JP7312463B2 - Meta-phenolsulfonic acid resin and its use as a catalyst - Google Patents

Description

The present invention relates to a meta-phenolsulfonic acid-based resin, a method for producing the resin, a catalyst composition containing the resin, and a method for producing a carboxylic acid ester using the catalyst composition.

Conventionally, phenolic resins have been used as fillers and binders for processed products. The present inventors have found that a phenol resin having a sulfonic acid group has high catalytic activity in the esterification reaction between alcohol and carboxylic acid (Non-Patent Documents 1 to 3). By using this catalyst, an ester can be produced from an alcohol and a carboxylic acid with high efficiency.

M. Minakawa, H. Baek, Y. M. A. Yamada, J. Han and Y. Uozumi Direct Dehydrative Esterification of Alcohols and Carboxylic Acids with a Macroporous Polymeric Acid Catalyst Org. Lett. 15, 5798-5801 (2013) Y. -H. Kim, J. Han, B. Y. Jung, H. Baek, Y. M. A. Yamada, Y. Uozumi, and Y. -S. Lee Production of Valuable Esters from Oleic Acid with a Porous Polymeric Acid Catalyst without Water Removal Synlett 27, 29-32 (2016). H. Baek, M. Minakawa, Y. M. A. Yamada, J. Han and Y. Uozumi In-Water and Neat Batch and Continuous-Flow Direct Esterification and Transesterification by a Porous Polymeric Acid CatalystSci. Rep. 6, 25925 (2016)

By the way, catalysts for industrial use are required to have high catalytic activity, to maintain the activity for a long time, and not to significantly decrease the activity even after repeated use (hereinafter, the property of a catalyst that can be used repeatedly is referred to as "reusability"). An object of the present invention is to provide a novel catalyst composition having good catalytic activity and good reusability. Another object of the present invention is to provide a novel phenolsulfonic acid-based resin that can be used in the catalyst composition, and a novel method and reactor using the catalyst composition as a catalyst.

Previously, the decrease in the activity of the catalyst described in Non-Patent Documents 1 to 3 was thought to be due to elimination of the sulfonic acid group, but the specific mechanism of elimination of the sulfonic acid group was not clarified. As a result of various investigations, the present inventors have found that the sulfonic acid group is eliminated during the course of use as a catalyst by the mechanism shown by the following formula.

As a result of further investigation based on this finding, the inventors found that by incorporating a structural unit in which a sulfonic acid group exists in the meta-position with respect to the —OH group of phenol into a phenolsulfonic acid-based resin, it is possible to reduce the detachment of the sulfonic acid group due to the above mechanism while maintaining good catalytic activity, and completed the present invention.

That is, the gist of the present invention is as follows.
[1] A meta-phenolsulfonic acid-based resin containing a structural unit represented by general formula (I).

(Wherein, R ¹ is an electron-withdrawing group and m1 is an integer of 0 to 2.)
[2] The meta-phenolsulfonic acid-based resin according to [1], further comprising a structural unit represented by formula (II).

(Wherein, R ² is an electron-withdrawing group and m2 is an integer of 0 to 2.)
[3] The meta-phenolsulfonic acid-based resin according to [1] or [2], further comprising a structural unit represented by formula (III).

(In the formula, R ³ is a substituent inert to the polymerization reaction, and m3 is an integer of 0 to 3.)
[4] The meta-phenolsulfonic acid-based resin according to any one of [1] to [3], wherein the electron withdrawing group is selected from the group consisting of halogen, halogenated alkyl having 1 to 4 carbon atoms, ester having 1 to 30 carbon atoms, acyl having 1 to 30 carbon atoms, cyano, amide and nitro.
[5] A catalyst composition containing the meta-phenolsulfonic acid resin according to any one of [1] to [4].

[6] The catalyst composition according to [5], which is used for an esterification reaction or a transesterification reaction.
[7] A step of reacting a carboxylic acid and an alcohol in the presence of the catalyst composition according to [6] to effect an esterification reaction;
A method for producing a carboxylic acid ester, comprising:
[8] A step of reacting a carboxylic acid ester and an alcohol in the presence of the catalyst composition according to [6] to effect an ester exchange reaction;
A method for producing a carboxylic acid ester, comprising:
[9] (i) a step of cation-exchanging a metal salt of meta-phenolsulfonic acid or a derivative thereof to prepare meta-phenolsulfonic acid or a derivative thereof;
(ii) reacting meta-phenolsulfonic acid or a derivative thereof with formaldehyde;
A method for producing a meta-phenolsulfonic acid-based resin according to any one of [1] to [4].
[10] a step of reacting a metal salt of meta-phenolsulfonic acid or a derivative thereof with formaldehyde in the presence of an acid catalyst;
A method for producing a meta-phenolsulfonic acid-based resin according to any one of [1] to [4].
[11] (i) a step of reacting a metal salt of meta-phenolsulfonic acid or a derivative thereof with formaldehyde in the presence of a basic catalyst;
(ii) cation exchange of a polymer of a metal salt of meta-phenolsulfonic acid or a derivative thereof and formaldehyde to prepare a polymer of meta-phenolsulfonic acid or a derivative thereof and formaldehyde;
A method for producing a meta-phenolsulfonic acid-based resin according to any one of [1] to [4].
[12] A catalyst composition containing at least one phenolsulfonic acid-based resin obtained by polymerizing at least phenolsulfonic acids and formaldehydes, wherein at least one of the phenolsulfonic acids is a phenolsulfonic acid having a sulfonic acid group at the meta position.
[13] The catalyst composition according to [12], wherein the at least one phenolsulfonic acid-based resin is a phenolic resin obtained by polymerizing n1 mol of the phenolsulfonic acid and n2 mol (where n1<n2) of the formaldehyde.
[14] A reaction apparatus comprising at least a reaction vessel filled with the catalyst composition according to any one of [5], "6", [12] or [13], one or more supply ports for supplying reaction raw materials to the reaction vessel, and one or more outlets for taking out reaction products from the reaction vessel.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a novel catalyst composition, particularly a novel catalyst composition having good both catalytic activity and reusability, and a novel meta-phenolsulfonic acid resin used therefor. Further, according to the present invention, it is possible to provide a novel method and reactor using the catalyst composition as a catalyst.

FIG. 1 shows the results of SEM/EDS observation of the surface of the meta-phenolsulfonic acid resin produced in Example 1. FIG. The upper left shows SEM photographs. The upper right is the EDS spectrum, showing the presence and content of S, O, C. The lower left is an EDS image showing the distribution of S. The center is an EDS image showing the distribution of O. The right is an EDS image showing the distribution of C. 2 is a diagram showing the results of SEM/EDS observation of the surface of the meta-phenolsulfonic acid resin produced in Example 2. FIG. The upper left shows SEM photographs. The upper right is the EDS EDS spectrum, showing the presence and content of S, O, C. The lower left is an EDS image showing the distribution of S. The center is an EDS image showing the distribution of O. The right is an EDS image showing the distribution of C. 3 is a diagram showing the results of SEM/EDS observation of the surface of the meta-phenolsulfonic acid resin produced in Example 3. FIG. The upper left shows SEM photographs. The upper right is the EDS EDS spectrum, showing the presence and content of S, O, C. The lower left is an EDS image showing the distribution of C. The center is an EDS image showing the distribution of O. The right is an EDS image showing the distribution of S. 4 is a diagram showing the results of SEM/EDS observation of the surface of the meta-phenolsulfonic acid-para-phenolsulfonic acid resin produced in Example 4. FIG. The upper left shows SEM photographs. The upper right is the EDS EDS spectrum, showing the presence and content of S, O, C. The lower left is an EDS image showing the distribution of C. The center is an EDS image showing the distribution of O. The right is an EDS image showing the distribution of S. 5 is a diagram showing the results of SEM/EDS observation of the surface of the meta-phenolsulfonic acid-phenol resin produced in Example 5. FIG. The upper left shows SEM photographs. The upper right is the EDS EDS spectrum, showing the presence and content of S, O, C. The lower left is an EDS image showing the distribution of C. The center is an EDS image showing the distribution of O. The right is an EDS image showing the distribution of S. FIG. 6 is a diagram (photograph) showing the results of optical microscope observation of each resin produced in Examples 1 to 5. FIG. Magnification is ×75, scale bar is 0.5 mm. a) is the meta-phenolsulfonic acid resin produced according to Example 1, b) is the meta-phenolsulfonic acid resin produced according to Example 2, c) is the meta-phenolsulfonic acid resin produced according to Example 3, d) is the meta-para-phenolsulfonic acid resin produced according to Example 4, and e) is the meta-phenolsulfonic acid-phenolic resin produced according to Example 5. FIG. 7 is a diagram showing the results of elemental analysis of each resin produced in Examples 1-5. 8 is a diagram showing the FT-IR analysis results of the meta-phenolsulfonic acid resin produced in Example 1. FIG. 9 is a diagram showing the results of FT-IR analysis of the surface of the meta-phenolsulfonic acid resin produced in Example 2. FIG. 10 is a diagram showing the FT-IR analysis results of the meta-phenolsulfonic acid resin produced in Example 3. FIG. 11 is a diagram showing the FT-IR analysis results of the meta-phenolsulfonic acid-para-phenolsulfonic acid resin produced in Example 4. FIG. 12 is a diagram showing the FT-IR analysis results of the meta-phenolsulfonic acid-phenolic resin catalyst produced in Example 5. FIG. 13 is a diagram showing the results of a reuse experiment of a catalyst containing meta-phenolsulfonic acid resin produced according to Example 1. FIG. 14 is a diagram showing the results of a reuse experiment of a catalyst containing meta-phenolsulfonic acid resin produced according to Example 2. FIG. 15 is a diagram showing the results of a reuse experiment of a catalyst containing meta-phenolsulfonic acid resin produced according to Example 3. FIG. FIG. 16 is a diagram showing the results of a reuse experiment of a catalyst containing para-phenolsulfonic acid resin as a comparative example. FIG. 17 is a diagram (photograph) showing one embodiment of a continuous-flow synthesis apparatus.

The terms used in this specification are explained below.
As used herein, "phenolsulfonic acid-based resin" means "resin containing phenolsulfonic acids-formaldehyde polycondensate" unless otherwise specified.
As used herein, "metaphenolsulfonic acid-based resin" means "resin containing metaphenolsulfonic acids-formaldehyde polycondensate" unless otherwise specified.
As used herein, the term "phenolsulfonic acids" is a general term for phenolsulfonic acid, phenolsulfonic acid derivatives (meaning phenols having other substituents together with a sulfonic acid group) and their metal salts (meaning a group of compounds in which a sulfonic acid group forms a salt with a metal ion), unless otherwise specified.
In the present specification, "formaldehyde" means a generic term for formaldehyde, its aqueous solution (for example, formalin), and polymer (including anhydrous trioxane and paraformaldehyde).
As used herein, the term "resin" includes (co)polymers ((co)polymers) obtained by polymerizing monomers, unless otherwise specified.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
TECHNICAL FIELD The present invention relates to a catalyst composition containing at least one phenolsulfonic acid-based resin obtained by polymerizing at least phenolsulfonic acids and formaldehydes. Here, each of the phenolsulfonic acids and formaldehydes may be used alone or in combination of two or more. In the present invention, at least one of the phenolsulfonic acids is a phenolsulfonic acid having a sulfonic acid at the meta position. In the present invention, good catalytic activity and reusability are achieved by incorporating a structural unit in which the sulfonic acid group is present in the meta position with respect to the --OH group into the phenolsulfonic acid-based resin. For example, as compared with a phenolsulfonic acid-based resin in which only a structural unit in which a sulfonic acid group exists at the para-position with respect to an —OH group is incorporated, the catalyst activity is equal to or higher than that of the resin, and the reusability is improved. In the present invention, a phenolsulfonic acid resin obtained by copolymerizing para-phenolsulfonic acids together with meta-phenolsulfonic acids and/or copolymerizing phenols having no sulfonic acid group may be used.

[resin]
One form of the phenolsulfonic acid-based resin that can be used in the present invention is a resin having a structural unit represented by general formula (I) (hereinafter also referred to as "the resin of the present invention"). The structural unit represented by general formula (I) is a structural unit derived from meta-phenolsulfonic acids (ie, meta-phenolsulfonic acid, derivatives thereof, or metal salts thereof) and formaldehydes, as described below.

In the formula, R ¹ is an electron withdrawing group and m1 is an integer of 0-2.

Electron withdrawing groups are groups that withdraw electrons from a substituted group of atoms. In the present invention, the electron withdrawing group can withdraw electrons from phenolsulfonic acid to increase the acidity of phenolsulfonic acid and improve its reactivity. The electron-withdrawing group is not limited as long as it has such action.

Examples of electron-withdrawing groups R ¹ include, but are not limited to, halogens (X) such as fluorine (-F), chlorine (-Cl), bromine (-Br) and iodine (-I), alkyl halides having 1 to 4 carbon atoms, esters having 1 to 30 carbon atoms, acyl having 1 to 30 carbon atoms, cyano (-CN), amide (-CO-NH ₂ ), nitro (-NO ₂ ), and the like. Electron-withdrawing group R ¹ is preferably halogen (X), halogenated alkyl represented by -C _p X _2p+1 , carboxylic acid ester represented by -CO ₂ R ^a , acyl represented by -COR ^a , cyano, amide, nitro (wherein R ^a is each independently a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring-forming atoms, or a substituted or unsubstituted represents an alkyl group having 1 to 30 carbon atoms, and p is an integer of 1 to 4.) and the like. R ^a is more preferably an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group. Here, the alkyl group may be a linear, branched or cyclic alkyl group, preferably a linear or branched alkyl group, more preferably a linear alkyl group. Specifically, the alkyl group having 1 to 8 carbon atoms is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group or the like, and more preferably methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group or tert-butyl group.

The substitution position of the electron-withdrawing group R ¹ on the aromatic ring is not limited, but is usually p-position (4-position) or m-position (5-position), preferably m-position (5-position).

m1 is the number of substitutions of the electron-withdrawing group R ¹ and is an integer of 0 to 2, preferably 0 or 1;

The position at which the structural unit represented by general formula (I) is polymerized with another structural unit represented by general formula (I) is not limited, but is usually o-position (2-position) or p-position (4-position), preferably o-position (2-position).

A resin having a structural unit represented by general formula (I) may be crosslinked with another structural unit, and the crosslinked position is usually m-position (5-position). By having a crosslinked structure of structural units, the resin of the present invention has a three-dimensional mesh structure.

The ratio of the structural unit represented by general formula (I) to the total 100 mol% of all structural units of the resin having the structural unit represented by general formula (I) is usually 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, 99 mol% or more, and 100 mol%. Moreover, it is usually 99 mol% or less, 95 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, and 50 mol% or less.

The structural unit represented by general formula (I) contained in the resin may be of one type, or may be of two or more types having different structures. When two or more types are included, the above ratio refers to the total of two or more types. This point also applies to various contents and ratios in the present invention and this specification.

Another aspect of the present invention is a resin having a structural unit represented by general formula (I) and a structural unit represented by formula (II).

In the formula, R ² is an electron withdrawing group and m2 is an integer of 0-2.

Specific examples of the electron-withdrawing group R ² , the substitution position on the aromatic ring, and the number of substitutions are the same as those of the electron-withdrawing group R ¹ described in general formula (I).

The ratio of all the structural units of the resin having the structural unit represented by the general formula (I) and the structural unit represented by the formula (II) in the total 100 mol% can be appropriately changed depending on the desired resin performance and the like, and is not limited.

The structural unit represented by general formula (II) contained in the resin may be of one type, or may be of two or more types having different structures.

Another aspect of the present invention is a resin having a structural unit represented by general formula (I) and a structural unit represented by formula (III). Further, another aspect of the present invention is a resin having a structural unit represented by general formula (I), a structural unit represented by general formula (II), and a structural unit represented by formula (III).

In the formula, ^R3 is a substituent inert to the polymerization reaction, and m3 is an integer of 0-3.

The substituent R ³ that is inert to the polymerization reaction is not particularly limited as long as it is a substituent that is inert to the reaction, and examples thereof independently include halogens such as fluorine, chlorine, bromine, and iodine, hydrocarbons having 1 to 30 carbon atoms, acyl having 1 to 30 carbon atoms, cyano, and the like. R ³ is more preferably an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group. Here, the alkyl group may be a linear, branched or cyclic alkyl group, preferably a linear or branched alkyl group, more preferably a linear alkyl group. Specifically, the alkyl group having 1 to 8 carbon atoms is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group or the like, and more preferably methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group or tert-butyl group. The number of substituents R ³ on the aromatic ring may be 1 to 3, preferably 1. The substitution position of the substituent ^R3 on the aromatic ring is not particularly limited.

The ratio of total 100 mol % of the total structural units of the resin with a structural unit represented by the general formula (I) and the structural unit represented by the formula (III) can be changed appropriately according to the performance of the resin, but it is usually 0.1: 99.9 to 99: 0.1 (molar. %), 50: 50-99: 1 (mol %), more preferably 60: 40-90: 10 (mol %).

The structural unit represented by general formula (III) contained in the resin may be of one type, or may be of two or more types having different structures.

The ratio of various structural units represented by general formula (I), formula (II), (III), etc. in the resin can be determined by a known identification method such as NMR. Also, it can be determined from the composition of the compound used in the polymerization of the resin.

The preferred range of the molecular weight of the phenolsulfonic acid-based resin varies depending on the application. Moreover, since it has a three-dimensional network structure and is insoluble in organic solvents, it may be difficult to determine its molecular weight. Generally, the weight average molecular weight is about 2-2 million, 2-10,000, or 200-5,000.

[Resin manufacturing method]
The resin can be synthesized by polymerizing at least phenolsulfonic acids as monomers with formaldehydes. In the present invention, phenolsulfonic acids having a sulfonic acid at the meta position are used as at least one of the phenolsulfonic acids.

<Monomer>
Meta-phenolsulfonic acid can be synthesized, for example, from 3-Aminobenzenesulfonic acid, referring to the literature (Russian Journal of General Chemistry, 2003, 73, 1095-1099). Specifically, the examples described later can be referred to. That is, a meta-phenolsulfonic acid metal salt can be synthesized by substituting a hydroxyl group for the amino group of 3-aminobenzenesulfonic acid. Further, a meta-phenolsulfonic acid derivative can be synthesized from the obtained meta-phenolsulfonic acid or its metal salt by a known synthesis method.
Phenolsulfonic acids (including para-phenolsulfonic acid, para-phenolsulfonic acid derivatives, etc.) other than meta-phenolsulfonic acids, and other monomers (including phenol, phenol derivatives, etc.) are synthesized by known synthesis methods, and commercially available ones can be used.

Phenolsulfonic acids used as monomers may be metal salts (metal salts in which a sulfonic acid group forms a salt with a metal), or may have free sulfonic acid groups. The latter monomer can be prepared, for example, by converting a metal salt into a free sulfonic acid by ion exchange or the like.

Specifically, a method of passing a metal salt solution of phenolsulfonic acid or a derivative thereof through a column packed with a hydrogen-type cation exchange resin can be employed. The cation exchange resin may be either a strongly acidic cation exchange resin or a weakly acidic cation exchange resin, but a strongly acidic cation exchange resin is preferred from the viewpoint of improving the generation rate of sulfonic acid groups. Strongly acidic cation exchange resins include porous type (MR type) cation exchange resins in which a small amount of divinylbenzene is copolymerized with polymerized styrene to form a three-dimensional network structure into which strongly acidic groups such as sulfonic acid groups (—SO ₃ H) are introduced. Examples of strongly acidic cation exchange resins include, but are not limited to, Amberlyst (registered trademark) 16wet (SIGMA-ALDRICH), Diaion (registered trademark) PK series (Mitsubishi Chemical), and the like.

The structures of phenolsulfonic acid or derivatives thereof and metal salts thereof can be confirmed by known analytical methods such as NMR.

Examples of metal salts used as monomers include salts of alkali metals such as sodium, lithium, potassium, rubidium and cesium, and salts of alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium. Among these, alkali metal salts are preferred, and sodium salts are more preferred.

The formaldehyde is not limited as long as it is a source of formaldehyde for polymerizing with phenolsulfonic acids to produce a phenolsulfonic acids-formaldehyde copolymer.
Examples of formaldehydes include formaldehyde, paraformaldehyde, formaldehyde aqueous solution (formalin), and the like. As formaldehydes, those synthesized by known synthesis methods and commercially available ones can be used.

<Polymerization method>
As a method for preparing the resin of the present invention by polymerizing phenolsulfonic acids and formaldehydes, 1) an acid catalyst method using an acid catalyst (Acidic method) and 2) a base catalyst method using a basic catalyst (Basic method) can be used.
Each method is described below.

The acid catalyst used in the 1) acid catalyst method is not particularly limited and can be appropriately selected depending on the purpose. Examples of the acid catalyst include inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, organic acids such as oxalic acid, acetic acid, citric acid, tartaric acid, benzoic acid, and p-toluenesulfonic acid, and organic acid salts such as zinc acetate and zinc borate, which are commonly used in the synthesis of phenolic resins. In addition, these acid catalysts may use 1 type, and may use 2 or more types together. Among these, sulfuric acid can be preferably used from the viewpoint of being available at low cost. In addition, in a mode in which the phenolsulfonic acids used as monomers act as an acid catalyst, the polymerization reaction can proceed without adding an acid catalyst separately.

The amount of the acid catalyst to be used is not particularly limited and can be appropriately selected depending on the intended purpose. The molar ratio of the metal salt of phenolsulfonic acid or its derivative to the acid catalyst is usually in the range of 1:0.001 to 1:1, preferably 1:0.01 to 1:0.1. The ratio is preferably 1:0.001 or more from the viewpoint of allowing the reaction to proceed sufficiently, and preferably 1:1 or less from the viewpoint of avoiding acid decomposition and gelation.

The basic catalyst that can be used in the above 2) base catalyst method is not particularly limited and can be appropriately selected according to the purpose. Examples of the basic catalyst that can be used include alkali metal hydroxides, alkaline earth metal hydroxides, primary amines, secondary amines and tertiary amines. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, and the like. Examples of the alkaline earth metal hydroxides include magnesium hydroxide, calcium hydroxide, barium hydroxide and the like. Examples of the primary amine include ammonia and monoethanolamine. Examples of the secondary amine include diethanolamine. Examples of the tertiary amine include trimethylamine, triethylamine, triethanolamine, diazabicycloundecene, and the like. In addition, these basic catalysts may use 1 type, and may use 2 or more types together. Among these, sodium hydroxide can be preferably used from the viewpoint of being available at low cost.

The amount of the basic catalyst to be used is not particularly limited and can be appropriately selected depending on the intended purpose. The molar ratio of the metal salt of phenolsulfonic acid or its derivative to the basic catalyst is usually in the range of 1:0.01 to 1:1, preferably 1:0.1 to 1:0.5. The ratio is preferably 1:0.01 or more from the viewpoint that the reaction can be sufficiently carried out, and preferably 1:1 or less from the viewpoint of suppressing hydrolysis.

Polymerization can be carried out by referring to conventional methods for synthesizing phenolic resins (for example, polymerization of para-phenolsulfonic acid and formaldehyde described in Non-Patent Documents 1 to 3, etc.).
Specifically, a polymerization reaction system is prepared by mixing phenolsulfonic acids, formaldehydes, and optionally other monomers (for example, phenol or a phenol derivative (meaning a phenol having a substituent other than a sulfonic acid group) and/or the acid catalyst or basic catalyst), and if desired, the polymerization reaction is allowed to proceed by heating. In order to improve the reaction efficiency, the polymerization reaction is preferably carried out under stirring with a stirring blade, stirrer, homomixer, or the like.

The solvent for the polymerization reaction system is not particularly limited as long as it does not interfere with the polymerization reaction. Examples thereof include alcohols having 1 to 4 carbon atoms such as water, methanol, ethanol, n-butanol and t-butanol, among which water is preferred. A mixture of these can also be used.

From the viewpoint of obtaining a resin at a high yield, the reaction ratio (molar ratio) between phenolsulfonic acids (in an embodiment in which phenols having no sulfonic acid are also copolymerized, the molar ratio of the phenols is also added) and formaldehydes is usually in the range of 1:0.3 to 1:10, preferably 1:1 to 1:5. One aspect of the resin according to the present invention is an aspect in which the molar amounts n1 and n2 of phenolsulfonic acids (in an aspect in which phenols having no sulfonic acid are also copolymerized, the molar ratio of the phenols is also added) and formaldehydes are n1 ≤ n2. A more preferable aspect is n1<n2. Other aspects are 0.5<n2/n1<5, 1<n2/n1<3, or 1.5<n2/n1<3.

The reaction temperature in the polymerization step is not particularly limited and can be appropriately selected depending on the intended purpose. The reaction temperature is preferably 50° C. or higher from the viewpoint of efficient reaction, and preferably 200° C. or lower from the viewpoint of avoiding decomposition of the resin.

The reaction time of the polymerization step is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5 to 100 hours, more preferably 1 to 72 hours. The reaction time is preferably 0.5 hours or more from the viewpoint of obtaining a resin with a high yield, and preferably 100 hours or less from the viewpoint of obtaining a resin with a sufficient yield.

In the polymerization reaction step, addition reaction and condensation reaction of formaldehydes to phenolsulfonic acids proceed to increase the molecular weight and form a three-dimensional crosslinked structure. Depending on the type of catalyst used, the addition reaction and condensation reaction may proceed in concert at the same time, or may proceed predominantly or subordinately, or precedently or trailingly. For example, by changing the reaction temperature (specifically, changing the reaction temperature to a relatively low temperature of less than 100° C. in the first half and a relatively high temperature of 100° C. or higher in the second half), the polymerization reaction may be adjusted so that either reaction becomes dominant.

After the polymerization reaction, if desired, isolation and purification can be carried out by known isolation and purification methods, for example, general operations such as precipitation, neutralization, filtration and extraction. For example, when the resin obtained by the above polymerization is obtained as a metal salt in which the sulfonic acid group in the structure forms a salt with a metal ion, it is preferable to perform a treatment to convert the sulfonic acid group into a free acid. Examples of such treatments include ion exchange. Ion exchange can be carried out with reference to a conventionally known method. If desired, it may be used as a catalyst after being subjected to a pulverization treatment or the like.

[Use of catalyst composition]
The catalyst composition of the present invention can be used for various reactions. In one embodiment of the catalyst composition of the present invention, the resin used is a solid catalyst having a three-dimensional crosslinked structure, and has excellent chemical resistance, heat resistance, flame retardancy, and mechanical properties (high strength and high degree), and can be used as a catalyst for various reactions. Since the resin has sulfonic acid groups, it is suitable for acid-catalyzed reactions. In addition, since the resin has a hydrophilic sulfonic acid group, it is preferable to use it in a reaction in which water and a hydrophilic substance (such as alcohol) are produced as by-products, because the progress of the reaction does not stagnate even if the by-products are not removed.

One embodiment of the catalyst composition of the present invention is the form utilized in the esterification reaction. Specifically, the above embodiment is a mode in which the catalyst composition of the present invention is used in a reaction for producing a carboxylic acid ester from an alcohol and a carboxylic acid. Carboxylic acid esters are important compounds used in a variety of applications. Carboxylic acid esters are used as emulsifiers, fuels, lubricants, plasticizers, etc., and are also used in the industrial production of alkyl resins. The esterification reaction of carboxylic acids with alcohols is therefore one of the most important chemical transformations in both chemical synthesis and industrial chemistry. This esterification reaction is an equilibrium dehydration reaction with the formation of an equivalent amount of water as a by-product. Conventional esterification methods have required high energy input for the water removal step. By using the catalyst composition of the present invention, it is possible to reduce the energy consumed for water removal work, and to improve productivity.

Another embodiment of the catalyst composition of the present invention is one that is utilized in the transesterification reaction between an alcohol and a carboxylic acid ester. This aspect also provides the same effects as described above.

The catalyst composition of the present invention may contain thickeners, reinforcing materials, additives and the like, if necessary, in addition to the above resins.

A further aspect of the present invention relates to a method for producing a carboxylic acid ester, comprising reacting a carboxylic acid and an alcohol in the presence of the catalyst composition of the present invention to effect an esterification reaction. In addition, a further aspect of the present invention relates to a method for producing a carboxylic acid ester, comprising a step of reacting a carboxylic acid ester and an alcohol in the presence of the catalyst composition of the present invention to effect an ester exchange reaction (hereinafter, these methods are also referred to as the "method for producing a carboxylic acid ester of the present invention").

In the above esterification reaction or transesterification reaction step, the catalyst composition of the present invention can be used in a form that allows contact with the catalyst composition of the present invention, a solution or suspension of a carboxylic acid and a carboxylic acid ester, and an alcohol. For example, the catalyst composition of the invention may be in bed or column form.

The carboxylic acid used in the method for producing a carboxylic acid ester of the present invention is not particularly limited, but includes a straight or branched aliphatic chain having 1 to 30 carbon atoms and preferably 1 to 18 carbon atoms having one or more carboxy groups (for example, C2 to C4 lower, C5 to C12 intermediate, and C13 or higher higher aliphatic chains) or aliphatic carboxylic acids or aromatic carboxylic acids having an aromatic ring. Specifically, for example, saturated fatty acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, stearic acid; Acids; aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecanedioic acid; and aromatic dicarboxylic acids such as fumaric acid, maleic acid, phthalic acid, terephthalic acid and isophthalic acid. These carboxylic acids may optionally have substituents such as alkyl, alkenyl, cycloalkyl, aryl, alkoxy, nitro, cyano, and halogen. In addition, these carboxylic acids may use 1 type, and may use 2 or more types together.

The alcohol used in the method for producing a carboxylic acid ester of the present invention is not particularly limited. For example, a linear or branched monohydric alcohol or polyhydric alcohol having 1 to 22 carbon atoms, preferably 1 to 12 carbon atoms can be used. Examples of alcohols include linear or branched aliphatic monohydric alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, decanol, undecanol, and dodecanol; alicyclic monohydric alcohols such as cyclohexanol, cyclododecanol, and 2-ethyl-1-hexanol; aromatic monohydric alcohols such as benzyl alcohol; polyhydric alcohol; These alcohols may be primary, secondary or tertiary alcohols. These alcohols may optionally have substituents such as alkyl, alkenyl, cycloalkyl, aryl, alkoxy, nitro, cyano, and halogen. In addition, these alcohols may use 1 type, and may use 2 or more types together.

The carboxylic acid ester used in the method for producing a carboxylic acid ester of the present invention is not particularly limited, but for example, an aliphatic carboxylic acid or aromatic carboxylic acid having a linear or branched aliphatic chain or aromatic ring having 1 to 30 carbon atoms, preferably 1 to 18 carbon atoms, and an ester or partial ester of a monohydric alcohol or polyhydric alcohol having a linear or branched chain having 1 to 22 carbon atoms, preferably 1 to 12 carbon atoms, as exemplified above can be used. One of these carboxylic acid esters may be used, or two or more thereof may be used in combination.

Carboxylic acids, alcohols, and carboxylic acid esters used in the above production method may be those synthesized by known synthesis methods or commercially available ones.

The esterification reaction and the transesterification reaction can be performed with reference to conventional esterification reactions and transesterification reactions using resins composed of polymers of para-phenolsulfonic acid and formaldehyde (for example, para-phenolsulfonic acid resins described in Non-Patent Documents 1 to 3, etc.).
From the viewpoint of obtaining a resin in high yield, the reaction ratio (molar ratio) of carboxylic acid or carboxylic acid ester and alcohol is usually in the range of 1:10 to 10:1, preferably 1:1 to 1:3.

The amount of the catalyst composition to be used is not particularly limited and can be appropriately selected depending on the intended purpose. The molar ratio of the carboxylic acid or carboxylic acid ester to the catalyst is usually 1:0.001 to 1:1, preferably 1:0.01 to 1:0.1. The ratio is preferably 1:0.001 or more and 1:1 or less from the viewpoint of sufficient reaction.

The reaction temperature can be appropriately selected in consideration of the composition of the reaction solution, the heat resistance temperature of the catalyst, etc., but is usually 50 to 130°C. The higher the reaction temperature, the faster the reaction rate and the more efficient reaction can be carried out.

The above esterification reaction and transesterification reaction do not particularly require the use of a solvent, but may be used as necessary. Solvents that can be used are suitable for forming a homogeneous phase with the reaction substrate, and for example, hydrocarbons, ethers, esters, alcohols and the like can be used.

After the esterification reaction, if desired, it can be isolated and purified by a known isolation and purification method, for example, general operations such as filtration, concentration, extraction, distillation, sublimation, recrystallization, and column chromatography.

As described above, the catalyst composition of the present invention is a catalyst with high catalytic activity. Here, high catalytic activity is not limited, but is, for example, a yield of 70% or more, 80% or more, or 85% or more. Yield can be determined by a known method, for example, the method described in Examples below.

Also, the catalyst composition can be easily separated from the reaction mixture by known methods such as filtration and washing and reused. The catalyst of the present invention is highly reusable. Here, high reusability is not limited, but for example, the activity of three times reuse is 85% or more, 90% or more, 95% or more, 99% or more, 95% or more of the activity of the first use. Reusability can be determined by a known method, for example, the method described in Examples below.

The present invention also relates to a reactor comprising at least a reaction vessel filled with the catalyst composition of the present invention, one or more inlets for supplying reactants to said reaction vessel, and one or more outlets for removing reaction products from the reaction vessel. In an embodiment in which the reactor of the present invention is used for ester synthesis, carboxylic acid or carboxylic acid ester and alcohol are supplied into the reaction vessel from the same or different supply ports, and the produced carboxylic acid ester is discharged from the outlet and collected. Separately, an outlet for discharging the by-product may be provided. The shape of the reaction vessel is not particularly limited, and examples thereof include a cylindrical column shape. The reaction device may further include a heating device or the like for heating the reaction vessel to a predetermined temperature.

Each of the catalyst composition, production method, and reaction apparatus of the present invention can be used in a batch-type reaction system or in a flow-type reaction system. The latter aspect is preferable from the viewpoint of yield or reaction efficiency.

EXAMPLES The present invention will be specifically described below with reference to Examples. However, the present invention is not limited to the aspects of the following examples.

<SEM/EDS analysis>
SEM (Scanning Electron Microscope) analysis was performed using TM 3030 Plus (Hitachi High-Technologies Corporation), and EDS (Energy Dispersive X-ray Spectrometer) analysis was performed using an analyzer attached to the SEM.

<Elemental analysis>
Elements were confirmed using CHN coder MT-6 (Yanako Analysis Industry Co., Ltd.) and ion chromatography ICS-1500 (Thermo Fisher Scientific Co., Ltd.).

<Observation with an optical microscope>
Optical microscope observation was performed using SM2 1000 (Nikon Corporation).

<FT-IR>
FT-IR (Fourier Transform Infrared Spectroscopy) analysis was performed using FT-IR-6200 (JASCO Corporation).

<p-phenolsulfonic acid resin>
The p-phenolsulfonic acid resins used as catalysts in Comparative Examples were synthesized by the methods described in Non-Patent Documents 1-3.

<Preparation of m-phenolsulfonic acids>
1. Synthesis of sodium m-phenolsulfonate
Sodium m-phenolsulfonate was synthesized based on the literature (Russian Journal of General Chemistry, 2003, 73, 1095-1099). Specifically, it was carried out as follows.

1-1 Reagents The reagents shown in the table below were used.

1-2 Experimental method
1.733 g (10 mmol) of 3-Aminobenzenesulfonic acid and 20 mL of ultrapure water were added to a 100 mL eggplant-shaped flask and stirred using a stirrer and a stirrer (500 rpm). Subsequently, a 40 wt% sodium hydroxide aqueous solution was added to adjust the pH of the reaction solution to 7.5 to 8.5. After that, the reaction solution was cooled to 5 to 10° C., and 1.61 mL (10.15 mmol) of 30 wt % sodium nitrite aqueous solution was added. Next, the temperature of the reaction solution was raised to 15 to 18° C., and a 30 wt % sulfuric acid aqueous solution was added until the reaction solution reached pH<3. After stirring for 30 minutes at room temperature, 48.5 mg (0.5 mmol) of amidosulfuric acid was added, and the mixture was heated to 65° C. using an oil bath and reacted for 18 hours. After the reaction, the solution was allowed to cool at room temperature for 30 minutes. Subsequently, the reaction solution was neutralized with barium carbonate until the pH reached 7. Then, suction filtration was performed using a Kiriyama funnel and filter paper (No. 4) having retained particles of 1 micron, and the filtrate was collected in a 200 mL eggplant-shaped flask. The solution was dried in a lyophilizer to give an orange solid.

1-3 Post-processing
150 mL of ethanol was added to the solid obtained in a 200 mL eggplant-shaped flask, and the desired product was dissolved using an ultrasonicator for 60 minutes. After that, a filtrate was obtained by suction filtration. After the solvent was removed from the filtrate using a rotary evaporator, the residue was vacuum-dried overnight to obtain an orange desired product. The yield was 66.9% (theoretical yield: 1.96 g, experimental yield: 1.31 g). The structure of the resulting product was analyzed by FT-IR and NMR. As a result, the structure of sodium m-phenolsulfonate was confirmed.

2. Preparation of m-phenolsulfonic acid The metal salt of m-phenolsulfonic acid obtained above was subjected to cation exchange to prepare m-phenolsulfonic acid. Specifically, m-phenolsulfonic acid was prepared by the following method.

16.4 g of Amberlyst@16wet (ion exchange resin beads) was placed in a 100 mL beaker, added with 50 mL of ultrapure water, and left at room temperature for about 20 hours. After washing once with ultrapure water, the tube was transferred to a chromatographic tube, washed with 10 mL of ultrapure water, and filled with ultrapure water until the top of the resin beads was immersed. On the other hand, 400 mg (2.03 mmol) of sodium m-phenolsulfonate was dissolved in 0.5 mL ultrapure water using an ultrasonicator. The dissolved sodium m-phenolsulfonate was slowly added dropwise to the resin tower. Subsequently, while adding ultrapure water, the cock of the chromatography tube was opened, and the solution was received in the test tube until the pH of the solution became neutral. About 30 mL of the resulting solution was transferred to a 50 mL eggplant flask and freeze-dried for 15 hours to give a dark orange viscous liquid as the product. The yield was 97.06% (theoretical yield: 353.6 mg, experimental yield: 343.2 mg).

<Example 1>
An m-phenolsulfonic acid resin was obtained using m-phenolsulfonic acid as phenolsulfonic acids and formaldehyde solution as formaldehydes. Since the monomer m-phenolsulfonic acid itself was allowed to act as an acid catalyst, no additional catalyst was added.

100 mg (0.578 mmol) of the m-phenolsulfonic acid obtained above was added to the test tube, followed by 0.28 mL of ultrapure water and 95.9 mg (1.1 mmol) of the formaldehyde solution described in Table 2 above, respectively, and the upper part of the test tube was filled with cotton. This solution was reacted for 72 hours under conditions of 120° C. and 1000 rpm using chemistation (manufactured by EYELA). A black solid was obtained as a product after the reaction.

4 mL of methanol was added to the solid in the test tube obtained above, and suction filtration was then performed using a Kiriyama funnel and a filter paper (No, 4) having retained particles of 1 micron. At that time, the product was washed with ultrapure water, methanol and acetone. Finally, the product was vacuum-dried for 24 hours and pulverized in a mortar to obtain the desired product (resin of Example 1). Yield was 100.1 mg. The obtained resin of Example 1 was analyzed. The results of SEM/EDS analysis of the resin of Example 1 are shown in FIG. 1, the results of optical microscope observation in FIG. 6, the results of elemental analysis in FIG. 7, and the results of FT-IR analysis in FIG.

<Example 2>
Using m-phenolsulfonic acid metal salts as phenolsulfonic acids and sulfuric acid shown in Table 3 below as an acid catalyst, formaldehydes were polymerized with paraformaldehyde to obtain m-phenolsulfonic acid resins. Specifically, it was carried out as follows.

98.25 mg (0.5 mmol) of sodium m-phenolsulfonate synthesized above and 30.0 mg of paraformaldehyde described in Table 3 above were added to a capped test tube. Subsequently, 0.25 mL of a 2 M sulfuric acid aqueous solution was added, and the reaction was carried out for 24 hours under the conditions of 120° C. and 500 rpm using a chemistration and a stirrer. After 24 hours, a black target was obtained.

After the above reaction, 4 mL of methanol was added to the solid in the test tube, and suction filtration was then performed using a Kiriyama funnel and filter paper (No. 4) having retained particles of 1 micron. At that time, the product was washed with ultrapure water, 5 wt% hydrochloric acid aqueous solution (listed in Table 3 above), methanol and acetone. Finally, the product was vacuum-dried for 24 hours and pulverized in a mortar to obtain the desired product (resin of Example 2). Yield was 96.5 mg. The obtained resin of Example 2 was analyzed. The results of SEM/EDS analysis of the resin of Example 2 are shown in FIG. 2, the results of optical microscope observation in FIG. 6, the results of elemental analysis in FIG. 7, and the results of FT-IR analysis in FIG.

<Example 3>
A m-phenolsulfonic acid metal salt was polymerized with paraformaldehyde as a formaldehyde using sodium hydroxide as a basic catalyst using phenolsulfonic acids as a basic catalyst to obtain an m-phenolsulfonic acid resin. Specifically, it was carried out as follows.

225.9 mg (1.15 mmol) of sodium m-phenolsulfonate synthesized above and 76.6 mg of paraformaldehyde described in Table 4 above were added to a capped test tube. Next, 0.112 mL of ultrapure water was added and completely dissolved. After that, 20.3 mg of an aqueous sodium hydroxide solution adjusted to 40 wt % shown in Table 4 above was added and the test tube was capped. This solution was reacted for 1 hour with stirring at 65° C. and 800 rpm using Chemistation. After the reaction, 11 μL of 40 wt % sodium hydroxide aqueous solution shown in Table 4 above and 7 μL of ammonia water shown in Table 4 above were added, and the mixture was reacted for 20 hours with stirring at 100° C. and 800 rpm using Chemistry. After the reaction, the product was washed with ultrapure water and isopropanol. Finally, the product was vacuum-dried for 24 hours and pulverized in a mortar to obtain the desired product.

The solid obtained above was filled in a cylindrical filtering device, and a 7.5 wt % hydrochloric acid aqueous solution shown in Table 4 was poured over the solid to perform ion exchange. After that, the catalyst was washed with ultrapure water until the pH of the washed solution became 7.

The solid obtained above was washed with isopropanol, vacuum-dried for 24 hours, and pulverized in a mortar to obtain the desired product (resin of Example 3). Yield was 248.3 mg. The resin of Example 3 was analyzed. The results of SEM/EDS analysis of the resin of Example 3 are shown in FIG. 3, the results of optical microscope observation in FIG. 6, the results of elemental analysis in FIG. 7, and the results of FT-IR analysis in FIG.

<Example 4>
A mixture of m-phenolsulfonic acid sodium salt and p-phenolsulfonic acid was polymerized as phenolsulfonic acids, using sodium hydroxide and aqueous ammonia as basic catalysts, and paraformaldehyde as formaldehydes to obtain m-phenolsulfonic acid-p-phenolsulfonic acid resin. Specifically, it was carried out as follows.

To a capped test tube was added 180.8 mg (0.92 mmol) of sodium m-phenolsulfonate synthesized above, 47.1 mg (0.23 mmol) of p-phenolsulfonic acid listed in Table 5 above, and 76.6 mg of paraformaldehyde listed in Table 5 above. Next, 0.112 mL of ultrapure water was added and completely dissolved. After that, 20.3 mg of an aqueous sodium hydroxide solution adjusted to 40 wt % shown in Table 5 above was added and the test tube was capped. This solution was reacted for 1 hour with stirring at 65° C. and 800 rpm using Chemistation. After the reaction, 11 μL of 40 wt % sodium hydroxide aqueous solution shown in Table 5 above and 7 μL of ammonia water shown in Table 5 above were added, and the mixture was reacted for 20 hours with stirring at 100° C. and 800 rpm using Chemistry. After the reaction, the product was washed with ultrapure water and isopropanol.
After ion exchange and washing with isopropanol in the same manner as the resin of Example 3, the product was finally vacuum-dried for 24 hours and ground in a mortar to obtain the desired product (resin of Example 4). Yield was 251.0 mg. The obtained resin of Example 4 was analyzed. The results of SEM/EDS analysis of the resin of Example 4 are shown in FIG. 4, the results of optical microscope observation are shown in FIG. 6, the results of elemental analysis are shown in FIG. 7, and the results of FT-IR analysis are shown in FIG.

<Example 5>
A mixture of sodium m-phenolsulfonic acid synthesized above and phenol was polymerized with paraformaldehyde as formaldehyde using sodium hydroxide and aqueous ammonia as basic catalysts as phenolsulfonic acids to obtain m-phenolsulfonic acid-phenol resin. Specifically, it was carried out as follows.

To a capped test tube was added 180.8 mg (0.92 mmol) of sodium m-phenolsulfonate synthesized above, 21.6 mg (0.23 mmol) of phenol, and 76.6 mg of paraformaldehyde described in Table 5 above. Next, 0.112 mL of ultrapure water was added and completely dissolved. After that, 20.3 mg of an aqueous sodium hydroxide solution adjusted to 40 wt % shown in Table 5 above was added and the test tube was capped. This solution was reacted for 1 hour with stirring at 65° C. and 800 rpm using Chemistation. After the reaction, 11 μL of 40 wt % sodium hydroxide aqueous solution shown in Table 5 above and 7 μL of ammonia water shown in Table 5 above were added, and the mixture was reacted for 20 hours with stirring at 100° C. and 800 rpm using Chemistry. After the reaction, the product was washed with ultrapure water and isopropanol.
After ion exchange and washing with isopropanol in the same manner as the resin of Example 3, the product was finally vacuum dried for 24 hours and ground in a mortar to obtain the target product (resin of Example 5). Yield was 224.8 mg. The obtained resin of Example 5 was analyzed. The results of SEM/EDS analysis of the resin of Example 5 are shown in FIG. 5, the results of optical microscope observation in FIG. 6, the results of elemental analysis in FIG. 7, and the results of FT-IR analysis in FIG.

<Example 6>
6. Synthesis of methyl acrylate using a solid acid catalyst Methyl acrylate was synthesized using a solid acid catalyst (m-phenolsulfonic acid resin (resins of Examples 1 to 3), meta-para-phenolsulfonic acid resin (resin of Example 4), and m-phenolsulfonic acid-phenol resin (resin of Example 5). Specifically, it was carried out as follows.

6-1 Reagents The reagents shown in the table below were used.

6-2 Experimental Method A solid acid catalyst was added to a test tube with a cap, followed by 216.2 mg (3.0 mmol) of acrylic acid and 192.2 mg (6.0 mmol) of dehydrated methanol, and a cap and sealing tape were attached. This solution was subjected to reaction using chemistation under conditions of 90° C. and 300 rpm for 15 hours (only 6-4-6 was experimented using an oil bath). The amount of the catalyst introduced was such that the sulfur atom, which is the active site of the catalyst, was 0.5 mol % with respect to acrylic acid.

6-3 Determination method for acrylic acid
After the reaction of 6-2, the test tube was allowed to cool at room temperature for 30 minutes. After that, the internal standard substance diethylene glycol diethyl ether was added, and the mixture was diluted with 4 mL of diethyl ether and stirred well. 0.1 mL of this solution was taken and diluted with 0.4 mL of diethyl ether. Subsequently, 1 μL of the solution was taken out with a syringe and measured using GC-FID (6850 series manufactured by Agilent). DB-624UI (manufactured by Agilent) was used as a measurement column.

6-4 Experimental results
6-4-1 Experimental results with m-phenolsulfonic acid resin (resin of Example 1) using acid catalyst The yield of methyl acrylate was calculated as follows.
Methyl acrylate yield (%) = (number of moles of methyl acrylate produced) / (number of moles of supplied acrylic acid) x 100
Methyl acrylate GC yield: 87.9%
Acrylic acid recovery rate: 14.4%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 85.9 : 14.1

Experimental results with m-phenolsulfonic acid resin (resin of Example 2) with 6-4-2 acid catalyst Methyl acrylate GC yield: 84.1%
Acrylic acid recovery rate: 14.2%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 85.6 : 14.4

6-4-3 Synthesis of m-phenolsulfonic acid resin using basic catalyst (resin of Example 3)
Methyl acrylate GC yield: 89.2%
Acrylic acid recovery rate: 14.9%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 85.7 : 14.3

Experimental results with 6-4-4 m-para copolymer (resin of Example 4) Methyl acrylate GC yield: 89.1%
Acrylic acid recovery rate: 14.9%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 85.7 : 14.3

Experimental results with 6-4-5 m-phenol copolymer (resin of Example 5) Methyl acrylate GC yield: 87.6%
Acrylic acid recovery rate: 17.4%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 83.4 : 16.6

6-4-6 Experimental results with p-phenolsulfonic acid resin (comparative example)
Methyl acrylate GC yield: 77.1%
Acrylic acid recovery rate: 16.2%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 82.6 : 17.4

The catalyst of the present invention showed higher activity than the conventional (comparative) catalyst (p-phenolsulfonic acid resin).

<Example 7>
7. Reuse Experiment Using the catalysts of Examples 1 to 3 and Comparative Example, the experiment conducted in 6-2 was repeated.

7-1 Experimental method
After the experiment of 6-2, 4 mL of methanol was added to the test tube and collected with a membrane filter (manufactured by Merck) with a hole diameter of 0.2 μm. The recovered solid acid catalyst was washed with methanol and acetone, vacuum-dried for 24 hours, and used in the next experiment.
7-2. Experimental Results The results are shown in Figures 13-16.
As shown in FIGS. 13 to 15, the catalysts of the examples of the present invention maintained high activity even after being reused 10 times. In contrast, as shown in FIG. 16, the activity of the comparative example catalyst (p-phenolsulfonic acid resin) significantly decreased after being reused three times.

<Example 8>
A mixture of a metal salt of m-phenolsulfonic acid and phenol was used as phenolsulfonic acids, and sulfuric acid shown in Table 7 below was used as an acid catalyst, and formaldehydes were polymerized with paraformaldehyde to obtain an m-phenolsulfonic acid-phenol resin. Specifically, it was carried out as follows.

To a capped test tube was added 88.3 mg (0.45 mmol) of sodium m-phenolsulfonate synthesized above, 4.7 mg (0.05 mmol) of phenol, and 50.6 mg of paraformaldehyde described in Table 7 above. Next, 0.25 mL of 4 M sulfuric acid aqueous solution was added and the test tube was capped. This solution was reacted for 7 days with stirring at 120° C. and 300 rpm using Chemistation.

4 mL of methanol was added to the solid in the test tube obtained by the above reaction, and suction filtration was performed using a membrane filter with retained particles of 0.2 μm. At that time, the product was washed with ultrapure water, 7.5 wt% hydrochloric acid aqueous solution, methanol and isopropanol. Finally, the product was vacuum-dried for 24 hours and pulverized in a mortar to obtain the desired product (resin of Example 8). Yield was 88.9 mg. As in Example 1, it was confirmed by FT-IR and elemental analysis that m-phenolsulfonic acid-phenol resin was obtained. Further, when the surface was analyzed in the same manner as above, the surface property was such that sulfur atoms were uniformly dispersed on the resin surface as in the case of the resin of Example 1 and the like.

<Example 9>
A mixture of m-phenolsulfonic acid metal salt and p-cresol was polymerized as phenolsulfonic acids with paraformaldehyde as formaldehyde using sulfuric acid shown in Table 8 below as an acid catalyst to obtain m-phenolsulfonic acid-p-cresol resin. Specifically, it was carried out as follows.

98.3 mg (0.5 mmol) of sodium m-phenolsulfonate synthesized above, 54.0 mg (0.5 mmol) of p-cresol, and 69.0 mg of paraformaldehyde were added to a capped test tube. Next, 0.5 mL of 2 M sulfuric acid aqueous solution was added and the test tube was capped. This solution was reacted for 24 hours with stirring at 120° C. and 300 rpm using Chemistation.

8 mL of the solid in the test tube obtained above was added to methanol, and suction filtration was performed using a membrane filter with retained particles of 0.2 μm. At that time, the product was washed with ultrapure water, 7.5 wt% hydrochloric acid aqueous solution, methanol and isopropanol. Finally, the product was vacuum-dried for 24 hours and pulverized in a mortar to obtain the desired product (resin of Example 9). Yield was 121.6 mg. As in Example 1, it was confirmed by FT-IR and elemental analysis that an m-phenolsulfonic acid-p-cresol resin was obtained. Further, when the surface was analyzed in the same manner as above, the surface property was such that sulfur atoms were uniformly dispersed on the resin surface as in the case of the resin of Example 1 and the like.

<Example 10>
Using a mixture of m-phenolsulfonic acid metal salt and 4-dodecylphenol as phenolsulfonic acids, sulfuric acid shown in Table 9 below was used as an acid catalyst, and formaldehydes were polymerized with paraformaldehyde to obtain m-phenolsulfonic acid-4-dodecylphenol resin. Specifically, it was carried out as follows.

98.3 mg (0.5 mmol) of sodium m-phenolsulfonate synthesized above, 131.2 mg (0.5 mmol) of 4-dodecylphenol, and 68.9 mg of paraformaldehyde were added to a capped test tube. Next, 0.5 mL of 2 M sulfuric acid aqueous solution was added and the test tube was capped. This solution was reacted for 24 hours with stirring at 120° C. and 300 rpm using Chemistation.

8 mL of methanol was added to the solid in the test tube obtained above, and suction filtration was performed using a membrane filter with retained particles of 0.2 μm. At that time, the product was washed with ultrapure water, 7.5 wt% hydrochloric acid aqueous solution, methanol and isopropanol. Finally, the product was vacuum dried for 24 hours and pulverized in a mortar to obtain the desired product (resin of Example 10). Yield was 124.5 mg. As in Example 1, it was confirmed by FT-IR and elemental analysis that m-phenolsulfonic acid-4-dodecylphenol resin was obtained. Further, when the surface was analyzed in the same manner as above, the surface property was such that sulfur atoms were uniformly dispersed on the resin surface as in the case of the resin of Example 1 and the like.

<Example 11>
11. Synthesis of methyl acrylate using a solid acid catalyst Solid acid catalysts (m-phenolsulfonic acid-phenol resin (resin of Example 8), m-phenolsulfonic acid-p-cresol resin (resin of Example 9), and m-phenolsulfonic acid-4-dodecylphenol resin (resin of Example 10) were used to synthesize methyl acrylate. Specifically, it was carried out as follows.

11-1 Reagents The reagents shown in the table below were used.

11-2 Experimental method Each solid acid catalyst was added to a capped test tube, followed by 216.2 mg (3.0 mmol) of acrylic acid and 192.2 mg (6.0 mmol) of dehydrated methanol, and the cap and seal tape were attached. This solution was reacted for 15 hours under conditions of 90° C. and 300 rpm using chemistation. The amount of the catalyst introduced was such that the sulfur atom, which is the active site of the catalyst, was 0.5 mol % with respect to acrylic acid.

11-3 Determination method for acrylic acid and methyl acrylate
After the reaction of 11-2, the test tube was allowed to cool at room temperature for 30 minutes. After that, the internal standard substance diethylene glycol diethyl ether was added, and the mixture was diluted with 4 mL of diethyl ether and stirred well. 0.1 mL of this solution was taken and diluted with 0.4 mL of diethyl ether. Subsequently, 1 μL of the solution was taken out with a syringe and measured using GC-FID (6850 series manufactured by Agilent). DB-624UI (manufactured by Agilent) was used as a measurement column.

11-4 Experimental results
11-4-1 Results of experiment with copolymer of sodium m-phenolsulfonate and phenol using acid catalyst (resin of Example 8) The yield of methyl acrylate was calculated in the same manner as in Example 6.
Methyl acrylate GC yield: 77.4%
Acrylic acid recovery rate: 13.4%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 85.2 : 14.8

Experimental results with copolymer of sodium m-phenolsulfonate and p-cresol (resin of Example 9) using 11-4-2 acid catalyst Methyl acrylate GC yield: 81.4%
Acrylic acid recovery rate: 12.3%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 86.8 : 13.2

Experimental results with copolymer of sodium m-phenolsulfonate and 4-dodecylphenol (resin of Example 10) using 11-4-3 acid catalyst Methyl acrylate GC yield: 82.6%
Acrylic acid recovery rate: 13.6%
(Methyl acrylate GC yield) : (Acrylic acid recovery rate) = 85.8 : 14.2

The catalyst of the invention showed high activity.

<Example 12>
12. Continuous Flow Synthesis of Methyl Acrylate Using m-Phenolsulfonic Acid Polymer Produced Using Acid Catalyst Methyl acrylate was synthesized in a continuous flow using the m-phenolsulfonic acid resin synthesized in Example 2 as a solid acid catalyst. Specifically, it was carried out as follows.
The apparatus shown in FIG. 17 and below was used.

12-1 Experimental equipment Syringe pump (manufactured by YMC)
PTFE tube (1/16'' x 1.00mm)
Column for catalyst packing (Omnifit column length 10 cm, inner diameter 6.6 mm)
Heater and temperature control unit (manufactured by YMC)
Back pressure valve (manufactured by DFC)

12-2 Reagents The reagents shown in the table below were used.

12-3 Packing and Conditioning of Solid Acid 327 mg and 653 mg of the solid acid catalyst prepared by the method of Example 2 were packed in a catalyst packing column (omnifit column) so that elemental sulfur was 1.1 mmol or 2.2 mmol, respectively. After that, the inside of the column was heated to 90° C. using a syringe pump and a heater, and 10 mL of methanol was flowed through the column at a flow rate of 100 μL/min.

12-4 Experimental method A solution was prepared so that the molar ratio of acrylic acid and methanol was 1:2. This solution was then filled into a syringe. Next, the apparatus and the column were connected as shown in the diagram of FIG. 17, and the internal temperature of the column was adjusted to 90.degree. As a pretreatment, the experiment was started after flowing 5 mL of the reaction solution at 100 μL/min.
After passing through the column, the solution passed through a back pressure valve and was collected from the outlet of the tube into a vial chilled in an ice bath.

12-5 Determination method for acrylic acid and methyl acrylate
After measuring the weight of the reaction solution of 12-3, the internal standard substance diethylene glycol diethyl ether was added. 2 μL of the solution was diluted with 500 μL of diethyl ether and then stirred well. Next, 1 μL of this solution was taken out and measured using GC-FID (6850 series manufactured by Agilent). DB-624UI (manufactured by Agilent) was used as a measurement column.

12-6 Experimental Results Using the solid acid catalyst of the present invention, methyl acrylate was efficiently synthesized by continuous flow synthesis. The results for a catalyst loading of 327 mg are shown in the table below.

<Example 13>
13. Esterification reaction of various acrylic compounds and alcohols using a continuous-flow apparatus Esters of various acrylic compounds and alcohols were continuously synthesized using the m-phenolsulfonic acid resin synthesized in Example 2 as a solid acid catalyst. Specifically, it was carried out as follows.

13-1 Reagents The reagents shown in the table below were used.

13-2 Experimental Apparatus The same experimental apparatus as in 12-1 was used. Also, the column packed with the catalyst was the same as in 12-1 and was conditioned by the method in 12-3.

13-3 Experimental method A solution was prepared so that the molar ratio of carboxylic acid (acrylic acid compound) and alcohol was 1:2. This solution was then filled into a syringe. Next, the apparatus and the column were connected as shown in the diagram of FIG. 17, and the internal temperature of the column was adjusted to 90.degree. As a pretreatment, the experiment was started after flowing 5 mL of the reaction solution at 100 μL/min.
After passing through the column, the solution passed through a back pressure valve and was collected from the outlet of the tube into a vial chilled in an ice bath.

13-4 Quantitative methods for raw materials and target products
After measuring the weight of the reaction solution of 13-3, the internal standard substance diethylene glycol diethyl ether was added. 2 μL of the solution was diluted with 500 μL of diethyl ether and then stirred well. Next, 1 μL of this solution was taken out and measured using GC-FID (6850 series manufactured by Agilent). DB-624UI (manufactured by Agilent) was used as a measurement column.

13-5 Experimental results
13-5-1 Esterification reaction of acrylic acid and ethanol Catalyst loading: 327 mg
Reaction solution delivery speed: 25 μL/min
Ethyl acrylate GC yield: 94.6%
Acrylic acid recovery rate: 1.0%

13-5-2 Esterification reaction of acrylic acid and n-butanol Catalyst loading: 327 mg
Reaction solution feeding rate: 10 μL/min
Butyl acrylate GC yield: 76.6%
Acrylic acid recovery rate: 16.8%

13-5-3 Esterification reaction of acrylic acid and 2-ethyl-1-hexanol Catalyst loading: 653 mg
Reaction solution feeding speed: 20 μL/min
2-Ethylhexyl acrylate GC yield: 74.4%
Acrylic acid recovery rate: 10.2%

13-5-4 Esterification reaction of acrylic acid and n-octanol Catalyst loading: 653 mg
Reaction solution delivery rate: 50 μL/min
Octyl acrylate GC yield: 53.2%
Acrylic acid recovery rate: 26.2%

13-5-5 Esterification reaction of methacrylic acid and methanol Catalyst loading: 327 mg
Reaction solution delivery speed: 25 μL/min
Methyl methacrylate GC yield: 95.4%
Methacrylic acid recovery rate: 2.4%

13-5-6 Esterification reaction of crotonic acid and methanol Catalyst loading: 653 mg
Reaction solution feeding speed: 20 μL/min
Methyl crotonate GC yield: 87.2%
Crotonic acid recovery: 0.8%

13-5-7 Esterification reaction of tiglic acid and methanol Catalyst loading: 653 mg
Reaction solution feeding speed: 20 μL/min
Methyl tiglate GC yield: 87.7%
Tiglic acid recovery rate: 12.3%

Using the solid acid catalyst of the present invention, esters of various acrylic compounds and alcohols were efficiently synthesized.

<Example 14>
14. Esterification reaction of acetic acid and n-octanol using a continuous-flow apparatus Using the m-phenolsulfonic acid resin synthesized in Example 2 as a solid acid catalyst, an ester of acetic acid and n-octanol was synthesized in a continuous flow. Specifically, it was carried out as follows.

14-1 Reagents The reagents shown in the table below were used.

14-2 Experimental Apparatus The same experimental apparatus as in 12-1 was used. Also, the column packed with the catalyst was the same as in 12-1 and was conditioned by the method in 12-3.

14-3 Experimental method A solution was prepared so that the molar ratio of acetic acid and n-octanol was 2:1. This solution was then filled into a syringe. Next, the apparatus and the column were connected as shown in the diagram of FIG. 17, and the internal temperature of the column was adjusted to 90.degree. As a pretreatment, the experiment was started after flowing 5 mL of the reaction solution at 100 μL/min.
After passing through the column, the solution passed through a back pressure valve and was collected from the outlet of the tube into a vial chilled in an ice bath.

14-4 Quantitative methods for raw materials and target products
After measuring the weight of the reaction solution of 14-3, the internal standard substance diethylene glycol diethyl ether was added. After diluting 2 μL of the solution with 500 μL of diethyl ether, the mixture was well stirred. Next, 1 μL of this solution was taken out and measured using GC-FID (6850 series manufactured by Agilent). DB-624UI (manufactured by Agilent) was used as a measurement column.

14-5 Experimental Results The results are shown in the table below.

Esters of saturated aliphatic carboxylic acids and alcohols were synthesized using the solid acid catalysts of the present invention.

<Example 15>
15. Esterification reaction of oleic acid and methanol using a continuous flow device (biodiesel fuel synthesis)
An m-phenolsulfonic acid resin was synthesized in the same manner as in Example 2. However, the specific conditions are as follows.

Using the obtained m-phenolsulfonic acid resin as a solid acid catalyst, an ester of oleic acid and methanol was synthesized in a continuous flow. Specifically, it was carried out as follows.

15-1 Reagents The reagents shown in the table below were used.

15-2 Experimental Apparatus The same experimental apparatus as in 12-1 was used. Also, the column packed with the catalyst was the same as in 12-1 and was conditioned by the method in 12-3.

15-3 Experimental method A solution was prepared so that the molar ratio of oleic acid and methanol was 1:5. This solution was then filled into a syringe. Next, the apparatus and the column were connected as shown in the diagram of FIG. 17, and the internal temperature of the column was adjusted to 90.degree. As a pretreatment, the experiment was started after flowing 5 mL of the reaction solution at 100 μL/min.
After passing through the column, the solution passed through a back pressure valve and was collected from the outlet of the tube into a vial chilled in an ice bath.

15-4 Quantification Method of Target Product After sampling the solution flowing from the flow device for a specified time, methanol and water were removed with ether and water. The desired product was then isolated with a silica column and the yield was determined.

15-5 Experimental results Catalyst loading: 653 mg
Reaction solution delivery rate: 50 μL/min
Isolated yield of methyl oleate: 92%

An ester of oleic acid and methanol useful as a biodiesel fuel was synthesized using the solid acid catalyst of the present invention.

The catalyst composition and meta-phenolsulfonic acid resin of the present invention can be used variously as an acid catalyst, and can be suitably used as an esterification reaction catalyst and a transesterification reaction catalyst, for example.

Claims (7)

A catalyst composition comprising a novolak-type meta-phenolsulfonic acid resin containing a structural unit represented by general formula (I).
(where m1 is 0.) Further, a catalyst composition comprising the meta-phenolsulfonic acid-based resin according to claim 1, which comprises a structural unit represented by formula (II).

(Where m2 is 0.) Further, a catalyst composition comprising the meta-phenolsulfonic acid-based resin according to claim 1 or 2, which comprises a structural unit represented by formula (III).

(In the formula, R ³ is a substituent inert to the polymerization reaction selected from the group consisting of halogen, hydrocarbon having 1 to 30 carbon atoms, acyl having 1 to 30 carbon atoms, and cyano, and m3 is an integer of 0 to 3.) 4. The catalyst composition according to any one of claims 1 to 3 , which is used for an esterification reaction or a transesterification reaction. A step of reacting a carboxylic acid and an alcohol in the presence of the catalyst composition according to claim 4 to effect an esterification reaction;
A method for producing a carboxylic acid ester, comprising: A step of reacting a carboxylic acid ester and an alcohol in the presence of the catalyst composition of claim 4 to effect a transesterification reaction;
A method for producing a carboxylic acid ester, comprising: A reactor comprising a reaction vessel filled with the catalyst composition according to any one of claims 1 to 4 , one or more supply ports for supplying reaction raw materials to the reaction vessel, and one or more outlets for taking out the reaction product from the reaction vessel.