction system became a dark brown solution. Then, 1.2 mmol of 2,6-dimethylbenzoyl chloride was added, and the reaction was continued at 10 °C for 4 hours. The rubber stopper of the reaction flask was opened, and the flask was placed in air, where it was allowed to react for another 30 minutes at room temperature. After the reaction was complete, the flocculent matter was removed by filtration. The reaction solvent was concentrated and separated by column chromatography using a petroleum ether / ethyl acetate mixture. The solvent was removed by rotary evaporation, yielding 354 mg of 2,6-dimethylbenzoyl-9-oxo-2-trifluoromethoxy-9-phosphafluorene (white solid), with a separation yield of 85%.

[0118] Key NMR data: 1 H NMR (400MHz, CDCl3) δ2.13(s,6H),7.02(d,J=7.6Hz,2H),7.23(t,J=7.7Hz,1H),7.44(d t,J=10.7,4.9Hz,2H),7.53(d,J=9.6Hz,1H),7.65(t,J=7.6Hz,1H),7.73-7.87(m,3H); 13C NMR (126MHz, CDCl3) δ19.6, 120.4 (q, J = 259.0Hz), 121.9 (d, J = 9.9Hz), 123.1 (d, J = 11.1Hz), 123.2 (d, J = 10.4Hz), 127.0, 128.1, 128.8, 129.6, 129.8 (d, J = 11.2Hz), 130.6, 131.2 (d, J = 9.3Hz), 131.5 (d, J = 96.0Hz), 134.3, 134.7 (d, J = 2.2Hz), 139.1 (d, J = 43. 6Hz), 141.3 (d, J = 37.4, 20.5Hz), 149.8 (d, J = 15.4Hz), 214.6 (d, J = 73.2Hz); DEPT135 (126MHz, CDCl3) δ 19.6, 121.9 (d, J = 9.9Hz) ,123.1(d,J=11.1Hz),123.2(d,J=10.4Hz),127.0,128.1,129.8(d,J=11.2Hz),130.6,131.2(d,J=9.3Hz),134.7(d,J=2.2Hz); 31 P{ 1 H NMR (202MHz, CDCl3) δ 27.23; 19 F NMR (471MHz, CDCl3) δ -57.89.

[0119] Industry availability

[0120] The acylphosphine oxide compound based on the phosphonium structure of the present invention has broad application prospects as a free radical photoinitiator in photocuring technology.

Claims

1. A method for preparing an acylphosphine oxide compound, which is a method for preparing a compound containing a phosphatene structure as shown in formula (I) below. In equation (I), R 1 and R 2 They may be the same or different, each independently being hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl, C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, or thiophene; R 3 –R 7 Each of them is independently hydrogen, halogen, C1-C6 alkyl, C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridyl, or thiophene; The preparation method includes the following steps: Step 1-1: Dissolve compound (II) in a solvent, then add white phosphorus and allow the reaction to occur at room temperature or above. In compound (II), M represents lithium, an alkali metal. R 1 and R 2 Same as formula (I); the ratio of the compound of formula (II) used to white phosphorus is 1 to 1.5 molar equivalents; Step 1-2: Add compound (III) to the reaction mixture obtained in Step 1-1, and continue the reaction below room temperature. In compound (III), R 3 –R 7 Same as equation (I); The ratio of the compound of formula (III) to the compound of formula (II) is 1 to 1.2 molar equivalents; Steps 1-3: The reaction system obtained in step 1-2 is kept in air at room temperature or above to carry out an oxidation reaction, thereby obtaining the acylphosphine oxide compound shown in formula (I).

2. The method for preparing the acylphosphine oxide compound according to claim 1, characterized in that, In step 1-1, the reaction temperature is from room temperature to 50°C, and the reaction time is 6 to 24 hours. In steps 1-2, the reaction temperature is within the range of 0℃ to room temperature, and the reaction time is 0.5 to 6 hours. In steps 1-3, the reaction temperature is from room temperature to 40°C, and the oxidation reaction time is 5 to 50 minutes.

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