Preparation method of novel disubstituted oxygen / thioxanthone efficient visible light initiator and application of novel disubstituted oxygen / thioxanthone efficient visible light initiator in acrylate photopolymerization system
By preparing novel disubstituted oxygen/thio-heterocyclic anthrone photoinitiators, the problem of odor or toxicity generated by oxygen/thio-heterocyclic anthrone photoinitiators during tertiary amine migration was solved, improving photoinitiation efficiency and stability, and achieving highly efficient photocuring effect.
Patent Information
- Application Number
- CN202411327417.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-05-22
- Filing Date
- 2024-09-23
- Publication Date
- 2025-11-25
AI Technical Summary
Existing oxo/thioxanthones photoinitiators generate odor or toxicity issues during tertiary amine migration and have poor stability in polymer films, affecting the curing rate and extent of photocurable materials.
A novel class of disubstituted oxygen/thioheterocyclic anthrone photoinitiators was designed. By reacting 2,4-disubstituted oxygen/thioheterocyclic anthrone compounds with acyl chloride compounds, a novel photoinitiator with acyl functional groups was prepared for use in acrylate-based free radical photopolymerization systems.
It improves photoinitiation efficiency, enhances solubility in organic solvents and resins, and efficiently initiates free radical monomer polymerization under ultraviolet LED light irradiation, achieving a conversion efficiency of over 65%, thus broadening its application range.
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Figure CN121005676A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a kind of novel double-substituted oxygen / sulfur heteroanthracene ketone class efficient visible light initiator preparation method and its application in acrylate photopolymerization system, belong to free radical photoinitiator field. BACKGROUND
[0002] Photocuring technology is a kind of green environmental protection technology, is widely used in coatings, inks, electronic communication, photoresist, dental materials and 3D printing and other fields. Since visible light curing technology and visible light LED light source have the advantages of light source stability, environmental protection and safety, it is of great significance to develop new visible light initiator. As an important component of visible light curing system, visible light initiator has a significant impact on the curing rate and curing degree of photocuring material.
[0003] Oxygen / sulfur heteroanthracene ketone is a common carbonyl-containing photoinitiator, due to its low triplet energy and high quantum yield, its main absorption wavelength is in the range of 370-385 nm, and its edge can extend to about 420 nm. Therefore, it is easy to match the emission spectrum of light source by adjusting the absorption spectrum, and has great development and application potential. Oxygen / sulfur heteroanthracene ketone belongs to the typical hydrogen abstraction type (Type II) photoinitiator, which usually needs external tertiary amine, thiol and other hydrogen donors. Since the migration ability of small molecule tertiary amine is strong, it is easy to produce odor or toxicity problem. In order to solve this problem, ether bond, sulfide bond is usually introduced into oxygen / sulfur heteroanthracene ketone skeleton molecule, forming multifunctional single-component oxygen / sulfur heteroanthracene ketone visible light initiator which integrates photosensitizer and hydrogen donor. This kind of photoinitiator not only has high efficient visible light initiation effect, and its stability in polymer film is stronger. Therefore, as a kind of efficient photoinitiator, oxygen / sulfur heteroanthracene ketone derivative is widely used in free radical and cationic photopolymerization technology. SUMMARY
[0004] The present application takes disubstituted oxygen / sulfur heterocyclic anthracene ketone as the basic conjugated skeleton structure, combines with functional acyl functional group, and designs a kind of novel disubstituted oxygen / sulfur heterocyclic anthracene ketone visible light initiator. This kind of visible light initiator has excellent light absorption performance in ultraviolet-visible light region, and shows high efficient initiation effect on acrylate-containing free radical photopolymerization system.
[0005] The purpose of the present application is achieved by the following scheme: The preparation method of novel double-substituted oxygen / sulfur heterocyclic anthracene ketone class efficient visible light initiator uses 2,4-disubstituted oxygen / sulfur heterocyclic anthracene ketone compound and acyl chloride compound as raw materials, and adopts the synthesis route shown in the following formula.
[0006]
[0007] The preparation method includes the following steps: Under inert gas protection, 2,4-disubstituted oxygen / thiocyclic anthrone compounds were dissolved in an organic solvent, and an excess of alkali was added. An excess organic solution of the acyl chloride compound was slowly added dropwise under an ice-water bath. The reaction was carried out at room temperature, and TLC analysis confirmed complete reaction. The reaction was then stopped. The mixture was filtered, the filtrate was concentrated, and purified to obtain a novel, highly efficient visible-light initiator of disubstituted heterocyclic anthrone compounds.
[0008] The 2,4-disubstituted oxy / thioheterocyclic anthrone compounds include, but are not limited to: .
[0009] Where R 1 and R 2 It is oxygen or sulfur; The sulfonyl chloride compound is: R 3 COCl, R 3 Includes, but is not limited to, one of the following groups: ; Where R 4 For oxygen or sulfur; R 5 For nitrogen or phosphorus; R 6 It can be methyl or ethyl.
[0010] The solvents include, but are not limited to, ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or N,N-dimethylacetamide; the bases include, but are not limited to, sodium hydroxide (NaOH), potassium hydroxide (KOH), pyridine, triethylamine ((C2H5)3N), piperidine or pyrrolidine.
[0011] In the preparation method described above, the reactions in each step are carried out at room temperature.
[0012] A novel class of highly efficient visible light initiators, derived from disubstituted oxygen / thioheterocyclic anthrones, prepared using the above method, has the following specific structural formula:
[0013] in: R 1 and R 2 It is oxygen or sulfur; R 3 Includes, but is not limited to, one of the following groups: ; R 4 It is oxygen or sulfur; R 5 It is nitrogen or phosphorus; R 6 It can be methyl or ethyl.
[0014] In some preferred embodiments, the structure of the photoinitiator is selected from... , , , , ,or Any one of them.
[0015] The novel disubstituted oxygen / thiocyclic anthrone-based high-efficiency visible light initiator can be applied to initiate and cure acrylate-containing free radical photopolymerization systems of prepolymers. The acrylate-containing prepolymer polymerization system includes any one of the following acrylate-based HDDA, TPGDA, DPGDA, NPGDA, TEGDA, and PDDA systems.
[0016] These novel, bisubstituted oxygen / thioheterocyclic anthrone-based high-efficiency visible light initiators not only exhibit better solubility in organic solvents and resins, but also demonstrate higher polymerization efficiency in photocuring systems, thus broadening their application range in free radical photocuring systems.
[0017] The advantages and beneficial effects of this invention are as follows: High photoinitiation efficiency. Photopolymerization kinetics studies of this invention show that the novel disubstituted oxygen / thioheterocyclic anthrone-based high-efficiency visible light initiator can efficiently initiate free radical monomer polymerization under ultraviolet LED light irradiation. The initiation conversion efficiency of the visible light initiator for the acrylate-containing polymerization system is 65% or higher, more preferably 75% or higher, more preferably 80% or higher, more preferably 90% or higher, and more preferably 95% or higher. Attached Figure Description
[0018] Figure 1 The FT-IR spectrum of 2,4-bis(acetoxy)thioxanthonone prepared in Example 1.
[0019] Figure 2 The 2,4-bis(acetoxy)thioxanthonone prepared in Example 1 1 H-NMR spectrum.
[0020] Figure 3 The 2,4-bis(acetoxy)thioxanthonone prepared in Example 1 13 C-NMR spectrum.
[0021] Figure 4 The UV-vis spectrum of 2,4-bis(acetoxy)thionone prepared in Example 1.
[0022] Figure 5The kinetic curve of HDDA initiated by 2,4-bis(acetoxy)thionanone prepared in Example 1. Detailed Implementation
[0023] The features and advantages of the present invention can be further understood through the following detailed description in conjunction with the accompanying drawings. The provided embodiments are merely illustrative of the method of the present invention and do not limit the rest of the content disclosed herein in any way.
[0024] Example 1. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthrone, 2.50 g (25 mmol) of triethylamine, and 40 mL of anhydrous tetrahydrofuran were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of freshly distilled tetrahydrofuran and 0.20 g (25 mmol) of chloroacetyl were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 3 g of the target compound 1.
[0025] Figures 1-3 The provided FT-IR, 1 H and 13 C10 NMR provided evidence for the structure of target compound 1.
[0026] Appendix Figure 1 The FT-IR spectra appear at 2970 and 2921 cm⁻¹. -1 The absorption peak can be attributed to the characteristic absorption peak of the CH stretching vibration on the benzene ring skeleton in its molecular structure; 1721 cm⁻¹ -1 and 1635 cm -1 The absorption peaks at 1601 and 1437 cm⁻¹ can be attributed to the stretching vibrations of the ester carbonyl group of the acetate ester and the ketone carbonyl group of the thioxanthone in its molecular structure; -1 The characteristic absorption peak for the C=C stretching vibration of the anthracene ring skeleton is located at 1268 cm⁻¹. -1 The peak at this location represents the characteristic peak of the COC stretching vibration of the acetate group.
[0027] Depend on Figure 2 As can be seen, the proton peaks of the benzene ring skeleton near both sides of the acetoxy group are at chemical shifts of 8.2 and 7.4 ppm, the proton peaks of the benzene ring skeleton on the thioxanthone are in the range of 7.4-7.7 ppm, and the proton peaks of the methyl group on the disubstituted acetoxy group are at 2.5 and 2.4 ppm.
[0028] Figure 3The data shows that the chemical shift at 173.9 ppm is the C=O carbon peak in the thioxanthone structure, the peaks at 163.2 and 164.2 ppm are the O=C carbon peaks in the disubstituted acetoxy group, the peaks at 143.7 and 141.2 ppm are the resonance absorption peaks of the two C atoms bonded to the adjacent ether bond in the thioxanthone structure, and the peaks at 16.2 and 16.1 ppm are the methyl absorption peaks in the disubstituted acetoxy group. These results indicate that the target compound 1 has been successfully prepared.
[0029] from Figure 4 The UV-vis spectrum shows that the maximum absorption wavelength of target compound 1 is located at 405 nm, which is in the visible light region, and the effective absorption range covers 275-450 nm.
[0030] Appendix Figure 5 The kinetic curves for inducing HDDA are presented. The change in absorption intensity of a characteristic peak under illumination was recorded using real-time infrared spectroscopy and a high-speed recorder. Using HDDA as the monomer, different concentrations of target compound 1 ([PI] = 2 × 10⁻⁶) were prepared. -5 A mol / g HDDA sample solution was dropped into the middle of a potassium bromide salt sheet to form a uniform liquid film. After 15 min of LED UV irradiation, the change in the carbon-carbon double bond absorption peak area was recorded using an infrared spectrometer to obtain the conversion rate of the corresponding monomer. The results show that 2,4-di(acetoxy)thioxanthanone can also successfully initiate the free radical polymerization of polyurethane acrylic resins. These photopolymerization experimental results demonstrate that 2,4-di(acetoxy)thioxanthanone is an excellent visible light initiator.
[0031] Example 2. Visible light initiator Preparation 2.60 g (10 mmol) of 2,4-dimercaptoxanthone, 1.00 g (25 mmol) of sodium hydroxide, and 40 mL of anhydrous ethanol were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of anhydrous ethanol and 0.24 g (25 mmol) of chloropropionyl were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 3.7 g of the target compound 2.
[0032] Kinetic application testing of acrylate-based TPGDA using compound 2: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. Using TPGDA as the polymerization monomer, target compound 2 ([PI] = 2 × 10⁻⁶) was added.-5 A mol / g TPGDA sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomer TPGDA was detected to be 68%.
[0033] Example 3. Visible light initiator Preparation 2.60 g (10 mmol) of 2,4-dimercaptoxanthone, 0.20 g (25 mmol) of pyridine, and 40 mL of anhydrous acetone were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of anhydrous acetone and 0.33 g (25 mmol) of furan-2-formyl chloride were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 4.91 g of the target compound 3.
[0034] Kinetic application testing of acrylate DPGDA initiated by compound 3: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. DPGDA was used as the polymerization monomer, and target compound 3 ([PI] = 2 × 10⁻⁶) was added. -5 A mol / g DPGDA sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomer DPGDA was detected to be 90%.
[0035] Example 4. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthrone, 0.21 g (25 mmol) of piperidine, and 40 mL of anhydrous acetonitrile were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of freshly distilled acetonitrile and 0.37 g (25 mmol) of thiophene-2-formyl chloride were slowly added dropwise over a constant-pressure dropping funnel over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 4.64 g of the target compound 4.
[0036] Kinetic application testing of compound 4-initiated NPGDA acrylate: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. Using NPGDA as the polymerization monomer, target compound 4 ([PI] = 2 × 10⁻⁶) was added. -5 A sample solution of NPGDA (mol / g) was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomer NPGDA was found to be 86%.
[0037] Example 5. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthone, 0.18 g (25 mmol) of tetrahydropyrrole, and 40 mL of N,N-dimethylformamide were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of N,N-dimethylformamide and 0.36 g (25 mmol) of N-methylpyrrole-2-formyl chloride were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 4.58 g of the target compound 5.
[0038] Kinetic application testing of acrylate-based TEGDA initiated by compound 5: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. Using TEGDA as the polymerization monomer, target compound 5 ([PI] = 2 × 10⁻⁶) was added. -5 A mol / g TEGDA sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomer TEGDA was detected to be 72%.
[0039] Example 6. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthrone, 0.14 g (25 mmol) of potassium hydroxide, and 40 mL of N,N-dimethylacetamide were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of N,N-dimethylacetamide and 0.44 g (25 mmol) of P-methylphosphacyclopentadiene-2-carboxyl chloride were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 5.20 g of the target compound 6.
[0040] The kinetics of acrylate-based PDDA were tested using compounds 1-6 prepared above: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. Using PDDA as the monomer, target compound 1-6 ([PI] = 2 × 10⁻⁶) was added. -5 A mol / g PDDA sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the changes in the carbon-carbon double bond absorption peak area were recorded using an infrared spectrometer. The conversion rate distribution of PDDA monomers is as follows: .
Claims
1. A method for preparing the visible light initiator described above, characterized in that, The preparation method includes the following steps: Under inert gas protection, 2,4-disubstituted oxygen / thiocyclic anthrone compounds were dissolved in an organic solvent, excess alkali was added, and excess organic solution of acyl chloride compounds was slowly added dropwise under an ice-water bath. The reaction was carried out at room temperature, and the reaction was stopped by TLC detection. The mixture was then filtered, the filtrate was concentrated, and purified to obtain a novel, highly efficient visible light initiator of disubstituted heterocyclic anthrone compounds.
2. The method for preparing the visible light initiator according to claim 1, characterized in that, The 2,4-disubstituted oxygen / thioheterocyclic anthrone compounds include the following compounds: R 1 For oxygen or sulfur; R 2 It is oxygen or sulfur.
3. The method for preparing the visible light initiator according to claim 2, characterized in that, The acyl chloride compound is R 3 C(O)Cl, R 3 Includes one of the following groups: ;R 4 For oxygen or sulfur; R 5 For nitrogen or phosphorus; R 6 It can be methyl or ethyl.
4. The method for preparing the visible light initiator according to claim 3, characterized in that, The organic solvent includes any one of ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, N,N-dimethylformamide, or N,N-dimethylacetamide.
5. The method for preparing the visible light initiator according to claim 4, characterized in that, The bases mentioned include, but are not limited to, sodium hydroxide, potassium hydroxide, pyridine, triethylamine, piperidine, or tetrahydropyrrole.
6. The photoinitiator prepared by the method for preparing a visible light initiator according to any one of claims 1-5, characterized in that, The visible light initiator has an oxygen / thioxanthrone as its main skeleton, and its structural formula is as follows: ;R 1 For oxygen or sulfur; R 2 For oxygen or sulfur; R 3 Includes, but is not limited to, one of the following groups: ;R 4 For oxygen or sulfur; R 5 For nitrogen or phosphorus; R 6 It can be methyl or ethyl.
7. The visible light initiator according to claim 6, characterized in that: The structure of the photoinitiator is selected from... , , , , ,or Any one of them.
8. The visible light initiator prepared by the method of any one of claims 1-5 or the visible light initiator of claim 6 or 7, used as a photo-acid-generating agent molecule in a prepolymer containing acrylate free radical photopolymerization system, is a photoinitiator.
9. The application according to claim 8, characterized in that, The prepolymer containing acrylate polymerization system includes any one of the acrylate HDDA, TPGDA, DPGDA, NPGDA, TEGDA, and PDDA systems.