System for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide
Through the continuous system of electrocatalytic synthesis of hydrogen peroxide, the concentration is achieved using a falling film evaporator and a distillation tower, which solves the problem of cumbersome purification steps and high energy consumption in the olefin epoxidation reaction, and achieves efficient and green hydrogen peroxide purification and In situ synthesis of olefin epoxidation reaction.
Patent Information
- Application Number
- CN202310964147.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-02
- Publication Date
- 2025-02-14
AI Technical Summary
In the prior art, the purification steps of high-concentration hydrogen peroxide in the olefin epoxidation reaction are cumbersome, the energy consumption is high, and there are economic and safety problems in transportation of high-concentration hydrogen peroxide.
Through a continuous system for electrocatalytic synthesis of hydrogen peroxide, the low concentration of electrocatalytic synthesis of hydrogen peroxide is concentrated through a falling film evaporator and a distillation tower, and then concentrated to 50-60%, and then directly used for olefin epoxidation reaction.
The efficient purification of hydrogen peroxide and the in-situ synthesis of olefin epoxidation reactions are achieved, which avoids high energy consumption, transportation safety and economic problems in traditional processes, and at the same time improves the selectivity and production efficiency of epoxy compounds.
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Figure CN119433566A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of petrochemical industry, and specifically relates to a process and a device for producing epoxy compounds by electrocatalytic synthesis of hydrogen peroxide coupled with olefin epoxidation reaction. Background Art
[0002] Olefin epoxidation is one of the main methods for producing epoxy compounds. Epoxides are widely used in the chemical and pharmaceutical fields. For example, propylene oxide is an important organic synthesis intermediate that can be used to prepare surfactants, resins, coatings, etc. Epoxides such as ethylene oxide and butylene oxide are also commonly used chemical raw materials.
[0003] The methods for producing epoxides in traditional industries mainly include the chlorohydrin method, the co-oxidation method and the direct oxidation method with hydrogen peroxide. Among them, although the chlorohydrin method is mature in technology, the equipment is severely corroded, a large amount of wastewater and waste residue will be produced, and the pollution to the environment is very serious. The co-oxidation method requires large investment, and the amount of co-products produced is large, and the price is restricted by the market. The direct oxidation method with hydrogen peroxide has gradually become the main direction of epoxide compound production due to its green process, small investment, and the recycling of catalysts and solvents. It has become more mature and shows good industrialization prospects. However, the direct oxidation method with hydrogen peroxide currently uses high-concentration hydrogen peroxide, which is mainly produced by the anthraquinone method. The anthraquinone process uses organic solvents, and hydrogen peroxide needs to go through extraction, concentration, purification and other steps to obtain 27.5% hydrogen peroxide. The process is complex, costly and not green. The purchase price of hydrogen peroxide is also restricted by the market, the transportation cost is high, and there is a risk of explosion during transportation. The electrocatalytic synthesis of hydrogen peroxide has the problem of low product concentration. If it is used for olefin epoxidation reaction after concentration, it will require a very high cost, and the production energy consumption is high and the process is not green.
[0004] US Patent USP6555493 discloses a method for synthesizing epoxy compounds in one step using propylene, oxygen and hydrogen as raw materials through a precious metal-loaded TS-1 catalyst. In this method, propylene reacts with hydrogen to form propane, and this side reaction reduces the yield of epoxy compounds. Chinese Patent CN107216296 discloses a method for preparing epoxy compounds in a microchannel reactor, in which propylene contacts hydrogen peroxide synthesized in situ by hydrogen and oxygen in the gas phase in the microchannel reactor, and epoxy compounds are directly generated under the action of a catalyst. The reactor scale of this method is small, the propylene conversion rate and the yield of epoxy compounds are low, and there is still a large gap from industrial production. Summary of the invention
[0005] The purpose of the present invention is mainly to address the deficiencies of the above-mentioned prior art, and to provide a process for the continuous electrocatalytic synthesis of hydrogen peroxide coupled with the production of olefin epoxy compounds by concentrating the electrocatalytically synthesized hydrogen peroxide through a simple concentration step. The process overcomes the problems of complicated purification steps and high energy consumption of the source of high-concentration hydrogen peroxide in the current olefin epoxidation reaction, avoids the economic and safety problems caused by the transportation of high-concentration hydrogen peroxide, and realizes a green process integrating hydrogen peroxide synthesis and olefin epoxidation reaction.
[0006] The technical solution adopted by the present invention is as follows:
[0007] A system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide, the system comprising an electrocatalytic hydrogen peroxide synthesis unit, a hydrogen peroxide concentration device and a fixed bed reactor connected in sequence;
[0008] The electrocatalytic hydrogen peroxide synthesis unit is formed by connecting a plurality of reactors in parallel, wherein the reactor is composed of an anode reinforcement plate, a cathode reinforcement plate and a solid electrolyte chamber; the concentration device includes a falling film evaporator and a distillation tower.
[0009] In the technical solution of the present invention: an anode gas diffusion electrode is provided between the anode reinforcement plate and the solid electrolyte chamber, and a cathode gas diffusion electrode is provided between the anode gas diffusion electrode and the solid electrolyte chamber.
[0010] In the technical solution of the present invention: the top of the distillation tower is connected to the upper part of the falling film evaporator through a steam jet pump.
[0011] In the technical solution of the present invention: the top of the electrocatalytic hydrogen peroxide synthesis unit is connected to the falling film evaporator, the bottom of the falling film evaporator is connected to the top of the electrocatalytic hydrogen peroxide synthesis unit, and the output end of the lower part of the falling film evaporator is connected to the distillation tower.
[0012] In the technical solution of the present invention: the output end at the bottom of the distillation tower is connected to the fixed bed reactor.
[0013] The system of the invention realizes highly selective integrated synthesis of epoxy compounds by directly coupling olefin epoxidation reaction after concentrating hydrogen peroxide through a hydrogen peroxide concentration process.
[0014] In the technical solution of the present invention: the anode and cathode reinforcement plates are made of corrosion-resistant metal conductor materials, the solid electrolyte chamber is made of polymer insulating materials, and there are hollow groove flow channels on the inner sides of the anode and cathode reinforcement plates and in the middle of the solid electrolyte chamber.
[0015] In the technical solution of the present invention, electrocatalytic technology is used to synthesize hydrogen peroxide, the anode catalyst is platinum carbon, the cathode catalyst is special modified carbon, the solid electrolyte is a cation exchange resin, and the solvent is water, so that the production process and the subsequent product purification process are more green. Hydrogen peroxide with a concentration of 2 to 20% can be produced.
[0016] In the technical solution of the present invention: the hydrogen peroxide used in the olefin epoxidation reaction is generated in situ by an electrocatalytic device and is directly used to synthesize epoxy compounds after being concentrated.
[0017] In the technical scheme of the present invention, 2-20% hydrogen peroxide produced by electrocatalysis is used as raw material to enter the atmospheric pressure falling film evaporator, the lower part of the falling film evaporator is connected to the distillation tower, and the hydrogen peroxide at the bottom of the falling film evaporator is circulated to the top of the distillation tower through a pump. The steam temperature in the falling film evaporator is 75-80°C, and the operating temperature of the distillation tower is 40-50°C, which can produce hydrogen peroxide with a concentration of 50-70%.
[0018] In the technical solution of the present invention: the steam outlet at the top of the distillation tower is connected to a steam jet pump and is utilized as waste heat, thereby reducing the energy consumption of the system.
[0019] In the technical scheme of the present invention, the reactor for olefin epoxidation reaction is a fixed bed reactor, methanol and water are solvents, a 25-30% hydrogen peroxide aqueous solution is an oxidant, and a titanium silicon molecular sieve is a catalyst. Ethylene, propylene, etc. are oxidized into ethylene oxide and propylene oxide by direct oxidation.
[0020] In the technical scheme of the present invention, the discharge end of the hydrogen peroxide synthesis device increases the concentration of hydrogen peroxide to 50-60% through a concentrator, and then is connected to the feed end of a fixed bed epoxy compound synthesis device to provide high-concentration hydrogen peroxide for the synthesis of epoxy compounds.
[0021] In this device, the electrocatalytic hydrogen peroxide synthesis device and the fixed bed synthesis cyclized product device are connected in series, so that the high-concentration hydrogen peroxide synthesized by electrocatalysis can be directly used for the synthesis of epoxy compounds, which greatly improves the reaction efficiency and safety. The hydrogen peroxide synthesis device is composed of an anode reinforcement plate, an anode gas diffusion electrode, a solid electrolyte chamber, a cathode gas diffusion electrode, and a cathode reinforcement plate. The tops of the anode and cathode reinforcement plates are gold-plated and connected to the positive and negative electrodes of the electrochemical workstation respectively through wires. Hydrogen and oxygen enter from the air inlets on the outer walls of the cathode reinforcement plate and the anode reinforcement plate respectively, and water enters from the side of the solid electrolyte chamber through a constant current injection pump, carrying the synthesized hydrogen peroxide out from the side, realizing the continuous synthesis of hydrogen peroxide.
[0022] Furthermore, an air inlet and an air outlet are provided on the outer side walls of the anode reinforcement plate and the cathode reinforcement plate, and a liquid inlet and a liquid outlet are provided on the front and rear side walls of the solid electrolyte chamber, respectively. The anode and cathode reinforcement plates are both made of stainless steel material with gold-plated tops, and the inner walls have S-shaped grooves. The solid electrolyte chamber is a stainless steel plate with a hollow middle and an S-shaped groove, and the S-shaped groove is filled with solid electrolyte before the reaction.
[0023] Hydrogen enters the anode through the air inlet on the side wall of the anode reinforcement plate, reacts on the gas diffusion electrode loaded with the anode electrocatalyst, dissociates into hydrogen protons and enters the solid electrolyte chamber through the proton exchange membrane. Oxygen enters from the cathode air inlet, undergoes a two-electron oxygen reduction reaction on the gas diffusion electrode loaded with the electrocatalyst, forms superoxide ions, enters the solid electrolyte chamber through the anion exchange membrane, combines with hydrogen protons to form hydrogen peroxide, and carries the hydrogen peroxide out of the reactor through the flow of water.
[0024] Furthermore, 5-10% hydrogen peroxide synthesized by the electrocatalytic reactor enters from the top of the falling film evaporator, enters from the bottom of the falling film evaporator after heating, and 50-60% hydrogen peroxide extracted from the bottom of the distillation tower after concentration directly enters the rear end propylene epoxidation fixed bed device to participate in the synthesis of epoxy compounds together with olefins and methanol.
[0025] The beneficial effects of the present invention are as follows:
[0026] (1) In this device, an electrocatalytic hydrogen peroxide synthesis device and an epoxy compound synthesis device are used in series, and the low-concentration hydrogen peroxide synthesized by electrocatalysis is concentrated to 50-60% by a hydrogen peroxide concentration device, which can directly realize the in-situ synthesis of hydrogen peroxide and the back-end epoxy compound, avoiding the environmental and energy consumption problems caused by the purification and concentration of hydrogen peroxide containing organic solvents in the anthraquinone process, and also avoiding the safety and economic problems caused by the transportation of high-concentration hydrogen peroxide.
[0027] (2) The synthesis of hydrogen peroxide adopts an electrocatalytic process, with water as the only solvent. Solid electrolytes are used in the electrocatalytic hydrogen peroxide synthesis device, avoiding the addition of liquid electrolytes, making the process greener and also avoiding the subsequent product separation problem.
[0028] (3) In the hydrogen peroxide concentration device, the steam at the top of the distillation tower is used to heat the falling film evaporator, realizing the utilization of waste heat and reducing the energy consumption of the system.
[0029] (4) The device has a simple structure, green process, safe and convenient operation, and can achieve highly selective synthesis of epoxy compounds while saving equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a schematic diagram of the structure of the present invention.
[0031] In the figure, 1 is the electrocatalytic synthesis of hydrogen peroxide unit; 2 is the falling film evaporator; 3 is the distillation tower; 4 is the fixed bed reactor; 5 is the circulation pump; and 6 is the steam jet pump.
[0032] Figure 2 This is a detailed diagram of the electrocatalytic synthesis of hydrogen peroxide unit. In the figure, 7 is the anode reinforcement plate; 8 is the anode gas diffusion electrode; 9 is the solid electrolyte chamber; 10 is the cathode gas diffusion electrode; and 11 is the cathode reinforcement plate. DETAILED DESCRIPTION
[0033] The following is combined with Figure 1 and 2 The present invention will be further described:
[0034] like Figure 1 As shown, a system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide, the system comprises an electrocatalytic hydrogen peroxide synthesis unit, a hydrogen peroxide concentration device and a fixed bed reactor connected in sequence;
[0035] The electrocatalytic hydrogen peroxide synthesis unit is formed by connecting a plurality of reactors in parallel, and the reactor is composed of an anode reinforcement plate, a cathode reinforcement plate and a solid electrolyte chamber; the concentration device includes a falling film evaporator and a distillation tower. An anode gas diffusion electrode is provided between the anode reinforcement plate and the solid electrolyte chamber, and a cathode gas diffusion electrode is provided between the anode gas diffusion electrode and the solid electrolyte chamber. The top of the distillation tower is connected to the upper part of the falling film evaporator through a steam jet pump. The top of the electrocatalytic hydrogen peroxide synthesis unit is connected to the falling film evaporator, the bottom end of the falling film evaporator is connected to the top of the electrocatalytic hydrogen peroxide synthesis unit, and the output end of the lower part of the falling film evaporator is connected to the distillation tower. The output end at the bottom of the distillation tower is connected to the fixed bed reactor.
[0036] The outer walls of the anode and cathode reinforcement plates are provided with air inlets and outlets. There is a gold coating on the top to enhance conductivity. The top of the anode and cathode are connected to the positive and negative electrodes of the electrochemical workstation through wires. The specific steps for synthesizing hydrogen peroxide are as follows: hydrogen and oxygen enter the anode and cathode from the air inlets on the outer walls of the anode and cathode reinforcement plates, respectively. Electrochemical reactions are carried out on the anode and cathode gas diffusion electrodes. Hydrogen is ionized and enters the solid electrolyte chamber through the proton exchange membrane, and oxygen is oxidized to form superoxide ions, which enter the solid electrolyte chamber through the anion exchange membrane and combine with hydrogen protons to form hydrogen peroxide. The aqueous solution enters the system from the back side of the solid electrolyte chamber through an injection pump, carries the produced hydrogen peroxide out of the system from the front end of the solid electrolyte chamber, and enters the concentration device at the back end for concentration.
[0037] The low-concentration hydrogen peroxide synthesized by electrocatalysis enters the falling film evaporator 2 from the top through the pipeline 103. The hydrogen peroxide and the aqueous solution are heated by the hot steam input by the jet pump 7. The hydrogen peroxide with a concentration of 20-30% extracted from the lower part of the falling film evaporator 2 further enters the distillation tower 3 for distillation, and the bottom effluent is refluxed to the top of the falling film evaporator through the circulation pump for circulation evaporation. The steam at the top of the distillation tower 3 is input into the falling film evaporator through the steam jet pump 6 to provide a heat source, thereby realizing the utilization of waste heat. After distillation and concentration, the hydrogen peroxide with a concentration of 50-60% extracted from the bottom of the distillation tower is input into the fixed bed device at the rear end for the synthesis of epoxy compounds.
[0038] Example 1
[0039] like Figure 2 As shown, hydrogen and oxygen are introduced into the electrocatalytic hydrogen peroxide synthesis device from the anode air inlet and the cathode air inlet at a flow rate of 20 mL / min, with Pt / C coated on conductive carbon paper as the anode catalyst and carbon black after oxidation treatment as the cathode catalyst, and the catalyst loading is 20%; the solid electrolyte is a cation exchange resin, and the flow rate of the aqueous solution is 1 mL / min. A voltage of 3V is applied to both ends of the reactor through an electrochemical workstation. After stabilization for 1 hour, the concentration of hydrogen peroxide produced continuously is 10-20%.
[0040] The 10-20% hydrogen peroxide produced by electrocatalysis is input into the falling film evaporator 2 through pipeline 102, and the hydrogen peroxide and aqueous solution are heated to 75-80°C under the action of the hot steam input by the jet pump 7 through pipeline 106. The gas phase output of the falling film evaporator has a concentration of 20-30% hydrogen peroxide and enters the bottom of the distillation tower through pipeline 105. The liquid phase is output from the bottom of the falling film evaporator through pipeline 104 and enters the circulation pump 5. The liquid phase is output from the circulation pump through pipeline 103 and input into the falling film evaporator for circulation evaporation. The steam at the top of the distillation tower 3 enters the steam jet pump through pipeline 107 and is used as a heat source. The operating temperature of the distillation tower is 40-45°C, and the operating pressure is 0.1MPa. Hydrogen peroxide with a concentration of 50-60% is extracted from the bottom of the distillation tower 3, mixed with methanol input from pipeline 108 and pipeline 109, and then enters the reaction system from the top of the fixed bed reactor 4, and undergoes epoxidation reaction with ethylene gas entering from the bottom of the fixed bed reactor 4 through pipeline 110 under the action of titanium silicon molecular sieve catalyst to produce ethylene oxide. Among them, the reaction temperature is 60-55°C and the reaction pressure is 4MPa. The reaction liquid at the bottom of the reactor 4 is subsequently separated to obtain pure epoxide compounds. The concentration of hydrogen peroxide is calculated by iodine titration, and the selectivity of epoxide compounds in the product is calculated by chromatographic internal standard method. The results are shown in Table 1. .
[0041] Example 2
[0042] like Figure 2As shown, hydrogen and oxygen are introduced into the electrocatalytic hydrogen peroxide synthesis device from the anode air inlet and the cathode air inlet at a flow rate of 20 mL / min, with Pt / C coated on conductive carbon paper as the anode catalyst and carbon black after oxidation treatment as the cathode catalyst, and the catalyst loading is 20%; the solid electrolyte is a cation exchange resin, and the flow rate of the aqueous solution is 1 mL / min. A voltage of 3V is applied to both ends of the reactor through an electrochemical workstation. After stabilization for 1 hour, the concentration of hydrogen peroxide produced continuously is 10-20%.
[0043] The 10-20% hydrogen peroxide produced by electrocatalysis is input into the falling film evaporator 2 through pipeline 102, and the hydrogen peroxide and aqueous solution are heated to 75-80°C under the action of the hot steam input by the jet pump 7 through pipeline 106. The gas phase output of the falling film evaporator has a concentration of 20-30% hydrogen peroxide and enters the bottom of the distillation tower through pipeline 105. The liquid phase is output from the bottom of the falling film evaporator through pipeline 104 and enters the circulation pump 5. The liquid phase is output from the circulation pump through pipeline 103 and input into the falling film evaporator for circulation evaporation. The steam at the top of the distillation tower 3 enters the steam jet pump through pipeline 107 and is used as a heat source. The operating temperature of the distillation tower is 40-45°C, and the operating pressure is 0.1MPa. Hydrogen peroxide with a concentration of 50-60% is extracted from the bottom of the distillation tower 3, mixed with methanol input from pipeline 108 and pipeline 109, and then enters the reaction system from the top of the fixed bed reactor 4, and undergoes epoxidation reaction with propylene gas entering from the bottom of the fixed bed reactor 4 through pipeline 110 under the action of titanium silicon molecular sieve catalyst to produce epoxy compounds. The reaction temperature is 50°C and the reaction pressure is 2MPa. The reaction liquid at the bottom of the reactor 4 is subsequently separated to obtain pure epoxy compounds. The concentration of hydrogen peroxide is calculated by iodine titration, and the selectivity of epoxy compounds in the product is calculated by chromatographic internal standard method. The results are shown in Table 1. .
[0044] Example 3
[0045] like Figure 2 As shown, hydrogen and oxygen are introduced into the electrocatalytic hydrogen peroxide synthesis device from the anode air inlet and the cathode air inlet at a flow rate of 20mL / min, respectively, with Pt / C coated on conductive carbon paper as the anode catalyst and carbon black after oxidation treatment as the cathode catalyst, and the catalyst loading is 10%; the solid electrolyte is a cation exchange resin, and the flow rate of the aqueous solution is 1mL / min. A voltage of 3V is applied to both ends of the reactor through an electrochemical workstation, and after stabilization for 1h, the concentration of hydrogen peroxide produced continuously is 2-10%.
[0046] The 2-10% hydrogen peroxide produced by electrocatalysis is input into the falling film evaporator 2 through pipeline 102. The hydrogen peroxide and aqueous solution are heated to 55-60°C under the action of the hot steam input by the jet pump 7 through pipeline 106. The gas phase output of the falling film evaporator has a concentration of 10-20% hydrogen peroxide and enters the bottom of the distillation tower through pipeline 105. The liquid phase is output from the bottom of the falling film evaporator through pipeline 104 and enters the circulation pump 5. The liquid phase is output from the circulation pump through pipeline 103 and input into the falling film evaporator for circulation evaporation. The steam at the top of the distillation tower 3 enters the steam jet pump through pipeline 107 and is used as a heat source. The operating temperature of the distillation tower is 40-45°C and the operating pressure is 0.1MPa. Hydrogen peroxide with a concentration of 35-40% is extracted from the bottom of the distillation tower 3, mixed with methanol input from pipeline 108 and pipeline 109, and then enters the reaction system from the top of the fixed bed reactor 4, and undergoes epoxidation reaction with ethylene gas entering from the bottom of the fixed bed reactor 4 through pipeline 110 under the action of titanium silicon molecular sieve catalyst to produce ethylene oxide. The reaction temperature is 60-55°C and the reaction pressure is 4MPa. The reaction liquid at the bottom of the reactor 4 is subsequently separated to obtain pure epoxide. The concentration of hydrogen peroxide is calculated by iodine titration, and the selectivity of epoxide in the product is calculated by chromatographic internal standard method. The results are shown in Table 1.
[0047] Example 4
[0048] like Figure 2 As shown, hydrogen and oxygen are introduced into the electrocatalytic hydrogen peroxide synthesis device from the anode air inlet and the cathode air inlet at a flow rate of 20mL / min, respectively, with Pt / C coated on conductive carbon paper as the anode catalyst and carbon black after oxidation treatment as the cathode catalyst, and the catalyst loading is 10%; the solid electrolyte is a cation exchange resin, and the flow rate of the aqueous solution is 1mL / min. A voltage of 3V is applied to both ends of the reactor through an electrochemical workstation, and after stabilization for 1h, the concentration of hydrogen peroxide produced continuously is 2-10%.
[0049] The 2-10% hydrogen peroxide produced by electrocatalysis is input into the falling film evaporator 2 through pipeline 102. The hydrogen peroxide and aqueous solution are heated to 55-60°C by the hot steam input by the jet pump 7 through pipeline 106. The gas phase output of the falling film evaporator has a concentration of 20-30% hydrogen peroxide and enters the bottom of the distillation tower through pipeline 105. The liquid phase is output from the bottom of the falling film evaporator through pipeline 104 and enters the circulation pump 5. The liquid phase is output from the circulation pump through pipeline 103 and input into the falling film evaporator for circulation evaporation. The steam at the top of the distillation tower 3 enters the steam jet pump through pipeline 107 and is used as a heat source. The operating temperature of the distillation tower is 40-45°C and the operating pressure is 0.1MPa. Hydrogen peroxide with a concentration of 35-40% is extracted from the bottom of the distillation tower 3, mixed with methanol input from pipeline 108 and pipeline 109, and then enters the reaction system from the top of the fixed bed reactor 4, and undergoes epoxidation reaction with propylene gas entering from the bottom of the fixed bed reactor 4 through pipeline 110 under the action of titanium silicon molecular sieve catalyst to produce propylene oxide. Among them, the reaction temperature is 60-55°C and the reaction pressure is 4MPa. The reaction liquid at the bottom of the reactor 4 is subsequently separated to obtain pure epoxide. The concentration of hydrogen peroxide is calculated by iodine titration, and the selectivity of epoxide in the product is calculated by chromatographic internal standard method. The results are shown in Table 1.
[0050] Comparative Example 1
[0051] The ethylene epoxidation reaction was carried out in the same manner as in Example 1, except that the commercially available 27.5% hydrogen peroxide was used without electrocatalytic synthesis and concentration.
[0052] Comparative Example 2
[0053] The propylene epoxidation reaction was carried out in the same manner as in Example 2, except that the commercially available 27.5% hydrogen peroxide was used without electrocatalytic synthesis and concentration.
[0054] Comparative Example 3
[0055] The ethylene epoxidation reaction was carried out in the same manner as in Example 1, except that the hydrogen peroxide was electrocatalytically synthesized and directly used in the back-end olefin epoxidation reaction without the concentration step.
[0056] Comparative Example 4
[0057] The propylene epoxidation reaction was carried out in the same manner as in Example 1, except that the hydrogen peroxide was electrocatalytically synthesized and directly used in the back-end olefin epoxidation reaction without the concentration step.
[0058] Table 1
[0059] serial number Hydrogen peroxide concentration Hydrogen peroxide conversion rate Epoxide selectivity Example 1 28％ 96.2 97.5％ Example 2 28％ 98.4％ 97.1％ Example 3 20％ 91.3％ 92.6％ Example 4 20％ 92.3％ 90.5％ Comparative Example 1 27.5％ 97.5％ 95.3％ Comparative Example 2 27.5％ 96.7％ 98.2％ Comparative Example 3 10％ 85％ 72.2％ Comparative Example 4 10％ 81.9％ 76.4％
[0060] It can be seen from the data in Table 1 that the process provided by the present invention can realize the process integration of electrocatalytic synthesis of hydrogen peroxide and olefin epoxidation reaction, and the hydrogen peroxide conversion rate and product selectivity can achieve the same effect as commercial hydrogen peroxide produced by the anthraquinone method. However, the production process and product separation of this process are greener.
[0061] The other processes of the present invention can adopt existing technologies.
[0062] The best embodiment of the present invention has been explained, and further developments of the present invention made by ordinary technicians in this field all fall within the protection scope of the patent of the present invention.
Claims
1. A system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide, characterized in that: The system comprises an electrocatalytic hydrogen peroxide synthesis unit, a hydrogen peroxide concentration device and a fixed bed reactor which are connected in sequence; The electrocatalytic hydrogen peroxide synthesis unit is formed by connecting a plurality of reactors in parallel, wherein the reactor is composed of an anode reinforcement plate, a cathode reinforcement plate and a solid electrolyte chamber; the concentration device includes a falling film evaporator and a distillation tower.
2. The system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide according to claim 1, characterized in that: An anode gas diffusion electrode is arranged between the anode reinforcement plate and the solid electrolyte chamber, and a cathode gas diffusion electrode is arranged between the anode gas diffusion electrode and the solid electrolyte chamber.
3. The system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide according to claim 1, characterized in that: The top of the distillation tower is connected to the upper part of the falling film evaporator through a steam jet pump.
4. The system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide according to claim 1, characterized in that: The top of the electrocatalytic hydrogen peroxide synthesis unit is connected to the falling film evaporator, the bottom of the falling film evaporator is connected to the top of the electrocatalytic hydrogen peroxide synthesis unit, and the output end of the lower part of the falling film evaporator is connected to the distillation tower.
5. The system for continuous green electrocatalytic synthesis of high-concentration hydrogen peroxide according to claim 1, characterized in that: The output end at the bottom of the distillation tower is connected to the fixed bed reactor.