JP2001294557A - METHOD FOR PRODUCING alpha,beta-UNSATURATED CARBOXYLIC ESTER AND CATALYST TO BE USED THEREFOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for economically and efficiently producing an α,β-unsaturated carboxylic acid polyheteroalkyleneester sharp in the distribution of the addition number of moles of the cyclic heterocompound and containing substantially no α,β-unsaturated carboxylic diester, and to produce a catalyst suitable for the above method. SOLUTION: This method for producing an α,β-unsaturated carboxylic ester of the general formula comprises reaction between the corresponding α,β-unsaturated carboxylic ester and a cyclic heterocompound in the presence of a polymerization inhibitor and a metal oxide catalyst. The catalyst for the above method comprises a metal oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing polyheteroalkylene esters of α, β-unsaturated carboxylic acids. More specifically, a method for producing an α, β-unsaturated carboxylic acid polyheteroalkylene ester by reacting an α, β-unsaturated carboxylic acid with a cyclic hetero compound in the presence of a polymerization inhibitor and a metal oxide catalyst. And a catalyst that can be suitably used therefor.

[0002]

2. Description of the Related Art Since α, β-unsaturated carboxylic acid polyheteroalkylene esters have polymerizability, they are widely used industrially as fragrances, raw materials for medicines and agrochemicals, organic synthetic intermediates, polymerizable materials, and the like. A useful compound, for example, 2-hydroxyethyl (meth) acrylate is well known.

[0003] Such 2-hydroxyethyl (meth) acrylate is obtained by converting (meth) acrylic acid, which is an α, β-unsaturated carboxylic acid, and ethylene oxide, which is a cyclic hetero compound, into various amines and quaternary ammonium. There is known a method of producing a compound by reacting in the presence of a catalyst such as a salt, a trivalent iron compound, a chromium compound, silver or mercury, and an α, β-unsaturated carboxylic acid metal compound. However, in such a method for producing 2-hydroxyethyl (meth) acrylate, it is difficult to control the number of moles of ethylene oxide, which is a cyclic hetero compound, and the distribution of the number of moles becomes broad. There was a problem. In addition, a diester, which is a dimer in which α, β-unsaturated carboxylic acids are added to both ends of polyoxyalkylene, is generated. Especially when used for polymerization, the diester becomes a cross-linking agent and causes a problem such as gelation. It was with.

Japanese Patent Application Laid-Open No. 2000-16958 discloses a process for producing an alkylene oxide adduct in which an active hydrogen-containing organic compound is reacted with an alkylene oxide in the presence of a powdered magnesium oxide catalyst having a specific specific surface area. It is disclosed that less alkylene oxide adducts can be produced. However, there is no disclosure of a method for producing an α, β-unsaturated carboxylic acid polyheteroalkylene ester, which is a useful compound widely used industrially because of its polymerizability, and there is no disclosure of an α, β-unsaturated carboxylic acid. There was room for studying suitable methods for producing polyheteroalkylene esters.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above situation, and has a sharp distribution of the number of added moles of a cyclic hetero compound, and a diester of an α, β-unsaturated carboxylic acid. Method for economically and efficiently producing α, β-unsaturated carboxylic acid polyheteroalkylene esters containing no, and for producing economically and efficiently α, β-unsaturated carboxylic acid polyheteroalkylene esters It is also an object to provide a suitable catalyst.

[0006]

Means for Solving the Problems The present inventors have found that the distribution of the number of added moles of the cyclic hetero compound is sharp, and that the α, β-unsaturated compound containing almost no diester of α, β-unsaturated carboxylic acid ester. To provide a method for economically producing saturated carboxylic acid polyheteroalkylene esters,
As a result of intensive studies, it has been found that α, β-unsaturated carboxylic acids and cyclic hetero compounds are reacted economically with α, β-unsaturated carboxylic acids in the presence of a polymerization inhibitor and a metal oxide catalyst.
-It has been found that unsaturated carboxylic acid polyheteroalkylene esters can be produced, and it has been conceived that such an effect is more reliably exerted if the cyclic hetero compound has a specific chemical structure. Also, when the oxygen concentration in the gas phase of the reactor used when performing the reaction is specified,
The present inventors have also found that the polymerization of α, β-unsaturated carboxylic acids and α, β-unsaturated carboxylic acid polyheteroalkylene esters is suppressed, and that the present invention has a further effect, thereby completing the present invention.

That is, the present invention provides the following general formula (1):

[0008]

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(Wherein, R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom or an organic residue) and an α, β-unsaturated carboxylic acid represented by the following general formula ( 2);

[0010]

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(Wherein, R ⁴ represents a hydrogen atom or an organic residue; X ¹ represents O, S or NH) with a polymerization inhibitor and a metal oxide. Reacting in the presence of a catalyst of the following general formula (3):

[0012]

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(Wherein R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom or an organic residue. R ⁵ , R ^{5
Among 6} , ⁶ , R ⁷ and R ⁸ , any one of them represents R ⁴ , and the remaining three represent hydrogen atoms. X ¹ represents O, S or NH. n1 represents one or more positive numbers. ), Which comprises a reaction step of obtaining an α, β-unsaturated carboxylic acid ester represented by the formula (1). Hereinafter, the present invention will be described in detail.

The process for producing the α, β-unsaturated carboxylic acid ester of the present invention comprises the α, β-unsaturated carboxylic acid represented by the general formula (1) and the general formula (2). Reacting with a cyclic hetero compound in the presence of a polymerization inhibitor and a metal oxide catalyst to obtain α, β represented by the general formula (3).
-A reaction step of obtaining unsaturated carboxylic acid polyheteroalkylene esters. Such a method for producing an α, β-unsaturated carboxylic acid ester may or may not include a step other than the above reaction step. The α, β-unsaturated carboxylic acid esters are α, β-unsaturated carboxylic acid esters.
It is also called an unsaturated carboxylic acid polyheteroalkylene ester.

In the above reaction step, the reaction may be carried out in either a liquid phase or a gas phase. In the present invention, the reaction is preferably carried out in a liquid phase. In particular, when X ¹ is O, when reacted in the gas phase under a metal oxide catalyst, polyalkylene glycols are generated by polymerization of cyclic hetero compounds, so that the catalyst is deactivated or the reactive group is blocked. Therefore, the reaction is preferably performed in a liquid phase.

In the present invention, the α, β-unsaturated carboxylic acid represented by the general formula (1) used as a raw material is
The substituents represented by R ¹ , R ² and R ³ in the formula are not particularly limited as long as they are the same or different, and are compounds composed of a hydrogen atom or an organic residue. In the present specification, an organic residue in a compound represented by the general formula is a group bonded to a basic structure constituting the compound, and is an atomic group essentially including an atom other than a metal atom. Means In addition, examples of the atomic group essentially including an atom other than the metal atom include a hydrocarbon group having 1 to 20 carbon atoms and a group having a nitrogen atom described below.

The organic residue represented by R ¹ , R ² and R ³ is not particularly restricted but includes, for example, linear, branched or cyclic saturated and / or unsaturated alkyl having 1 to 20 carbon atoms. Group, hydroxyalkyl group having 1 to 10 carbon atoms, 1 carbon atom
An alkoxyalkyl group having 10 to 10, a halogenated alkyl group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms,
An acyloxyalkyl group having 1 to 20 carbon atoms, an aryl group which may have a substituent, a carboxyl group, -COO
Examples thereof include a carboxylate group and an amide group represented by R (R represents an organic residue). Among these, a saturated and / or unsaturated alkyl group having 1 to 8 carbon atoms, a carboxyl group, and a carboxylate group are preferably used.

The organic residue represented by R is not particularly limited, and may be, for example, a linear, branched or cyclic saturated and / or unsaturated alkyl group having 1 to 20 carbon atoms, a C 1 to C 10 alkyl group.
A hydroxyalkyl group, an alkoxyalkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms,
An aryl group which may have a substituent is exemplified.
Among these, a saturated and / or unsaturated alkyl group having 1 to 8 carbon atoms is preferably used.

Representative examples of the α, β-unsaturated carboxylic acids represented by the above general formula (1) are not particularly limited, and specific examples thereof include (meth) acrylic acid, maleic acid, and maleic acid monoester. Fumaric acid, fumaric acid monoester, itaconic acid, itaconic acid monoester, methylenemalonic acid, methylenemalonic acid monoester, α-hydroxymethylacrylic acid, α- (1-hydroxyethyl) acrylic acid, α-chloromethylacryl Acid, α- (1-chloroethyl) acrylic acid, α-bromomethylacrylic acid, α
-(1-bromoethyl) acrylic acid, α-acetoxymethylacrylic acid, cinnamic acid, crotonic acid, α-acetamidoacrylic acid, β-ethyl (meth) acrylic acid, β-propyl (meth) acrylic acid, β-methoxy ( (Meth) acrylic acid, β-ethoxy (meth) acrylic acid and the like. These may be used alone or in combination of two or more. Among them, (meth) acrylic acid, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, itaconic acid, itaconic acid monoester, cinnamic acid, crotonic acid and the like are preferably used.

In the present invention, the cyclic hetero compound represented by the general formula (2) used as a raw material is represented by R in the formula
Substituents represented by ⁴ is composed of a hydrogen atom or an organic residue, the substituents represented by X ¹ is O, if the compound consists of S or NH, but is not particularly limited. R ⁴
The organic residue represented by is not particularly limited, for example,
Linear, branched, or cyclic saturated and / or branched carbon having 1 to 10 carbon atoms;
Or an unsaturated alkyl group, a C1-C5 hydroxyalkyl group, a C1-C5 halogenated alkyl group, an aryl group, etc. are mentioned. Among these, a saturated and / or unsaturated alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 1 to 2 carbon atoms, and a halogenated alkyl group having 1 to 2 carbon atoms are preferably used.

The typical examples of the cyclic hetero compounds represented by the above general formula (2) are not particularly limited, and specific examples thereof include ethylene oxide, propylene oxide,
Examples thereof include 2-butylene oxide, 2,3-butylene oxide, epoxybutene, glycidol, epichlorohydrin, epibromohydrin, styrene oxide, ethyleneimine, and ethylene sulfide. These may be used alone or in combination of two or more.
Among these, it is preferable to use ethylene oxide and propylene oxide.

The reaction molar ratio of the α, β-unsaturated carboxylic acid represented by the general formula (1) and the cyclic hetero compound represented by the general formula (2) is not particularly limited. It is determined by the number of moles of the desired cyclic hetero compound. For example, if you want the average number of moles to be 2,
The molar ratio of α, β-unsaturated carboxylic acids / cyclic hetero compounds may be about 1/2.

The α, β-unsaturated carboxylic acid and the cyclic hetero compound may be charged at once in the early stage of the reaction, or one of them may be continuously or intermittently added to the reaction system. Both may be added to the reaction system continuously or intermittently. Among these, the method of batch charging and the method of adding cyclic hetero compounds continuously or intermittently to the reaction system are preferable.

The catalyst used in the above reaction step is a metal oxide catalyst, and the metal oxide is not particularly limited. For example, beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, radium oxide, Examples thereof include chromium oxide, zirconium oxide, iron oxide, and cobalt oxide. These may be used alone or in combination of two or more. Among these metal oxides, it is preferable to use magnesium oxide.

In the present invention, the metal oxide is a composite metal
More preferably, it is used as an oxide. The composite metal acid
The oxide is not particularly limited. For example, magnesium oxide
For example, hydroxides such as alumina hydroxide and magnesium
Calcined product of coprecipitated magnesium hydroxide and metal hydroxide; A
l³⁺, Ga³⁺, Zr⁴⁺, Ti⁴⁺, Si⁴⁺, In³⁺, Tl
³⁺, Co³⁺, Ni³⁺, Sc³⁺, La³⁺, Fe²⁺, F
e³⁺, Cr³⁺, Cu²⁺And Mn²⁺Selected from the group consisting of
Oxides to which at least one or more metal ions have been added
Gnesium fired products; hydrotalcite fired products, etc.
No. These may be used alone or in combination of two or more.
May be used in combination. Among these composite metal oxides,
Mg-Al based composite metal oxides are particularly preferred.

In the above composite metal oxide, (Be, M
g, Ca, Sr, Ba, Ra, Cr, Zr, Fe, C
o) / (Al, Ga, Zr, Ti, Si, In, Tl,
The atomic ratio of Co, Ni, Sc, La, Fe, Cr, Cu, and Mn) is not particularly limited, but may be 0.1 to 5
Is preferable, and the range of 0.5 to 4 is more preferable.
The range of 1-3 is particularly preferred. The above range of the atomic ratio is preferable in terms of the yield. In the calculation of the above atomic ratio, the same atom as the numerator and denominator in the above formula is excluded.

The firing temperature for preparing the above-mentioned composite metal oxide is not particularly limited, but may be 200 to 1
The range of 000 ° C is preferable, the range of 300 to 950 ° C is more preferable, and the range of 400 to 800 ° C is particularly preferable. Further, the firing time is not particularly limited, but is preferably in the range of 30 to 400 minutes, and 30 to 300 minutes.
Minutes is more preferable, and the range of 60 to 250 minutes is particularly preferable. The above-mentioned ranges of the calcination temperature and the calcination time are preferable in terms of activation of the catalyst which affects the yield and retention of the crystal structure.

In the present invention, the metal oxide is preferably a metal oxide surface-modified with a metal hydroxide and / or a metal alkoxide. For example, the surface modification of a metal oxide catalyst or a composite metal oxide catalyst with a metal hydroxide and / or a metal alkoxide as necessary to obtain a modified metal oxide catalyst or a modified composite metal oxide catalyst. Alternatively, such a modified metal oxide catalyst or a modified composite metal oxide catalyst can be used. The metal hydroxide is not particularly limited, and examples thereof include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; and alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide. No. The metal alkoxide is not particularly limited, and examples thereof include alkali metal alkoxides such as sodium methoxide, sodium ethoxide, sodium butoxide, potassium methoxide, potassium ethoxide, and potassium butoxide; calcium methoxide, calcium ethoxide, and calcium butoxide. And alkaline earth metal alkoxides such as magnesium methoxide, magnesium ethoxide and magnesium butoxide. These may be used alone or in combination of two or more. The amount of the metal hydroxide and / or metal alkoxide used for the reforming of the metal oxide catalyst or the composite metal oxide catalyst is set to be 0.1 to 0.1 with respect to the metal oxide catalyst or the composite metal oxide catalyst. The range is preferably 1 to 20% by weight, more preferably 0.5 to 10% by weight, and particularly preferably 1 to 5% by weight.
The range of the amount of the metal hydroxide and / or metal alkoxide used for reforming the metal oxide catalyst or the composite metal oxide catalyst is preferable in terms of yield, productivity, and economy.

In the present invention, the reaction of an α, β-unsaturated carboxylic acid with a cyclic hetero compound in the presence of a catalyst can be carried out, for example, in a batch system or a semi-batch system generally used in this type of reaction. And a reaction method such as a continuous method, but is not particularly limited. For example, when the reaction is performed in a batch system, the reaction is performed by introducing cyclic hetero compounds into α, β-unsaturated carboxylic acids. The cyclic hetero compound may be introduced after dissolving the α, β-unsaturated carboxylic acid in the solvent. When the reaction is performed in a continuous manner, α, β-unsaturated carboxylic acids and cyclic hetero compounds are continuously charged into a tubular or tank-type reactor, and the reaction solution is continuously reacted. It is done by removing it from the vessel.
At this time, the catalyst may be continuously supplied together with the raw material, and may be continuously extracted together with the reaction liquid, or in the case of a tubular reactor, a solid catalyst is used by filling the reactor.
You may use it in what is called a fixed bed format. In the case of a tank-type reactor, the solid catalyst may be used in a so-called fluidized bed type in which the solid catalyst is allowed to flow in the reactor together with the reaction solution.

The catalyst may be in a powder state or a molded state according to a reaction system such as a batch system, a semi-batch system and a continuous system. When molded, silica, alumina,
It may be molded by mixing with silica alumina or the like.

The amount of the catalyst used depends on the type and combination of the α, β-unsaturated carboxylic acid represented by the general formula (1) and the cyclic hetero compound represented by the general formula (2). , 0.00 to the α, β-unsaturated carboxylic acid.
It is preferably in the range of 1 to 25% by weight, and 0.005 to 20%.
% By weight, more preferably 0.01 to 15% by weight.
Is more preferable, and the range of 0.05 to 10% by weight is particularly preferable. The range of the amount of the catalyst used is preferable in terms of yield, productivity and economy.

After completion of the reaction, the above catalyst can be easily separated from the reaction system by a method such as filtration or decantation, and the separated catalyst can be reused as it is in the reaction of the present invention.

In the present invention, the starting material represented by the above general formula (1)
The α, β-unsaturated carboxylic acid represented by the general formula (3), which is a product, and the α, β-unsaturated carboxylic acid polyheteroalkylene ester represented by the general formula (3) are radically polymerizable compounds. React in the presence of inhibitor. Thereby, the radical polymerization of the above-mentioned raw materials and products is suppressed, and the yield is improved. Blowing a molecular oxygen-containing gas, a molecular nitric oxide-containing gas, and a molecular nitrogen dioxide-containing gas into the reaction gas phase and / or liquid phase also has an effect of suppressing polymerization.

The polymerization inhibitor is not particularly limited, but specific examples include the following. These polymerization inhibitors may be used alone or in combination of two or more. Hydroquinone, methoxyhydroquinone, benzoquinone, p-tert-butylcatechol, chloranil, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-tert-butylmethoxyhydroquinone, 2,
Quinone-based polymerization inhibitors such as 5-di-tert-aminohydroquinone.

2,6-di-tert-butylphenol, 2,4-di-tert-butylphenol, 2-t
tert-butyl-4,6-dimethylphenol, 2,6
-Di-tert-butyl-4-methylphenol, 2,
6-di-tert-butyl-4-ethylphenol,
2,4,6-tri-tert-butylphenol, 2,
6-tert-butyl-4-hydroxymethylphenol, 2,6-di-tert-butyl-2-dimethylamino-p-cresol, n-octadecyl-3- (3 ′,
5'-di-tert-butyl-4'-hydroxyphenyl) propionate, 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5-di-tert-
(Butylanilino) -1,3,5-triazine, styrinate phenol, α-tocophenol, 2-tert-
Butyl-6- (3'-tert-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ) Ethyl] -4,6-di-tert-pentylphenyl acrylate, 2,2 ′
-Methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6
-Tert-butylphenol), 2,2'-methylenebis (6-cyclohexyl-4-methylphenol),
2,2′-methylenebis [6- (1-methylcyclohexyl) -p-cresol], 2,2′-ethylidenebis (2,4-di-tert-butylphenol), 2,
2′-butylidenebis (2-tert-butyl-4-methylphenol), 4,4′-methylenebis (2,6-
Di-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 1,6-hexanediolbis [3- (3,5-
Di-tert-butyl- (4-hydroxyphenyl)]
Propionate, triethylene glycol bis [(3-
tert-butyl-5-methyl-4hydroxyphenyl)] propionate, N, N′-bis [3- (3,5
-Di-tert-butyl-4-hydroxyphenyl))
Propionyl] hydrazine, N, N'-bis [3-
(3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionyl] hexamethylenediamine,
2,2-thiobis (4-methyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-
tert-butylphenol), 2,2-thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], bis [2-te
rt-butyl-4-methyl-6- (3-tert-butyl-5-methyl-2-hydroxybenzyl) phenyl]
Terephthalate, 1,1,3-tris (2-methyl-4
-Hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5 -Di-tert-butyl-4-hydroxybenzyl) isocyanurate, tris [2- (3 ', 5'-di-tert-butyl-4'-
Hydroxyhydro-cinamoyloxyl) ethyl] isocyanurate, tris (4-tert-butyl-2,6
-Di-methyl-3-hydroxybenzyl) isocyanurate, tetrakis [methylene-3- (3 ', 5'-di-
tert-butyl-4′-hydroxyphenyl) propionate] methane, calcium-bis (ethyl-3,5
-Di-tert-butyl) -4-hydroxybenzyl phosphate, propyl-3,4,5-trihydroxybenzenecarbonate, octyl-3,4,5-trihydroxybenzenecarbonate, dodecyl-3,4,5
-Trihydroxybenzene carbonate, 2,2'-methylenebis (4-m-ethyl-6-tert-butylphenol), 4,4-methylenebis (2,6-di-te
rt-butylphenol), 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl −2,4
6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis [1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5) -Methylphenyl) propionyloxydiethyl] -2,4,8,10-tetraoxaspiro [5,
5] Alkylphenol polymerization inhibitors such as undecane.

Alkylated diphenylamine, N, N'-
Diphenyl-p-phenylenediamine, 6-ethoxy-
2,2,4-trimethyl-1,2-dihydroquinoline,
N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-1,3-dimethylbutyl-p-
Phenylenediamine, 2,2,4-trimethyl-1,2
Dihydroquinoline polymer, aldol-α-naphthylamine, N-phenyl-β-naphthylamine, N,
N′-di-2-naphthyl-p-phenylenediamine,
Amine polymerization inhibitors such as 4,4'-dioctyldiphenylamine and phenothiazine.

Copper dimethyldithiocarbamate, copper diethyldithiocarbamate, copper dipropyldithiocarbamate, copper dibutyldithiocarbamate, copper ethylenedithiocarbamate, copper tetramethylenedithiocarbamate,
Copper dithiocarbamate polymerization inhibitors such as copper pentamethylenedithiocarbamate, copper hexamethylenedithiocarbamate and copper oxydiethylenedithiocarbamate.

4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,
Piperidine such as 6,6-tetramethylpiperidine, 1,4-dihydroxy-2,2,6,6-tetramethylpiperidine, 1-hydroxy-4-benzilyoxy-2,2,6,6-tetramethylpiperidine System polymerization inhibitor.

2,2,6,6-tetramethylpiperidine-N-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-benzoyloxy-2,2,6, 6-tetramethylpiperidine-N
-N-oxyl-based polymerization inhibitors such as oxyl.

Sulfur, dilauryl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thio Dipropionate,
Tetrakis-methylene-3- (laurylthio) propionate methane, distearyl-3,3'-methyl-3,
3'-thiodipropionate, laurylstearyl-
3,3'-thiodipropionate, bis [2-methyl-
4- (3-n-alkylthiopropionyloxy-5-
tert-butylphenyl] sulfide, β-laurylthiopropionate, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole and the like.

Tris (isodecyl) phosphite, tris (tridecyl) phosphite, phenyldiisooctylphosphite, phenyldiisodecylphosphite, phenyldi (tridecyl) phosphite, diphenylisooctylphosphite, diphenylisodecylphosphite, diphenyltriphenyl Decylphosphite, phosphonic acid [1,1-diphenyl-4,
4'-diylbistetrakis-2,4-bis (1,1-
Dimethylethyl) phenyl] ester, triphenylphosphite, tris (nonylphenyl) phosphite, 4,4′-isopropylidenediphenolalkylphosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (Biphenyl) phosphite, distearylpentaerythritol diphosphite, di (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite Phosphite, tetra (tridecyl) -4,4'-butylidenebis (3-methyl-6-tert-butylphenol) diphosphite, hexa (tridecyl)-
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenyl) butanetriphosphite, 3,5-di-tert-butyl-4-hydroxybenzylphosphate diethyl ester, sodium-
Bis (4-tert-butylphenyl) phosphate, sodium-2,2'-methylene-bis (4,6-
Di-tert-butylphenyl) phosphate, 1,
Phosphorus-based polymerization inhibitors such as 3-bis (diphenoxyphosphonyloxy) benzene;

N-nitrosophenylhydroxyamine aluminum salt, N-nitrosophenylhydroxyamine copper salt, N-nitrosophenylhydroxyamine iron salt, N-nitrosophenylhydroxyamine iron salt
N-nitrosophenylhydroxyamine salt-based polymerization inhibitors such as nitrosophenylhydroxyaminetin salt, N-nitrosophenylhydroxyamine zinc salt and N-nitrosophenylhydroxyamine magnesium salt.

Among these polymerization inhibitors, hydroquinone, methoxyhydroquinone, benzoquinone, p-ter
t-butylcatechol, phenothiazine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1,4-dihydroxy-2,2, 6,6-tetramethylpiperidine, 1-hydroxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 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 is preferably used

The amount of the polymerization inhibitor depends on the kind of the α, β-unsaturated carboxylic acid represented by the general formula (1). .
001 to 5% by weight, preferably 0.005 to 1% by weight,
Particularly preferably, it is added so as to be in the range of 0.01 to 0.1% by weight. The range of the addition amount of the polymerization inhibitor is preferable in terms of suppressing polymerization, in terms of yield, and in terms of productivity and economy.

The reaction temperature is not particularly limited, but is preferably in the range of 0 ° C. to 230 ° C.,
The temperature is more preferably in the range of 0 ° C, particularly preferably in the range of 30 ° C to 180 ° C. The reaction pressure is not particularly limited, and may be normal pressure (atmospheric pressure) or pressurization.
The reaction time may be appropriately set depending on the types and combinations of the α, β-unsaturated carboxylic acids, the cyclic hetero compounds, the catalyst and the organic solvent, the amount used, and the like so that the above reaction is completed.

In the present invention, it is not necessary to use a solvent, but an organic solvent can be used. The organic solvent is not particularly restricted but includes, for example, aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as pentane, hexane, cyclohexane and heptane; ethers such as diethyl ether and diisopropyl ether; chloroform. And halogenated hydrocarbons such as methylene chloride, dichloroethane and chlorobenzene. These may be used alone or in combination of two or more.

The amount of the organic solvent used depends on the combination of the α, β-unsaturated carboxylic acid represented by the general formula (1) and the cyclic hetero compound. 0 to 200% by weight, preferably 0 to 100% by weight based on the total amount of
%, More preferably 0 to 80% by weight, particularly preferably 0 to 70% by weight. The range of the amount of the organic solvent used is preferable in terms of yield, productivity, and economic efficiency.

Further, in the present invention, when the above-mentioned cyclic hetero compound used as a raw material is an alkylene oxide, it is preferable that the reaction in the above-mentioned reaction step is carried out in an oxygen-free atmosphere. When performed in an atmosphere in which oxygen is present, the alkylene oxide is converted in the presence of oxygen,
Under certain conditions, an explosive mixed gas is formed, which may lower the safety of the reaction. On the other hand, in an atmosphere in which oxygen is not present at all, raw materials and products undergo asphyxiation polymerization. Therefore, the reaction is preferably performed in a gas atmosphere containing oxygen as a polymerization inhibitor. In this case, for example, when manufacturing under a mixed gas atmosphere containing a relatively high concentration of oxygen such as air, there is a possibility that an explosive mixed gas may be formed when the alkylene oxide is charged into the reactor. High and very dangerous.

In the reaction step using the above-mentioned alkylene oxide as a raw material, when the reaction is carried out in a mixed gas atmosphere containing a relatively low concentration of oxygen, α, β-unsaturated carboxylic acids and alkylene oxide as raw materials are not included. Since an inert gas such as nitrogen or oxygen, which is a sealing gas (a pressurized sealing gas in a tank or the like in which raw materials are stored or a replacement sealing gas, etc.), is dissolved, the reactor gas is charged every time these raw materials are charged. When the oxygen concentration in the phase fluctuates and the oxygen concentration increases, there is a risk of explosion, and when the oxygen concentration approaches 0 vol%, the possibility of asphyxiation polymerization appears. Further, even during the progress of the reaction, the oxygen concentration in the gas phase of the reactor may fluctuate. Therefore, in producing an α, β-unsaturated carboxylic acid ester by reacting an α, β-unsaturated carboxylic acid with an alkylene oxide, the reaction can be carried out at any stage before, during or after the input of the raw materials. It is preferable to maintain the oxygen concentration in the gas phase in a specific low concentration range. In addition, vol% means volume%, and the volume of the entire gas phase of the reactor is 100 vol%.

In the above reaction step, (1) a mixed gas of oxygen / inert gas and / or an inert gas whose oxygen concentration has been previously adjusted to 0.1 to 8 vol% is used, and Oxygen concentration in the gas phase is 0.1-8v
ol%, (2) the oxygen concentration should be 0.1 to
(3) using a mixed gas of oxygen / inert gas adjusted to 8 vol% and / or an inert gas to maintain the oxygen concentration in the gas phase of the reactor during the reaction at 0.1 to 8 vol%;
Using an oxygen / inert gas mixture gas and / or an inert gas whose oxygen concentration has been adjusted to 0.1 to 8 vol% in advance,
It is preferable to maintain the oxygen concentration in the gas phase of the reactor at 0.1 to 8 vol% from the end of the reaction to the preparation of the next reaction. That is, it is preferable to maintain the oxygen concentration in the gas phase of the reactor at 0.1 to 8 vol% before, during, and after the reaction and before the next reaction. Thereby, formation of an explosive mixed gas can be prevented, and asphyxiation polymerization can be suppressed. Preferably, it is in the range of 0.3 to 7.5 vol%, more preferably
It is in the range of 0.5 to 7.0 vol%.

In the above reaction step, for example, before the introduction of the alkylene oxide, the raw material α, β-unsaturated carboxylic acid is previously charged into the reactor.
Since the above-mentioned sealing gas is dissolved in the unsaturated carboxylic acids, even if the oxygen concentration in the gas phase of the reactor is adjusted to the above range before charging the α, β-unsaturated carboxylic acids, α , Β-unsaturated carboxylic acids may cause the oxygen concentration in the gas phase of the reactor to fluctuate.
Therefore, according to the fluctuation, the oxygen concentration is set to 0.1 to 8 in advance.
The mixture is adjusted by adding a mixed gas of oxygen / inert gas adjusted to vol% and / or an inert gas to the gas phase of the reactor. As a specific oxygen concentration adjustment method, for example, when the oxygen concentration in the reactor gas phase increases, the oxygen concentration is reduced by adding an inert gas, and conversely, the oxygen concentration in the reactor gas phase is increased. When decreasing, the oxygen concentration should be 0.1 to 8 vol% in advance.
The oxygen concentration was increased by adding a mixed gas of oxygen / inert gas adjusted to the above, and the oxygen concentration in the gas phase of the reactor was increased to 0.1 to 8 vol.
Maintain in the 1% range. When adjusting the oxygen concentration, for example, when an inert gas is excessively added, a mixed gas of an oxygen / inert gas whose oxygen concentration is adjusted to 0.1 to 8 vol% in advance is added. In some cases, the oxygen concentration in the gas phase of the reactor may be readjusted in the range of 0.1 to 8 vol%.

In the above reaction step, even during the reaction after the introduction of the alkylene oxide, the above-mentioned sealing gas is dissolved in the introduced alkylene oxide. A case where the oxygen concentration in the phase portion fluctuates may occur. Therefore, the oxygen concentration is set to 0.1 in advance according to the fluctuation.
An oxygen / inert gas mixed gas adjusted to 1 to 8 vol% and / or an inert gas is added to the gas phase of the reactor for adjustment. Specifically, it is the same as the above oxygen concentration adjusting method.

Similarly, in the case where the above reaction step is a continuous reaction, the reaction gas is also affected by the effect of the alkylene oxide continuously supplied to the reactor and the sealing gas dissolved in the α, β-unsaturated carboxylic acids. Since the oxygen concentration in the phase portion fluctuates, the oxygen concentration is set to 0.1 to 8 v in the same manner as described above.
It is useful to keep it in the ol% range. After the reaction is completed, the reaction solution is taken out of the reactor.
Since the internal pressure in the reactor decreases, it may be necessary to suppress the decrease in the internal pressure by gas injection from the outside. When the reaction solution is taken out of the reactor, it may be taken out from the beginning by gas injection from the outside. In these operations, the oxygen concentration in the gas phase of the reactor may fluctuate when gas is injected from the outside. In addition, when the oxygen concentration in the gas injected from the outside is high, if the alkylene oxide remains in the reactor, an explosive gas may be formed, which is extremely dangerous. Therefore, as a gas used in performing the above operation, a mixed gas of oxygen / inert gas whose oxygen concentration is adjusted to 0.1 to 8 vol% in advance and / or an inert gas is used, and Oxygen concentration of 0.1 ~ 8vo
Maintain in the 1% range. Further, the oxygen concentration is set to 0.
Using a mixed gas of oxygen / inert gas adjusted to 1 to 8 vol% and / or an inert gas, after the reaction liquid is taken out and before the next reaction preparation, the gaseous phase of the reactor is removed. If the oxygen concentration is adjusted so as to be maintained in the range of 0.1 to 8 vol%, there is little possibility that an explosive mixed gas is formed with the alkylene oxide remaining in the reactor, and the residual gas in the reactor is reduced. This is effective in that the reactor can be maintained in a safe state without polymerizing the reaction liquid (valve, nozzle portion, etc.).

In the above reaction step, as a specific method for controlling the oxygen concentration in the gas phase of the reactor, oxygen / inert gas and / or inert gas may be continuously supplied, It may be thrown in. These gases also
It may be charged into the gas phase of the reactor or may be blown into the reaction solution. In any case, a dispersion plate or the like may be provided to improve gas dispersion. Further, the pressure in the reactor may be increased by introducing these gases, in which case the gas may be intermittently purged, or if the gas is continuously supplied, the gas may be continuously discharged. The gas may be purged.

The pressure in the reactor in the above reaction step is preferably in the range of 0.05 to 3 MPa, more preferably in the range of 0.1 to 2 MPa, and still more preferably in the range of 0.1 to 1 MPa. Within range. When the pressure in the reactor is lower than 0.05 MPa, the alkylene oxide does not easily exist as a liquid under the reaction temperature condition, and the progress of the reaction is slowed. On the other hand, if it is higher than 3 MPa, a reactor having a high pressure resistance is required, which is not economically preferable. Also, including this purge gas, the alkylene oxide contained in the gas purged from the reactor may be absorbed in water or the like and discarded.However, the alkylene oxide is led to an alkylene oxide recovery facility, and is condensed and recovered by a condenser. Or by absorbing it into a liquid such as a polar solvent such as water, a raw material α, β-unsaturated carboxylic acid, or a product α, β-unsaturated carboxylic acid ester, and recovering it. Is economically preferable. In particular, it is preferable to absorb and recycle the α, β-unsaturated carboxylic acid as a raw material or the α, β-unsaturated carboxylic acid ester as a product and a mixture thereof.

When an α, β-unsaturated carboxylic acid is reacted with an alkylene oxide to produce an α, β-unsaturated carboxylic acid ester, the oxygen concentration in the gas phase of the reactor is reduced to 0 throughout the production process. It can be said that it is a preferable mode to maintain the pressure at 0.1 to 8 vol%. This is because if such a low oxygen concentration can be maintained throughout the manufacturing process, safe and stable manufacturing can be achieved. In general, the above-mentioned production step comprises a reaction step, a separation step of unreacted alkylene oxide, a separation step of unreacted α, β-unsaturated carboxylic acids, and a distillation step of a product. Here, unreacted α, β-
The step of separating unsaturated carboxylic acids includes α, β in the reaction.
-Omitted when the conversion of unsaturated carboxylic acids is close to 100%.

The unreacted alkylene oxide separation step is, for example, separation and removal of the unreacted alkylene oxide from the liquid after the reaction using an inert gas or the like using a packed column.
In this step, the alkylene oxide in the gas is absorbed by a solvent such as water, and the gas is discarded or collected and reused. The step of separating the unreacted α, β-unsaturated carboxylic acids includes, for example, unreacted α, β-unsaturated carboxylic acids by distillation using a distillation still.
-Separation and removal of unsaturated carboxylic acids from the liquid after the reaction, and vapor (distillate) is condensed by a condenser or the like or absorbed in a solvent such as water to be discarded or collected and reused. This is the step of performing The product distillation step is, for example, a step of distilling a product by distillation using a still and condensing the product with a condenser or the like to obtain a product.

In the present invention, when an alkylene oxide is used as a raw material, in addition to the above-mentioned reactor gas-phase part, a gas-phase part in a step of separating unreacted alkylene oxide from a product, that is, in the above example, Gas in the packed tower, gas phase such as the vapor line until the gas introduced from the packed tower is absorbed by a solvent such as water, and gas in the intermediate tank such as the feed tank attached to the packed tower. It is a more preferable embodiment that the oxygen concentration in the phase portion is also maintained at 0.1 to 8 vol%.

In the above embodiment, a more preferable embodiment is a gas phase in the step of separating unreacted α, β-unsaturated carboxylic acids from the product, that is, in the above-mentioned example, a gas phase in the distillation still, and Vapor phase such as vapor line until vapor led from distillation still is condensed by condenser or absorbed by solvent such as water, intermediate tank such as feed tank and distillation tank attached to distillation still And / or the gas phase in the distillation step of the product, that is, in the above-described example, until the gas phase in the distillation pot and the vapor guided from the distillation pot are condensed by a condenser or the like. In this embodiment, the oxygen concentration of the gas phase of the vapor line such as the vapor line, the feed tank attached to the distillation still and the intermediate tank such as the distillation tank is also maintained at 0.1 to 8 vol%.

The equipment used in the step of separating the unreacted alkylene oxide and the unreacted α, β-unsaturated carboxylic acids and the step of distilling the product include a packed column, a tray column, a bubble bell column, and a distillation still. However, it is not particularly limited. The oxygen concentration in the step of separating unreacted alkylene oxide from the product other than the gas phase of the reactor is 0.1 to
By maintaining the content at 8 vol%, the gas in the gas phase is less likely to form an explosive mixed gas with the alkylene oxide, and a polymer is generated in the step of separating unreacted raw materials and the step of distilling the product. Α, β-unsaturated carboxylic esters can be produced safely without the need. A gas having a high oxygen concentration, such as air, is used as an oxygen supply source in place of the oxygen / inert gas mixed gas whose oxygen concentration has been adjusted to 0.1 to 8 vol% in advance and / or the inert gas. Then, even if the oxygen concentration in the entire gas phase of the reactor is in the range of 0.1 to 8 vol%, there is a high possibility that an explosive gas having a high oxygen concentration is locally formed near the air injection nozzle. .

The α, β-unsaturated carboxylic acid polyheteroalkylene esters produced according to the present invention are represented by the above general formula (3), wherein R ¹ , R ² and R ³ are each the same as defined above. This is the same as the definition in Expression (1). R ⁴ and X ¹
Is the same as defined in the above general formula (2). R ⁵ ,
One of R ⁶ , R ⁷ and R ⁸ is R ⁴
And the remaining three represent hydrogen atoms. n1 represents one or more positive numbers.

The α, β-unsaturated carboxylic acid polyheteroalkylene esters produced according to the present invention can be obtained after the above reaction step, if necessary, separately from or in addition to the above steps. By purifying the resulting solution. The purification means is not particularly limited, and can be separated and purified by, for example, a distillation method, an extraction method, and a column chromatography method. These methods may be performed alone or in combination.

The present invention also provides the following general formula (4):

[0064]

Embedded image

[0065] (wherein, R ^9, R ¹⁰ and R ¹¹ are the same or different, .R ¹² represents a hydrogen atom or an organic residue, R
^{One of 13} , R ¹⁴ and R ¹⁵ represents an organic residue, and the remaining three represent a hydrogen atom. X ² is O,
Represents S or NH. n2 represents one or more positive numbers. ), A catalyst for producing an α, β-unsaturated carboxylic acid ester, the catalyst comprising a metal oxide
It is also a catalyst for the production of β-unsaturated carboxylic esters. The catalyst preferably contains a metal oxide as a main component, and may or may not additionally contain other components.

[0066] In the general formula (4) is not particularly restricted but includes organic residues in R ^9, R ¹⁰ and R ^11, for example, is the same as above R ^1, R ² and R ^3, the R ^12,
R ^13, examples of the organic residue constituting any one of R ¹⁴ and R ¹⁵ is not particularly limited, for example, the R ⁴
Is the same as

The metal oxide is not particularly limited.
For example, the above-mentioned metal oxides can be used. Preferred embodiments are (1) an embodiment using the above-mentioned composite metal oxide as the above-mentioned metal oxide, and (2) an above-mentioned metal water as the above-mentioned metal oxide. A form using a metal oxide surface-modified with an oxide and / or a metal alkoxide, and the like can be given.

The catalyst comprising the metal oxide of the present invention is
It can be used for the production of α, β-unsaturated carboxylic acid esters represented by the above general formula (3).
The α, β-unsaturated carboxylic acid represented by the general formula (1) is reacted with the cyclic hetero compound represented by the general formula (2) in the presence of a polymerization inhibitor to form the compound represented by the general formula (1). 3)
Which is preferably used in a method for producing an α, β-unsaturated carboxylic acid ester comprising a reaction step of obtaining an α, β-unsaturated carboxylic acid ester represented by the formula: The catalyst is suitable for economically and efficiently producing the compounds.

[0069]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 (Production of Catalyst A) 25 g of a commercially available magnesium oxide powder (Kyowa Mag 150, manufactured by Kyowa Chemical Industry Co., Ltd.) was placed in a nitrogen stream at 600 g.
The mixture was calcined at 3 ° C. for 3 hours to obtain 22 g of a magnesium oxide catalyst.

Example 2 (Production of Catalyst B) 50 g of commercially available alumina / magnesium hydroxide powder (Kyowa Chemical Industry Co., Ltd .; Kyoward 300) was calcined at 700 ° C. for 3 hours in a nitrogen stream to obtain Mg. 28 g of a -Al-based composite metal oxide catalyst was obtained.

Example 3 (Production of Catalyst C) In a 300 ml beaker, 10 g of the Mg-Al-based composite metal oxide obtained in Example 2 and 200 ml of ethanol were added.
Stirred. Under stirring at room temperature, 14.25 ml of 0.5N potassium hydroxide ethanol solution was added, and stirring was further continued for 2 hours. Thereafter, the solution was filtered, washed with ethanol, and then dried at 50 ° C. under reduced pressure, thereby obtaining 10.4 g of a potassium hydroxide surface-modified Mg—Al-based composite metal oxide catalyst.
I got

Example 4 1 equipped with a thermometer, a stirrer, a pressure gauge, and an inlet tube
After adding 21.6 g of acrylic acid, 11 mg of phenothiazine, 20.9 g of propylene oxide and 1.0 g of catalyst A to a 00 ml Hastelloy C autoclave,
The inside of the autoclave was completely replaced with 2.5 vol% oxygen (nitrogen balance). The mixture was gradually heated with stirring and stirred at an internal temperature of 70 ° C. for 4 hours to complete the reaction. After completion of the reaction, the catalyst was removed from the reaction solution by filtration, and the obtained filtrate was subjected to GC-1700 type gas chromatography (manufactured by Shimadzu Corporation; hereinafter referred to as “G”).
C), the conversion of acrylic acid was 55.8 mol%, the selectivity of 1 mol adduct of propylene oxide was 80.3 mol%, and the selectivity of 2 mol adduct was 18.2 mol. %, And the selectivity of the adduct of 3 mol or more was 1.1 mol%. The diester as a by-product had a selectivity of 0.4 mol%.

Example 5 The same operation as in Example 4 was performed except that the catalyst was changed to 1.0 g of the catalyst B. As a result of measurement by GC, the conversion of acrylic acid was 68.1 mol%, the selectivity of 1 mol adduct of propylene oxide was 86.2 mol%, and the selectivity of 2 mol adduct was 13.2 mol%. The selectivity of the adduct of 3 mol or more was 0.5 mol%. The diester as a by-product had a selectivity of 0.1 mol%.

Example 6 The same operation as in Example 4 was performed except that the catalyst was changed to 1.0 g of the catalyst C. As a result of measurement by GC, the conversion of acrylic acid was 65.6 mol%, the selectivity of 1 mol adduct of propylene oxide was 85.8 mol%, and the selectivity of 2 mol adduct was 13.6 mol%. The selectivity of the adduct of 3 mol or more was 0.5 mol%. The diester as a by-product had a selectivity of 0.1 mol%.

Example 7 After adding 21.6 g of acrylic acid, 11 mg of phenothiazine and 1.0 g of catalyst B to the same apparatus as in Example 4, the inside of the autoclave was completely replaced with 2.5% oxygen (nitrogen balance). Then, ethylene oxide 15.8
g, and gradually heated with mixing and stirring.
The reaction was completed by stirring at 4 ° C. for 4 hours. After completion of the reaction, the result of measurement by GC showed that the conversion of acrylic acid was 90.2 mol%, the selectivity of 1 mol adduct of ethylene oxide was 94.2 mol%, and the selectivity of 2 mol adduct was 5. 1 mol%, and the selectivity of the adduct of 3 mol or more was 0.5 mol%. The diester as a by-product had a selectivity of 0.2 mol%.

Comparative Example 1 The same operation as in Example 4 was performed except that the inside of the reaction vessel was completely replaced with nitrogen instead of 2.5 vol% oxygen (nitrogen balance). As a result, a white polymer was formed after 3 hours, and even stirring was difficult.

Comparative Example 2 The same operation as in Example 4 was carried out except that phenothiazine as a polymerization inhibitor was not added (no polymerization inhibitor was present). As a result, a white polymer was formed after 2 hours, and even stirring was difficult.

[0079]

According to the production method of the present invention, the distribution of the number of added moles of the cyclic hetero compound is sharp, and almost no diester of α, β-unsaturated carboxylic acid is contained in the above general formula (3). The α, β-unsaturated carboxylic acid polyheteroalkylene esters represented can be economically produced with high productivity.

The α, β-unsaturated carboxylic acid polyheteroalkylene esters represented by the above general formula (3) obtained by the present invention can be used as a fragrance, a raw material for medicinal and agricultural chemicals, an organic synthetic intermediate,
Furthermore, it can be widely used for polymerizable materials and the like.

Continued on the front page F term (reference) 4H006 AA02 AA05 AC48 BA06 BA10 BA14 BA19 BA20 BA30 BN10 BP10 4H039 CA66 CF90

Claims (4)

[Claims] 1. The following general formula (1): Wherein R ¹ , R ² and R ³ are the same or different and each represent a hydrogen atom or an organic residue.
-Unsaturated carboxylic acids and the following general formula (2): (Wherein, R ⁴ represents a hydrogen atom or an organic residue. X ¹
Represents O, S or NH. ) Is reacted with a cyclic hetero compound represented by the following general formula (3) in the presence of a polymerization inhibitor and a metal oxide catalyst. (Wherein, R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom or an organic residue. One of R ⁵ , R ⁶ , R ⁷ and R ⁸ is R ⁴ . And the remaining three represent hydrogen atoms; X ¹ represents O, S, or NH; n1 represents a positive number of 1 or more.
-A process for producing .alpha.,. Beta.-unsaturated carboxylic esters, comprising a reaction step for obtaining unsaturated carboxylic esters. 2. The method for producing α, β-unsaturated carboxylic acid esters according to claim 1, wherein the metal oxide is a composite metal oxide. 3. The method according to claim 1, wherein the metal oxide is a metal hydroxide and / or a metal hydroxide.
3. The α, β- according to claim 1 or 2, wherein the metal oxide is a metal oxide surface-modified with a metal alkoxide.
Process for producing unsaturated carboxylic esters. 4. The following general formula (4): (In the formula, R ⁹ , R ¹⁰ and R ¹¹ are the same or different and each represent a hydrogen atom or an organic residue. Any one of R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ is an organic residue. Represents
The remaining three represent hydrogen atoms. X ² is O, S or NH
Represents n2 represents one or more positive numbers. A), a catalyst for producing an α, β-unsaturated carboxylic acid ester, wherein the catalyst is a catalyst containing a metal oxide. Catalyst for the production of esters.