阅读说明：本技术 一种基于高级脂肪酸的夺氢型光引发剂的制备方法及其产品 (Preparation method of higher fatty acid-based hydrogen abstraction type photoinitiator and product thereof ) 是由 李经方 周贤菊 谢广新 于 2021-10-22 设计创作，主要内容包括：本发明涉及一种基于高级脂肪酸的夺氢型光引发剂的制备方法及其产品,属于光引发剂制备技术领域。本发明的夺氢型光引发剂的制备方法是在乙烯酮夺氢型光引发剂的结构基础上引入高级脂肪酸长烃基链,在乙烯酮光引发剂结构中引入高级脂肪酸长烃基链既能够增大光引发剂的极性,提高光引发剂与预聚物的相容性；也能够增大光引发剂的分子量,防止光固化反应结束后,残留光引发剂从固化膜中迁出,造成毒性和气味。由于长烃基链不参与光引发剂共轭,光引发剂的最大吸收波长位于350～450nm,可与紫外蓝光LED相匹配,这种具有与光固化体系相容性好,低迁移效果的夺氢型光引发剂符合光固化领域中的需求。(The invention relates to a preparation method of a hydrogen abstraction type photoinitiator based on higher fatty acid and a product thereof, belonging to the technical field of preparation of photoinitiators. The preparation method of the hydrogen abstraction type photoinitiator introduces a high-grade fatty acid long hydrocarbyl chain on the basis of the structure of the ketene hydrogen abstraction type photoinitiator, and the introduction of the high-grade fatty acid long hydrocarbyl chain in the structure of the ketene photoinitiator can increase the polarity of the photoinitiator and improve the compatibility of the photoinitiator and a prepolymer; the molecular weight of the photoinitiator can be increased, and the residual photoinitiator is prevented from migrating out of a cured film after the photocuring reaction is finished, so that toxicity and odor are prevented. Because the long hydrocarbyl chain does not participate in the conjugation of the photoinitiator, the maximum absorption wavelength of the photoinitiator is 350-450 nm and can be matched with an ultraviolet blue LED, and the hydrogen abstraction type photoinitiator has good compatibility with a photocuring system and low migration effect and meets the requirements in the field of photocuring.)

1. A preparation method of a higher fatty acid-based hydrogen abstraction photoinitiator is characterized by comprising the following steps:

adding the intermediate product and an aromatic aldehyde compound into an organic solvent for dissolving, taking an alkali solution as a catalyst, adjusting the pH value to 8-12, reacting at room temperature for 3-5 hours in a protective gas in a dark condition, then continuing an ice-water bath reaction until a light yellow crystal is separated out, washing with deionized water, and performing vacuum drying to obtain the higher fatty acid-based hydrogen abstraction photoinitiator;

the intermediate product is prepared according to any one of the following methods:

the method comprises the following steps: reacting higher fatty acid and hydroxyl ketone containing alpha-H in an organic solvent for 1-5 hours at 60-200 ℃ under the catalysis of concentrated sulfuric acid, continuously adding sodium carbonate after the reaction is finished, extracting and separating, and washing with water to obtain an intermediate product;

the second method comprises the following steps: reacting higher fatty acyl chloride with hydroxy ketone containing alpha-H under the action of triethylamine, adjusting the pH value to be neutral, and separating and purifying to obtain the product.

2. The production method according to claim 1, wherein the reaction formula of the production method is any one of the following reaction formulas:

reaction formula one

Reaction formula II

Reaction formula III

Reaction type IV

Reaction formula five

Wherein R is₁Is a hydrocarbyl moiety of a higher fatty acid;

R₂、R₄independently selected from any one of alkyl with 1-24 carbon atoms, alkoxy with 1-24 carbon atoms or alkenyl with 1-24 carbon atoms, R₂、R₄Independently selected from any one of alkyl, alkoxy or alkenyl with 1-24 carbon atoms and taking hydroxyl, halogen, nitryl, sulfonic group, cyano-group, imino, aryl or heterocyclic aryl as substituent;

R₃independently selected from aryl or heterocyclic aryl, R₃Independently selected from an aryl group or a heterocyclic aryl group substituted by hydroxyl, halogen, nitro, sulfonic group, cyano, imino, alkyl with 1-24 carbon atoms, alkoxy with 1-24 carbon atoms and alkenyl with 1-24 carbon atoms.

3. The preparation method according to claim 1, wherein the molar ratio of the higher fatty acid to the alpha-H-containing hydroxyketone in the first method is 1:1 to 2, mol: L, and the addition amount of the concentrated sulfuric acid is 1 wt%;

the higher fatty acid includes, but is not limited to, any one or more of hexadecanoic acid, heptadecanoic acid, octadecanoic acid, octadecenoic acid, octadecadienoic acid, octadecatrienoic acid, eicosanoic acid, eicosapentaenoic acid, docosanoic acid, docosahexenyl or tetracosanoic acid.

4. The preparation method according to claim 1, wherein in the second method, the molar ratio of the higher fatty acid chloride to the hydroxyl ketone containing alpha-H is 1: 1-2, mol: L, and the mass of the triethylamine or the triethanolamine is 5-10% of the mass of the higher fatty acid chloride;

the higher fatty acyl chloride includes, but is not limited to, any one or more of hexadecanoyl chloride, heptadecanoyl chloride, octadecanoyl chloride, octadecenoyl chloride, octadecadienoyl chloride, octadecatrienoyl chloride, eicosanoyl chloride, eicosapentaenoic acid chloride, docosanoyl chloride or tetracosanoyl chloride.

5. The preparation method according to claim 1, wherein the molar ratio of the intermediate product to the aromatic aldehyde compound is 1: 1-2 mol: L.

6. The method according to claim 5, wherein the aromatic aldehyde compound comprises any one of an aromatic aldehyde, an aromatic aldehyde substituent, a heterocyclic aromatic aldehyde, or a heterocyclic aromatic aldehyde substituent.

7. The preparation method according to claim 1, wherein the organic solvent comprises any one or more of methanol, ethanol, ethyl acetate, dichloromethane, chloroform or acetonitrile; the protective gas is nitrogen.

8. The method according to claim 1, wherein the alkali solution is any one of ammonia water, sodium hydroxide, potassium hydroxide, or sodium bicarbonate.

9. A higher fatty acid-based hydrogen abstraction photoinitiator produced by the production method of any one of claims 1 to 8.

10. Use of a hydrogen abstraction photoinitiator according to claim 9 in the preparation of a photocurable formulation.

Technical Field

The invention belongs to the technical field of photoinitiator preparation, and relates to a preparation method of a higher fatty acid-based hydrogen abstraction type photoinitiator and a product thereof.

Background

The photocuring technology is widely applied to the fields of coatings, printing ink, adhesives, photoresists and the like because of the advantages of high curing speed, energy conservation, environmental protection and the like. The photocurable formulation generally includes a prepolymer, a photoinitiator, and a diluent. The photoinitiator serves as a key component in the photocurable formulation and plays a role in determining the degree of polymerization of the prepolymer. The ketene photoinitiator is a hydrogen abstraction type photoinitiator which is simple to prepare and low in price, has rich scientific research value and has good photoinitiation performance; however, the ketene photoinitiator molecules have a very strong rigid structure, and the structure not only can cause poor compatibility between the ketene photoinitiator molecules and the pre-polymer, but also can reduce the photoinitiation performance of the ketene photoinitiator, thereby limiting the application value of the ketene photoinitiator molecules in the photocuring formula.

With the development of science and technology, the photoinitiator is required to have excellent photoinitiation performance, low mobility, low toxicity, environmental friendliness and the like. The ketene photoinitiators reported at present and most ultraviolet photoinitiators belong to small molecules, and after the photocuring reaction is finished, the residual ketene photoinitiators can cause the problem of emigration, so that odor and toxicity are generated.

Therefore, the development of ketene photoinitiators with good compatibility with prepolymers and low toxicity is a problem to be solved.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a method for preparing a higher fatty acid-based hydrogen abstraction photoinitiator; the second purpose of the present invention is to provide a higher fatty acid-based hydrogen abstraction photoinitiator; the invention also aims to provide the application of the higher fatty acid-based hydrogen abstraction photoinitiator in preparing the photocuring formula.

In order to achieve the purpose, the invention provides the following technical scheme:

1. a preparation method of a higher fatty acid-based hydrogen abstraction photoinitiator, comprising the following steps:

adding the intermediate product and an aromatic aldehyde compound into an organic solvent for dissolving, taking an alkali solution as a catalyst, adjusting the pH value to 8-12, reacting at room temperature for 3-5 hours in a protective gas in a dark condition, then continuing an ice-water bath reaction until a light yellow crystal is separated out, washing with deionized water, and performing vacuum drying to obtain the higher fatty acid-based hydrogen abstraction photoinitiator;

the intermediate product is prepared according to any one of the following methods:

the method comprises the following steps: reacting higher fatty acid and hydroxyl ketone containing alpha-H in an organic solvent for 1-5 hours at 60-200 ℃ under the catalysis of concentrated sulfuric acid, continuously adding sodium carbonate after the reaction is finished, extracting and separating, and washing with water to obtain an intermediate product;

the second method comprises the following steps: reacting higher fatty acyl chloride with hydroxy ketone containing alpha-H under the action of triethylamine, adjusting the pH value to be neutral, and separating and purifying to obtain the product.

Preferably, the reaction formula of the preparation method is any one of the following reaction formulas:

reaction formula one

Reaction formula II

Reaction formula III

Reaction type IV

Reaction formula five

Wherein R is₁Is a hydrocarbyl moiety of a higher fatty acid;

R₂、R₄independently selected from any one of alkyl with 1-24 carbon atoms, alkoxy with 1-24 carbon atoms or alkenyl with 1-24 carbon atoms, R₂、R₄Independently selected from any one of alkyl, alkoxy or alkenyl with 1-24 carbon atoms and taking hydroxyl, halogen, nitryl, sulfonic group, cyano-group, imino, aromatic group or heterocyclic aromatic group as a substituent;

R₃independently selected from aryl or heterocyclic aryl, R₃Independently selected from an aryl group or a heterocyclic aryl group substituted by hydroxyl, halogen, nitro, sulfonic group, cyano, imino, alkyl with 1-24 carbon atoms, alkoxy with 1-24 carbon atoms and alkenyl with 1-24 carbon atoms.

Preferably, in the first method, the molar ratio of the higher fatty acid to the alpha-H-containing hydroxyketone is 1: 1-2, mol: L, and the addition amount of the concentrated sulfuric acid is 1 wt%;

the higher fatty acid includes, but is not limited to, any one or more of hexadecanoic acid, heptadecylic acid, octadecanoic acid, octadecenoic acid, octadecadienoic acid, octadecatrienoic acid, eicosanoic acid, eicosapentaenoic acid, docosanoic acid, docosahexenyl or tetracosanoic acid.

Preferably, in the second method, the molar ratio of the higher fatty acyl chloride to the hydroxyl ketone containing alpha-H is 1: 1-2, the mol: L is, and the mass of the triethylamine or the triethanolamine is 5-10% of that of the higher fatty acyl chloride;

the higher fatty acyl chloride includes, but is not limited to, any one or more of hexadecanoyl chloride, heptadecanoyl chloride, octadecanoyl chloride, octadecenoyl chloride, octadecadienoyl chloride, octadecatrienoyl chloride, eicosanoyl chloride, eicosapentaenoic acid chloride, docosanoyl chloride or tetracosanoyl chloride.

Preferably, the molar ratio of the intermediate product to the aromatic aldehyde compound is 1: 1-2, and the mol: L is.

More preferably, the aromatic aldehyde compound includes any one of an aromatic aldehyde, an aromatic aldehyde substituent, a heterocyclic aromatic aldehyde, or a heterocyclic aromatic aldehyde substituent.

Preferably, the organic solvent comprises one or more of methanol, ethanol, ethyl acetate, dichloromethane, chloroform or acetonitrile; the protective gas is nitrogen.

More preferably, the alkali solution is any one of ammonia water, sodium hydroxide, potassium hydroxide or sodium bicarbonate.

2. The higher fatty acid-based hydrogen abstraction photoinitiator prepared according to the above preparation method.

3. The hydrogen abstraction photoinitiator is applied to the preparation of a photocuring formula.

The invention has the beneficial effects that:

1. the invention discloses a preparation method of a hydrogen abstraction type photoinitiator based on higher fatty acid, which mainly comprises the steps of reacting the higher fatty acid or higher fatty acyl chloride with alpha-hydroxy ketone to obtain an intermediate product, and then reacting the intermediate product with an aromatic aldehyde compound under the catalytic action of an alkali solution to obtain the hydrogen abstraction type photoinitiator based on the higher fatty acid. The preparation method is based on the claisen-Schmidt reaction, the prepared ketene derivative can be used as a free radical hydrogen abstraction type photoinitiator, and the absorption wavelength of the photoinitiator can be adjusted to match light sources of different wave bands for photocuring according to the difference of aromatic rings in the molecular structure of the photoinitiator; in addition, the preparation method is simple and easy to operate.

2. The invention also discloses a hydrogen abstraction type photoinitiator based on the higher fatty acid, which contains a long alkyl chain of the higher fatty acid, so that the polarity of the photoinitiator can be enhanced, and the ketene photoinitiator and a prepolymer in a photocuring formula are endowed with good compatibility; meanwhile, the molecular weight of the photoinitiator can be increased, and the residual photoinitiator after the reaction is finished is prevented from migrating out of the curing film to generate toxicity and odor.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Example 1

A hydrogen abstraction type photoinitiator based on higher fatty acid is prepared, and the specific preparation method is as follows:

1. 28.2g (0.1mol) of oleic acid and 12.7g (0.1mol) of oxalyl chloride are dissolved in N, N-Dimethylformamide (DMF) solvent, after 24 hours of reaction at 140 ℃ to obtain an acid chloride compound (determined by dot plate), 7.4g (0.1mol) of hydroxyacetone is added, 0.635g of triethylamine is added as a catalyst, after 5 hours of reaction at 70 ℃, the pH value of the system is adjusted to be neutral by using triethylamine, after cooling, the dot plate is purified by column chromatography to obtain an intermediate product.

2. Adding 16.6g (0.05mol) of intermediate product and 9.8g (0.1mol) of 2-pyrrole formaldehyde in ethanol solvent, dropwise adding 3-5 drops of 5% by mass NaOH aqueous solution (solution prepared by 0.5g of NaOH and 9.5g of water) to adjust the pH value to 13, reacting for 3 hours at 30 ℃ under the protection of nitrogen, continuing to react for about 3 hours by using an ice bath until light yellow solid is separated out, washing with water, and drying with anhydrous sodium sulfate to obtain hydrogen abstraction type photoinitiators NH-1 and NH-2 based on higher fatty acid, wherein the hydrogen abstraction type photoinitiator has the structure that:

NH-1：

wherein¹H-NMR(CDCl₃) δ -12.52 (-NH), δ -1.56-2.62 (on the long hydrocarbon chain of oleic acid-CH)₂) δ ═ 5.95-7.01 (on the pyrrole ring — CH);

NH-2：

wherein¹H-NMR(CDCl₃) δ -12.52 (-NH), δ -1.02-2.83 (on the long hydrocarbon chain of oleic acid-CH)₂) And delta is 6.95-8.09 (pyrrole ring-CH).

The maximum absorption wavelength of NH-1 is 333nm, the maximum absorption wavelength of NH-2 is 345nm, and the maximum absorption range is 500nm, which indicates that the photoinitiators NH-1 and NH-2 prepared by the method in example 1 have an ultraviolet blue light absorption range, and can be used as an ultraviolet blue light photoinitiator, and in example 1, triethanolamine is used as an auxiliary initiator, the double bond conversion rate of monomer hydroxyethyl acrylate is 70%, and the application prospect in the field of photopolymerization technology is met.

Example 2

A hydrogen abstraction type photoinitiator based on higher fatty acid is prepared, and the specific preparation method is as follows:

1. 28.4g (0.1mol) of octadecanoic acid and 10.2g (0.1mol) of 3-hydroxy-2-pentanone were dissolved in acetonitrile solution, 2mL of concentrated sulfuric acid was added as a catalyst, and after reaction at 70 ℃ for 2 hours, the mixture was cooled to precipitate a solid, which was washed with water and dried with anhydrous sodium sulfate to obtain an intermediate product.

2. Adding the intermediate product and 9.6g (0.1mol) of furfural into an ethanol solvent for dissolving, dropwise adding 3-5 drops of a 5% NaOH aqueous solution (prepared from 0.5g of NaOH and 9.5g of water) with a mass fraction, adjusting the pH value to 13, reacting for 3 hours under the protection of nitrogen at 70 ℃, continuing reacting for 3 hours in an ice bath, separating out a light yellow solid, washing with water, and drying with anhydrous sodium sulfate to obtain a hydrogen abstraction type photoinitiator O-1 based on higher fatty acid, wherein the hydrogen abstraction type photoinitiator has the structure that:

wherein¹H-NMR (CDCl3): delta-1.12-2.51 (on the octadecanoic acid long hydrocarbon chain-CH)₂) δ is 7.65 to 8.29 (furan ring-CH), δ is 7.52, 7.05(-CH ═ CH).

The maximum absorption wavelength of O-1 is 328nm, the maximum absorption range is 500nm, which shows that the photoinitiator O-1 prepared by the method in example 2 has an ultraviolet blue light absorption range and can be used as an ultraviolet blue light photoinitiator, and in example 2, triethanolamine is used as an auxiliary initiator, the double bond conversion rate of monomer hydroxyethyl acrylate is 80%, which accords with the application prospect in the field of photopolymerization technology.

Example 3

A hydrogen abstraction type photoinitiator based on higher fatty acid is prepared, and the specific preparation method is as follows:

1.56 g (0.2mol) of linoleic acid and 11g (0.1mol) of 1.5-hydroxypentanone were dissolved in an acetonitrile solution, concentrated sulfuric acid was added as a catalyst, and the mixture was reacted at 70 ℃ for 2 hours, cooled to precipitate a solid, washed with water, and dried over anhydrous sodium sulfate to obtain an intermediate product.

2. Adding the intermediate product and 22.4g (0.2mol) of thiophenecarboxaldehyde into an ethanol solvent, dropwise adding 3-5 drops of a 5% NaOH aqueous solution (prepared from 0.5g of NaOH and 9.5g of water) at a mass fraction, adjusting the pH value to 13, reacting for 3 hours under the protection of nitrogen at 70 ℃, continuing reacting for 3 hours by using an ice bath, precipitating a light yellow solid, washing the product with water, and drying anhydrous sodium sulfate to obtain a higher fatty acid-based hydrogen abstraction type photoinitiator S-1, wherein the hydrogen abstraction type photoinitiator has the structure:

wherein¹H-NMR(CDCl₃) Delta. is 0.98-2.87 (on the long hydrocarbon chain of linoleic acid-CH)₂) And delta is 7.64-8.32 (thiophene ring-CH).

The maximum absorption wavelength of S-1 is 383nm, the maximum absorption range is 550nm, which shows that the photoinitiator O-1 prepared by the method in the embodiment 3 has an ultraviolet blue light absorption range and can be used as an ultraviolet blue light photoinitiator, triethanolamine is used as an auxiliary initiator, the double bond conversion rate of monomer hydroxyethyl acrylate is 75%, and the application prospect in the field of photopolymerization technology is met.

Example 4

A hydrogen abstraction type photoinitiator based on higher fatty acid is prepared, and the specific preparation method is as follows:

1. 28g (0.1mol) of linoleic acid and 11.4g (0.1mol) of 2-hydroxycyclohexanone were dissolved in an acetonitrile solution, concentrated sulfuric acid was added as a catalyst, the reaction was carried out at 75 ℃ for 2 hours, a solid was precipitated by cooling, washed with water, and dried over anhydrous sodium sulfate to obtain an intermediate product.

2. Adding the intermediate product and 22.4g (0.1mol) of N-methyl-2-pyrrole formaldehyde into an ethanol solvent, dropwise adding 3-5 drops of a 5% NaOH aqueous solution (prepared from 0.5g of NaOH and 9.5g of water) in mass fraction, adjusting the pH value to 13, reacting for 3 hours under the protection of nitrogen at 75 ℃, continuing reacting for 3 hours in an ice bath, precipitating a light yellow solid, washing the product with water, and drying anhydrous sodium sulfate to obtain a hydrogen abstraction type photoinitiator NCH-1 based on higher fatty acid, wherein the hydrogen abstraction type photoinitiator has the structure that:

wherein¹H-NMR(CDCl₃) δ being 1.02-2.99 (on the long hydrocarbon chain of linoleic acid-CH)₂) δ ═ 3.98 (N-methyl-2-pyrrolecarboxaldehyde-CH₃) And delta is 6.70-9.25 (pyrrole ring-CH).

Wherein the maximum absorption wavelength of NCH-1 is 355nm, and the maximum absorption range is 500nm, which indicates that the photoinitiator NCH-1 prepared by the method in example 4 has an ultraviolet blue light absorption range and can be used as an ultraviolet blue light photoinitiator. The conversion rate of double bonds of monomer hydroxyethyl acrylate is 65 percent without adding auxiliary initiator; in example 4, triethanolamine is used as an initiator aid, and the conversion rate of double bonds of monomer hydroxyethyl acrylate is 88%, which meets the application prospect in the field of photopolymerization technology.

In summary, the invention discloses a preparation method of a higher fatty acid-based hydrogen abstraction photoinitiator, which mainly comprises the steps of reacting a higher fatty acid or higher fatty acyl chloride to obtain an intermediate product, and then reacting the intermediate product with an aromatic aldehyde compound under the catalytic action of an alkali solution to obtain the higher fatty acid-based hydrogen abstraction photoinitiator. The preparation method is based on the claisen-Schmidt reaction, the prepared ketene derivative can be used as a free radical hydrogen abstraction type photoinitiator, and the absorption wavelength of the photoinitiator can be adjusted to match light sources of different wave bands for photocuring according to the difference of aromatic rings in the molecular structure of the photoinitiator; in addition, the preparation method is simple and easy to operate. The invention also discloses a hydrogen abstraction type photoinitiator based on the higher fatty acid, which contains a long alkyl chain of the higher fatty acid, so that the polarity of the photoinitiator can be enhanced, and the ketene photoinitiator and a prepolymer in a photocuring formula are endowed with good compatibility; meanwhile, the molecular weight of the photoinitiator can be increased, and the residual photoinitiator after the reaction is finished is prevented from migrating out of the curing film to generate toxicity and odor.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all that should be covered by the claims of the present invention.