WO2011145354A1 - Method for purification of 2-alkyl-2-adamantyl (meth)acrylates - Google Patents

Abstract

A method for the purification of 2-alkyl-2-adamantyl(meth)acrylates, which comprises: adding a polymerization inhibitor to a 2-alkyl-2-adamantyl (meth)acrylate; subjecting the resulting mixture to distillation; adding an alcoholic solvent to the 2-alkyl-2-adamantyl (meth)acrylate obtained by the distillation; and subjecting the mixture thus obtained to crystallization.

Description

Method for purifying 2-alkyl-2-adamantyl (meth) acrylate

The present invention relates to a method for purifying 2-alkyl-2-adamantyl (meth) acrylate.

2-Alkyl-2-adamantyl (meth) acrylate is a base material that is particularly useful as a monomer for ArF semiconductor photoresists, and is required to have higher purity as semiconductor processing becomes finer. Since an alkyl group having 1 to 3 carbon atoms can be purified by distillation, distillation purification is carried out for the purpose of removing metal components. Since these are polymerizable substances, simple distillation or thin film distillation is employed. However, as a high-purity monomer for resist, it is further required that there are few non-polymerizable impurities and heavy components as well as polymerizable impurities.

In Patent Document 1, 2-alkyl-2-adamantyl (meth) acrylate is purified by distillation. However, it is difficult to obtain a high purity by removing only components having boiling points by distillation alone.
Patent Document 2 discloses a production method for obtaining a high-purity product by performing distillation of alkyladamantyl (meth) acrylate twice. However, since the distillation operation is performed twice, it is exposed to high temperatures and has a heavy content. The risk of generating is great.

Patent Document 3 discloses a method of performing thin film distillation by adjusting the heating temperature and time.
Patent Document 4 discloses a method for obtaining a high-purity product by performing distillation in the presence of a heterocyclic compound or a basic compound. Heterocyclic compounds and basic compounds may be mixed.
Patent Document 5 discloses 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine as a decomposition inhibitor and a polymerization inhibitor. Etc. are added and purified.

JP 2003-55301 A JP 2008-297242 A Japanese Patent Laid-Open No. 2002-3448 JP 2001-328967 A JP-A-2005-120018

An object of the present invention is to provide a method for purifying 2-alkyl-2-adamantyl (meth) acrylate with less impurities.

According to the present invention, the following purification method is provided.
1.2-Alkyl-2-adamantyl (meth) acrylate is distilled by adding a polymerization inhibitor,
Crystallization by adding an alcohol solvent to the distilled 2-alkyl-2-adamantyl (meth) acrylate,
A method for purifying 2-alkyl-2-adamantyl (meth) acrylate.
2. 2. The purification method according to 1, wherein the alkyl of the 2-alkyl-2-adamantyl (meth) acrylate has 1 to 3 carbon atoms.
3. The purification method according to 1 or 2, wherein the polymerization inhibitor is methoquinone.
4). 4. The purification method according to any one of 1 to 3, wherein the alcohol solvent is methanol, ethanol, n-propanol or isopropanol.

According to the present invention, a method for purifying 2-alkyl-2-adamantyl (meth) acrylate with less impurities can be provided.

The method for purifying 2-alkyl-2-adamantyl (meth) acrylate of the present invention comprises the following two steps.
1) A polymerization inhibitor is added to 2-alkyl-2-adamantyl (meth) acrylate and distilled (distillation step).
2) Crystallize by adding an alcohol solvent to distilled 2-alkyl-2-adamantyl (meth) acrylate (crystallization step).

By adding a polymerization inhibitor to the distillation step, it is possible to suppress the formation of a polymer that is an impurity. The polymerization inhibitor can be removed in the crystallization process. Accordingly, the selection range of the type, amount and operating conditions of the polymerization inhibitor that can be used in the distillation process is widened.
Since the product is finished by crystallization, the thermal history of the final product can be relaxed, and impurities such as heavy components can be suppressed. Further, by performing crystallization, impurities having a boiling point close to each other can be removed and the purity can be increased.
From the viewpoint of relaxing the thermal history, the distillation is preferably performed once. In the present invention, a high-purity product can be obtained even by one distillation by combining with crystallization. The distillation may be simple distillation or thin film distillation, but simple distillation is preferred.

In the method of the present invention, a compound having a melting point of room temperature or higher can be easily handled as a crystalline powder. This eliminates the need for operations such as heating and melting when the product monomer is used, and it is possible to maintain the monomer quality and simplify the handling operation.

　式中、Ｒ^１１はアルキル基である。Ｒ^１２は水素原子又はメチル基である。 2-Alkyl-2-adamantyl (meth) acrylate is represented by the following formula (10).

In the formula, R ¹¹ is an alkyl group. R ¹² is a hydrogen atom or a methyl group.

2-Alkyl-2-adamantyl (meth) acrylate can be produced, for example, by the following method.
A metal 2-alkyl-2-adamantyl alcoholate represented by the formula (1) is reacted with an esterifying agent which is (meth) acrylic acid or a derivative thereof.

R ¹¹ is an alkyl group. Alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, and an isopropyl group are highly useful as raw materials for semiconductor resist materials.

M represents Li atom or -MgX. X represents a halogen atom, preferably a chlorine atom or a bromine atom from the viewpoint of easy availability of the metal compound, and most preferably a bromine atom from the viewpoint of reactivity.

Among the metal compounds of the formula (1), specific examples of the magnesium halide 2-alkyl-2-adamantyl alcoholate include magnesium chloride 2-methyl-2-adamantyl alcoholate, magnesium bromide 2-methyl-2-adamantyl alcoholate, Examples thereof include magnesium chloride 2-ethyl-2-adamantyl alcoholate and magnesium bromide 2-ethyl-2-adamantyl alcoholate. From the viewpoint of ease of production, magnesium bromide 2-methyl-2-adamantyl alcoholate is preferable.

Magnesium halide 2-alkyl-2-adamantyl alcoholate can be easily produced from 2-adamantanone and Grignard reagent.

Among the metal compounds represented by the formula (1), lithium 2-alkyl-2-adamantyl alcoholate can be produced from 2-adamantanone and alkyllithium by a known method.

For example, it can be obtained by mixing and directly reacting a solution or suspension containing 2-adamantanone and an alkyl halide (hereinafter also referred to as organic raw material liquid) and metallic lithium.

The alkyl halide is not particularly limited, and alkyl bromide, alkyl iodide, alkyl chloride and the like can be used. Alkyl chloride or alkyl bromide having an alkyl group having 1 to 6 carbon atoms is preferable because the raw material is easily available. Specific examples include 2-chloropropane, butyl chloride, pentyl chloride, hexyl chloride, methyl bromide, ethyl bromide, butyl bromide, methyl iodide, ethyl iodide and the like.
Considering the high conversion rate of 2-adamantanone, the amount of alkyl halide used is preferably 2-adamantanone: alkyl halide = 1: 1 to 1: 2 in molar ratio.

As the solvent or dispersion medium for dissolving or dispersing the 2-adamantanone and the alkyl halide, an organic solvent that is stable with respect to metallic lithium, alkyllithium, and lithium alkoxide can be used. Examples of such an organic solvent include ether solvents such as diethyl ether, tetrahydrofuran, and dioxane, hydrocarbon solvents such as hexane, benzene, and toluene, and mixed solvents thereof.

In addition, when continuing the esterification reaction mentioned later, it is preferable that almost no metallic lithium remains in the reaction liquid after completion of the above reaction. Therefore, the amount of metallic lithium added is preferably 3 mol or less, particularly 1.5 to 2.5 mol per mol of 2-adamantanone.

The reaction time for the alkylation reaction is usually 0.5 to 48 hours, although it varies depending on the addition rate of metallic lithium, the removal efficiency of reaction heat, and the like. In order to prevent the deactivation of metallic lithium, it is desirable to perform the reaction in an inert atmosphere such as argon.

As an esterifying agent, (meth) acrylic acid halide, (meth) acrylic anhydride represented by the following formula (4), or carbon atoms having double bonds at the α and β positions represented by the following formula (5): An ester compound of (8) alcohol or phenol and (meth) acrylic acid can be used.

In formulas (4) and (5), R ²⁰ represents a hydrogen atom or a methyl group. R ³⁰ , R ⁴⁰ and R ⁵⁰ represent a hydrogen atom, an alkyl group or an aryl group which may have a substituent, and R ³⁰ and R ⁴⁰ or R ⁴⁰ and R ⁵⁰ may be connected to each other to form a ring. The total number of carbon atoms of R ³⁰ , R ⁴⁰ , and R ⁵⁰ is 0-6.

Examples of the compound represented by the formula (5) include vinyl (meth) acrylate, isopropenyl (meth) acrylate, 1-cyclohexenyl (meth) acrylate, and 2,6-dimethyl-1- (meth) acrylate. Examples include cyclohexenyl, 1-phenylethenyl (meth) acrylate, phenyl (meth) acrylate, 4-nitrophenyl (meth) acrylate, and the like.

A 2-alkyl-2-adamantyl (meth) acrylate of the formula (10) can be produced by reacting the metal compound of the formula (1) with the esterifying agent. This reaction is carried out by mixing the above compounds. Use of the reaction solvent improves workability and further facilitates control of the reaction temperature.

As the solvent used in the reaction, any solvent can be used as long as it does not react with the metal compound and the esterifying agent. Specific examples include ether solvents such as ethyl ether, tetrahydrofuran (THF) and dioxane, hydrocarbon solvents such as hexane, benzene, toluene and xylene, and halogen solvents such as dichloromethane.
The concentration of the metal compound in the solvent is preferably 0.01 to 10 mol / l.
The amount of the esterifying agent used in the reaction is preferably 0.9 to 1.3 mol per 1 mol of the metal compound.

When adding an esterifying agent or a solution thereof to the metal compound solution, it is preferable to drop the metal compound solution continuously or intermittently little by little over a relatively long time while controlling the reaction temperature.

Although the reaction time varies depending on the length of the dropping time, it is usually preferably 0.5 to 6 hours after the dropping. The esterification reaction temperature is preferably −20 to 100 ° C. From the viewpoint of preventing the deactivation of the esterifying agent and the metal compound, the reaction is desirably performed in an inert atmosphere such as nitrogen or argon.

Furthermore, an ester compound can be obtained with a higher conversion rate by adding a tertiary amine compound to the reaction system during the esterification reaction. The tertiary amine compound is not particularly limited, but triethylamine, tributylamine, N-methylpiberidine, N-methylmorpholine, 1,4-diazabicyclo [2.2.2] octane, 1,7-diazabicyclo [4.3.0]. ] Cyclic or acyclic aliphatic tertiary amines such as non-6-ene and 1,8-diazabicyclo [5.4.0] undec-7-ene, dimethylaniline, pyridine, 4-dimethylaminopyridine, etc. An aromatic tertiary amine can be used. The amount of tertiary amine compound added is usually 0.01 to 0.5 equivalents relative to the metal 2-alkyl-2-adamantyl alcoholate.

In the purification method of the present invention, a polymerization inhibitor is added to crude 2-alkyl-2-adamantyl (meth) acrylate and distilled. Examples of the polymerization inhibitor include methoquinone, hydroquinone, phenothiazine, and methoxyphenothiazine. The addition amount of the polymerization inhibitor is, for example, 10 to 10,000 wtppm with respect to the crude 2-alkyl-2-adamantyl (meth) acrylate.

An adamantane compound is known as a sublimable substance. Further, alkyladamantyl (meth) acrylate is a thermally unstable compound having a polymerizable functional group. Therefore, the distillation operation in the distillation purification process is preferably performed at a temperature as low as possible under reduced pressure.
The degree of vacuum when performing the distillation operation under reduced pressure is usually 2 kPa or less, preferably 1 kPa or less, and more preferably 100 Pa or less. Further, there is no particular problem if the lower limit is not too low, but there is usually a limit due to the tightness of the distillation equipment and the performance of the vacuum pump. The degree of vacuum is preferably controlled so that the distillation temperature is within the following range.

The distillation temperature is usually 170 ° C. or lower, preferably 150 ° C. or lower, and particularly preferably 130 ° C. or lower. The lower limit is usually 20 ° C. or higher. If this temperature is too high, there may be a problem with the stability of the object. On the other hand, if the temperature is too low, the condenser must be set at a very low temperature, which is not an industrially advantageous operation.
The cooling temperature of the condenser can be arbitrarily selected, but is usually 40 ° C. or lower, preferably 30 ° C. or lower. The lower limit of the cooling temperature is −20 ° C. or higher, preferably −10 ° C. or higher. If the cooling temperature is too high, the amount of volatilization up to the cold trap will not be collected as the distillate, which is disadvantageous in terms of equipment, and if it is too low, the viscosity of the target product will increase and the distillate will flow There is a tendency to cause trouble.

The distillation operation can be carried out either batchwise or continuously. The target compound of the present invention is a thermally unstable compound, and continuous distillation is preferable from the viewpoint of shortening the residence time in the heating section and productivity. Examples of continuous distillation include flash distillation and molecular distillation.
As an industrial apparatus, it is preferable to use a thin film distillation apparatus generally used for distillation of thermally unstable compounds.

Next, an alcoholic solvent is added to the distilled 2-alkyl-2-adamantyl (meth) acrylate to cause crystallization.
The alcohol solvent is preferably one that dissolves the polymerization inhibitor. For example, methanol, ethanol, n-propanol or isopropanol, with methanol being preferred.

Crystallization is performed by cooling the solution to which the alcohol solvent has been added and holding it for a certain period of time to precipitate crystals. The crystallization conditions vary depending on the polymerization inhibitor, solvent, etc. used, but the crystallization temperature is, for example, -20 ° C to 20 ° C. The crystallization time is, for example, 0.5 to 24 hours.
The liquid part after crystallization may be extracted by, for example, decantation, and crystallization may be performed a plurality of times. Further, crystallization may be performed by adding a small amount of seed crystals to the solution. Crystallization may be performed once or twice or more.

Synthesis example 1
Under a nitrogen atmosphere, 450 g of tetrahydrofuran (THF) was added to 150 g (1.0 mol) of 2-adamantanone and dissolved. Here, 1100 ml (1.1 mol) of a THF solution (1.0 mol / l) of methylmagnesium bromide was added dropwise so that the reaction solution temperature did not exceed 40 ° C. After completion of the dropping, the mixture was stirred for 1 hour to obtain a THF solution of magnesium bromide 2-methyl-2-adamantyl alcoholate. To this was added dropwise 125 g (0.24 mol) of methacrylic acid chloride so that the reaction solution temperature did not exceed 40 ° C. After completion of dropping, the mixture was stirred at room temperature for 4 hours. Next, 50 g of methanol and 80 g of a 10% aqueous sodium hydroxide solution were added while maintaining the liquid temperature at 10 ° C. or lower and stirred for 1 hour, and then the organic layer was separated. The organic layer was further washed with a 10% aqueous sodium hydroxide solution, and the solvent was distilled off under reduced pressure to obtain 115 g of crude 2-methyl-2-adamantyl methacrylate (crude yield 49%) (crude monomer A).

Example 1
Add 0.2% of methoquinone as a polymerization inhibitor to the crude 2-methyl-2-adamantyl methacrylate obtained in Synthesis Example 1 and perform simple distillation under reduced pressure of 0.3 mmHg at 85 ° C. to 90 ° C. -101 g of methyl-2-adamantyl methacrylate (recovery rate 88%) (GC (gas chromatography) purity 99.0%) was obtained.
200 g of methanol is added to 200 g of the above-purified 2-methyl-2-adamantyl methacrylate to make a solution, then cooled to −10 ° C., a small amount of seed crystals are added, and the mixture is kept at −10 ° C. for 2 hours. Crystallization was performed. Decant and extract 200 g of liquid, add 200 g of methanol to this, dissolve at 20 ° C., cool to −10 ° C., add a small amount of seed crystals, and hold at −10 ° C. for 2 hours. Was crystallized. After extracting the liquid part, the crystal was returned to room temperature and dissolved, and concentrated under reduced pressure at 20 ° C. while bubbling dry air through a capillary to obtain 134.0 g of high-purity 2-methyl-2-adamantyl methacrylate (GC purity 99 9%, 67% recovery) (purified monomer A). The high purity 2-methyl-2-adamantyl methacrylate had a melting point of 12.6 to 13.1 ° C. (differential scanning calorimetry (DSC)).

Synthesis example 2
Under nitrogen atmosphere, Li3.05g (0.44mol) was added in THF200ml, and it stirred for 1 hour. Into this, a solution prepared by dissolving 30 g (0.2 mol) of 2-adamantanone and 25.8 g (0.33 mol) of 2-chloropropane in 100 ml of THF was added dropwise over 30 minutes while maintaining the temperature to be 20 ° C. or lower. . After dropping, the mixture was stirred at 20 ° C. for 90 minutes to obtain a THF solution of lithium 2-isopropyl-2-adamantyl alcoholate. To this, 36.2 g (0.24 mol) of methacrylic anhydride was added dropwise over 15 minutes while cooling so as to keep the temperature at 20 ° C. or lower, and then stirred at 20 ° C. for 60 minutes to give 2-isopropyl-2-adamantyl. Methacrylate was synthesized. After the reaction, 400 ml of diethyl ether was added, 200 ml of 0.2N NaOH was added, and the mixture was stirred at 20 ° C. for 60 minutes to remove the aqueous phase, followed by washing with 200 ml of pure water twice. The solvent was distilled off under reduced pressure at 25 ° C. to obtain 52.7 g of crude 2-isopropyl-2-adamantyl methacrylate (crude yield 101%, GC purity 83.0%, GPC purity 83.0%). (Crude monomer D).

Example 2
To the crude 2-isopropyl-2-adamantyl methacrylate obtained in Synthesis Example 2, 0.07 g of methoquinone was added as a polymerization inhibitor, and simple distillation was performed at 100 to 120 ° C. while bubbling dry air through a capillary. 36.9 g (0.14 mol, GC purity 86.9%, GPC (gel permeation chromatography) purity 97.1%, methoquinone content 0.2%) of purified 2-isopropyl-2-adamantyl methacrylate was obtained.

To 36.9 g of the above-purified 2-isopropyl-2-adamantyl methacrylate, 79 ml of methanol was added and dissolved, cooled to 0 ° C., a small amount of seed crystals were added, and the mixture was kept at 0 ° C. for 12 hours for crystallization. Went. This was filtered, recovered and dried under reduced pressure at 25 ° C., and 32.1 g of high purity 2-isopropyl-2-adamantyl methacrylate (0.12 mol, crystallization recovery rate 87%, GC purity 99.5%, GPC purity 99. 9%) was obtained (purified monomer D). The total yield including synthesis example 2 was 61%. This high purity 2-isopropyl-2-adamantyl methacrylate had a melting point of 37.7 to 40.6 ° C. (DSC).

Reference example 1
In methyl isobutyl ketone, 2,2′-azobis (isobutyric acid) dimethyl / crude monomer A / monomer B / monomer C of Synthesis Example 1 at a weight ratio of 0.1 / 1.0 / 1.0 / 1.0 The mixture was stirred and stirred for 2 hours under reflux. After that, the reaction solution was purified by pouring it into a large amount of methanol / water mixed solvent and precipitating three times. As a result, copolymer composition (mol) = 23: 44: 33 of crude monomer A: monomer B: monomer C, a weight average molecular weight (Mw) of 8800, and a degree of dispersion (Mw / Mn) of 2.47 P1 was obtained. The results are shown in Table 1.

Reference example 2
The reaction was performed in the same manner as in Reference Example 1 except that the crude monomer A was changed to the purified monomer A of Example 1. As a result, copolymer P2 of copolymerization composition (mol) of purified monomer A: monomer B: monomer C = 25: 46: 29, weight average molecular weight (Mw) is 7900, and dispersity (Mw / Mn) is 2.41. Got. The results are shown in Table 1.

Reference example 3
The reaction was performed in the same manner as in Reference Example 1 except that the crude monomer A was changed to the crude monomer D synthesized in Synthesis Example 2. As a result, the copolymer composition (mol) of the crude monomer D: monomer B: monomer C in Synthesis Example 2 = 20: 47: 33, the weight average molecular weight (Mw) is 8600, and the degree of dispersion (Mw / Mn) is 2.51. The copolymer P3 was obtained. The results are shown in Table 1.

Reference example 4
The reaction was performed in the same manner as in Reference Example 1 except that the crude monomer A was changed to the purified monomer D of Example 2. As a result, copolymer P4 of purified monomer D: monomer B: monomer C copolymer composition (mol) = 21: 46: 33, weight average molecular weight (Mw) 7800, dispersity (Mw / Mn) 2.45 Got. The results are shown in Table 1.

Evaluation Example 1
To the above copolymer (P1), 5 wt% of triphenylsulfonium nonafluorobutane sulfonate is added as a photoacid generator, and dissolved in propylene glycol monomethyl ether acetate so that these are 10 wt% to prepare a resist composition R1 did. The prepared resist composition was applied onto a silicon wafer and baked at 110 ° C. for 60 seconds to form a resist film. In the same manner, a resist composition R2 is prepared from the copolymer (P2), a resist composition R3 is prepared from the copolymer (P3), and a resist composition R4 is prepared from the copolymer (P4). Formed.

Each of these resist films was spin-coated on a silicon wafer subjected to HMDS (hexamethyldisilazane) treatment, and heated at 100 ° C. for 180 seconds to form a thin film. Next, the substrate having this thin film is drawn using an electron beam drawing apparatus (acceleration voltage 50 kV), baked at 100 ° C. for 60 seconds, and then developed with an aqueous tetrabutylammonium solution having a concentration of 2.38 wt% for 60 seconds. After processing, washing with pure water for 60 seconds, and then drying with a nitrogen stream, a 100 nm line and space pattern was produced. When the obtained patterns were observed with a scanning electron microscope, no defects such as unsolved residues could be observed in the resist compositions R2 and R4, but unsolved in the resist compositions R1 and R3. And other defects were observed.

The 2-alkyl-2-adamantyl (meth) acrylate obtained by the method of the present invention includes a photoresist for semiconductor, a sealing agent for optical semiconductor, an optical electronic member (optical waveguide, optical communication lens, optical film, etc.) and It can be used as these adhesives.

Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will appreciate that these exemplary embodiments and / or embodiments are substantially without departing from the novel teachings and advantages of the present invention. It is easy to make many changes to the embodiment. Accordingly, many of these modifications are within the scope of the present invention.
The entire contents of the documents described in this specification are incorporated herein by reference.

Claims (4)

2-alkyl-2-adamantyl (meth) acrylate, distilled with a polymerization inhibitor,
Crystallization by adding an alcohol solvent to the distilled 2-alkyl-2-adamantyl (meth) acrylate,
A method for purifying 2-alkyl-2-adamantyl (meth) acrylate. The purification method according to claim 1, wherein the alkyl of the 2-alkyl-2-adamantyl (meth) acrylate has 1 to 3 carbon atoms. The purification method according to claim 1 or 2, wherein the polymerization inhibitor is methoquinone. The purification method according to any one of claims 1 to 3, wherein the alcohol solvent is methanol, ethanol, n-propanol or isopropanol.