CN-121992432-A - Preparation method of nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone and electrolysis device

Abstract

The invention provides a preparation method and an electrolysis device of a nickel phosphide catalyst suitable for preparing adipic acid by cyclohexanone electrooxidation, which belongs to the technical field of new energy chemical industry, and specifically comprises the steps of placing foam nickel into a high-pressure reaction kettle containing a mixed solution of nickel nitrate, ammonium fluoride and urea, reacting for 8-12 hours at 100-120 ℃, the nickel hydroxide is placed at the downstream of the tube furnace, the sodium hypophosphite is placed at the upstream of the tube furnace, and the nickel hydroxide is heated for 2-4 hours at 300-400 ℃ in an inert atmosphere, so that the nickel phosphide catalyst with high adipic acid selectivity in the cyclohexanone electrooxidation reaction is obtained, and the nickel phosphide catalyst is particularly suitable for high-current and long-time catalytic reaction, and the productivity and efficiency of unit time are greatly improved. Meanwhile, the difficult problem of complex preparation of the high-performance catalyst is overcome, the synthesis condition is mild, the process is simple, the reproducibility is good, expensive raw materials or complex equipment are not needed, the production cost is obviously reduced, and a solid foundation is laid for large-scale industrial application.

Inventors

• FENG XINRAN
• LI XU
• ZHANG XINYAN
• ZHENG TINGTING
• XIA CHUAN

Assignees

• 电子科技大学

Dates

Publication Date

20260508

Application Date

20260127

Claims (8)

1. 1. The preparation method of the nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone is characterized by comprising the following steps of: step1, foam nickel pretreatment; Step 2, placing the foam nickel into a high-pressure reaction kettle containing a mixed solution of nickel nitrate, ammonium fluoride and urea, reacting for 8-12 hours at 100-120 ℃, and drying to obtain nickel hydroxide; And 3, placing nickel hydroxide at the downstream of a tube furnace, placing sodium hypophosphite at the upstream of the tube furnace, heating at 300-400 ℃ for 2-4 hours under inert atmosphere, and cooling to obtain the nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone.
2. 2. The method for preparing the nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone according to claim 1, wherein the foam nickel in the step 1 is sheet-shaped, the plane size is 1 x 1 square centimeter-5 x 5 square centimeters, and the thickness is 0.1-0.3 centimeter.
3. 3. The method for preparing a nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone according to claim 2, wherein the concentration of nickel nitrate in the mixed solution in the step 2 is 0.01-0.2 mol/liter, the concentration of ammonium fluoride is 0.1-0.5 mol/liter, and the concentration of urea is 0.5-2 mol/liter.
4. 4. The method for preparing nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone according to claim 1, wherein the ratio of the adding amount of sodium hypophosphite to the area of nickel hydroxide in the step 3 is 1-3 grams per square centimeter.
5. 5. An electrolytic device for preparing adipic acid by electrooxidation of cyclohexanone is characterized in that a nickel phosphide catalyst obtained by the preparation method of the nickel phosphide catalyst according to any one of claims 1-4 is used as a working electrode, and cyclohexanone under an alkaline condition is used as an anode electrolyte.
6. 6. The electrolysis installation for the electrooxidation of cyclohexanone to adipic acid according to claim 5, characterized in that it is based on an H-cell, a flow cell, a membrane electrode cell or a membraneless cell design.
7. 7. The electrolytic device for preparing adipic acid by electrooxidation of cyclohexanone according to claim 5, wherein the electrolytic device is operated by adopting a constant current method or a constant voltage method, the anode current applied by the constant current method ranges from 0.05 ampere to 8.75 ampere, and the potential applied by the constant voltage method ranges from 0.5 volts to 4 volts.
8. 8. The electrolytic device for preparing adipic acid by electrooxidation of cyclohexanone according to claim 5, wherein the concentration of cyclohexanone in the anolyte is in the range of 0.05-1 mol/L.

Description

Preparation method of nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone and electrolysis device Technical Field The invention belongs to the technical field of new energy chemical industry, and particularly relates to a preparation method and an electrolysis device of a nickel phosphide catalyst suitable for preparing adipic acid by electrooxidation of cyclohexanone. Background Currently, nearly all commercial adipic acid production facilities worldwide employ the process route of "benzene-cyclohexane-KA oil-adipic acid". The route firstly carries out catalytic hydrogenation on benzene to generate cyclohexane, then converts the cyclohexane into a mixture of cyclohexanol and cyclohexanone (namely KA oil) through air oxidation under high temperature and high pressure, and finally utilizes nitric acid to oxidize the KA oil to prepare adipic acid. This conventional method, although mature in process, has serious environmental problems and technical drawbacks. The nitric acid oxidation step produces a significant amount of nitrogen oxides (NO x), including nitric oxide, nitrogen dioxide, and nitrous oxide, which are not only strongly irritating to the human respiratory tract, but also form the major precursors of acid rain and photochemical smog. Among these, nitrous oxide is also a gas with a strong greenhouse effect, whose impact potential on global warming is about 300 times that of carbon dioxide. From analysis of the nature of chemical reactions, the oxidation of KA oil by nitric acid to adipic acid involves complex heterogeneous redox reactions with reaction mechanisms involving multiple stages of radical initiation, chain growth, and termination. In the process, nitric acid not only serves as an oxidant, but also serves as a reaction medium, and a high-concentration (usually 50% -60%) nitric acid solution is needed to ensure the reaction efficiency. The highly corrosive medium has extremely high requirements on the materials of the reaction equipment, and needs to be manufactured by special stainless steel or titanium materials, thereby greatly increasing the equipment investment and maintenance cost. In addition, due to the strong oxidizing property of nitric acid, the selective control in the reaction faces serious challenges, and various byproducts such as dicarboxylic acids such as glutaric acid and succinic acid are often produced, so that the yield and purity of the adipic acid as a target product are reduced, and the difficulty and energy consumption of subsequent separation and purification are increased. In addition to environmental concerns, conventional processes face resource sustainability challenges. Benzene raw materials are completely derived from petroleum, namely non-renewable resources, and the production cost pressure of adipic acid is continuously increased along with the increasing exhaustion of global petroleum resources and the fluctuation of prices. Meanwhile, the hydrogenation process needs high-purity hydrogen and is carried out under high-temperature and high-pressure conditions, so that potential safety hazards and high energy consumption are caused. Aiming at the technical bottlenecks, the global scientific research and industry is actively searching for a green synthesis technology for replacing the traditional nitric acid route. Among them, the electrocatalytic oxidation of cyclohexanone to adipic acid is an environment-friendly technical path, and has been receiving a great deal of attention in recent years. The electrochemical synthesis technology uses electrons as a clean reaction reagent, and the reaction direction and the reaction speed are accurately controlled by adjusting the electrode potential, so that the use of a chemical oxidant or a reducing agent in the traditional oxidation-reduction process is avoided from the source, and the electrochemical synthesis technology is known as one of the representative technologies of green synthesis. In the field of adipic acid synthesis, the electrocatalytic oxidation research of cyclohexanone is subjected to an evolution process from basic electrochemical behavior exploration to catalyst design and process reinforcement, so that various technical routes are gradually formed. Despite the significant progress in the technological research of the electrooxidation of cyclohexanone to adipic acid, a number of key technical bottlenecks remain to be broken through before large-scale industrial applications are realized. Mass transfer limiting effects are the primary factor affecting the efficiency of electrooxidation. Cyclohexanone, as a hydrophobic organic substance, has extremely low solubility in aqueous electrolytes (less than 2.5 g per hundred ml of water at ambient temperature), resulting in slow mass transfer rates at the electrode surface and difficulty in adequate contact with the catalytically active sites. In conventional electrochemical reactors, the organic phase forms a