JPS6136815B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing γ-alkyl-γ-butyrolactones, followed by dehydration condensation to produce 2-cyclopentenones. 2-Cyclopentenones are not only useful as starting materials for fragrances, medicines, agricultural chemicals, etc.
Many are fragrance substances themselves. for example,
These include synthetic intermediates for diasmine-based fragrance ingredients such as diasmone (dihydrodiasmone) and methyl diasmonate (methyl dihydrodiasmonate). The following are the main conventionally known methods for producing 2-cyclopentenones. (1) A method of heating γ-lactone with phosphorus pentoxide. [J.Am.Chem.Soc., 66 , 4 (1944) and J.
Am.Chem.Soc., 70 , 1379 (1948)] (2) A method of heating γ-lactone with polyphosphoric acid. [Experientia, 11 (3), 114 (1955)] (3) A method of treating γ-lactone in a mixture of phosphorus pentoxide and methanesulfonic acid at low temperature. [J.Org.
Chem., 38 , (23), 4071 (1973)] (4) A method in which γ-lactone is dehydrated and condensed in the gas phase in the presence of a solid acid catalyst. [Japanese Patent Publication No. 53-18493] The method (1) has a problem in that the yield is low, and this is particularly noticeable in the case of γ-monoalkyl-γ-butyrolactone. Method (2) is reported to have a good yield for γ-methyl-γ-alkyl-γ-butyrolactone, but there is no description regarding γ-monoalkyl-γ-butyrolactone. However, as shown in the comparative example of the present application, γ-monoalkyl-γ-
Butyrolactone has a problem of extremely poor yield. Furthermore, in industrial implementation, it is necessary to recover and reuse polyphosphoric acid, but there is also the problem that it is quite difficult to dehydrate and regenerate it.
Method (3) has almost the same problem as method (2) above regarding reaction yield, and also has the problem that a considerably large amount of phosphorus pentoxide is consumed. Method (4) has almost the same problems with the reaction yield as method (2) above, and there are also other problems such as catalyst regeneration and the fact that the reaction is carried out at high temperatures, making the equipment complicated. . The present inventors have conducted extensive research in order to provide an industrially advantageous manufacturing method that can solve the various problems mentioned above all at once. As a result, surprisingly, they added the idea of using a strong protonation catalyst, which was considered disadvantageous in the conventional thinking, and carrying out the reaction in an inert solvent, and removing the water produced by the reaction from the system. Therefore, in the case of γ-alkyl-γ-butyrolactone having a substituent at the γ-position, not only γ-dialkyl-γ-butyrolactone but also γ-monoalkyl, which has a poor yield with the conventional method, can be used. Even in the case of -γ-butyrolactone, it has become possible to obtain 2-cyclopentenone in an extremely good yield. In addition, methods for producing γ-alkyl-γ-butyrolactone have so far been developed by reducing γ-keto acids, hydrolyzing γ-halo acids, and condensing aliphatic aldehydes and malonic acid in the presence of an alkali catalyst. A method of ring-closing the β,γ-unsaturated carboxylic acid with dilute sulfuric acid or the like, and a method of heating an acrylic acid ester and an alcohol in the presence of di-tert-butyl peroxide are known.
However, these methods have problems such as raw materials not being easily available, being expensive, and having safety issues. On the other hand, the method of electroreductive cross-dimerization of an acrylic ester and a carbonyl compound according to the present invention is an extremely advantageous production method that solves the above problems. Therefore, γ-alkyl-γ
- By selecting the electrolytic reduction cross-dimerization method of the present invention as a method for producing butyrolactone, it has become possible to produce 2-cyclopentenone more advantageously. That is, the present invention provides acrylic ester and general formula R ¹ CH ₂ COR ²
A mixture of carbonyl compounds represented by (R ¹ and R ² are hydrogen or alkyl groups) is electrolytically reduced on a cathode made of lead or an alloy containing lead as a main component, and the general formula

Producing γ-lactones represented by [Formula] (R ¹ and R ² are hydrogen or alkyl groups),
This is a method for producing 2-cyclopentenones in which the γ-lactones are heated in an inert solvent that does not dissolve in water in the presence of a sulfonic acid catalyst while removing water produced by the reaction from the system. . The dehydration condensation reaction of γ-lactone according to the present invention is generally considered to be as follows. That is, the reaction mechanism is proposed to proceed through dehydration under an acid catalyst, as shown in the following formula. [MFANSELL
and SSBrown, J.Chem.Soc., 1958 , 2755~
2761, MFANSELL and MHPALMER,
Quarterly Rev., 18 , 211 (1964)] In these proposals, sulfuric acid, It has been explained that when a strong protonation reagent such as p-toluenesulfonic acid is used, the ethylene bond is preferentially protonated, producing mainly lactones, and it is difficult to proceed in the direction of producing ketones. It is explained that when reagents such as phosphorus pentoxide and trifluoroacetic anhydride are used, protonation to carbonyl groups occurs preferentially in the direction of producing acyllium ions, and ketones are mainly produced. It seems possible to consider the conventionally known manufacturing methods as follows. That is, all of the catalysts used are considered to belong to the latter category of the above catalyst group. Regarding the mechanism of action of dehydration, in the case of methods using phosphorus pentoxide and polyphosphoric acid, the reaction proceeds as the generated water is taken into the catalyst, and the reaction proceeds at high temperatures in the gas phase in the presence of a solid acid catalyst. In the case of the reaction method, it is thought that the produced water is immediately removed due to the high temperature and the reaction proceeds. In contrast to these methods, the method of the present invention can be considered as follows. In other words, the first feature is that the catalyst used is a sulfonic acid catalyst, which is a strong protonation catalyst contrary to the conventional concept, and furthermore, this sulfonic acid catalyst is used in an inert solvent, and the reaction The second feature is that the reaction proceeds while the water thus produced is distilled off from the reaction system together with an inert solvent or alone. Only by combining these two features can the object of the present invention be achieved. For example, as shown in Comparative Example 1, in the conventional reaction using polyphosphoric acid as a catalyst and xylene as a solvent, the yield was extremely poor, and the object of the present invention was not achieved. The reason for kneading can be considered as follows. In other words, it seems that polyphosphoric acid dissolves both the raw material γ-lactone and the product 2-cyclopentenone extremely well, but neither the raw material nor the product is hardly dissolved in the xylene solvent, and is dispersed in the xylene. Since the reaction is proceeding with most of them dissolved in the polyphosphoric acid, it is presumed that the situation is similar to that when polyphosphoric acid was used alone. Further, Comparative Example 2 shows a case where dichloroacetic acid, which is considered to fall under the category of a strong protonating reagent according to the conventional concept, was used as a catalyst. In this case, although the reason is not well understood, the reaction did not proceed at all and the object of the present invention was not achieved. The electrolytic reduction cross-dimerization reaction between an acrylic ester and a carbonyl compound of the present invention can be roughly considered as follows. The reaction proceeds on a cathode made of lead or an alloy containing lead as a main component according to the following reaction formula. Furthermore, the electrolytic conditions for obtaining γ-lactone with good selectivity are significantly different depending on whether the carbonyl compound is a ketone or an aldehyde. The characteristics of each electrolysis condition are described below. The characteristics when the carbonyl compound is a ketone are as follows. That is, the catholyte is made into a homogeneous solution state,
Electrolysis is carried out under acidic conditions using sulfuric acid as a supporting electrolyte, keeping the concentration of methyl acrylate in the catholyte low, and at a low current density. The characteristics when the carbonyl compound is an aldehyde are as follows. That is, by bringing the catholyte into a neutral emulsion state and electrolyzing it in the presence of at least one conductive substance having phase transfer catalytic ability selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts. be. That is, the electrolysis efficiency and products obtained when electrolysis is carried out in an aqueous emulsion state using an electrically conductive substance that does not have a phase transfer catalytic ability, such as an inorganic salt, and an electrically conductive substance that has a phase transfer catalytic ability, such as a quaternary ammonium salt, respectively. Table 1 shows the selection rate of
As is clear from this table, in the case of aldehydes with a large number of carbon atoms, the effect of the presence of a conductive substance having phase transfer catalytic ability is significant. Furthermore, even the same quaternary ammonium salt has different degrees of effectiveness depending on its type. In other words, when the aldehyde has a large number of carbon atoms, it is better to use a quaternary ammonium salt with a relatively high molecular weight quaternary ammonium ion than to use a quaternary ammonium salt with a relatively low molecular weight quaternary ammonium ion. The current efficiency and yield are both improved compared to when using this method, and the influence of the size of the quaternary ammonium ion is significant. On the contrary,
In the case of aldehydes with a small number of carbon atoms, there is almost no effect of the size of the quaternary ammonium ion, but there is a slight improvement when using a quaternary ammonium salt with a relatively low molecular weight quaternary ammonium ion. is recognized. The size of the quaternary ammonium ion here refers to the quaternary ammonium salt with the general formula (In the formula, R ¹ , R ² , R ³ and R ⁴ are substitution methods for alkyl groups, aralkyl groups, etc., X is an acid group, and n is an integer that corresponds to the ionic valence of X.) is expressed as the total number of carbon atoms of R ¹ , R ² , R ³ and R ⁴ bonded to nitrogen. Furthermore, the actions of the quaternary ammonium salt as a conductive substance and as a phase transfer catalyst are generally considered as follows. In other words, quaternary ammonium salts that are generally used as substances with better conductivity are those that have high solubility in water, in other words, quaternary ammonium salts that have relatively small quaternary ammonium ions. It is a quaternary ammonium salt in which the total number of carbon atoms in R ¹ , R ² , R ³ and R ⁴ is 11 or less. However, such small quaternary ammonium ions have low phase transfer catalytic ability. On the other hand, quaternary ammonium salts with large quaternary ammonium ions, i.e., quaternary ammonium salts with a total number of carbon atoms of 12 or more, become less soluble in water as the number of carbon atoms increases. Therefore, the effect as an electrically conductive substance becomes worse as the total number of carbon atoms increases. However, such relatively large quaternary ammonium sulfur has a large phase transfer catalytic ability. Furthermore, Table 2 shows the cases in which electrolysis is performed using an inorganic salt as a conductive substance that does not have phase transfer ability, the case in which electrolysis is performed using a mixture of an inorganic salt and a conductive substance that has large phase transfer catalytic ability, and This shows a comparison between electrolysis using a mixture of a conductive substance with a small transfer catalytic function and a highly conductive substance, but in this case too, the effect is greater when using an aldehyde with a large number of carbon atoms. is remarkable. Furthermore, in the case of aldehydes with a large number of carbon atoms, it can be seen that the effect is further enhanced by the presence of a conductive substance with a large phase transfer catalytic ability.

【table】

【table】

【table】

[Table] The characteristics when the carbonyl compound is an aldehyde have been detailed above based on Tables 1 and 2.
The results shown in Table 1 can be considered to indicate that the same substance, that is, the quaternary ammonium salt, performs the function of increasing electrical conductivity and the function of a phase transfer catalyst, and the results shown in Table 2 indicate that both It can also be thought that the functions of these substances are shared by substances suitable for each function. Details of the method for producing γ-lactones, which are intermediate raw materials of the present invention, are as follows. The electrolytic reaction can be carried out by either a diaphragm method or a diaphragmless method. The diaphragmless method has advantages such as low electrolysis voltage and the possibility of simplifying the electrolytic cell. However, since oxygen is generated on the anode in proportion to the amount of current applied, and a small amount of hydrogen is generated on the surface of the cathode, there is a possibility that an explosive mixed gas may be generated. Therefore, a diaphragm method is selected in which a diaphragm is used to partition the anode chamber and cathode chamber. The diaphragm method will be explained in detail below. The electrolytic cell may be either a batch type electrolytic cell or a filter press type electrolytic cell, but generally a filter press type electrolytic cell is used. For example, in an electrolytic cell, a polyethylene plate, a diaphragm, and a polyethylene plate are placed to define the membrane-to-electrode distance so that a cathode plate and an anode plate are opposed in parallel and a cathode chamber and an anode chamber are formed between the two electrodes. These polyethylene plates have an opening in the center to allow the electrolyte to pass through. The current-carrying area of the electrode is determined by the size of the aperture, and the distance between the electrode and the membrane is determined by the thickness of the plate. The catholyte and anolyte enter through the supply ports provided in the electrolytic cell, and as they pass through the cathode chamber and the anode chamber, 1
The reacted part exits the outlet and is circulated to the catholyte tank and the anolyte tank. Examples of the cathode material include lead or an alloy containing lead as a main component, such as hard lead containing antimony, and a lead-tin alloy. These cathode materials have sufficient mechanical strength and do not cause pollution problems. It is possible to continue stable operation for a long period of time even when used in a bipolar filter press type battery case. The anode material may be any material that has sufficient corrosion resistance against the anolyte, such as lead, lead alloys,
Platinum, silver, alloys mainly composed of these metals, or other metals plated with these metals or alloys are used. As the diaphragm, a cation exchange membrane, an unglazed diaphragm, etc. can be used, but a cation exchange membrane is generally preferred. The distance between the electrode and the diaphragm is usually set at 0.5 to 3 mm. It is necessary to stir the electrolyte thoroughly in a batch type electrolytic cell. Further, in a filter press type electrolytic cell, it is preferable to set the flow rate of the electrolytic solution in the electrolytic cell to 0.2 to 4 m/sec, more preferably 1 to 4 m/sec. At flow rates lower than 0.2 m/sec, the yield decreases, and at flow rates higher than 4 m/sec, the pressure drop within the electrolytic cell becomes very large. As the anolyte, any aqueous solution of an electrically conductive acid or salt can be used, but an acidic solution is preferable in order to replenish the hydrogen ions consumed at the cathode, and an aqueous solution of an inorganic acid such as sulfuric acid or phosphoric acid is used. .
A 1 to 20% by weight aqueous sulfuric acid solution is preferred from the economical and reaction point of view. Next, we will discuss the catholyte composition, supporting electrolyte, current density, catholyte temperature, treatment of the catholyte after the electrolytic reaction, etc. However, since the carbonyl compounds of ketones and aldehydes are significantly different, we will discuss them separately. Details when the carbonyl compound is a ketone are as follows. The catholyte is a homogeneous solution consisting of ketones, acrylic esters, electrolysis products, supporting electrolytes, water, and solvents. The ketone to be used is not particularly limited, but from an industrial standpoint, aliphatic ketones having 1 to 13 carbon atoms are preferred, such as acetone, methyl ethyl ketone, and 2-octanone. The acrylic ester used is preferably a lower alkyl ester of acrylic acid from the viewpoint of solubility in water, and more preferably methyl acrylate. The solvent used is generally methanol, but in the case of acetone, it is not used because it itself acts as a solvent. The amount used may be such that the electrolyte becomes uniform. The supporting electrolyte can be an inorganic acid such as phosphoric acid or an organic acid such as para-toluenesulfonic acid, but especially sulfuric acid, as it can maintain a high electrolytic yield, increase conductivity, and at the same time increase the reactivity of ketones. is used. The sulfuric acid concentration is preferably 0.1 to 10% by weight, particularly 0.5 to 5% by weight. If it is less than 0.1%, the electrolytic voltage will be high. If it exceeds 10% by weight, hydrolysis of acrylic acid methyl ester will increase and the yield will decrease. A high yield is shown when the current density is 1 to 5 A/ ^dm2 , the yield decreases at a current density higher than 5 A/ ^dm2 , and the productivity worsens at a current density of less than ¹ A/dm2.
It is necessary to increase the current carrying area. High material yield and current efficiency are exhibited when the acrylic ester concentration in the electrolyte is in the range of 1.0 to 4.0% by weight. 1.0
Below 4.0 wt%, the current efficiency decreases
Above that, the material yield decreases due to hydrolysis and the like.
Furthermore, the current density is more preferably 1 to 3 A/dm ² , and if it is 3 A/dm ² or more, the yield will decrease slightly. The acrylic ester concentration is more preferably in the range of 1.0 to 3.0% by weight, and if the concentration is higher than 3.0% by weight, the yield will decrease slightly. The temperature of the catholyte is preferably 30° C. or higher and lower than the boiling point of the solvent in terms of yield and electrolytic voltage. That is, below 30°C, the yield decreases and the voltage also increases. From the viewpoint of yield, the temperature is preferably 40°C or higher. The electrolytic reaction method is preferably a batch reaction in which the acrylic ester is consumed from the viewpoint of liquid purification after the reaction is completed. However, if the acrylic acid ester concentration is 4% by weight or more, the yield decreases, and if the yield is to be maintained, the productivity will decrease. Further, if the amount is less than 1% by weight, the current efficiency decreases. In this way, high current efficiency and high productivity cannot be obtained in a batch reaction in which the acrylic ester charged at one time is consumed before the start of the reaction. Therefore, acrylic ester is added continuously or intermittently for a certain period of time to maintain the acrylic ester concentration in the range of 1.0 to 4.0% by weight, and then the addition of acrylic ester is stopped to consume the remaining acrylic ester. More preferred is a method with high current efficiency, high yield, and good productivity, in which the electrolytic reaction is carried out until As a method for separating and purifying γ-lactone from the electrolytic solution after the completion of the electrolytic reaction, it can be separated and purified by direct distillation, but it is preferable to directly contact the electrolytic solution with an alkali, and then separate and purify it by distillation after neutralization. More preferably, by contacting the electrolyte with an excess alkali aqueous solution of 10 to 50% by weight, the aqueous layer containing the alkali and the organic layer containing the γ-lactone are separated into two layers, and the water containing the alkali is separated into two layers, an aqueous layer containing an alkali and an organic layer containing γ-lactone. The layer is reused, and γ-lactone is separated and purified from the organic layer by distillation. If the electrolyte is directly distilled,
Material corrosion of the distillation column occurs due to sulfuric acid. Furthermore, the desired product, γ-lactone, is lost due to polymerization and the like. If the alkali concentration is less than 10% by weight, the product will not separate into two layers, an aqueous layer and an organic layer, and if there is an excess of alkali, the γ-lactone will open as a result of heating during distillation and become a salt, resulting in loss. Additionally, salts precipitate within the distillation column, making distillation operations difficult. When it exceeds 50% by weight, hydrolysis of γ-lactone occurs. As the alkali, hydroxides such as sodium, potassium, and calcium can be used, but
Sodium hydroxide is preferred in terms of solubility and cost. Details of the case where the carbonyl compound is an aldehyde will be described. The catholyte contains the reactant acrylic ester,
It is a mixture of substances derived from reactants such as aldehydes and their electrolyzed products such as γ-lactone, adipic acid diester, propionic acid ester, and alcohol, water, and a conductive substance to increase conductivity. It exists as a two-phase system with an oil phase. In some cases, it is also possible to add an acrylic acid ester polymerization inhibitor, and to stabilize the emulsion, an emulsifier or the like may be used, and a solvent may be added as long as it does not adversely affect emulsion formation. Although it is possible to add these additives or solvents, it is usually preferable to perform electrolysis without using these additives or solvents. The aldehyde used is
Although not particularly limited, industrially preferred are aliphatic aldehydes, aromatic aldehydes, and araliphatic aldehydes having 1 to 13 carbon atoms, and more preferred are saturated straight-chain aliphatic aldehydes. Examples include propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal, and aldehydes having side chains thereof.
The acrylic ester used is preferably a lower alkyl ester of acrylic acid from the viewpoint of solubility in water, and most preferably acrylic acid methyl ester, which is inexpensive and industrially easily available. The molar ratio of aldehyde to acrylic ester is preferably 1/2 to 10 from the viewpoint of yield, and more preferably 1 to 5 from the viewpoint of product separation. The amount of aldehyde and acrylic ester relative to water may be at least the amount dissolved in water and at least the amount at which the organic phase separates and an emulsion is formed. The volume ratio of the organic phase in the emulsion to the total emulsion is 0.05 for ease of product separation.
~0.5 is preferred. As a quaternary ammonium salt used as a conductive substance having phase transfer catalytic ability, for example, the general formula There is a compound represented by the formula (R ¹ , R ² , R ³ , R ⁴ , X and n have the same meanings as above). When this quaternary ammonium salt is used alone, it is necessary to use one that has both the function of imparting electrical conductivity and the function of a phase transfer catalyst. In addition, in electrolysis using aldehydes with a small number of carbon atoms, such as aldehydes with 1 to 4 carbon atoms, there is no particular difference in current efficiency and selectivity depending on the type of quaternary ammonium salt; Any quaternary ammonium salt having quaternary ammonium ions having a sum of 4 to 20 can be used. However, in terms of the function of increasing electrical conductivity, the total number of carbon atoms in R ¹ , R ² , R ³ and R ⁴ is 4 to 16
Quaternary ammonium salts with relatively small quaternary ammonium ions are preferred. This quaternary ammonium salt usually has R ¹ , R ² ,
Those in which R ³ and R ⁴ are alkyl groups selected from the group consisting of methyl, ethyl, propyl and butyl groups are preferably used. Examples of such quaternary ammonium salts include tetramethylammonium salt, tetraethylammonium salt,
Examples include tetra(n or iso)-propylammonium salt, tetra-(n or iso)-butylammonium salt, ethyltrimethylammonium salt, diethyldimethylammonium salt, methyltriethylammonium salt, propyltriethylammonium salt, propyltrimethylammonium salt, etc. It will be done. In addition, in electrolysis using aldehydes with a large number of carbon atoms, for example, aldehydes with 5 to 13 carbon atoms,
R ¹ , R ² , R ³ and R ⁴ in terms of current efficiency and selectivity
A quaternary ammonium salt having a relatively large quaternary ammonium ion with a total number of carbon atoms of 12 to 20, that is, a quaternary ammonium salt that has a relatively large phase transfer catalytic ability and does not significantly reduce the electrical conductivity. It is preferable to use As such a quaternary ammonium salt, one in which at least three of R ¹ , R ² , R ³ and R ⁴ are an alkyl group having 3 or more carbon atoms is generally suitable. Such substances include, for example, tetra(n or iso)-propylammonium salt, tetra(n or iso)
-butylammonium salt, tetra-(n or
iso)-amylammonium salt, dipropyldibutylammonium salt, ethyltripropylammonium salt, ethyltributylammonium salt, ethylpropyldibutylammonium salt, and the like. Among these, those having an alkyl group of a propyl group or a butyl group are more preferable, and those having a tetrabutyl group are particularly easy to obtain industrially. These quaternary ammonium salts may be used alone or in combination of two or more,
Furthermore, a conductive substance whose cation is an inorganic cation may be used in combination. When using a quaternary ammonium salt as one of such mixed systems with other types of conductive substances, there are two types of quaternary ammonium salts: one that primarily functions to increase electrical conductivity, and one that primarily functions as a phase transfer catalyst. It is preferable to use them separately. That is, when using a mixture of quaternary ammonium salts, it is recommended to use one type that has a large effect of increasing electrical conductivity, and the other type that has a large effect of phase transfer catalytic ability. preferable.
In addition, when a quaternary ammonium salt and an inorganic salt as a conductive substance are mixed and used, the inorganic salt has the function of increasing conductivity, so the quaternary ammonium salt has a strong phase transfer catalytic ability. Preferably, salt is used. As mentioned above, quaternary ammonium salts that have a large effect of increasing electrical conductivity are especially
A quaternary ammonium salt having a relatively small quaternary ammonium ion in which the total number of carbon atoms of R ¹ , R ² , R ³ and R ⁴ is 4 to 11 is preferable, and among them,
Preferably, R ¹ , R ² , R ³ and R ⁴ each have an alkyl group of 3 or less carbon atoms, and more preferably R ¹ , R ² ,
More preferably, R ³ and R ⁴ are all ethyl groups. Examples of quaternary ammonium salts that greatly enhance conductivity include tetraethylammonium sulfate, tetramethylammonium sulfate, tetraethyl-p-toluenesulfonate, tetraethylammonium chloride,
Examples include methyltriethylammonium chloride. On the other hand, quaternary ammonium salts with high phase transfer catalytic ability are particularly suitable for R ¹ , R ² , R ³ and R ⁴ as mentioned above.
A quaternary ammonium salt having a relatively large quaternary ammonium ion having a total number of carbon atoms of 12 to 30 is preferred, such as tetra-t-butylammonium sulfate,
Tetra-n-amylammonium sulfate,
Tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, penzyltriethylammonium chloride, benzyltripropylammonium chloride, benzyltributylammonium chloride, hexadecyltrimethylammonium bromide, hexadecylethyldimethylammonium bromide,
Examples include methyltricaprylammonium chloride. Among these, quaternary ammonium salts used as phase transfer catalysts, such as tetra-n-butylammonium salt and benzyltripropylammonium salt, in which the respective alkyl groups and aralkyl groups are similar in size are preferred. If only one of these groups has a fairly long chain, a surfactant effect will appear and the separation of the product γ-lactones will be complicated. Next, as the counter anion X of the quaternary ammonium salt, for example, sulfate ion, p-toluenesulfonate ion, phosphate ion, halogen ion, hydrogen sulfate ion, hydrogen phosphate ion, dihydrogen phosphate ion, etc. are used. However, as described below, there is no problem with quaternary ammonium salts having halogen ions as counteranions when used in an amount sufficient to provide phase transfer catalytic ability, but when used in large amounts to increase conductivity. is not very favorable for electrodes. Therefore, sulfate ion, p-toluenesulfonate ion, phosphate ion, hydrogen sulfate ion, hydrogen phosphate ion, or dihydrogen phosphate ion is usually used as a preferable counter anion. There is no particular restriction on the amount of quaternary ammonium salt used, if it is used for the purpose of increasing conductivity, as long as the emulsion does not have a large electrical resistance at the mold edges and electrolysis can be carried out smoothly. It is desirable to use it so that the concentration in the aqueous phase is in the range of 2 to 30% by weight. In addition, when used for the purpose of providing a function as a phase transfer catalyst, from the viewpoint of economy and selectivity of γ-lactone, the amount of It is preferable to use Further, when it is used for both the purpose of increasing electrical conductivity and as a phase transfer catalyst, it is sufficient to use the same amount as when it is used for the purpose of increasing electrical conductivity. Further, examples of the quaternary ammonium salts used include, for example, tetra-n-butylphosphonium bromide, triphenylmethylphosphonium iodide, tetraphenylphosphonium chloride, and the like. Although these quaternary ammonium salts can be used alone, they are generally used for the purpose of phase transfer catalysts, and are not often used for the purpose of increasing electrical conductivity. It is preferable to use it in combination with an electrically conductive substance containing an inorganic cation or an inorganic cation. The amount used is preferably in the range of 0.1 to 50 mol % based on whichever is smaller of the aldehyde or the acrylic ester from the viewpoint of economy and selectivity of γ-lactone. In addition to the above-mentioned quaternary ammonium salts and quaternary phosphonium salts, which have both the phase transfer catalytic ability and the function of increasing electrical conductivity, phase transfer catalysts such as crown ethers and cryptands do not have the function of increasing electrical conductivity, but also have the function of increasing electrical conductivity. When used only for transfer catalytic ability, almost the same effect is observed, but these are difficult to obtain industrially and difficult to recover from the electrolyte, making them impractical. Furthermore, when comparing quaternary ammonium salts and quaternary phosphonium salts, quaternary ammonium salts can be obtained industrially at lower cost, and there is no risk of wastewater pollution. It is more preferable to use salt. In terms of the yield of γ-lactone, the conductive substances that use inorganic cations are as follows:
H ₂ SO ₄ , MHSO ₄ , M ₂ SO ₄ , MH ₂ PO ₄ and H ₃ PO ₄
(However, M is an alkali metal.) Preferably, at least one inorganic substance selected from the group consisting of:
There is no particular restriction on the amount used, as long as the electrical resistance of the emulsion is not extremely high and electrolysis can be carried out smoothly, and the concentration in the aqueous phase is usually 2 to 30.
It is used so that it falls within the range of % by weight. The current density on the cathode surface is 1A/dm ² ~
50 A/dm ² is preferred. ^Below 1A/dm2, productivity decreases and electrodes with a wide area are required;
If it is more than ^m2 , heat generation due to liquid resistance is severe and it is not practical. It is usually carried out at 5 to 20 A/dm ² . The temperature of the catholyte may be any temperature as long as it is below the boiling temperature of the aldehyde or acrylic ester, but it is usually preferably 20 to 60°C, particularly 20 to 40°C, in order to prevent thermal denaturation of the aldehyde and acrylic ester. Treatment of the catholyte after the electrolytic reaction is normally performed as follows. That is, first, the electrolytic solution is separated into two layers, an oil layer and an aqueous layer, and then the conductive substance distributed in the oil layer is extracted with a small amount of water. The oil layer is then distilled, first removing low-boiling byproducts such as methanol, then recovering unreacted raw materials, and then obtaining the product. On the other hand, for the aqueous layer, low-boiling byproducts such as methanol are removed by distillation, water corresponding to the water transferred from the anolyte is removed by distillation, and the remaining liquid containing conductive substances is transferred to the cathode. It is used for circulation as a liquid aqueous layer. In the method of the present invention, products can be separated very easily through such treatment, and electrically conductive substances can also be collected very easily. Details of the method of the present invention for producing 2-cyclopentenones by dehydration condensation of γ-lactones are as follows. The γ-lactone used can be obtained by the method described above. That is, when a ketone is used as the carbonyl compound, γ-dialkyl-γ-butyrolactone is obtained, and when an aldehyde is used, γ-monoalkyl-γ-butyrolactone is obtained. Depending on the type of ketone and aldehyde used, the alkyl substituent may be a linear one or one with a side chain, and either can be used. Furthermore, as the alkyl substituent, those having 1 to 10 carbon atoms are generally used, but from the viewpoint of yield, those having 2 or more carbon atoms, and more preferably 3 or more carbon atoms, are used. Further, when applied to γ-monoalkyl-γ-butyrolactone, the improvement in yield is particularly favorable. Furthermore, there are the following differences in reactivity between γ-dialkyl-γ-butyrolactone and γ-monoalkyl-γ-butyrolactone. That is, γ
-Monoalkyl-γ-butyrolactone has a faster reaction rate than γ-dialkyl-γ-butyrolactone under the same reaction conditions, but as the conversion rate of the raw material increases, the selectivity to the product decreases.
In order to maintain high selectivity, it is necessary to keep the conversion rate below 50%. On the other hand, γ-
Although the reaction rate of di-γ-alkyl-γ-butyrolactone is slower than that of γ-monoalkyl-γ-butyrolactone, the selectivity to the product does not decrease much even if the conversion rate of the raw material increases. A similar difference in reactivity was observed with respect to the number of carbon atoms in the alkyl substituent.
For materials with a small number of carbon atoms, particularly those with a carbon number of 3 or less, it is preferable to suppress the conversion rate of the raw material to 50% or less. The solvent used is an inert solvent that does not dissolve in water, but from the viewpoint of solubility and yield of the raw material γ-lactone, the product 2-cyclopentenone, and the catalyst sulfonic acid, toluene,
Aromatic hydrocarbons such as xylene, mesitylene, tetralin, and alkyl-substituted diphenyl are preferred.
The amount of solvent used is 5 to 100 parts by weight per 1 part by weight of γ-lactone as a raw material. If the amount of solvent is less than 5 parts by weight, the yield will deteriorate rapidly, which is not preferable. When the amount is more than 100 parts by weight, there is no problem in terms of yield, but it is difficult to remove the solvent, which is not preferable. The catalyst used is p-toluenesulfonic acid,
β-naphthalenesulfonic acid, methanesulfonic acid,
A sulfonic acid catalyst such as trifluoromethanesulfonic acid. The catalysts may be used alone or in combination. From the viewpoint of yield, it is preferable that the catalyst be used in a state dissolved in a solvent, that is, in a homogeneous state, at least during the reaction. That is, sulfonic acids that completely dissolve in the solvent at the reaction temperature are preferred, and the above-mentioned sulfonic acids correspond. On the other hand, catalysts that are insoluble in solvents, such as sulfonic acid type strongly acidic cation exchange resins, have problems in terms of reaction rate and do not provide sufficient yields. The amount of catalyst used is 0.2 to 0.2 to γ-lactone as the raw material.
A range of 5 times the mole is preferred. Furthermore, in the case of a highly acidic catalyst such as trifluoromethanesulfonic acid, it is more preferable to use a slightly smaller amount of 0.2 to 2 times the mole in terms of reaction rate and yield. On the other hand, in the case of a catalyst such as p-toluenesulfonic acid, it is preferable to use equal moles or more. The reaction is preferably carried out at a temperature range of 90°C or higher and 230°C or lower. Furthermore, it is desirable to conduct the heating at a temperature of 110°C or higher and 200°C or lower. At temperatures lower than 90°C, the reaction rate is slow and the reaction does not substantially proceed.
That is, in the reaction of the present invention, water is produced as the reaction progresses, and it is necessary to remove this water from the reaction system, and for this purpose, a temperature of 90° C. or higher is preferable. Further, at a temperature higher than 230°C, the reaction rate becomes extremely high, but the selectivity of the reaction deteriorates, which is not preferable. Furthermore, when the raw material γ-lactone has a small number of carbon atoms in the alkyl substituent, particularly one having 3 or less carbon atoms, a temperature of 130° C. or higher, more preferably 150° C. or higher is preferable from the viewpoint of yield. The reaction solution may be treated by a conventional method.
That is, the product 2-cyclopentenone can be easily obtained by first treating the reaction solution with water to remove the sulfonic acid catalyst, then distilling the solvent, and then distilling the residual liquid under reduced pressure. . The sulfonic acid catalyst extracted into the aqueous layer can be used again for the reaction, and the unreacted raw material γ-lactone remains in the residual liquid after the product is isolated by distillation.
It is possible to use the residual liquid as it is in the reaction again, and in some cases, it is also possible to further isolate γ-lactone from the residual liquid by vacuum distillation and use it in the reaction again. As described in detail above, the method of the present invention has the following advantages over various conventionally proposed methods, and is extremely industrially advantageous. That is, firstly, the reaction can be carried out under relatively mild conditions, and the catalyst can be recovered and reused very easily. Secondly, according to the method of the present invention, the desired product can be obtained in extremely high yield. Especially γ
In the case of -monoalkyl-γ-butyrolactone, the effect is remarkable compared to the conventional method. Thirdly, especially in the case of γ-monoalkyl-γ-butyrolactone, 2-cyclohexenone can be obtained as a by-product in addition to the desired product 2-cyclopentenone, and this substance is also used in fragrances and pharmaceuticals. It is extremely important industrially as a starting material for agricultural chemicals, etc.
Fourthly, by selecting a method of electroreductive cross-dimerization of an acrylic acid ester and a carbonyl compound as a method for producing γ-lactone, 2-cyclopentenone can be produced more advantageously. It became. EXAMPLES Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way. However, the current efficiency was determined by the following formula on the assumption that 1 mole of γ-lactones is produced by the amount of electricity of 2 Faradays. Γ Current efficiency = Number of moles of γ-lactones produced x 2/Amount of current applied (Falladay unit) x 100 (%) In addition, the reaction rate, selectivity, and amount of current applied relative to theory shall comply with the following definitions. Γ Reaction rate of acrylic ester = Number of moles of acrylic ester consumed / Number of moles of acrylic ester charged × 100 (%) Γ Reaction rate of carbonyl compound = Number of moles of carbonyl compound consumed / Number of moles of charged acrylic ester Number of moles of compound × 100 (%) Γ Selectivity of γ-lactones based on acrylic ester = Number of moles of γ-lactones produced / Number of moles of acrylic ester consumed × 100 (%) Γ Carbonyl compound Standard selectivity of γ-lactones = Number of moles of γ-lactones produced/Number of moles of carbonyl compound consumed × 100 (%) Γ vs. theoretical energization amount = Actual energization amount (Faraday units)/Prepared Number of moles of acrylic ester × 2 × 100 (%) Γ Selectivity of alcohol produced by reduction of carbonyl compound = Number of moles of alcohol produced / Number of moles of carbonyl compound consumed × 100 (%) Γ Propion Acid ester selectivity = Number of moles of propionate ester produced/Number of moles of acrylate ester consumed × 100 (%) Γ Selectivity of adipic acid ester = Number of moles of adipate ester produced × 2/Consumption Number of moles of acrylic acid ester x 100 (%) Example 1 Both the anode and cathode were made of lead with a current-carrying area of 0.58 dm ² and a divinylbenzene-styrene-thickness of 1.6 mm.
A cation exchange membrane obtained by sulfonating a butadiene copolymer is used to partition the anode chamber and cathode chamber.
An electrolytic device was used in which a cell was provided with an anolyte tank and a catholyte tank in which the distance between the membrane and the electrode was maintained at 2 mm using a polyethylene spacer, and the liquid could be circulated between the cell and the cell. The catholyte contained 73.9 g (0.648 mol) of heptanal, 18.6 g (0.216 mol) of methyl acrylate, 418 g of water, 53 g of tetraethylammonium sulfate, and tetra-n.
- A mixture of 36 g of butylammonium sulfate was used. Maintain the catholyte temperature at 27-29℃ and adjust the flow rate
The catholyte was circulated between the cell and the catholyte tank at 200 cm/sec, the current density was set at 10.0 A/ ^dm2 , and during electrolysis, 45.9 g of heptanal (0.403
mol) and methyl acrylate 48.8g (0.567 mol)
The mixture was continuously supplied to the catholyte tank for 5 hours and electrolyzed, and the electrolysis was terminated when the theoretical energization amount reached 66%. The voltage varied from 5.8V to 5.9V. After the electrolysis was completed, the electrolytic solution was separated into two layers, and the oil layer was washed with 50 g of water and then distilled. 10g of methyl acrylate was recovered from the oil and water layers, and 66g of heptanal was recovered from the oil layer. Furthermore, 57 g of γ-decalactone was obtained from the oil layer by distillation, and 22 g of dimethyl adipate, a by-product, was also obtained.
That is, the reaction rate of methyl acrylate is 85%, the reaction rate of heptanal is 5%, and the selectivity of γ-decalactone is 50% based on methyl acrylate.
%, which was 70% based on heptanal, and the current efficiency was 65%. Furthermore, the selectivity of dimethyl adipate was 39%. Next, a dehydration condensation reaction was carried out using the γ-decalactone obtained by the above method. That is, 200 g of p-toluenesulfonic acid was placed in a four-necked flask equipped with a thermometer, a stirrer, and a condenser.
and 1000 g of p-xylene were added and the temperature was raised until the p-xylene refluxed, and then the water that had refluxed with the p-xylene was distilled off along with a small amount of p-xylene. Next, 50 g of γ-decalactone was placed in the flask, the internal temperature was raised to 138°C, and the flask was stirred for 0.5 hour while the produced water was distilled off along with a small amount of p-xylene. The total amount of p-xylene and water distilled off was 27 g. After the reaction was completed, 700 g of water was added to the reaction solution to extract p-toluenesulfonic acid.
The oil layer weighs 1020 g, p-xylene is distilled off from this oil layer, and the resulting residual liquid is distilled under reduced pressure to obtain 2-
2.0g each of n-butyl-2-cyclohexenone, 2-n-pentyl-2-cyclopentenone, and γ-decalactone (boiling point 70℃/3.5mmHg), 6.5g
g (boiling point 80℃/3.0mmHg) and 38g (boiling point 125
°C/3.5mmHg). The conversion rate of γ-decalactone was 24%, and the selectivity of 2-n-pentyl-2-cyclopentenone was 60%. Note that 2-n-pentyl-2-cyclopentenone and 2-n-butyl-2-cyclohexenone were confirmed by infrared absorption spectrum (IR), nuclear magnetic resonance spectrum (NMR), and weight spectrum (Mass). 2-n-pentyl-2-cyclopentenone IR (liquid film): 1700, 1630 cm ^-1 NMR (CDCl ₃ ): δ (ppm), 0.7-1.8 (9H),
1.8-2.8 (6H), 7.3 (1H) Mass: m/e152 (M ⁺ ) 2-n-butyl-2-cyclohexenone IR (liquid film): 1675, 1630 cm ^-1 NMR (CDCl ₃ ): δ (ppm ), 0.7~1.8 (7H)
1.8 to 2.8 (8H), 6.7 (1H) Mass: m/e152 (M ⁺ ) Example 2 The same electrolytic cell and anolyte as in Example 1 were used.
The catholyte contained 46.8 g (0.650 mol) of butanol, 19.2 g (0.223 mol) of methyl acrylate, and water.
456g, tetraethylammonium sulfate
78g of the mixture was used. Catholyte temperature 28~30℃
The catholyte was circulated and stirred between the battery cell and the catholyte tank at a flow rate of 200 cm/sec, and the current density was increased.
Set at 10.0A/dm ² and during electrolysis, butanal
34.6g (0.481mol) and 36.7g methyl acrylate
(0.427 mol) was electrolyzed while being continuously supplied to the catholyte tank for 5 hours. Even after the supply was finished, electrolysis was continued, and the electrolysis was terminated when the energization amount relative to theory reached 118%. The voltage varied from 5.4 to 5.6V. After electrolysis is complete, remove the electrolyte and
The layers were separated and the oil and water layers were analyzed by gas chromatography. As a result, the reaction rate of methyl acrylate was 99%, that of butanal was 76%, and γ
- Selectivity of heptalactone is 85% based on methyl acrylate and 63% based on butanal,
The current efficiency was 71%. Note that the selectivity of dimethyl adipate was 1% or less. Next, the oil layer was separated, and γ-heptalactone was obtained by distillation, followed by a dehydration condensation reaction. i.e. 200 equipped with thermometer, stirrer and condenser.
15 mL of p-toluenesulfonic acid in a four-necked flask.
Add 100g of g and p-xylene and heat under reflux.
Water was distilled off along with a small amount of p-xylene. Next, 5 g of γ-heptalactone was placed in a four-necked flask and heated under reflux for 0.5 hour. During heating under reflux, the water produced was distilled off along with a small amount of p-xylene. The total amount of p-xylene and water distilled off was 3.5 g. Next, the same post-treatment as in Example 1 was carried out, and the oil layer was
Obtained 101g. The concentration of γ-heptalactone in the oil layer was 3.86% by weight, and the concentration of 2-n-propyl-2-cyclopentenone was 0.57% by weight. In other words, the conversion rate of γ-octalactone is 22%, and 2
-The concentration of n-propyl-2-cyclopentenone is
It was 60%. Example 3 A mixed solution of 303 g of 2-octanone, 9.0 g of methyl acrylate, 6.2 g of 97% sulfuric acid, 47.8 g of water, and 234 g of methanol was used as a catholyte and charged into a catholyte tank. 1 kg of 10% sulfuric acid aqueous solution in the anolyte tank
I prepared it. The catholyte and anolyte are circulated to the electrolytic cell. The electrolytic cell has a current-carrying area of ^0.55dm2 for both poles,
The cathode is a 4 mm thick lead plate, the anode is a 4 mm thick hard lead plate (containing 5% antimony), and the electrode is 2 mm thick with an opening so that the current carrying area is 0.55 dm ² . A cathode chamber and an anode chamber were formed using two polyethylene plates and a cation exchange membrane obtained by sulfonating a divinylbenzene-styrene copolymer with a thickness of 1.6 mm. The electrolytic cell has an electrolyte supply inlet and an outlet. The electrolytic solution was flowed at a flow rate of 2 m/sec, and when the solution temperature reached 60° C., the electrolytic reaction was started at a current density of 2 A/dm ² . Simultaneously with the start of the reaction, methyl acrylate was continuously added,
The concentration of methyl acrylate in the electrolyte was kept constant. The continuous addition amount was 18.0g. After the addition was completed, the electrolytic reaction was carried out until the concentration of methyl acrylate in the electrolytic solution became 0.1% by weight or less. γ-Methyl-γ-decalactone and methyl acrylate in the electrolyte were analyzed by gas chromatography.
As a result, the material yield during continuous addition of acrylic acid methyl ester was 91.0%, the current efficiency was 76.0%, the material yield from the stop of addition until the end of the reaction was 90.9%, the current efficiency was 65.1%, and the material yield from the start to the end of the reaction was 91.0%. The yield is
The current efficiency was 91.0% and 72.4%. Next, 59 g of water was added to the electrolytic solution to separate into an oil-water layer, and then a 50% by weight sodium hydroxide solution was added to the oil layer to neutralize the sulfuric acid in the oil layer, and the electrolyte was separated into two oil-water layers. The solvent and the like were removed from the oil layer, and γ-methyl-γ-decalactone was obtained by distillation. Next, a dehydration condensation reaction was carried out using the γ-methyl-γ-decalactone obtained by the above method. That is, using the same reaction apparatus as in Example 2, 13 gr of p-toluenesulfonic acid and 120 gr of p-xylene were placed in a four-necked flask and heated under reflux to distill off water along with a small amount of xylene. Next, 3 grams of γ-methyl-γ-decalactone was placed in a four-necked flask and heated under reflux for 5 hours. During heating under reflux, the water produced was distilled off along with a small amount of p-xylene. The total amount of p-xylene and water distilled off was 9 gr. Next, 50g of water was added to the reaction solution to extract p-toluenesulfonic acid, yielding 113g of an oil layer. γ-methyl-γ in oil layer
-The concentration of decalactone was 1.14% by weight and the concentration of dihydrdiasmone was 1.30% by weight. γ
The conversion rate of -methyl-γ-decalactone was 57%, and the selectivity of dihydrdiasmone was 95%. Example 4 A mixed solution of 77.5 g of methyl acrylate, 2.527 g of acetone, 32 g of 97% sulfuric acid, and 464 g of water was used as a catholyte and charged into a catholyte tank. The anolyte tank was charged with 3 kg of 10% sulfuric acid aqueous solution. The catholyte and anolyte are then circulated into the electrolytic cell. The electrolytic cell has a current-carrying area of 2 dm ² with both electrodes measuring 2 cm x 100 cm, the cathode is a lead plate with a thickness of 4 mm, and the anode is a lead plate with a thickness of 4 mm.
Using a plate of mm hard lead (containing 5% antimony),
Two 2 mm thick polyethylene plates with holes so that the current carrying area is 2 dm ² between the two electrodes and 1.6 mm thick
A cathode chamber and an anode chamber were formed using a cation exchange membrane obtained by sulfonating a divinylbenzene-styrene copolymer of mm. The electrolytic cell has an electrolyte supply inlet and an outlet. The electrolytic solution was flowed at a flow rate of 2 m/sec, the solution temperature was raised to 45° C., and the electrolytic reaction was started at a current density of 2 A/dm ² . Simultaneously with the start of the reaction, methyl acrylate was continuously added to keep the methyl acrylate concentration in the electrolyte constant. The continuous addition time was 15 hours, and the amount added was 81.0 g. Even after the addition was completed, the electrolytic reaction continued to consume acrylic acid methyl ester. When the concentration of each component of the electrolytic solution after the electrolytic reaction was determined by gas chromatography analysis, the concentration of γ,γ-dimethyl-γ-butyrolactone was 6.2% by weight and the concentration of methyl acrylate was 0.02% by weight. This is the current efficiency of γ,γ-dimethyl-γ-butyrolactone production.
82.0%, and the material yield is 91.0%. After the electrolytic reaction is complete, transfer the electrolyte to a tank equipped with stirring equipment, and add excess 50% sodium hydroxide aqueous solution.
300g was charged and stirred to neutralize the electrolyte. Next, the mixture was sent to a decanter and separated into two layers: an aqueous layer containing sodium hydroxide and an organic layer containing γ,γ-dimethyl-γ-butyrolactone. The aqueous layer was circulated to the neutralization tank. The organic layer was sent to a distillation column. Purification of γ,γ-dimethyl-γ-butyrolactone was performed by batch distillation. In batch distillation, low-boiling substances such as acetone were first removed, and then γ,γ-dimethyl-γ-butyrolactone was distilled out. The distilled amount was 181 g. Next, a dehydration condensation reaction was carried out using γ,γ-dimethyl-γ-butyrolactone obtained by the above method. That is, using the same reaction apparatus as in Example 2, p-toluenesulfonic acid was placed in a four-necked flask.
Add 13.4g and 36.5g of mesitylene and heat under reflux.
Water was distilled off along with a small amount of mesitylene. Next, 3g of γ,γ-dimethyl-γ-butyrolactone was placed in a four-necked flask and heated under reflux for 30 minutes. During heating under reflux, the water produced was distilled off along with a small amount of mesitylene. The total amount of mesitylene and water distilled off was 4 gr. Next, 110g of water was added to the reaction solution to separate it into an oil-water layer. Next, add 30g of chloroform to the aqueous layer.
Extracted twice. The total amount of oil layer was 128 gr. The concentration of γ,γ-dimethyl-γ-butyrolactone in the oil layer was 1.95% by weight, and the concentration of 3-methyl-2-cyclopenten-1-one was 0.23% by weight. The conversion rate of γ,γ-dimethyl-γ-butyrolactone was 17%, and the selectivity of 3-methyl-2-cyclopenten-1-one was 68%. Example 5 Both the anode and cathode were made of lead with a current-carrying area of 0.0431 dm ² and divinylbenzene-styrene with a thickness of 1.6 mm.
An H-type cell partitioned into an anode chamber and a cathode chamber by a cation exchange membrane obtained by sulfonating a butadiene copolymer was used as an electrolytic cell. As an anolyte
10% sulfuric acid was used. As catholyte, heptanal 8.61g (75.5m
mol), methyl acrylate 2.20g (25.6m mol),
A mixture of 52.0 g of water, 6.23 g of tetraethylammonium sulfate and 1.00 g of tetra-n-butylammonium sulfate was used as a conductive material. Electrolysis was carried out at a current density of 10.2 A/dm ² while maintaining the temperature of the catholyte at 28 to 29° C. and thoroughly stirring with a magnetic stirrer. The theoretical current flow is
When the electrolysis reached 105%, the electrolysis was terminated and the catholyte was analyzed by gas chromatography, and the reaction rate of methyl acrylate was 93% and the reaction rate of heptanal was 24%.
%, the selectivity of γ-decalactone is 63% based on methyl acrylate, 83% based on heptanal, current efficiency is 56%, selectivity of 1-heptanal is 11%,
The selectivity for methyl propionate was 9% and the selectivity for dimethyl adipate was 28%. The above electrolytic reaction was repeated, and the resulting electrolytic solution was treated in the same manner as in Example 1 to obtain γ-decalactone. Next, a dehydration condensation reaction was performed using γ-decalactone. That is, using the same reaction apparatus as in Example 1, p-toluenesulfonic acid was placed in a four-necked flask.
110 g of p-xylene and 1020 g of p-xylene were added, and the temperature was raised until the p-xylene refluxed, and then the water that had refluxed with the p-xylene was distilled off along with a small amount of p-xylene. Next, 25 g of γ-decalactone was placed in a flask and heated under reflux, and the mixture was stirred for 1.7 hours while the produced water was distilled off along with a small amount of p-xylene. The total amount of p-xylene and water distilled off was 25 g. After the reaction was completed, 52 g of water was added to the reaction solution, and the mixture was cooled and separated into two layers. The oil layer weighs 1028 g, and the concentration of γ-decalactone in the oil layer is 2.02% by weight, the concentration of 2-n-pentyl-2-cyclopentenone is 0.24% by weight, and the concentration of 2-n-butyl-2-cyclohexenone is It was 0.07% by weight. In other words, the conversion rate of γ-decalactone is 17%, and the conversion rate of γ-decalactone is 17%.
The selectivity of n-pentyl-2-cyclopentenone is
It was 65%. Next, the reaction was carried out again using 125 g of the separated and collected aqueous layer. That is, using the same reaction apparatus as above, 930 g of p-xylene was collected by distillation from 125 g of the water layer and the oil layer in a four-necked flask.
was added, and the water that had refluxed together with p-xylene was distilled off by the same operation as above. Next, 23g of γ-decalactone was placed in a flask and heated under reflux.
The mixture was stirred for 1.5 hours while the produced water was distilled off along with a small amount of p-xylene. The total amount of p-xylene and water distilled off was 24 g. After the reaction was completed, 47 g of water was added to the reaction solution to separate two layers. Oil layer is 939
g, and the concentration of γ-decalactone in the oil layer is
2.03% by weight, the concentration of 2-n-pentyl-2-cyclopentenone is 0.23% by weight, 2-n-butyl-2
-The concentration of cyclohexenone was 0.07% by weight. In other words, the conversion rate of γ-decalactone is 17%.
The selectivity for 2-n-pentyl-2-cyclopentenone was 62%. Example 6 Using the same electrolytic cell and anolyte as in Example 5, 8.71 g (76.4 m
mol), methyl acrylate 2.18g (25.4m mol),
A mixture of 57.6 g of water and 9.99 g (17.2 mmol) of tetra-n-butylammonium sulfate was used. Keep the temperature of the catholyte at 28 to 29℃ and stir thoroughly with a magnetic stirrer to increase the current density.
Electrolysis was performed at 10.2 A/dm ² . The theoretical current flow is
When the electrolysis reached 105%, the electrolysis was terminated and the catholyte was analyzed by gas chromatography.The reaction rate of methyl acrylate was 97% and the reaction rate of heptanal was 20%.
%, the selectivity of γ-decalactone is 56% based on methyl acrylate, 91% based on heptanal, the current efficiency is 52%, and the selectivity of 1-heptanal is 2.
%, the selectivity for methyl propionate was 15% or less, and the selectivity for dimethyl adipate was 28%. Next, γ-decalactone was obtained in the same manner as in Example 5, and then a dehydration condensation reaction was performed. That is, using the same reaction apparatus as in Example 2, 15 g of p-toluenesulfonic acid and 100 g of toluene were placed in a four-necked flask.
was added and heated, and the water that had azeotroped with toluene was distilled off. Next, 4 g of γ-decalactone was placed in a four-necked flask and heated under reflux for 10 hours. During the reflux heating, the water produced was distilled out of the system together with a small amount of toluene. The total amount of toluene and water distilled off is
It was 3.1g. Next, the same treatment as in Example 2 was carried out to obtain 99 g of an oil layer. The concentration of γ-decalactone in the oil layer is 3.27% by weight, the concentration of 2-n-pentyl-2-cyclopentenone is 0.43% by weight, and the concentration of 2-n-butyl-2-cyclohexenone is 0.14% by weight.
It was hot. That is, the conversion rate of γ-decalactone was 19%, and the selectivity of 2-n-pentyl-2-cyclopentenone was 62%. Example 7 Using the same electrolytic cell and anolyte as in Example 5, 8.59 g (75.4 mmol) of heptanal as the catholyte,
Methyl acrylate 2.16g (25.1m mol), water 51.6
g, using a mixture of 8.11 g of tetra-n-butylammonium sulfate at a catholyte temperature of 28-29
Electrolysis was carried out at a temperature of 10.2 A/dm ² at a current density of 10.2 A/dm 2 . When the energization amount reached 104% of the theory, the energization was stopped and analyzed. The reaction rate of methyl acrylate was 86%, the reaction rate of heptanal was 12%, the selectivity of γ-decalactone was 37% based on methyl acrylate, and heptanal. Standard: 88%, current efficiency: 31%, selectivity for 1-heptanal: 10%, selectivity for methyl propionate
The selectivity for dimethyl adipate was 29%. Next, γ-decalactone was obtained in the same manner as in Example 5, and then a dehydration condensation reaction was performed. Stand,
Using the same reaction apparatus as in Example 2, 20 g of p-toluenesulfonic acid and 100 g of p-xylene were placed in a four-necked flask and heated until the p-xylene refluxed, and then the water that had refluxed together with the p-xylene was heated. was distilled off along with a small amount of p-xylene. Next, put 10 g of γ-decalactone into a four-necked flask.
A small amount of p-
The mixture was stirred for 2 hours while the xylene was distilled off. The total amount of p-xylene and water distilled off is 2.5
It was hot at g. After the reaction was completed, 50 g of water was added to the reaction solution to extract p-toluenesulfonic acid. The oil layer is
The concentration of γ-decalactone in the oil layer is 6.42% by weight, the concentration of 2-n-pentyl-2-cyclopentenone is 1.38% by weight, and the concentration of 2-n-butyl-
The concentration of 2-cyclohexenone was 0.46% by weight. In other words, the conversion rate of γ-decalactone is 32%.
The selectivity for 2-n-pentyl-2-cyclopentenone was 51%. Example 8 Using the same electrolytic cell and anolyte as in Example 5, the catholyte contained 8.61 g (7.75 mmol) of heptanal,
Methyl acrylate 2.18g (25.4m mol), water 54.2
g, monopotassium dihydrogen phosphate as a conductive substance
Using a mixture of 2.39 g and 1.01 g of tetra-n-butylammonium sulfate, the temperature of the catholyte was
Electrolysis was carried out at 28-30° C. and a current density of 10.2 A/dm ² . When the energization amount reached 106% of theory, the energization was stopped and an analysis was performed.The reaction rate of methyl acrylate was found to be
90%, heptanal reaction rate 18%, γ-decalactone selectivity 49% based on methyl acrylate, 82% based on heptanal, conductivity efficiency 42%, 1
- Heptanol selectivity 15%, methyl propionate selectivity 32%, dimethyl adipate selectivity 17
It was %. Next, γ-decalactone was obtained in the same manner as in Example 5, and then a dehydration condensation reaction was performed. That is, using the same reaction apparatus as in Example 2, 15 g of β-naphthalenesulfonic acid and 100 g of p-xylene were placed in a four-necked flask, heated until the p-xylene refluxed, and then refluxed together with the p-xylene. Water and a small amount of p-xylene were distilled off. Next, 5 g of γ-decalactone was placed in a four-necked flask and heated under reflux for 0.5 hour. During heating under reflux, the water produced was distilled off along with a small amount of p-xylene. The total amount of p-xylene and water distilled off was 5.2 g. Next, 20 g of water was added to the reaction solution to extract β-naphthalenesulfonic acid. The oil layer weighs 97g, and the concentration of γ-decalactone in the oil layer is 3.87% by weight, 2
-The concentration of n-pentyl-2-cyclopentenone is
The concentration of 2-n-butyl-2-cyclohexenone was 0.22% by weight. That is, γ
-The conversion rate of decalactone is 25%, 2-n-
Selectivity for pentyl-2-cyclopentenone is 56%
It was hot. Example 9 Tetra-n-butylammonium sulfate
Electrolysis was carried out in the same manner as in Example 5, except that 0.94 g of tetra-n-propylammonium bromide was used instead of 1.00 g. The reaction rate of methyl acrylate is 96%, the reaction rate of heptanal is 12%, the selectivity of γ-decalactone is 24% based on methyl acrylate, 63% based on heptanal, the current efficiency is 22%, and 1- Heptanol selectivity is 30%, methyl propionate selectivity is 25
%, and the selectivity for dimethyl adipate was 40%. Next, γ-decalactone was obtained in the same manner as in Example 5, and then a dehydration condensation reaction was performed. That is,
Using the same apparatus as in Example 2, 2 g of trifluoromethanesulfonic acid, 100 g of p-xylene, and 2 g of γ-decalactone were placed in a four-necked flask and heated under reflux for 0.5 hour. During heating under reflux, a total of 1.9 g of water produced was distilled off along with a small amount of p-xylene.
Next, 20 g of water was added to the reaction solution to extract and remove trifluoromethanesulfonic acid. The oil layer is 96g,
The concentration of γ-decalactone in the oil layer is 1.54% by weight,
The concentration of 2-n-pentyl-2-cyclopentenone was 0.31% by weight, and the concentration of 2-n-butyl-2-cyclohexenone was 0.10% by weight. That is,
The conversion rate of γ-decalactone was 26%, and 2-n
-Selectivity of pentyl-2-cyclopentenone is 64
It was %. Example 10 Tetra-n-butylammonium sulfate
Electrolysis was carried out in the same manner as in Example 5, except that 2.73 g of benzyl tri-n-butylammonium chloride was used instead of 1.00 g. The reaction rate of methyl acrylate is 94%, the reaction rate of heptanal is 18%, the selectivity of γ-decalactone is 50% based on methyl acrylate, 90% based on heptanal, the current efficiency is 45%, and 1- Heptanol selectivity 4%, methyl propionate selectivity 7
%, and the selectivity for dimethyl adipate was 25%. Next, γ-decalactone was obtained in the same manner as in Example 5, and then a dehydration condensation reaction was performed. That is,
Using the same apparatus as in Example 2, 2.5 g of p-toluenesulfonic acid, 1.0 g of trifluoromethanesulfonic acid, and 100 g of toluene were placed in a four-necked flask and heated, and the water that had azeotroped with the toluene was distilled off. .
Next, 2.5 g of γ-decalactone was placed in a four-necked flask and heated under reflux for 4 hours. Water produced during reflux heating was distilled out of the system along with a small amount of toluene.
The total amount of water and toluene distilled off was 18 g. Next, 10 g of water was added to the reaction solution to extract the sulfonic acid, yielding 84 g of an oil layer. The concentration of γ-decalactone in the oil layer is 2.11% by weight, 2-n-pentyl-2
-The concentration of cyclopentenone is 0.50% by weight, 2-n
The concentration of -butyl-2-cyclohexenone was 0.17% by weight. That is, the conversion rate of γ-decalactone was 29%, and the selectivity of 2-n-pentyl-2-cyclopentenone was 65%. Example 11 Tetra-n-butylammonium sulfate
Electrolysis was carried out in the same manner as in Example 5, except that 1.19 g of tetra-n-butylphosphonium bromide was used instead of 1.00 g. The reaction rate of methyl acrylate is 94%, the reaction rate of heptanal is 23%, and the selectivity of γ-decalactone is 65% based on methyl acrylate and 88% based on heptanal.
%, the current efficiency was 58%, the selectivity for 1-heptanol was 6%, the selectivity for methyl propionate was 5%, and the selectivity for dimethyl adipate was 16%. Next, γ-decalactone was obtained in the same manner as in Example 5, and then a dehydration condensation reaction was performed. That is,
Using the same reaction apparatus as in Example 2, 15 g of p-toluenesulfonic acid and 100 g of toluene were placed in a four-necked flask.
g was added and heated, water that had azeotroped with toluene was distilled off, and then toluene was also distilled off. Next, 120 g of diethyl diphenyl and 4 g of γ-decalactone
Place each in a four-necked flask and adjust the reaction temperature.
Stir at 150℃ for 2 hours. During the reaction, a trace amount of water adhered to the condenser. Next, the same treatment as in Example 2 was carried out to obtain 121 g of an oil layer. The concentration of γ-decalactone in the oil layer is 2.34% by weight, the concentration of 2-n-pentyl-2-cyclopentenone is 0.43% by weight, 2
-The concentration of n-butyl-2-cyclohexenone is
It was 0.13% by weight. That is, the conversion rate of γ-decalactone is 30%, and the conversion rate of 2-n-pentyl-2
-The selectivity of cyclopentenone was 49%. Example 12 Using the same electrolytic cell and anolyte as in Example 5, butanal 5.37g (74.6m) was used as the catholyte.
mol), methyl acrylate 2.17g (25.2m mol),
A mixture of 54.9 g of water and 6.23 g (17.5 mmol) of tetraethylammonium sulfate was used. Keeping the temperature of the catholyte at 27-28℃ and stirring thoroughly with a magnetic stirrer, increase the current density to 10.2A/
Electrolysis was carried out at ^dm2 . When the theoretical current flow reached 106%, the electrolysis was terminated and the catholyte was analyzed by gas chromatography.The reaction rate of methyl acrylate was 94%, the reaction rate of butanal was 30%, and the selectivity of γ-heptalactone was 77 based on acrylic ester
%, based on butanal, the current efficiency was 68%, the selectivity for 1-butanal was 13%, the selectivity for methyl propionate was 5%, and the selectivity for dimethyl adipate was 1%. The above electrolytic reaction was repeated, the resulting electrolytic solution was collected and separated into two layers, and γ-heptalactone was obtained from the oil layer by distillation. Next, a dehydration condensation reaction was carried out in the same manner as in Example 2. The results were similar to Example 2. Example 13 Electrolysis was carried out in the same manner as in Example 12 except that 9.88 g of tetra-n-butylammonium sulfate was used instead of tetraethylammonium sulfate, and the reaction rate of methyl acrylate was 100.
%, butanal reaction rate is 25%, γ-heptalactone selectivity is 66% based on methyl acrylate, 90% based on butanal, current efficiency is 63%, and 1-
The selectivity for butanal was 1%, the selectivity for methyl propionate was 1% or less, and the selectivity for dimethyl adipate was 8%. Next, γ-heptalactone was obtained in the same manner as in Example 12, and then a dehydration condensation reaction was performed. The results were similar to Example 12. Example 14 Using the same electrolytic cell and anolyte as in Example 5, butanal 5.24g (74.8m mol), methyl acrylate 2.13g (24.8m mol), water 54.6g as catholyte,
2.36g of monopotassium dihydrogen phosphate as a conductive substance
and 0.193 g of tetra-n-butylammonium sulfate at a catholyte temperature of 28 ~
Electrolysis was performed at 33° C. and a current density of 10.2 A/dm ² . When the energization amount reached 107% of the theoretical, we stopped the energization and analyzed it, and found that the reaction rate of methyl acrylate was 89%, the reaction rate of butanal was 37%, and the selectivity of γ-heptalactone was 70% based on methyl acrylate. The current efficiency was 58% based on butanal, the selectivity for 1-butanal was 16%, the selectivity for methyl propionate was 1% or less, and the selectivity for dimethyl adipate was 3%. Next, γ-heptalactone was obtained in the same manner as in Example 12, and then a dehydration condensation reaction was performed. The results were similar to Example 12. Comparative Example 1 Using the same reaction apparatus as in Example 2, 5 g of γ-decalactone, 20 g of polyphosphoric acid, and 100 g of p-xylene were placed in a four-necked flask and heated under reflux for 2 hours. Next, the reaction solution was cooled to 60°C, 100g of water was added, and the mixture was further stirred for 1 hour. The conversion rate of γ-decalactone was 100%, and 2-n-pentyl-2-
The selectivity for cyclopentenone was 28%. Comparative Example 2 Using the same reaction apparatus as in Example 2, 5 g of γ-decalactone and 15 g of dichloroacetic acid were placed in a four-necked flask.
and 100 g of p-xylene were added, and the mixture was heated under reflux for 5 hours. During heating under reflux, a total of 10 g of xylene was distilled off. The reaction hardly progressed, almost all of the γ-decalactone remained, and 2-n-pentyl-2-cyclopentenone was not produced. Comparative Example 3 Dihydrogen phosphate 1, an inorganic substance, as a conductive substance
Using 2.35g of potassium, this and 5.23g of butanal
(72.6m mol), methyl acrylate 2.15g (25.0m
Electrolysis was carried out in the same manner as in Example 1, except that a mixture of 53.7 g of water (mol) and 53.7 g of water was used as the catholyte. Electrolysis was terminated when the theoretical energization amount reached 102%, and analysis revealed that the reaction rate of methyl acrylate was 85%, the reaction rate of butanal was 38%, and the selectivity of γ-heptalactone was 48% based on methyl acrylate. , 37% based on butanal, current efficiency 40%, selectivity of 1-butanal
The selectivity for methyl propionate was 9%, and the selectivity for dimethyl adipate was 1%. Comparative example 4 Dihydrogen phosphate 1, an inorganic substance, as a conductive substance
Using 2.37g of potassium, this and 8.61g of heptanal
g (75.5m mol), methyl acrylate 2.16g
Electrolysis was carried out in the same manner as in Example 8 except that a mixture of (25.1 mmol) and 52.8 g of water was used as the catholyte.
When the energization amount reached 105% of the theoretical amount, the energization was stopped and analyzed, and the reaction rate of methyl acrylate was 83%.
Heptanal reaction rate 5%, 4-n-hexyl-
The selectivity of 4-butanolide is 5% based on methyl acrylate, 26% based on heptanal, and the current efficiency is 4%.
The selectivity for 1-heptanal was 74%, the selectivity for methyl propionate was 82%, and the selectivity for dimethyl adipate was 10%.

Claims (1)

[Claims] 1. Acrylic acid ester and general formula R ¹ CH ₂ COR ²
A mixture of carbonyl compounds represented by (R ¹ , R ² are hydrogen or alkyl groups) is electrolytically reduced on a cathode made of lead or an alloy containing lead as a main component to obtain the general formula [Formula] (R ¹ , R ² γ-lactones represented by hydrogen or alkyl groups are produced, and the resulting water is reacted with the γ-lactones in an inert solvent that does not dissolve in water in the presence of a sulfonic acid catalyst. A method for producing 2-cyclopentenones represented by the general formula [Formula], which comprises heating while removing the compounds. 2 The carbonyl compound is a ketone, the catholyte is made into a homogeneous solution state, sulfuric acid is used as the supporting electrolyte, the current density of the cathode is set in the range of 1 to 5 A/dm ² , and the concentration of acrylic acid ester in the catholyte is set to 1. ~
2. The method according to claim 1, wherein the electrolytic reduction is carried out by adding the acrylic acid ester intermittently or continuously to the catholyte so as to maintain the content within the range of 5% by weight. 3. The method according to claim 2, wherein the ketone is an aliphatic ketone having 3 to 10 carbon atoms. 4. The method according to claim 2, wherein the sulfuric acid concentration in the catholyte is 0.1 to 5% by weight. 5. The method according to claim ² , wherein the current density is 1 to 3 A/dm2. 6 Acrylic acid ester concentration in catholyte is 1 to 3
3. A method according to claim 2, wherein the amount is % by weight. 7. The method according to claim 2, wherein the electrolytic reduction is carried out at a temperature of 40 to 70°C. 8. The carbonyl compound is an aldehyde, and the presence of an electrically conductive substance that causes the catholyte to be in an aqueous emulsion state and has at least one kind of phase transfer catalytic ability selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts. The method according to claim 1, characterized in that electrolytic reduction is performed below. 9. The method according to claim 8, wherein the acrylic ester is a lower alkyl ester of acrylic acid. 10. The method according to claim 9, wherein the lower alkyl ester of acrylic acid is methyl acrylate. 11. The method according to claim 8, wherein the volume ratio of the non-aqueous phase in the emulsion to the total emulsion is 0.05 to 0.5. 12. The method according to claim 8, wherein electrolytic reduction is carried out by diaphragm electrolysis. 13. The method according to claim 8, wherein the molar ratio of aldehyde to acrylic ester is from 1 to 5. 14. The method according to claim 8, which is carried out in the coexistence of an electrically conductive substance whose cations are inorganic cations that do not have phase transfer catalytic ability. 15 Claim No. 1, wherein the conductive substance whose cation is an inorganic cation without phase transfer catalytic ability is at least one inorganic compound selected from the group consisting of sulfuric acid, phosphoric acid, and alkali metal salts thereof. The method described in item 14. 16 The aldehyde is an aliphatic aldehyde having 1 to 4 carbon atoms, and the quaternary ammonium salt has the general formula (In the formula, R ¹ , R ² , R ³ and R ⁴ are each the same or different alkyl group, the total number of carbon atoms of these groups is 4 to 20, and X is an acid group,
n is an integer and corresponds to the ionic valence of X. ) The method according to claim 8, which is a compound represented by: 17. The method according to claim 16, wherein R ¹ , R ² , R ³ and R ⁴ in the general formula are all alkyl groups, and the total number of carbon atoms in these alkyl groups is 4 to 16. 18 Claim 1, wherein the alkyl group is at least one kind of alkyl group selected from the group consisting of methyl group, ethyl group, propyl group, and butyl group.
The method described in Section 7. 19 The aldehyde is an aliphatic aldehyde having 5 to 13 carbon atoms, an aromatic aldehyde, or an araliphatic aldehyde, and the quaternary ammonium salt has the general formula (R ¹ , R ² , R ³ and R ⁴ in the formula are each the same or different alkyl group or aralkyl group, and the total number of carbon atoms in these groups is 12 to 20,
X is an acid group, and n is an integer corresponding to the ionic valence of X. ) The method according to claim 8, which is a compound represented by: 20 The method according to claim 19, wherein R ¹ , R ² , R ³ and R ⁴ in the general formula are all alkyl groups, and at least three of them are alkyl groups having 3 or more carbon atoms. . 21. The method according to claim 20, wherein the alkyl group is at least one alkyl group selected from the group consisting of propyl and butyl groups. 22. The method according to claim 21, wherein all the alkyl groups are butyl groups. 23 The aldehyde is an aliphatic aldehyde having 5 to 13 carbon atoms, an aromatic aldehyde, or an araliphatic aldehyde, and the quaternary ammonium salt has the general formula (R ¹ , R ² , R ³ and R ⁴ in the formula are each the same or different alkyl group or aralkyl group, X is an acid group, and n is an integer with a value corresponding to the ionic valence of X. ), the total number of carbon atoms of R ¹ , R ² , R ³ and R ⁴ is 4 to 11, and the total number of carbon atoms of R ¹ , R ² , R ³ and R ⁴ is 12
Claim 8 which is a mixture with ~30
The method described in section. 24 The aldehyde is an aliphatic aldehyde, an aromatic aldehyde, or an araliphatic aldehyde having 5 to 13 carbon atoms, and has the general formula (R ¹ , R ² , R ³ and R ⁴ in the formula are each the same or different alkyl group or aralkyl group, and the total number of carbon atoms of these groups is 4 to 11,
X is an acid group, and n is an integer corresponding to the ionic valence of X. 9. The method according to claim 8, wherein a quaternary ammonium salt represented by the following formula is used in combination with a quaternary phosphonium salt. 25 R ¹ , R ² , R ³ and R ⁴ in the general formula have 3 carbon atoms
The method according to claim 23 or 24, wherein the alkyl group is the following alkyl group. 26. The method according to claim 25, wherein all the alkyl groups are ethyl groups. 27 The aldehyde is an aliphatic aldehyde, aromatic aldehyde or araliphatic aldehyde having 5 to 13 carbon atoms, (R ¹ , R ² , R ³ and R ⁴ in the formula are each the same or different alkyl group or aralkyl group, and the total number of carbon atoms in these groups is 12 to 30,
X is an acid group, and n is an integer corresponding to the ionic valence of X. 9. The method according to claim 8, wherein a quaternary ammonium salt or a quaternary phosphonium salt represented by the following formula is used in combination with a conductive substance whose cation is an inorganic cation having no phase transfer catalytic ability. 28 Based on the usage amount of the quaternary ammonium salt in which the total number of carbon atoms of R ¹ , R ² , R ³ and R ⁴ in the general formula is 12 to 30, and the acrylic ester is based on the smaller amount of aldehyde used, 28. The method according to claim 23 or 27, wherein the amount is in the range of 0.1 to 50 mol%. 29. The method according to claim 24 or 27, wherein the amount of the quaternary phosphonium salt used is in the range of 0.1 to 50 mol% based on the lesser of the acrylic ester or the aldehyde. 30 Claims 16, 19, and 19, wherein X in the general formula is a sulfate ion, hydrogen sulfate ion, sulfonate ion, phosphate ion, hydrogen phosphate ion, dihydrogen phosphate ion, or halogen ion The method according to item 23, item 24 or item 27. 31. The method according to claim 1, wherein X in the general formula is a sulfate ion, hydrogen sulfate ion, sulfonate ion, phosphate ion, hydrogen phosphate ion or dihydrogen phosphate ion. 32. The method according to claim 1, wherein R ¹ of the γ-lactone is an alkyl group. 33. The method according to claim 1, wherein the inert solvent is an aromatic hydrocarbon. 34. The method according to claim 1, wherein the inert solvent is used in an amount of 5 parts by weight or more and 100 parts by weight or less based on 1 part by weight of γ-lactone. 35. The method according to claim 1, wherein the sulfonic acid catalyst is soluble in the solvent at the reaction temperature. 36 Sulfonic acid catalyst against γ-lactone
The method according to claim 1, which is used in an amount of 0.2 times mole or more and 5 times mole or less. 37. The method according to claim 1, wherein the heating is performed at a temperature range of 90°C or higher and 230°C or lower. 38 Claim 28, in which R ¹ of the γ-lactone is an alkyl group and R ² is hydrogen
The method described in section.