An apparatus and method for preparing ka oil

Abstract

This invention provides an apparatus and method for preparing KA oil, specifically relating to an apparatus and method for photo-plasma synergistic enhanced catalytic oxidation of cyclohexane to prepare KA oil. It includes: synergistically coupling plasma and a light field to confine the reaction within an insulated microfluidic channel, achieving simultaneous occurrence of the noble metal catalyst synthesis reaction and the catalytic oxidation reaction of cyclohexane. This invention can prepare the catalyst in situ at room temperature and pressure, and oxidize cyclohexane in one step to produce cyclohexanol and cyclohexanone (KA oil), achieving a cyclohexane conversion rate of 9-20% and a total selectivity of cyclohexanone and cyclohexanol of 89-98%. It has advantages such as safety, controllability, green efficiency, rapid and simple operation.

Description

Technical Field

[0001] This invention belongs to the field of cyclohexane oxidation for KA oil preparation technology, specifically relating to an apparatus and method for in-situ synthesis of catalysts and oxidation of cyclohexane at room temperature and pressure. Background Technology

[0002] The oxidation of cyclohexane has significant industrial production value. Its oxidation products, cyclohexanol and cyclohexanone, are commonly known industrially as KA oil and are important intermediates in the synthesis of adipic acid and caprolactam. The C-H bond energy of cyclohexane is as high as 97 kcal / mol, exhibiting chemical stability and resistance to breakage. Therefore, the method of oxidizing cyclohexane to produce KA oil generally requires extreme conditions of high temperature and pressure, demanding stringent environmental requirements and resulting in high energy consumption and high costs in industrial production. Furthermore, substances such as cyclohexane, cyclohexanone, and cyclohexanol in the production process have low flash points and wide explosion limits, making the reaction prone to combustion and explosion accidents. In recent years, with the introduction of energy conservation and emission reduction policies and the development of industrial safety production technologies, finding a simple, rapid, mild, safe, continuous, and efficient method to oxidize cyclohexane to prepare KA oil has become a current research hotspot.

[0003] Patent CN114426459A discloses a method for preparing KA oil by oxidizing cyclohexane using a microreactor. This method involves preheating and mixing liquid cyclohexane with oxygen at 120°C, then introducing the mixture into a microreactor where the temperature is 140°C–220°C and the pressure is 0.5 MPaG–4 MPaG. The resulting cyclohexane conversion rate is approximately 5%. This method requires pretreatment of the reactants at high temperatures and operates under extremely high pressure conditions, resulting in a very low cyclohexane conversion rate. Therefore, the reaction equipment is expensive, energy consumption is high, and reaction efficiency is low.

[0004] Patent CN110551001A discloses a method for preparing cyclohexane and cyclohexanone by decomposing cyclohexane using a single-stage or multi-stage microchannel reactor. This method can ensure uniform mixing of materials and greatly enhance the mass transfer efficiency between the gas and liquid phases. However, it still cannot solve the problems of requiring high temperature and high pressure conditions and excessive energy consumption in the reaction process.

[0005] Patent CN107670697B discloses a catalyst for the selective oxidation of cyclohexane under visible light and its preparation method. The method prepares an NH2-MIL-125(Ti) / P25 composite material for photocatalysis. However, the catalyst preparation steps are complicated, the reactant selectivity is low, the conversion rate of cyclohexane is less than 1%, and the reaction efficiency is low.

[0006] Traditional photocatalytic reactions are often inefficient and have poor selectivity. Furthermore, photocatalysts suffer from difficulties in preparation and poor stability, making them unsuitable for practical production processes. This invention synergistically couples plasma and light fields, effectively solving these problems, enhancing the reaction process, and providing a high-enthalpy, high-activity, and high-energy-density environment. This enables thermodynamically or kinetically infeasible reactions to occur, achieving unconventional preparation methods, which is of great significance for the green and efficient conduct of chemical reactions. High-energy electrons in plasma can replace traditional chemical reducing agents to excite and dissociate precursors, achieving the breaking and rearrangement of chemical bonds, shortening reaction time, improving reaction safety, and eliminating acid anion residues. As an emerging green chemical process, photocatalysis, under light irradiation, can excite electron transitions in the valence band of noble metal catalysts to form electron-hole pairs, generating extremely dense charge carriers to break high-energy chemical bonds, thereby catalyzing the oxidation of cyclohexane under mild conditions while ensuring good product selectivity.

[0007] By confining the reaction within a narrow reaction channel and precisely introducing the reaction solution using an injection pump, traditional batch production can be optimized into a continuous flow reaction. This ensures uniform material mixing, significantly enhances the mass transfer efficiency between the gas and liquid phases, and enables precise parameter control, process control, and reaction safety. Furthermore, designing the reaction channel as a vortex effectively increases the residence time of reactants, which not only significantly reduces the reactor volume and increases the specific surface area of ​​the reaction, but also ensures safe and stable operation of the device with low energy consumption, reducing equipment manufacturing and operating costs and facilitating industrial production. Summary of the Invention

[0008] Addressing the problems existing in current cyclohexane oxidation technologies, the applicant of this invention provides an apparatus and method for photo-plasma synergistic enhanced catalytic oxidation of cyclohexane to prepare KA oil. The apparatus of this invention couples a light field and plasma, designing a vortex-type insulated reaction channel to simultaneously perform nanocatalyst synthesis and cyclohexane oxidation. Under the synergistic effect of the light field and plasma, in-situ generation of the nanocatalyst is achieved, producing a large number of photons, high-energy electrons, and oxidizing active substances, activating and exciting cyclohexane to cyclohexyl radicals, thereby oxidizing it to cyclohexanol and cyclohexanone. This method offers advantages such as simplified reaction steps, reduced reaction costs, and improved reaction safety.

[0009] The technical solution of the present invention is as follows:

[0010] An apparatus for preparing KA oil includes an argon cylinder 1, an oxygen cylinder 2, a mass flow controller 3, a syringe pump 4, a three-way valve 5, a plasma-optical field generator 6, an oscilloscope 7, an AC power supply 8, a grounding electrode 9, a collector 10, an ice-water bath 11, and a fume hood 12. One end of the plasma-optical field generator 6 is connected to the first valve of the three-way valve 5, and the other end is connected to the product collector 10. The collector 10 is immersed in the ice-water bath 11 to facilitate product collection. The collector 10 and the ice-water bath 11 are placed in the fume hood 12. The second valve of the three-way valve 6 is connected to the argon cylinder 1 and the oxygen cylinder 2 respectively through the mass flow controller 3, and the third valve is connected to the syringe pump 4. There are two syringe pumps 4 connected in parallel, one for delivering the catalyst precursor solution and the other for delivering the cyclohexane reaction solution.

[0011] The plasma-light field generator 6 has a three-layer transparent box structure. The bottom layer 13-1 and the top layer 13-2 are equipped with light source emitting devices, which can generate visible light sources with different light intensities. The middle layer 14 is equipped with a vortex-type insulating reaction channel 15. The bottom plate and top plate of the middle layer 14 are transparent insulating glass plates, and conductive films are attached to the side near the light source. The conductive film on the bottom plate is connected to the AC power supply 8, and the conductive film on the top plate is connected to the grounding electrode 9. The AC power supply 8 is connected to an oscilloscope.

[0012] Furthermore, the upper top layer 13-2 and the lower bottom layer 13-1 of the plasma-light field generator 6 are 4-6 cm high and 11-11 to 16-16 cm long and wide.

[0013] Furthermore, the intermediate layer 14 of the plasma-light field generating device 6 has a height of 2~6mm and a length × width of 11×11~16×16cm; the light source can shine into the intermediate layer 14 through the upper and lower conductive glass plates of the intermediate layer 14.

[0014] Furthermore, the vortex-shaped insulating reaction channel 15 has an internal width of 0.1~2mm, an internal hollow channel length of 3~6m, and the reaction channel is made of one of glass, quartz, or ceramic.

[0015] Furthermore, the upper and lower conductive films of the intermediate layer 14 are connected to the positive and negative terminals of the power supply, forming a closed loop and generating a plasma field in the vortex-type insulating channel 15.

[0016] A method for preparing KA oil, wherein the method is performed using the apparatus described in any one of claims 1-5, and couples an optical field and a plasma field to achieve continuous and controllable occurrence of plasma catalyst and cyclohexane oxidation in time and space, and the preparation steps are as follows:

[0017] (1) Turn on the light sources in the bottom layer 13-1 and the top layer 13-2, and set the light intensity to 200~600mW / cm².-2 Provides stable illumination light;

[0018] (2) Preparation of precursor suspensions of noble metal ions and non-metallic materials: Using deionized water as solvent, add the noble metal materials and non-metallic materials to the deionized water, disperse them evenly by ultrasonication, and then place the precursor suspension in a syringe for later use; the concentrations of noble metal ions and non-metallic materials in the precursor suspension are 0.05~5mmol / L and 0.1~4mg / mL, respectively.

[0019] (3) Open argon cylinder 1 and oxygen cylinder 2, and set the flow rates of argon and oxygen through mass flow controller 3, wherein the argon flow rate is 100~200 sccm and the oxygen flow rate is 1~10 sccm.

[0020] (4) Gas is introduced into the vortex-type insulated reaction channel 15 for a period of time through the three-way valve 5 to discharge the impurity gas in the pipeline and reaction channel;

[0021] (5) Place the syringes containing cyclohexane and precursor suspension on two syringe pumps 4 respectively, and connect them to the three-way valve 5. Set the rate of cyclohexane solution entering the channel on the syringe pump 4 to 0.1~1 mL / min and the rate of precursor suspension to 1~3 mL / min.

[0022] (6) Turn on the injection pump of the precursor suspension. The precursor suspension enters the vortex-type insulated reaction channel 15 at a set rate. When the gas and liquid phases of the reaction channel are balanced, turn on the AC power supply 8 and set the plasma voltage to 10~40V to break down the argon gas to generate plasma, reduce the noble metal solution to noble metal nanoparticles, and generate a plasma catalyst.

[0023] (7) After the precursor suspension is injected into the reaction channel for 10 min to 15 min, turn on the cyclohexane injection pump and introduce cyclohexane into the reactor at a set rate. Under the irradiation of light, the noble metal nanoparticles will generate high-energy electron-hole pairs due to the surface plasmon resonance effect, thereby catalytically oxidizing cyclohexane into cyclohexanol and cyclohexanone.

[0024] (8) The product flows out from the outlet of the vortex-type insulated reaction channel 15 under the impetus of liquid and gas, and the collector 10 is immersed in the ice water tank 11 for cooling and collecting the product, reducing the evaporation of the product solution.

[0025] Furthermore, the plasma catalyst is one or a mixture of two or more of gold nanoparticles, silver nanoparticles, platinum nanoparticles, and palladium nanoparticles, and the non-metallic material used as the catalyst support is a dielectric nanomaterial, specifically one of silicon dioxide, titanium dioxide, aluminum oxide, graphene, and carbon nanotubes.

[0026] Furthermore, the plasma catalyst can be generated in situ within the reaction channel without the need for filtration and drying pretreatment, and can proceed simultaneously with the cyclohexane oxidation reaction.

[0027] Furthermore, the reaction conditions are ambient temperature and pressure, and the reaction time is 5-15 minutes.

[0028] Furthermore, the conversion rate of cyclohexane is 9-20%, and the total selectivity of cyclohexanone and cyclohexanol is 89-98%.

[0029] The beneficial technical effects of this invention are as follows:

[0030] (1) This invention uses plasma and light field synergistic enhancement technology. It utilizes the characteristics of plasma, such as strong reactivity, high enthalpy, concentrated energy, environmental friendliness, and no residue, to excite high-energy electron-holes in noble metal nanomaterials under light field conditions. This provides a new medium rich in photons, high-energy electrons, and active groups for the reaction, thereby realizing the catalytic continuous oxidation of cyclohexane to cyclohexanol and cyclohexanone at room temperature and pressure, avoiding the traditional harsh reaction conditions and expensive reaction equipment.

[0031] (2) This invention utilizes the synergistic generation of high-energy electrons, photons, and oxygen-containing active substances from plasma and light fields to replace traditional chemical reagents, activating cyclohexane into cyclohexyl radicals, which are then oxidized into cyclohexanol and cyclohexanone. Furthermore, noble metal nanomaterials, due to their surface plasmon resonance effect, generate a large number of high-energy electron-hole pairs under light excitation, producing a large number of electrons that can further drive chemical transformation and break chemical bonds. The method described in this invention allows the reaction to operate stably under an AC electric field and light field of only tens of watts, eliminating the need for large amounts of organic reagents. This saves production energy and reduces environmental pollution. Simultaneously, by avoiding the intervention of other chemical reagents, the reaction process is greatly simplified.

[0032] (3) This invention uses efficient, safe and environmentally friendly photocatalytic technology to propose a solution for green industrial production and sustainable energy development.

[0033] (4) This invention utilizes an insulated reaction channel to optimize the traditional batch reaction into a continuous flow reaction. The reactant flow rate and gas flow rate can be set by parameter control, which can realize the real-time generation of precious metal catalysts, adjust the conversion rate of cyclohexane and the selectivity of products. No manual real-time monitoring is required during the reaction process, which can realize refined and automated production.

[0034] (5) The present invention can uniformly mix gas and liquid phases in the channel, which increases gas-liquid transfer and can achieve efficient oxidation in a low oxygen atmosphere. It can effectively avoid the occurrence of hot spots and chain explosions and ensure safety in the reaction process.

[0035] (6) The vortex-type reaction channel designed in this invention can reach a length of 3-6m in a relatively small space, providing a high specific surface area for the reaction and significantly reducing the volume of the reaction device. Therefore, this invention can effectively reduce device energy consumption, save production costs, ensure the safety of the reaction process, and improve reaction conversion efficiency, and has important application value for industrial production. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the apparatus for producing KA oil by oxidizing cyclohexane according to the present invention.

[0037] Figure 2 This is an enlarged view of the plasma-light field generator.

[0038] Figure 3 This is an SEM image of the noble metal catalyst in Invention Example 1.

[0039] Figure 4 This is a TEM image of the noble metal catalyst in Invention Example 1.

[0040] Figure 5 This is an SEM image of the noble metal catalyst in Invention Example 1.

[0041] Figure 6 This is a TEM image of the noble metal catalyst in Invention Example 1.

[0042] In the diagram: 1 Argon cylinder, 2 Oxygen cylinder, 3 Mass flow controller, 4 Injection pump, 5 Three-way valve, 6 Plasma-light field generator, 7 Oscilloscope, 8 AC power supply, 9 Grounding electrode, 10 Collector, 11 Ice water bath, 12 Fume hood, 13-1 Lower bottom layer, 13-2 Upper top layer, 14 Middle layer, 15 Vortex-type insulated reaction channel. Detailed Implementation

[0043] The apparatus includes an argon cylinder, an oxygen cylinder, a mass flow controller, a syringe pump, a transparent insulating enclosure, a three-way valve, a plasma microreactor (vortex-type insulating reaction channel 15), an oscilloscope, an AC power supply, a collector, an ice water bath, a fume hood, a metal plate, and a grounding electrode.

[0044] The present invention will now be described in detail through specific embodiments.

[0045] In the examples, cyclohexane conversion rate = (number of moles of product / number of moles of cyclohexane fed) × 100%

[0046] In the examples, the conversion rate of cyclohexanol and cyclohexanol = (moles of cyclohexanol produced + moles of cyclohexanone produced) / cyclohexane conversion rate × 100%

[0047] Example 1

[0048] Reference Figure 1 ,

[0049] The apparatus includes an argon cylinder 1, an oxygen cylinder 2, a mass flow controller 3, a syringe pump 4, a three-way valve 5, a plasma-optical field generator 6, an oscilloscope 6, an AC power supply 8, a grounding electrode 9, a collector 10, an ice water tank 11, and a fume hood 12. One end of the plasma-optical field generator 6 is connected to the first valve of the three-way valve 5, and the other end is connected to the product collector 10. The collector 10 is immersed in the ice water tank 11 to facilitate product collection. The second valve of the three-way valve 5 is connected to both the argon cylinder 1 and the oxygen cylinder 2 via the mass flow controller 3, and the third valve is connected to the syringe pump 4. There are two syringe pumps 4 connected in parallel. One pump is used to deliver the catalyst precursor solution, and the other pump is used to deliver the cyclohexane reaction solution.

[0050] The plasma-light field generator 6 has a three-layer transparent box structure. The bottom layer 13-1 and the top layer 13-2 are equipped with light source emitting devices, which can generate visible light sources with different light intensities. The middle layer 14 is equipped with a vortex-type insulating reaction channel 15. The bottom plate and top plate of the middle layer 14 are transparent insulating glass plates, and conductive films are attached to the side near the light source. The conductive film of the bottom plate is connected to the AC power supply 8, and the conductive film of the top plate is connected to the grounding electrode 9. The AC power supply 8 is connected to the oscilloscope 7.

[0051] The upper layer 13-2 and lower layer 13-1 of the plasma-light field generator 6 are 4cm high and 12×12cm long and wide.

[0052] The intermediate layer 14 of the plasma-light field generator 6 is 4mm high and 12×12cm long and wide; the light source can shine into the intermediate layer 14 through the upper and lower conductive glass plates.

[0053] The vortex-shaped insulated reaction channel 15 has an internal width of 0.5 mm and an internal hollow channel length of 5 m. The reaction channel is made of glass.

[0054] Using deionized water as a solvent, 50 mL of 1 mmol / L chloroauric acid solution was prepared, and 10 mg of nano-alumina powder was added. The resulting suspension was then dispersed in an ultrasonic machine for 15 min to obtain the photocatalytic precursor.

[0055] After setting up the reaction apparatus, turn on the light source and set the light intensity to 300 mW / cm². -2Argon flow rate was set to 200 sccm and oxygen flow rate to 2 sccm. The mixed gas was introduced into the reaction system for about 5 minutes to clean the insulated reaction channel and pipelines of impurities. The catalyst precursor solution was injected into the system using a syringe pump at a flow rate of 1.5 mL / min. After the gas and liquid phases reached equilibrium, the AC power supply was turned on, and an insulation voltage of 25V was applied to the upper metal plate of the transparent insulating box to break down the argon gas and generate plasma. The power supply current was adjusted and stabilized. Under the action of the plasma field, chloroauric acid was reduced to gold nanoparticles, thereby synthesizing the plasma catalyst. After the chloroauric acid solution was introduced for 10 minutes, the cyclohexane syringe pump was turned on, and the cyclohexane introduction rate was set to 0.2 mL / min. Under photoexcitation, the electrons on the surface of the noble metal catalyst could undergo collective oscillation, effectively capturing the energy of the light source and storing it in the form of high-energy charges, thereby activating oxygen and realizing the reaction between the cyclohexane solution and oxygen to generate cyclohexanol and cyclohexanone products. The product solution will flow from the right end of the plasma reactor into a collector, which is immersed in an ice-water bath to cool the product and reduce evaporation.

[0056] Gas chromatography analysis of the liquid cooled in an ice-water bath revealed a cyclohexane conversion rate of 12.5% ​​and a total selectivity of 93.2% for cyclohexanone and cyclohexanol, with a selectivity of 63.8% for cyclohexanone and 29.4% for cyclohexanol.

[0057] Example 2

[0058] The processing and operating conditions are the same as in Example 1, except that the argon flow rate is 200 sccm and the oxygen flow rate is 6 sccm.

[0059] Gas chromatography analysis of the liquid cooled in the ice water bath in Example 2 showed a cyclohexane conversion rate of 14.1% and a total selectivity of 91.5% for cyclohexanone and cyclohexanol, with a selectivity of 61.5% for cyclohexanone and 30.0% for cyclohexanol.

[0060] Example 3

[0061] The processing and operating conditions are the same as in Example 1, except that the argon flow rate is 200 sccm and the oxygen flow rate is 10 sccm.

[0062] Gas chromatography analysis of the liquid cooled in the ice water bath in Example 3 showed a cyclohexane conversion rate of 13.4% and a total selectivity of 95.7% for cyclohexanone and cyclohexanol, with a selectivity of 63.3% for cyclohexanone and 32.4% for cyclohexanol.

[0063] Example 4

[0064] The processing and operating conditions are the same as in Example 1, except that the chloroauric acid solution prepared is 2 mmol / L.

[0065] Gas chromatography analysis of the liquid cooled in the ice water bath in Example 4 showed a cyclohexane conversion rate of 15.2% and a total selectivity of 93.5% for cyclohexanone and cyclohexanol, with a selectivity of 67.2% for cyclohexanone and 26.3% for cyclohexanol.

[0066] Example 5

[0067] The processing and operating conditions are the same as in Example 1, except that the chloroauric acid solution prepared is 4 mmol / L.

[0068] Gas chromatography analysis of the liquid cooled in the ice-water bath in Example 5 revealed a cyclohexane conversion rate of 17.4% and a total selectivity of 92.8% for cyclohexanone and cyclohexanol, with a selectivity of 66.3% for cyclohexanone and 26.5% for cyclohexanol.

[0069] Example 6

[0070] The processing and operating conditions are the same as in Example 1, except that the noble metal ion solution used as the catalyst precursor is silver nitrate solution, and the non-metallic material used as the catalyst precursor is nano-silica.

[0071] Gas chromatography analysis of the liquid cooled in the ice-water bath in Example 6 revealed a cyclohexane conversion rate of 11.7% and a total selectivity of 89.1% for cyclohexanone and cyclohexanol, with a selectivity of 58.9% for cyclohexanone and 30.2% for cyclohexanol.

[0072] Example 7

[0073] The processing and operating conditions are the same as in Example 1, except that the cyclohexane inlet rate is 0.4 mL / min.

[0074] Gas chromatography analysis of the liquid cooled in the ice-water bath in Example 7 revealed a cyclohexane conversion rate of 10.4% and a total selectivity of 92.6% for cyclohexanone and cyclohexanol, with a selectivity of 61.5% for cyclohexanone and 30.2% for cyclohexanol.

[0075] Example 8

[0076] The processing and operating conditions are the same as in Example 1, except that the cyclohexane inlet rate is 0.8 mL / min.

[0077] Gas chromatography analysis of the liquid cooled in the ice-water bath in Example 8 revealed a cyclohexane conversion rate of 9.7% and a total selectivity of 90.6% for cyclohexanone and cyclohexanol, with a selectivity of 58.9% for cyclohexanone and 31.7% for cyclohexanol.

[0078] Example 9

[0079] The processing and operating conditions are the same as in Example 1, except that the AC power supply voltage is 30V.

[0080] Gas chromatography analysis of the liquid cooled in the ice-water bath in Example 9 revealed a cyclohexane conversion rate of 13.1% and a total selectivity of 88.3% for cyclohexanone and cyclohexanol, with a selectivity of 60.8% for cyclohexanone and 27.5% for cyclohexanol.

[0081] Example 9

[0082] The processing and operating conditions are the same as in Example 1, except that the AC power supply voltage is 40V.

[0083] Gas chromatography analysis of the liquid cooled in the ice-water bath in Example 7 revealed a cyclohexane conversion rate of 15.5% and a total selectivity of 88.7% for cyclohexanone and cyclohexanol, with a selectivity of 58.9% for cyclohexanone and 29.8% for cyclohexanol.

[0084] Table 1 shows the conversion rate of cyclohexane and the selectivity of cyclohexanol and cyclohexanone under the conditions of Examples 1-10.

[0085]

[0086] The above embodiments are merely illustrative of the process flow of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, or improvements made by those skilled in the art without departing from the principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of preparing KA oil, characterized by, It is achieved using an apparatus for preparing KA oil, which includes an argon cylinder (1), an oxygen cylinder (2), a mass flow controller (3), an injection pump (4), a three-way valve (5), a plasma-light field generator (6), an oscilloscope (7), an AC power supply (8), a grounding electrode (9), a collector (10), an ice water tank (11), and a fume hood (12). One end of the plasma-light field generator (6) is connected to the first valve of the three-way valve (5), and the other end is connected to the product collector (10). The collector (10) is immersed in the ice water tank (11) to facilitate product collection. The collector (10) and the ice water tank (11) are placed in the fume hood (12). The second valve of the three-way valve (5) is connected to the argon cylinder (1) and the oxygen cylinder (2) respectively through the mass flow controller (3), and the third valve is connected to the injection pump (4). There are two injection pumps (4) in total, which are connected in parallel. One of them is used to transport the catalyst precursor solution, and the other is used to transport the cyclohexane reaction solution. The plasma-light field generator (6) is a three-layer transparent box structure. The bottom layer (13-1) and the top layer (13-2) are equipped with light source emitting devices, which can generate visible light sources with different light intensities. The middle layer (14) is equipped with a vortex-type insulating reaction channel (15). The bottom plate and top plate of the middle layer (14) are transparent insulating glass plates. A conductive film is attached to the side of the transparent insulating glass plate near the light source. The conductive film of the bottom plate is connected to the AC power supply (8), and the conductive film of the top plate is connected to the grounding electrode (9). The AC power supply (8) is connected to the oscilloscope (7). By coupling optical and plasma fields, the continuous and controllable occurrence of plasma catalyst and cyclohexane oxidation in time and space is achieved. The preparation steps are as follows: (1) Turn on the light source in the lower bottom layer (13-1) and the upper top layer (13-2), and set the light intensity to 200-600 mW / cm 2 , to provide stable irradiation light; (2) Preparation of precursor suspensions of noble metal ions and non-metallic materials: Using deionized water as solvent, add the noble metal materials and non-metallic materials to the deionized water, disperse them evenly by ultrasonication, and then place the precursor suspension in a syringe for later use; the concentrations of noble metal ions and non-metallic materials in the precursor suspension are 0.05~5mmol / L and 0.1~4mg / mL, respectively. (3) Open the argon cylinder (1) and the oxygen cylinder (2), and set the flow rates of argon and oxygen through the mass flow controller (3), wherein the argon flow rate is 100~200 sccm and the oxygen flow rate is 1~10 sccm; (4) Gas is introduced into the vortex-type insulated reaction channel (15) for a period of time through the three-way valve (5) to discharge the impurity gas in the pipeline and reaction channel; (5) Place the syringes containing cyclohexane and precursor suspension on two syringe pumps (4) respectively, and connect them to the three-way valve (5). Set the rate of cyclohexane solution entering the channel on the syringe pump (4) to 0.1~1 mL / min and the rate of precursor suspension to 1~3 mL / min. (6) Turn on the injection pump of the precursor suspension. The precursor suspension enters the vortex-type insulated reaction channel (15) at a set rate. When the gas and liquid phases of the reaction channel are in equilibrium, turn on the AC power supply (8) and set the plasma voltage to 10~40V to break down the argon gas to generate plasma, reduce the noble metal solution to noble metal nanoparticles, and generate a plasma catalyst. (7) After the precursor suspension is injected into the reaction channel for 10 min to 15 min, turn on the cyclohexane injection pump and introduce cyclohexane into the reactor at a set rate. Under light irradiation, the noble metal nanoparticles will form high-energy electron-hole pairs due to the surface plasmon resonance effect, generating high-density charge carriers, which will activate cyclohexane into cyclohexyl radicals, thereby oxidizing it into cyclohexanol and cyclohexanone. (8) The product flows out from the outlet of the vortex-type insulated reaction channel (15) under the impetus of the solution and gas, and the collector (10) is immersed in the ice water tank (11) to cool and collect the product, thereby reducing the evaporation of the product solution.

2. A process for the preparation of KA oil as claimed in claim 1 wherein, The upper top layer (13-2) and lower bottom layer (13-1) of the plasma-light field generator (6) are 4-6 cm high and 11-11 to 16-16 cm long and wide.

3. The method of claim 1, wherein the KA oil is prepared by the steps of: The intermediate layer (14) of the plasma-light field generator (6) has a height of 2~6mm and a length × width of 11×11~16×16cm; the light source can shine into the intermediate layer (14) through the upper and lower transparent glass plates.

4. The method of claim 1, wherein the KA oil is prepared by the steps of: The vortex-type insulated reaction channel (15) has an internal width of 0.1~2mm and an internal hollow channel length of 3~6m. The reaction channel is made of one of glass, quartz, or ceramic.

5. The method of claim 1, wherein the KA oil is prepared by the steps of: The upper and lower conductive films of the intermediate layer (14) are connected to the positive and negative terminals of the power supply to form a closed loop, generating a plasma field in the vortex-type insulating reaction channel (15).

6. The method of claim 1, wherein the KA oil is prepared by the steps of: The plasma catalyst is one or a mixture of two or more of gold nanoparticles, silver nanoparticles, platinum nanoparticles, and palladium nanoparticles. The non-metallic material is used as a catalyst support and is a dielectric nanomaterial, specifically one of silicon dioxide, titanium dioxide, aluminum oxide, graphene, and carbon nanotubes.

7. The method of claim 1, wherein the KA oil is prepared by the steps of: The plasma catalyst is generated in situ within the reaction channel, eliminating the need for filtration and drying pretreatment, and proceeds simultaneously with the cyclohexane oxidation reaction.

8. The method of claim 1, wherein the KA oil is prepared by the steps of: The reaction conditions are ambient temperature and pressure, and the reaction time is 5-15 minutes.

9. The method of claim 1, wherein the KA oil is prepared by the steps of: The conversion rate of cyclohexane is 9-20%, and the total selectivity of cyclohexanone and cyclohexanol is 89-98%.

Images