Method for producing (METH)acrylic acid ester having vinyl ether group

Abstract

To provide a method for efficiently preventing polymerization in the liquid phase in producing a (meth)acrylic acid ester having a vinyl ether group by ester exchange reaction.SOLUTION: There is provided a method for producing a (meth)acrylic acid ester having a vinyl ether group, which comprises a step of obtaining a (meth)acrylic acid ester having a vinyl ether group by ester exchange reaction by using a raw material solution containing a raw material (meth)acrylic acid ester, a vinyl ether compound containing a hydroxyl group, and a catalyst, wherein the raw material solution further contains a predetermined phenol-based antioxidant and a phosphite ester, the mass ratio of the predetermined phenol-based antioxidant in the raw material solution is 0.2 mass% or more and the mass ratio of the phosphite ester is 0.2 mass% or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a (meth)acrylic acid ester having a vinyl ether group. More specifically, the present invention relates to a method for producing a (meth)acrylic acid ester having a vinyl ether group that is used as a raw material for various industrial products. [Background technology]

[0002] (Meth)acrylic acid esters having a vinyl ether group have a (meth)acryloyl group containing a radically polymerizable double bond, and are easily polymerizable compounds that can be easily polymerized by heat, light, ultraviolet light, etc., and are therefore very useful as monomers for polymers, and various methods for producing them have been investigated. As one of the reaction processes, a process for producing a (meth)acrylic acid ester having a vinyl ether group by subjecting a raw material (meth)acrylic acid ester and a hydroxyl group-containing vinyl ether compound to an ester exchange reaction is known. In this reaction process, since both the raw material and the target product are easily polymerizable compounds, various methods for preventing their polymerization have been investigated.

[0003] For example, a method for producing a (meth)acrylic ester having an ether group from a reaction raw material containing a (meth)acrylic ester and a hydroxyl group-containing ether compound has been disclosed, the method comprising the step of reacting the reaction raw material in the presence of a specific N-nitrosophenylhydroxylamine salt, a phosphite ester and / or a thioether, and a primary antioxidant (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-197236 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a (meth)acrylic acid ester having a vinyl ether group is produced in the presence of a catalyst, the polymerization stability of the liquid phase of the reaction system is low. There is room for further ingenuity in order to sufficiently prevent polymerization in the liquid phase.

[0006] The present invention has been made in consideration of the above-mentioned current situation, and an object of the present invention is to provide a method for sufficiently preventing polymerization in the liquid phase when producing a (meth)acrylic acid ester having a vinyl ether group by a transesterification reaction. [Means for solving the problem]

[0007] The present inventors have conducted various studies on methods for sufficiently preventing polymerization in the liquid phase when producing a (meth)acrylic ester having a vinyl ether group by transesterification, and have focused on the agent to be used. Then, the present inventors have produced a (meth)acrylic ester having a vinyl ether group by making the raw material solution contain 0.2 mass% or more of a specific phenolic antioxidant and a phosphorous ester together with the raw material (meth)acrylic ester, a hydroxyl group-containing vinyl ether compound, and a catalyst, and have found that polymerization in the liquid phase can be sufficiently prevented. They have come to the conclusion that the above-mentioned problem can be successfully solved, and have arrived at the present invention.

[0008] That is, the present invention (1) is a method for producing a (meth)acrylic ester having a vinyl ether group, comprising a step of obtaining a (meth)acrylic ester having a vinyl ether group by transesterification using a raw material solution containing a raw material (meth)acrylic ester, a hydroxyl group-containing vinyl ether compound, and a catalyst, wherein the raw material solution further contains a compound represented by the following formula (1) and a phosphite, and the mass ratio of the compound represented by the following formula (1) in the raw material solution is 0.2 mass% or more, and the mass ratio of the phosphite is 0.2 mass% or more. [ka] In the above formula, R 1 ~R 4 are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. m, n, p and q are the same or different and each represents an integer of 1 to 4. It is.

[0009] The present invention (2) relates to the method for producing a (meth)acrylic acid ester having a vinyl ether group according to the present invention (1), characterized in that the hydroxyl group-containing vinyl ether compound is diethylene glycol monovinyl ether, and the (meth)acrylic acid ester having a vinyl ether group is 2-(2-vinyloxyethoxy)ethyl (meth)acrylate. Effect of the Invention

[0010] The process for producing a (meth)acrylic acid ester having a vinyl ether group of the present invention has the above-mentioned configuration and can sufficiently prevent polymerization of the (meth)acryloyl group in the liquid phase. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of a manufacturing apparatus for carrying out the manufacturing method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

[0013] <Step of Obtaining a (Meth)acrylic Acid Ester Having a Vinyl Ether Group> The production method of the present invention includes a step of obtaining a (meth)acrylic ester having a vinyl ether group by transesterification using a raw material solution containing a raw material (meth)acrylic ester, a hydroxyl group-containing vinyl ether compound, and a catalyst, the raw material solution further containing a compound represented by the above formula (1) and a phosphite, the mass ratio of the compound represented by the above formula (1) being 0.2 mass% or more and the mass ratio of the phosphite being 0.2 mass% or more in the raw material solution. In this specification, the step of obtaining a (meth)acrylic ester having a vinyl ether group by transesterification is also referred to as a reaction step.

[0014] In this specification, the term "(meth)acrylic acid ester" refers to an acrylic acid ester and / or a methacrylic acid ester, and the term "(meth)acryloyl group" refers to an acryloyl group and / or a methacryloyl group.

[0015] (Compound represented by formula (1)) In the production method of the present invention, the raw material solution contains 0.2 mass % or more of the compound represented by the above formula (1). When the raw material solution contains 0.2 mass % or more of the compound represented by the above formula (1) and 0.2 mass % or more of a phosphite ester described below, these compounds exert their synergistic effects as a polymerization inhibitor, and polymerization in the liquid phase can be sufficiently prevented.

[0016] In the above formula, R 1 ~R 4 R are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. 1 ~R 4 preferably, at least one of R represents the hydrocarbon group, more preferably, at least two of R represents the hydrocarbon group, and further preferably, at least three of R represents the hydrocarbon group; 1 ~R 4 It is particularly preferred that all of the following represent said hydrocarbon group.

[0017] Examples of the hydrocarbon group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, and a pentyl group. The above-mentioned hydrocarbon group having 1 to 5 carbon atoms preferably has 2 to 5 carbon atoms, more preferably 3 to 5 carbon atoms, even more preferably 4 or 5 carbon atoms, and even more preferably 4. The above-mentioned hydrocarbon group having 1 to 5 carbon atoms is particularly preferably a t-butyl group.

[0018] m, n, p, and q are the same or different and are integers of 1 to 4. m, n, p, and q are preferably integers of 1 to 3, more preferably 1 or 2, and even more preferably 2.

[0019] The mass ratio of the compound represented by the above formula (1) in the raw material solution is preferably 0.3 mass% or more, more preferably 0.4 mass% or more, and from the viewpoint of preventing the effect from being saturated, the mass ratio is preferably 5 mass% or less, more preferably 3 mass% or less, and even more preferably 1 mass% or less.

[0020] In this specification, the mass ratio in the raw material solution refers to the mass ratio in the raw material solution immediately before being subjected to the reaction step. The raw material solution may be charged in a reaction apparatus such as a reaction tank all at once, or may be supplied to the reaction apparatus continuously or intermittently.

[0021] (Phosphite ester) In the production method of the present invention, the raw material solution contains 0.2 mass % or more of a phosphite. The above-mentioned phosphite acts as a secondary antioxidant that decomposes peroxides produced in the liquid phase of the reaction system in the reaction step of the present invention, thereby inhibiting polymerization reactions involving peroxides.

[0022] Specific examples of the above phosphorous ester include triphenyl phosphite (TPP), tris(2,4-di-tert-butylphenyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite (BPOP), diphenyl mono(tridecyl)phosphite, diphenyl monodecylphosphite, cyclic neopentatetraylbis(octadecylphosphite), trioleylphosphite, etc., and one or more of these can be used. Among these, TPP, tris(2,4-di-tert-butylphenyl)phosphite, BPOP, diphenyl mono(tridecyl)phosphite, and diphenyl monodecylphosphite are preferred, and TPP, tris(2,4-di-tert-butylphenyl)phosphite, and BPOP are more preferred. More preferred are TPP and tris(2,4-di-tert-butylphenyl)phosphite, and particularly preferred is tris(2,4-di-tert-butylphenyl)phosphite.

[0023] The mass ratio of the phosphite in the raw material solution is preferably 0.3 mass% or more, more preferably 0.4 mass% or more, and from the viewpoint of preventing the effect from becoming saturated, the mass ratio is preferably 5 mass% or less, more preferably 3 mass% or less, and even more preferably 1 mass% or less.

[0024] (Raw material (meth)acrylic ester) The raw material (meth)acrylic acid ester is not particularly limited as long as it can be transesterified with a hydroxyl group-containing vinyl ether compound to produce a (meth)acrylic acid ester having a vinyl ether group, and one or more of them can be used.

[0025] [ka]

[0026] (In the formula, R 1 R represents a hydrogen atom or a methyl group. 3represents an organic group. R in the above general formula (2) 3 The organic group represented by the formula (I) is not particularly limited, but for example, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, or an aromatic group having 6 to 10 carbon atoms which may be substituted, etc. are preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable.

[0027] Examples of the raw material (meth)acrylic acid ester represented by the above general formula (2) include lower alkyl (meth)acrylate esters (the alkyl group of the alkyl ester has 1 to 4 carbon atoms), such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate. Among these, methyl acrylate (AM), methyl methacrylate, ethyl acrylate, and ethyl methacrylate are preferred, and methyl acrylate (AM) and ethyl acrylate are more preferred.

[0028] The raw material (meth)acrylic acid ester is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, still more preferably 40% by mass or more, and particularly preferably 50% by mass or more in 100% by mass of the raw material solution. The mass ratio of the raw material (meth)acrylic acid ester is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and particularly preferably 65% ​​by mass or less. When two or more kinds of the raw material (meth)acrylic acid esters are used, the above mass ratio is the mass ratio of the total.

[0029] (Hydroxyl group-containing vinyl ether compound) The hydroxyl group-containing vinyl ether compound is not particularly limited as long as it contains a hydroxyl group and a vinyl ether group and can undergo an ester exchange reaction with a raw material (meth)acrylic acid ester to produce a (meth)acrylic acid ester having a vinyl ether group, and one or more of them can be used. Among them, a preferred example is a compound represented by the following general formula (3):

[0030] [ka]

[0031] (In the formula, R 2 represents an organic group. Preferred are hydroxyl group-containing vinyl ether compounds represented by the following formula:

[0032] In the hydroxyl group-containing vinyl ether compound represented by the above general formula (3), R 2 The organic group represented by the formula (1) is not particularly limited, and examples thereof include linear, branched or cyclic alkylene groups having 2 to 20 carbon atoms, alkylene groups having 2 to 20 carbon atoms having an oxygen atom in the structure via an ether bond and / or an ester bond, and aromatic groups having 6 to 11 carbon atoms which may be substituted. Among these, alkylene groups having 2 to 6 carbon atoms and alkylene groups having 4 to 10 carbon atoms having an oxygen atom in the structure via an ether bond are preferred.

[0033] Examples of the hydroxyl group-containing vinyl ether compound represented by the above general formula (3) include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxyisopropyl vinyl ether, 4-hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-hydroxybutyl vinyl ether, 3-hydroxyisobutyl vinyl ether, 2-hydroxyisobutyl vinyl ether, 1-methyl-3-hydroxypropyl vinyl ether, 1-methyl-2-hydroxypropyl vinyl ether, 1-hydroxymethylpropyl vinyl ether, 4-hydroxycyclohexyl vinyl ether, 1,6-hexanediol monovinyl ether, 1,4-cyclohexanedimethanol monovinyl ether, 1,3-cyclohexanedimethanol monovinyl ether, 1,2-cyclohexanedimethanol monovinyl ether, Examples of the vinyl ether include vinyl ether, p-xylene glycol monovinyl ether, m-xylene glycol monovinyl ether, o-xylene glycol monovinyl ether, diethylene glycol monovinyl ether (DEGV), triethylene glycol monovinyl ether, tetraethylene glycol monovinyl ether, pentaethylene glycol monovinyl ether, oligoethylene glycol monovinyl ether, polyethylene glycol monovinyl ether, dipropylene glycol monovinyl ether, tripropylene glycol monovinyl ether, tetrapropylene glycol monovinyl ether, pentapropylene glycol monovinyl ether, oligopropylene glycol monovinyl ether, polypropylene glycol monovinyl ether, and ethylene glycol-propylene glycol copolymer monovinyl ether. One or more of these may be used.

[0034] Of the hydroxyl group-containing vinyl ether compounds represented by the above general formula (3), 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxyisopropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxycyclohexyl vinyl ether, 1,6-hexanediol monovinyl ether, 1,4-cyclohexanedimethanol monovinyl ether, DEGV, triethylene glycol monovinyl ether, and dipropylene glycol monovinyl ether are preferred, and DEGV is more preferred.

[0035] The amount of the hydroxyl group-containing vinyl ether compound is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 35% by mass or more, based on 100% by mass of the raw material solution. The mass proportion of the hydroxyl group-containing vinyl ether compound is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, and particularly preferably 50% by mass or less. When two or more kinds of the hydroxyl group-containing vinyl ether compounds are used, the above mass ratio is the total mass ratio thereof.

[0036] In the above reaction step, the molar ratio of the raw material (meth)acrylic acid ester to the hydroxyl group-containing vinyl ether compound can be appropriately set depending on the combination of the types of raw material (meth)acrylic acid ester and hydroxyl group-containing vinyl ether compound, but is preferably, for example, 20 / 1 to 1 / 5. A blending ratio in this range is preferable in terms of yield and economic efficiency. More preferably, it is 15 / 1 to 1 / 3, and even more preferably, it is 10 / 1 to 1 / 2. Particularly preferably, it is 5 / 1 to 1 / 1.

[0037] (catalyst) The catalyst is not particularly limited as long as it has the effect of accelerating the transesterification reaction, and examples of the catalyst include oxides such as calcium oxide, barium oxide, lead oxide, zinc oxide, and zirconium oxide; hydroxides such as potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, thallium hydroxide, tin hydroxide, lead hydroxide, and nickel hydroxide; halides such as lithium chloride, calcium chloride, tin chloride, lead chloride, zirconium chloride, and nickel chloride; carbonates such as potassium carbonate, rubidium carbonate, cesium carbonate, lead carbonate, zinc carbonate, and nickel carbonate; hydrogen carbonates such as potassium hydrogen carbonate, rubidium hydrogen carbonate, and cesium hydrogen carbonate; phosphates such as sodium phosphate, potassium phosphate, rubidium phosphate, lead phosphate, zinc phosphate, and nickel phosphate; nitrates such as lithium nitrate, calcium nitrate, lead nitrate, zinc nitrate, and nickel nitrate; carboxylates such as lithium acetate, calcium acetate, lead acetate, zinc acetate, and nickel acetate; sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, potassium t-butoxide, calcium alkoxy compounds such as titanium methoxide, calcium ethoxide, barium methoxide, barium ethoxide, tetraethoxytitanium, tetrabutoxytitanium, and tetra(2-ethylhexanoxy)titanium; acetylacetonate complexes such as lithium acetylacetonate, zirconia acetylacetonate, zinc acetylacetonate, dibutoxytin acetylacetonate, and dibutoxytitanium acetylacetonate; quaternary ammonium alkoxides such as tetramethylammonium methoxide, tetramethylammonium t-butoxide, and trimethylbenzylammonium ethoxide; dialkyltin compounds such as dimethyltin oxide, methylbutyltin oxide, dibutyltin oxide (DBTO), and dioctyltin oxide; distannoxanes such as bis(dibutyltin acetate) oxide and bis(dibutyltin laurate) oxide; and dialkyltin dicarboxylates such as dibutyltin diacetate and dibutyltin dilaurate (DBTL). One or more of these can be used.

[0038] Among these catalysts, potassium carbonate, cesium carbonate, tetraethoxytitanium, tetrabutoxytitanium, tetra(2-ethylhexanoxy)titanium, zirconia acetylacetonate, DBTO, dioctyltin oxide, bis(dibutyltin acetate) oxide, bis(dibutyltin laurate) oxide, dibutyltin diacetate, and DBTL are preferably used, and more preferably DBTO and DBTL.

[0039] The catalyst is preferably present in an amount of 100 ppm or more, more preferably 500 ppm or more, and even more preferably 1000 ppm or more, relative to 100% by mass of the raw material solution. The mass ratio of the catalyst is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. When two or more of the above catalysts are used, the above mass ratio is the total mass ratio thereof.

[0040] The amount of the catalyst used is not particularly limited and can be appropriately set, but is preferably in the range of 0.0001 to 20 mol% relative to 100 mol% of the hydroxyl group-containing vinyl ether compound. From the viewpoints of yield and economy, it is preferable that the amount of the catalyst used is in such a range. It is more preferably 0.0003 to 15 mol%, even more preferably 0.0005 to 10 mol%, and particularly preferably 0.001 to 5 mol%.

[0041] (Primary antioxidant) The raw material solution preferably further contains a primary antioxidant. The primary antioxidant is not particularly limited as long as it can capture and decompose the peroxy radicals generated in the liquid phase of the reaction system in the reaction step of the present invention, thereby suppressing the radical polymerization reaction involving the peroxy radicals. For example, phenol-based antioxidants such as hydroquinone, methoxyhydroquinone, hydroquinone monomethyl ether (MEHQ), benzoquinone, p-tert-butylcatechol, 2,6-di-tert-butylphenol, 2,4-di-tert-butylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,4,6-tri-tert-butylphenol, 3,5-di-tert-butyl-4-hydroxytoluene (BHT), and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (TPB); alkylated diphenylamine, N,N'-diphenyl-p-phenylenediamine, phenotypic antioxidants such as phenylmethylsuccinimide, ... aromatic amine antioxidants such as azine (PTZ); cyclic amine antioxidants such as 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1,4-dihydroxy-2,2,6,6-tetramethylpiperidine, and 1-hydroxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine; copper dimethyldithiocarbamate, copper diethyldithiocarbamate, Examples of the primary antioxidant include copper dithiocarbamate antioxidants such as copper dibutyldithiocarbamate; and N-oxyl antioxidants such as 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl, and esters of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl. Among these, the primary antioxidant is preferably a phenolic antioxidant or an aromatic amine antioxidant. Thus, the embodiment in which the primary antioxidant is a phenolic antioxidant and / or an aromatic amine antioxidant is also one of the preferred embodiments of the present invention. As the primary antioxidant, hydroquinone, MEHQ, 3,5-di-tert-butyl-4-hydroxytoluene, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, and PTZ are more preferred.

[0042] The content of the primary antioxidant is preferably 100 ppm or more, more preferably 500 ppm or more, and even more preferably 1000 ppm or more, based on 100% by mass of the raw material solution. The mass proportion of the primary antioxidant is preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 5000 ppm or less. When two or more types of the primary antioxidants are used, the above mass ratio is the total mass ratio thereof.

[0043] In the reaction step of the present invention, the amount of the primary antioxidant used is preferably 2 ppm to 5 mass% relative to 100 mass% of the hydroxyl group-containing vinyl ether compound, which is the reaction raw material. The amount of the primary antioxidant used is preferably within such a range in terms of yield, inhibition of polymerization in the liquid phase of the reaction system, and economic efficiency. The amount used is more preferably 10 ppm to 3 mass%, further preferably 50 ppm to 1 mass%, and particularly preferably 100 ppm to 5000 ppm.

[0044] (Secondary antioxidant) The raw material solution contains 0.2% by mass or more of a phosphite ester as a secondary antioxidant, and may further contain other secondary antioxidants such as thioethers.

[0045] Specific examples of the thioether include dilauryl 3,3'-thiodipropionate (TDPL), distearyl 3,3'-thiodipropionate, didodecyl 3,3'-thiodipropionate, dioctadecyl 3,3'-thiodipropionate, and pentaerythritol tetrakis(β-laurylthiopropionic acid).

[0046] The feedstock solution may further include other secondary antioxidants, such as, for example, tris(2,4-di-t-butylphenyl)phosphite (DBPP).

[0047] The amount of the other secondary antioxidants is preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 5000 ppm or less, relative to 100% by mass of the raw material solution. When two or more of the above-mentioned other secondary antioxidants are used, the above mass ratio is the total mass ratio thereof.

[0048] In the reaction step of the present invention, the amount of the other secondary antioxidants in the raw solution is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and particularly preferably 5000 ppm or less, based on 100% by mass of the hydroxyl-containing vinyl ether compound as the raw material.

[0049] ((Meth)acrylic acid ester having a vinyl ether group) In the production method of the present invention, a (meth)acrylic acid ester having a vinyl ether group is produced by transesterification of a raw material (meth)acrylic acid ester and a hydroxyl group-containing vinyl ether compound. Therefore, the obtained (meth)acrylic acid ester having a vinyl ether group is a compound synthesized by transesterification of a compound selected from the raw material (meth)acrylic acid ester and the hydroxyl group-containing vinyl ether compound. In this specification, the target product, a (meth)acrylic acid ester having a vinyl ether group, is also simply referred to as a (meth)acrylic acid ester having a vinyl ether group. In particular, when the raw material (meth)acrylic acid ester is a compound represented by general formula (2) and the hydroxyl group-containing vinyl ether compound is a compound represented by general formula (3), the (meth)acrylic acid ester having a vinyl ether group is a compound represented by the following general formula (4);

[0050] [ka]

[0051] (In the formula, R 1 R represents a hydrogen atom or a methyl group. 2 represents an organic group.) In this way, the embodiment in which the (meth)acrylic acid ester having a vinyl ether group is a (meth)acrylic acid ester having a vinyl ether group represented by general formula (4) is also one of the preferred embodiments of the present invention. In addition, R in the general formula (4) 1 is R in general formula (2). 1 The same as R in general formula (4). 2 is R in general formula (3). 2 is the same as:

[0052] Specific examples of the (meth)acrylic acid ester having a vinyl ether group represented by the above general formula (4) include 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, and (meth)acrylic acid. 1,1-Dimethyl-2-vinyloxyethyl, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, 3-vinyloxymethylcyclohexylmethyl (meth)acrylate, 2-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate , m-vinyloxymethylphenylmethyl (meth)acrylate, o-vinyloxymethylphenylmethyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate (meth)acrylate 2-(vinyloxyethoxyisopropoxy)ethyl, (meth)acrylate 2-(vinyloxyisopropoxyethoxy)ethyl, (meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)ethyl, (meth)acrylate 2-(vinyloxyethoxyethoxy)propyl, (meth)acrylate 2-(vinyloxyethoxyisopropoxy)propyl, (meth)acrylate 2-(vinyloxyisopropoxyethoxy)propyl, (meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)propyl, (meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)propyl,2-(vinyloxyethoxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropoxyethoxy)ethyl (meth)acrylate, 2-(isopropoxy Examples of suitable vinyl acrylates include 2-(vinyloxyethoxy)ethyl acrylate, 2-(isopropoxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropoxyethoxyethoxyethoxy)ethyl (meth)acrylate, polyethylene glycol monovinyl ether (meth)acrylate, and polypropylene glycol monovinyl ether (meth)acrylate. Among these, 2-(vinyloxyethoxy)ethyl acrylate (VEEA (registered trademark)) and 2-(vinyloxyethoxy)ethyl methacrylate (VEEM (registered trademark)) are preferred, and 2-(vinyloxyethoxy)ethyl acrylate is more preferred. 2-(vinyloxyethoxy)ethyl acrylate is particularly prone to polymerization, but by applying the production method of the present invention, polymerization in the liquid phase can be sufficiently prevented.

[0053] The reaction step is preferably carried out in an atmosphere in which the molecular oxygen concentration in the gas phase of the reaction system is 0.001 to 21% by volume. By setting the molecular oxygen concentration in the gas phase in this range, the polymerization reaction in the reaction step can be more effectively prevented, and the (meth)acrylic acid ester having a vinyl ether group can be produced in a high yield. The molecular oxygen concentration in the gas phase is more preferably 0.005 to 15% by volume, and even more preferably 0.01 to 10% by volume.

[0054] Methods for adjusting the molecular oxygen concentration in the gas phase of the reaction system to the above-mentioned preferred range include (a) a method of supplying molecular oxygen or a gas containing molecular oxygen such as air to a reaction vessel during the reaction (where steam is present) to adjust the molecular oxygen concentration in the gas phase, (b) a method of supplying molecular oxygen or a gas containing molecular oxygen such as air and an inert gas such as nitrogen or argon to a reaction vessel during the reaction (where steam is present) to adjust the molecular oxygen concentration in the gas phase, and (c) a method of premixing molecular oxygen or a gas containing molecular oxygen such as air with an inert gas such as nitrogen or argon and supplying the mixture to a reaction vessel during the reaction (where steam is present) to adjust the molecular oxygen concentration in the gas phase. The method for supplying molecular oxygen and / or a mixed gas containing molecular oxygen to the reaction system may be to supply it continuously or intermittently to either or both of the liquid phase and the gas phase in the reaction system.

[0055] In addition, since the reaction in the above reaction step is an ester exchange reaction, alcohol is produced as a by-product as the reaction proceeds. It is preferable to remove the by-product alcohol from the reaction system. Examples of the method for removing the by-produced alcohol include a method of carrying out the reaction under reduced pressure, a method of carrying out the reaction using an azeotropic solvent, a method of carrying out the reaction in the presence of an adsorbent, etc. Among these, the method of carrying out the reaction under reduced pressure and the method of carrying out the reaction using an azeotropic solvent are preferred.

[0056] The azeotropic solvent is not particularly limited as long as it does not inhibit the transesterification reaction, and examples thereof include ethers such as diethyl ether, diisopropyl ether, and dibutyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as pentane, hexane, heptane, and cyclohexane; and halogenated hydrocarbons such as chloroform, methylene chloride, 1,2-dichloroethane, and chlorobenzene. These azeotropic solvents may be used alone or in combination of two or more. In addition, the raw material (meth)acrylic acid ester used in excess may be used as the azeotropic solvent.

[0057] The amount of the azeotropic solvent used is not particularly limited, but is preferably 0 to 300% by mass of the hydroxyl group-containing vinyl ether compound, which is the reaction raw material. From the viewpoints of yield and economy, it is preferable that the amount of the azeotropic solvent used is within such a range. The amount used is more preferably 1 to 200% by mass, further preferably 2 to 150% by mass, and particularly preferably 3 to 100% by mass.

[0058] The reaction temperature in the reaction step is not particularly limited, but is preferably equal to or higher than the boiling point or azeotropic temperature of the by-produced alcohol, and specifically, is preferably equal to or higher than 40°C, more preferably equal to or higher than 50°C, and even more preferably equal to or higher than 60°C. This allows the by-produced alcohol to be sufficiently removed. The reaction temperature is preferably equal to or lower than 180°C, more preferably equal to or lower than 140°C, and even more preferably equal to or lower than 100°C. This makes it difficult for the polymerization reaction of the easily polymerizable compound to proceed, and thus the polymerization inhibition effect becomes more remarkable. The reaction pressure is not particularly limited, and may be normal pressure, pressurized pressure, or reduced pressure, but as described above, reduced pressure is preferable from the viewpoint of removing the by-produced alcohol. The reaction time may be appropriately set so that the reaction in the reaction step is completed, and may be, for example, 3 to 20 hours.

[0059] The production method of the present invention may include other steps described below so long as it includes the above reaction step.

[0060] [Purification after reaction process] In the production method of the present invention, after the above reaction step, the resulting (meth)acrylic acid ester having a vinyl ether group can be purified and separated from the reaction solution. The method for carrying out the purification step is not particularly limited, but examples thereof include a raw material recovery operation, a catalyst recovery operation, a neutralization operation, a filtration operation, a decantation operation, an extraction operation, a water washing operation, an evaporation operation, a distillation operation, and a column chromatography operation. The above-mentioned operations can be carried out alone or in combination of two or more. Among these, purification by distillation is particularly preferred. Furthermore, the impurities removed by purification can be reused as raw materials or agents, if necessary.

[0061] <Separation process of raw material (meth)acrylic acid ester> For example, the production method of the present invention preferably includes a step of separating the unreacted raw material (meth)acrylic acid ester after the above reaction step. In the step of separating the raw material (meth)acrylic acid ester, the raw material (meth)acrylic acid ester is preferably separated by evaporation through distillation. The separated raw material (meth)acrylic acid ester can be recovered and reused as a raw material (meth)acrylic acid ester in the reaction step.

[0062] The temperature in the separation step of the raw material (meth)acrylic acid ester can be appropriately set based on the boiling point of the raw material (meth)acrylic acid ester. The pressure is not particularly limited and may be normal pressure, increased pressure, or reduced pressure, but reduced pressure is preferred. The time may be appropriately set so that the raw material (meth)acrylic acid ester can be sufficiently removed.

[0063] <Catalyst separation process> For example, the production method of the present invention preferably includes a step of separating the catalyst after the reaction step. In the catalyst separation step, the catalyst is preferably separated by evaporating the target product, the (meth)acrylic acid ester having a vinyl ether group, by distillation, which makes it possible to remove impurities having a higher boiling point than the target product, the (meth)acrylic acid ester having a vinyl ether group, together with the catalyst.

[0064] The temperature in the catalyst separation step is usually higher than the temperature in the raw material (meth)acrylic acid ester separation step, and can be appropriately set based on the boiling point of the target product, the (meth)acrylic acid ester having a vinyl ether group, etc. The pressure is not particularly limited and may be normal pressure, increased pressure, or reduced pressure, but reduced pressure is preferred. The time may be appropriately set.

[0065] <Purification process of (meth)acrylic acid ester having vinyl ether group> The production method of the present invention preferably further includes a step of purifying the (meth)acrylic ester having a vinyl ether group, for example, after the reaction step, the raw material (meth)acrylic ester separation step, and the catalyst separation step. In the purification step of the (meth)acrylic acid ester having a vinyl ether group, it is preferable to separate the (meth)acrylic acid ester having a vinyl ether group by evaporating it by distillation. This makes it possible to remove impurities having a higher boiling point than the (meth)acrylic acid ester having a vinyl ether group. In addition, for example, it is more preferable to remove the (meth)acrylic acid ester having a vinyl ether group by evaporating it by distillation after removing the impurities having a lower boiling point than the (meth)acrylic acid ester having a vinyl ether group. The purification step of the (meth)acrylic acid ester having a vinyl ether group is preferably carried out using a rectification column, such as an Oldershaw type rectification column.

[0066] The temperature in the purification step of the (meth)acrylic acid ester having a vinyl ether group can be appropriately set based on the boiling point of the (meth)acrylic acid ester having a vinyl ether group and the boiling points of impurities. The pressure is not particularly limited and may be normal pressure, increased pressure, or reduced pressure, but reduced pressure is preferred. The time may be appropriately set.

[0067] FIG. 1 is a diagram showing an example of a production apparatus for carrying out the production method of the present invention. FIG. 1 shows an apparatus equipped with a reaction tank 11 for an ester exchange reaction, a first distillation column 21 for evaporating a raw material (meth)acrylic acid ester and separating it from a (meth)acrylic acid ester having a vinyl ether group, and a second distillation column 31 for evaporating the (meth)acrylic acid ester having a vinyl ether group and separating a catalyst and high-boiling-point impurities from the (meth)acrylic acid ester having a vinyl ether group.

[0068] The raw material solution 1 to be fed to the apparatus is first introduced into the reaction tank 11. When the transesterification reaction is carried out in the reaction tank 11, the mass ratio of the compound represented by formula (1) and the phosphorous ester in the raw material solution 1 is 0.8 mass% or more, respectively, so that the (meth)acrylic ester having a vinyl ether group can be obtained while sufficiently preventing the polymerization of the (meth)acryloyl group. Although not shown, the alcohol by-produced in the transesterification reaction is usually a low-boiling component, and can be evaporated and removed from the reaction tank 11. The obtained solution containing the (meth)acrylic ester having a vinyl ether group is sent to the first distillation tower 21 via line 71. In the first distillation tower 21, the unreacted raw material (meth)acrylic ester is evaporated and separated. The separated raw material (meth)acrylic ester is returned to the reaction tank 11 via line 81. The solution containing the (meth)acrylic ester having a vinyl ether group, which is the bottom liquid in the first distillation tower 21, is sent to the second distillation tower 31 via line 72. In the second distillation column 31, the (meth)acrylic acid ester having a vinyl ether group is evaporated, and a crude product 3 is obtained from the top of the second distillation column 31. The bottom liquid in the second distillation column 31 contains a large amount of impurities, such as a catalyst, that have a higher boiling point than the (meth)acrylic acid ester having a vinyl ether group, and is therefore removed as waste oil 2.

[0069] The (meth)acrylic ester having a vinyl ether group obtained by the production method of the present invention can be suitably used as a raw material for various industrial products. EXAMPLES

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "parts" means "parts by weight" and "%" means "% by mass".

[0071] [Production Example 1] A 2-L glass round-bottom flask (reactor) equipped with an Oldershaw type rectification column, a stirrer, a thermometer, a gas inlet tube, and a liquid sequential introduction line was prepared. 620 g of methyl acrylate (hereinafter abbreviated as "AM"), 453 g of diethylene glycol monovinyl ether (hereinafter abbreviated as "DEGV"), 1.1 g of phenothiazine (hereinafter abbreviated as "PTZ") as a primary antioxidant, 0.32 g of N-nitrosophenylhydroxyamine ammonium salt (hereinafter abbreviated as "NPHN"), and 2.1 g of dibutyltin oxide (hereinafter abbreviated as "DBTO") as a catalyst were charged into the round-bottom flask. Next, the reactor was immersed in an oil bath at 120°C while bubbling a liquid phase of oxygen / nitrogen mixed gas, the oxygen concentration of which was adjusted to 7% by volume, through the gas inlet tube at 15 ml / min, and heating was started under total reflux conditions. As the reaction proceeded, methanol, a by-product, was concentrated at the top of the Oldershaw type rectification column, and after the temperature at the top of the column reached 63°C, which is the azeotropic point of AM and methanol, distillation was started at a reflux ratio of 8 and a withdrawal rate of 50 g / h. At the same time, AM was fed to the reactor through a liquid successive injection line at a rate equal to the distillation rate. The reaction was carried out for 8 hours, with the start of distillation being the start of the reaction (reaction time 0 hours). Next, the reaction liquid after the reaction was subjected to simple distillation (operation pressure 20 hPa; ended when the liquid temperature reached 100°C) to remove unreacted AM, and further the reaction product was distilled off at an operating pressure of 20 hPa and a distillation rate of 75% (distillation at a constant distillation rate for 14 hours). In this way, a residue containing the catalyst was obtained as a test liquid for the liquid polymerization stability test.

[0072] [Example 1] Into a transparent glass test tube (inner diameter 18 mm, length 180 mm; manufactured by Maruemu Co., Ltd.), 5 g of the test liquid obtained in Production Example 1 and 0.05 g each of N,N'-bis{2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyl]ethyl}oxamide (product name: Antage HP-200 / Kawaguchi Chemical) (hereinafter abbreviated as "HP-200") and tris(2,4-di-t-butylphenyl)phosphite (product name: JP-650 / Johoku Chemical Industry) (hereinafter abbreviated as "JP-650") (each 1% by mass relative to the test liquid) were added as polymerization inhibitors. Next, the test tube was sealed with a silicone stopper and then immersed in an oil bath at 100°C to measure the polymerization time. Polymerization was considered to have occurred when a part of the test liquid was found to have solidified, and the time up to that point was recorded as the polymerization time. The results are shown in Table 1.

[0073] [Comparative Examples 1 to 3] The amount of polymerization inhibitor added was changed as shown in Table 1, and the liquid polymerization stability test described in Example 1 was carried out. The results are shown in Table 1.

[0074] [Table 1]

[0075] (summary) In Comparative Example 1, in which no polymerization inhibitor was added, Comparative Examples 2 and 3, in which only one type of polymerization inhibitor was used alone, tended to extend the polymerization time and improve the liquid stability. Furthermore, in Example 1, in which two types of polymerization inhibitors were used in combination, the polymerization time was further extended, indicating that a synergistic effect was achieved by using two types in combination.

[0076] [Comparative Example 4] A jacketed reactive distillation reactor was charged with 1,364 kg of AM, 997 kg of DEGV, 2.4 kg of PTZ as a primary antioxidant, 0.70 kg of NPHN, and 4.6 kg of DBTO as a catalyst. Next, while bubbling an oxygen / nitrogen mixed gas with an oxygen concentration adjusted to 7% by volume through the gas inlet tube at 2 Nm3 / h into the liquid, steam was supplied to the jacket under total reflux conditions to start raising the temperature. The reaction temperature was set to 120°C. As the reaction proceeded, methanol, a by-product, was concentrated at the top of the distillation tower, and after the temperature at the top of the tower reached 63°C, which is the azeotropic point of AM and methanol, distillation was started at a reflux ratio of 8 and a flow rate of 110 kg / h. At the same time, AM was fed to the reaction vessel through a liquid sequential feed line at the same flow rate. The reaction was carried out in one batch for 8 hours, with the start of distillation being the start of the reaction (reaction time 0 hours). In addition, in order to prevent polymerization inside the reaction vessel, a 1% by mass PTZ / AM solution was fed from the top of the distillation tower at a flow rate of 11 kg / h. Next, the unreacted AM in the reaction liquid after the completion of the reaction was distilled off (operating pressure 20 hPa; the process was completed when the liquid temperature reached 100°C), and then the reaction product was distilled off over 14 hours at an operating pressure of 20 hPa and a distillation rate of 75% (constant distillation rate) (catalyst separation process). The above reaction and distillation were repeated, and during the eighth reaction (eighth batch), an abnormality occurred in the current value of the pump that transports the column bottom liquid after catalyst separation in the catalyst separation process, and operation was stopped. When the area around the pump was checked, it was found that polymers, the reaction products, had formed in the pump's suction strainer and piping, causing blockages.

[0077] [Comparative Example 5] The same procedure as in Comparative Example 4 was carried out, except that JP-650 was added as a polymerization inhibitor to the reaction liquid so that the amount was 0.2% by mass. As a result, during the 10th reaction (10th batch), an abnormality occurred in the current value of the pump that transports the column bottom liquid after catalyst separation in the catalyst separation process, and operation was stopped. When the surrounding area of ​​the pump was checked, it was found that polymers, a reaction product, had formed in the pump's suction strainer and piping, causing blockages.

[0078] [Comparative Example 6] The same procedure as in Comparative Example 4 was carried out, except that HP-200 was added as a polymerization inhibitor to give a concentration of 0.2% by mass relative to the reaction liquid. As a result, during the 58th reaction (58th batch), an abnormality occurred in the current value of the pump that transports the column bottom liquid after catalyst separation in the catalyst separation process, and operation was stopped. When the surrounding area of ​​the pump was checked, it was found that polymers, a reaction product, had formed in the pump's suction strainer and piping, causing blockages.

[0079] [Example 2] The same procedure as in Comparative Example 4 was carried out, except that JP-650 and HP-200 were added as polymerization inhibitors to the reaction liquid so that each amount was 0.2% by mass. As a result, even in the 80th reaction (80th batch), no abnormalities occurred in the pump transporting the column bottom liquid after catalyst separation, and an internal inspection after operation found no blockages due to polymer in the piping, etc.

[0080] [Table 2]

[0081] (summary) It was confirmed that the combined use of two types of polymerization inhibitors (HP-200 and JP-650) provided a superior polymerization inhibition effect compared to the use of either agent alone. [Explanation of symbols]

[0082] 1: Raw material solution 2: Waste oil 3: Product (unfinished product) 11: Reactor 21: First distillation tower 31: Second distillation tower 71, 72, 81: Line

Claims

1. A method for producing a (meth)acrylic ester having a vinyl ether group, comprising the step of obtaining a (meth)acrylic ester having a vinyl ether group by transesterification using a raw material solution containing a raw material (meth)acrylic ester, a hydroxyl group-containing vinyl ether compound, and a catalyst, The raw material solution further contains a compound represented by the following formula (1) and a phosphite, and the mass ratio of the compound represented by the following formula (1) in the raw material solution is 0.2 mass% or more, and the mass ratio of the phosphite in the raw material solution is 0.2 mass% or more. 【Chemistry 1】 In the above formula, R １ ~R ４ are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and m, n, p and q are the same or different and each represents an integer of 1 to 4.

2. The hydroxyl group-containing vinyl ether compound is diethylene glycol monovinyl ether, 2. The method for producing a (meth)acrylic ester having a vinyl ether group according to claim 1, wherein the (meth)acrylic ester having a vinyl ether group is 2-(2-vinyloxyethoxy)ethyl (meth)acrylate.

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