Hydrogen oxidation reaction coupled succinic acid electrolytic synthesis method
By using hydrogen oxidation reaction as anode reaction, the reduction reaction of maleic acid is a cathode reaction, and using a gas diffusion electrode or a membrane electrode as anode, the high cost and high energy consumption problems caused by lead and iridium oxide anode in the prior art are solved, and the effect of reducing energy consumption and improving succinic acid yield is achieved.
Patent Information
- Application Number
- CN202410074869.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-18
- Publication Date
- 2025-07-18
AI Technical Summary
In the existing succinic acid electrolytic synthesis methods, the use of lead anode and iridium oxide anode leads to problems of high costs, short life and high energy consumption, and the price of iridium oxide anode fluctuates greatly, bringing cost pressure to enterprises.
The hydrogen oxidation reaction is used as the anode reaction, and the reduction reaction of maleic acid is a cathode reaction. A gas diffusion electrode or membrane electrode is used as the anode. A lead and iridium oxide anode are avoided, and an aqueous solution containing sulfuric acid is used as the electrolyte to synthesize succinic acid.
It significantly reduces the electrolytic voltage, reduces energy consumption, improves the yield of succinic acid, and reduces production costs.
Smart Images
Figure BDA0004671111340000021 
Figure BDA0004671111340000051 
Figure HDA0004671111350000011
Abstract
Description
(1) Technical Field
[0001] The present invention relates to a method for electroreductive synthesis of succinic acid, belonging to the field of electrolytic synthesis. Specifically, it relates to a method for electroreductive synthesis of succinic acid with the oxidation reaction of hydrogen as the anodic reaction and the reduction reaction of maleic acid as the cathodic reaction. (2) Background Art
[0002] The electroreduction method of maleic acid is currently the main method for industrial synthesis of succinic acid, with advantages such as safety and high efficiency. In the early stage, this method used a lead electrode as the anode (the oxidation of water to oxygen was the anodic reaction). The lead anode had the advantages of low cost and convenient processing, but had problems such as a short service life (3 - 12 months), generation of a large amount of highly polluting lead mud, and high energy consumption.
[0003] To overcome these problems of the lead anode, electrolytic synthesis succinic acid enterprises have started to use iridium oxide anodes to replace lead anodes for more than a decade. As is well known, the iridium oxide anode (usually a titanium - coated iridium oxide electrode) is the best oxygen - evolving anode, with not only a very low oxygen - evolution over - potential but also very stable performance. The service life of the iridium oxide anode is basically proportional to the iridium content on the electrode. The iridium oxide electrode with an iridium content of 10 g / m² can have a service life of about 2 years at a current density of 1000 A / m 2 Therefore, the loss of the iridium oxide anode is one of the main costs in the industrial electrolytic synthesis of succinic acid using this electrode. At the beginning of 2021, the price of metallic iridium increased from 400 yuan / g to 1500 yuan / g and has been running at a high level since then. This has brought great cost pressure to enterprises using iridium oxide anodes for electrolytic synthesis of succinic acid.
[0004] Therefore, there is an urgent need to develop a method for electrolytic synthesis of succinic acid that does not use lead anodes and iridium oxide anodes to replace the existing methods. (3) Summary of the Invention
[0005] The purpose of the present invention is to provide a method for electrolytic synthesis of succinic acid coupled with the oxidation reaction of hydrogen. The method uses the oxidation reaction of hydrogen as the anodic reaction and the reduction reaction of maleic acid as the cathodic reaction, which can not only avoid the use of lead electrodes and iridium oxide anodes, but also greatly reduce the electrolysis voltage, and thus greatly reduce the energy consumption. In addition, this method can also significantly improve the yield of succinic acid.
[0006] The technical solution adopted by the present invention is as follows:
[0007] The present invention provides a method for electrolytic synthesis of succinic acid coupled with the oxidation reaction of hydrogen. The method uses the oxidation reaction of hydrogen as the anodic reaction, the reduction reaction of maleic acid (B) as the cathodic reaction, and an aqueous solution containing sulfuric acid as the electrolyte for electrolysis, and recovers the electrolysis product to obtain the succinic acid (A).
[0008]
[0009] Further, the anodic reaction occurs on the gas diffusion electrode or the membrane electrode.
[0010] Further, the gas diffusion electrode is composed of a gas diffusion layer and a catalytic layer. The gas diffusion layer is a porous carbon material or a metal material. The carbon material is carbon paper, carbon cloth, graphite felt, carbon felt or carbon foam. The metal material is titanium or silver. The catalytic layer is composed of a platinum-carbon or palladium-carbon catalyst and a binder. The binder is polytetrafluoroethylene resin or Nafion resin or a mixture of both.
[0011] Further, the Pt or Pd loading in the gas diffusion electrode is 0.1 - 0.5 mg / cm 2 .
[0012] Further, the membrane electrode is composed of a gas diffusion layer, a catalytic layer and a cation exchange membrane. The catalytic layer is located between the gas diffusion layer and the cation exchange membrane. The gas diffusion layer is a porous carbon material or a metal material. The carbon material is carbon paper, carbon cloth, graphite felt, carbon felt or carbon foam. The metal material is titanium or silver. The catalytic layer is composed of a platinum-carbon or palladium-carbon catalyst and a binder. The binder is polytetrafluoroethylene resin or Nafion resin or a mixture of both. The cation exchange membrane is a sulfonic acid type cation exchange membrane.
[0013] Further, the Pt or Pd loading in the membrane electrode is 0.1 - 0.5 mg / cm 2 .
[0014] Further, when the anodic reaction occurs on the membrane electrode, a diaphragm ( Figure 1 in A) electrolysis method is adopted.
[0015] Further, when the anodic reaction occurs on the gas diffusion electrode, a diaphragm ( Figure 1 in B) or a non-diaphragm ( Figure 1 in C) electrolysis method is adopted, and the non-diaphragm electrolysis method is preferred.
[0016] Further, the diaphragm used in the diaphragm electrolysis method is a cation exchange membrane or a microporous membrane. The electrolysis device of the diaphragm electrolysis method is divided into a gas chamber, an anode chamber, and a cathode chamber in sequence by an anode and a diaphragm. The gas chamber is used to introduce hydrogen. An anode is arranged between the gas chamber and the anode chamber, a diaphragm is arranged between the anode chamber and the cathode chamber, a cathode is arranged inside the cathode chamber, and the cathode is made of a titanium sheet; the diaphragm is preferably a Nafion-324 membrane; the anode chamber uses an aqueous solution containing 0.1-1.0 mol / L (preferably 0.5 mol / L) sulfuric acid as the anolyte; the cathode chamber uses an aqueous solution containing 0.5-2 mol / L (preferably 1 mol / L) maleic acid + 0.1-1.0 mol / L (preferably 0.5 mol / L) sulfuric acid as the catholyte; electrolysis is carried out at 10-70 °C and a cathode current density of 5-20 A / dm 2 , and an anode current density of 10-38 A / dm 2 under the conditions (preferably 50 °C, a cathode current density of 10 A / dm 2 , and an anode current density of 19 A / dm 2 ).
[0017] Further, the electrolysis device of the diaphragm-free electrolysis method is divided into a gas chamber and an electrolysis chamber by an anode. An anode is arranged between the gas chamber and the electrolysis chamber, and a cathode is arranged inside the electrolysis chamber. The cathode is made of a titanium sheet; the gas chamber is used to introduce hydrogen; the electrolysis chamber uses an aqueous solution containing 0.5-2 mol / L (preferably 1 mol / L) maleic acid + 0.1-1.0 mol / L (preferably 0.5 mol / L) sulfuric acid as the electrolyte; electrolysis is carried out at 10-70 °C and a cathode current density of 5-20 A / dm 2 , and an anode current density of 10-38 A / dm 2 under the conditions (preferably 50 °C, a cathode current density of 10 A / dm 2 , and an anode current density of 19 A / dm 2 ).
[0018] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in: (1) In the method for electrolytic synthesis of succinic acid coupling with hydrogen oxidation reaction of the present invention, the hydrogen oxidation reaction is used as the anodic reaction, and preferably a membrane electrode or a gas diffusion electrode is used as the anode, without using an iridium oxide anode and a lead anode, effectively reducing the cost; (2) The electrolysis voltage of the method of the present invention drops by about 1.5 V (compared with the iridium oxide anode), significantly reducing the energy consumption. (3) The yield of succinic acid in the method of the present invention can be increased by about 5-10%. (IV) BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1, Schematic diagram of electrolytic synthesis of succinic acid with hydrogen oxidation reaction as the anodic reaction; O represents maleic acid, R represents succinic acid; A represents the membrane electrode diaphragm electrolysis method, B represents the gas diffusion electrode diaphragm electrolysis method, and C represents the gas diffusion electrode diaphragm-free electrolysis method.
[0020] Figure 2 , Electrolytic reduction device diagram with hydrogen oxidation reaction as the anodic reaction; A represents the diaphragm electrolysis device, and B represents the diaphragm-free electrolysis device. (V) Specific implementation modes
[0021] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:
[0022] In the following examples and comparative examples, the gas diffusion electrode (Pt loading is 0.3 - 0.5 mg / cm 2 ), the gas diffusion electrode (Pd loading is 0.3 mg / cm 2 ), the membrane electrode (Pt loading is 0.3 - 0.5 mg / cm 2 ), the titanium-plated iridium oxide electrode (iridium content is 1 mg / cm 2 ) and the lead electrode (lead content 99.9%) are all purchased from Hangzhou Sai'ao Electrochemical Instrument Co., Ltd.
[0023] The membrane electrode is composed of a gas diffusion layer, a catalytic layer and a cationic membrane, and the catalytic layer is located between the gas diffusion layer and the cationic membrane. Among them, the carbon cloth is the gas diffusion layer, the catalytic layer is composed of a platinum-carbon catalyst and Nafion resin, and the cationic membrane is a Nafion-117 membrane.
[0024] The gas diffusion electrode is composed of a gas diffusion layer and a catalytic layer. Among them, the carbon paper is the gas diffusion layer, and the catalytic layer is composed of a platinum-carbon catalyst, Nafion resin and polytetrafluoroethylene resin.
[0025] Example 1. Membrane electrode - diaphragm electrolysis
[0026] Using Figure 2 The diaphragm electrolytic cell with the structure shown in A, the diaphragm electrolytic cell is sequentially separated into a gas chamber, an anodic chamber and a cathodic chamber by an anode and a diaphragm. An anode is arranged between the gas chamber and the anodic chamber, and a diaphragm is arranged between the anodic chamber and the cathodic chamber. The gas chamber is used to introduce hydrogen, and a cathode is arranged in the cathodic chamber. The membrane electrode is the anode (area: 3.14 cm 2 , Pt loading is 0.5 mg / cm 2 ), the titanium sheet is the cathode (area: 6 cm 2 ), and the Nafion-324 membrane is used as the diaphragm.
[0027] Using an aqueous solution containing 0.5 mol / L sulfuric acid as the anolyte (80 mL), and an aqueous solution containing 1 mol / L maleic acid + 0.5 mol / L sulfuric acid as the catholyte (60 mL); during the electrolysis process, the flow rate of hydrogen gas was controlled at 20 mL / min. The temperatures of the catholyte and anolyte were controlled at 50 °C, and an electrolysis was carried out by applying a current of 600 mA (the cathode current density was: 10 A / dm 2 , and the anode current density was: 19.1 A / dm 2 ). After 6 hours of electrolysis, the electrolysis was stopped. The yield of succinic acid in the catholyte was 94.5%, and the average voltage was 4.6 V (the initial voltage was 4.3 V, and the voltage at the end of electrolysis was 4.9 V).
[0028] Example 2: Gas diffusion electrode - diaphragm electrolysis
[0029] Using the diaphragm electrolytic cell with the structure shown as A in Example 1 (the same as in Example 1), using an aqueous solution containing 0.5 mol / L sulfuric acid as the anolyte (80 mL), and an aqueous solution containing 1 mol / L maleic acid + 0.5 mol / L sulfuric acid as the catholyte (60 mL); the gas diffusion electrode was used as the anode (area: 3.14 cm Figure 2 , the Pt loading was 0.3 mg / cm 2 , 2 ), the titanium sheet was used as the cathode (area: 6 cm 2 ), and the Nafion-324 membrane was used as the diaphragm. During the electrolysis process, the flow rate of hydrogen gas was controlled at 20 mL / min. The temperatures of the catholyte and anolyte were controlled at 50 °C, and an electrolysis was carried out by applying a current of 600 mA (the cathode current density was: 10 A / dm 2 , and the anode current density was: 19.1 A / dm 2 ). After 6 hours of electrolysis, the electrolysis was stopped. The yield of succinic acid in the catholyte was 94.8%, and the average voltage was 4.1 V (the initial voltage was 3.8 V, and the voltage at the end of electrolysis was 4.4 V).
[0030] Example 3: Gas diffusion electrode - diaphragmless electrolysis
[0031] Using Figure 2 the diaphragmless electrolytic cell with the structure shown as B, the diaphragmless electrolytic cell is separated into a gas chamber and an electrolysis chamber by the anode, an anode is arranged between the gas chamber and the electrolysis chamber, a cathode is arranged in the electrolysis chamber, and the gas chamber is used for introducing hydrogen gas. The membrane electrode was used as the anode (area: 3.14 cm 2 , the Pt loading was 0.3 mg / cm 2 ), the titanium sheet was used as the cathode (area: 6 cm 2 ).
[0032] The electrolyte (60 mL) was an aqueous solution containing 1 mol / L maleic acid + 0.5 mol / L sulfuric acid. During the electrolysis process, the flow rate of hydrogen was controlled to 20 mL / min. The temperature of the electrolyte was controlled to 50°C, and a current of 600 mA was applied for electrolysis (cathode current density: 10 A / dm 2 , anode current density: 19.1A / dm 2 The electrolysis was stopped after 6 hours, and the yield of succinic acid in the electrolyte was 95.1%, and the average voltage was 3.1 V (the initial voltage was 2.8 V, and the voltage at the end of the electrolysis was 3.4 V).
[0033] Example 4-11: Effects of catalyst type and loading, electrolyte composition, current density, temperature, etc. on electrolytic reduction
[0034] The method of Example 1 was adopted, and the type and loading amount of membrane electrode catalyst, cathode liquid composition, current density, and temperature were changed. Other operations were the same. The experimental conditions and results are shown in Table 1.
[0035] Table 1 Effects of catalyst type, electrolyte composition, current density, temperature, etc. on electrolytic reduction a
[0036]
[0037] Remark: a Other unspecified conditions are consistent with those in Example 1; S indicates that the conditions are consistent with those in Example 1.
[0038] Comparative Example 1: Membrane Electrode-Diaphragm-Free Electrolysis
[0039] use Figure 2 The membrane-free electrolytic cell with the structure shown in B is an electrolyte (60 mL) containing 1 mol / L maleic acid + 0.5 mol / L sulfuric acid; the membrane electrode is the anode (area: 3.14 cm 2 , Pt loading is 0.5 mg / cm 2 ), titanium sheet is cathode (area: 6cm 2 During the electrolysis process, the flow rate of hydrogen was controlled at 20 mL / min. The temperature of the electrolyte was controlled at 50°C, and a current of 600 mA was applied for electrolysis (cathode current density: 10 A / dm 2 , anode current density: 19.1A / dm 2 ). After 2 hours of electrolysis, the electrolysis voltage increased from the initial 3.2V to 11.8V, and the electrolysis was stopped.
[0040] Compared with Example 1, the electrolysis voltage rises rapidly during the electrolysis process.
[0041] Comparative Example 2: Iridium Oxide Anode - Electrolysis without Diaphragm
[0042] Adopt Figure 2 The diaphragm-free electrolytic cell with the structure shown in B. Use an aqueous solution containing 1 mol / L maleic acid + 0.5 mol / L sulfuric acid as the electrolyte (60 mL); the titanium-plated iridium oxide electrode is used as the anode (area: 3.14 cm 2 ), and the titanium sheet is used as the cathode (area: 6 cm 2 ). During the electrolysis process, the flow rate of hydrogen is controlled at 20 mL / min. The temperature of the electrolyte is controlled at 50 °C, and a current of 600 mA is applied for electrolysis (the cathode current density is: 10 A / dm 2 , and the anode current density is: 19.1 A / dm 2 ). After 6 hours of electrolysis, the electrolysis is stopped. The yield of succinic acid in the electrolyte is 89.9%, and the average voltage is 3.1 + 1.5 V (the initial voltage is 2.8 + 1.5 V, and the voltage at the end of electrolysis is 3.4 + 1.5 V).
[0043] Compared with Example 3, the amount of precious metal used on the anode increases to 2 times, and the price increases to about 8 times; the yield of succinic acid decreases by about 5%, and the electrolysis voltage increases by 1.5 V.
[0044] Comparative Example 3, lead anode - diaphragm-free electrolysis
[0045] Adopt Figure 2 The diaphragm-free electrolytic cell with the structure shown in B. Use an aqueous solution containing 1 mol / L maleic acid + 0.5 mol / L sulfuric acid as the electrolyte (60 mL); the lead electrode is used as the anode (area: 3.14 cm 2 , thickness: 2 mm), and the titanium sheet is used as the cathode (area: 6 cm 2 ). During the electrolysis process, the flow rate of hydrogen is controlled at 20 mL / min. The temperature of the electrolyte is controlled at 50 °C, and a current of 600 mA is applied for electrolysis (the cathode current density is: 10 A / dm 2 , and the anode current density is: 19.1 A / dm 2 ). After 6 hours of electrolysis, the electrolysis is stopped. The thickness of the lead electrode is reduced to about 1.4 mm. The yield of succinic acid in the electrolyte is 84.5%, and the average voltage is 3.1 + 2.3 V (the initial voltage is 2.8 + 2.3 V, and the voltage at the end of electrolysis is 3.4 + 2.3 V).
[0046] Compared with Example 3, the yield of succinic acid decreases by about 10%, the electrolysis voltage increases by 2.3 V, and a lot of lead mud is also produced.
Claims
1. A method for electro-synthesizing succinic acid by coupling with hydrogen oxidation reaction, characterized in that, The described method uses the oxidation reaction of hydrogen as the anodic reaction, the reduction reaction of maleic acid as the cathodic reaction, and an aqueous solution containing sulfuric acid as the electrolyte for electrolysis, and recovers the electrolysis products to obtain the described succinic acid.
2. The method according to claim 1, wherein The described anodic reaction occurs on a gas diffusion electrode or a membrane electrode.
3. The method according to claim 2, wherein The described gas diffusion electrode is composed of a gas diffusion layer and a catalytic layer. The gas diffusion layer is a porous carbon material or a metal material. The carbon material is carbon paper, carbon cloth, graphite felt, carbon felt or carbon foam, and the metal material is titanium or silver. The catalytic layer is composed of a platinum-carbon or palladium-carbon catalyst and a binder. The binder is polytetrafluoroethylene resin or Nafion resin or a mixture of both.
4. The method according to claim 3, wherein The platinum or palladium loading in the gas diffusion electrode is 0.1 to 0.5 mg / cm 2 .
5. The method according to claim 2, wherein The described membrane electrode is composed of a gas diffusion layer, a catalytic layer and a cation exchange membrane. The catalytic layer is located between the gas diffusion layer and the cation exchange membrane. The gas diffusion layer is a porous carbon material or a metal material. The carbon material is carbon paper, carbon cloth, graphite felt, carbon felt or carbon foam, and the metal material is titanium or silver. The catalytic layer is composed of a platinum-carbon or palladium-carbon catalyst and a binder. The binder is polytetrafluoroethylene resin or Nafion resin or a mixture of both. The cation exchange membrane is a sulfonic acid type cation exchange membrane.
6. The method according to claim 5, wherein The platinum or palladium loading in the membrane electrode is 0.1 to 0.5 mg / cm 2 .
7. The method according to claim 2, wherein When the described anodic reaction occurs on a membrane electrode, a diaphragm electrolysis method is adopted.
8. The method according to claim 2, wherein When the described anodic reaction occurs on a gas diffusion electrode, a diaphragm or non-diaphragm electrolysis method is adopted.
9. The method according to claim 7 or 8, characterized in that, The diaphragm used in the diaphragm electrolysis method is a cation exchange membrane or a microporous membrane; the electrolysis device of the diaphragm electrolysis method is divided into a gas chamber, an anode chamber and a cathode chamber by an anode and a diaphragm in sequence. A cathode is arranged inside the cathode chamber, and the gas chamber is used for introducing hydrogen; the cathode is made of titanium sheet; the diaphragm is a Nafion-324 membrane; the anode chamber uses an aqueous solution containing 0.1-1.0 mol / L sulfuric acid as the anolyte; the cathode chamber uses an aqueous solution containing 0.5-2 mol / L maleic acid + 0.1-1.0 mol / L sulfuric acid as the catholyte; electrolysis is carried out at 10-70 °C and a cathode current density of 5-20 A / dm 2 , and an anode current density of 10-38 A / dm 2 under the conditions.
10. The method according to claim 8, characterized in that, The electrolysis device of the diaphragm-free electrolysis method is separated into a gas chamber and an electrolysis chamber by an anode. A cathode is arranged inside the electrolysis chamber, and the cathode is made of a titanium sheet. Hydrogen is introduced into the gas chamber, and an aqueous solution containing 0.5 - 2 mol / L maleic acid + 0.1 - 1.0 mol / L sulfuric acid is used as the electrolyte in the cathode chamber; electrolysis is carried out under the conditions of 10 - 70 °C, a cathode current density of 5 - 20 A / dm 2 , and an anode current density of 10 - 38 A / dm 2 .