JPS6241319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses an electrolytic cell having a structure in which an anode chamber is divided into at least two or more chambers by a protective diaphragm when performing an organic compound electrolytic reaction using a cation exchange membrane.
The present invention relates to an electrolytic method characterized in that electrolytic reduction and electrolytic oxidation are performed simultaneously or only electrolytic reduction is performed.

Specifically, the anode and cathode are separated by a cation exchange membrane having a cationic functional group on at least one surface, and the anode and cathode are separated by a cation exchange membrane having a cationic functional group on at least one surface. has a specific electrical resistance of 2000Ω・
Using an electrolytic cell in which an anode chamber, an intermediate chamber, and a cathode chamber are formed by dividing them by a diaphragm of less than cm, an electrolyte solution of an organic compound having a reducible functional group is supplied to the cathode chamber, and an anode An electrolyte solution of an organic compound having an oxidizable functional group or an electrolyte solution not containing the organic compound is supplied to the chamber to conduct electrolysis. This is an electrolytic method that only performs reduction.

In an organic compound electrolytic synthesis reaction using a cation exchange membrane as a diaphragm, water decomposition usually occurs at the anode, producing oxygen and hydrogen ions, and if there is an organic compound with a functional group that can be oxidized in the anode chamber solution, an oxidation reaction will occur. If no organic compounds are present, mainly oxygen gas or halogen gas will be generated. Further, the generated hydrogen ions are supplied to the cathode chamber through the cation exchange membrane. On the other hand, at the cathode, if there is an organic compound having a functional group that can be reduced to the cathode chamber solution, a reduction reaction will occur, and if no organic compound is present, hydrogen gas will be generated.

Conventional electrolytic reactions of organic compounds using cation exchange membranes as diaphragms are often limited to methods that utilize either the cathode or the anode to perform either reduction or oxidation reactions. As a result, the electricity consumption rate was high, and industrialization was often postponed.

When electrolytic synthesis reactions occur simultaneously at both the positive and negative electrodes, if the molecular weights of both organic compounds are small, they may be mixed by diffusion through a cation exchange membrane, or if cationic organic compounds are present in the anode chamber solution. When hydrogen ions pass through the cation exchange membrane, a considerable amount passes through the cation exchange membrane, which often has the disadvantage of reducing the purity of the reduced organic compounds in the cathode compartment and further loss of oxidation products at the anode. This was also a reason why it was difficult to adopt an electrolytic method in which the reduction and oxidation reactions of organic compounds were carried out simultaneously.

As a result of various studies, the present inventors proposed a method previously disclosed in Japanese Patent Application Laid-Open No. 50471/1983 as a method for solving these drawbacks. That is, in this method, an electrolyte solution of an organic compound having a functional group to be reduced is placed in a cathode chamber, and an electrolyte solution of an organic compound having a functional group to be oxidized is placed in an anode chamber, and electrolytic reduction and electrolytic oxidation are performed simultaneously. This is an electrolysis method characterized by using a cation exchange membrane in which cationic functional groups are uniformly present on at least one surface within a range that does not substantially increase the electrical resistance of the membrane. . According to this method, when organic electrolytic reactions are simultaneously carried out at both electrodes, mixing of organic compounds with each other can be extremely reduced, and organic electrolysis can be carried out efficiently.

However, even with the method disclosed in JP-A No. 55-50471, when operating for a long period of time, there is a phenomenon that the mixing of organic substances at both electrodes is extremely small, and the effect of efficient organic electrolysis gradually fades. It will be done. This is presumed to be due to the gradual oxidation of the portion in which a cationic functional group is present on at least one surface of the cation exchange membrane within a range that does not substantially increase the electrical resistance of the membrane.

Therefore, as a result of further intensive research, the present inventors found that by providing a protective diaphragm between the anode and the cation exchange membrane, it is possible to prevent organic matter from entering the electrode chamber even after long-term operation. Surprisingly, the present invention was completed based on the knowledge that organic substances can be efficiently electrolyzed with a very small amount. That is, the anode and the cathode are separated by the cation exchange membrane, and the anode and the cation exchange membrane are separated by a diaphragm having a specific electrical resistance of 2000 Ω-cm or less, thereby forming an anode chamber,
Using an electrolytic cell in which an intermediate chamber and a cathode chamber are formed, an electrolyte solution of an organic compound having a reducible functional group is supplied to the cathode chamber, and an electrolyte solution of an organic compound having an oxidizable functional group or an electrolyte solution of an organic compound having an oxidizable functional group is supplied to the anode chamber. This is an electrolytic method in which electrolytic reduction and electrolytic oxidation of an organic compound are simultaneously performed or only electrolytic reduction is performed, characterized in that electrolysis is performed by supplying an electrolyte solution that does not contain the organic compound.

Conventionally, in alkali metal salt electrolysis such as salt electrolysis, it has been used as a means to prevent oxidative deterioration of cation exchange membranes due to halogen gases such as chlorine gas generated at the anode.
It is known to electrolyze an aqueous alkali metal salt solution by disposing a protective diaphragm such as asbestos or a porous fluorine-containing diaphragm between an anode and a cation exchange membrane. At this time, in order to prevent oxidizing substances generated at the anode from entering the intermediate chamber formed by the cation exchange membrane and the porous diaphragm, various methods have been proposed, such as controlling the flow rate of the anolyte and intermediate chamber liquid. ing. However, electrolysis of an aqueous alkali metal salt solution essentially involves only inorganic salt compounds that generate oxidizing compounds; different. Furthermore, in the case of electrolysis of alkali metal salts, even if an oxidation-resistant protective membrane such as asbestos or a porous fluorine-containing membrane is provided, deterioration of the performance of the cation exchange membrane over time cannot be avoided. On the other hand, in the present invention, not only is it effective to use an inorganic material such as asbestos or a fluorine-containing protective film such as Teflon, but it is also extremely effective to use a protective film made of parchment paper or hydrocarbon. Therefore, oxidative deterioration of the ion exchange membrane can be completely avoided. Furthermore, the use of the protective diaphragm of the present invention has a more than expected effect in that the contamination of organic substances, especially in the electrode chamber, can be extremely reduced. The reason why the type of protective diaphragm and the effect of the protective diaphragm are so different compared to the case of alkali metal salt electrolysis is probably because the effect of the protective diaphragm is essentially different in the case of the present invention.

Note that the present invention is effective not only when electrolytic reduction and electrolytic oxidation are performed simultaneously, but also when only electrolytic reduction is performed.

As described above, as a result of various studies on the ``Electrolytic Method'' disclosed in Japanese Patent Application Laid-open No. 55-50471, we have completed the even more excellent invention.

The protective membrane used in the present invention is usually a commercially available parchment paper, an acetyl cellulose membrane, a semipermeable membrane made of cellophane, or a porous membrane made of polyvinyl fluoride, ABS, polystyrene, polyvinyl chloride, polyethylene, polypropylene, etc. Neutral membranes, porous diaphragms made by coating latex such as polyvinyl chloride on various base cloths and drying them, or polymerizable monomers, and if necessary plastic fine powder and non-polymerizable substances. Diaphragms and the like that are made into porous bodies by coating and polymerizing reinforcing materials and then removing non-polymerizable substances are widely used. Also, commercially available woven fabrics and nonwoven fabrics such as cloth and net can also be suitably used as the porous diaphragm.

The first property required for the protective diaphragm of the present invention is high electrical conductivity in an organic compound electrolyte or electrolyte solution, and if it has a specific electrical resistance of 2000 Ω-cm or less, water permeability, It is effective regardless of its name, such as semi-permeable, non-permeable, non-porous, or porous. More preferably, it has excellent oxidation resistance, chemical, thermal, and mechanical properties, and is economical.

In general, the porosity of the protective diaphragm when projected in the current direction should generally be 20% or less, preferably 5% or less, and should be selected according to the practical electrolytic conditions in balance with the above-mentioned required properties. do it. For example, electrical conductivity varies greatly depending on the diameter and number of pores communicating in the film, affinity with the electrolyte, etc., but the mechanical properties including oxidation resistance must be maintained to the extent that long-term durability can be maintained from an economical point of view. By reducing the intensity of
Instead, the film may be selected to increase the diameter and number of holes through which the film communicates, and to increase electrical conductivity.

As the protective membrane used in the present invention, semipermeable membranes such as non-porous hydrophilic polyvinyl alcohol films or hydrolyzed films of ethylene/vinyl acetate copolymer are also extremely effective.

The organic compound used in the present invention may be either ionic or nonionic. In addition, the organic compound having a functional group to be reduced used in the cathode chamber and the organic compound having a functional group to be oxidized to be used in the anode chamber are not particularly limited. The functional group and the organic compound having the functional group can be used without any restriction. To give some specific examples, examples of organic compounds having a functional group that can be reduced include nitrobenzene,
Aromatic nitro compounds such as nitroaniline, dinitrophenol, nitrobenzoic acid; carbonyl compounds such as acetone, acetophenone, allylaldehyde, glyoxal; organic acids such as benzoic acid, oxalic acid, propionic acid; phthalic acid, maleic acid, acrylonitrile, etc. Unsaturated compounds; cyano compounds such as cyanopyrimidine, butyronitrile, malonitrile; heterocyclic compounds such as pyridine and quinoline; halogen compounds such as chloraminopyrimidine; saccharides such as glucose and xyrose. When the organic compound is water-insoluble, a cosolvate such as methanol or tetrahydrofuran may be used in combination, or an alkyl quaternary ammonium salt or an alkyl sulfuric acid quaternary ammonium salt may be used as a supporting salt and an emulsifier.

Organic compounds with oxidizable functional groups include carbonyl compounds such as butyric acid ethyl ester, stearic acid, and glyoxal; aromatic compounds such as benzene, naphthalene, and anthracene; pyridine,
Heterocyclic compounds such as quinoline; alcohols such as ethanol, propanol, and γ-aminopropanol; if they are insoluble in water, use alkyl quaternary ammonium salts and alkyl sulfate quaternary ammonium salts as supporting salts and emulsifiers. Can be done. Further, when the electrical conductivity of the organic compound aqueous solution is poor, an acid or alkali can be added as appropriate. The above-mentioned organic compounds to be oxidized and reduced are merely examples, and are not limited to the gist of the present invention.

The cation exchange membrane used in the present invention may be a homogeneous membrane, a heterogeneous membrane, a condensation type membrane or a polymerization type membrane, as long as it has a cationic functional group on its surface.
Hydrocarbon membranes, fluorine-containing membranes, perfluorocarbon membranes, and the presence or absence of reinforcing materials, types of ion exchange membranes, etc. can be used without particular limitations. In particular, as described above, the present invention has a particularly remarkable effect when both the redox and oxidation reactions described in JP-A-55-50471 are carried out. That is, one of the features of the present invention is that, in order to obtain such an effect, cationic functional groups are added to the surface layer of the cation exchange membrane, particularly on the side that comes into contact with the anolyte, within a range that does not substantially increase the electrical resistance of the membrane. The purpose is to use a uniform film. Conventionally known films of this type include Japanese Patent Publications No. 46-23607 and No. 47-3801.
No. 47-3802, No. 46-42082, No. 50-4638
Items listed in the number may be used without any restriction.

In addition, the present applicant et al. proposed a cation exchange membrane in Japanese Patent Application No. 53-66661, that is, one side of a polymer membrane in which acid halide groups exist in a statistically uniform distribution. is brought into contact with an alkaline solution to substantially hydrolyze the acid halide groups, and the membrane is then reacted with a primary or/and secondary amino compound solution, and then further immersed in an alkaline solution. For example, a cation exchange membrane that has an acid amide group on one side only and is produced by hydrolyzing the acid halide groups remaining in the membrane. It can be used preferably. In addition, one or more low-molecular or high-molecular compounds having a cationic functional group with a molecular weight of 100 or more are adsorbed onto the surface of the membrane, ion exchange, covalent chemical bonds, coordinate bonds, etc. Regarding the electrical resistance of a membrane that is uniformly present on the surface of the exchange membrane and in which the cationic functional group is not present,
It is also effective to use a film under conditions where the electrical resistance of the existing film does not increase by more than 10 times. The presence of a large amount of cationic functional groups causes a rise in the electrical resistance of the membrane and increases the power consumption of the product, which is not suitable for industrial use. Generally, the abundance of such cationic compounds is
It is effective if it exists in an amount of 0.001 mg/dm ² or more.

Also, JP-A No. 49-89692, No. 49-91086, No. 49
Cation exchange membranes into which cationic functional groups have been introduced, such as those disclosed in No. 91088 and No. 49-91087, are also effective.

As described above, a particularly preferable cation exchange membrane is one in which cationic functional groups are uniformly present on at least one surface by covalent bonding, ionic bonding, or adsorption within a range that does not substantially increase the electrical resistance of the membrane. When using a cation-exchange membrane with polyethyleneimine or a cation-exchange membrane in which polyethyleneimine is covalently fixed via a sulfone group, cationic functional groups are present at least on the surface of the membrane in contact with the anolyte. It only needs to exist, there are no other restrictions.

In addition to organic compounds that are anodized in the anode chamber, organic and inorganic compounds with a molecular weight of 100 or more that do not substantially pass through the cation exchange membrane and that have a functional group that becomes positively charged in the operating atmosphere can be used for electrolysis. Electrolysis may be carried out with or without adding a substance that does not participate in oxidation. in this case,
Naturally, the substance is electrophoretically pressed against the anode surface of the cation exchange membrane, forming a positively charged layer on the membrane surface.

Next, the electrolytic cell used in the present invention has an anode chamber and a cathode chamber, between which one or more special cation exchange membranes having the above-mentioned cationic charges on the surface layer are disposed, and further between the anode and the cathode chamber. One or more of the above-mentioned protective diaphragms are present between the cation exchange membranes. In general, both protective diaphragms and cation exchange membranes have large areas when used in industrial equipment, and unless the water pressure is equalized on both sides of the membrane, the membrane will become deformed and eventually lead to pinholes and damage. .
Therefore, it is necessary to bring the cathode and the cation exchange membrane into close contact with each other or to support them with a spacer or the like. Preferably, a spacer having a shielding rate of 20% or less is disposed on the cathode, and a cation exchange membrane is disposed thereon. In this case, the shielding rate is defined as the rate of increase in the electrical resistance of the system by measuring the electrical resistance of the solution in the same electrolytic cell with and without a spacer. When this shielding rate exceeds 20%, the electrical resistance of the system increases, which is not only industrially disadvantageous, but also affects the reduction reaction rate on the electrode, which is undesirable.

Similarly, it is desirable to arrange a protective diaphragm on the anode side via a spacer with a shielding rate of 20% or more. However, in the case of an anode, the protective diaphragm may be supported in direct contact with the anode without necessarily using a spacer. In particular, when only the reduction reaction is carried out at the cathode, it is not necessary to use a spacer. In addition, the gap between the anion exchange membrane and the protective diaphragm is generally 0.5 mm to 50 mm.
It is preferable to keep it at mm. When a porous protective diaphragm is used, since liquid flows between the protective diaphragm and the cation exchange membrane, the liquid used in the intermediate chamber and the anode chamber may be the same. Also,
When using a non-water permeable protective diaphragm, separate anolyte and intermediate chamber liquids may be used. Furthermore, even if the protective membrane is porous, in the case of a membrane with extremely low water permeability, both the anolyte and the intermediate chamber liquid can be supplied separately. In such a case, it is preferable to maintain the liquid pressure in the intermediate chamber higher than the liquid pressure in the anode chamber for electrolysis.

In this case, the flow rate of the solution in each chamber varies depending on the current density and reaction conditions, but in the intermediate chamber, it is necessary to have both speeds that can be operated at a current density below the limit current density of the cation exchange membrane, or to use stirring. If the flow rate of the anolyte or catholyte is too slow or the stirring is insufficient, side reactions will occur in addition to the main reaction, resulting in a decrease in the yield of the oxidation reaction and reduction reaction. It is desirable that the flow rate is such that a yield of 60% or more can be maintained. In addition, the supply of liquid, temperature, etc. are not particularly different from those conventionally known, and energy consumption is as low as possible.
In addition, conditions with the highest reaction efficiency are selected.

As described above, the present invention shows an embodiment in which an anode chamber, one or more protective diaphragms, one or more cation exchange membranes, and a cathode chamber are used, but in manufacturing the electrolytic cell,
In view of maintenance and economical constraints, the most preferred embodiment uses an electrolytic cell with a three- or four-chamber structure consisting of an anode chamber, one protective diaphragm, one or two cation exchange membranes, and a cathode chamber. This is the case. In the case of electrolyzing a large amount of organic compounds, the above-mentioned at least three- or four-chamber unit may be used as one unit, and a large number of these units may be laminated. In this case, the method of supplying power to the electrolytic cell may be either a monopolar type or a bipolar type. Also, the liquid supply method may be an individual liquid supply method for each chamber or a branched liquid supply method.

In addition, the cathode materials used for the electrodes include iron, nickel,
Palladium, lead, lead alloy, silver, platinum, gold, titanium, etc.; as anode materials, lead peroxide, lead, lead alloy, platinum plating, niobium, titanium, tantalum, carbon, titanium oxide, ruthenium oxide, etc. on titanium; Conventionally known electrode materials, such as those containing noble metal oxides, can be used as flat plates, net-like bodies, or rod-like bodies without any limitations.

According to the electrolysis method of the present invention, the cation exchange membrane has good durability even after repeated long-term continuous operation or batch operation, and the mixing of organic substances in the electrode chamber is extremely small, resulting in efficient electrolytic reduction and reduction of organic substances. Electrolytic oxidation can be carried out simultaneously or only electrolytic reduction can be carried out. Therefore,
The electrolysis method of the present invention is generally carried out below the water decomposition voltage at the anode, but it can also be effectively employed under highly oxidizing operating conditions. For example, it is effective when performing an oxidation reaction of an organic compound that is difficult to oxidize, when performing an oxidation reaction while generating oxygen gas, or when other oxidizing substances are produced.

The method for manufacturing the cation exchange membrane used in the examples is described below, and the method for manufacturing the cation exchange membrane in which functional groups that can become cations are present on the surface within a range that does not substantially increase the electrical resistance of the membrane is described. There are various methods as exemplified above, and the film shown in this example is
Needless to say, this is just one example.

(1) 0.1 part of polyvinyl chloride powder, 1.8 parts of styrene,
After uniformly mixing 0.2 parts of divinylbenzene, 0.3 parts of dioctyl phthalate, and 0.1 parts of benzoyl peroxide, the mixture was applied to a polyvinyl chloride cloth, covered with cellophane film on both sides, and polymerized at 110°C for 4 hours. - React with a mixed solution of chlorsulfonic acid (1:1) at 40℃ for 30 minutes, and apply the reacted membrane to an 80% aqueous sulfuric acid solution and 30%
Each sample was immersed in an aqueous sulfuric acid solution for 10 minutes, and after washing with pure water, one side was reacted with a 10% aqueous solution of polyethyleneimine having a molecular weight of 3,000 to 7,000 at room temperature for 24 hours to form a sulfonic acid amide on one side. Next, the membrane was immersed in a 10% caustic soda aqueous solution for 30 minutes at room temperature to hydrolyze the sulfonyl chloride groups, treated with a 10% sulfuric acid aqueous solution for 30 minutes, thoroughly rinsed with water, and used as a membrane for electrolytic redox. .
This film was referred to as A film in the examples.

(2) The membrane before the polyethyleneimine treatment was treated with a 10% aqueous solution of caustic soda to hydrolyze the sulfonyl chloride groups, then washed with pure water, treated with a 10% aqueous sulfuric acid solution, and thoroughly washed with pure water. This film was designated as B film.

(3) Film B is made of poly(N-methyl-N-
One side was treated with a 0.1% aqueous solution of (hydroxy)2vinylpyridine for 8 hours and thoroughly washed with water. This film is C
It was described as a membrane.

(4) Film B was treated on one side with a 0.1% aqueous solution of poly(N·N·N-trimethyl)vinylbenzylammonium hydroxide having a degree of polymerization of 340 for 8 hours, and then thoroughly washed with water. This film was designated as D film.

The membrane resistances of the A, B, C, and D membranes were measured using 1000 alternating current cycles in a 0.5N-NaCl aqueous solution and were as follows.

A film: 2.7Ωcm ² B film: 2.5Ωcm ² C film: 3.0Ωcm ² D film: 3.4Ωcm ² Example 1 Using a lead flat plate as the cathode and a lead plate coated with lead peroxide as the anode. , the cathode chamber and the anode chamber are divided by installing the sulfonic acid type cation exchange membrane A with the surface treatment layer facing the anode side with a distance between electrodes of 4 mm, and the porosity is 3% when projected in the direction of current flow. A commercially available polyvinyl chloride cloth (thickness: 0.15 mm) was used as a protective diaphragm (electrical resistance: 1.1 Ω-cm ² ) to divide the anode chamber into two, resulting in a three-chamber structure as a whole. A spacer (polyethylene mesh) was placed in each room. The shielding rate of the spacer was 6%. The effective electrode area of both the cathode and anode is 2 dm ² .

The catholyte contains a 1 mol/mole maleic acid aqueous solution,
In the anode chamber, 1 mol/ml dissolved in 3N-sulfuric acid aqueous solution
piperidine was used. The catholyte and catholyte are circulated through two circulation tanks each at a flow rate of 50cm/sec.
When electrolyzed at 30°C with a current density of 5 A/dm ² at 100 AHr, the current efficiency at the cathode was 88% and the current efficiency at the anode was 72.
%, succinic acid 10.2%, maleic acid 1.3% respectively
% aqueous solution and a 6.1% aqueous solution of piperidine containing 2.2% glutaric acid and 0.6% succinic acid. When the amount of piperidine transferred from the anode chamber to the cathode chamber was quantified using ultraviolet absorption spectroscopy, it was found that 0.1 ppm was found in the catholyte.
It existed.

The batch experiment described above was then repeated 50 times. When the amount of piperidine in the catholyte was determined in the same manner as above after the electrolysis was completed, it was found that 3 ppm was present, and the surface treatment layer of cation exchange membrane A had hardly deteriorated.

Comparative Example 1 A lead flat plate was used as the cathode, a lead plate coated with lead peroxide was used as the anode, and a sulfonic acid type cation exchange membrane A was installed with a distance between the electrodes of 4 mm with the surface treatment layer facing the anode side. A spacer (polyethylene mesh) was interposed between each electrode and the cation exchange membrane. Note that the same spacer as in Example 1 was used. The effective electrode area of both the cathode and anode is 2 dm ² .

The catholyte contains a 1 mol/mole maleic acid aqueous solution,
In the cathode chamber, 1 mol/ml dissolved in 3N-sulfuric acid aqueous solution was added.
piperidine was used. When the catholyte and the anolyte were circulated through two circulation tanks each at a flow rate of 50 cm/sec, electrolysis was carried out at 30°C with a current density of 5 A/dm ² for 100 Ahr. The current efficiency at the electrode was 88%, and the current efficiency at the anode was 72%, respectively.
A 6.1% aqueous solution of piperidine containing 0.6% was obtained.
The amount of piperidine transferred from the anode chamber to the cathode chamber was quantified using ultraviolet absorption spectroscopy, and it was found that it was in the catholyte.
It was present at 0.1ppm.

Next, after repeating the above batch experiment 50 times,
When the amount of piperidine transferred from the anode chamber to the cathode chamber was quantified, it was found that 550 ppm was present in the catholyte.

Example 2 A sulfonic acid type cation exchange membrane C was used as a cation exchange membrane using the same three-chamber electrolyzer as in Example 1.
The surface treatment layer was installed facing the anode side using a polyethylene screen, and as a protective diaphragm, a ^Umicron (Yuasa Battery Co., Ltd. ) was used.

The catholyte contains 1 mol of oxalic acid aqueous solution, and the anode contains 1 mol of β-aminopropyl alcohol.
A 3N-sulfuric acid aqueous solution was used. The anolyte and catholyte were each passed through two circulation tanks, and the flow rates in the anode and anode chambers were adjusted to 50 cm/sec, and 100 Ahr electrolysis was carried out at 26 to 30° C. and a current density of 5 A/dm ² . The current efficiency of oxalic acid to glyoxylic acid at the cathode is 72%, and the current efficiency of β-aminopropyl alcohol to β-alanine at the anode is 81%. -alanine
A 4.7% β-aminopropyl alcohol acidic solution of 4.0% was obtained. After sampling a certain amount of catholyte and evaporating the water to dryness, quantitative analysis from an infrared absorption spectrum confirmed the presence of approximately 2 ppm of β-aminopropyl alcohol.

Next, at the end of the electrolysis after repeating the above batch experiment 30 times, β-aminopropyl alcohol in the catholyte was determined in the same manner as above, and it was found to be about 5 ppm, and the surface treatment layer of cation exchange membrane C was almost degraded. I hadn't done it.

Comparative Example 2 Using the same electrolytic device as in Comparative Example 1, a sulfonic acid type cation exchange membrane C was used as the cation exchange membrane, and the surface treatment layer was installed facing the anode side. A 1 mol oxalic acid aqueous solution was used as the catholyte, and a 3N sulfuric acid aqueous solution containing 1 mol β-aminopropyl alcohol was used as the anode. The flow rate in the negative and anode chambers was adjusted to 50 cm/sec through two circulation tanks for the anolyte and catholyte, and the current density was ⁵ A/dm2 at 26 to 30°C.
Electrolyzed with 100Ahr. The current efficiency of oxalic acid to glyoxylic acid at the cathode is 72%, and the current efficiency of β-aminopropyl alcohol to β-alanine at the anode is 81%.
% and glyoxylic acid 5.0% and 2.1% respectively
An aqueous oxalic acid solution and a 4.7% β-aminopropyl alcohol acidic solution containing 4.0% β-alanine were obtained. As a result of sampling a certain amount of catholyte and evaporating the water to dryness, we attempted to quantify it from the infrared absorption spectrum.
The presence of approximately 2 ppm of β-aminopropyl alcohol was confirmed.

Next, at the end of the electrolysis after repeating the above batch experiment 30 times, β-aminopropyl alcohol in the catholyte was determined in the same manner as above, and it was found to be approximately 450 ppm.
existed.

Example 3 Using the same three-chamber electrolyzer as in Example 1, a sulfonic acid type cation exchange membrane D was used as the cation exchange membrane.
The surface treatment layer was installed facing the anode side using a 100% carbon fiber, and asbestos cloth (electrical resistance 0.5Ω-cm ² , thickness 0.8mm) was used as a protective diaphragm. As electrodes, lead oxide was used as an anode and a tin plate was used as a cathode. α-picoline was oxidized at the anode and P-nitrosalcylic acid was reduced at the cathode.

For the anolyte, 76 g of α-picoline and 3N sulfuric acid solution 2 were used, and for the cathode, 83 g of P-nitrosalcylic acid.
Prepare solution 2 by dissolving it in 20% hydrochloric acid-ethanol (1:4) solution, and inject 100Ahr at 35℃ at 5A/ ^dm2.
Electrolytic redox was performed. The current efficiency of α-picoline to picolinic acid at the anode was 51%, and the current efficiency of P-nitrosalcylic acid to P-aminosalicylic acid at the cathode was 55%. The amount of α-picoline transferred from the anode chamber to the cathode chamber during electrolysis was 0.4 ppm based on the ultraviolet absorption spectrum.

Next, at the end of the electrolysis after repeating the above batch experiment 10 times, α-picoline in the cathode chamber was quantified in the same manner as above, and it was found to be 1.5 ppm, indicating that the surface treatment layer of cation exchange membrane D had hardly deteriorated. Nakatsuta.

Comparative Example 3 Using the same electrolytic device as Comparative Example 1, using cation exchange membrane D as the cation exchange membrane, with the surface treatment layer facing the anode side, using lead oxide as the anode and a tin plate as the cathode, Oxidation of α-picoline was carried out at the anode, and reduction of P-nitrosalcylic acid was carried out at the cathode.

Solution 2, prepared by dissolving 76 g of α-picoline in 3N sulfuric acid, was used for the anode, and solution 2, prepared by dissolving 83 g of P-nitrosalcylic acid in a 20% hydrochloric acid-ethanol (1:4) solution, was prepared for the cathode. 35℃ at ^dm2
Then, 100Ahr electrolytic redox was performed.

The current efficiency of α-picoline to picolinic acid at the anode was 51%, and the current efficiency of P-nitrosalcylic acid to P-aminosalicylic acid at the cathode was 55%. The amount of α-picoline transferred from the anode chamber to the cathode chamber by electrolysis was 0.4 ppm based on the ultraviolet absorption spectrum.

Then, at the end of the electrolysis after repeating the above batch experiment five times, the amount of α-picoline in the catholyte was determined in the same manner as above, and it was found to be 0.5%.

Comparative Example 4 Redox was carried out under exactly the same conditions as in Example 3 except that cation exchange membrane B was used. The current efficiency of α-picoline to picolinic acid was 55%, and the current efficiency of P-nitrosalcylic acid to P-aminosalicylic acid was 49%.
The amount of picoline was 1.0%.

Then, after the above batch experiment was repeated 10 times and the electrolysis was completed, the amount of α-picoline that had moved from the anode chamber to the cathode chamber was determined to be 1.0%.
The current efficiency of α-picoline to picolinic acid is 55%,
The current efficiency of P-nitrosalicylic acid to P-aminosalicylic acid was 49%.

Example 4 Electrolysis was carried out under exactly the same conditions as in Example 3 except that the oxidation reaction was not performed and only the reduction reaction was performed.
However, a 3N-sulfuric acid solution was used as the anolyte.

As a result, P of P-nitrosalcylic acid at the cathode
-The current efficiency to aminosalicylic acid was 55%.

Then, after repeating this batch experiment five times, both redox and redox reactions were carried out under exactly the same conditions as in Example 3. The current efficiency of α-picoline to picolinic acid at the anode was 51%, and the current efficiency of P-nitrosalcylic acid to P-aminosalicylic acid at the cathode was 55%. The amount of α-picoline transferred from the anode chamber to the cathode chamber during electrolysis was 1.1 ppm based on the ultraviolet absorption spectrum.

Claims (1)

[Claims] 1 The anode and the cathode are separated by a cation exchange membrane having a cationic functional group on at least one surface, and the ratio between the anode and the cation exchange membrane is Using an electrolytic cell in which an anode chamber, an intermediate chamber, and a cathode chamber are formed by dividing them by a diaphragm with an electrical resistance of 2000 Ω・cm or less, an electrolyte solution of an organic compound having a reducible functional group is poured into the cathode chamber. The organic compound is subjected to electrolytic reduction and electrolytic oxidation, characterized in that an electrolyte solution of an organic compound having an oxidizable functional group or an electrolyte solution not containing the organic compound is supplied to the anode chamber to perform electrolysis. An electrolysis method in which simultaneous or electrolytic reduction is carried out only.