METHOD FOR ELECTROLYTIC REDUCTION OF ACRYLONITRILE TO PRODUCE ADIPONITRILE AND HEXANETRICARBONITRILE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 202411243104.5, filed on Sep. 5, 2024, the contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to the field of electrochemical technology, specifically to a method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile.

BACKGROUND

Adiponitrile (AND), with the CAS number: 111-69-3, molecular formula: C₆H₃N₂, molecular weight: 108.14, boiling point: 295 degrees Celsius (° C.), is an important organic chemical intermediate primarily used in the production of materials such as polyamide 66 (PA66), 1,6-hexamethylene diisocyanate (HDI), and polyhexamethylene sebacamide (PA610). With technological advancements, the application fields of adiponitrile have gradually expanded, and adiponitrile is now used in the synthesis of high-quality, environmentally friendly coatings, polymer additives, electroplating additives, extractants, etc.

1,3,6-hexanetricarbonitrile (HTCN), with the CAS number: 1772-25-4, molecular formula: C₉H₁₁N₃, molecular weight: 161.20, boiling point: 441° C., is an excellent electrolyte additive. As an environmentally friendly polar aprotic solvent, hexanetricarbonitrile exhibits advantages such as low viscosity, high boiling point, wide electrochemical window, and high chemical stability. Moreover, the decomposition products of hexanetricarbonitrile in solvents are generally carboxylates, aldehydes, and organic amines, rather than highly toxic CN⁻. Therefore, hexanetricarbonitrile is increasingly recognized as an important intermediate for industrial organic synthesis and lithium-ion battery electrolyte additives.

Currently, the electrolytic preparation of adiponitrile from acrylonitrile is widely adopted. While producing adiponitrile, this method may also yield hexanetricarbonitrile, which has extremely high added value. The electrolytic preparation of adiponitrile from acrylonitrile offers advantages, such as abundant raw material sources, low cost, simple process, mild reaction conditions, and safe and controllable reaction processes. However, in the diaphragm-free electrolysis of acrylonitrile, oxygen is generated at the anode and a small amount of hydrogen is produced at the cathode. The explosive range for oxygen and hydrogen mixtures is 4.0-95%. In sealed or semi-scaled electrolytic environments, it may easily form explosive gas mixtures. If the mixed gas is exposed to ignition sources, such as high temperatures or electrical sparks, explosions may occur, causing serious damage to production facilities, personnel safety, and the environment. Additionally, the explosive range for acrylonitrile gas is between 3.05-17.5%. During electrolysis, a certain amount of acrylonitrile evaporates into the reaction system. The mixture of acrylonitrile volatile gas and by-product oxygen may reach the explosive range, resulting in an increased risk of accidents. Therefore, improving the safety of the electrolytic reaction has become a critical technical challenge for professionals in this field.

SUMMARY

The objective of the present disclosure is to provide a method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile, addressing the problems existing in the prior art. The method according to the present disclosure enables the co-production of adiponitrile and hexanetricarbonitrile, solving the problem in existing electrochemical synthesis technologies, where the focus is solely on adiponitrile output and treating the high-value-added hexanetricarbonitrile as waste. Furthermore, by adding easily oxidizable substances, such as methanol, the present disclosure reduces the anode oxidation potential, suppresses oxygen generation, inhibits the occurrence of oxygen evolution reactions, enhances reaction stability and safety, lowers cell voltage, improves current efficiency, and reduces energy consumption, thereby lowering production costs.

To achieve the above objective, the present disclosure provides the following technical solution.

The technical solution of the present disclosure is to provide a method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile, including the following steps:

• • mixing acrylonitrile with an electrolyte solution and then performing electrolytic reduction to obtain the adiponitrile and the hexanetricarbonitrile (1,3,6-hexanetricarbonitrile);
  • where components of the electrolyte solution include: a supporting electrolyte, an electrode protector, a complexing agent, a quaternary ammonium salt, and an easily oxidizable substance.

In an embodiment, a concentration of the supporting electrolyte in the electrolyte solution is 7.5-12.5 percent by weight (wt. %), and the supporting electrolyte includes a phosphate;

• • a concentration of the electrode protector in the electrolyte solution is 1-4 wt. %, and the electrode protector includes borax;
  • a concentration of the complexing agent in the electrolyte solution is 0.5-1.5 wt. %, and the complexing agent includes ethylene diamine tetraacetic acid (EDTA); and
  • a concentration of the quaternary ammonium salt in the electrolyte solution is 0.5-2.5 wt. %.

In an embodiment, the phosphate includes disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, or potassium dihydrogen phosphate; and

the quaternary ammonium salt includes tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide.

In an embodiment, a concentration of the acrylonitrile in the electrolyte solution is 7.5-15 wt. %; and

• • the easily oxidizable substance includes methanol, formaldehyde, formic acid, ethanol, acetaldehyde, acetic acid, oxalic acid, glyoxal, ethylene glycol, or glycerol.

In an embodiment, a concentration of the easily oxidizable substance in the electrolyte solution is 0.1-5.0 moles per liter (mol/L).

In an embodiment, a concentration of the easily oxidizable substance in the electrolyte is 1 mol/L.

The function of borax in the present disclosure is to alleviate the corrosion of the electrolyte on the electrode, the function of the complexing agent is to prevent the deposition of metal ions, the function of the quaternary ammonium salt is to enhance the conductivity of the electrolyte and increase the solubility of acrylonitrile, the function of the easily oxidizable substance is to replace oxygen evolution reactions with anodic oxidation.

In an embodiment, a temperature for the electrolytic reduction is 20-50 degrees Celsius (° C.), a current density is 500-5000 amperes per square meter (A/m²), and an electric charge is 0.5-0.9 Faraday per mole (F/mol).

In an embodiment, a distance between a cathode and an anode during the electrolytic reduction is 0.1-5 millimeters (mm);

A material of the cathode includes any one of cadmium (Cd), lead (Pb), and a cadmium-lead alloy (70% lead and 30% cadmium), and a material of the anode includes any one of carbon steel, stainless steel (such as 304 stainless steel), nickel, and titanium-based iridium oxide.

The electrode prepared using titanium-based iridium oxide as electrode material is a dimensionally stable anode (DSA) electrode.

In an embodiment, the distance between the cathode and the anode during the electrolytic reduction is 0.5-5 mm.

In an embodiment, a linear velocity of the electrolyte during the electrolytic reduction is 0.02-1.5 meters per second (m/s).

In an embodiment, the linear velocity of the electrolyte during the electrolytic reduction is 0.1-0.5 m/s.

In an embodiment, a potential of Hydrogen (pH) value of the electrolyte is 7.5-8.

The present disclosure discloses the following technical effects.

The method according to the present disclosure enables the co-production of adiponitrile and hexanetricarbonitrile, solving the problem in existing electrochemical synthesis technologies where the focus is solely on adiponitrile output, while treating hexanetricarbonitrile with high added value as waste.

Under conditions of low linear velocity and high acrylonitrile content, the present disclosure significantly improves the yield and overall current efficiency of adiponitrile and 1,3,6-hexanetricarbonitrile by adjusting the distance between electrode plates. The replacement of the oxygen evolution reaction with methanol oxidation at the anode suppresses oxygen generation, eliminating the risk of explosive gas mixtures formed by oxygen, hydrogen, and acrylonitrile, thereby enhancing the stability and safety of the diaphragm-free electrolysis process. Additionally, the anode potential, cell voltage, and energy consumption during electrolysis are reduced, making the acrylonitrile electrolysis process safer and more energy-efficient, with significant economic benefits and application value.

By introducing easily oxidizable substances such as methanol, formaldehyde, formic acid, ethanol, acetaldehyde, acetic acid, oxalic acid, glyoxal, ethylene glycol, and glycerol into the electrolysis process, the present disclosure suppresses the oxygen evolution reaction at the anode. Instead of transferring 4 moles (mol) of electrons to produce 1 mol of oxygen, the process now transfers 6 mol of electrons to produce 1 mol of carbon dioxide, greatly reducing oxygen generation, avoiding the problem of explosive gas mixtures formed by volatile gases such as oxygen, hydrogen, and acrylonitrile, improving the safety of the diaphragm-free electrolytic cell reaction and making the reaction process of acrylonitrile electrolysis to produce adiponitrile safer.

By regulating the electric charge during the electrolytic reduction process, the present disclosure improves the current efficiency of electrolysis, reduces energy consumption of the electrolysis reaction, thereby reducing production costs.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments of the present disclosure are now described in detail. This detailed description should not be construed as limiting the present disclosure, but rather as providing a more comprehensive explanation of certain aspects, features, and embodiments of the present disclosure.

It should be understood that the terminology used herein is to describe particular embodiments only and is not intended to limit the scope of the present disclosure. Furthermore, concerning any numerical ranges recited herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within a stated range, as well as any smaller range formed by such intermediate values or between any other stated values or intermediate values within the stated range, is also encompassed by the present disclosure. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this present disclosure belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described may be used in the practice or testing of the present disclosure. All publications cited herein are incorporated by reference to disclose and describe the methods and/or materials related to such publications. In case of any conflict with the incorporated publications, the content of this specification shall prevail.

Various modifications and variations of the specific embodiments described herein may be made without departing from the scope or spirit of the present disclosure, as will be apparent to one of ordinary skill in the art. Other embodiments derived from the specification of the present disclosure will also be apparent to one of ordinary skill in the art. The specification and embodiments provided herein are to be regarded as illustrative only.

For the terms “comprising,” “including,” “having,” “containing,” and the like used herein, they are to be construed as open-ended terms, meaning “including but not limited to.”

The electrolytic reduction reaction of the present disclosure is carried out in an electrolytic cell. The dimensions of the cathode and anode in the electrolytic cell are both 60 millimeters (mm)×266 mm×26 mm. The anode and cathode are arranged parallel to each other, and the electrolyte solution is pumped in a circulating manner. A condensing recovery device is connected above the storage tank, with a condensing temperature of 5 degrees Celsius (° C.), to reflux evaporated acrylonitrile gas. The condensing device is connected to a gas chromatograph via a gas line to detect the oxygen content in the gas produced during the reaction. During the reaction, the cell voltage and instantaneous oxygen content are measured every time the electric charge increases by 0.1 Faraday per mol (F/mol). After the reaction is completed, gas chromatography is used to quantitatively analyze acrylonitrile, adiponitrile, and hexanetricarbonitrile, and the yields of adiponitrile and hexanetricarbonitrile, as well as the total current efficiency, are calculated.

Embodiment 1

A method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile is as follows:

200 grams (g) of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of ethylene diamine tetraacetic acid (EDTA) sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 milliliters (mL) of deionized water, and the potential of Hydrogen (pH) value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 liters per hour (L/h), and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 meters per second (m/s). The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 amperes per square meter (A/m²). After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile and 16 g of methanol (0.33 mol/L) are added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 1). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 54.99%, the yield of hexanetricarbonitrile is 19.66%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 97.75%.

TABLE 1
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.31	4.31	4.33	4.35	4.36	4.54	4.65	4.88
(V)
Oxygen content		0	0	0	0	29	54	83
(%)

Embodiment 2

A method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile is as follows:

200 g of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of EDTA sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 mL of deionized water, and the pH value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 L/h, and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 m/s. The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 A/m². After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile and 32 g of methanol (0.66 mol/L) are added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 2). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 54.89%, the yield of hexanetricarbonitrile is 20.94%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 98.82%.

TABLE 2
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.30	4.31	4.32	4.34	4.35	4.35	4.36	4.35
(V)
Oxygen content		0	0	0	0	0	0	0
(%)

Embodiment 3

A method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile is as follows:

200 g of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of EDTA sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 mL of deionized water, and the pH value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 L/h, and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 m/s. The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 A/m². After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile and 46 g of methanol (0.66 mol/L) are added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 3). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 54.10%, the yield of hexanetricarbonitrile is 21.22%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 97.96%.

TABLE 3
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.34	4.35	4.35	4.37	4.38	4.38	4.40	4.40
(V)
Oxygen content		0	0	0	0	0	0	0
(%)

Embodiment 4

A method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile is as follows:

200 g of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of EDTA sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 mL of deionized water, and the pH value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 L/h, and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 m/s. The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 A/m². After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile and 31 g of methanol (0.33 mol/L) are added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 4). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 54.88%, the yield of hexanetricarbonitrile is 19.66%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 97.03%.

TABLE 4
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.29	4.30	4.31	4.32	4.34	4.35	4.35	4.34
(V)
Oxygen content		0	0	0	0	0	0	0
(%)

Embodiment 5

A method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile is as follows:

200 g of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of EDTA sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 mL of deionized water, and the pH value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 L/h, and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 m/s. The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 A/m². After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile and 120 g of methanol (0.88 mol/L) are added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 5). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 54.21%, the yield of hexanetricarbonitrile is 19.77%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 96.81%.

TABLE 5
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.40	4.41	4.41	4.42	4.44	4.45	4.46	4.45
(V)
Oxygen content		0	0	0	0	0	0	0
(%)

Embodiment 6

A method for electrolytic reduction of acrylonitrile to produce adiponitrile and hexanetricarbonitrile is as follows:

200 g of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of EDTA sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 mL of deionized water, and the pH value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 L/h, and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 m/s. The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 A/m². After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile and 46 g of methanol (0.33 mol/L) are added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 6). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 55.03%, the yield of hexanetricarbonitrile is 19.81%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 97.94%.

TABLE 6
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.33	4.33	4.34	4.34	4.35	4.37	4.37	4.38
(V)
Oxygen content		0	0	0	0	0	0	0
(%)

Comparative example 1

200 g of dipotassium hydrogen phosphate, 40 g of borax, and 10 g of EDTA sodium salt are weighed, then 30 g of tetrabutylammonium hydroxide is weighed, the mixture is added to 1520 mL of deionized water, and the pH value of the solution is adjusted to 8 after stirring to dissolving; the solution is poured into a circulating single-compartment electrolytic cell, using a lead plate as the cathode and a 304 stainless steel plate as the anode, with a distance of 3 mm between the cathode and anode plates. The pump flow rate is 52.5 L/h, and the linear velocity of the electrolyte solution in the electrolytic cell is 0.081 m/s. The stirring and constant-temperature water bath device of the pump is started, the reaction temperature is set to 35° C., and the electrolytic current density is set to 1750 A/m². After the temperature of the reaction solution reaches the set temperature, 200 g of acrylonitrile is added, the power supply is turned on, and the electrolytic reduction reaction is performed. The initial cell voltage is recorded, and the instantaneous oxygen content is measured every time the electric charge increases by 0.1 F/mol (data shown in Table 7). When the electric charge reaches 0.7 F/mol, the electrolytic reaction is terminated. The results show that the yield of adiponitrile is 55.21%, the yield of hexanetricarbonitrile is 20.52%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 98.88%.

TABLE 7
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	4.70	4.71	4.72	4.74	4.81	4.84	4.96	5.05
(V)
Oxygen content		92	93	93	95	94	95	97
(%)

From Embodiment 1-Embodiment 6, it may be observed that under conditions of low linear velocity and a certain electric charge, the overall current efficiency of the electrolytic reaction is high, and the yields of adiponitrile and 1,3,6-hexanetricarbonitrile are high, with high added value. With the addition of easily oxidizable substances such as methanol, the cell voltage during the reaction decreases overall, suppressing oxygen evolution reactions. Moreover, the yields and current efficiency remain largely unchanged, indicating that the addition of easily oxidizable substances such as methanol reduces the cell voltage, inhibits anode oxygen evolution reactions, lowers energy consumption, eliminates explosion hazards, and improves the safety of diaphragm-free electrolysis, demonstrating excellent application value.

Comparative Example 2

Same as Embodiment 2, differing only in that the electric charge is 0.9 F/mol.

The yield of adiponitrile is 58.71%, the yield of hexanetricarbonitrile is 21.21%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 72.06%.

TABLE 8
Oxygen content during electrolysis

Electric charge (F/mol)	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9

Cell voltage (V)	4.30	4.31	4.32	4.34	4.35	4.35	4.36	4.35	4.37	4.59
Oxygen content (%)		0	0	0	0	0	0	0	0	25

Comparative Example 3

Same as Embodiment 2, differing only in that the distance between the cathode and anode plates is 6 mm.

The yield of adiponitrile is 35.61%, the yield of hexanetricarbonitrile is 7.23%, and the total current efficiency for adiponitrile and hexanetricarbonitrile is 51.74%.

TABLE 9
Oxygen content during electrolysis

Electric charge (F/mol)

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7

Cell voltage	5.41	5.43	5.44	5.44	5.45	5.46	5.47	5.47
(V)
Oxygen content		0	0	0	0	0	0	0
(%)

The above-mentioned embodiments only describe the preferred mode of the present disclosure, and do not limit the scope of the present disclosure. Under the premise of not departing from the design spirit of the present disclosure, various modifications and improvements made by one of ordinary skill in the art to the technical solution of the present disclosure should fall within the protection scope defined by the claims of the present disclosure.