JP4855014B2 - Process for producing α, β-unsaturated carboxylic acid ester and α, β-unsaturated carboxylic acid ester - Google Patents

Description

  The present invention relates to a method for producing an α, β-unsaturated carboxylic acid ester. Specifically, the present invention relates to a method for producing an α, β-unsaturated carboxylic acid ester using a solid acid as a catalyst and the obtained α, β-unsaturated carboxylic acid ester.

Conventionally, as an acid catalyst for producing an α, β-unsaturated carboxylic acid ester by reacting an alcohol with an α, β-unsaturated carboxylic acid or a lower ester thereof, a mineral acid (sulfuric acid, phosphoric acid, etc.) and Sulfonic acid (p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, etc.) is generally used.
However, when these Bronsted acids are used as catalysts, a complicated catalyst removal step such as neutralization, water washing or adsorption treatment is required after the reaction, and a large amount of waste is generated and obtained. There is a problem that a catalyst residue remains in the carboxylic acid ester and corrodes the metal in contact depending on its use.
In order to solve these problems, methods for producing α, β-unsaturated carboxylic acid esters using various solid acid catalysts have been proposed. By using a solid acid that is a heterogeneous catalyst, the reaction product and the catalyst can be easily separated, and the generation of waste due to neutralization, washing with water and the like is suppressed.
As these solid acid catalysts, those using an ion exchange resin (sulfonated styrene-divinylbenzene copolymer) as a catalyst (Patent Documents 1 and 2), a sulfonic acid-containing fluororesin (Du-Pont "Nafion", etc.) ) Have been proposed (Patent Document 3), and those using a solid superacid such as phosphotungstic acid as a catalyst (Patent Document 4).
However, none of these solid acid catalysts have satisfactory catalytic activity as a catalyst for α, β-unsaturated carboxylic acid esters, and by-products are easily generated. By-products include elimination reaction products (olefins produced by elimination of water from one molecule of alcohol), etherification products (ethers produced by dehydration condensation from two molecules of alcohol) and addition products (α, There is an adduct formed by adding alcohol to a β-unsaturated group), and there is a problem that the purity of the obtained α, β-unsaturated carboxylic acid ester is low.
In addition, although less than in the case of Bronsted acid, there is also a problem that acid components such as sulfur oxides eluted by decomposition of the catalyst are likely to remain.
Japanese Patent Application Laid-Open No. 64-9956 Japanese Patent Laid-Open No. 10-81647 JP 11-319574 A JP-A-11-152248

  An object of the present invention is a method for producing a high-purity α, β-unsaturated carboxylic acid ester, which does not generate a large amount of waste, has few by-products and catalyst residues, and is obtained by the production method. Another object is to provide an α, β-unsaturated carboxylic acid ester.

  The present inventors diligently studied to solve the above problem and arrived at the present invention. That is, the present invention is characterized by reacting an alcohol (A) with an α, β-unsaturated carboxylic acid or a lower alkyl ester (B) thereof in the presence of the sulfonic acid group-supporting inorganic porous material (α). a process for producing an α, β-unsaturated carboxylic acid ester; and an alcohol (A) and an α, β-unsaturated carboxylic acid or a lower alkyl ester thereof (B) in the presence of the sulfonic acid group-supporting inorganic porous material (α); ), The sulfur atom content is 50 ppm or less based on the weight of the α, β-unsaturated carboxylic acid ester, and the by-product ether compound and by-product addition product are α, β-unsaturated carboxylic acid. An α, β-unsaturated carboxylic acid ester that is 2 mol% or less and 1 mol% or less, respectively, based on the number of moles of ester.

  The method for producing an α, β-unsaturated carboxylic acid ester of the present invention can produce a high-purity α, β-unsaturated carboxylic acid ester with few by-products and catalyst residues.

  In the present invention, the alcohol (A) (hereinafter sometimes simply referred to as (A)) includes a monohydric alcohol (A1) and a dihydric or higher polyhydric alcohol (A2).

Examples of (A1) include the following.
(A11) Saturated aliphatic monohydric alcohol [C1-C36 linear or branched alcohol such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, butyl alcohol, 2-ethylhexyl alcohol, octyl alcohol, nonyl Alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, nonadecyl alcohol, 2-decyl tetradecyl alcohol, 2-tetradecyl octadecyl alcohol, etc.];
(A12) Unsaturated aliphatic monohydric alcohol [C2-C36 linear or branched alcohol such as vinyl alcohol, (meth) allyl alcohol, octenyl alcohol, decenyl alcohol, dodecenyl alcohol, tride Senyl alcohol, pentadecenyl alcohol, oleyl alcohol, gadreyl alcohol, linoleyl alcohol, etc.];
(A13) Alicyclic monohydric alcohol [alcohol having 6 to 36 carbon atoms having an alicyclic group, such as ethyl cyclohexyl alcohol, propyl cyclohexyl alcohol, octyl cyclohexyl alcohol, nonyl cyclohexyl alcohol, adamantyl alcohol, etc.];
(A14) Monohydric phenols [phenols having a phenol ring and having 6 to 36 carbon atoms in total, such as phenol, cresol, t-butylphenol, styrenated phenol, bromophenol, etc.];
(A15) a monovalent alcohol having a nitrogen atom, a sulfur atom and / or a halogen atom [an alcohol in which a part of the above (A11) to (A14) is substituted with a nitrogen atom, a sulfur atom and / or a halogen atom-containing group, such as Dimethylaminoethanol, diethylaminoethanol, morpholinoethanol, 2-chloroethanol, etc.];
(A16) Alkylene oxide (hereinafter abbreviated as AO) of the alcohols (A11) to (A15) [C2-C8 ones such as ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO) ), 1,2- or 2,3-butylene oxide, tetrahydrofuran, styrene oxide, etc.] adducts (addition moles 1-50);
Is mentioned.

As a specific example of (A2),
(A21) Dihydric alcohol [C2-C12 alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, etc.), polymerization Polyalkylene glycols having a degree of 2 to 1,000 (such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polybutylene glycol), alicyclic diols (total carbon number having alicyclic groups of 6 to 36) Diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A), and AO adducts of these dihydric alcohols (addition mole number 1 to 50) and bisphenols (bisphenol A, bisphenol) And AO adducts of bisphenol S, etc.) (addition molar number 2 to 30) (AO is the same as above)];
(A22) 3 to 8 or more aliphatic polyhydric alcohol [alkane polyol and its intramolecular or intermolecular dehydrate (glycerin, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, polyglycerin, and dipentaerythritol) , Sugars and derivatives thereof (such as sucrose and methyl glucoside), and AO adducts of the above aliphatic polyhydric alcohols (addition mole number 1 to 50)];
(A23) 3 to 8 or more valent aromatic ring-containing polyhydric alcohol [AO adducts of trisphenols (such as trisphenol PA) (addition mole number 2 to 50), novolak resins (such as phenol novolac and cresol novolac) AO adduct (number of added moles 2 to 50, etc.)].

Of these, (A) is preferably a monohydric alcohol (A1) or a divalent to octavalent polyhydric alcohol and an AO adduct thereof, and more preferably (A1).
Preferred among (A1) are (A11), (A12), (A15) and their AO adducts, and particularly preferred is (A11) from the viewpoint that a highly pure product is easily obtained. Of C8-32 saturated aliphatic monohydric alcohols and AO (especially EO) adducts thereof.
Moreover, although the primary hydroxyl group and the secondary hydroxyl group are mentioned as a hydroxyl group contained in (A), A primary hydroxyl group is preferable.

The α, β-unsaturated carboxylic acid (B1) in the α, β-unsaturated carboxylic acid or lower alkyl ester (B) (hereinafter sometimes simply referred to as (B)) in the present invention is an aliphatic group. Examples include α, β-unsaturated monocarboxylic acids [such as (meth) acrylic acid and crotonic acid] and aliphatic α, β-unsaturated dicarboxylic acids (such as maleic acid, fumaric acid, itaconic acid, citraconic acid).
As the lower alkyl ester (B2) of α, β-unsaturated carboxylic acid, esters (methyl ester, ethyl ester, isopropyl ester, etc.) obtained from (B1) and an alcohol having an alkyl group having 1 to 4 carbon atoms are included. Can be mentioned.

  Among (B), preferred is (B1) from the viewpoint that a highly pure ester is obtained, and more preferred is aliphatic α, β- from the viewpoint that the amount of addition products of by-products is small. Unsaturated monocarboxylic acids, particularly preferred are acrylic acid and methacrylic acid from the viewpoint of excellent polymerizability of the obtained α, β-unsaturated carboxylic acid ester.

The sulfonic acid group-supporting inorganic porous material (α) in the present invention (hereinafter sometimes simply referred to as (α)) is obtained by immobilizing and supporting a sulfonic acid group-containing compound on an inorganic porous material, A catalyst for the esterification reaction of A) and (B).
As the inorganic porous body, a known inorganic porous body can be used, and examples thereof include an inorganic porous body made of one or more inorganic substances selected from the group consisting of silica, alumina, titania, magnesia and zirconia.
Specifically, silica gel as an inorganic porous material made of silica; alumina gel or the like as an inorganic porous material made of alumina; zeolite or the like as an inorganic porous material made of silica and alumina; and as an adsorbent as another inorganic porous material. And “Kyoward” (manufactured by Kyowa Chemical Co., Ltd.) and diatomaceous earth. Of these, silica, alumina, zeolite and “Kyward” are preferable from the viewpoint of catalytic activity, and silica gel and “Kyward” are particularly preferable.

The inorganic porous material is usually a granular material, and examples of the shape thereof include irregular particles, spherical particles, and pellets.
Of these, spherical particles and pellets, particularly spherical particles, are preferred in that the pressure loss when they are reacted by the flow method described later is small.

  The particle diameter of the inorganic porous material is preferably 1 to 8,000 μm, more preferably 10 to 6,000 μm, and particularly preferably 40 to 500 μm as d50 (average particle diameter). When the thickness is 1 μm or more, handling becomes easy, and 8,000 μm or less is preferable in terms of catalytic activity. In the present invention, d50 can be measured by a particle size distribution measuring method defined in JIS K1150.

The specific surface area of the inorganic porous material is, as a BET specific surface area is preferably 30 m ² / g or more, more preferably 50~1,500m ² / g, particularly preferably 100~800m ² / g. It is preferable that it is 30 m ² / g or more in that the catalytic activity is high and the side reaction is reduced. In the present invention, the BET specific surface area can be measured by a specific surface area measurement method defined in JIS K1150.

The aspect ratio of the inorganic porous material is preferably 1.0 to 1.25, more preferably 1.0 to 1.18, and particularly preferably 1.0 to 1.11. The aspect ratio is the ratio of the longest diameter to the shortest diameter of the particles. If the aspect ratio is 1.25 or less, it is preferable in that the pressure loss when the reaction is performed by a flow method described later is small.
In the present invention, the aspect ratio can be measured by observing particles under a microscope, measuring the longest diameter and the shortest diameter, and averaging over 100 particles.

  As a method for supporting the sulfonic acid group on the inorganic porous material, the sulfonic acid precursor group-containing compound (s) that can be converted into a sulfonic acid group (hereinafter sometimes simply referred to as (s)). And a method of converting the sulfonic acid precursor group into a sulfonic acid group.

(S) is a compound having in its molecule a group that reacts with a functional group on the surface of the inorganic porous material and a group that can be converted into a sulfonic acid group.
Examples of the functional group on the surface of the inorganic porous material include a hydroxyl group, an amino group, and a carboxyl group. Preferred is a hydroxyl group from the viewpoint of easily modifying the surface of the inorganic porous material.

On the other hand, the group that reacts with the functional group on the surface of the inorganic porous material contained in (s) includes trialkoxysilyl group, glycidyl group, carboxyl group and the like when the functional group on the surface is a hydroxyl group or an amino group. When the functional group on the surface is a carboxyl group, a trialkoxysilyl group, a glycidyl group, an amino group and the like can be mentioned.
Of these, a trialkoxysilyl group and a glycidyl group, particularly a trialkoxysilyl group, are preferred from the viewpoint that the reaction with the functional group on the surface easily proceeds.
Examples of the sulfonic acid precursor group that can be converted to the sulfonic acid group contained in (s) include a mercapto group (oxidized to convert to a sulfonic acid group) and a phenyl group (sulfonated to convert to a sulfophenyl group). .

  Specific examples of (s) include mercapto group-containing silane coupling agents (such as mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane), phenyl group-containing silane coupling agents (phenyltrimethoxysilane, phenyltriethoxysilane, diphenyl). Dimethoxysilane) and phenyl group-containing glycidyl compounds (phenyl glycidyl ether, nonylphenyl glycidyl ether, etc.). Among these, a mercapto group-containing silane coupling agent is preferable.

The reaction between the silane coupling agent and the inorganic porous material can be performed under various reaction conditions. For example, a silane coupling agent is charged in a proportion of 30 to 60% by weight based on the weight of the inorganic porous material, heated and stirred in the presence of a solvent, the trialkoxysilyl group in the silane coupling agent and the surface of the inorganic porous material It can be obtained by purifying after reacting the functional group (such as a hydroxyl group).
As the reaction solvent, an organic solvent (toluene, xylene, ethyl acetate, methyl ethyl ketone, acetone and / or lower alcohol, etc.) can be used, and a mixed solvent of water and these organic solvents may be used.
Water is preferably used in a small amount in order to promote the activity of the hydroxyl group on the surface of the inorganic porous material and the silane coupling agent, and the ratio of water is particularly preferably 3 times mol or less with respect to the silane coupling agent.
Moreover, the usage-amount of a reaction solvent is 80 to 300% normally based on the weight of an inorganic porous body (in the following,% represents weight% unless there is particular limitation), Preferably it is 100 to 250%.

The reaction temperature is usually 60 to 150 ° C., and the reaction may be performed while removing the alkoxy group-derived substance to be produced (for example, lower alcohols such as methanol and ethanol).
After the reaction, the particulate matter is separated and collected by filtration or using a centrifugal separator, etc., washed with the above organic solvent several times to remove unreacted substances (such as unreacted silane coupling agent), and then dried under reduced pressure. (Normally 100 to 120 ° C., 10 to 20 mmHg for 3 to 5 hours).

  In order to convert a mercapto group into a sulfonic acid group after reacting the mercapto group-containing silane coupling agent, an oxidation reaction is performed in the presence of a reaction solvent. Examples of the oxidizing agent to be used include various oxidizing agents such as nitric acid, hydrogen peroxide, hypochlorite, potassium permanganate, chromic acid or peroxide, with hydrogen peroxide being preferred. As the reaction solvent, acetone, lower alcohol, acetonitrile, pyridine, chloroform and / or dichloromethane are usually used. The reaction temperature is usually 0 to 100 ° C. The oxidation reaction with hydrogen peroxide can also be performed under the reaction conditions described in US Pat. No. 5,912,385.

  In order to sulfonate the phenyl group after reacting the phenyl group-containing silane coupling agent, various sulfonation methods can be applied. Examples of the sulfonating agent include a method using concentrated sulfuric acid, fuming sulfuric acid, sulfur trioxide, chlorosulfuric acid, fluorosulfuric acid or amidosulfuric acid. As a reaction solvent in this case, acetic acid, acetic anhydride, ethyl acetate, acetonitrile, dichloroethane and / or carbon tetrachloride can be used. The reaction temperature is usually −10 to 180 ° C.

  In either case of the oxidation reaction or the sulfonation reaction, the sulfonic acid group-supporting inorganic porous material (α) can be obtained by performing the same operations (separation / recovery, washing and drying) as the purification treatment after the reaction.

  Among the production methods of (α), a method in which a mercapto group-containing silane coupling agent is reacted with an inorganic porous material and then converted to a sulfonic acid group is preferred.

(Α) preferably has an acid value of 5 to 250 mgKOH / g, more preferably 10 to 150 mgKOH / g, and particularly preferably 15 to 100 mgKOH / g.
When the acid value is 5 mgKOH / g or more, the catalytic activity is improved, the esterification reaction proceeds with a small amount of catalyst, and when the acid value is 100 mgKOH / g or less, the side reaction hardly occurs.
The acid value of (α) can be measured by immersing (α) in ion-exchanged water, adding excess sodium hydroxide and stirring, followed by neutralization titration with a 0.1N hydrochloric acid aqueous solution.

(Α) has substantially the same shape as that of the inorganic porous material before supporting the sulfonic acid group, and preferred ranges of d50, BET specific surface area and aspect ratio are the same.

  (Α) preferably has a d50 of 1 to 8,000 μm, more preferably 10 to 6,000 μm, particularly preferably 40 to 500 μm. When it is 1 μm or more, handling becomes easy, and when it is 8,000 μm or less, it is preferable in terms of catalytic activity.

(Α) preferably has a BET specific surface area of 30 m ² / g or more, more preferably 50 to 1,500 m ² / g, particularly preferably 100 to 800 m ² / g. It is preferable that it is 30 m ² / g or more in that the catalytic activity is high and the side reaction is reduced.

(Α) is preferably spherical particles having an aspect ratio of 1.0 to 1.25, more preferably 1.0 to 1.18, and particularly preferably 1.0 to 1.11.
If the aspect ratio is 1.25 or less, it is preferable in that the pressure loss when the reaction is performed by a flow method described later is small.

In the method for producing an unsaturated carboxylic acid ester of the present invention, the charge equivalent ratio of (A) and (B) is usually 1: 3 to 3: 1, preferably 1: 2 to 2: 1, and more preferably 1: It is 1.5 to 1.5: 1, particularly preferably 1: 1.5 to 1: 1.02.
From the viewpoint of improving the reaction rate, it is advantageous to use an excess of (A) or (B) that is easy to remove and to remove excess (A) or (B) after completion of the reaction.

In the method for producing an unsaturated carboxylic acid ester of the present invention, a polymerization inhibitor may be added for the purpose of preventing polymerization of unsaturated groups.
As polymerization inhibitors, phenol polymerization inhibitors (hydroquinone, hydroquinone monomethyl ether, catechol, cresol, di-t-butylcresol, di-t-butylphenol, tri-t-butylphenol, etc.), and amine polymerization inhibitors ( Phenothiazine, diphenylamine, alkylated diphenylamine, etc.).
Of these, preferred are phenol polymerization inhibitors.
The addition amount of the polymerization inhibitor is usually 0.001 to 2%, preferably 0.01 to 1%, more preferably 0.01 to 0.5%, based on the total weight of (A) and (B). Especially preferably, it is 0.01 to 0.2%.

The amount of (α) used is usually 0.1 to 70%, preferably 1 to 60%, more preferably 2 to 50%, particularly preferably 3 to 40% based on the total weight of (A) and (B). %.
By using 0.1% or more, the esterification reaction proceeds efficiently, and 70% or less is preferable from the economical aspect.
Moreover, the ratio of the equivalent amount of the sulfonic acid group in (α) to the charged equivalent of (A) is preferably 0.005 to 0.3, more preferably 0.01 to 0.2. Is the amount added. If it is 0.005 or more, it is preferable from the viewpoint of the reaction rate, and if it is 0.3 or less, it is preferable from the viewpoint that side reactions are suppressed.

  The form of the esterification reaction can be carried out by either a batch method or a flow method.

  In the case of a batch method, (α), (A), (B) and, if necessary, a reaction solvent are charged into a reaction vessel, heated and stirred, and the reaction is allowed to proceed while removing generated water or lower alcohol. After completion of the reaction, the reaction product and (α) are separated by decantation, filtration, centrifugation and the like. When (A) or (B) is used in excess, an unsaturated carboxylic acid ester can be obtained by removing excess raw material before or after separating (α).

The esterification reaction temperature is usually 60 to 180 ° C, preferably 80 to 160 ° C, and more preferably 100 to 140 ° C. 60 degreeC or more is preferable from a viewpoint of reaction rate, and 180 degrees C or less is preferable from a viewpoint of suppressing a side reaction.
The reaction time is usually 10 minutes to 24 hours, preferably 30 minutes to 10 hours, particularly preferably 1 to 5 hours.
As the reaction solvent, hydrocarbon solvents (such as aromatic hydrocarbons such as toluene and xylene), ketone solvents (such as methyl ethyl ketone and methyl isobutyl ketone), and ether solvents (such as tetrahydrofuran) can be used. Of these reaction solvents, hydrocarbon solvents are preferred from the viewpoint that the reaction product water can be easily separated and removed.
Methods for removing generated water or lower alcohol include distillation under normal pressure or reduced pressure, separation or centrifugation, contact with a dehydrating agent such as molecular sieves or magnesium sulfate, water separation membrane, etc. And a membrane separation method using a selective membrane. In the case of the batch method, a method of distilling off under normal pressure or reduced pressure is preferable.

In the case of the flow method, the esterification reaction may be carried out by passing a mixture of (A) and (B) adjusted to a predetermined temperature through a column, fixed bed or fluidized bed packed with (α). it can.
Although an unsaturated carboxylic acid ester can be obtained by distilling the reaction mixture after one pass, (A) and (B) in the presence of (α) from the viewpoint that the reaction rate can be increased. A production method comprising the step (1) of reacting with (2) and the step (2) of removing water or lower alcohol produced by the reaction of (A) and (B) from the reaction mixture is preferred.
In particular, the reaction rate can be further increased by repeating step (1) and step (2). The temperature of the mixture of (A) and (B) that is passed in step (1) is usually 60 to 180 ° C, preferably 80 to 160 ° C, more preferably 100 to 140 ° C. 60 degreeC or more is preferable from a viewpoint of reaction rate, and 180 degrees C or less is preferable from a viewpoint of suppressing a side reaction.
In the step (1), the average liquid passing time per pass (average contact time between the catalyst and the reaction liquid) is usually 0.1 to 60 minutes, preferably 0.2 to 10 minutes, and more preferably 0.5 to 5 Minutes.
As a method of removing water or lower alcohol in the step (2), a method of distilling with a continuous evaporator, a method of distilling under a normal pressure or a reduced pressure using a reaction vessel equipped with a condenser, and a water separation membrane And a method of dehydrating by centrifugation or a dehydrating agent. Among these, a continuous evaporator, a reaction tank with a condenser, and a combination thereof are preferable from the viewpoint of production efficiency.
The number of repetitions of step (1) and step (2) is usually 1 to 500 times, preferably 3 to 200 times, more preferably 5 to 100 times.

  In the production method of the present invention, oxygen can be dissolved in the reaction solution for the purpose of inhibiting the polymerization of (B) and the product. Examples of the oxygen supply source include oxygen gas, air, and a mixture of air and nitrogen (hereinafter, may be abbreviated as (mixture)). Dissolved. Among these, from the viewpoint of safety, air and air-fuel mixture, particularly air-fuel mixture are preferable.

The mixing volume ratio of air to nitrogen in the air-fuel mixture is usually 1: 9 to 9: 1, preferably 1: 9 to 5: 5, particularly preferably 2: 8 to 4: 6. Increasing the ratio of air is preferable in that the effect of inhibiting polymerization is increased, and increasing the ratio of nitrogen is preferable in that coloring of the product is reduced.
The aeration amount of air or mixed gas is preferably 1 to 5,000 mL / min, more preferably 20 to 1,000 mL / min, and particularly preferably 30 to 500 mL / min per 1 kg of the sum of (A) and (B). It is.
As a method for ventilating air or air-fuel mixture, in the case of the batch method, a method of constantly venting from the lower part of the reaction vessel during the esterification reaction can be mentioned.
In the case of the flow method, there may be mentioned a method of venting the step (1), the step (2) and the piping in the middle thereof, but the venting in the step (2) is from the viewpoint of coexistence of reaction rate and polymerization inhibition. Particularly preferred.

The purity of the unsaturated carboxylic acid ester of the present invention is usually 95% or more, preferably 98% or more.
Impurities include unreacted alcohols, elimination reaction products (olefins produced by elimination of water from one molecule of alcohol), by-product ether compounds (ethers produced by dehydration condensation from two molecules of alcohol), by-products. Examples thereof include raw addition products (such as adducts formed by addition of alcohol to α, β-unsaturated groups) and sulfur atom-containing compounds (such as sulfur oxides eluted by decomposition of the catalyst). Moreover, although it is not an impurity, the polymerization inhibitor as an additive is contained.

The content of unreacted alcohol is usually 5 mol% or less, preferably 2 mol% or less, based on the number of moles of the α, β-unsaturated carboxylic acid ester.
The content of the elimination reaction product is usually 2 mol% or less, preferably 0.1 mol% (detection limit) or less, based on the number of moles of the α, β-unsaturated carboxylic acid ester.
The content of the by-product ether compound and the by-product addition product is preferably 2 mol% or less (more preferably 1.5 mol% or less) and 1 based on the number of moles of the α, β-unsaturated carboxylic acid ester, respectively. The mol% or less (more preferably 0.8 mol% or less).

  The sulfur atom-containing compound usually has a sulfur atom content (hereinafter abbreviated as S content) of 50 ppm or less, preferably 20 ppm (detection limit) or less, based on the weight of the α, β-unsaturated carboxylic acid ester. .

Examples of the polymerization inhibitor include one or more polymerization inhibitors selected from the group consisting of the aforementioned phenol polymerization inhibitors and amine polymerization inhibitors.
The content of the polymerization inhibitor is 0.001 to 0.2%, preferably 0.01 to 0.06%, based on the weight of the α, β-unsaturated carboxylic acid ester.

The contents of α, β-unsaturated carboxylic acid ester, unreacted alcohol, elimination reaction product, by-product etherification product and by-product addition product are analyzed by measuring H ¹ -NMR of the product. Can be quantified. The S content can be quantified with an ICP measuring device “ICPS-8000” (manufactured by Shimadzu Corporation).

Since the α, β-unsaturated carboxylic acid ester of the present invention has high purity and has a polymerizable unsaturated group, it can be suitably used as a raw material monomer for various polymers.
Polymers obtained by using the α, β-unsaturated carboxylic acid ester of the present invention as one of the monomers are various resins, resin modifiers, adhesive binders, paint vehicles, and viscosity index improvers for lubricating oils. It can be used as a pour point depressant for lubricating oils or various additives.

<Example>
The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. All parts represent parts by weight.

<Example of production of sulfonic acid group-supported inorganic porous material (α)>
Production Example 1
In a reaction vessel equipped with a stirrer, a heating / cooling device, a thermometer and a reflux tube, 200 parts of silica gel (Wakogel C-100: manufactured by Wako Pure Chemical Industries, Ltd.) previously washed with ion-exchanged water and dried, and as a solvent After charging 400 parts of toluene and 10 parts of water, the temperature was raised to 100-110 ° C. Next, 100 parts of 3-mercaptopropyltrimethoxysilane was added, and the mixture was stirred for 8 hours under reflux. Thereafter, 15 parts of water was further added and reacted for 8 hours. The solid content was separated from the reaction mixture by filtration, washed with 400 parts of toluene three times and 400 parts of isopropyl alcohol three times in that order, and then dried under reduced pressure at 120 ° C. for 5 hours to give a silane coupling agent-carrying inorganic porous material 190. Got a part.
150 parts of the silane coupling agent-supporting inorganic porous material, 450 parts of methanol as a solvent, and 150 parts of 30% hydrogen peroxide solution were charged in a reaction vessel similar to the above, and reacted at 70 ° C. for 8 hours under reflux. It was. The solid content was filtered off from the reaction mixture, washed three times with 400 parts of methanol, once with 400 parts of 0.1N sulfuric acid, and three times with 400 parts of ion-exchanged water, and then dried under reduced pressure at 120 ° C. for 5 hours. As a result, 140 parts of a catalyst (α-1) made of a sulfonic acid group-supporting inorganic porous material was obtained. (Α-1) is a structure in which silica gel bears a sulfopropyl group, and its d50 is 230 μm, the BET specific surface area is 222 m ² / g, the acid value is 37 mgKOH / g, and the aspect ratio is 1.89. .

Production Example 2
190 parts of a silane coupling agent-supported inorganic porous material was obtained in the same manner as in Production Example 1, except that 200 parts of phenyltriethoxysilane was used instead of 3-mercaptopropyltrimethoxysilane. 150 parts of the silane coupling agent-supported inorganic porous material and 180 parts of dichloroethane as a solvent are charged into a reaction vessel, and 10 parts of sulfur trioxide is added dropwise over 5 hours at 17 to 23 ° C. under water cooling. Sulfonation was carried out by stirring at 50 ° C. for 3 hours. After adding 4 parts of ion exchanged water to convert unreacted sulfur trioxide into sulfuric acid, the solid content was filtered off from the reaction mixture and washed 3 times with 400 parts of isopropyl alcohol and 3 times with 400 parts of ion exchanged water. The solution was dried under reduced pressure at 120 ° C. for 5 hours to obtain 140 parts of catalyst (α-2). (Α-2) is a structure in which silica gel bears a sulfophenyl group, and its d50 is 230 μm, the BET specific surface area is 215 m ² / g, the acid value is 45 mgKOH / g, and the aspect ratio is 1.82. .

Production Example 3
140 parts of catalyst (α-3) were obtained in the same manner as in Production Example 1, except that 200 parts of silica-alumina porous material (“KYOWARD 700SN”: manufactured by Kyowa Chemical Industry Co., Ltd.) was used as the catalyst support. . (Α-3) is a structure in which silica-alumina bears a sulfopropyl group, and its d50 is 216 μm, the BET specific surface area is 197 m ² / g, the acid value is 85 mgKOH / g, and the aspect ratio is 1.12. there were.

Production Example 4
140 parts of catalyst (α-4) was obtained in the same manner as in Production Example 1, except that 200 parts of alumina (“activated alumina 200” manufactured by Nacalai Tesque Co., Ltd.) was used as the catalyst carrier. (Α-4) has a structure in which alumina bears a sulfopropyl group, and its d50 is 68 μm, the BET specific surface area is 231 m ² / g, the acid value is 52 mgKOH / g, and the aspect ratio is 1.14. .

Production Example 5
140 parts of catalyst (α-5) was obtained in the same manner as in Production Example 1, except that 200 parts of silica gel (CAriACT Q-6 75-500 μm: manufactured by Fuji Silysia Chemical Ltd.) was used as the catalyst carrier. (Α-5) is a structure in which silica gel bears a sulfopropyl group, and its d50 is 220 μm, the BET specific surface area is 287 m ² / g, the acid value is 43 mgKOH / g, and the aspect ratio is 1.02. .

Production Example 6
140 parts of catalyst (α-6) was obtained in the same manner as in Production Example 1 except that 200 parts of silica gel (CALiACT Q-6 45-75 μm: manufactured by Fuji Silysia Chemical Ltd.) was used as the catalyst carrier. (Α-6) has a structure in which silica gel bears a sulfopropyl group, and its d50 is 58 μm, the BET specific surface area is 320 m ² / g, the acid value is 34 mgKOH / g, and the aspect ratio is 1.02. .

<Production of α, β-unsaturated carboxylic acid ester>
Example 1
1,800 parts of lauryl alcohol and 1,100 parts of methacrylic acid were charged in a reaction vessel equipped with a stirrer, a heating / cooling device, a thermometer and a water pipe (molar ratio 1: 1.3), and a catalyst (α- 580 parts of 1) and 0.3 part of hydroquinone as a polymerization inhibitor were added. An esterification reaction was carried out for 2 hours at a reaction temperature of 115 to 125 ° C. while continuously removing generated water from the system through a water separator. Further, the reaction is allowed to proceed at 115 to 125 ° C. for 1 hour under a reduced pressure of 250 to 300 mmHg, and then the excess methacrylic acid is distilled off at 10 to 20 mmHg and 120 to 130 ° C., followed by cooling and removal of the catalyst by decantation. , 2500 parts of unsaturated carboxylic acid ester (E-1) of the present invention was obtained.
As a result of analysis by H ¹ -NMR, (E-1) contains the desired lauryl methacrylate 99.8 mol% and unreacted alcohol 0.2 mol%, and the elimination reaction product, by-product ether Both chemical compounds and by-product addition products were below the detection limit (0.1 mol% or less).
Further, in order to investigate the elution amount of the sulfonic acid group-derived component from the catalyst into the product, the S content was quantified with an ICP measuring device “ICPS-8000” (manufactured by Shimadzu Corporation). It was.

Examples 2-5
The α, β-unsaturated carboxylic acid esters (E-2) and (E-3) of Examples 2 to 5 in the same manner as in Example 1 except that the raw materials shown in Table 1 below were used in the number of parts shown in Table 1. ), (E-4) and (E-5).
The analysis results of the product are shown in Table 2.

Example 6
A mixture of alkyl alcohols having 12 and 13 carbon atoms (“DOBANOL 23”; manufactured by Mitsubishi Chemical Corporation) 5 in a 12 L stainless steel reaction vessel equipped with a stirrer, heating / cooling device, thermometer, gas inlet, condenser and pit 0.7 kg, 3.3 kg of methacrylic acid (molar ratio 1: 1.3) and 1 g of hydroquinone as a polymerization inhibitor were charged, and an air-nitrogen mixture (1: 2) was aerated at 500 ml / min. After raising the reaction temperature to 115 to 125 ° C., the reaction liquid in the reaction tank was continuously supplied to the stainless steel fixed bed filled with 1.8 kg of the catalyst (α-5) at a flow rate of 1.1 L / min with a diaphragm pump. The reaction liquid and the dehydration process are continuously and continuously circulated while circulating the reaction liquid by circulating the reaction liquid and circulating the discharge liquid to the original reaction tank and dehydrating the reaction liquid at 115 to 125 ° C. at normal pressure. It went for 1 hour.
Thereafter, the inside of the reaction vessel was reduced to 250 to 300 mmHg, and the same reaction and dehydration were further performed for 2 hours to complete the esterification reaction. Next, the entire amount of the reaction solution was returned to the reaction vessel, and the excess methacrylic acid was distilled off under conditions of 10 to 20 mmHg and 120 to 130 ° C. to thereby remove the α, β-unsaturated carboxylic acid ester composition (E 7.6 kg of -6) was obtained.
The average residence time of the reaction liquid per pass on the fixed bed was 2.5 minutes.
Further, the number of repetitions of circulation of the total amount of the reaction solution in the esterification reaction was calculated to be about 18 times from the flow rate in the fixed bed.
The analysis results of the product are shown in Table 2.

Example 7
The α, β-unsaturated carboxylic acid of Example 7 was the same as Example 6 except that the flow rate of the liquid was 3.1 L / min and the average residence time per pass in the fixed bed was 0.8 minutes. An acid ester composition (E-7) was produced.
The number of circulation cycles of the total amount of the reaction solution at normal pressure was calculated to be about 50 times from the flow rate and average residence time in the fixed bed.
The analysis results of the product are shown in Table 2.

Comparative Example 1
The α, β-unsaturation of Comparative Example 1 was conducted in the same manner as in Example 1 except that polystyrene sulfonate type ion exchange resin “Amberlyst-16” (Rohm & Haas) was used as the catalyst. Carboxylic acid ester (H-1) was produced. “Amberlyst 16” had a d50 of 720 μm, a BET specific surface area of 35 m ² / g, an acid value of 280 mgKOH / g, and an aspect ratio of 1.05.
The analysis results of the product are shown in Table 2.

Comparative Example 2
The α, β-unsaturated carboxylic acid ester (H-2) of Comparative Example 2 was produced in the same manner as in Comparative Example 1 except that acrylic acid was used in the number of parts shown in Table 1 as (B).
The analysis results of the product are shown in Table 2.

Comparative Example 3
By esterifying in the same manner as in Example 1 except that sulfuric acid was used as a catalyst in the number of parts shown in Table 1, neutralized and separated with an aqueous sodium hydroxide solution, washed with water and separated with ion-exchanged water. The α, β-unsaturated carboxylic acid ester (H-3) of Comparative Example 3 was obtained.
The analysis results of the product are shown in Table 2.

  As can be seen from Table 2, the α, β-unsaturated carboxylic acid ester of the present invention has few by-products and high purity, and also has a small amount of catalyst residue.

Since the α, β-unsaturated carboxylic acid ester of the present invention has high purity and has a polymerizable unsaturated group, it can be suitably used as a raw material monomer for various polymers.
Polymers obtained by using the α, β-unsaturated carboxylic acid ester of the present invention as one of the monomers are various resins, resin modifiers, adhesive binders, paint vehicles, and viscosity indices for lubricating oils. It can be used as an improver, a pour point depressant for lubricating oil, or various additives.

Claims (10)

In the presence of the sulfonic acid group-supporting inorganic porous material (α), the alcohol (A) is reacted with an α, β-unsaturated carboxylic acid or an alkyl ester (B) having 1 to 4 carbon atoms thereof. A method for producing an α, β-unsaturated carboxylic acid ester, wherein (α) is an inorganic porous material
Reacting with a sulfonic acid precursor group-containing compound (s) to form a sulfonic acid precursor group-supporting inorganic porous material
After the sulfonic acid precursor group is converted into a sulfonic acid group,
A method for producing an α, β-unsaturated carboxylic acid ester which is a porous body . The method for producing an α, β-unsaturated carboxylic acid ester according to claim 1, wherein (A) is a monohydric alcohol, a bivalent to octavalent polyhydric alcohol or an alkylene oxide adduct thereof. The method for producing an α, β-unsaturated carboxylic acid ester according to claim 1 or 2, wherein (B) is acrylic acid or methacrylic acid. (Α) is a granular material in which a sulfonic acid group is supported on an inorganic porous material made of one or more inorganic materials selected from the group consisting of silica, alumina, titania, magnesia and zirconia. The manufacturing method of the alpha, beta-unsaturated carboxylic acid ester of description. The method for producing an α, β-unsaturated carboxylic acid ester according to any one of claims 1 to 4 , wherein (α) is a granular material having an average particle size of 1 to 8,000 µm. The method for producing an α, β-unsaturated carboxylic acid ester according to any one of claims 1 to 5 , wherein (α) has a BET specific surface area of 30 m ² / g or more. (Alpha) in any one of Claims 1-6 which has an acid value of 5-250 mgKOH / g.
, Β-Unsaturated carboxylic acid ester production method. The method for producing an α, β-unsaturated carboxylic acid ester according to any one of claims 1 to 7 , wherein (α) is a spherical particle having an aspect ratio of 1.0 to 1.25. Step (1) in which (A) and (B) are reacted in the presence of (α), and water or an alcohol having 1 to 4 carbon atoms produced by the reaction between (A) and (B) from the reaction mixture. The method for producing an α, β-unsaturated carboxylic acid ester according to any one of claims 1 to 8 , which comprises the step (2) of removing. The method for producing an α, β-unsaturated carboxylic acid ester according to claim 9 , wherein in the step (2), air or a mixed gas composed of air and nitrogen is passed through the reaction mixture.