JP7105418B2 - Apparatus and method for producing cis-disubstituted non-aromatic compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus and method for producing a cis-disubstituted non-aromatic compound.

Conventionally, geometric isomers of non-aromatic compounds having a non-aromatic ring substituted with two substituents are known to be industrially useful. For example, Patent Document 1 discloses a chemical process for producing a trans-4-substituted cyclohexanecarboxylic acid by reducing a 4-substituted benzoic acid with an aqueous solution in which a hydrogenation catalyst is dispersed. Trans-4-substituted cyclohexanecarboxylic acids are industrially useful as liquid crystal compounds used in liquid crystal displays.

In addition, cis isomers of non-aromatic compounds having a disubstituted non-aromatic ring, i.e., cis-disubstituted non-aromatic compounds, are also known to be useful as compounds for industrial use, particularly for pharmaceuticals and the like. . For example, cis-disubstituted cyclohexanes are useful as intermediates for pharmaceuticals.

JP-A-9-40606

The present inventors have made intensive studies on the production of the cis-disubstituted non-aromatic compounds described above, and as a result, have come up with a novel technique for producing cis-disubstituted non-aromatic compounds.

The present invention has been made in view of these circumstances, and one of its objects is to provide a novel production technique for cis-disubstituted non-aromatic compounds.

One aspect of the present invention is an apparatus for producing cis-disubstituted non-aromatic compounds. The manufacturing apparatus includes a polymer electrolyte electrolysis unit and a supply section for supplying a disubstituted aromatic compound having an aromatic ring substituted with two substituents to the polymer electrolyte electrolysis unit. The solid polymer electrolysis unit electrolytically reduces the disubstituted aromatic compound to hydrogenate the aromatic ring to produce a cis-disubstituted non-aromatic compound.

Another aspect of the invention is a method for making cis-disubstituted non-aromatic compounds. The production method uses a solid polymer type electrolytic unit to electrolytically reduce a disubstituted aromatic compound having an aromatic ring substituted with two substituents to hydrogenate the aromatic ring to obtain a cis-di Including preparing a substituted non-aromatic compound.

INDUSTRIAL APPLICABILITY According to the present invention, a novel technique for producing cis-disubstituted non-aromatic compounds can be provided.

1 is a schematic diagram showing a schematic configuration of an apparatus for producing a cis-disubstituted non-aromatic compound according to an embodiment; FIG. FIG. 2 is a cross-sectional view showing a schematic configuration of a solid polymer electrolysis unit;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on preferred embodiments with reference to the drawings. The embodiments are illustrative rather than limiting the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention. The same or equivalent constituent elements, members, and processes shown in each drawing are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience in order to facilitate the explanation, and should not be construed as limiting unless otherwise mentioned. Also, the terms such as "first" and "second" used in this specification or claims do not represent any order or degree of importance unless otherwise specified, and one configuration and another configuration. It is for distinguishing between

FIG. 1 is a schematic diagram showing a schematic configuration of an apparatus for producing a cis-disubstituted non-aromatic compound according to an embodiment. In addition, in FIG. 1, the structure of the solid polymer electrolysis unit is illustrated in a simplified manner. The cis-disubstituted non-aromatic compound production apparatus 10 is an apparatus for electrolytically reducing a di-substituted aromatic compound to produce a cis-type di-substituted non-aromatic compound. A unit 20, a substrate storage tank 30, a hydrogen storage tank 40 and a control unit 60 are provided as main components. Hereinafter, the cis-disubstituted non-aromatic compound manufacturing apparatus 10 is simply referred to as "manufacturing apparatus 10".

The power control unit 20 is, for example, a DC/DC converter that converts the output voltage of the power source into a predetermined voltage. A positive output terminal of the power controller 20 is connected to the anode 130 of the solid polymer electrolysis unit 100 . A negative output terminal of the power control unit 20 is connected to the cathode (negative electrode) 120 of the solid polymer electrolysis unit 100 . Thereby, a predetermined voltage is applied between the anode 130 and the cathode 120 of the solid polymer electrolysis unit 100 .

The power control unit 20 may be provided with reference electrodes for the purpose of detecting the potentials of the positive and negative electrodes. In this case, the reference electrode input terminal is connected to the reference electrode 112 provided on the solid polymer electrolyte membrane 110 . Reference electrode 112 is provided in a region of solid polymer electrolyte membrane 110 spaced apart from cathode 120 and anode 130 so as to be in contact with solid polymer electrolyte membrane 110 . Reference electrode 112 is electrically isolated from cathode 120 and anode 130 . Reference electrode 112 is held at the reference electrode potential. Reference electrode potential in this application shall mean the potential relative to the reversible hydrogen electrode (RHE) (reference electrode potential=0 V). The reference electrode potential may be a potential relative to the Ag/AgCl electrode (reference electrode potential=0.199 V). Note that the reference electrode 112 is preferably installed on the surface of the solid polymer electrolyte membrane 110 on the cathode 120 side.

A current detector 113 detects a current flowing between the cathode 120 and the anode 130 . The current detector 113 is composed of, for example, a conventionally known ammeter. A current value detected by the current detection unit 113 is input to the control unit 60 and used by the control unit 60 to control the power control unit 20 . A potential difference between the reference electrode 112 and the cathode 120 is detected by the voltage detector 114 . The voltage detection unit 114 is composed of, for example, a conventionally known voltmeter. The value of the potential difference detected by the voltage detection unit 114 is input to the control unit 60 and used by the control unit 60 to control the power control unit 20 . Note that the voltage detection unit 114 may detect the potential difference between the reference electrode 112 and the anode 130 as necessary.

Control unit 60 adjusts the potential of cathode 120 and/or anode 130 to a predetermined potential. The control unit 60 is realized by elements and circuits such as a CPU and a memory of a computer as a hardware configuration, and is realized by a computer program etc. as a software configuration. This is naturally understood by those skilled in the art. The control unit 60 controls outputs of the positive output terminal and the negative output terminal of the power control unit 20 so that the potential of the cathode 120 and/or the anode 130 becomes a predetermined potential. Also, the control unit 60 controls the output of the power control unit 20 so that the current density at the cathode 120 and/or the anode 130 becomes a predetermined value.

The substrate storage tank 30 stores a disubstituted aromatic compound as a substrate. A disubstituted aromatic compound is a compound having at least one aromatic ring substituted with two substituents (hereinafter, appropriately referred to as a disubstituted aromatic ring). Disubstituted aromatic compounds include disubstituted aromatic hydrocarbon compounds and disubstituted nitrogen-containing heterocyclic aromatic compounds. Examples of aromatic rings possessed by aromatic hydrocarbon compounds include benzene, naphthalene, anthracene, and diphenylethane. These may be used alone or in combination. Examples of the nitrogen-containing heterocyclic ring contained in the nitrogen-containing heterocyclic aromatic compound include pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, N-alkylpyrrole, N-alkylindole, and N-alkyldibenzopyrrole. These may be used alone or in combination. Moreover, the aromatic hydrocarbon compound and the nitrogen-containing heterocyclic aromatic compound may be used alone or in combination.

The aromatic ring contained in the aromatic hydrocarbon compound and the heteroaromatic ring contained in the nitrogen-containing heterocyclic aromatic compound are substituted with two substituents. Thus, disubstituted aromatic rings include disubstituted aromatic rings and disubstituted heteroaromatic rings. The types of substituents are not particularly limited, but examples include alkyl groups, amino groups, hydroxyl groups, carboxyl groups, nitro groups, esters, amides, ethers, and halogens. The two substituents may be the same or different. Moreover, the positions of the two substituents may be any of the ortho, meta and para positions.

The substrate may be diluted with a solvent when the substrate cannot be subjected to the electrolytic reaction as it is, such as when the substrate is solid at room temperature or when the viscosity is high. A solvent is not particularly limited. However, if the solvent adheres to the electrode or is reduced in the electrolytic reaction, the electrolytic reaction of the substrate may be inhibited. Therefore, it is preferable that the solvent can deliver the substrate to the reaction point without inhibiting the electrolytic reaction of the substrate. If the substrate is liquid at room temperature and has low viscosity to the extent that it can be subjected to electrolytic reaction, the solvent can be omitted.

The disubstituted aromatic compound stored in the substrate storage tank 30 is supplied to the cathode 120 of the solid polymer electrolysis unit 100 by the first supply device 32 . The substrate storage tank 30 and the first supply device 32 constitute a supply section 34 that supplies the disubstituted aromatic compound to the solid polymer electrolysis unit 100 . As the first supply device 32, for example, various pumps such as a gear pump or a cylinder pump, or a gravity flow type device can be used.

A circulation path 36 is provided between the substrate reservoir 30 and the cathode 120 . The circulation path 36 includes an outward path portion 36a that connects the substrate storage tank 30 and the cathode 120 on the upstream side of the cathode 120 in the substrate flow, and connects the cathode 120 and the substrate storage tank 30 on the downstream side of the cathode 120 in the substrate flow. and a return path portion 36b. A first supply device 32 is provided in the middle of the outward path portion 36a.

The supply section 34 supplies the disubstituted aromatic compound to the cathode 120 via the forward path section 36a. The reduced product of the disubstituted aromatic compound reduced at the cathode 120 and the unreacted disubstituted aromatic compound are returned to the substrate storage tank 30 via the return route section 36b. Although no gas is generated in the main reaction proceeding at the cathode 120, if a gas such as hydrogen is by-produced, gas-liquid separation means may be provided in the middle of the return path portion 36b. Also, the return path portion 36b may not be provided.

The hydrogen storage tank 40 stores, for example, humidified hydrogen gas. Hereinafter, humidified hydrogen gas is simply referred to as "hydrogen gas" as appropriate. The dew point temperature of hydrogen gas is, for example, room temperature to 100°C, more preferably 50 to 100°C. The hydrogen gas stored in the hydrogen storage tank 40 is supplied to the anode 130 of the solid polymer electrolysis unit 100 by the second supply device 42 . As the second supply device 42, for example, various gas flow controllers, gravity flow devices, or the like can be used.

A circulation path 44 is provided between the hydrogen storage tank 40 and the anode 130 . The circulation path 44 includes an outward path portion 44a that connects the hydrogen storage tank 40 and the anode 130 upstream of the anode 130 in the flow of hydrogen gas, and an outflow portion 44a that connects the anode 130 and the hydrogen storage tank 40 on the downstream side of the anode 130 in the flow of hydrogen gas. and a return path portion 44b that connects the . A second supply device 42 is provided in the middle of the forward path portion 44a.

Hydrogen gas is supplied to the anode 130 via the forward path portion 44a. Unreacted hydrogen gas in the anode 130 is returned to the hydrogen storage tank 40 via the return path portion 44b. Note that the return path portion 44b may not be provided.

FIG. 2 is a cross-sectional view showing a schematic configuration of the solid polymer electrolysis unit 100. As shown in FIG. The polymer electrolyte electrolysis unit 100 of the present embodiment is a polymer electrolyte cell having an anode chamber on one side and a cathode chamber on the other side of a film-shaped electrolyte membrane. More specifically, the solid polymer electrolysis unit 100 includes a membrane electrode assembly 102 and a pair of separators 150a and 150b that sandwich the membrane electrode assembly 102 therebetween. The membrane electrode assembly 102 has a solid polymer electrolyte membrane 110 , a cathode 120 and an anode 130 .

A solid polymer electrolyte membrane 110 is provided between the anode 130 and the cathode 120 . Solid polymer electrolyte membrane 110 is made of a material having proton conductivity (ionomer). The solid polymer electrolyte membrane 110 selectively conducts protons while suppressing mixing and diffusion of substances between the cathode 120 and the anode 130 . The thickness of the solid polymer electrolyte membrane 110 is, for example, 5 to 300 μm. By setting the thickness of the solid polymer electrolyte membrane 110 to 5 μm or more, the barrier properties of the solid polymer electrolyte membrane 110 can be ensured, and cross-leakage of disubstituted aromatic compounds and the like can be more reliably suppressed. can. Further, by setting the thickness of the solid polymer electrolyte membrane 110 to 300 μm or less, it is possible to suppress the ion transfer resistance from becoming excessively large.

Solid polymer electrolyte membrane 110 preferably contains perfluorosulfonic acid as a material having proton conductivity. For example, the solid polymer electrolyte membrane 110 is made of perfluorosulfonic acid polymer. Examples of the polymer include Nafion (registered trademark) and Flemion (registered trademark). The solid polymer electrolyte membrane 110 may be mixed with a reinforcing material such as porous PTFE (polytetrafluoroethylene). By introducing a reinforcing material, the dimensional stability of the solid polymer electrolyte membrane 110 can be enhanced. Thereby, the durability of the solid polymer electrolyte membrane 110 can be improved. In addition, crossover of disubstituted aromatic compounds and the like can be suppressed.

Cathode 120 is an electrode for reducing a disubstituted aromatic compound to produce a cis-disubstituted non-aromatic compound, and is arranged on one side of solid polymer electrolyte membrane 110 . In this embodiment, cathode 120 is provided so as to be in contact with one main surface of solid polymer electrolyte membrane 110 . The cathode 120 has a structure in which a cathode catalyst layer 122 and a diffusion layer 124 are laminated. The cathode catalyst layer 122 is arranged closer to the solid polymer electrolyte membrane 110 than the diffusion layer 124 is.

Cathode catalyst layer 122 is in contact with one main surface of solid polymer electrolyte membrane 110 . Cathode catalyst layer 122 contains a catalytic metal for hydrogenating the disubstituted aromatic ring of the disubstituted aromatic compound with protons. Preferably, cathode catalyst layer 122 contains at least one element selected from the group consisting of Pt, Pd, Rh, Ru and Ir as a catalyst. By containing these catalytic elements in the cathode catalyst layer 122, the cis-disubstituted non-aromatic compound can be produced with high selectivity.

The catalytic element is carried by a catalytic carrier made of an electronically conductive material. The surface area of the cathode catalyst layer 122 can be increased by supporting the catalyst element on the catalyst carrier. Also, aggregation of the catalyst element can be suppressed. The electron conductivity of the electron conductive material used for the catalyst carrier is preferably 1.0×10 ⁻² S/cm or more. By setting the electron conductivity of the electron conductive material to 1.0×10 ⁻² S/cm or more, electron conductivity can be imparted to the cathode catalyst layer 122 more reliably.

Examples of the catalyst carrier include electron conductive materials containing porous carbon, porous metal, or porous metal oxide as a main component. Examples of porous carbon include carbon black such as Ketjenblack (registered trademark), acetylene black, furnace black, and Vulcan (registered trademark). Porous metals include, for example, Pt black, Pd black, and fractally deposited Pt metal. Porous metal oxides include oxides of Ti, Zr, Nb, Mo, Hf, Ta and W, for example. In addition, the catalyst carrier includes porous metal compounds such as nitrides, carbides, oxynitrides, carbonitrides, and partially oxidized carbonitrides of metals such as Ti, Zr, Nb, Mo, Hf, Ta, and W. can also be used.

The catalyst carrier supporting the catalyst element is coated with an ionomer. Thereby, the ion conductivity of the cathode 120 can be improved. Examples of ionomers include perfluorosulfonic acid polymers such as Nafion (registered trademark) and Flemion (registered trademark). The ionomer contained in the cathode catalyst layer 122 preferably partially covers the catalyst element. According to this, the three elements (disubstituted aromatic compound, protons, and electrons) necessary for the electrochemical reaction in the cathode catalyst layer 122 can be efficiently supplied to the reaction field.

The thickness of the cathode catalyst layer 122 is, for example, 1-100 μm. By setting the thickness of the cathode catalyst layer 122 within the above range, an increase in proton transfer resistance can be suppressed, and the diffusibility of the disubstituted aromatic compound can be maintained.

The cathode catalyst layer 122 is formed by, for example, mixing a catalyst component powder, a solvent such as water, and an ionomer to prepare a catalyst ink, applying the obtained catalyst ink to the diffusion layer 124, drying it, and hot-pressing it. can be made. In addition, it is preferable to perform the hot pressing after applying and drying the catalyst ink in a plurality of times. Thereby, a more homogeneous cathode catalyst layer 122 can be obtained. Also, the cathode catalyst layer 122 may be formed on the solid polymer electrolyte membrane 110 .

The diffusion layer 124 has a function of uniformly diffusing the disubstituted aromatic compound supplied from the separator 150 a to the cathode catalyst layer 122 . The material forming the diffusion layer 124 preferably has a high affinity for the disubstituted aromatic compound. Examples of the material forming the diffusion layer 124 include carbon woven fabric (carbon cloth), carbon nonwoven fabric, and carbon paper. The carbon cloth is made by bundling hundreds of carbon fibers with a diameter of several micrometers into a woven fabric. Carbon paper is obtained by sintering a thin film precursor made from carbon raw material fibers by a papermaking method. The thickness of the diffusion layer 124 is preferably 50-1000 μm.

Cathode 120 may have a dense layer (not shown) between cathode catalyst layer 122 and diffusion layer 124 . The dense layer has a function of promoting diffusion of the disubstituted aromatic compound in the surface direction of the cathode catalyst layer 122 . In particular, by providing the dense layer, the disubstituted aromatic compound can be diffused directly under the region of the diffusion layer 124 that is in direct contact with the separator 150a.

Separator 150 a is laminated on the main surface of cathode 120 opposite to solid polymer electrolyte membrane 110 . The separator 150a is made of, for example, a carbon resin, or a corrosion-resistant material such as a Cr--Ni--Fe system, a Cr--Ni--Mo--Fe system, a Cr--Mo--Nb--Ni system, a Cr--Mo--Fe--W--Ni system, or a Ti system. It can be made of an alloy. A surface of the separator 150a on the diffusion layer 124 side is provided with one or a plurality of groove-like flow paths 152a. The forward path portion 36a and the return path portion 36b are connected to the flow path 152a. A cathode chamber is defined by the separator 150a, the solid polymer electrolyte membrane 110, and the frame-like spacer 126 arranged therebetween, and the cathode catalyst layer 122 and the diffusion layer 124 are accommodated in the cathode chamber.

The disubstituted aromatic compound flows into the channel 152a of the cathode chamber via the outward channel portion 36a. The disubstituted aromatic compound permeates into the diffusion layer 124 from the channel 152a. The product of the electrolytic reduction reaction in the cathode catalyst layer 122 and the unreacted disubstituted aromatic compound flow out of the cathode chamber through the return path portion 36b and are returned to the substrate storage tank 30 . The form of the channel 152a is not particularly limited, but for example, a linear channel, a serpentine channel, or the like can be adopted. Alternatively, the separator 150a may have a porous layer, and the flow paths 152a may be formed by voids in the porous layer.

Anode 130 is an electrode for generating protons from hydrogen gas, and is arranged on one side of solid polymer electrolyte membrane 110, that is, on the side opposite to the side where cathode 120 is arranged. Anode 130 has a structure in which anode catalyst layer 132 and diffusion layer 134 are laminated. The anode catalyst layer 132 is arranged closer to the solid polymer electrolyte membrane 110 than the diffusion layer 134 is.

Anode catalyst layer 132 is in contact with the other main surface of solid polymer electrolyte membrane 110 . Anode catalyst layer 132 contains a catalyst metal for producing protons from hydrogen gas. For example, the anode catalyst layer 132 contains at least one element selected from the group consisting of Ru, Rh, Pd, Ir and Pt as a catalyst. The catalytic element may be dispersedly supported or coated on a metal substrate having electronic conductivity. Such metal substrates include metals such as Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ta, and W, or alloys containing these as main components. Metal fibers (fiber diameter: eg 10 to 30 μm), meshes (mesh diameter: eg 500 to 1000 μm), sintered metal porous bodies, foams, expanded metals and the like can be mentioned. The thickness of the anode catalyst layer 132 is, for example, 0.1 to 10 μm.

The diffusion layer 134 has a function of uniformly diffusing the hydrogen gas supplied from the separator 150 b to the anode catalyst layer 132 . Examples of the material forming the diffusion layer 134 include carbon woven fabric (carbon cloth), carbon nonwoven fabric, and carbon paper. The thickness of the diffusion layer 134 is preferably 50-1000 μm.

Separator 150 b is laminated on the main surface of anode 130 opposite to solid polymer electrolyte membrane 110 . Separator 150b can be made of the same material as separator 150a. A surface of the separator 150b on the diffusion layer 134 side is provided with one or a plurality of groove-like flow paths 152b. The forward path portion 44a and the return path portion 44b are connected to the flow path 152b. An anode chamber is defined by the separator 150b, the solid polymer electrolyte membrane 110, and the frame-shaped spacer 136 arranged therebetween, and the anode catalyst layer 132 and the diffusion layer 134 are accommodated in the anode chamber.

Hydrogen gas flows into the flow path 152b of the anode chamber via the forward path portion 44a. Hydrogen gas permeates into the diffusion layer 134 from the channel 152b. The unreacted hydrogen gas flows out of the anode chamber through the return path portion 44b and is returned to the hydrogen storage tank 40. FIG. The form of the channel 152b is similar to that of the channel 152a. Instead of hydrogen gas, the anode 130 may contain ion-exchanged water, pure water, or an aqueous solution obtained by adding an acid such as sulfuric acid, phosphoric acid, nitric acid, or hydrochloric acid (hereinafter, these are collectively referred to as "anolyte"). ) may be supplied. In this case, the anode catalyst layer 132 oxidizes water in the anolyte to produce protons. By supplying the anolyte instead of hydrogen gas, the manufacturing apparatus 10 can be simplified.

The solid polymer electrolysis unit 100 electrolytically reduces the disubstituted aromatic compound to hydrogenate the disubstituted aromatic ring to produce a cis-disubstituted non-aromatic compound. The reactions in the polymer electrolyte unit 100 when p-xylene is used as the disubstituted aromatic compound are as follows.
<Electrode reaction at anode 130>
H ₂ →2H ⁺ +2e ⁻ : E ₀ =0V
<Electrode reaction at cathode 120>
p-xylene + 6H ⁺ +6e ^- → 1,4-dimethylcyclohexane: E ₀ = +0.10V
<Total reaction>
p-xylene + 3H ₂ → 1,4-dimethylcyclohexane

That is, the electrode reaction at the anode 130 and the electrode reaction at the cathode 120 proceed in parallel. Protons generated at the anode 130 are supplied to the cathode 120 through the solid polymer electrolyte membrane 110 . The protons supplied to the cathode 120 are utilized at the cathode 120 for reduction of p-xylene, which is a disubstituted aromatic compound.

In the electrode reaction at the cathode 120, the reduction of p-xylene can produce cis- and trans-forms of 1,4-dimethylcyclohexane as disubstituted non-aromatic compounds. According to the production apparatus 10 of the present embodiment, cis-1,4-dimethylcyclohexane can be produced with high selectivity.

Further, when the cathode catalyst layer 122 contains Pt or Ru, more preferably when the cathode catalyst layer 122 contains Ru, cis-1,4-dimethylcyclohexane can be produced with higher selectivity. Moreover, as a more preferable aspect, the controller 60 adjusts the current density of the cathode 120 to 25 mA/cm ² or less. This can improve the current efficiency when producing cis-1,4-dimethylcyclohexane.

[Method for producing cis-disubstituted non-aromatic compound]
In the method for producing a cis-disubstituted non-aromatic compound according to the present embodiment, the solid polymer electrolysis unit 100 is used to electrolytically reduce the disubstituted aromatic compound to hydrogenate the disubstituted aromatic ring, including producing a cis-disubstituted non-aromatic compound. More specifically, hydrogen gas is supplied to the anode catalyst layer 132 of the anode 130 . Also, a disubstituted aromatic compound is supplied to the cathode catalyst layer 122 of the cathode 120 . A predetermined voltage is applied between the anode 130 and the cathode 120 of the solid polymer electrolysis unit 100 by the power control unit 20 .

As a result, protons are generated in the anode catalyst layer 132 . The produced protons pass through the solid polymer electrolyte membrane 110 and move to the cathode 120 side. In the cathode catalyst layer 122, protons that have passed through the solid polymer electrolyte membrane 110 hydrogenate the disubstituted aromatic ring to produce a cis-disubstituted non-aromatic compound. The process of producing protons and the process of producing cis-disubstituted non-aromatic compounds by electrolytic reduction reaction occur at least temporarily in parallel.

As described above, the apparatus 10 for producing a cis-disubstituted non-aromatic compound and the method for producing a cis-disubstituted non-aromatic compound according to the present embodiment are capable of producing a disubstituted aromatic compound by the solid polymer electrolysis unit 100. electroreduction of a group compound to produce a cis-disubstituted non-aromatic compound. Therefore, according to this embodiment, a novel technique for producing cis-disubstituted non-aromatic compounds can be obtained.

In conventional chemical processes, it was common to mix a disubstituted aromatic compound as a substrate into a solution in which a catalyst is dispersed to produce a cis-disubstituted non-aromatic compound. This process required a step of separating the catalyst and product in solution after the reaction. On the other hand, in the present embodiment, the solid polymer type electrolysis unit 100 is used, so the step of separating the catalyst and the product can be omitted. Therefore, the production process of the cis-disubstituted non-aromatic compound can be simplified.

In addition, the conventional chemical process produced a high proportion of trans-disubstituted non-aromatic compounds. This made it difficult to separate the cis-disubstituted non-aromatic compound from the product. On the other hand, according to the present embodiment, the cis-disubstituted non-aromatic compound can be produced with high selectivity, so that the cis-disubstituted non-aromatic compound can be easily separated from the product.

Further, according to the present embodiment, cis-disubstituted non-aromatic compounds can be produced with high selectivity under mild conditions of 50° C. and normal pressure. Therefore, the occurrence of side reactions can be suppressed. In addition, by using the solid polymer type electrolysis unit 100, the size of the electrolytic cell can be reduced as compared with liquid type electrolysis. Also, the overvoltage at the cathode 120 can be reduced. Therefore, easier potential control is possible. Since potential control becomes easier, more accurate potential control is also possible.

Moreover, the cathode catalyst layer 122 of the solid polymer electrolysis unit 100 preferably contains at least one element selected from the group consisting of Pt, Pd, Rh, Ru and Ir. As a result, cis-disubstituted non-aromatic compounds can be produced with high selectivity compared to trans-disubstituted non-aromatic compounds. Further, in this embodiment, hydrogen gas is supplied to the anode 130 . Therefore, the potential of the anode 130 becomes 0 V (vs. RHE). Therefore, anode 130 can be used as a substitute for reference electrode 112 . Therefore, the reference electrode 112 can be omitted.

EXAMPLES Examples of the present invention will be described below, but the examples are merely examples for suitably explaining the present invention, and do not limit the present invention in any way.

(Example 1)
<Preparation of Anode>
Nafion (registered trademark) dispersion DE2020 (manufactured by DuPont) was added to the powder of Pt/C catalyst (product number: TEC10E50E, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) in which platinum was supported on porous carbon as a catalyst carrier and platinum as a catalyst metal. was added, and a solvent was appropriately used to prepare a catalyst ink for an anode catalyst layer. The Nafion (registered trademark) dispersion liquid was added in an amount such that the mass ratio of Nafion (registered trademark) after drying to the carbon in the catalyst was 0.8:1.

A diffusion layer (product name: SGL35BC, manufactured by SGL Carbon Co., Ltd.) having a size of 4 cm ² was also prepared. Then, the prepared catalyst ink was spray-coated on one main surface of the diffusion layer. The catalyst ink was applied so that the mass of Pt per electrode area was 0.5 mg/cm ² . After that, the diffusion layer coated with the catalyst ink was dried at 80° C. to remove the solvent component in the catalyst ink. Subsequently, thermal bonding was performed at 120° C. and 0.4 MPa for 1 minute to obtain a first laminate comprising an anode catalyst layer and a diffusion layer.

<Production of cathode>
A catalyst ink for the cathode catalyst was prepared in the same manner as the anode, the catalyst ink was spray-coated on the diffusion layer, thermal bonding was performed, and a second laminate consisting of the cathode catalyst layer and the diffusion layer was formed. Obtained.

<Fabrication of membrane electrode assembly>
A solid polymer electrolyte membrane (product name: Nafion (registered trademark) 212, manufactured by DuPont) having a thickness of 50 μm was prepared. Then, this electrolyte membrane was sandwiched between the first laminate and the second laminate, and thermally bonded for 1 minute under conditions of 120° C. and 0.4 MPa. As a result, a membrane electrode assembly (MEA) comprising a diffusion layer, a cathode catalyst layer, a solid polymer electrolyte membrane, an anode catalyst layer and a diffusion layer was obtained.

<Measurement of product>
The MEA was pretreated by flowing humidified nitrogen to the cathode side of the MEA and humidified hydrogen to the anode side at a flow rate of 100 mL/min for 1 hour. The dew points of humidified nitrogen and humidified hydrogen were each set to 50°C. After pretreatment, a catholyte solution consisting of p-xylene as a substrate was passed through the cathode side of the MEA. The catholyte solution was passed at a flow rate of 0.25 mL/min using a syringe. Further, humidified hydrogen was continuously passed through the anode side at a flow rate of 100 mL/min. Then, a predetermined current was applied to the MEA to perform constant current electrolysis for 20 minutes. The current density at the cathode was set to the values shown in Table 1.

After constant current electrolysis, a gas chromatograph (GC) (product name: GC-2014, manufactured by Shimadzu Corporation, detector FID) was used to quantify reaction products contained in the catholyte solution. From the obtained molar ratio of each product, the current efficiency (%) of the product was calculated as the ratio of the current used to generate each product in the current applied in constant current electrolysis. Table 1 shows the results. In addition, the ratio (cis/trans) between the molar fraction of the trans isomer and the molar fraction of the cis isomer was calculated. Table 1 shows the results.

(Example 2)
An MEA was produced in the same manner as in Example 1, except that Ru/CB was used instead of Pt/C for the cathode catalyst layer, and the current efficiency (%) of the product and the ratio of the trans- and cis-isomers was calculated. Table 1 shows the results. Ru/CB was prepared by the following procedure. First, RuCl ₂ and carbon black (CB) were dispersed in pure water, and the resulting solution was subjected to ultrasonic treatment at 60° C. for 30 minutes. The solution was then dried up. After drying the obtained sample at 60° C. overnight, hydrogen reduction was performed at 350° C. to obtain Ru/CB. The concentration of Ru in Ru/CB was determined by thermogravimetric analysis to be 27% by mass.

(Example 3)
MEA in the same manner as in Example 1, except that PtRu/C (product number: TEC61E54, Pt21.6 wt%, Ru32.4 wt%, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was used instead of Pt/C for the cathode catalyst layer. was prepared, and the current efficiency (%) of the product and the ratio of the trans-isomer and the cis-isomer were calculated. Table 1 shows the results.

(Example 4)
An MEA was prepared in the same manner as in Example 1, except that Rh/CB was used instead of Pt/C for the cathode catalyst layer, and the current efficiency (%) of the product and the ratio of the trans- and cis-isomers was calculated. Table 1 shows the results. Rh/CB was prepared by the following procedure. First, RhCl ₂ and carbon black (CB) were dispersed in pure water, and the resulting solution was subjected to ultrasonic treatment at 60° C. for 30 minutes. The solution was then dried up. The resulting sample was dried at 60°C overnight and then hydrogen-reduced at 350°C to obtain Rh/CB. The concentration of Rh in Rh/CB was 29% by weight as determined by thermogravimetric analysis.

As shown in Table 1, it was confirmed from Examples 1 to 4 that cis-disubstituted non-aromatic compounds can be produced with high selectivity by electrolytic reduction of disubstituted aromatic compounds. It was also confirmed that when the cathode contains Pt or Ru as the catalyst metal, the selectivity of the cis-disubstituted non-aromatic compound is higher than when it contains Rh. Further, from Examples 1 to 3, it was confirmed that the selectivity of cis-disubstituted non-aromatic compounds was further improved when Ru was included as the catalytic metal of the cathode. Moreover, it was confirmed from Examples 2 and 3 that the selectivity of cis-disubstituted non-aromatic compounds is further improved when the proportion of Ru is high.

In addition, from Examples 1 to 4, when Pt is included as the cathode catalyst metal, the current efficiency in producing a cis-disubstituted non-aromatic compound tends to be higher than when Ru or Rh is included. was confirmed. Further, from Examples 1, 3, and 4, it was confirmed that the current efficiency in producing the cis-disubstituted non-aromatic compound tends to increase when the current density is 25 mA/cm ² or less. Further, from Example 2, when only Ru is included as the catalyst metal of the cathode, even when the current density is 25 mA/cm ² or more, the current efficiency in producing the cis-disubstituted non-aromatic compound was confirmed to be able to be maintained.

The reason why the total current efficiency of each product in Table 1 is not 100% is that part of the current was used to generate hydrogen gas. Further, those skilled in the art will know from the results of Examples 1 to 4 using Pt, Ru and Rh as catalytic metals for the cathode that similar results can be obtained when Pd and Ir are used as catalytic metals. I can understand.

The present invention is not limited to the above-described embodiments, and modifications such as various design changes can be made based on the knowledge of those skilled in the art. can also be included in the scope of the present invention.

Any combination of the constituent elements described in the embodiments and conversion of expressions of the present invention between methods, devices, systems, etc. are also effective as aspects of the present invention.

REFERENCE SIGNS LIST 10 manufacturing apparatus 34 supply unit 100 solid polymer electrolysis unit 110 solid polymer electrolyte membrane 120 cathode 122 cathode catalyst layer 130 anode 132 anode catalyst layer.

Claims (5)

a polymer electrolyte electrolysis unit having a membrane electrode assembly;
a supply unit for supplying a disubstituted aromatic compound having an aromatic ring substituted with two substituents to the polymer electrolyte electrolysis unit;
The membrane electrode assembly has an anode including an anode catalyst layer, a cathode including a cathode catalyst layer, and a solid polymer electrolyte membrane provided between the anode and the cathode,
The solid polymer electrolysis unit electrolytically reduces the disubstituted aromatic compound to hydrogenate the aromatic ring to produce a cis-disubstituted non-aromatic compound ,
An apparatus for producing a cis-disubstituted non-aromatic compound, wherein the di-substituted aromatic compound is p-xylene, and the cis-disubstituted non-aromatic compound is cis-1,4-dimethylcyclohexane . 2. The apparatus for producing a cis-disubstituted non-aromatic compound according to claim 1, wherein the supply unit supplies the disubstituted aromatic compound to the cathode. 3. The apparatus for producing a cis-disubstituted non-aromatic compound according to claim 1, wherein said cathode catalyst layer contains at least one element selected from the group consisting of Pt, Pd, Rh, Ru and Ir. 4. The apparatus for producing a cis-disubstituted non-aromatic compound according to claim 1, wherein the solid polymer electrolyte membrane contains perfluorosulfonic acid. Using a solid polymer electrolysis unit comprising a membrane electrode assembly having an anode containing an anode catalyst layer, a cathode containing a cathode catalyst layer, and a solid polymer electrolyte membrane provided between the anode and the cathode electrolytically reducing a disubstituted aromatic compound having an aromatic ring substituted with two substituents to hydrogenate the aromatic ring to produce a cis- disubstituted non-aromatic compound. ,
A method for producing a cis-disubstituted non-aromatic compound, wherein the di-substituted aromatic compound is p-xylene, and the cis-disubstituted non-aromatic compound is cis-1,4-dimethylcyclohexane .

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