JP2014076989A - Method for producing glycidyl acrylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing glycidyl acrylate, which sufficiently suppresses the radical polymerization of glycidyl acrylate in a vapor phase part, also suppresses the formation of a polymer by ring opening of epoxy part, and allows a stable continuous operation for a long period of time.SOLUTION: The method for producing glycidyl acrylate includes a step for purifying the glycidyl acrylate by using a nitroso compound and a radical polymerization inhibitor different from nitroso compounds.

Description

The present invention relates to a method for producing glycidyl acrylate. More specifically, the present invention relates to a production method suitable for producing glycidyl acrylate used in a wide range of fields as a monomer raw material for paints, adhesives, pressure-sensitive adhesives, fiber modifiers, dispersants, resist materials, and the like.

Glycidyl acrylate is a kind of acrylic ester containing an epoxy group. An acrylic ester containing an epoxy group is useful as a reactive monomer and the like, and is used in a wide range of fields as a monomer raw material for paints, adhesives, adhesives, fiber modifiers, dispersants, resist materials, and the like.

Acrylic acid ester is a compound having the property of being very easily polymerized due to its structure. Moreover, since distillation purification of acrylic acid esters constitutes a system in which the gas phase part and the liquid phase part coexist, the polymerization is effective for both the liquid phase part and the gas phase part in the distillation column. It is necessary to suppress it and to enable stable continuous operation for a long time. Conventionally, in order to prevent the occurrence of such polymerization, various radical polymerization inhibitors are added singly or in combination, and added to the monomer to prevent the generation of a polymer in the production process ( For example, see Patent Documents 1 to 3).

JP 2001-348358 A JP 2001-348359 A JP 2008-222610 A

Glycidyl acrylate is a kind of acrylic ester containing an epoxy group, and has two reactive groups, an acryloyl group and an epoxy group, and thus has a property of being extremely easily polymerized. Conventionally, radical polymerization inhibitors have been used as described above during distillation purification of acrylic acid esters. However, in the distillation purification of glycidyl acrylate, radical polymerization in the gas phase is suppressed even when the polymerization inhibitor is used. Is not sufficient, and there is also a problem that a polymer is formed due to ring opening of the epoxy site.

The present invention has been made in view of the above situation, and sufficiently suppresses the radical polymerization of glycidyl acrylate in the gas phase part, suppresses the formation of a polymer due to the ring opening of the epoxy site, and is stable for a long time. It aims at providing the manufacturing method of glycidyl acrylate which can be drive | operated.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have used radical polymerization of glycidyl acrylate by using a nitroso compound and a radical polymerization inhibitor different from the nitroso compound when purifying glycidyl acrylate. In addition to the above, it has been found that the formation of a polymer by ring opening of an epoxy site can be effectively suppressed. Conventionally, nitroso compounds are compounds that have been used as radical polymerization inhibitors. By using a combination of a nitroso compound and a radical polymerization inhibitor that is different from the nitroso compound, in addition to radical polymerization, a cation by ring opening of the epoxy moiety is used. It is a finding for the first time in the present invention that the progress of polymerization is also effectively suppressed. And, by including such a purification step, the inventors have found that the method for producing glycidyl acrylate becomes a production method capable of stable continuous operation for a long time, and conceived that the above problems can be solved brilliantly, The present invention has been achieved.

That is, the present invention is a method for producing glycidyl acrylate, wherein the production method includes a step of purifying glycidyl acrylate using a nitroso compound and a radical polymerization inhibitor different from the nitroso compound. This is a method for producing glycidyl acrylate.
Further, the present invention is the method for producing glycidyl acrylate, wherein the nitroso compound is a nitrosophenyl compound or a nitrosamine compound.
The present invention is also the method for producing glycidyl acrylate, wherein the radical polymerization inhibitor is an alkylphenol compound.
Furthermore, the present invention provides the method for producing glycidyl acrylate, wherein the purification step includes a step of performing rectification by introducing a decomposition gas of a nitroso compound into a rectification column.

The present invention is described in detail below.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

The method for producing glycidyl acrylate of the present invention includes a step of purifying glycidyl acrylate using a nitroso compound and a radical polymerization inhibitor different from the nitroso compound.
In the present specification, the “radical polymerization inhibitor different from the nitroso compound” is also simply referred to as “radical polymerization inhibitor” or “polymerization inhibitor”.

Examples of the nitroso compound include nitrosophenyl compounds such as nitrosobenzene, p-nitrosophenol and p-nitrosotoluene; nitrosamine compounds such as N-nitrosodiphenylamine, N-nitrosophenylhydroxylamine and salts thereof; and the like. . From the viewpoint that the polymerization inhibitory effect of glycidyl acrylate is more excellent, nitrosobenzene, N-nitrosophenylhydroxylamine and salts thereof are preferable, and N-nitrosophenylhydroxylamine and salts thereof are more preferable.
Examples of the salt among the nitrosamine compounds include alkali metal salts, alkaline earth metal salts, ammonium salts, and the like. An ammonium salt is preferable because it is inexpensive and easily available.

Examples of the radical polymerization inhibitor different from the nitroso compound include alkylphenol compounds, paraphenylenediamines, amine compounds, copper dialkyldithiocarbamate, N-oxyl compounds, and decomposition products thereof. These compounds can be used alone or in combination of two or more.
Of the radical polymerization inhibitors different from the above nitroso compounds, alkylphenol compounds and amine compounds are preferable, and alkylphenol compounds are more preferable because the polymerization inhibition effect of glycidyl acrylate is more excellent. In the production of glycidyl acrylate, it is particularly effective to use an alkylphenol compound.

Examples of the alkylphenol compounds include methyl hydroquinone, tert-butyl hydroquinone, 2,6-di-tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone, and 2,4-dimethyl-6-tert-butyl phenol. 2,2-di-tert-butyl-4-methylphenol, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis (4-ethyl-6) -Tert-butylphenol), 1,3,5-tris- (3 ', 5'-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid, 1,1,3-tris- (2-methyl-4- Hydroxy-5-tert-butylphenyl) butane, 4,4-butylidene-bis- (3-methyl-6-t rt-butylphenol), n-octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate, tetrakis- (methylene-3- (3 ′, 5′-di-tert-) Butyl-4′-hydroxyphenyl) propionate) methane, tri-ethylene glycol-bis-3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate, 3,9-bis [1,1-dimethyl -2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3, 5-trimethyl-2,4,6-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, di (α-methyl) Benzyl) phenol, N, N′-bis-3- (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionylhexamethylenediamine, 1,3,5-trimethyl-2,4,6- And tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzene.

Examples of the paraphenylenediamines include N-isopropyl-N′-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, and N- (1- Methylheptyl) -N′-p-phenylenediamine, N, N′-di-2-naphthyl-p-phenylenediamine, and the like.
Examples of the amine compound include phenothiazine, N-phenyl-2-naphthylamine, 1-naphthylamine, N, N′-diphenyl-4-phenylenediamine, N, N′-di-butyl-4-phenylenediamine, and the like. Can be mentioned.
Examples of the copper dialkyldithiocarbamate include copper dibutyldithiocarbamate, copper diethyldithiocarbamate, copper dimethyldithiocarbamate, and the like.

Examples of the N-oxyl compound include 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and 4-acetylamino. -2,2,6,6-tetramethylpiperidine-1-oxyl, 1-oxyl-2,2,6,6-tetramethyl-4- (2,3-dihydroxypropoxy) piperidine, 1-oxyl-2, 2,6,6-tetramethyl-4-glycidyloxypiperidine, bis- (2,2,6,6-tetramethylpiperidine-1-oxyl) sebacate, bis (2,2,6,6-tetramethyl-N -Oxyl piperidyl) succinate, bis (2,2,6,6-tetramethylpiperidinoxy) sebacate and the like.
The decomposition product is not particularly limited as long as it is a decomposition product of an alkylphenol compound, a paraphenylenediamine, an amine compound, a dialkyldithiocarbamate copper salt, and an N-oxyl compound.

Next, the process (purification process) which refine | purifies glycidyl acrylate using a nitroso compound and the radical polymerization inhibitor different from a nitroso compound is demonstrated.
The purification step is characterized in that a nitroso compound and a radical polymerization inhibitor different from the nitroso compound are used in combination. Thereby, radical polymerization of glycidyl acrylate in the gas phase part is sufficiently suppressed, generation of a polymer due to ring opening of the epoxy site is also suppressed, and stable continuous operation for a long time can be achieved.

The method for producing glycidyl acrylate of the present invention prevents polymerization that occurs in a purification tower when purifying glycidyl acrylate. Accordingly, as a purification tower, regardless of its name, it includes a wide range of equipment used in the production process of glycidyl acrylate and used for the purpose of purifying and / or producing glycidyl acrylate, and includes a distillation tower, a rectifying tower, and a stripping tower. , An azeotropic separation tower, a dehydration tower, an acetic acid separation tower, a light boiling substances separation tower, a high boiling substances separation tower, and the like.
In the present invention, it is preferable to use a rectifying column as a purification column.

In the present specification, “rectification” means distillation in which the separation area is efficiently improved by increasing the contact area of gas and liquid.
Further, in the present specification, to “use” a nitroso compound and a radical polymerization inhibitor different from the nitroso compound, these compounds are used as they are, and the nitroso compound and a radical polymerization inhibitor different from the nitroso compound are used. Not only the form but also the form used after changing to another compound derived from these compounds is included.

As a preferable form of the said refinement | purification process, the following forms etc. are mentioned, for example, What combined these 2 or more is more preferable.
(1) The nitroso compound is a nitrosophenyl compound or a nitrosamine compound.
(2) The radical polymerization inhibitor is an alkylphenol compound.
(3) The nitroso compound decomposition gas is introduced into the rectification column to perform rectification.

First, (I) a form using a nitroso compound and (II) a form using a radical polymerization inhibitor different from the nitroso compound will be described.

(I) As a form using a nitroso compound, the form which introduce | transduces the decomposition gas of a nitroso compound into a rectification column, and performs rectification is preferable.
The decomposition gas for the nitroso compound is not particularly limited as long as it is a gas obtained by decomposing the nitroso compound. The cracked gas has a polymerization inhibiting action.
In addition, when a nitroso compound is used as a gas (gas), a small amount of the nitroso compound can be stably supplied into the rectifying column as compared with liquid or solid, and the supply amount of the nitroso compound can be easily adjusted. .
Furthermore, when the cracked gas is supplied to the bottom of the rectifying tower, the cracked gas component can be easily mixed with the glycidyl acrylate present in the gaseous state while rising in the rectifying tower, and thereby more effective. In particular, the polymerization of these compounds can be prevented.

Examples of the method for generating the decomposition gas of the nitroso compound include a method in which a solution obtained by dissolving a nitroso compound in a solvent is added to a decomposition tank, and the nitroso compound solution is heated to generate the decomposition gas.

The solvent used for dissolving the nitroso compound may be appropriately selected depending on the conditions in the rectification column and the chemical and physical properties such as solubility and decomposability of the nitroso compound in the solvent.
Examples of the solvent include water, alcohol, hydrocarbon, ether, ketone, ester, and the like. These can be used alone or in combination of two or more.
Examples of the alcohol include butyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether and the like.
Examples of the hydrocarbon include hexane, heptane, nonane, decane, undecane, dodecane, tridecane, and tetradecane.
Examples of the ether include polyethylene glycol, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, and triethylene glycol dimethyl ether.
Examples of the ketone include methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, benzyl phenyl ketone, cyclohexyl phenyl ketone and the like.
Examples of the ester include ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and ethyl lactate.

From the viewpoint of the temperature at which the nitroso compound is sufficiently thermally decomposed, the heating temperature when generating the cracked gas (heating temperature in the decomposition tank) is preferably 20 ° C or higher, more preferably 30 ° C or higher, and 40 ° C or higher. Further preferred. There is no need for heating above the thermal decomposition temperature of the nitroso compound.
The pressure for generating the cracked gas (pressure in the decomposition tank) is preferably 0.01 hPa or more, more preferably 0.1 hPa or more, and further preferably 1 hPa or more. Moreover, 200 hPa or less is preferable, 150 hPa or less is more preferable, and 100 hPa or less is still more preferable.

The method for charging the nitroso compound is not particularly limited, and it may be charged into the decomposition tank before rectification, may be charged at the start of rectification, or may be charged during the rectification. Moreover, it may charge or throw in collectively, may be thrown in intermittently, and may be dripped continuously and thrown in.
In the decomposition tank for generating the decomposition gas, it is preferable to stir in order to make the nitroso compound uniform in the system.

The decomposition gas of the nitroso compound generated as described above can be introduced into the rectification tower by, for example, connecting the decomposition tank to the rectification tower.
The structure of the rectification column is not particularly limited as long as rectification can be performed, but a plate type rectification column or a packed rectification column having a large gas-liquid contact area is preferable. Examples of the shelf include a sheave tray, a bubble cap tray, a valve tray, an angle tray, a flexi tray, a ballast tray, and a chimney tray. Examples of the filler include sulzer packing, Dixon packing, Raschig ring, Lessing ring, pole ring, and saddle.
Moreover, in order to connect the said decomposition tank and rectification tower, a connecting pipe etc. can be used. The shape and material of the connection pipe are not particularly limited, but may be any corrosion resistance to glycidyl acrylate, and SUS304, SUS304L, SUS316, SUS316L, SUS317, SUS317L stainless steels, hastelloys, and the like are preferable.

The pressure in the rectification column is preferably 0.01 hPa or more, more preferably 0.1 hPa or more, and still more preferably 1 hPa or more. Moreover, 200 hPa or less is preferable, 150 hPa or less is more preferable, and 100 hPa or less is still more preferable. In addition, since the said decomposition tank and the rectification tower are connected normally, the pressure in the said decomposition tank and the pressure in a rectification tower become the same in that case.
The temperature in the rectification column is not particularly limited because it depends on the pressure in the rectification column, but is preferably 130 ° C. or less, more preferably 110 ° C. or less, from the viewpoint of preventing polymerization of glycidyl acrylate in the rectification column. 100 ° C. or lower is more preferable. Further, the lower limit is not a problem as long as the temperature enables rectification, and is preferably 35 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 50 ° C. or higher.

The total amount of the nitroso compound and the decomposition product thereof is preferably 0.01 mass ppm or more, more preferably 0.1 mass ppm or more as a lower limit with respect to the rising vapor amount of glycidyl acrylate. Yes, and more preferably 0.5 ppm by mass or more. The upper limit is preferably 5000 ppm by mass or less, more preferably 1000 ppm by mass or less, and still more preferably 500 ppm by mass or less.
The amount of rising steam here means the total amount of monomer vapor generated in the reboiler according to the amount of heat applied to the reboiler of the rectification column.

A more preferred form is a form in which the decomposition gas of the nitroso compound is introduced into the rectification column together with the non-condensable gas. By using a non-condensable gas in combination, the amount of the nitroso compound decomposition gas introduced can be easily controlled. In other words, the amount of nitroso compound decomposition gas generated varies depending on the amount of nitroso compound charged into the decomposition tank, the amount of solvent, the cross-sectional area of the container, the decomposition tank temperature, the stirring speed, etc. By controlling, the introduction amount of the decomposition gas of the nitroso compound into the rectification column can be easily controlled.

The non-condensable gas means a gas having a dew point equal to or lower than the temperature in the rectification column, for example, rare gases such as air, oxygen, nitrogen, helium, and argon; a mixture thereof; exhaust gas generated in the manufacturing process, etc. Is mentioned. Nitrogen, helium and the like are preferable.
The non-condensable gas preferably contains oxygen.
When oxygen is included as the non-condensable gas, the oxygen concentration in the non-condensable gas is preferably in the range of 0.01 to 9% by volume. If the oxygen concentration in the non-condensable gas is less than 0.01% by volume, there is a risk that glycidyl acrylate may cause polymerization, and if the oxygen concentration exceeds 9% by volume, it may belong to the explosion range. .
In the non-condensable gas for introducing the nitroso compound into the rectification column, oxygen is not necessarily required because the purpose is to introduce a decomposition gas of the nitroso compound. On the other hand, as described later, in the non-condensable gas introduced into the liquid phase portion at the bottom of the rectifying column, it is particularly preferable to contain oxygen in order to more effectively obtain the effect of the radical polymerization inhibitor.

The amount of the non-condensable gas introduced into the rectification column may be 10 vol% / h or more with respect to the capacity of the decomposition tank from the viewpoint of efficiently introducing the cracked gas having a polymerization-inhibiting action into the rectification column. Preferably, 50 vol% / h or more is more preferable, and 100 vol% / h or more is still more preferable. Moreover, since the loss of a nitroso compound will increase when there is too much introduction amount of non-condensable gas, 3000 vol% / h or less is preferable and 2000 vol% / h or less is more preferable.

Examples of the method for introducing the decomposition gas of the nitroso compound together with the non-condensable gas into the rectification column include the following methods. An introduction pipe for introducing a non-condensable gas is attached to a decomposition tank that generates a decomposition gas for a nitroso compound, so that a decomposition gas for the nitroso compound generated in the decomposition tank and a non-condensable gas introduced to the decomposition tank are Both are introduced into the rectification column through the connecting pipe.

In a more preferred form, the decomposition gas of the nitroso compound is introduced together with the non-condensable gas into the gas phase part at the bottom of the rectification column. By introducing the decomposition gas of the nitroso compound into the gas phase part at the bottom of the rectifying column, the polymerization of glycidyl acrylate in the gas phase part is suppressed more effectively, and the formation of epoxy ring-opened products is suppressed. be able to.
Moreover, it is particularly preferable to introduce a non-condensable gas further containing oxygen into the liquid phase portion at the bottom of the rectifying column. A non-condensable gas containing oxygen is attached to the rectifying column so as to reach the liquid phase portion at the bottom of the column, so that the non-condensable gas containing oxygen is introduced into the liquid phase at the bottom of the rectifying column. A condensable gas can be introduced.
Note that glycidyl acrylate is mainly contained in the liquid phase portion at the bottom of the rectifying column.
The phrase “mainly containing glycidyl acrylate” means that 50% by mass or more of glycidyl acrylate is contained when the liquid phase part at the bottom of the column is 100% by mass. Preferably it is 60 mass% or more, More preferably, it is 70 mass% or more.

(II) As a form using a radical polymerization inhibitor different from the nitroso compound, a form in which the radical polymerization inhibitor is introduced from the top of the rectifying column is preferable.
By introducing the radical polymerization inhibitor from the top of the rectifying column, mixing with glycidyl acrylate is easy, and the purification operation can be continued without changing the composition in the rectifying column.

When introducing a radical polymerization inhibitor from the top of the rectifying column, the radical polymerization inhibitor (regardless of solid or liquid form) is similar to the liquid composition of the rectification system and is easily dissolved. It is preferable to use it dissolved in acrylate.
Further, the radical polymerization inhibitor dissolved in glycidyl acrylate can be introduced from the top of the rectification column using, for example, a pump.
In the case where the radical polymerization inhibitor used in the present invention is a liquid itself, even if the composition in the tower and the mutual solubility are not sufficient, the viscosity or If there is no hindrance in terms of reactivity, the supply from the top of the column is possible.
The radical polymerization inhibitor can be used alone or in combination of two or more. Further, the supply timing is not particularly limited, and all may be supplied at the same time, or the supply timing may be shifted for each type of radical polymerization inhibitor.

The addition amount (addition amount from the top of the column) of the radical polymerization inhibitor different from the nitroso compound is appropriately adjusted according to the operating conditions and is not particularly limited. From the viewpoint of preventing polymerization of glycidyl acrylate, the total amount of the radical polymerization inhibitor is preferably 3 mass ppm or more, more preferably 300 mass ppm or more as a lower limit with respect to the rising vapor amount of glycidyl acrylate, More preferably, it is 500 mass ppm or more. The upper limit is preferably 10,000 ppm by mass or less, more preferably 6000 ppm by mass or less, and still more preferably 4000 ppm by mass or less.
The meaning of the rising steam amount is as described above. The total amount of monomer vapor can be easily calculated by calculation, and is a number that is an important factor in determining the input standard of the radical polymerization inhibitor.

As a more preferable form, a radical polymerization inhibitor is added to the liquid phase part at the bottom of the column containing the glycidyl acrylate solution.
The addition amount of the radical polymerization inhibitor to the liquid phase part at the bottom of the column is preferably 10 to 10000 ppm by mass, more preferably 100 to 5000 ppm by mass when the liquid phase at the bottom is 100% by mass. Yes, more preferably 500 to 2000 ppm by mass.
Thereby, the effect | action which prevents superposition | polymerization of glycidyl acrylate is exhibited more effectively.
When the radical polymerization inhibitor is also added to the liquid phase part at the bottom of the column, in (I) above, it is more preferable to introduce a non-condensable gas containing oxygen into the liquid phase at the bottom of the column.
The radical polymerization inhibitor exhibits its effectiveness more effectively due to the presence of oxygen molecules. By introducing a non-condensable gas containing oxygen into the liquid phase part at the bottom of the rectifying column, polymerization of glycidyl acrylate in the liquid phase part is suppressed. Further, molecular oxygen that has not been trapped in the liquid phase part is mixed with glycidyl acrylate and a radical polymerization inhibitor in the gas phase part, thereby suppressing polymerization of glycidyl acrylate in the gas phase part.

The purification step in the present invention purifies glycidyl acrylate using a nitroso compound and a radical polymerization inhibitor different from the nitroso compound. Therefore, in the said refinement | purification process, the form using the radical polymerization inhibitor different from said (I) nitroso compound and (II) nitroso compound can be refine | purified combining suitably.

As a particularly preferred form of the purification step, a decomposition gas of the nitroso compound is introduced into the gas phase portion of the bottom of the rectification tower together with a non-condensable gas, and a radical polymerization inhibitor different from the nitroso compound is used. It is the form introduced from the tower top of the rectification tower.
If a large amount of nitroso compound is introduced as a liquid, the nitroso compound will be mixed into the distillate and cause coloration. By using a decomposition gas of the nitroso compound, only the minimum amount necessary to prevent polymerization of glycidyl acrylate is introduced. Coloring is suppressed as compared with the case where a liquid is introduced. Moreover, by using together with the said radical polymerization inhibitor, the introduction amount of a nitroso compound can be suppressed to the minimum, and coloring can further be suppressed.

As the most preferable form of the above purification step, a decomposition gas of N-nitrosophenylhydroxylamine salt is introduced into a gas phase part of the bottom of a glycidyl acrylate rectification column together with a non-condensable gas, and an alkylphenol compound Is introduced from the top of the rectification column.
In addition to this, as described above, it is more preferable to further combine the introduction of a non-condensable gas containing oxygen and the addition of a radical polymerization inhibitor into the liquid phase portion at the bottom of the rectifying column.

In each of the above embodiments, the tower top temperature depends on the pressure in the rectification tower, and the lower the pressure, the lower the tower top temperature. From the viewpoint of preventing polymerization, the lower the temperature, the more difficult the polymerization proceeds and the safe operation is possible. Also, the liquid phase temperature at the bottom of the column is the pressure in the rectifying column and the liquid composition at that time (as the rectification proceeds, the light boiling product is distilled off and the high boiling point is left at the bottom of the column. The temperature gradually increases). Furthermore, the gas phase temperature at the bottom of the column depends on the pressure in the rectification column. Thus, the tower top temperature, the gas phase temperature and the liquid phase temperature at the bottom of the tower are determined by the pressure in the rectification tower.

FIG. 1 shows an example of the purification process in the present invention.
In the decomposition tank 2, while introducing the non-condensable gas from the non-condensable gas introduction pipe 3, the nitroso compound solution 4 is heated to generate the decomposition gas. The generated cracked gas is introduced into the tower bottom gas phase section 6 of the rectification tower 1 through the connecting pipe 5 together with the non-condensable gas. Further, a non-condensable gas is introduced from the non-condensable gas introduction pipe 3 into the tower bottom liquid phase part 7, and a radical polymerization inhibitor is further added from the tower top part 8.

The manufacturing method of the glycidyl acrylate of this invention is characterized by including the refinement | purification process of the said glycidyl acrylate.

The glycidyl acrylate can be produced by reacting acrylic acid or a metal salt of acrylic acid with epichlorohydrin.
Examples of the metal salt of acrylic acid include alkali metal salts (sodium, potassium, lithium salts, etc.) and alkaline earth metal salts (calcium, magnesium salts, etc.). These may be used alone or in combination of two or more.

The glycidyl acrylate can be synthesized from acrylic acid or a metal salt of acrylic acid. Here, the case where the metal salt of acrylic acid is used as an example of the manufacturing method of glycidyl acrylate is demonstrated below.
In the reaction using a metal salt of acrylic acid, the amount of epichlorohydrin used is preferably 1 to 15 mol per 1 mol of the metal salt of acrylic acid. By setting within this range, the reaction can be efficiently carried out, and the target glycidyl acrylate can be synthesized in a high yield. More preferably, it is 2-11 mol, More preferably, it is 3-9 mol.

The reaction time is not particularly limited, but if the reaction time is too short, the reaction may not proceed and a sufficient yield may not be obtained. If the reaction time is too long, the produced glycidyl acrylate may be decomposed. In such a case, a sufficient yield may not be obtained, so that it is preferably 0.1 to 10 hours, more preferably 1 to 9 hours, and further preferably 2 to 7 hours.
The reaction temperature is not particularly limited, but if the reaction temperature is too high, the produced glycidyl acrylate may be decomposed or polymerized. If the reaction temperature is too low, the reaction does not proceed. More preferably, it is 40-110 degreeC, More preferably, it is 50-100 degreeC.

In the above reaction, a basic catalyst can be used. The basic catalyst is preferably an epoxy compound such as epichlorohydrin that does not cause ring opening or polymerization. Examples of organic bases that are basic catalysts include trimethylamine, triethylamine, tributylamine, triethanolamine, dimethylethanolamine, diethylethanolamine, and other amines; tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropyl Quaternary ammonium salts such as ammonium hydroxide, tetramethylammonium chloride, trimethylethylammonium chloride, dimethyldiethylammonium chloride, methyltriethylammonium chloride, tetraethylammonium chloride, trimethylbenzylammonium chloride, triethylbenzylammonium chloride, and the like can be mentioned. These basic catalysts may be used independently and may use 2 or more types together.

Among the above basic catalysts, quaternary ammonium salts are preferable, and specifically, tetramethylammonium chloride, trimethylethylammonium chloride, dimethyldiethylammonium chloride, methyltriethylammonium chloride, tetraethylammonium chloride, trimethylbenzylammonium chloride, triethyl. Preferred examples include benzylammonium chloride. More preferably, tetramethylammonium chloride, tetraethylammonium chloride, trimethylbenzylammonium chloride, triethylbenzylammonium chloride and the like can be mentioned. A quaternary ammonium salt may be used independently and may be used in combination of arbitrary 2 or more types.

The amount of the basic catalyst used is preferably 0.0001 parts by mass or more, more preferably 0, relative to 100 parts by mass of the total amount of the metal salt of acrylic acid and epichlorohydrin as the reaction raw materials. 0.002 part by mass or more. Moreover, an upper limit becomes like this. Preferably it is 1 mass part or less, More preferably, it is 0.5 mass part or less.

By subjecting the glycidyl acrylate obtained as described above to the purification step, production of a polymer and an epoxy ring-opened product is suppressed, and glycidyl acrylate can be produced stably for a long time.

In addition, before attaching | subjecting the obtained glycidyl acrylate to the said refinement | purification process, it is preferable to attach | subject to a solid-liquid separation process and a water washing process.
The solid-liquid separation step is not particularly limited as long as the solid portion and the liquid portion made of a metal chloride salt produced by the synthesis of glycidyl acrylate can be separated, and filtration, centrifugation, decantation, etc. may be used. it can. As the solid-liquid separation method, filtration is preferable among these because of the ease of separation efficiency and operability.
When the solid-liquid separation is performed by filtration, it may be performed under any conditions of pressurization, normal pressure, and reduced pressure, but pressurization or normal pressure is preferable.

The water washing step is performed for the purpose of removing the catalyst. The amount of water used for washing is preferably 3 to 50% by mass, more preferably 5 to 35% by mass, and even more preferably 7 to 25% by mass with respect to 100% by mass of the total liquid amount after the solid-liquid separation step. is there.
Moreover, 0-50 degreeC is preferable, as for the water temperature used for water washing, More preferably, it is 5-40 degreeC, More preferably, it is 10-35 degreeC. By using water at such a temperature, the by-product glycidol can be efficiently dissolved in the aqueous layer, and dissolution of glycidyl acrylate in the aqueous layer can be suppressed.

More preferably, oil-water separation is performed after the water washing step, whereby an oil layer containing glycidyl acrylate can be obtained.
Moreover, when many reaction raw materials and by-products are contained in the obtained oil layer, it is more preferable to perform simple distillation before the purification step to increase the concentration of glycidyl acrylate in the oil layer.

The present invention is also a glycidyl acrylate composition in which a nitroso compound and / or a decomposition product of the nitroso compound and a radical polymerization inhibitor different from the nitroso compound coexist in glycidyl acrylate.
As described above, the combined use of a nitroso compound and a radical polymerization inhibitor different from the nitroso compound effectively suppresses the progress of radical polymerization of glycidyl acrylate and cationic polymerization due to ring opening of the epoxy moiety. Is not exhibited only at the time of purification of glycidyl acrylate, and by making these into glycidyl acrylate, the polymerization of glycidyl acrylate can be suppressed and kept stable.
Here, the decomposition product of the nitroso compound is the same substance as the decomposition gas of the nitroso compound, and may be present in the state of gas as in the purification step of the method for producing glycidyl acrylate of the present invention. It may exist in a solid state.

The glycidyl acrylate composition of the present invention may contain a nitroso compound or a decomposition product of the nitroso compound.
When a nitroso compound is included, the content of the nitroso compound is preferably 0.00001 to 3% by mass with respect to 100% by mass of glycidyl acrylate in the glycidyl acrylate composition. More preferably, it is 0.0001-1 mass%, More preferably, it is 0.0005-0.1 mass%.
When the decomposition product of the nitroso compound is included, the N content of the decomposition product is preferably 0.01 to 1000 mass ppm with respect to the glycidyl acrylate of the glycidyl acrylate composition. More preferably, it is 0.05-500 mass ppm, More preferably, it is 0.1-100 mass ppm.
The N content can be measured using a trace total nitrogen analyzer TN-100 manufactured by Mitsubishi Chemical Analytech.

It is preferable that content of the radical polymerization inhibitor in the glycidyl acrylate composition of this invention is 0.0001-3 mass% with respect to 100 mass% of glycidyl acrylates in a composition. More preferably, it is 0.001-1 mass%, More preferably, it is 0.002-0.1 mass%.
The glycidyl acrylate composition contains a nitroso compound and / or a decomposition product of the nitroso compound and a radical polymerization inhibitor different from the nitroso compound in the above-mentioned preferable ratio, thereby suppressing the polymerization of the glycidyl acrylate and keeping it stable. More fully demonstrated.

The glycidyl acrylate content in the glycidyl acrylate composition of the present invention is preferably 90% by mass or more with respect to 100% by mass of the glycidyl acrylate composition. More preferably, it is 95 mass% or more, More preferably, it is 98 mass% or more. Even when the glycidyl acrylate composition of the present invention contains glycidyl acrylate at a high concentration, the glycidyl acrylate composition of the present invention contains a high concentration of glycidyl acrylate because it can exhibit an excellent polymerization inhibition effect of glycidyl acrylate. This is a preferred embodiment of the product.

The glycidyl acrylate composition of the present invention may contain other components other than glycidyl acrylate, a nitroso compound and / or a decomposition product of the nitroso compound, and a radical polymerization inhibitor different from the nitroso compound, but may contain other components. The amount is preferably 10% by mass or less with respect to 100% by mass of the glycidyl acrylate composition. More preferably, it is 5 mass% or less, More preferably, it is 2 mass% or less.

The glycidyl acrylate contained in the glycidyl acrylate composition of the present invention may be obtained by the above-described method for producing glycidyl acrylate of the present invention, or may be obtained by a different production method. Preferably, the glycidyl acrylate composition of the present invention is a glycidyl acrylate obtained by the method for producing glycidyl acrylate of the present invention, and if necessary, a nitroso compound, a decomposition gas of the nitroso compound, a radical polymerization inhibitor different from the nitroso compound. It is that it was prepared by adding.
As described above, the glycidyl acrylate composition of the present invention is prepared by using the glycidyl acrylate obtained by the method for producing glycidyl acrylate of the present invention. One of the forms.

The method for producing glycidyl acrylate according to the present invention has the above-described configuration, sufficiently suppresses radical polymerization of glycidyl acrylate in the gas phase portion, suppresses generation of a polymer due to ring opening of the epoxy site, and is stable for a long time. It is an excellent manufacturing method that allows continuous operation.

It is a figure which shows an example of the refinement | purification process in this invention.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and appropriate modifications are made within a range that can meet the purpose described above and below. Any of these can be carried out and are included in the technical scope of the present invention.
Unless otherwise specified, “%” and “ppm” represent “mass%” and “mass ppm”, and “part” represents “part by mass”.

Synthesis Example (1) Preparation of Glycidyl Acrylate (GA) Synthesis Liquid Into a 5 L reaction vessel equipped with a gas introduction tube, a thermometer, a stirrer, and a reflux condenser, 900 g of potassium acrylate (manufactured by Nippon Shokubai Co., Ltd.), epichloro Hydrin (EpCH) (manufactured by Daiso Corporation) 3780 g, Adekastab AO-20 (1,3,5-tris- (3 ′, 5′-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid) (manufactured by ADEKA) 9.4 g, and 9.4 g of 2,6-di-tert-butyl-4-methylphenol (BHT) (manufactured by Kyodo Yakuhin Co., Ltd.), bis (2,2,6,6-tetramethylpiperidi) sebacate Noxy) (EC3314A) (manufactured by Nalco Co.) was charged in an amount of 9.4 g, the water content in the system was measured by the Karl Fischer method, and water was added to adjust the water content in the system to 500 ppm.
Thereafter, 6.7 g of tetramethylammonium chloride (manufactured by Nippon Special Chemical Co., Ltd.) was added and reacted at 70 ° C. for 4 hours while blowing 7% oxygen gas (93% nitrogen gas). After completion of the reaction, the salt produced by the reaction was removed by filtration to obtain a filtrate. 10 mass% of water was added with respect to the obtained filtrate amount, it stirred for 30 minutes, oil-water separation was performed after standing and the oil layer was obtained.
The amount of the GA synthesis solution thus obtained was 3812 g, and the composition was 73.0% by mass for EpCH, 0.03% by mass for glycidol (GDO), and 21.3% by mass for GA. Moreover, the yield of GA with respect to 900 g of potassium acrylate used was 77.5 mol%.
(2) Crude GA bottom liquid 3789 g of this GA synthesis liquid was charged into a 5 L single distillation apparatus equipped with a gas introduction tube, a thermometer, and a constant pressure reduction device, and 7% oxygen gas (93% nitrogen gas) was blown in Was gradually reduced from 67 hPa to 40 hPa, and EpCH was distilled off by simple distillation until the bottom temperature reached 70 ° C. to obtain 960 g of a crude GA bottom solution.
The crude GA bottom liquid composition thus obtained had EpCH of 11.4 mass%, GDO of 0.4 mass%, and GA of 75.1 mass%.

Example 1
904 g of the crude GA bottom liquid obtained in the synthesis example was added to a polymerization inhibitor introduction pipe at the top of the tower, a connection pipe with a decomposition tank at the gas phase at the bottom of the tower, and 7% oxygen gas (93% in the liquid phase at the bottom of the tower). Nitrogen gas) was charged into a rectification apparatus (rectification tower) equipped with an introduction pipe, and rectification was performed at a reduced pressure of 20 hPa.
As a radical polymerization inhibitor introduced from the top of the column, a part of the distillate in which 2,000 ppm of BHT was dissolved was introduced with respect to the amount of ascending steam. Further, NPH was previously gasified in an N-nitrosophenylhydroxylamine ammonium salt (NPH) decomposition tank, and the decomposition tank was connected to a rectifying apparatus. And this NPH gas was introduce | transduced with the non-condensable gas into the gaseous-phase part of the tower bottom part through the connection pipe.
After the rectification, it was confirmed whether or not a polymer was formed in the packing (sulzer packing) and the gas phase, and no polymer was confirmed.

Example 2
Even when Example 1 was repeated 15 times, no polymer was formed in the packing and gas phase.

Example 3
When Example 1 was repeated 28 times, a very small amount of polymer was formed in the packing. When ¹³ C-NMR of the obtained polymer was measured, a peak characteristic of a homopolymer of glycidyl acrylate was confirmed around 177 PPM, 67 PPM, 51 PPM, and 43 PPM.

Comparative Example 1
A rectification operation was performed using the apparatus used in Example 1. However, when NPH gas was not introduced into the gas phase portion at the bottom of the column, a polymer was formed in the packing and the gas phase portion after rectification. When ¹³ C-NMR of the obtained polymer was measured, in addition to the vicinity of 177 PPM, 67 PPM, 51 PPM, and 43 PPM, a peak derived from the acryloyl group was confirmed in the vicinity of 130 PPM, and a part of the ring-opening polymer of the epoxy moiety was mixed. It was suggested that

Comparative Example 2
A rectification operation was performed using the apparatus used in Example 1. However, when the polymerization inhibitor was not introduced into the gas phase portion at the top of the column, a polymer was formed in the packing and the gas phase portion after rectification. When ¹³ C-NMR of the obtained polymer was measured, in addition to the vicinity of 177 PPM, 67 PPM, 51 PPM, and 43 PPM, a peak derived from the acryloyl group was confirmed in the vicinity of 130 PPM, and a part of the ring-opening polymer of the epoxy moiety was mixed. It was suggested that

In Table 1, ◯ marks in alkylphenol and NPH indicate that these components were added. In the polymer, ◯: indicates that no polymer was produced, Δ: indicates that a very small amount of polymer was produced, and x: indicates that a large amount of polymer was produced.

Example 4
960 g of the crude GA bottom liquid obtained in the synthesis example was added to a polymerization inhibitor introduction pipe at the top of the tower, a connection pipe with a decomposition tank at the gas phase at the bottom of the tower, and 7% oxygen gas (93% in the liquid phase at the bottom of the tower). Nitrogen gas) was charged into a rectification apparatus (rectification tower) equipped with an introduction pipe and subjected to multistage distillation.
The operating conditions of the decomposition tank were as follows: 0.02 g of N-nitrosophenylhydroxylamine ammonium salt was dissolved in 10 g of polyethylene glycol, and 7% oxygen gas (93% nitrogen gas) was introduced at 500 vol% / h, while 22 hpa, The gas decomposed at a liquid temperature of 70 ° C. was introduced into the gas phase portion at the bottom of the rectifying column. By these operations, 95.9 g of light boiling liquid (GA content 17.5 wt%), 140.7 g of initial fraction (GA content 85.9 wt%), 534.4 g of glycidyl acrylate (GA purity 99.8 wt%) Got. When the N content concentration in the obtained distillate was measured with a trace total nitrogen analyzer TN-100 type manufactured by Mitsubishi Chemical Analytech, all were 1 ppm.
Multistage distillation was performed under the following pressure and temperature conditions. The theoretical number of distillation columns used for multistage distillation was 10.
Light boiling cut: Distilled to a tower top pressure of 40 hPa and a tower top temperature of 70 ° C.
Initial distillation cut: The pressure at the top of the tower was reduced from 40 hPa to 20 hPa, and the top temperature was distilled to 79.5 ° C.
Main distillation: Lower column pressure: 22 hPa, GA is distilled to a lower column temperature of 110 ° C.
As a result of adding 10 mg of BHT to 100 g of the obtained distillate and storing it in a constant temperature dryer at 50 ° C. for 90 days, no high molecular weight product was produced.

Example 5
The same radical polymerization inhibitor as that in Example 4 was used except that 10 mg of tert-butylhydroquinone (TBH) was added instead of BHT.

Example 6
Example 4 except that 10 mg of Antage W400 (2,2′-methylene-bis (4-methyl-6-tert-butylphenol), manufactured by Kawaguchi Chemical Industry Co., Ltd.) was added instead of BHT as the added radical polymerization inhibitor. As well as.

Example 7
Example 4 except that 10 mg of Antage W500 (2,2′-methylene-bis (4-ethyl-6-tert-butylphenol), manufactured by Kawaguchi Chemical Industry Co., Ltd.) was added instead of BHT as the added radical polymerization inhibitor. As well as.

Comparative Example 3
As a result of storing 100 g of the main distillate obtained in Example 4 in a constant temperature dryer at 50 ° C. for 2 days, production of a high molecular weight product was confirmed.

Table 2 summarizes the results of Examples 4 to 7 and Comparative Example 3.

Example 8
As a result of adding 10 mg of BHT and 0.5 mg of NPH to 100 g of the distillate obtained in Comparative Example 1 and storing it in a constant temperature dryer at 50 ° C. for 50 days, no high molecular weight product was produced.

Example 9
The same procedure as in Example 8 was performed except that 10 mg of TBH was added instead of BHT as the added radical polymerization inhibitor.

Example 10
The same radical polymerization inhibitor as in Example 8 was used except that 10 mg of ANTAGE W400 was added instead of BHT.

Example 11
The same radical polymerization inhibitor as in Example 8 was used except that 10 mg of ANTAGE W500 was added instead of BHT.

Table 3 summarizes the results of Examples 8-11.

Thus, by using the method for producing glycidyl acrylate, which includes the step of purifying glycidyl acrylate using a nitroso compound and a radical polymerization inhibitor different from the nitroso compound, glycidyl in the gas phase portion is used. Sufficient suppression of radical polymerization of acrylate, suppression of the formation of polymer by ring opening of epoxy site, and the mechanism of action that enables stable continuous operation for a long time, and decomposition of nitroso compound or nitroso compound into glycidyl acrylate By coexisting a gas and a radical polymerization inhibitor that is different from the nitroso compound, radical polymerization of glycidyl acrylate is sufficiently suppressed, formation of a polymer due to ring opening of the epoxy moiety is also suppressed, and glycidyl acrylate is kept stable. The mechanism of action It is the same.
Therefore, it can be said from the results of the above-described embodiments that the present invention can be applied in the entire technical scope of the present invention and in various forms disclosed in the present specification, and can exhibit advantageous effects.

1: rectification tower 2: decomposition tank 3: non-condensable gas introduction pipe 4: nitroso compound solution 5: connection pipe 6: tower bottom gas phase section 7: tower bottom liquid phase section 8: tower top

Claims (5)

A method for producing glycidyl acrylate, comprising:
The method for producing glycidyl acrylate includes a step of purifying glycidyl acrylate using a nitroso compound and a radical polymerization inhibitor different from the nitroso compound. The method for producing glycidyl acrylate according to claim 1, wherein the nitroso compound is a nitrosophenyl compound or a nitrosamine compound. The method for producing glycidyl acrylate according to claim 1 or 2, wherein the radical polymerization inhibitor is an alkylphenol compound. The method for producing glycidyl acrylate according to any one of claims 1 to 3, wherein the purification step includes a step of performing rectification by introducing a decomposition gas of a nitroso compound into a rectification column. A glycidyl acrylate composition comprising glycidyl acrylate and a nitroso compound and / or a decomposition product of the nitroso compound, and a radical polymerization inhibitor different from the nitroso compound.

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