CN111574425A - Novel benzoyl formic acid methyl ester photoinitiator and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of organic synthesis, in particular to a novel methyl benzoylformate photoinitiator and a preparation method thereof. The emission wavelength range of LED light sources currently used in the market is above 365nm, while the maximum absorption wavelength of traditional photoinitiator MBF is 255nm, which does not match the emission wavelength of LED light source. In order to make the maximum absorption wavelength of MBF photoinitiator The wavelength matches the main emission wavelength range of the LED light source, and the present invention provides a novel methyl benzoate photoinitiator, which is composed of a carbonyl-functionalized methyl benzoate derivative containing bisαH and a ketone. The compound is obtained by condensation reaction, and its maximum absorption wavelength can reach more than 365nm, which matches the LED light source used in the market and has a good commercial application prospect.

Description

A novel methyl benzoylformate photoinitiator and preparation method thereof

technical field

The invention relates to the technical field of organic synthesis, in particular to a novel methyl benzoylformate photoinitiator and a preparation method thereof.

Background technique

Photoinitiator MBF, also known as methyl benzoyl formate. Methyl benzoylformate is a colorless or light yellow liquid, soluble in organic solvents such as toluene, ethanol, and ether. It has many advantages such as high temperature, good thermal stability and low odor, and plays an important role in the photopolymerization system.

Mercury lamps will be banned as China signs the Minamata Convention. LED light source is a new type of low-power light source. Compared with mercury lamps, it has many advantages, such as high efficiency, no ozone generation, no mercury pollution, long life, etc. In recent years, it has been widely used in the field of photopolymerization. . However, due to packaging technology and other reasons, LED light sources cannot continuously and stably emit short-wavelength ultraviolet light. The main emission wavelengths are concentrated in 365nm-400nm, while the main absorption wavelengths of traditional photoinitiator MBF are 255nm and 325nm. If an LED light source is used to provide the energy of the photopolymerization reaction, and MBF is used as the photoinitiator of the photopolymerization reaction, the double bond conversion rate of the polymerized monomer in the photopolymerization reaction will be relatively small. Therefore, it is of great commercial value to develop long-wavelength photoinitiators that match the emission wavelength of LED light sources.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the technical problem to be solved by the present invention is: how to improve the maximum absorption wavelength of the traditional photoinitiator MBF, so that it can be adapted to the main emission wavelength of the LED light source, and improve the double bond in the photopolymerization reaction. Conversion rate.

The technical scheme adopted by the present invention to solve its technical problems is:

The present invention provides a novel methyl benzoylformate photoinitiator, which has the following general chemical structure:

In the general formula of the above chemical structure, n=1-2, in the general formula I: 4R ₂ represents a substituent on 4 arbitrary vacancies on the benzene ring; R ₁ and R ₂ are hydrogen atoms, alkyl groups, alkenyl groups, alkoxy groups one of alkynyl, alkynyl, hydroxyl, nitro, halogen, sulfonic acid, and alkyl, alkenyl, alkoxy, alkynyl substituted by hydroxyl, halogen, nitro, sulfonic acid, cyano, amino ; R ₃ is one of an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and a heterocyclic aromatic group.

Specifically, described a kind of novel methyl benzoylformate photoinitiator is characterized in that, has following chemical formula:

Specifically, a preparation method of a novel methyl benzoate photoinitiator is prepared according to the following steps:

(1) First prepare a carbonyl-functionalized methyl benzoylformate derivative containing double αH;

(2) Condensation reaction occurs between the carbonyl-functionalized methyl benzoylformate derivative containing double αH and the aldehyde compound, after the reaction is completed, after the obtained solid product is purified, a novel methyl benzoylformate type light is obtained. initiator.

Specifically, the carbonyl-functionalized methyl benzoylformate derivative containing double αH has the following chemical formula:

Specifically, the aldehyde compounds are 1-methyl-2-pyrrolecarbaldehyde, terephthalaldehyde, furfural, p-tolualdehyde, 2,5-diformylfuran, 1-methyl-1H-pyrrole-2, 5-dicarbaldehyde or benzaldehyde.

Specifically, in the condensation reaction, the molar ratio of the carbonyl-functionalized methyl benzoylformate derivative containing double αH to the aldehyde compound is 1-2:1.

Specifically, the temperature of the condensation reaction is 0-80° C., the reaction time is 0.05-6 h, and pH=8-13.

Specifically, the solvent for the condensation reaction is methanol, ethanol, isopropanol, tert-butanol, tetrahydrofuran, dimethylformamide or dimethylsulfoxide.

Specifically, the catalyst of the condensation reaction is sodium hydroxide, potassium hydroxide, sodium tert-butoxide, potassium tert-butoxide, sodium bicarbonate, diisopropylamine, pyridine, lithium diisopropylamide, triethanolamine, methyl Diethanolamine or lithium hexamethyldisilazide.

The beneficial effects of the present invention are:

(1) The maximum absorption wavelength of the novel methyl benzoylformate photoinitiator prepared by the present invention can reach more than 356 nm, which matches the emission wavelength of LED light sources commonly used in the field of photopolymerization, and has more excellent performance and greater market potential. powerful.

(2) The method for preparing the novel methyl benzoylformate photoinitiator of the present invention is simple, and the product can be obtained only through one-step condensation reaction, the preparation cost is low, and industrial production is easy.

Description of drawings

Figure 1: UV absorption spectra of conventional commercial MBF photoinitiators.

Figure 2: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 1.

Figure 3: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 2.

Figure 4: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 3.

Figure 5: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 4.

Figure 6: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 5.

Figure 7: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 6.

Figure 8: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 7.

Figure 9: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 8.

Figure 10: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 9.

Figure 11: UV absorption spectrum of the long-wavelength photoinitiator prepared in Example 10.

Detailed ways

The present invention will now be described in further detail with reference to the accompanying drawings.

Example 1

(1) Preparation Example of 2-(4-acetylphenyl)-2-oxoacetic acid methyl ester:

2mol 4-methylacetophenone and 4mol selenium dioxide were dissolved in 1000mL pyridine, and reacted under nitrogen at 1200°C for 18h. After the reaction, the reaction mixture was filtered and evaporated to remove the organic solvent, and then 200ml of 2mol/L hydroxide was added. Sodium solution, then add 200ml of ethyl acetate, then dropwise add 100ml of concentrated hydrochloric acid with a mass concentration of 65%, and the organic phase is directly liquid-separated and rotary-evaporated to obtain pale yellow oily 2-oxo-2-(p-tolyl)acetic acid;

(2) 0.5 mol of 2-oxo-2-(p-tolyl) acetic acid and 1.7 mol of potassium carbonate were dissolved in 200 mL of DMSO, 57 mL of dimethyl sulfate was added dropwise, and the reaction mixture was stirred at room temperature for 0.5 h. Mixed with 200ml of ether, after liquid separation, the ether phase was collected, washed three times with 50ml of 1mol/L potassium carbonate solution, washed once with 100ml of saturated brine, dried with anhydrous magnesium sulfate, filtered, and the filtrate was rotary evaporated to obtain Methyl 2-oxo-2-(p-tolyl)acetate;

(3) 0.2mol 2-oxygen-2-(p-tolyl) methyl acetate was dissolved in 100ml ethanol, 3.4g manganese dioxide was added, and 20ml was slowly added dropwise with a mass concentration of 74% H ₂ SO ₄ aqueous solution After 0.5h of reaction, 25ml of saturated brine and 25ml of ethyl acetate were added for extraction to obtain 2-(4-formylphenyl)-2-oxyacetic acid methyl ester;

(4) Dissolve 0.1 mol of methyl 2-(4-formylphenyl)-2-oxyacetate in 200 ml of ether, add 0.12 mol of 0.15 mol of CH ₃ MgBr, react for 1 h, add 100 ml of saturated solution to the reaction solution In the mixed solution of ammonium chloride and dichloromethane, the dichloromethane phase was collected and rotary-evaporated to obtain 2-(4-acetylphenyl)-2-oxoacetic acid methyl ester;

(5) 0.1 mol of methyl 2-(4-acetylphenyl)-2-oxoacetate and 0.1 mol of 1-methyl-2-pyrrole carboxaldehyde were added to 50 mL of ethanol to dissolve, and the mass fraction was 1wt% NaOH The aqueous solution was used as a catalyst, and the pH was adjusted to 8. After 5 hours of reaction at 80 °C, the reaction system continuously precipitated solids during cooling. The solids were filtered, washed, and dried in vacuum to finally obtain a new type of methyl benzoylformate photoinitiator. The reaction equation as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 3.61(s, 3H), 3.91 (s,3H), 6.07(m,1H), 6.64(m,1H), 7.15(m,1H), 7.59(d,1H), 7.90(d,1H), 8.04(m,4H); MS( m/z): 297(M+1) ⁺ .

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 359 nm (see Figure 2 in the description), and under the irradiation of an LED point light source with a wavelength of 365 nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 79%.

Example 2

Add 0.09 mol of methyl 2-(4-acetylphenyl)-2-oxoacetate and 0.05 mol of terephthalaldehyde into 40 mL of ethanol to dissolve, and use a 1.5 wt% NaOH aqueous solution as a catalyst to adjust pH= 9. After 4 hours of reaction at 70°C, the heating was stopped and cooled at room temperature. It was found that a solid was precipitated. The solid was filtered, washed with a small amount of methanol, recrystallized, and dried in vacuo to finally obtain a new type of methyl benzoylformate photoinitiator. The reaction The equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ^1H -NMR and MS, 1H-NMR (d-DMSO, 400MHz)δ(ppm): 3.61(s, 6H), 7.03( s, 2H), 7.29(m, 4H), 7.60(d, 2H), 8.04(m, 8H); MS(m/z): 510(M+1)+;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 367nm (see Figure 3 in the description), and under the irradiation of an LED point light source with a wavelength of 365nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA was 80% within 250s.

Example 3

(1) Preparation example of methyl 2-(4-propionylphenyl)-2-oxoacetate:

2mol 4-methylacetophenone and 4mol selenium dioxide were dissolved in 1000mL pyridine, reacted under 1200C nitrogen for 18h, after the reaction finished, the reaction mixture was filtered and evaporated to remove the organic solvent, then 200ml 2mol/L sodium hydroxide was added solution, then add 200ml of ethyl acetate, then dropwise add 100ml of concentrated hydrochloric acid with a mass concentration of 65%, and directly liquid-separate the organic phase by rotary evaporation to obtain pale yellow oily 2-oxo-2-(p-tolyl)acetic acid;

(2) 0.5 mol of 2-oxo-2-(p-tolyl) acetic acid and 1.7 mol of potassium carbonate were dissolved in 200 mL of DMSO, 57 mL of dimethyl sulfate was added dropwise, and the reaction mixture was stirred at room temperature for 0.5 h. Mixed with 200ml of ether, separated, collected the ether phase, washed three times with 50ml of 1mol/L potassium carbonate solution, washed once with 100ml of saturated brine, dried with anhydrous magnesium sulfate, filtered, and rotary-evaporated the filtrate to obtain 2- Methyl oxy-2-(p-tolyl)acetate;

(3) 0.2mol 2-oxygen-2-(p-tolyl) methyl acetate was dissolved in 100ml ethanol, 3.4g manganese dioxide was added, and 20ml was slowly added dropwise with a mass concentration of 74% H ₂ SO ₄ aqueous solution , after 0.5h of reaction, add a small amount of brine and ethyl acetate for extraction to obtain 2-(4-formylphenyl)-2-oxyacetic acid methyl ester;

(4) Dissolve 0.1 mol of methyl 2-(4-formylphenyl)-2-oxoacetate in 200 ml of ether, add 0.15 mol of CH ₃ CH ₂ MgBr, react for 1 h, add the reaction solution to 100 ml In the mixed solution of saturated ammonium chloride and dichloromethane, the dichloromethane phase was collected, and after rotary evaporation, 2-(4-acetylphenyl)-2-oxoacetic acid methyl ester was obtained;

(5) 0.11mol of methyl 2-(4-propionylphenyl)-2-oxoacetate and 0.1mol of furfural formaldehyde were added into 45mL of ethanol to dissolve, and the mass fraction of 1wt% KOH aqueous solution was used as a catalyst to adjust pH= After reacting at 10 and 60°C for 3 hours, the temperature was lowered slowly to separate out a solid, which was filtered, washed with a small amount of ethanol, and dried in vacuum to finally obtain a novel methyl benzoylformate photoinitiator. The reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 2.34(s, 3H), 3.61 (s, 3H), 6.85 (m, 1H), 7.63 (m, 2H), 8.04 (m, 4H), 8.16 (m, 1H);

MS (m/z): 298 (M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 366 nm (see Figure 4 in the description), and under the irradiation of an LED point light source with a wavelength of 365 nm, the initiator concentration is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 81%.

Example 4

0.19mol of methyl 2-oxo-2-(4-propionylphenyl)acetate and 0.1mol of 1-methyl-1H-pyrrole-2,5-dicarbaldehyde were added to 60mL of methanol to dissolve, and the mass fraction was 1.5 wt% potassium tert-butoxide ethanol solution was used as a catalyst, adjusted to pH=11, reacted at 25°C for 2 h, and extracted the reaction product with saturated brine with dichloromethane for several times, and the organic extract was rotary evaporated with a rotary evaporator to obtain a solid product, The solid product is washed with ethanol and dried in vacuum to finally obtain a novel methyl benzoylformate photoinitiator, and the reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 2.34(s, 6H), 3.58 (s, 3H), 3.61(s, 3H), 6.49(s, 2H), 7.62(s, 2H), 7.70(m, 2H), 8.13(m, 6H); MS(m/z): 541( M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 365nm (see Figure 5 in the description), and under the irradiation of an LED point light source with a wavelength of 365nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 83%.

Example 5

0.17mol of methyl 2-oxo-2-(4-propionylphenyl)acetate and 0.15mol of p-tolualdehyde were added to 60mL of methanol to dissolve, and 2wt% potassium tert-butoxide ethanol solution was used as a catalyst to adjust pH=about 11 , After reacting at 15°C for 1 h, the reaction liquid was extracted several times with a small amount of 1:1 saturated brine of dichloromethane, and the solid product was obtained by rotary evaporation. The solid product was washed with methanol and vacuum dried to finally obtain a new type of methyl benzoylformate Ester photoinitiator, the reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 1.04(s, 3H), 2.34 (d, 2H), 2.44 (m, 2H), 7.39 (m, 2H), 7.59 (m, 2H), 8.02 (m, 4H;

MS(m/z): 320(M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 365nm (see Figure 6 in the description), and under the irradiation of an LED point light source with a wavelength of 365nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 82%.

Example 6

(1) Methyl 2-(4-acetyl-3-methoxyphenyl)-2-oxoacetate

Dissolve 0.2 mol of methyl 2-(4-acetylphenyl)-2-oxoacetate in 200 ml of ethanol, add 45 ml of an aqueous H ₂ SO ₄ solution with a mass concentration of 65% under an ice bath, and react for 1.5 h, Then add 0.2mol sodium hydroxide, drop 50ml HCl aqueous solution with a mass concentration of 10%, then add 0.2mol CH ₃ I, 0.3g AlBr ₃ , after the reaction for 0.3h, add 20ml water, remove the organic solvent by rotary evaporation, and filter to obtain 2 -(4-formyl-3-methoxyphenyl)-2-oxyacetic acid methyl ester;

(2) 0.18mol of 2-(4-acetyl-3-methoxyphenyl)-2-oxyacetic acid methyl ester and 0.15mol of benzaldehyde are added in 30mL DMF to dissolve, and 2wt% sodium tert-butoxide ethanol solution is added to be Catalyst, adjust pH=13 or so, after reacting at 0°C for 0.5h, directly rotary-evaporate the reaction solution to obtain a viscous solid, wash with ethanol, add dichloromethane, collect the dichloromethane and rotate again to obtain a solid product, The solid product is filtered, washed, recrystallized, and dried in vacuo to finally obtain a novel methyl benzoate photoinitiator, and the reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 3.61(s, 3H), 3.90 (s,3H), 7.35(m,3H), 7.54(m,3H), 7.60(d,1H), 7.72(d,1H), 8.04(d,1H), 8.07(d,1H); MS( m/z): 324(M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 371nm (see Figure 7 in the description), and under the irradiation of an LED point light source with a wavelength of 365nm, the initiator concentration is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 77%.

Example 7

(1) Methyl 2-(4-acetyl-3-chlorophenyl)-2-oxoacetate

Dissolve 0.2 mol of methyl 2-(4-acetylphenyl)-2-oxoacetate in 300 mL of an aqueous ethanol solution with a mass concentration of 50%, continuously pass chlorine gas, add 1 g FeCl ₃ , react for 0.25 h, and remove by rotary evaporation Ethanol, filtered to obtain methyl 2-(4-acetyl-3-chlorophenyl)-2-oxoacetate;

(2) 0.18mol of 2-(4-acetyl-3-chlorophenyl)-2-oxyacetic acid methyl ester and 0.15mol of p-tolualdehyde were added to 200ml of isopropanol to dissolve, and 10wt% of diisopropylamino Lithium cyclohexane solution was used as the catalyst, pH was adjusted to about 13, and after reacting at 35°C for 0.1 h, it was rotary-evaporated to a viscous state, and dichloromethane and saturated brine were respectively added for repeated extraction, and the extract was rotary-evaporated again to obtain a solid product , the solid product is washed with a small amount of petroleum ether, vacuum-dried, finally obtains novel methyl benzoylformate class photoinitiator, and the reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 2.41(s, 3H), 3.61 (s, 3H), 7.39(d, 2H), 7.59(d, 2H), 7.60(d, 1H), 7.95(m, 3H), 8.06(d, 1H); MS(m/z): 342( M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 371 nm (see Figure 8 in the description), and under the irradiation of an LED point light source with a wavelength of 365 nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 77%.

Example 8

0.95mol of 2-(4-acetyl-3-methoxyphenyl)-2-oxyacetic acid methyl ester and 0.5mol of 2,5-diformylfuran were added to 150mL of ethanol to dissolve, with 2wt% tert-butanol Potassium ethanol solution was used as a catalyst, pH was adjusted to about 10, after 5 hours of reaction at 10 °C, the reaction product was extracted with 1:1 ethyl acetate saturated brine for several times, and the ethyl acetate phase was rotary evaporated to obtain a solid product. With n-hexane washing, vacuum drying, finally obtain novel methyl benzoylformate photoinitiator, reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 3.61(s, 6H), 3.90 (s,3H),6.93(m,3H),7.24(d,1H),7.59(m,4H),7.72(m,1H),7.80(m,2H),7.90(d,1H),8.04( d,1H);

MS(m/z): 502(M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 380 nm (see Figure 9 in the description), and under the irradiation of an LED point light source with a wavelength of 365 nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 75%.

Example 9

(1) Methyl 2-(4-acetyl-3-cyanophenyl)-2-oxoacetate

The 2-(4-acetylphenyl)-2-oxoacetate methyl ester of 0.2mol is dissolved in 300mL mass concentration in the 50% ethanol aqueous solution, and chlorine gas is continuously fed, and under the catalysis _of 1g FeCl , the reaction is carried out. 0.25h, add 1g FeCl ₃ , after 0.25h reaction, add 0.2mol sodium cyanide, after 0.5h reaction, remove ethanol by rotary evaporation, filter to obtain 2-(4-acetyl-3-cyanophenyl)-2 - methyl oxyacetate;

(2) 0.11 mol of methyl 2-(4-acetyl-3-cyanophenyl)-2-oxoacetate and 0.1 mol of 1-methyl-2-pyrrolecarboxaldehyde were added to 200 ml of tetrahydrofuran to dissolve, and 1 wt % hydrogen Potassium oxide ethanol solution was used as catalyst, pH was adjusted to about 8.5, after 4 hours of reaction at 30°C, heating was stopped, and it was cooled at room temperature. It was found that a solid was precipitated. The solid was filtered, washed with a small amount of methanol, recrystallized, and dried in vacuo to finally obtain a new type of benzene. Methyl formate photoinitiator, the reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 3.61(s, 3H), 3.90 (s,3H),6.07(m,1H),6.64(d,1H),7.15(d,1H),7.59(d,1H),7.90(d,2H),8.22(d,1H),8.32( d, 1H), 8.53 (s, 1H); MS (m/z): 322 (M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 387nm (see Figure 10 in the description), and under the irradiation of an LED point light source with a wavelength of 365nm, the concentration of the initiator is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 72%.

Example 10

(1) Methyl 2-(4-acetyl-2-methylphenyl)-2-oxoacetate

Dissolve 0.2 mol of methyl 2-(4-acetylphenyl)-2-oxoacetate in 200 ml of 80% ethanol aqueous solution, feed 0.2 mol of methyl chloride, and add 2.5 g _of AlCl Catalytic reaction, After 2h of reaction, ethanol was removed by rotary evaporation, and 2-(4-acetyl-2-methylphenyl)-2-oxoacetic acid methyl ester was obtained by filtration;

(2) 0.19 mol of methyl 2-(4-acetyl-2-methylphenyl)-2-oxyacetate and 0.1 mol of terephthalaldehyde were added to 150 mL of 80% ethanol aqueous solution to dissolve, and 2 wt % potassium tert-butoxide was added to dissolve it. The ethanol solution was used as the catalyst, and the pH was adjusted to about 11. After reacting at 25°C for 2 hours, the viscous solid was obtained by rotary evaporation, which was washed with methanol, recrystallized with ethanol, filtered, washed with methanol again, and dried in vacuum to finally obtain a new type of benzyl Methyl formate photoinitiator, the reaction equation is as follows:

The structure of the prepared novel methyl benzoylformate photoinitiator was confirmed by ¹ H-NMR and MS, ¹ H-NMR (d-DMSO, 400MHz)δ(ppm): 2.48(s, 6H), 3.61 (s, 6H), 7.29(d, 4H), 7.60(d, 2H), 7.86(s, 2H), 7.95(m, 4H), 8.06(d, 2H); MS(m/z): 538( M+1) ⁺ ;

The maximum absorption wavelength of the prepared novel methyl benzoylformate photoinitiator is 371 nm (see Figure 11 in the description), and under the irradiation of an LED point light source with a wavelength of 365 nm, the initiator concentration is 1w% by mass fraction, and the polymerization monomer The double bond conversion of bulk HDDA within 250s was 78%.

Comparative Example 1

The maximum absorption wavelength of MBF photoinitiator is 255nm (see Figure 1 in the description). Under the irradiation of LED point light source with a wavelength of 365nm, the concentration of the initiator is 1w% by mass, and the double bond conversion rate of the polymerized monomer HDDA within 250s 10%.

Taking the above ideal embodiments according to the present invention as inspiration, and through the above description, relevant personnel can make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the contents in the specification, and the technical scope must be determined according to the scope of the claims.

Claims (9)

1. A novel benzoyl formate photoinitiator is characterized by having the following chemical structural general formula:

in the general chemical structure formula, n is 1-2, and in the general formula I: 4R₂Represents a substituent on 4 arbitrary vacant positions on a benzene ring; r₁And R₂Is one of hydrogen atom, alkyl, alkenyl, alkoxy, alkynyl, hydroxyl, nitro, halogen, sulfonic group and alkyl, alkenyl, alkoxy and alkynyl which are substituted by hydroxyl, halogen, nitro, sulfonic group, cyano and amino; r₃Is one of alkyl, alkenyl, alkynyl, aryl and heterocyclic aryl.

2. The novel methyl benzoylformate photoinitiator as claimed in claim 1, having the following formula:

3. a preparation method of a novel benzoyl formate photoinitiator is characterized by comprising the following steps:

(1) first, a carbonyl-functionalized methyl benzoylformate derivative containing a bis-alphaH is prepared;

(2) the carbonyl functionalized methyl benzoylformate derivative containing double alpha H and aldehyde compounds are subjected to condensation reaction, and after the reaction is finished, the obtained solid product is purified to obtain the novel methyl benzoylformate photoinitiator.

4. The method for preparing the novel methyl benzoylformate photoinitiator according to claim 3, wherein the method comprises the following steps: the carbonyl-functionalized methyl benzoylformate derivative containing a bis alphaH has the following formula:

5. the method for preparing the novel methyl benzoylformate photoinitiator according to claim 3, wherein the method comprises the following steps: the aldehyde compound is 1-methyl-2-pyrrole formaldehyde, terephthalaldehyde, furfural, p-tolualdehyde, 2, 5-diformylfuran, 1-methyl-1H-pyrrole-2, 5-dicarboxaldehyde or benzaldehyde.

6. The method for preparing the novel methyl benzoylformate photoinitiator according to claim 3, wherein the method comprises the following steps: the molar ratio of the carbonyl functionalized methyl benzoylformate derivative containing bis alpha H to the aldehyde compound in the condensation reaction is 1-2: 1.

7. The method for preparing the novel methyl benzoylformate photoinitiator according to claim 3, wherein the method comprises the following steps: the condensation reaction is carried out at the temperature of 0-80 ℃ for 0.05-6h, and the pH value is 8-13.

8. The method for preparing the novel methyl benzoylformate photoinitiator according to claim 3, wherein the method comprises the following steps: the solvent of the condensation reaction is methanol, ethanol, isopropanol, tert-butanol, tetrahydrofuran, dimethylformamide or dimethyl sulfoxide.

9. The method for preparing the novel methyl benzoylformate photoinitiator according to claim 3, wherein the method comprises the following steps: the catalyst for the condensation reaction is sodium hydroxide, potassium hydroxide, sodium tert-butoxide, potassium tert-butoxide, sodium bicarbonate, diisopropylamine, pyridine, lithium diisopropylamide, triethanolamine, methyldiethanolamine or lithium hexamethyldisilazide.

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