KR102740005B1 - Diphenyliodonium salts used as photoinitiator and producing method thereof - Google Patents

Abstract

The present invention relates to a method for preparing an ionic UV photoinitiator comprising an iodonium salt.

Description

{Diphenyliodonium salts used as photoinitiator and producing method thereof}

The present invention relates to a high-purity diphenyliodonium salt used as a photoinitiator and a method for producing the same.

A photoinitiator is a substance that is added to UV-curable paints to absorb light and decompose to create chemically active atoms or molecules, and refers to a substance that absorbs energy from an UV light source and initiates a polymer reaction. Photoinitiators are generally used with various compounds containing acrylic or epoxy reactors, and their representative industrial applications include hard coatings that make plastic surfaces with weak physical properties harder, adhesives that bond materials by receiving UV, and UV-curable paints.

A substance useful as such a UV photoinitiator is diphenyliodonium salt. Diphenyliodonium salt has the advantage of not only acting as a photoinitiator, but also improving adhesive performance and moisture-proofing function.

Despite these advantages of diphenyliodonium salts, diphenyliodonium salts manufactured by conventional methods have a dark brown color, making them difficult to apply in fields requiring colorless transparency.

Republic of Korea registered patent 10-0753350

The present invention aims to develop a method for producing a high-purity diphenyliodonium salt and the same by selectively extracting and removing impurities that may affect the color of the final material without affecting the physical characteristics and recovery rate of the diphenyliodonium salt to solve the above problems.

In order to achieve the above object, the present invention provides a method for producing a diphenyliodonium salt of the following chemical formula 1, which comprises a step of separating and purifying diphenyliodonium sulfate obtained as a reaction intermediate in producing a diphenyliodonium salt of the following chemical formula 1 by reacting phenyliodine having an R1 substituent and benzene having an R2 substituent.

[Chemical Formula 1]

In the above formula, A ^- represents a counter anion other than sulfate,

R1 and R2 are each independently a straight-chain or branched-chain alkyl having 1 to 6 carbon atoms.

In addition, the present invention provides a diphenyliodonium salt of chemical formula 1 having a purity of 95% or more as measured by anion ion chromatography.

The present invention provides a diphenyliodonium salt of chemical formula 1 having a Gardner color value of 3 to 8.

The present invention relates to a composition having a purity of 95% or more as measured by anion ion chromatography or a Gardner color value of 3 to 8. A photoinitiator comprising a diphenyliodonium salt of chemical formula 1 is provided.

The diphenyliodonium salt of the present invention having a purity of 95% or higher as measured by anion ion chromatography or a Gardner color value of 3 to 8 has the advantage of being colorless when used as a photoinitiator and thus can be utilized in fields requiring transparency.

The method for producing a diphenyliodonium salt of the present invention has the effect of providing a high-purity diphenyliodonium salt, and as a result, has the advantage of being able to be used in fields requiring a transparent photoinitiator.

Figure 1 is an ion chromatography of diphenyliodonium hexafluorophosphate.
Figure 2 is an ion chromatography of diphenyliodonium difluorophosphate.
Figure 3 is an ion chromatography of diphenyliodonium fluorosulfonylimide.

Hereinafter, the present invention will be described in detail. The terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best way.

Diphenyliodonium salt of chemical formula 1 is conventionally prepared by a one-pot reaction, but side reactions occur during this process, making it difficult to obtain the final product pure.

Accordingly, the inventors of the present invention have attempted to provide a high-purity diphenyliodonium salt by selectively extracting and removing impurities that can affect the color of the final material without affecting the physical characteristics and recovery rate of the diphenyliodonium salt, and have attempted to develop a method for manufacturing the same. The present invention is not a one-pot reaction, but has developed a purification technology capable of selectively dissolving only molecules that cause color development by separating and extracting intermediate compounds, thereby developing a diphenyliodonium salt with high long-term storage stability while preserving the existing physical characteristics of the diphenyliodonium salt, thereby completing the present invention.

The present invention provides a method for producing a diphenyliodonium salt of the following chemical formula 1, which comprises the step of separating and purifying a sulfate of diphenyliodonium obtained as a reaction intermediate in producing a diphenyliodonium salt of the following chemical formula 1 by reacting phenyliodine having an R1 substituent and benzene having an R2 substituent.

[Chemical Formula 1]

In the above formula, A ^- represents a counter anion other than sulfate,

R1 and R2 are each independently a straight-chain or branched-chain alkyl having 1 to 6 carbon atoms.

In one embodiment, the counter anion is preferably one selected from the following group of anions, which has the advantage of excellent photoinitiator function and applicability in various fields.

[Anion group]

The method for producing the compound of chemical formula 1 of the present invention is specifically

Step 1. A step of producing di(alkylphenyl)iodonium sulfate of chemical formula 4 by reacting a compound of chemical formula 2 below and a compound of chemical formula 3 below in the presence of a persulfate.

Chemical Formula 2 Chemical Formula 3 Chemical Formula 4

Step 2. A step of separating and purifying di(alkylphenyl)iodonium sulfate of chemical formula 4, and

Step 3. A step of reacting the purified di(alkylphenyl)iodonium sulfate of chemical formula 4 with an anion salt to produce a compound of chemical formula 1.

Chemical Formula 4 Chemical Formula 1

In the above chemical formula 4, M is a monovalent cation,

In chemical formula 1, A ^- is a counter anion other than sulfate,

R1 and R2 are each independently a straight or branched chain alkyl having 1 to 6 carbon atoms.

The anionic salt of step 3 above is a metal or non-metal salt of the A ^- anion.

In one embodiment of the present invention, R1 and R2 can each independently be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, etc.

In one embodiment of the present invention, R1 may be methyl and R2 may be isobutyl.

In one embodiment of the present invention, the compound of chemical formula 1 may be a compound of chemical formula 5 below.

[Chemical Formula 5]

In step 1, the reaction can proceed in the presence of an acid and a solvent, and the solvent is preferably at least one selected from water and alcohol.

The acid is one or more selected from the group consisting of sulfuric acid; carboxylic acid such as acetic acid and citric acid; nitric acid; phosphoric acid; and halogen acid such as hydrochloric acid and hydrofluoric acid, which can be used without limitation as long as it is soluble in water or alcohol. In step 1, when 1 equivalent of the compound of formula 2 is reacted with 1 equivalent to 1.5 equivalents of the compound of formula 3, the intermediate can be smoothly produced.

In step 1, a persulfate is used to promote the reaction and produce a sulfate of an intermediate, di(alkylphenyl)iodonium. In the present invention, the persulfate preferably includes ammonium persulfate, potassium persulfate, sodium persulfate, and the like. When ammonium persulfate, potassium persulfate, or sodium persulfate is used as the persulfate, di(alkylphenyl)iodonium ammonium sulfate, di(alkylphenyl)iodonium potassium sulfate, and di(alkylphenyl)iodonium sodium sulfate are obtained, respectively. The persulfate can be used in an amount of 1.5 to 2 equivalents per 1 equivalent of the compound of chemical formula 2, and in this case, di(alkylphenyl)iodonium sulfate of chemical formula 4 can be produced in a high yield.

Step 1 can be performed at -15°C to 50°C.

Step 2 is a step of separating the di(alkylphenyl)iodonium sulfate of chemical formula 4 manufactured as an intermediate and removing impurities, especially impurities that impart color to the final product. Step 2 is a step of washing using a solvent that dissolves impurities while not dissolving the di(alkylphenyl)iodonium sulfate of chemical formula 4.

The solvent for dissolving the above impurities can be a hydrocarbon having 4 to 10 carbon atoms, toluene, acetonitrile, 1,2-dichloroethane, acetone, an alcohol having 3 to 10 carbon atoms (isopropyl alcohol, butyl alcohol, isobutyl alcohol, etc.), an ether (isopropyl ether, tert-butyl methyl ether, tetrahydrofuran, etc.), an acetate solvent (ethyl acetate, butyl acetate, etc.).

The solvent is preferably a hydrocarbon having 4 to 10 carbon atoms.

The above solvent can be used in an amount of 90 mL to 300 mL per 100 g of di(alkylphenyl)iodonium sulfate of chemical formula 4, and the purification step can be performed at once, or can be performed by dividing the solvent and repeating the process two or more times.

The above step 2 can facilitate the removal of impurities if carried out at 0 to 50°C.

By proceeding through step 2, di(alkylphenyl)iodonium sulfate of chemical formula 4, which was light yellow, is obtained as a white solid.

Step 3 is a step of reacting the purified di(alkylphenyl)iodonium sulfate of chemical formula 4 with a metal or non-metal salt of the anion to finally obtain a useful compound of chemical formula 1. The metal or non-metal contained in the metal or non-metal salt of the anion may be a Group 1 element including Li, Na, K, etc., and may also be a Group 2 element including Be, Mg, Ca, etc. In addition, it may be an ammonium salt including nitrogen (N) and may be a sulfonium salt including sulfur (S).

The metal or non-metal salt of the anion can be reacted in an amount of 0.5 equivalents or more and 4 equivalents or less with respect to 1 equivalent of di(alkylphenyl)iodonium sulfate of chemical formula 4, preferably 1 equivalent or more and 1.5 equivalents or less. When the metal or non-metal salt of the anion is reacted in the equivalent range, the yield can be increased in the subsequent purification process, and after the reaction is completed, no residue remains, so it can have an excellent effect of increasing the purity.

Step 3 can be carried out in a solvent, and the solvent can be preferably one or two or more selected from water, ethyl acetate, butyl acetate, toluene, chloroform, dichloromethane, dichloroethane, tetrahydrofuran, acetonitrile, nitrile, ether, alcohol, carbonate solvents, etc.

In one embodiment of the present invention, in order to remove unreacted substances, side substances, and other foreign substances generated in the step of reacting di(alkylphenyl)iodonium sulfate of the chemical formula 4 with a metal or non-metal salt of an anion, a filtration or purification step may be additionally included after step 3. After step 3, a purification process of washing the organic phase with water may be performed.

The reaction temperature of step 3 may be -50°C or higher and 100°C or lower, preferably -20°C or higher and 50°C or lower, more preferably -10°C or higher and 30°C or lower, and even more preferably -10°C or higher and 15°C or lower.

When the above range is present, it has the effect of suppressing unreacted substances and preventing the production of by-products. In addition, the color of the product can be easily removed in the process of purifying the reactant, which can be considered an advantage according to the embodiment of the present invention.

The present invention provides a diphenyliodonium salt of the following chemical formula 1, which is manufactured by including the purification step of the present invention and has a purity of 95 wt% or more as measured by anion ion chromatography.

The present invention provides a diphenyliodonium salt of the following chemical formula 1, which is manufactured by including the purification step of the present invention and has a Gardner color value of 3 to 12, preferably 3 to 8, more preferably 3 to 6.

[Chemical Formula 1]

In the above formula, A ^- represents a counter anion other than sulfate,

R1 and R2 are each independently a straight-chain or branched-chain alkyl having 1 to 6 carbon atoms.

The above counter anion is preferably one selected from the following anion group.

[Anion group]

The compound of the above chemical formula 1 is preferably a compound of the following chemical formula 5.

[Chemical Formula 5]

In the above formula, A ^- represents a counter anion, preferably PF ₆ , PO ₂ F ₂ , bis(oxalato)borate (BOB) or bisfluorosulfonylimide (FSI).

In the present invention, when the counter anion in the compound of chemical formula 5 is PF _{6 ,} there is an advantage of being able to harden the raw material by acid generation, and when it is PO ₂ F ₂ , there is an advantage of particularly excellent thermal stability and long-term stability. In addition, when the counter anion in the compound of chemical formula 5 is bisfluorosulfonylimide (FSI), there is an advantage of being able to exist in a liquid phase because of low viscosity and high thermal stability.

In addition, the present invention provides a photoinitiator comprising a diphenyliodonium salt of chemical formula 1 having a purity of 95 wt% or more as measured by anion ion chromatography or a Gardner color value of 3 to 12, preferably 3 to 8, more preferably 3 to 6. The diphenyliodonium salt of the present invention has high purity and can be used in fields requiring transparency when used as a photoinitiator. In addition, when in a liquid state, it has the advantages of being easy to mix with other components, having excellent stability depending on the type of counter anion, and being able to be used under various conditions.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited thereto.

[Example]

Example 1.

Preparation of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate

15 g of water and 47 g (0.79 mol) of acetic acid are introduced into a 1000 ml flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen supply. The mixture is then cooled to -5 to -10°C. 45 g (0.45 mol) of sulfuric acid is slowly added dropwise so that the temperature does not exceed 15°C. The mixture is cooled to 0 to 5°C and stirred for 1 hour. 94 g (0.41 mol) of ammonium peroxodisulfate is added little by little so that the temperature does not exceed 5°C. The heterogeneous mixture is stirred at a temperature of 5°C or lower for 1 hour. Then, a mixture of 50 g (0.23 mol) of 4-iodotoluene and 37 g (0.27 mol) of isobutylbenzene is slowly added dropwise so that the temperature does not exceed 15°C. The reaction mixture is stirred at room temperature for 24 hours. After the reaction is completed, add 380 g of water, 38 g of ammonium chloride, and 10 g of heptane at room temperature and stir for 1 hour. Filter the mixture and remove the solvent under vacuum. 98.2 g (0.21 mol; 92%; Gardner value 6.7) of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate is obtained in the form of a pale yellow solid.

<Gardner color value measurement>

Device used: PFX-I Series Spectrocolorimeter

Analysis method: Dissolve 10 g of the analysis sample in 10 g of solvent, place the solution in a dedicated analysis container, and analyze.

Example 2.

Example 2-1.

Purification of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate

In Example 1, (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate (Gardner value 6.7) and 100 ml of heptane are placed in a flask and stirred at room temperature for 1 hour. The dispersed mixture is filtered to obtain a solid compound. This process is repeated twice to finally obtain 95 g (0.20 mol; 89%, Gardner value 2.0) of a white solid (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate.

Example 2-2

Purification of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate 2

A compound was prepared in the same manner as in Example 2-1, except that toluene was used instead of heptane used in Example 2-1. 92.8 g (0.19 mol; 87%; Gardner value 2.1) of a colorless, transparent white solid (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate was obtained.

Example 2-3

Purification of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate 3

A compound was prepared in the same manner as in Example 2-1, except that butylacetate was used instead of heptane. 83 g (0.18 mol; 82%) of a colorless, transparent white solid (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate was obtained.

Example 2-4

Purification of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate 4

It was prepared in the same manner as Example 2-1, except that acetone was used instead of heptane used in Example 2-1. 71 g (0.15 mol; 67%) of colorless, transparent white solid (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate was obtained.

Example 3:

Preparation of (4-isobutylphenyl)-p-tolyl-iodonium hexafluorophosphate

In Example 2-1, 95 g (0.20 mol) of purified (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate is introduced into a 1000 mL flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen supply. Then, 160 g of water and 140 g of butyl acetate are added, and the mixture is cooled to 10 to 15°C. 55 g (0.29 mol) of potassium hexafluorophosphate is added in portions so as not to exceed 15°C, and the mixture is stirred for 4 hours. The mixture is filtered, the phases are separated, and the organic phase is recovered. The organic phase is washed with water, and the solvent is removed under vacuum. 95.2 g (yield: 94%) of (4-isobutylphenyl)-p-tolyl-iodonium hexafluorophosphate is obtained in the form of a colorless transparent liquid. The substance was confirmed by ion chromatography of Fig. 1. The purity of the substance confirmed by ionotropy was 98% and the Gardner color value was 6.0.

<Ion chromatography>

Anion column used: DIonex IonpacTM AS20

Analysis is performed by dissolving 0.1 g of the sample in a solution of 45 g of distilled water and 5 g of methanol.

Comparative Example 1:

Preparation of (4-isobutylphenyl)-p-tolyl-iodonium hexafluorophosphate by ONE-POT reaction

15 g of water and 47 g (0.79 mol) of acetic acid are introduced into a 1000 ml flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen supply. The mixture is then cooled to -5 to -10°C. 45 g (0.45 mol) of sulfuric acid is slowly added dropwise so that the temperature does not exceed 15°C. The mixture is cooled to 0 to 5°C and stirred for 1 hour. 94 g (0.41 mol) of ammonium peroxodisulfate is added little by little so that the temperature does not exceed 5°C. The heterogeneous mixture is stirred at a temperature of 5°C or lower for 1 hour. Then, a mixture of 50 g (0.23 mol) of 4-iodotoluene and 37 g (0.27 mol) of isobutylbenzene is slowly added dropwise so that the temperature does not exceed 15°C. The reaction mixture is stirred at room temperature for 24 hours.

After that, 55 g (0.29 mol) of potassium hexafluorophosphate is added in portions so as not to exceed 15℃, and stirred for 4 hours. The mixture is filtered, the phases are separated, and the organic phase is recovered. The organic phase is washed with water, and the solvent is removed under vacuum. 101.28 g (yield: 89%) of (4-isobutylphenyl)-p-tolyl-iodonium hexafluorophosphate was obtained. The Gardner color value is 12.7.

Example 4:

Preparation of (4-isobutylphenyl)-p-tolyl-iodonium difluorophosphate

A compound was prepared in the same manner as in Example 3, except that 32.25 g (0.30 mol) of lithium difluorophosphate was used instead of potassium hexafluorophosphate used in Example 3. 88.81 g (yield: 96%) of (4-isobutylphenyl)-p-tolyl-iodonium, difluorophosphate was obtained in the form of a colorless transparent liquid. The substance was identified by ion chromatography of Fig. 2. The purity of the substance identified by ion chromatography was 99% and the Gardner color value was 4.1.

Example 5:

Preparation of (4-isobutylphenyl)-p-tolyl-iodonium bisfluorosulfonylimide

A mixture was prepared in the same manner as in Example 3, except that 59.23 g (0.30 mol) of bisfluorosulfonylimide ammonium salt was used instead of the potassium hexafluorophosphate used in Example 3. 103.06 g (yield: 95%) of (4-isobutylphenyl)-p-tolyl-iodonium, bisfluorosulfonylimide salt was obtained in the form of a colorless transparent liquid. The substance was identified by ion chromatography in Fig. 3. The purity of the substance identified by ion chromatography was 99% and the Gardner color value was 3.6.

Comparative Example 2:

Preparation of (4-isobutylphenyl)-p-tolyl-iodonium hexafluorophosphate

98.2 g (0.21 mol; 92%; Gardner value 6.7) of (4-isobutylphenyl)-p-tolyl-iodonium ammonium sulfate prepared in Example 1 was prepared in the same manner as in Example 3, omitting the purification process of Example 2. 95.29 g (yield: 91%) of (4-isobutylphenyl)-p-tolyl-iodonium hexafluorophosphate was obtained in the form of a dark brown transparent liquid. The purity was 98% and the Gardner color value was 12.2.

Claims (12)

A method for producing a diphenyliodonium salt of the following chemical formula 1, comprising the step of separating and purifying diphenyliodonium sulfate obtained as a reaction intermediate in producing a diphenyliodonium salt of the following chemical formula 1 by reacting phenyliodine having an R1 substituent and benzene having an R2 substituent,
[Chemical Formula 1]

Step 1. A step of producing di(alkylphenyl)iodonium sulfate of the following chemical formula 4 by reacting a compound of the following chemical formula 2 and a compound of the following chemical formula 3 in the presence of a persulfate.

Chemical Formula 2 Chemical Formula 3 Chemical Formula 4
Step 2. A step of separating and purifying di(alkylphenyl)iodonium sulfate of chemical formula 4, and
Step 3. A step of reacting the purified di(alkylphenyl)iodonium sulfate of chemical formula 4 with an anion salt to produce a compound of chemical formula 1,

Chemical Formula 4 Chemical Formula 1
In the above chemical formula 4, M is a monovalent cation,
R1 and R2 are each independently a straight or branched chain alkyl having 1 to 6 carbon atoms.
The anionic salt of the above step 3 is a metal or non-metal salt of A ^- counter anion,
In the above chemical formula 1, the A ^- counter anion is one selected from the following anion group or PO ₂ F ₂ ,
[Anion group]

The above step 2 is a method for producing a diphenyliodonium salt of chemical formula 1, wherein the di(alkylphenyl)iodonium sulfate of chemical formula 4 is purified in one or more solvents selected from the group consisting of a hydrocarbon having 4 to 10 carbon atoms, toluene, acetonitrile, 1,2-dichloroethane, acetone, an alcohol having 3 to 10 carbon atoms, ether, and an acetate solvent. delete delete In claim 1, step 1 is a method for producing a diphenyliodonium salt of chemical formula 1, which is performed in the presence of one or two solvents selected from the group consisting of water and alcohol. delete In claim 1, a method for producing a diphenyliodonium salt of chemical formula 1, wherein R1 and R2 are each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl or isopentyl A method for producing a diphenyliodonium salt of chemical formula 1 in claim 6, wherein R1 is methyl and R2 is isobutyl A diphenyliodonium salt of the following chemical formula 1, manufactured by the method of claim 1, having a purity of 95% or higher as measured by anion ion chromatography and a Gardner color value of 3 to 8.
[Chemical Formula 1]

In the above formula, A ^- is a counter anion, and is one selected from the following anion group or PO ₂ F ₂ ,
[Anion group]

R1 and R2 are each independently a straight-chain or branched-chain alkyl having 1 to 6 carbon atoms. In claim 8, a diphenyliodonium salt of chemical formula 1 wherein R1 is methyl and R2 is isobutyl delete In claim 8, A ^- a diphenyliodonium salt of formula 1, wherein the counter anion is PF ₆ , PO ₂ F ₂ , bis(oxalato)borate (BOB) or fluorosulfonylimide (FSI). Photoinitiator comprising diphenyliodonium salt of chemical formula 1 of claim 8