Green, rapid, efficient and low-cost KA oil synthesis method and device

Abstract

The invention provides a green, rapid, efficient and low-cost KA oil synthesis method and device, and the method comprises the following steps: (1) dissolving cyclohexane and hydrogen peroxide in acetonitrile-water to obtain a reaction solution; (2) carrying out ultrasonic atomization on the reaction liquid to form micro-droplets, then condensing the micro-droplets, continuously carrying out ultrasonic atomization to form micro-droplets after the micro-droplets fall back to the reaction liquid again, and circulating ultrasonic atomization-condensation operation to obtain KA oil; furthermore, the reaction liquid also comprises hydrochloric acid. According to the method, the surface characteristics of the micro-droplets are utilized, the micro-droplets are used as a micro-reactor, oxidation reaction is carried out on the surfaces of the micro-droplets, cyclohexane is oxidized to generate KA oil, the synthesis method is rapid in reaction, short in reaction time, far shorter than several hours required by the prior art, high in selectivity, few in by-products, capable of being carried out at normal temperature and normal pressure, mild in reaction condition, high in yield and suitable for industrial production. The method has good reaction effect and important industrial value, and belongs to the technical field of organic synthesis.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a method and device for synthesizing KA oil in a green, rapid, efficient and low-cost manner. Background Art

[0002] KA oil is a mixture mainly composed of cyclohexanone and cyclohexanol. In the field of chemical industry, as an extremely important organic chemical raw material, KA oil is a key intermediate for synthesizing many high-performance polymers such as polyamide fibers (such as nylon 6 and nylon 66), and has a wide range of applications in many industries such as textile, automotive, and electronics, and its market demand continues to grow. The preparation process of KA oil mostly uses cyclohexane as the raw material. Since cyclohexane belongs to saturated hydrocarbons, the C-H bond energy of it is large and the stability is strong. Therefore, the reaction usually requires harsh reaction conditions such as high temperature and pressure, strong oxidants, and addition of stoichiometric catalysts.

[0003] In industrial production, the cyclohexane oxidation method is a common synthesis route. However, this method has some significant defects: First, the yield of KA oil is low. During the production process, in order to prevent over-oxidation, the yield of KA oil is often controlled at about 5%. Second, a metal catalyst needs to be added during the reaction process, resulting in high production costs. Moreover, during the reaction process, the catalyst may be deactivated due to poisoning, carbon deposition, sintering, etc. In addition, improper post-treatment of the used catalyst will cause great harm to the environment, which does not meet the needs of green and sustainable development. Finally, the reaction time of this method is long, taking several hours, indirectly leading to an increase in production costs. Therefore, it is very necessary to develop a new method for synthesizing KA oil that is environmentally friendly, safe and economical, green and rapid, and has a high yield. Summary of the Invention

[0004] The technical solution adopted by the present invention is to provide a method and device for synthesizing KA oil in a green, rapid, efficient and low-cost manner to solve the technical problems of low yield, high cost, great harm to the environment and long reaction time existing in the existing KA oil synthesis methods.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: to provide a method for synthesizing KA oil in a green, rapid, efficient and low-cost manner, including the following steps:

[0006] (1) Dissolve cyclohexane and hydrogen peroxide in acetonitrile-water to obtain a reaction solution;

[0007] (2) Perform ultrasonic atomization on the reaction solution to form micro-droplets, then condense the micro-droplets. Wait for the micro-droplets to fall back into the reaction solution again, and continue to form micro-droplets through ultrasonic atomization. Perform cyclic ultrasonic atomization-condensation operation to obtain KA oil.

[0008] Preferably, in step (1), the molar ratio of cyclohexane to hydrogen peroxide is 1:5 - 1:50, the volume fraction of acetonitrile in the total volume of the reaction solution is 20 - 90%, and the volume fraction of water in the total volume of the reaction solution is 10% - 80%.

[0009] Preferably, in step (2), both ultrasonic atomization and condensation are carried out at normal temperature and pressure. The frequency of ultrasonic atomization is 1 - 10 Hz, and the total time of the ultrasonic atomization - condensation cycle operation is 5 - 80 min.

[0010] Preferably, in step (1), the reaction solution further includes hydrochloric acid, and the molar ratio of hydrochloric acid to hydrogen peroxide is 0.01:1 - 5:1.

[0011] The present invention also provides a device for green, rapid, efficient, and low - cost synthesis of KA oil. Using the above - mentioned method for green, rapid, efficient, and low - cost synthesis of KA oil, it includes an ultrasonic atomizer. The top of the ultrasonic atomizer is provided with a reaction cavity. A reaction chamber is arranged inside the reaction cavity. An ultrasonic atomization sheet is provided on the ultrasonic atomizer. The ultrasonic atomization sheet is communicated with the reaction chamber. A condensation sheet is provided at the top of the reaction chamber.

[0012] Preferably, the condensation sheet includes a quartz glass sheet; sealing rings are provided between the ultrasonic atomizer and the reaction cavity, and between the condensation sheet and the reaction cavity.

[0013] Preferably, a fixed cover is provided at the top of the condensation sheet, and the fixed cover is detachably connected to the reaction cavity; a fixed base is provided at the bottom of the ultrasonic atomizer, and fixing holes are provided on the fixed base.

[0014] Preferably, the height between the ultrasonic atomization sheet and the condensation sheet is 6 - 10 cm.

[0015] Preferably, the reaction cavity is provided with a plurality of gas channels, and the gas channels are communicated with the reaction chamber.

[0016] Preferably, the method of using the above - mentioned device for green, rapid, efficient, and low - cost synthesis of KA oil includes the following steps:

[0017] (1) Open the fixed cover, remove the condensation sheet, add the reaction solution into the reaction chamber. The reaction solution contacts the ultrasonic atomization sheet, and then install the condensation sheet and the fixed cover;

[0018] (2) Connect the ultrasonic nebulizer to the power supply and start it. The ultrasonic atomization sheet performs ultrasonic atomization on the reaction solution to form micro-droplets. During the ultrasonic atomization process, the micro-droplets rise, reach the top of the reaction chamber, come into contact with the condensation sheet and are condensed. After condensation, the micro-droplets fall back. When the micro-droplets fall back into the reaction solution again, come into contact with the ultrasonic atomization sheet and continue to form micro-droplets through ultrasonic atomization. By cycling the ultrasonic atomization-condensation operation, KA oil is obtained.

[0019] The present invention provides a method for synthesizing KA oil that is green, rapid, efficient, and low-cost. Using cyclohexane as the raw material, hydrogen peroxide as the green oxidant, and acetonitrile-water as the solvent, under the action of ultrasonic atomization, the reaction solution is "fragmented" into micro-droplets, and an oxidation reaction occurs on the surface of the micro-droplets to generate KA oil. The micro-droplets formed by ultrasonic atomization rise, are condensed when encountering cold, and then fall back. When they fall back into the reaction solution, they continue to form micro-droplets through ultrasonic atomization. By cycling the ultrasonic atomization-condensation operation, KA oil is continuously generated. The method for synthesizing KA oil that is green, rapid, efficient, and low-cost of the present invention can also add hydrochloric acid as a promoter to inhibit the decomposition of hydrogen peroxide, promote hydrogen peroxide to generate more hydroxyl radicals, promote the progress of the forward reaction, and improve the reaction rate and selectivity of the oxidation reaction. The present invention also provides a device for synthesizing KA oil that is green, rapid, efficient, and low-cost.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The present invention utilizes the surface characteristics of micro-droplets, uses micro-droplets as micro-reactors, applies them to the activation reaction of cycloalkanes, and an oxidation reaction occurs on the surface of the micro-droplets to oxidize cyclohexane to generate KA oil. The synthesis method has a rapid reaction, a short reaction time, which is much faster than the several hours required by the prior art, high selectivity, few by-products, and can be carried out under normal temperature and pressure without high temperature and high pressure. The reaction conditions are mild, the yield is high, and the reaction effect is good, having important industrial value.

[0022] (2) The synthesis method of the present invention does not require any catalyst, reducing the cost brought by the catalyst, and at the same time avoiding the resource consumption and possible pollution caused by the synthesis of the catalyst. In addition, the raw materials required for the synthesis method of the present invention are only cyclohexane, the green oxidant hydrogen peroxide, and the promoter hydrochloric acid, which is environmentally friendly and green.

[0023] (3) The synthesis method of the present invention can also add hydrochloric acid as a promoter. Hydrogen peroxide will decompose under alkaline conditions. After adding hydrochloric acid, hydrogen ions will inhibit the decomposition of hydrogen peroxide, promote hydrogen peroxide to generate more hydroxyl radicals, promote the progress of the forward reaction, improve the reaction rate and selectivity of the oxidation reaction, and improve the effect of the oxidation reaction.

[0024] (4) The reaction device of the present invention is entirely made of 316L stainless steel, which is strong and durable. Sealing rings are provided between the ultrasonic nebulizer and the reaction chamber, and between the condenser sheet and the reaction chamber inside the reaction device. The airtightness of the entire reaction device is good. Even if a gas reaction occurs, it can prevent the leakage of raw materials, avoid material loss and potential safety hazards. At the same time, it also prevents impurities such as moisture and oxygen in the outside world from entering the reaction device, reduces the occurrence of side reactions, and ensures the reaction rate and reaction equilibrium.

[0025] (5) The reaction device of the present invention can replace the reaction chamber with different sizes according to requirements, and can also replace the ultrasonic nebulizer with different frequencies and powers to generate micro-droplets of different sizes and quantities, thereby affecting the reaction time, and reaction kinetics research can be carried out accordingly.

[0026] (6) The reaction device of the present invention can apply ultraviolet light to the reaction chamber through a quartz glass sheet for photocatalysis according to requirements, which can meet the requirements of various organic synthesis reactions; in addition, various reaction gases can be introduced into the reaction chamber through the gas channel according to requirements, which can meet the reaction requirements of various gas atmospheres. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of a device for green, rapid, efficient and low-cost synthesis of KA oil provided in Embodiment 2 of the present invention;

[0029] Figure 2 is Figure 1 a schematic cross-sectional structural diagram of the device for green, rapid, efficient and low-cost synthesis of KA oil shown;

[0030] Figure 3 It is a mass spectrum of the product prepared in Embodiment 7 of the present invention;

[0031] Figure 4 It is a secondary mass spectrum of the product prepared in Embodiment 7 of the present invention;

[0032] Figure 5 It is a mass spectrum of cyclohexanol standard;

[0033] Figure 6 It is a secondary mass spectrum of cyclohexanol standard;

[0034] Figure 7It is the mass spectrum of cyclohexanone standard product;

[0035] Figure 8 It is the secondary mass spectrum of cyclohexanone standard product.

[0036] Explanation of symbols in the figure:

[0037] 1. Ultrasonic nebulizer; 101. Ultrasonic atomization sheet; 2. Reaction cavity; 201. Reaction chamber; 202. Gas channel; 3. Condensing sheet; 4. Fixed base; 401. Fixed hole; 5. Fixed cover; 6. Sealing ring. Specific implementation manners

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. The raw materials and devices used in the present invention are all conventional commercially available products without special regulations; the methods used are all conventional methods without special regulations.

[0039] (1) Method for green, rapid, efficient and low-cost synthesis of KA oil

[0040] Example 1

[0041] A method for green, rapid, efficient and low-cost synthesis of KA oil, comprising the following steps:

[0042] (1) Dissolve cyclohexane and hydrogen peroxide in acetonitrile-water to obtain a reaction solution;

[0043] Among them, the molar ratio of cyclohexane to hydrogen peroxide is 1:5 - 1:50, the volume fraction of acetonitrile in the total volume of the reaction solution is 20% - 90%, and the volume fraction of water in the total volume of the reaction solution is 10% - 80%;

[0044] Furthermore, the reaction solution further includes hydrochloric acid, and the molar ratio of hydrochloric acid to hydrogen peroxide is 0.01:1 - 5:1.

[0045] (2) Perform ultrasonic atomization on the reaction solution to form micro-droplets, then condense the micro-droplets. Wait for the micro-droplets to fall back into the reaction solution again, and continue to form micro-droplets through ultrasonic atomization. Perform cyclic ultrasonic atomization-condensation operation to obtain KA oil;

[0046] Among them, both ultrasonic atomization and condensation are carried out at normal temperature and pressure, the frequency of ultrasonic atomization is 1 - 10 Hz, and the total time of the cyclic ultrasonic atomization-condensation operation is 5 - 80 min.

[0047] (2) Device for green, rapid, efficient and low-cost synthesis of KA oil

[0048] Example 2

[0049] Please refer to Figure 1 - Figure 2 , a device for synthesizing KA oil in a green, fast, efficient and low-cost manner, using the method for synthesizing KA oil in a green, fast, efficient and low-cost manner of Example 1, including an ultrasonic atomizer 1. A reaction cavity 2 is provided at the top of the ultrasonic atomizer 1. A reaction chamber 201 is provided inside the reaction cavity 2. An ultrasonic atomization sheet 101 is provided on the ultrasonic atomizer 1. The ultrasonic atomization sheet 101 is communicated with the reaction chamber 201. A condensation sheet 3 is provided at the top of the reaction chamber 201.

[0050] Specifically, please refer to Figure 1 - Figure 2 , the whole reaction device is made of 316L stainless steel, which is strong and durable. The reaction device can also be made of other types of materials, depending on the specific working conditions.

[0051] Sealing rings 6 are provided between the ultrasonic atomizer 1 and the reaction cavity 2, and between the condensation sheet 3 and the reaction cavity 2. The sealing ring 6 makes the airtightness of the whole reaction device good. Even if a gas reaction occurs, it can prevent the leakage of raw materials, avoid material loss and possible safety hazards. At the same time, it also prevents impurities such as moisture and oxygen in the outside world from entering the reaction device, reduces the occurrence of side reactions, and ensures the reaction rate and reaction equilibrium.

[0052] A fixed cover 5 is provided at the top of the condensation sheet 3. The fixed cover 5 is detachably connected to the reaction cavity 2. The addition of the reaction liquid and the extraction of the reaction product are realized through the fixed cover 5.

[0053] The height between the ultrasonic atomization sheet 101 and the condensation sheet 3 is 6-10 cm. This size can ensure that the reaction efficiency of the oxidation reaction reaches the maximum.

[0054] A fixed base 4 is provided at the bottom of the ultrasonic atomizer 1. A fixing hole 401 is provided on the fixed base 4. The fixed base 4 and the fixing hole 401 are used to fix the whole reaction device.

[0055] Furthermore, the condensation sheet 3 can be a quartz glass sheet or other types of condensation sheets, as long as it has the function of condensation, depending on the specific working conditions. Setting the condensation sheet 3 as a quartz glass sheet can apply ultraviolet light to the reaction chamber 201 through the quartz glass sheet according to needs for photocatalysis, and can meet the needs of various organic synthesis reactions.

[0056] Furthermore, a plurality of gas channels 202 are provided on the reaction cavity 2. The gas channels 202 are communicated with the reaction chamber 201. By providing the gas channels 202, various reaction gases can be introduced into the reaction chamber 201 through the gas channels 202 according to needs, and the reaction requirements of various gas atmospheres can be met.

[0057] Please refer toFigure 1 - Figure 2 For the above-mentioned device for synthesizing KA oil with green, fast, efficient and low cost, the usage method includes the following steps:

[0058] (1) Dissolve cyclohexane and hydrogen peroxide in acetonitrile-water to obtain a reaction solution;

[0059] Among them, the molar ratio of cyclohexane to hydrogen peroxide is 1:5 - 1:50, the volume fraction of acetonitrile in the total volume of the reaction solution is 20 - 90%, and the volume fraction of water in the total volume of the reaction solution is 10% - 80%;

[0060] Furthermore, the reaction solution also includes hydrochloric acid, and the molar ratio of hydrochloric acid to hydrogen peroxide is 0.01:1 - 5:1.

[0061] (2) Open the fixed cover 5, remove the condensation sheet 3, add the reaction solution into the reaction chamber 201, make the reaction solution contact the ultrasonic atomization sheet 101, and then install the condensation sheet 3 and the fixed cover 5.

[0062] (3) Connect the ultrasonic atomizer 1 to the power supply, start the ultrasonic atomizer 1, and the ultrasonic atomization sheet 101 performs ultrasonic atomization on the reaction solution to form micro-droplets; during the ultrasonic atomization process, the micro-droplets rise, reach the top of the reaction chamber 201 and contact the condensation sheet 3 to be condensed, and the condensed micro-droplets fall back. When the micro-droplets fall back into the reaction solution again and contact the ultrasonic atomization sheet 101, they continue to form micro-droplets through ultrasonic atomization, and perform cyclic ultrasonic atomization - condensation operation to obtain KA oil;

[0063] Among them, both ultrasonic atomization and condensation are carried out at normal temperature and pressure, the frequency of ultrasonic atomization is 1 - 10 Hz, and the total time of the ultrasonic atomization - condensation cyclic operation is 5 - 80 min.

[0064] (III) Effects of the method and device for synthesizing KA oil

[0065] Example 3

[0066] (1) Mix 45.33 mg of 30% hydrogen peroxide aqueous solution and 1.6 g of water to prepare 1645.33 mg of 0.83% hydrogen peroxide aqueous solution;

[0067] Add 3.4 mg (0.04 mmol) of cyclohexane and 1645.33 mg (0.40 mmol) of 0.83% hydrogen peroxide aqueous solution (the molar ratio of cyclohexane to hydrogen peroxide is 1:10) into 1.89 g of acetonitrile (the volume fraction of acetonitrile is 60% and the volume fraction of water is 40%), and dissolve them fully to obtain a reaction solution.

[0068] (2) Open the fixed cover 5, remove the condensation sheet 3, add 4 mL of the reaction solution into the reaction chamber 201 with a height of 6 cm. The reaction solution contacts the ultrasonic atomization sheet 101, and then install the condensation sheet 3 and the fixed cover 5.

[0069] (3) Connect the ultrasonic atomizer 1 to the power supply and start the ultrasonic atomizer 1. Under normal temperature and pressure, use the ultrasonic atomization sheet 101 with a frequency of 2.4 Hz to ultrasonically atomize the reaction solution to form micro-droplets; during the ultrasonic atomization process, the micro-droplets rise, reach the top of the reaction chamber 201 and contact the condensation sheet 3 and then are condensed. The condensed micro-droplets fall back. When the micro-droplets fall back into the reaction solution again and contact the ultrasonic atomization sheet 101, they continue to form micro-droplets through ultrasonic atomization, and perform the cyclic ultrasonic atomization-condensation operation; after 5 minutes of cycling, the reaction stops, and KA oil is obtained. Use gas chromatography to detect the KA oil, and its yield is measured to be 1.47%.

[0070] Example 4

[0071] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after cycling for 10 minutes, and the remaining operations are the same. KA oil is obtained, and its yield is 2.04%.

[0072] Example 5

[0073] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after cycling for 20 minutes, and the remaining operations are the same. KA oil is obtained, and its yield is 5.13%.

[0074] Example 6

[0075] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after cycling for 30 minutes, and the remaining operations are the same. KA oil is obtained, and its yield is 5.52%.

[0076] Example 7

[0077] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after cycling for 40 minutes, and the remaining operations are the same. KA oil is obtained, and its yield is 5.62%.

[0078] Example 8

[0079] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after cycling for 50 minutes, and the remaining operations are the same. KA oil is obtained, and its yield is 5.67%.

[0080] Example 9

[0081] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after cycling for 60 minutes, and the remaining operations are the same. KA oil is obtained, and its yield is 5.40%.

[0082] Example 10

[0083] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after 70 minutes of cycling, and the rest of the operations are the same, obtaining KA oil with a yield of 5.50%.

[0084] Example 11

[0085] The difference between this implementation method and Example 3 is that in step (3), the reaction stops after 80 minutes of cycling, and the rest of the operations are the same, obtaining KA oil with a yield of 5.40%.

[0086] Example 12

[0087] The difference between this implementation method and Example 7 is that in step (1), the volume fraction of acetonitrile is 20% and the volume fraction of water is 80%, and the rest of the operations are the same, obtaining KA oil with a yield of 0.60%.

[0088] Example 13

[0089] The difference between this implementation method and Example 7 is that in step (1), the volume fraction of acetonitrile is 40% and the volume fraction of water is 60%, and the rest of the operations are the same, obtaining KA oil with a yield of 1.98%.

[0090] Example 14

[0091] The difference between this implementation method and Example 7 is that in step (1), the volume fraction of acetonitrile is 80% and the volume fraction of water is 20%, and the rest of the operations are the same, obtaining KA oil with a yield of 3.20%.

[0092] Example 15

[0093] The difference between this implementation method and Example 7 is that in step (1), the volume fraction of acetonitrile is 90% and the volume fraction of water is 10%, and the rest of the operations are the same, obtaining KA oil with a yield of 1.46%.

[0094] Example 16

[0095] The difference between this implementation method and Example 7 is that in step (1), the molar ratio of cyclohexane to hydrogen peroxide is 1:5, and the rest of the operations are the same, obtaining KA oil with a yield of 0.90%.

[0096] Example 17

[0097] The difference between this implementation method and Example 7 is that in step (1), the molar ratio of cyclohexane to hydrogen peroxide is 1:15, and the rest of the operations are the same, obtaining KA oil with a yield of 5.35%.

[0098] Example 18

[0099] The difference between this implementation method and Example 7 is that in step (1), the molar ratio of cyclohexane to hydrogen peroxide is 1:20, and the remaining operations are the same. KA oil is obtained, and its yield is 3.73%.

[0100] Example 19

[0101] The difference between this implementation method and Example 7 is that in step (1), the molar ratio of cyclohexane to hydrogen peroxide is 1:50, and the remaining operations are the same. KA oil is obtained, and its yield is 3.74%.

[0102] To more intuitively compare the influence of the process parameters of Examples 3 - 19 on the yield of KA oil, Table 1 is formed as follows.

[0103] Table 1 Influence of the process parameters of Examples 3 - 19 on the yield of KA oil

[0104]

[0105] As can be seen from Table 1:

[0106] Comparing Examples 3 - 11, it can be seen that as the total time of the ultrasonic atomization - condensation operation extends from 5 min to 40 min, the yield of KA oil gradually increases. When the total time of the ultrasonic atomization - condensation operation extends from 40 min to 80 min, the increase in the yield of KA oil is not obvious, and too long a time will even cause the yield of KA oil to decrease significantly. Therefore, considering that extending the reaction time will increase costs, the total time of the ultrasonic atomization - condensation cycle operation is preferably 40 min.

[0107] Comparing Examples 7, 12 - 15, it can be seen that as the volume fraction of acetonitrile increases from 20% to 60%, the yield of KA oil gradually increases. When the volume fraction of acetonitrile increases from 60% to 90%, the yield of KA oil decreases significantly. Therefore, the volume fraction of acetonitrile is preferably 60%.

[0108] Comparing Examples 7, 16 - 19, it can be seen that as the molar ratio of cyclohexane to hydrogen peroxide increases from 1:5 to 1:10, the yield of KA oil gradually increases. When the molar ratio of cyclohexane to hydrogen peroxide increases from 1:10 to 1:50, the yield of KA oil decreases significantly. Therefore, the molar ratio of cyclohexane to hydrogen peroxide is preferably 1:10.

[0109] In summary, the preferred reaction conditions for KA oil are as follows: the molar ratio of cyclohexane to hydrogen peroxide is 1:10, the volume fraction of acetonitrile is 60%, the volume fraction of water is 40%, and the total time of the ultrasonic atomization - condensation cycle operation is 40 min. Under the preferred reaction conditions, the yield of KA oil is as high as 5.62%.

[0110] The product prepared in Example 7 was tested, and its mass spectrum and secondary mass spectrum are respectively as Figure 3 - Figure 4 shown.

[0111] The Figure 3 - Figure 4 mass spectrum and secondary mass spectrum of the product shown were compared with the mass spectrum and secondary mass spectrum of the cyclohexanol standard and cyclohexanone standard shown in Figure 5 - Figure 8 . It can be seen that the main molecular ion peaks of the product are consistent with those of the standard. Thus, it can be inferred that the product prepared in Example 7 is KA oil.

[0112] (IV) Effects of the method and device for synthesizing KA oil when adding hydrochloric acid as a promoter

[0113] Example 20

[0114] The difference between this implementation method and Example 7 is that

[0115] in step (1), 45.33 mg of 30% hydrogen peroxide aqueous solution and 1.55 g of water were mixed, and then 50.7 mg of 36% concentrated hydrochloric acid was added. After mixing evenly, 1646.03 mg of 0.83% acidic hydrogen peroxide aqueous solution was prepared;

[0116] 3.4 mg (0.04 mmol) of cyclohexane and 1645.33 mg (0.40 mmol) of 0.83% acidic hydrogen peroxide aqueous solution (the molar ratio of cyclohexane to hydrogen peroxide is 1:10, and the molar ratio of hydrochloric acid to hydrogen peroxide is 1:1) were added to 1.89 g of acetonitrile (the volume fraction of acetonitrile is 60%, and the volume fraction of water is 40%), and fully dissolved to obtain a reaction solution;

[0117] The remaining operations were the same, and KA oil was obtained with a yield of 16.10%.

[0118] Example 21

[0119] The difference between this implementation method and Example 20 is that in step (1), the molar ratio of hydrochloric acid to hydrogen peroxide is 0.01:1. The remaining operations were the same, and KA oil was obtained with a yield of 7.70%.

[0120] Example 22

[0121] The difference between this implementation method and Example 20 is that in step (1), the molar ratio of hydrochloric acid to hydrogen peroxide is 0.1:1. The remaining operations were the same, and KA oil was obtained with a yield of 10.47%.

[0122] Example 23

[0123] The difference between this implementation method and Example 20 is that in step (1), the molar ratio of hydrochloric acid to hydrogen peroxide is 5:1, and the rest of the operations are the same, obtaining KA oil with a yield of 8.58%.

[0124] To more intuitively compare the influence of the process parameters of Examples 7, 20 - 23 on the yield of KA oil, Table 2 is formed as follows.

[0125] Table 2 Influence of the process parameters of Examples 7, 20 - 23 on the yield of KA oil

[0126]

[0127] As can be seen from Table 2:

[0128] Comparing Examples 7 and 20, it can be seen that after adding hydrochloric acid, the yield of KA oil has increased significantly. This shows that the addition of hydrochloric acid is beneficial to the progress of the oxidation reaction. This is mainly because hydrogen peroxide will decompose under alkaline conditions. After adding hydrochloric acid, hydrogen ions will inhibit the decomposition of hydrogen peroxide, promote the generation of more hydroxyl radicals by hydrogen peroxide, promote the progress of the forward reaction, improve the reaction rate and selectivity of the oxidation reaction, and thus increase the yield of KA oil.

[0129] Comparing Examples 20 - 23, it can be seen that as the molar ratio of hydrochloric acid to hydrogen peroxide increases from 0.01:1 to 1:1, the yield of KA oil gradually increases. When the molar ratio of hydrochloric acid to hydrogen peroxide increases from 1:1 to 5:1, the yield of KA oil decreases significantly. Therefore, the preferred molar ratio of hydrochloric acid to hydrogen peroxide is 1:1.

[0130] In summary, when adding hydrochloric acid as a promoter, the preferred reaction conditions for KA oil are as follows: the molar ratio of cyclohexane to hydrogen peroxide is 1:10, the volume fraction of acetonitrile is 60%, the volume fraction of water is 40%, the molar ratio of hydrochloric acid to hydrogen peroxide is 1:1, and the total time of ultrasonic atomization - condensation cycle operation is 40 min. Under the preferred reaction conditions, the yield of KA oil is as high as 16.10%.

[0131] It should be noted that in the above Examples 3-23, in step (2), adding 4 mL of the reaction solution into the reaction chamber 201 is only a preferred embodiment. In actual production, it can be adjusted adaptively according to specific circumstances. In step (2), the height of the reaction chamber 201 is 6 cm, that is, the height between the ultrasonic atomization sheet 101 and the condensation sheet 3 is 6 cm. This is only a preferred embodiment. In actual production, the height between the ultrasonic atomization sheet 101 and the condensation sheet 3 can be 6-10 cm and can be adjusted adaptively according to specific circumstances. In step (3), the frequency of the ultrasonic atomization sheet 101 is 2.4 Hz. This is only a preferred embodiment. In actual production, the frequency of the ultrasonic atomization sheet 101 can be 1-10 Hz and can be adjusted adaptively according to specific circumstances.

[0132] The present invention provides a method for synthesizing KA oil in a green, rapid, efficient and low-cost manner. Using cyclohexane as a raw material, hydrogen peroxide as a green oxidant, and acetonitrile-water as a solvent, under the action of ultrasonic atomization, the reaction solution is "fragmented" into micro-droplets, and an oxidation reaction occurs on the surface of the micro-droplets to generate KA oil. The micro-droplets formed by ultrasonic atomization rise, condense when encountering cold and then fall back, and fall back into the reaction solution to continue to form micro-droplets through ultrasonic atomization. By circulating the ultrasonic atomization-condensation operation, KA oil is continuously generated. The method for synthesizing KA oil in a green, rapid, efficient and low-cost manner of the present invention can also add hydrochloric acid as a promoter to inhibit the decomposition of hydrogen peroxide, promote the generation of more hydroxyl radicals by hydrogen peroxide, promote the progress of the forward reaction, and improve the reaction rate and selectivity of the oxidation reaction. The present invention also provides a device for synthesizing KA oil in a green, rapid, efficient and low-cost manner. Compared with the prior art:

[0133] (1) The present invention utilizes the surface characteristics of micro-droplets, uses micro-droplets as micro-reactors, applies them to the activation reaction of cycloalkanes, and an oxidation reaction occurs on the surface of the micro-droplets to oxidize cyclohexane to generate KA oil. The synthesis method has a rapid reaction, a short reaction time, far faster than the several hours required by the prior art, high selectivity, few by-products, and can be carried out under normal temperature and pressure without high temperature and high pressure. The reaction conditions are mild, the yield is high, and the reaction effect is good, having important industrial value.

[0134] (2) The synthesis method of the present invention does not require any catalyst, reduces the cost brought by the catalyst, and at the same time avoids the resource consumption and possible pollution caused by the synthesis of the catalyst. In addition, the raw materials required for the synthesis method of the present invention are only cyclohexane, the green oxidant hydrogen peroxide and the promoter hydrochloric acid, which are environmentally friendly and green.

[0135] (3) The synthesis method of the present invention can also add hydrochloric acid as a promoter. Hydrogen peroxide will decompose under alkaline conditions. After adding hydrochloric acid, hydrogen ions will inhibit the decomposition of hydrogen peroxide, promote the generation of more hydroxyl radicals by hydrogen peroxide, promote the progress of the forward reaction, increase the reaction rate and selectivity of the oxidation reaction, and improve the effect of the oxidation reaction.

[0136] (4) The reaction device of the present invention is integrally made of 316L stainless steel, which is strong and durable; sealing rings are provided between the ultrasonic nebulizer and the reaction chamber, and between the condenser sheet and the reaction chamber in the reaction device. The airtightness of the entire reaction device is good. Even if a gas reaction occurs, it can prevent the leakage of raw materials, avoid material loss and potential safety hazards. At the same time, it also prevents impurities such as moisture and oxygen in the outside world from entering the reaction device, reduces the occurrence of side reactions, and ensures the reaction rate and reaction equilibrium.

[0137] (5) The reaction device of the present invention can replace the reaction chamber with different sizes according to needs, or replace the ultrasonic nebulizer with different frequencies and different powers to generate micro-droplets with different sizes and different quantities, thereby affecting the reaction time, and reaction kinetics research can be carried out accordingly.

[0138] (6) The reaction device of the present invention can apply ultraviolet light to the reaction chamber through a quartz glass sheet for photocatalysis according to needs, which can meet the requirements of various organic synthesis reactions; in addition, various reaction gases can be introduced into the reaction chamber through the gas channel according to needs, which can meet the reaction requirements of various gas atmospheres. The present invention can be widely applied to the technical field of organic synthesis.

[0139] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A green, fast, efficient and low-cost method for synthesizing KA oil, characterized in that: The following steps are involved: (1) dissolving cyclohexane and hydrogen peroxide in acetonitrile-water to obtain a reaction solution; (2) The reaction liquid is ultrasonically atomized to form micro-droplets, which are then condensed. The micro-droplets fall back into the reaction liquid again, and continue to be ultrasonically atomized to form micro-droplets. The ultrasonic atomization-condensation operation is repeated to obtain KA oil.

2. The green, fast, efficient and low-cost method for synthesizing KA oil according to claim 1, characterized in that: In step (1), the molar ratio of cyclohexane to hydrogen peroxide is 1:5-1:50, the volume fraction of acetonitrile to the total volume of the reaction solution is 20-90%, and the volume fraction of water to the total volume of the reaction solution is 10%-80%.

3. The green, fast, efficient and low-cost method for synthesizing KA oil according to claim 1, characterized in that: In step (2), ultrasonic atomization and condensation are both carried out at room temperature and pressure, the frequency of ultrasonic atomization is 1-10 Hz, and the total time of ultrasonic atomization-condensation cycle operation is 5-80 min.

4. The green, fast, efficient and low-cost method for synthesizing KA oil according to claim 1, characterized in that: In step (1), the reaction solution also includes hydrochloric acid, and the molar ratio of hydrochloric acid to hydrogen peroxide is 0.01:1-5:

1.

5. A device for synthesizing KA oil in a green, fast, efficient and low-cost manner, using the method for synthesizing KA oil in a green, fast, efficient and low-cost manner as described in any one of claims 1 to 4, characterized in that: It comprises an ultrasonic atomizer, a reaction cavity is arranged at the top of the ultrasonic atomizer, a reaction cavity is arranged inside the reaction cavity, an ultrasonic atomizer is provided with an ultrasonic atomizing sheet, the ultrasonic atomizing sheet is communicated with the reaction cavity, and a condensing sheet is arranged at the top of the reaction cavity.

6. The green, fast, efficient and low-cost KA oil synthesis device according to claim 5 is characterized in that: The condensing sheet comprises a quartz glass sheet; sealing rings are arranged between the ultrasonic atomizer and the reaction chamber, and between the condensing sheet and the reaction chamber.

7. The green, fast, efficient and low-cost KA oil synthesis device according to claim 5 is characterized in that: A fixing cover is provided at the top of the condensing sheet, and the fixing cover is detachably connected to the reaction chamber; a fixing base is provided at the bottom of the ultrasonic atomizer, and a fixing hole is provided on the fixing base.

8. The green, fast, efficient and low-cost KA oil synthesis device according to claim 5 is characterized in that: The height between the ultrasonic atomization sheet and the condensation sheet is 6-10 cm.

9. The green, fast, efficient and low-cost KA oil synthesis device according to claim 5, characterized in that: The reaction chamber is provided with a plurality of gas channels, and the gas channels are communicated with the reaction chamber.

10. The green, fast, efficient and low-cost KA oil synthesis device according to claim 5, characterized in that: The method of use includes the following steps: (1) Open the fixed cover, remove the condensing sheet, add the reaction liquid into the reaction chamber, the reaction liquid contacts the ultrasonic atomizing sheet, and then install the condensing sheet and the fixed cover; (2) Connecting the ultrasonic atomizer to a power source and starting the ultrasonic atomizer, the ultrasonic atomizer plate ultrasonically atomizes the reaction liquid to form micro-droplets; during the ultrasonic atomization process, the micro-droplets rise, reach the top of the reaction chamber, and are condensed after contacting the condensation plate. The condensed micro-droplets fall back, and the micro-droplets fall back into the reaction liquid again, and continue to form micro-droplets through ultrasonic atomization after contacting the ultrasonic atomization plate, and the ultrasonic atomization-condensation operation is cyclically performed to obtain KA oil.

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