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CN-121992419-A - System, method and application for preparing ketone by hydrogen peroxide mediated alkane conversion

CN121992419ACN 121992419 ACN121992419 ACN 121992419ACN-121992419-A

Abstract

The invention relates to a system, a method and application for preparing ketone by hydrogen peroxide mediated alkane conversion, comprising a two-step electrocatalytic reaction tank and a one-step thermocatalytic fixed bed reaction tank. The electrocatalytic reaction tank is respectively composed of a zero-gap membrane electrode tank and an improved flow electrochemical tank, the electrocatalytic reaction tank generates hydrogen and oxygen through electrocatalytic water, then the hydrogen and the oxygen are respectively introduced into the electrocatalytic reaction tank for oxidation reduction to prepare hydrogen peroxide, and the generated hydrogen peroxide is directly mixed with alkane gas through a tee joint and then enters a thermocatalytic fixed bed reactor, so that a ketone product can be prepared. Compared with the prior art, the method has excellent ketone selectivity and production efficiency, and is a more efficient and stable reaction system compared with the currently reported electrocatalytic or thermocatalytic technology.

Inventors

  • LI JUN
  • YAO KAILI
  • XIE RUIYAN

Assignees

  • 上海交通大学

Dates

Publication Date
20260508
Application Date
20241105

Claims (10)

  1. 1. The system for preparing ketone by hydrogen peroxide mediated alkane conversion is characterized by comprising an electrocatalytic reaction tank and a thermocatalytic fixed bed reactor (7), wherein the electrocatalytic reaction tank comprises a first electrocatalytic reaction tank (1) and a second electrocatalytic reaction tank (2), the first electrocatalytic reaction tank (1) generates hydrogen and oxygen through water electrolysis, then the hydrogen and the oxygen are respectively introduced into the second electrocatalytic reaction tank (2) for oxidation reduction preparation, hydrogen peroxide is obtained, the generated hydrogen peroxide is directly mixed with alkane gas through a tee joint (6) and then enters the thermocatalytic fixed bed reactor (7), and the ketone can be prepared by catalytic reaction.
  2. 2. The system for preparing ketone by hydrogen peroxide mediated alkane conversion according to claim 1, wherein the electrocatalytic reaction tank is a zero-gap membrane electrode tank, and comprises one or more membrane electrode assemblies and electrolyte, and each membrane electrode assembly comprises a proton exchange membrane and anode catalysts and cathode catalysts arranged on two sides of the proton exchange membrane.
  3. 3. The system for preparing ketone by hydrogen peroxide mediated alkane conversion according to claim 1, wherein the electrolyte of the first electrocatalytic reaction cell (1) is water; The electrolyte of the second electrocatalytic reaction tank (2) is a mixed solution of 0.01-1M H 2 SO 4 and 0.01-0.5M Na 2 SO 4 or 0.01-0.5M K 2 SO 4 .
  4. 4. The system for preparing ketone by hydrogen peroxide mediated alkane conversion according to claim 1, wherein the thermocatalytic fixed bed reactor (7) is a pipeline with an inner diameter of 3.5-10mm and a length of 100-500mm, and the interior of the pipeline is filled with a mixture of 2.5 titanium silicalite molecular sieve and quartz sand in a mass ratio of (0.05-0.8).
  5. 5. The system for preparing ketone by hydrogen peroxide mediated alkane conversion according to claim 4, wherein the Si/Ti ratio of the titanium silicalite is 25-60:1, and the particle size of the quartz sand is 20-200 meshes.
  6. 6. A method for preparing ketone by hydrogen peroxide mediated alkane conversion using the system of any one of claims 1 to 5, comprising the steps of: inputting water into a first electrocatalytic reaction tank (1) for electrolysis into oxygen and hydrogen, then respectively inputting the oxygen and the hydrogen into a second electrocatalytic reaction tank (2), inputting electrolyte into the second electrocatalytic reaction tank (2) through a peristaltic pump, performing oxidation reduction on the hydrogen and the oxygen in the second electrocatalytic reaction tank (2) to prepare hydrogen peroxide, mixing the hydrogen peroxide with alkane directly connected into a tee joint (6), and inputting the hydrogen peroxide into a thermal catalytic fixed bed reactor (7) for catalytic reaction to prepare ketone.
  7. 7. The method for preparing ketone by hydrogen peroxide mediated alkane conversion according to claim 6, wherein the current density applied to the first electrocatalytic reaction tank (1) is controlled to be 500-2000 ma/cm 2 ; Controlling the current density applied to the second electrocatalytic reaction tank (2) to be 100-1000 mA/cm 2 ; the flow rate of the electrolyte is 0.05-2mL/min, and the pressure gauge is 1 bar.
  8. 8. The method for preparing ketone by hydrogen peroxide mediated alkane conversion according to claim 6, wherein the flow rate of gas introduced into the thermocatalytic fixed bed reactor (7) is 0.1-50mL/min.
  9. 9. Use of the system according to any one of claims 1-4 for the conversion of alkanes to ketones.
  10. 10. The use according to claim 9, wherein the alkane comprises propane or butane.

Description

System, method and application for preparing ketone by hydrogen peroxide mediated alkane conversion Technical Field The invention belongs to the field of preparing ketone by alkane conversion, and particularly relates to a system, a method and application for preparing ketone by hydrogen peroxide mediated alkane conversion. Background The preparation of ketone products from alkanes in industrial production is of great importance. Current methods for producing ketone products are mainly based on oxidation processes, including high temperature oxidation and organic-mediated oxidation. The problems with the above-described processes are mainly that the high temperature conditions require a strong energy input leading to high energy consumption, and that the organic-mediated oxidation process typically yields a product that is a mixture of ketone and alcohol, requiring additional separation costs. Among the many ketone products, the acetone and butanone markets are 22% and 7% respectively, and are two typical representatives of the oxidation of linear alkanes to produce ketone products. Acetone is used as an important chemical, the annual yield exceeds 200 ten thousand tons, but China still depends on import in the aspect of acetone demand. At present, the industrial production of acetone with the dependency of more than 90 percent is dependent on a cumene method, which relates to a multi-step process flow, wherein propylene is prepared by dehydrogenation of propane, the process needs high temperature and high pressure conditions which are more than 773K and 30-70 MPa, then the generated propylene and benzene react under the conditions of 473K and 2-4 MPa to obtain cumene, the cumene further reacts to obtain acetone and phenol, and finally the two products are separated and purified through a multi-stage rectification process. The process requires high temperature and pressure conditions and uses a noble metal catalyst, and simultaneously easily causes carbon dioxide emission and large amount of wastewater emission. Butanone is also an important chemical product, and is mainly used for producing binders. By 2022, the butanone yield in China is about 50 ten thousand tons, and partial butanone yield is exported. The industrial production of butanone mainly adopts a normal butene hydration method, namely, normal butene is firstly added with Cheng Biancheng sec-butyl alcohol, and then the butanone is obtained through oxidative dehydrogenation. The process mainly has the defects of low yield, high three-waste emission, butene concentration technology and the like caused by high temperature and overlong reaction time. Patent CN201510129021.8 discloses a method for simultaneously producing propylene oxide and acetone, propylene and isopropanol are prepared into propylene oxide and acetone products under the catalysis of a titanium-silicon molecular sieve (TS-1) in the presence of oxygen, but acetone is mainly used as a co-product, and is obtained by oxidizing isopropanol, and the whole reaction system needs relatively high temperature and pressure conditions (40-160 ℃ and 1-5 mpa). Patent application CN118108575A discloses a process for the low temperature oxidation of propane to produce acetone by converting propane to acetone by high pressure (0.5-1 MPa) reactions in a medium containing an organic solvent at 200 ℃ with oxygen as the oxidant, which process produces various oxygenated products (such as acetone, acetic acid, formic acid, isopropanol, etc.), resulting in a selectivity of acetone of less than 60%. The use of renewable electricity as a driving force for a series of catalytic conversions is currently one of the mainstream technological routes for reducing energy consumption and waste emissions. Based on the green electro-oxidation process, the direct synthesis of the corresponding ketone product in the conversion of propane or butane is a new reform route for reducing energy consumption and realizing carbon emission reduction. However, the current density of the currently reported high selectivity electrocatalytic oxidation of alkanes such as propane is lower than 10mA/cm 2, which is far lower than the current density required for industrial application (300 mA/cm 2). This is because, when the current density increases, the potential increases to excessively oxidize alkanes such as propane, thereby forming carbon dioxide, and the product selectivity decreases. Disclosure of Invention The invention aims to overcome the defects in the prior art and provide a system, a method and application for preparing ketone by hydrogen peroxide mediated alkane conversion, which have high selectivity, high electron utilization efficiency and high stability. The invention can be realized by the following technical scheme that the system for preparing ketone by hydrogen peroxide mediated alkane conversion comprises an electrocatalytic reaction tank and a thermocatalytic fixed bed reactor (7), wherein the electrocatalytic re