CN110305086B

CN110305086B - Benzophenone derivative containing five-membered heterocycle and preparation method and application thereof

Info

Publication number: CN110305086B
Application number: CN201910603295.4A
Authority: CN
Inventors: 张变香; 王晨
Original assignee: Shanxi University
Current assignee: Shanxi University
Priority date: 2019-07-05
Filing date: 2019-07-05
Publication date: 2022-03-18
Anticipated expiration: 2039-07-05
Also published as: CN110305086A

Abstract

The invention provides a benzophenone derivative containing five-membered heterocycle and a preparation method and application thereof. Preparation of derivatives: 2, 4-dihydroxy benzophenone is used as a raw material to react with heterocyclic acyl chloride to synthesize two benzophenone derivatives I and II containing five-membered heterocycles. The preparation method has the advantages of simple operation, mild reaction conditions, high total yield and the like. The derivative I can effectively absorb ultraviolet light of 250-360 nm, can enhance the light stability of ultraviolet curing coatings and coatings when used as an ultraviolet light absorbent, and has the characteristics of good compatibility with resin or monomers, no odor and the like; it is also beneficial to the storage of the ultraviolet curing coating. The derivative II introduces O, S heteroatom rich in electrons on the basis of benzophenone structure skeleton, so that its ultraviolet absorption wavelength is red-shifted, and the utilization rate of light source is increased. The two derivatives synthesized by the invention can be respectively used as ultraviolet light absorbers and ultraviolet light initiators to be applied to the fields of photocuring compositions such as coatings, printing ink, adhesives and the like.

Description

Benzophenone derivative containing five-membered heterocycle and preparation method and application thereof

Technical Field

The invention relates to a benzophenone derivative, in particular to a benzophenone derivative containing five-membered heterocycle and a preparation method and application thereof.

Background

When the high polymer material is used outdoors, the high polymer material is easy to degrade under the irradiation of sunlight, and the phenomena of gloss reduction, embrittlement, cracking and the like occur, so that an ultraviolet absorbent needs to be added to resist the ultraviolet light deterioration reaction, enhance the weather resistance and provide more complete protection effect for the high polymer material. The ultraviolet absorbent is mainly composed of a structure containing a pi-conjugated system in a molecule, absorbs ultraviolet rays by utilizing a specific structure of the ultraviolet absorbent and releases or consumes energy in the form of heat energy or harmless low-energy radiation, and the commonly used ultraviolet absorbent comprises three types of benzophenone, benzotriazole and triazine. Benzophenone is a widely used material at present, is widely used in the industries of plastics, printing ink, paint, cosmetics and the like due to good compatibility with other materials, but has the defects of small relative molecular mass, easy volatilization in the material processing process, small molecular migration, easy yellowing and the like in products, so that the material performance cannot achieve the expected effect. Therefore, in practical application, people put forward new requirements on the structure and performance of the ultraviolet absorbent, expect stable and efficient products, and realize advantage complementation for filling the gap of the existing materials.

In addition, the photocuring technology has the advantages of energy conservation, environmental protection, high efficiency, high speed and the like, and is widely applied to the traditional fields of coatings, printing ink, adhesives and the like and high and new technology products such as 3D printing and the like. The photoinitiator in the photocuring system is a key component, and the benzophenone is a common photoinitiator which is low in price, simple to synthesize and easy to store, and is widely applied to the ultraviolet curing coating. However, the ultraviolet absorption intensity of benzophenone is not strong, and the absorption range is narrow, so that the photoinitiation activity is not ideal. With the rapid development of the industry, on the basis of the molecular structure of the benzophenone, through reasonable molecular design and the relation research between the molecular structure and the performance thereof, the photoinitiator with high efficiency, low toxicity and low mobility is researched and developed, and the photoinitiator has wide application prospect.

Disclosure of Invention

The invention aims to provide a benzophenone derivative containing a five-membered heterocycle and a preparation method thereof aiming at the problems in the prior art. The invention has the advantages of simple preparation operation, mild reaction conditions, high total yield and the like, and the synthesized benzophenone derivative containing the five-membered heterocycle can be applied as an ultraviolet light absorber or an ultraviolet light initiator.

The benzophenone derivative containing the five-membered heterocycle provided by the invention has a structural general formula of I or II:

wherein X is O or S.

The method specifically comprises the following steps:

the reaction formula is as follows:

wherein X is O or S.

The preparation method comprises the following steps:

1) adding 2, 4-dihydroxy benzophenone into a container, dissolving the benzophenone by using an organic solvent, slowly adding triethylamine, stirring uniformly under the ice-water bath condition, dropwise adding 2-furoyl chloride or 2-thiophenecarbonyl chloride, and stirring for reacting for 6-24 hours;

2) after the reaction is finished, adding water into the reaction solution, extracting with ethyl acetate, collecting an organic phase, washing with water, drying, and removing the organic solvent by rotary evaporation; separating and purifying by using a chromatographic silica gel column to respectively obtain the benzophenone derivative I containing the five-membered heterocycle or the benzophenone derivative II containing the five-membered heterocycle.

The molar ratio of the 2, 4-dihydroxy benzophenone, the triethylamine and the 2-furoyl chloride or 2-thiophenecarbonyl chloride in the step 1) is 1: 1.4-2: 1.2-2.5, preferably 1:1.5: 2.

The organic solvent in the step 1) is tetrahydrofuran or dichloromethane, preferably dichloromethane;

the reaction time described in step 1) is preferably 12 hours.

The eluent of the chromatographic silica gel column in the step 2) is petroleum ether and ethyl acetate in a volume ratio of 1-10: 1, preferably 3-7: 1.

The invention takes 2, 4-dihydroxy benzophenone as raw material to react with heterocyclic acyl chloride, and four benzophenone derivatives containing five-membered heterocycle are rapidly synthesized. The synthesis method has the advantages of simple operation, mild reaction conditions, high total yield and the like. The derivatives 1 and 3 can effectively absorb ultraviolet light of 250-360 nm, can enhance the light stability of ultraviolet curing coatings and coatings, and have the characteristics of good compatibility with resin or monomers, no odor and the like; and is also beneficial to the preparation and storage of the ultraviolet curing coating. Meanwhile, O, S heteroatom rich in electrons is introduced into the derivatives 2 and 4 on the basis of the structural skeleton of benzophenone, so that the ultraviolet absorption wavelength of the compound is red-shifted, and the utilization rate of a light source is increased. The benzophenone derivative containing the five-membered heterocycle synthesized by the invention can be respectively used as an ultraviolet light absorber and an ultraviolet light initiator to be applied to the fields of photocuring compositions such as paint, printing ink, adhesive and the like.

Drawings

FIG. 12 is a UV absorption spectrum of hydroxy-4-furoyloxybenzophenone (derivative 1)

FIG. 22, UV absorption spectrum of 4-difurancarbonyloxy benzophenone (derivative 2)

FIG. 32 ultraviolet absorption spectrum of hydroxy-4-thiophenecarboxoyloxybenzophenone (derivative 3)

FIG. 42 UV absorption spectrum of 4-bisthiophene formyloxy benzophenone (derivative 4)

Detailed Description

Example 1

0.214g (1mmol) of 2, 4-dihydroxybenzophenone and 0.150g (1.5mmol) of triethylamine were added to the vessel, and the mixture was dissolved in 3ml of dichloromethane, and 0.261g (2mmol) of 2-furoyl chloride was slowly added thereto under ice-water bath conditions, followed by stirring and reacting for 12 hours. After the reaction is finished, adding water into the reaction solution, extracting with ethyl acetate, collecting an organic phase, washing with water, drying with anhydrous sodium sulfate, and removing the organic solvent by rotary evaporation; and separating by column chromatography with petroleum ether and ethyl acetate (volume ratio 3:1) as eluent to obtain 2-hydroxy-4-furoyloxy benzophenone (derivative 1) and 2, 4-difuranoyloxy benzophenone (derivative 2).

Derivative 1: white solid, yield 46%, m.p.93-96 ℃.¹H NMR(600MHz,CDCl₃)δ12.47–12.22(m,1H),7.69(dd,J＝25.5,11.6Hz,4H),7.65–7.59(m,1H),7.54(dd,J＝18.7,11.3Hz,

2H),7.44(s,1H),7.00(d,J＝18.8Hz,1H),6.81(d,J＝8.7Hz,1H),6.66(d,J＝20.2Hz,1H).¹³C NMR(151MHz,CDCl₃)δ200.82,164.83,156.10,155.91,147.66,143.46,137.75,134.98,132.11,129.11,128.49,120.24,117.25,112.61,112.42,111.25.

Derivative 2: colorless transparent liquid, the yield is 40 percent,¹H NMR(600MHz,CDCl₃)δ7.80(dd,J＝17.0,8.0Hz,2H),7.76–7.65(m,2H),7.61–7.49(m,2H),7.48–7.40(m,3H),7.39–7.30(m,2H),6.96(d,J＝19.2Hz,1H),6.69–6.60(m,1H),6.50–6.42(m,1H).¹³C NMR(151MHz,CDCl₃)δ193.81,155.99,155.81,152.71,148.96,147.74,147.51,143.33,142.99,137.46,133.06,131.57,129.80,129.36,128.40,120.30,119.89,119.31,116.94,112.44,112.11.

example 2

0.214g (1mmol) of 2, 4-dihydroxybenzophenone and 0.150g (1.5mmol) of triethylamine were added to the vessel, and the mixture was dissolved in 3ml of dichloromethane, and 0.292g (2mmol) of 2-thiophenecarbonyl chloride was slowly added thereto under ice-water bath conditions, followed by stirring and reacting for 12 hours. After the reaction is finished, adding water into the reaction solution, extracting with ethyl acetate, collecting an organic phase, washing with water, drying with anhydrous sodium sulfate, and removing the organic solvent by rotary evaporation; and separating by column chromatography with petroleum ether as eluent to obtain 2-hydroxy-4-thiophene formyloxy benzophenone (derivative 3) and 2, 4-bithiophene formyloxy benzophenone (derivative 4).

Derivative 3: white solid, 36% yield, m.p.83-85 ℃.¹H NMR(600MHz,CDCl₃)δ12.43–12.16(m,1H),8.02(s,1H),7.76–7.66(m,4H),7.66–7.59(m,1H),7.54(dd,J＝15.6,8.3Hz,2H),7.25–7.19(m,1H),6.98(d,J＝16.8Hz,1H),6.81(t,J＝12.8Hz,1H).¹³C NMR(151MHz,CDCl₃)δ200.82,164.83,159.64,156.56,137.78,135.27,134.94,134.21,132.18,132.10,129.13,128.48,128.24,117.18,112.69,111.29.

Derivative 4: colorless transparent liquid, yield: 48%.¹H NMR(600MHz,CDCl₃)δ8.02(d,J＝17.1Hz,1H),7.82(t,J＝9.0Hz,2H),7.71(dd,J＝20.2,6.5Hz,2H),7.67–7.47(m,3H),7.47–7.30(m,4H),7.21(d,J＝14.2Hz,1H),7.09–7.00(m,1H).¹³C NMR(151MHz,CDCl₃)δ193.93,159.77,159.59,153.04,149.22,137.53,135.29,135.00,134.25,133.99,133.05,132.09,131.68,131.49,129.79,129.35,128.43,128.26,127.86,119.28,117.03.

And simultaneously, the ultraviolet absorption of the derivative 1, the derivative 2, the derivative 3 and the derivative 4 is determined and analyzed, and the result shows that the compound has better ultraviolet absorption performance compared with benzophenone, can effectively absorb ultraviolet light of 250-360 nm and 250-300 nm, and the ultraviolet spectrum is shown in figures 1-4.

The following examples are provided to specifically illustrate the application of benzophenone derivatives 1 and 3 containing five-membered heterocyclic ring as uv absorber in uv curable coating, but not limited to the use of the following examples.

Example 3: evaluation of Properties of derivative 1 for ultraviolet light absorber

The experimental formula is as follows:

the working conditions are as follows:

adding 50g of epoxy acrylic carboxylic acid resin, 44g of 1, 6-hexanediol diacrylate, 3g of photoinitiator (1173) and 2g of triethanolamine and 1g of 2-hydroxy-4-furancarbonyloxy benzophenone into a glass container with a stirrer, stirring to uniformly disperse and transparent, and standing for 5-10 minutes to obtain the transparent free radical photocuring coating. Dividing the coating into three parts, and putting one part into a transparent glass bottle and covering for daily indoor storage; one part of the mixture is put into a transparent glass bottle and covered in a room to be stored in a dark place; one portion was coated on a glass plate with a squeegee to a film thickness of 75 μm and then cured by an ultraviolet curing apparatus at a speed of 5 meters per minute (light irradiation time of about 5 seconds).

Example 4: evaluation of Properties of derivative 3 for ultraviolet absorber

The experimental formula is as follows:

working conditions were the same as in example 2

Comparative example 1 (No additive ultraviolet absorber)

The experimental formula is as follows:

working conditions were the same as in example 2

Comparative example 2 (without addition of photoinitiator)

The experimental formula is as follows:

working conditions were the same as in example 2

Comparative example 3 (without addition of photoinitiator)

The experimental formula is as follows:

working conditions were the same as in example 2

Comparative example 4 (addition of commercially available UV absorber UV-0)

The experimental formula is as follows:

working conditions were the same as in example 2

TABLE 1 evaluation of storage results after formulation of UV-curable coatings

Experiment of	30min	2h	6h (avoid light)	30h	72h
						Example 3	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Slightly solidified layer
Example 4	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent
						Comparative example 1	With a solidified layer	Complete curing	Complete curing	Complete curing	Complete curing
Comparative example 2	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent
						Comparative example 3	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent
Comparative example 4	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	Is uniform and transparent	With a solidified layer

As can be seen from table 1, the preparation of the uv curable coating is usually carried out under the condition of keeping out of the sun, and the uv curable coating is affected by the uv in the sunlight, and the storage time cannot be long. Compared with comparative example 1, when the inventive derivatives 1 and 3 were added separately as uv absorbers in the preparation of the coating, no more severe conditions of protection from light were required. When only the ultraviolet absorber UV-0 was added to the formulation of comparative example 4, the cured layer was more after 72 hours of storage, whereas example 3 had a slightly cured layer and example 4 had no cured layer. The results show that the derivatives 1 and 3 can effectively absorb ultraviolet light, the effect is better than that of the ultraviolet absorbent UV-0, and the effect of the benzophenone derivative 3 is optimal.

The cured coatings of the compositions of examples 3, 4 and comparative examples 1 to 4 described above were subjected to a performance test:

a: surface dry time test: it refers to dry method or cotton ball method.

b: hardness test pencil hardness method test according to GB/T6739-1996. And observing the scratch marks of the paint film by using a film coating pencil scratch hardness instrument, and taking the pencil without the scratch as the pencil hardness of the coating film.

c: and (3) testing the adhesive force: the cross-cut method (see GB 9286-88). And judging whether the adhesive force of the coating is good or not by a grid-scribing experimental method. The grade can be 0-5, 6 grades, preferably 0 grade, the film surface does not fall off any small grid, 5 grades are extremely poor, and the film surface is seriously peeled off.

TABLE 2 evaluation results of cured coating Properties

Experiment of

Example 3

Example 4

Comparative example 1

Comparative example 2

Comparative example 3

Comparative example 4

Appearance of the product

Smooth and transparent

Not cured

With a pinhole

Hardness of

5H

3H

-

4H

Adhesion force

2

1

2

-

2

As can be seen from Table 2, when the photoinitiator was not added to the UV-curable coating, and only the derivatives 1 or 3 were added, the coating was not cured to form a film (comparative examples 2 and 3); indicating that derivatives 1 and 3 do not participate in the curing film-forming reaction; on the other hand, on the basis of the formula of the conventional ultraviolet curing coating, when the derivative 1 is added, the hardness of a curing film is improved; when the derivative 3 is added to the coating, the hardness and adhesion of the cured film are improved. The cured films obtained in examples 2 and 3 were hard to wipe, smooth and uniform in surface, and free from pungent odor.

Therefore, the derivatives 1 and 3 of the invention have simple preparation and easily obtained raw materials; the ultraviolet light absorbing material can effectively absorb ultraviolet light of 250-360 nm, has strong absorption intensity, and has the characteristics of good compatibility with resin and monomers, no odor and the like. Hardly participates in the curing of a free radical system in the curing process, enhances the light stability of the coating and the cured coating, is suitable for being applied to curing compositions such as coating, printing ink, viscose and the like, is beneficial to the storage of ultraviolet curing coating, and is an ultraviolet absorber with development prospect.

The following examples are comparisons of the curing performance of derivatives 2 and 4 of the present invention as free radical photoinitiators with the curing performance of a commercially available free radical photoinitiator 1173: the oligomer used in the method is modified epoxy acrylate (produced by chemical plant of Chin , Miyama, UV1005-65) and the monomer is 1, 6-hexanediol diacrylate (produced by chemical plant of Chin , Miyama, HDDA).

Example 5: evaluation of applicational Properties of derivative 2

The experimental formula is as follows:

working conditions

Under the dark condition, 20.03 g of 2, 4-difuranyl formyloxy benzophenone, 0.5g of modified epoxy acrylate (UV1005-65), 0.45g of 1, 6-hexanediol diacrylate (HDDA) and 0.02g of triethanolamine are added into a glass container, and the mixture is uniformly stirred to form transparent coating liquid. The mixture was coated on a glass plate with a coater to give a film having a thickness of 75 μm, and cured by irradiation with a medium-pressure mercury lamp at a mercury lamp power of 400W.

Example 6: evaluation of applicational Properties of derivative 4

The experimental formula is as follows:

working conditions were the same as in example 4

Comparative example 5: evaluation of application Properties of photoinitiator 1173

The experimental formula is as follows:

working conditions were the same as in example 5

The coating films of the compositions of examples 5, 6 and 5 were subjected to performance tests:

a, testing the dry time: it refers to dry method or cotton ball method.

b hardness test pencil hardness method test according to GB/T6739-1996. And observing the scratch marks of the paint film by using a film coating pencil scratch hardness instrument, and taking the pencil without the scratch as the pencil hardness of the coating film.

c, testing adhesive force: the cross-cut method (see GB 9286-88). And judging whether the adhesive force of the coating is good or not by a grid-scribing experimental method. The grade can be 0-5, 6 grades, preferably 0 grade, the film surface does not fall off any small grid, 5 grades are extremely poor, and the film surface is seriously peeled off.

The evaluation results are shown in Table 3.

TABLE 3 comparison of the performance of derivatives 2,4 and 1173 in use

From the test results in the table above, it can be seen that: the curing speed of the derivative 2 is relatively slow, but the hardness and the adhesive force of a cured film are superior to those of a commercially available free radical type photoinitiator 1173; the curing speed, the hardness and the adhesive force of the derivative 4 are superior to those of a commercially available free radical photoinitiator 1173, and the two can be used as ultraviolet initiators to be applied to the fields of photocuring compositions such as coatings, printing ink, adhesives and the like.

Claims

1. A benzophenone derivative containing a five-membered heterocycle is characterized in that the structural formula is I or II:

in the structural formula, X is O or S.

2. A preparation method of benzophenone derivatives containing five-membered heterocyclic rings is characterized in that the reaction formula is as follows:

wherein X is O or S.

3. The process for preparing benzophenone derivatives containing five-membered heterocyclic ring according to claim 1, comprising the steps of:

4. The method for preparing the benzophenone derivative containing the five-membered heterocycle according to claim 3, wherein the molar ratio of the 2, 4-dihydroxybenzophenone, the triethylamine and the 2-furoyl chloride or the 2-thiophenecarbonyl chloride in the step 1) is 1:1.4 to 2:1.2 to 2.5.

5. The method according to claim 3, wherein the organic solvent used in step 1) is tetrahydrofuran or dichloromethane.

6. The process for producing a benzophenone derivative containing a five-membered heterocyclic ring according to claim 3, wherein the reaction time in the step 1) is 12 hours.

7. The preparation method of the benzophenone derivative containing five-membered heterocycle according to claim 3, wherein the eluent of the chromatographic silica gel column in the step 2) is petroleum ether and ethyl acetate in a volume ratio of 1-10: 1.

8. Use of the benzophenone derivative I containing a five-membered heterocycle according to claim 1 as an ultraviolet absorber.

9. Use of the benzophenone derivative II containing five-membered heterocycle according to claim 1 as uv-photoinitiator.