System and method for preparing anhydrous peroxy acid with carbon number of more than C3 by coupling resin bed with NaA membrane module

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a system and a method for preparing anhydrous peroxy acid with more than C3 by coupling a resin bed with a NaA membrane module. The system comprises a reactive distillation tower, the reactive distillation tower is sequentially provided with a tower top area, a first structured packing layer, a plurality of reaction separation assemblies and a tower bottom area from top to bottom, and each reaction separation assembly comprises an acidic resin bed and a NaA molecular sieve membrane assembly located below the acidic resin bed. The first structured packing layer is provided with a mixed material inlet of organic acid with more than C3 and hydrogen peroxide, and the acidic resin bed is provided with an organic solvent inlet. By adopting the system to prepare anhydrous peroxy acid, the energy consumption of the reaction rectifying tower can be effectively reduced, the reaction speed can be increased, decomposition explosion of peroxide can be prevented, meanwhile, loss of a catalyst in the later period can be effectively avoided, the catalyst is prevented from entering the anhydrous peroxy acid product, caprolactone is prepared by utilizing the prepared anhydrous peroxy acid product, and the yield of caprolactone is improved. And relatively high caprolactone selectivity and yield can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and in particular to a system and method for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane component, and in particular to a system and method for preparing anhydrous peroxyacids above C3 by coupling a reaction distillation tower with an acidic resin bed with a NaA molecular sieve membrane component. Background Art

[0002] Peroxyacid is the key raw material for oxidizing cyclohexanone to produce caprolactone. The current method mainly uses the reaction of hydrogen peroxide and propionic acid, and water is generated during the reaction process. In addition, if the reaction temperature cannot be strictly controlled during the reaction, the peroxide will decompose and explode. Although traditional reactive distillation can improve the conversion efficiency, if the water content of peroxypropionic acid is reduced to the ppm level, more plates and a larger reflux ratio are required, and the residence time of the peroxide in the tower will also increase relatively, which will cause the peroxide to decompose and explode.

[0003] CN102584775B and CN103570667B mention the production of peroxycarboxylic acid by reactive distillation. Although this operation mode can overcome the disadvantages of intermittent operation and produce peroxyacid, when producing anhydrous peroxyacid by reactive distillation, the water content requirement is too high, resulting in a long residence time of peroxide, decomposition and explosion, and the problem of high energy consumption in obtaining anhydrous peroxyacid is not solved. The slow heating and backpack reactive distillation methods proposed by CN202010904713.6, CN202010904726.3 and CN202010904683.9 can solve the problem of long residence time or local high temperature explosion, but cannot solve the problem of high energy consumption when obtaining anhydrous peroxyacid, and the catalyst used is a soluble catalyst, which will cause catalyst loss. Summary of the invention

[0004] The purpose of the present invention is to solve the problems that the prior art cannot simultaneously solve the problems of long peroxide residence time leading to decomposition and explosion of peroxide, as well as low reaction speed, high energy consumption and easy loss of catalyst in the reaction process when preparing anhydrous peroxyacid, and thus propose a system and method for preparing anhydrous peroxyacid above C3 by coupling a resin bed with a NaA membrane assembly. The system can reduce the number of theoretical plates in the reaction distillation tower by coupling the NaA membrane assembly to a reaction distillation tower, effectively reduce the energy consumption of the reaction distillation tower, and can also separate water from other substances in time during the reaction process, reduce the back mixing between the reaction raw materials, thereby accelerating the reaction speed, reducing the reaction residence time, and effectively preventing the decomposition and explosion of peroxide. At the same time, the reaction distillation tower also includes an acidic resin bed arranged in sequence with the NaA membrane assembly, and the acidic resin bed and the reaction raw materials and the reaction products are all in a heterogeneous operation, which can effectively avoid the loss of the catalyst in the later stage.

[0005] The first aspect of the present invention provides a system for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane assembly. The system comprises a reaction distillation tower, wherein the reaction distillation tower is provided with a top zone, a first structured packing layer, a plurality of reaction separation assemblies and a bottom zone in sequence from top to bottom. The reaction separation assembly comprises an acidic resin bed and a NaA molecular sieve membrane assembly located below the acidic resin bed. The first structured packing layer has an inlet for a mixture of an organic acid above C3 and hydrogen peroxide, and the acidic resin bed has an inlet for an organic solvent.

[0006] Preferably, the total height of the acidic resin bed is 10-30% of the height of the reactive distillation tower.

[0007] Preferably, the number of the reaction separation components is 2-4.

[0008] Preferably, the acidic resin bed also has a hydrogen peroxide inlet.

[0009] Preferably, the NaA molecular sieve membrane assembly has a first water outlet.

[0010] Preferably, the system further comprises a condenser and a phase separator, and the tower top zone is sequentially connected to the condenser and the phase separator via a connecting pipe. More preferably, the phase separator has a second water outlet.

[0011] Preferably, the organic solvent inlet is communicated with the phase separator, and is used to transport the organic solvent output from the phase separator to the acidic resin bed.

[0012] Preferably, the system further comprises a second structured packing layer, the bottom of which is connected to the tower bottom zone.

[0013] Preferably, the system further comprises a reboiler and an anhydrous peroxyacid receiving tank, and the tower bottom zone is sequentially connected to the reboiler and the anhydrous peroxyacid receiving tank via a connecting pipe.

[0014] The second aspect of the present invention provides a method for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane assembly. The method is implemented in the above-mentioned system, and the method comprises: transporting an organic acid above C3 and hydrogen peroxide to the first structured packing layer, and then entering the acidic resin bed for reaction, the reaction product is separated by the NaA molecular sieve membrane assembly, the separated anhydrous peroxyacid solution enters the bottom zone of the tower, the separated water forms an azeotropic mixture with the organic solvent transported to the acidic resin bed through the organic solvent inlet, and the azeotropic mixture enters the top zone of the tower.

[0015] Preferably, the weight ratio of the C3 or higher organic acid to the hydrogen peroxide is 1-4:1; more preferably, the weight ratio of the C3 or higher organic acid to the hydrogen peroxide is 2-3:1.

[0016] Preferably, the concentration of the hydrogen peroxide is 30-70% by weight.

[0017] Preferably, the feed conditions of the C3 or higher organic acid and hydrogen peroxide include: a feed temperature of 20-40° C. and a feed flow rate of 2-5 kg / h.

[0018] Preferably, the temperature of the tower bottom zone is 60-70°C.

[0019] Preferably, the reaction conditions include: temperature of 40-80° C. and pressure of 5-20 KPa.

[0020] Preferably, the C3 or higher organic acid is propionic acid and / or butyric acid.

[0021] Preferably, the organic solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, methylene chloride and acetonitrile.

[0022] In the system for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane assembly described in the present invention, by coupling the NaA membrane assembly to a reaction distillation tower, the number of theoretical plates in the reaction distillation tower can be reduced, the energy consumption of the reaction distillation tower can be effectively reduced, and water can be separated from other substances in a timely manner during the reaction process, thereby reducing back mixing between the reaction raw materials, thereby accelerating the reaction speed and reducing the reaction residence time. At the same time, the decomposition and explosion of peroxides are prevented. At the same time, an acidic resin bed connected to the NaA membrane assembly is also arranged in the reaction distillation tower. The acidic resin bed contains a catalyst that reacts with an organic acid and hydrogen peroxide to generate peroxy acid. On the one hand, the acidic resin bed and the reaction raw materials and the reaction products are all operated in a heterogeneous phase, which can effectively avoid the loss of the catalyst in the later stage. On the other hand, the catalyst in the acidic resin bed will not enter the top area or the bottom area of ​​the tower with the azeotropic mixture or the anhydrous peroxy acid product, which can effectively avoid the doping of the catalyst in the finally obtained anhydrous peroxy acid product. Therefore, when the obtained anhydrous peroxy acid product is used to oxidize cyclohexanone to prepare caprolactone, it will not cause the caprolactone to undergo a polycondensation reaction, thereby improving the selectivity and yield of caprolactone. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a system for preparing anhydrous peroxypropionic acid by coupling a resin bed with a NaA membrane assembly according to the present invention.

[0024] Description of Reference Numerals

[0025] 1. Inlet for the mixture of organic acid above C3 and hydrogen peroxide; 2. NaA molecular sieve membrane assembly; 3. Inlet for hydrogen peroxide; 4. Inlet for organic solvent; 5. Condenser; 6. First structured packing layer; 7. Acid resin bed; 8. First water outlet; 9. Connecting pipe; 10. Phase separator; 11. Second water outlet; 12. Tower top area; 13. Second structured packing layer; 14. Tower bottom area; 15. Reboiler; 16. Anhydrous peracid receiving tank. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, unless otherwise specified, features defined as "first" and "second" may explicitly or implicitly include one or more of the features; "plurality" means two or more. The term "including" and any variation thereof means non-exclusive inclusion, and one or more other features, integers, steps, operations, units, components and / or combinations thereof may exist or be added.

[0029] In addition, terms indicating orientation or positional relationships such as "upper", "lower", "inside", and "outside" are described based on the orientation or relative positional relationships shown in the drawings, and are only for the convenience of describing the simplified description of the present application, and do not indicate that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0030] In addition, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internally connected between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] The first aspect of the present invention provides a system for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane module, such as Figure 1 As shown, the system includes a reaction distillation tower, which is provided with a top zone 12, a first structured packing layer 6, a plurality of reaction separation components and a bottom zone 14 in sequence from top to bottom. The reaction separation component includes an acid resin bed 7 and a NaA molecular sieve membrane component 2 located below the acid resin bed 7. The first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acid resin bed 7 has an organic solvent inlet 4.

[0032] In the system of the present invention, in a specific implementation, the reaction distillation tower can be a conventional choice in the art, and specifically, the tower body of the reaction distillation tower has a height of 3-5 m.

[0033] In the system of the present invention, in a specific embodiment, the first structured packing layer 6 has a mixed material inlet 1 for organic acids with C3 or more and hydrogen peroxide, and the mixed material inlet 1 for organic acids with C3 or more and hydrogen peroxide is connected to a raw material feed pipe. In a specific implementation process, organic acids with C3 or more and hydrogen peroxide are transported by the raw material feed pipe and transported to the first structured packing layer 6 through the mixed material inlet 1 for organic acids with C3 or more and hydrogen peroxide.

[0034] In the system of the present invention, in a specific embodiment, the filler in the first structured packing layer 6 is selected from one or more of wire mesh corrugated packing, mesh corrugated packing and plate hole corrugated packing. In a preferred embodiment, the packing height of the first structured packing layer 6 is 0.5-1.0m.

[0035] In the system described in the present invention, the acidic resin bed 7 and the NaA molecular sieve membrane assembly 2 are interconnected, so that when the organic acid and hydrogen peroxide generate peracid, the water generated by the reaction can be removed in time, which is beneficial to the reaction, while avoiding the explosion of peroxide and reducing the loss of the later catalyst. In a specific embodiment, the acidic resin bed 7 is connected to the bottom of the first structured packing layer 6, and the acidic resin bed 7 is connected to the top of the NaA molecular sieve membrane assembly 2.

[0036] In the system of the present invention, in a specific embodiment, the acidic resin bed 7 comprises an acidic ion exchange resin. In a preferred embodiment, the acidic ion exchange resin is selected from one or more of Amberlyst series ion exchange resins, Amberlyst IR-120 ion exchange resins and 732 type styrene strong acid cation exchange resins.

[0037] In the system of the present invention, in a specific embodiment, the total height of the acidic resin bed 7 is 10-30% of the height of the reactive distillation column. In a preferred embodiment, the total height of the acidic resin bed 7 is 30-80% of the total height of the first structured packing layer and the second structured packing layer.

[0038] In the system of the present invention, in order to remove the water in the hydrogen peroxide in time, increase the concentration of the hydrogen peroxide, and thus accelerate the reaction speed, in a specific embodiment, the acidic resin bed 7 has an organic solvent inlet 4. In a preferred embodiment, the organic solvent inlet 4 is connected to an organic solvent feed pipe. In the specific implementation process, the organic solvent is transported by the organic solvent feed pipe and enters the acidic resin bed 7 through the organic solvent inlet 4. The organic solvent entering the acidic resin bed 7 forms an azeotropic mixture with the water therein, and then enters the tower top zone 12.

[0039] In the system of the present invention, in a specific embodiment, the NaA molecular sieve membrane assembly 2 includes a NaA molecular sieve membrane. In this article, the source of the NaA molecular sieve membrane is not limited, and it can be purchased or prepared by a method in the prior art. In a preferred embodiment, the NaA molecular sieve membrane assembly adopts a tubular form, specifically, the NaA molecular sieve membrane assembly has 10-20 tubes.

[0040] In the system of the present invention, in order to remove the water generated by the reaction and the residual water in the hydrogen peroxide in time, in a specific embodiment, the NaA molecular sieve membrane assembly 2 has a first water outlet 8. In the specific implementation process, since the water seepage side pressure of the NaA molecular sieve membrane assembly is lower than the distillation tower pressure, the water is extracted through the first water outlet 8 after being precipitated from the NaA molecular sieve membrane assembly.

[0041] In the system of the present invention, in order to reduce the energy consumption of the reaction distillation column, speed up the reaction speed and improve the product quality, the conversion rate of hydrogen peroxide is greater than 97%, the selectivity of peroxyacid is greater than 97%, the concentration of peroxyacid is 5-50% by weight, and the water content is less than 100 ppm, in a preferred embodiment, the number of the reaction separation components is 2-4, for example, 2, 3 or 4. In a more preferred embodiment, the number of the reaction separation components is 3.

[0042] In the system of the present invention, when the number of the reaction separation components is 2-4, in order to speed up the reaction speed, it is necessary to replenish the consumed hydrogen peroxide in time. In a specific embodiment, the acidic resin bed 7 also has a hydrogen peroxide inlet 3. In a preferred embodiment, the hydrogen peroxide inlet 3 is connected to the hydrogen peroxide feed pipe, and in the actual operation process, the hydrogen peroxide can be more conveniently transported to the acidic resin bed 7. In a more preferred embodiment, when the number of the reaction separation components is 3, from top to bottom, the feed temperature of the hydrogen peroxide inlet 3 in the second acidic resin bed 7 is 40-50°C, preferably 45°C, and the feed temperature of the hydrogen peroxide inlet 3 in the third acidic resin bed 7 is 50-60°C, preferably 55°C. In a further preferred embodiment, the feed flow rates of the hydrogen peroxide inlets 3 in the second acidic resin bed 7 and the third acidic resin bed 7 are both 1 / 3 of the feed flow rate in the mixed material inlet 1 of the organic acid and hydrogen peroxide.

[0043] In the system of the present invention, in order to recycle the azeotropic mixture formed in the acidic resin bed 7, in a specific embodiment, the system further includes a condenser 5 and a phase separator 10, and the tower top zone 12 is sequentially connected to the condenser 5 and the phase separator 10 through a connecting pipe. In the specific implementation process, the azeotropic mixture is sequentially condensed in the condenser 5 through the tower top zone 12, and then phase-separated in the phase separator 10, the upper layer is the solvent phase, and the lower layer is the water phase. Specifically, the phase separator 10 has a second water outlet 11, and the water phase is discharged through the second water outlet 11.

[0044] In the system of the present invention, in a preferred embodiment, the organic solvent inlet 4 is connected to the phase separator 10, and is used to transport the organic solvent output by the phase separator 10 to the acidic resin bed 7 for recycling. In the specific operation process, when the number of the reaction separation components is 2-4, the organic solvent inlet 4 is connected to the connecting pipe 9, and is used to transport the organic solvent output by the phase separator 10 to each acidic resin bed 7.

[0045] In the system of the present invention, in a specific embodiment, the system further comprises a second structured packing layer 13, the bottom of which is connected to the tower bottom zone 14. In a preferred embodiment, the packing in the second structured packing layer 13 is selected from one or more of wire mesh corrugated packing, mesh corrugated packing and plate hole corrugated packing. In a more preferred embodiment, the packing height of the second structured packing layer 13 is 0.5-1.0 m.

[0046] In the system of the present invention, in a specific embodiment, the system further comprises a reboiler 15 and an anhydrous peroxyacid receiving tank 16, and the tower bottom zone 14 is sequentially connected to the reboiler 15 and the anhydrous peroxyacid receiving tank 16 through a connecting pipe. In a specific operation process, the peroxyacid product in the tower bottom zone 14 is extracted from the liquid through the reboiler 15, the reboil ratio is 3-5:1, and is stored in the anhydrous peroxyacid receiving tank 16, specifically, the storage temperature is 0°C.

[0047] In the system of the present invention, in a specific operation process, the organic acid with C3 or more and hydrogen peroxide are transported by the raw material feed pipe, and enter the first structured packing layer 6 through the mixed material inlet 1 of the organic acid with C3 or more and hydrogen peroxide. The organic acid with C3 or more and hydrogen peroxide undergo autocatalytic reaction and dehydration separation in the first structured packing layer 6, and then enter the acid resin bed 7. At the same time, the organic solvent is transported by the organic solvent feed pipe and enters the acid resin bed 7 through the organic solvent inlet 4. During the reaction process, the product obtained by the reaction of the organic acid with C3 or more and hydrogen peroxide passes through the organic solvent inlet 4. The NaA molecular sieve membrane assembly 2 is used for separation, and the separated anhydrous peroxy acid solution continues to flow downward into the next acidic resin bed 7, and hydrogen peroxide is added to the acidic resin bed 7 through the hydrogen peroxide inlet 3 to continue the next round of reaction; part of the separated water is discharged through the first water outlet 8, and the other part of the separated water and the residual water in the hydrogen peroxide form an azeotropic mixture with the organic solvent and enter the top area 12, and are condensed in the condenser 5, and then phase separation is carried out in the phase separator 10, the water phase is discharged from the second water outlet 11, and the organic solvent enters the acidic resin bed 7 through the organic solvent inlet 4 for recycling.

[0048] According to a first embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 includes a reaction distillation tower, which is sequentially provided with a top zone 12, a first structured packing layer 6, a plurality of reaction separation components and a bottom zone 14 from top to bottom, wherein the reaction separation component includes an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, the first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4.

[0049] According to a second embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 includes a reaction distillation tower, which is sequentially provided with a top zone 12, a first structured packing layer 6, a plurality of reaction separation components and a bottom zone 14 from top to bottom, wherein the reaction separation component includes an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, the first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4; the total height of the acidic resin bed 7 is 10-30% of the height of the reaction distillation tower.

[0050] According to a third embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 includes a reaction distillation tower, which is sequentially provided with a top zone 12, a first structured packing layer 6, 2-4 reaction separation components and a bottom zone 14 from top to bottom, the reaction separation component includes an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, the first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4; the total height of the acidic resin bed 7 is 10-30% of the height of the reaction distillation tower; the number of the reaction separation components is 2-4.

[0051] According to a fourth embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 includes a reaction distillation tower, wherein the reaction distillation tower is sequentially provided with a top zone 12, a first structured packing layer 6, 2-4 reaction separation components and a bottom zone 14 from top to bottom, the reaction separation component includes an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, the first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4; the total height of the acidic resin bed 7 is 10-30% of the height of the reaction distillation tower; the number of the reaction separation components is 2-4; the acidic resin bed 7 also has a hydrogen peroxide inlet 3, and the NaA molecular sieve membrane component 2 has a first water outlet 8.

[0052] According to a fifth embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 includes a reaction distillation tower, which is sequentially provided with a tower top zone 12, a first structured packing layer 6, 2-4 reaction separation components and a tower bottom zone 14 from top to bottom, the reaction separation component includes an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, the first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4; the total height of the acidic resin bed 7 is 10-30% of the height of the reaction distillation tower; the number of the reaction separation components is 2-4; the acidic resin bed 7 also has a hydrogen peroxide inlet 3, and the NaA molecular sieve membrane component 2 has a first water outlet 8; the system also includes a condenser 5 and a phase separator 10, and the tower top zone 12 is sequentially connected to the condenser 5 and the phase separator 10 through a connecting pipe.

[0053] According to a sixth embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 comprises a reaction distillation tower, wherein the reaction distillation tower is sequentially provided with a tower top zone 12, a first structured packing layer 6, 2-4 reaction separation components and a tower bottom zone 14 from top to bottom, wherein the reaction separation component comprises an acid resin bed 7 and a NaA molecular sieve membrane component 2 located below the acid resin bed 7, wherein the first structured packing layer 6 has a mixed material inlet 1 of an organic acid above C3 and hydrogen peroxide, and the acid resin bed 7 has an organic solvent inlet 4; The total height of the acidic resin bed 7 is 10-30% of the height of the reaction distillation tower; the number of the reaction separation components is 2-4; the acidic resin bed 7 also has a hydrogen peroxide inlet 3, and the NaA molecular sieve membrane component 2 has a first water outlet 8; the system also includes a condenser 5 and a phase separator 10, and the tower top zone 12 is connected to the condenser 5 and the phase separator 10 in sequence through a connecting pipe; the organic solvent inlet 4 is connected to the phase separator 10, and is used to transport the organic solvent output by the phase separator 10 to the acidic resin bed 7.

[0054] According to a seventh embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids of C3 or above comprises a reaction distillation tower, wherein the reaction distillation tower is sequentially provided with a top zone 12, a first structured packing layer 6, 2-4 reaction separation components and a bottom zone 14 from top to bottom, wherein the reaction separation component comprises an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, wherein the first structured packing layer 6 has a mixed material inlet 1 of an organic acid of C3 or above and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4; the total height of the acidic resin bed 7 is 1 / 2 of the height of the reaction distillation tower. 10-30%; the number of the reaction separation components is 2-4; the acidic resin bed 7 also has a hydrogen peroxide inlet 3, and the NaA molecular sieve membrane component 2 has a first water outlet 8; the system also includes a condenser 5 and a phase separator 10, and the tower top zone 12 is connected to the condenser 5 and the phase separator 10 in sequence through a connecting pipe; the organic solvent inlet 4 is connected to the phase separator 10, and is used to transport the organic solvent output by the phase separator 10 to the acidic resin bed 7; the system also includes a second structured packing layer 13, and the bottom of the second structured packing layer 13 is connected to the tower bottom zone 14.

[0055] According to an eighth embodiment of the system of the present invention, the system for preparing anhydrous peroxyacids above C3 comprises a reaction distillation tower, wherein the reaction distillation tower is sequentially provided with a tower top zone 12, a first structured packing layer 6, 2-4 reaction separation components and a tower bottom zone 14 from top to bottom, the reaction separation component comprises an acidic resin bed 7 and a NaA molecular sieve membrane component 2 located below the acidic resin bed 7, the first structured packing layer 6 has a mixed material inlet 1 of organic acids above C3 and hydrogen peroxide, and the acidic resin bed 7 has an organic solvent inlet 4; the total height of the acidic resin bed 7 is 10-30% of the height of the reaction distillation tower; the number of the reaction separation components is 2-4; the acidic resin bed 7 also has a hydrogen peroxide inlet 3, and the NaA molecular sieve membrane component 2 has a first water outlet 8; the system also includes a condenser 5 and a phase separator 10, and the tower top zone 12 is sequentially connected to the condenser 5 and the phase separator 10 through a connecting pipe; the organic solvent inlet 4 is connected to the phase separator 10, and is used to transport the organic solvent output by the phase separator 10 to the acidic resin bed 7; the system also includes a second structured packing layer 13, and the bottom of the second structured packing layer 13 is connected to the tower bottom zone 14; the system also includes a reboiler 15 and an anhydrous peroxy acid receiving tank 16, and the tower bottom zone 14 is sequentially connected to the reboiler 15 and the anhydrous peroxy acid receiving tank 16 through a connecting pipe.

[0056] The second aspect of the present invention provides a method for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane assembly. The method is implemented in the above-mentioned system, and the method comprises: transporting an organic acid above C3 and hydrogen peroxide to the first structured packing layer 6 through the mixed material inlet 1 of the organic acid and hydrogen peroxide, and then reacting in the acidic resin bed 7, the reaction product is separated through the NaA molecular sieve membrane assembly 2, the separated anhydrous peroxyacid solution enters the bottom zone 14 of the tower, a part of the separated water forms an azeotropic mixture with the organic solvent transported to the acidic resin bed 7 through the organic solvent inlet 4, the azeotropic mixture enters the top zone 12 of the tower, and another part of the separated water is discharged through the first water outlet 8.

[0057] In the method of the present invention, in a specific embodiment, the weight ratio of the C3 or higher organic acid to the hydrogen peroxide is 1-4: 1. In a preferred embodiment, the weight ratio of the C3 or higher organic acid to the hydrogen peroxide is 2-3: 1.

[0058] In the method of the present invention, in a specific embodiment, the concentration of the hydrogen peroxide is 30-70% by weight. In a preferred embodiment, the concentration of the hydrogen peroxide is 45-55% by weight.

[0059] In the method of the present invention, in a specific embodiment, the feed conditions of the C3 or higher organic acid and hydrogen peroxide include: a feed temperature of 20-40°C and a feed flow rate of 2-5kg / h.

[0060] In the method of the present invention, in a specific embodiment, the temperature of the tower bottom zone 14 is 60-70°C.

[0061] In the method of the present invention, in a specific embodiment, the reaction conditions include: temperature of 40-80°C and pressure of 5-20KPa.

[0062] In the method of the present invention, in a specific embodiment, the organic acid is propionic acid and / or butyric acid.

[0063] In the method of the present invention, in a specific embodiment, the organic solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, methylene chloride and acetonitrile.

[0064] The following examples further illustrate the system for preparing C3 or higher anhydrous peroxyacids of the present invention. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples.

[0065] like Figure 1As shown, the embodiment and comparative example are implemented in the following system for preparing anhydrous peroxyacids above C3, wherein the system for preparing anhydrous peroxyacids above C3 comprises a reaction distillation tower, a condenser 5, a phase separator 10, a reboiler 15 and an anhydrous peroxyacid receiving tank 16, wherein the tower body of the reaction distillation tower is 3m in height, and the reaction distillation tower is provided with a tower top zone 12, a first structured packing layer 6, and three separation components from top to bottom, wherein the reaction separation component comprises an acid resin bed 7 and a NaA molecular sieve membrane component 2 located below the acid resin bed 7, a second structured packing layer 13 and a tower bottom zone 14, wherein the tower top zone 12 is sequentially connected to the condenser 5 and the phase separator 10 through a connecting pipe, and the tower bottom zone 14 is sequentially connected to the reboiler 15 and the anhydrous peroxyacid receiving tank 16 through a connecting pipe, and the filler in the first structured packing layer 6 is a wire mesh corrugated filler , the packing height is 0.5m, the packing in the second structured packing layer 13 is a wire mesh corrugated packing, the packing height is 0.5m, the first structured packing layer 6 has a mixed material inlet 1 of C3 or above organic acid and hydrogen peroxide, the acidic resin bed 7 contains 732 strong acid styrene cation exchange resin, the total height of the acidic resin bed 7 is 0.9m, the three acidic resin beds 7 all have an organic solvent inlet 4, from top to bottom, the second and third acidic resin beds 7 have a hydrogen peroxide inlet 3, the organic solvent inlet 4 is connected to the phase separator 10, and is used to transport the organic solvent output by the phase separator 10 to the acidic resin bed 7, the phase separator 10 has a second water outlet 11, the NaA molecular sieve membrane assembly 2 has a first water outlet 8, and the NaA molecular sieve membrane assembly 2 is composed of 100 NaA molecular sieve tubes.

[0066] Example 1

[0067] The method for preparing anhydrous peroxyacid comprises:

[0068] The bottom temperature of the reaction distillation tower is set to 60° C., the top temperature is set to 25° C., and the pressure is set to 10 KPa. The bottom area of ​​the tower is heated (the light component is evaporated and then condensed at the top of the tower). A raw material mixture containing 50% by mass of propionic acid and 50% by mass of hydrogen peroxide is transported to the first structured packing layer 6 through the mixed material inlet 1 of the organic acid and hydrogen peroxide. The feed flow rate of the raw material mixture is controlled to be 3 kg / h, and the feed temperature is set to 25° C. At the same time, ethyl propionate is added to the phase separator 10, and the liquid level of the ethyl propionate is kept level with the partition in the phase separator. The ethyl propionate is connected to the phase separator through a connecting pipe. The ester is sequentially transported from the organic solvent inlet 4 to three acidic resin beds 7, the propionic acid and hydrogen peroxide enter the first acidic resin bed 7 for reaction, the peroxy acid solution generated by the reaction enters the first NaA molecular sieve membrane assembly 2 for separation, the primary peroxy acid product obtained by separation enters the second acidic resin bed 7, a portion of the separated water forms an azeotropic mixture with ethyl propionate and enters the tower top zone 12, and the other portion of the separated water is discharged through the first water outlet 8; at the same time, hydrogen peroxide with a temperature of 35°C and a flow rate of 2kg / h is input into the second acidic resin bed 7 through the hydrogen peroxide inlet 3. The primary peroxy acid product reacts with hydrogen peroxide in the second acidic resin bed 7, and the peroxy acid solution generated by the reaction enters the second NaA molecular sieve membrane assembly 2 for separation. The separated secondary peroxy acid product enters the third acidic resin bed 7, and a portion of the separated water forms an azeotropic mixture with ethyl propionate and enters the top zone 12, and the other portion of the separated water is discharged through the first water outlet 8; at the same time, hydrogen peroxide with a temperature of 40° C. and a flow rate of 1 kg / h is input into the third acidic resin bed 7 through the hydrogen peroxide inlet 3, and the secondary peroxy acid product reacts with the hydrogen peroxide. The peroxyacid solution generated by the reaction enters the third NaA molecular sieve membrane assembly 2 for separation, and the separated tertiary peroxyacid product enters the second structured packing layer 13, and then enters the tower bottom zone 14 with a temperature of 65°C, and the reboiler 15 is controlled to have a reboiling ratio of 3:1. The finally obtained peroxyacid product is collected in the anhydrous peroxyacid receiving tank 16, and the azeotropic mixture is sequentially condensed in the condenser 5, and phase-separated in the phase separator 10. The separated water phase is discharged from the second water outlet 11, and the separated ethyl propionate is transported to the acid resin bed 7 through the organic solvent inlet 4 for recycling. The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 41.89wt% of propionic acid, 28.92wt% of peroxypropionic acid, and 29.19wt% of ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 98.2%, and the selectivity of peroxypropionic acid is 99.0%.

[0069] Application Example 1

[0070] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 200 rpm. 68.3 g of the peroxyacid product obtained in Example 1 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.5%, the selectivity of the caprolactone was 98.5%, and the yield of the caprolactone was 98.0%.

[0071] Example 2

[0072] The method of Example 1 is followed, except that the acidic resin bed 7 contains Amberlyst-15 type ion exchange resin. The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 41wt% propionic acid, 28wt% peroxypropionic acid, and 31wt% ethyl propionate. The conversion rate of hydrogen peroxide is 99.8% and the selectivity of peroxypropionic acid is 98.2%.

[0073] Application Example 2

[0074] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 200 rpm. 64 g of the peroxyacid product obtained in Example 2 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.5%, the selectivity of the caprolactone was 99%, and the yield of the caprolactone was 98.5%.

[0075] Example 3

[0076] The method of Example 1 is followed, except that the acidic resin bed 7 contains Amberlyst IR-120 ion exchange resin. The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 42 wt % propionic acid, 25 wt % peroxypropionic acid, and 33 wt % ethyl propionate. The conversion rate of hydrogen peroxide is 99.0%, and the selectivity of peroxypropionic acid is 98.0%.

[0077] Application Example 3

[0078] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 77 g of the peroxyacid product obtained in Example 3 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.2%, the selectivity of the caprolactone was 99%, and the yield of the caprolactone was 98.2%.

[0079] Example 4

[0080] The method is implemented in the same manner as in Example 1, except that the reactive distillation column includes two reactive separation components (an acidic resin bed and a NaA molecular sieve membrane component located below the acidic resin bed). The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 41.5wt% of propionic acid, 26wt% of peroxypropionic acid, and 32.5wt% of ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 99.9%, and the selectivity of peroxypropionic acid is 98%.

[0081] Application Example 4

[0082] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 74 g of the peroxyacid product obtained in Example 4 was slowly added dropwise to the cyclohexanone, and the addition was completed for 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.3%, the selectivity of the caprolactone was 99.0%, and the yield of the caprolactone was 98.30%.

[0083] Example 5

[0084] The method is implemented in the same manner as in Example 1, except that the reactive distillation column includes 4 reactive separation components (an acidic resin bed and a NaA molecular sieve membrane component located below the acidic resin bed). The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 42wt% of propionic acid, 28wt% of peroxypropionic acid, and 30wt% of ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 99.9%, and the selectivity of peroxypropionic acid is 98.0%.

[0085] Application Example 5

[0086] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 69 g of the peroxyacid product obtained in Example 5 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 98.9%, the selectivity of the caprolactone was 99%, and the yield of the caprolactone was 98%.

[0087] Example 6

[0088] The method of Example 1 is implemented, except that a raw material mixture containing 75% by mass of butyric acid and 25% by mass of hydrogen peroxide is transported to the first structured packing layer 6 through the organic acid and hydrogen peroxide mixture inlet 1. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contains 40wt% of butyric acid, 25wt% of peroxybutyric acid, and 35wt% of ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 99.2%, and the selectivity of peroxybutyric acid is 98%.

[0089] Application Example 6

[0090] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 88 g of the peroxyacid product obtained in Example 6 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 60° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.0%, the selectivity of the caprolactone was 98.0%, and the yield of the caprolactone was 97.0%.

[0091] Example 7

[0092] The method of Example 1 is followed, except that the temperature in the reaction distillation tower is set to 70° C. and the pressure is set to 20 KPa. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contains 41 wt % of propionic acid, 26 wt % of peroxy propionic acid, and 33 wt % of ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 99.8%, and the selectivity of peroxy propionic acid is 97.8%.

[0093] Application Example 7

[0094] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 40 rpm. 74.2 g of the peroxyacid product obtained in Example 7 was slowly added dropwise to the cyclohexanone, and the addition was completed for 0.5 h. The reaction was then allowed to stand at 60° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.2%, the selectivity of the caprolactone was 98.5%, and the yield of the caprolactone was 99.7%.

[0095] Example 8

[0096] The method of Example 1 was followed, except that the feed rate of the raw material mixture was controlled to be 3 kg / h and the feed temperature was 40° C. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contained 41 wt % of propionic acid, 26 wt % of peroxy propionic acid, and 33 wt % of ethyl propionate. The conversion rate of hydrogen peroxide was 99.7% and the selectivity of peroxy propionic acid was 97.9% after measurement and calculation.

[0097] Application Example 8

[0098] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 74.5 g of the peroxyacid product obtained in Example 8 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 60° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.3%, the selectivity of the caprolactone was 98.4%, and the yield of the caprolactone was 97.7%.

[0099] Example 9

[0100] The method of Example 1 is implemented, except that a raw material mixture containing 87.5% by mass of butyric acid and 12.5% ​​by mass of hydrogen peroxide is transported to the first structured packing layer 6 through the organic acid and hydrogen peroxide mixture inlet 1. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contains 41.1 wt % of propionic acid, 26 wt % of peroxy propionic acid, and 32.9 wt % of ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 97.7%, and the selectivity of peroxy propionic acid is 98.2%.

[0101] Application Example 9

[0102] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 74.12 g of the peroxyacid product obtained in Example 9 was slowly added dropwise to the cyclohexanone, and the addition was completed for 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.2%, the selectivity of the caprolactone was 98.3%, and the yield of the caprolactone was 97.5%.

[0103] Example 10

[0104] The method of Example 1 is implemented, except that the height of the reactive distillation tower is 5m, and the total height of the acidic resin bed 7 is 2.5m. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contains 41wt% propionic acid, 26wt% peroxy propionic acid, and 33wt% ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 97.7%, and the selectivity of peroxy propionic acid is 98.0%.

[0105] Application Example 10

[0106] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 400 rpm. 74.2 g of the peroxyacid product obtained in Example 10 was slowly added dropwise to the cyclohexanone, and the addition was completed for 0.5 h. The reaction was then allowed to stand at 550° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.2%, the selectivity of the caprolactone was 98.5%, and the yield of the caprolactone was 97.7%.

[0107] Comparative Example 1

[0108] The reaction was carried out in the manner of Example 1, except that the acid resin bed 7 was not provided in the reaction distillation tower, and the first structured packing layer 6 had a mixed material inlet 1 of organic acid, hydrogen peroxide, acid catalyst and organic solvent. In the actual operation process, the temperature in the reaction distillation tower was set to 60°C and the pressure was set to 10KPa, the bottom area of ​​the tower was heated, and a raw material mixture containing 41% propionic acid, 17.8% hydrogen peroxide (hydrogen peroxide concentration was 50%), 0.2% sulfuric acid (concentration was 98%), and 41% ethyl propionate was transported to the first structured packing layer 6 through the mixed material inlet 1 and reacted, and the reaction product was separated through the NaA molecular sieve membrane assembly 2, a part of the separated water formed an azeotropic mixture with ethyl propionate and entered the tower top area 12, and the other part was discharged through the first water outlet 8, and the separated peroxypropionic acid product entered the tower bottom area 14 and was collected in the anhydrous peroxyacid receiving tank 16. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contains 42% propionic acid, 14.6wt% peroxypropionic acid, and 44wt% ethyl propionate. According to measurement and calculation, the conversion rate of hydrogen peroxide is 49% and the selectivity of peroxypropionic acid is 50%.

[0109] Comparative application example 1

[0110] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 400 rpm. 132 g of the peroxyacid product obtained in Comparative Example 1 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 90%, the selectivity of the caprolactone was 80%, and the yield of the caprolactone was 72%.

[0111] Comparative Example 2

[0112] The method of Example 1 is implemented, except that the NaA molecular sieve membrane assembly 2 in the reaction distillation tower is replaced with a β-type molecular sieve membrane. The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 41wt% propionic acid, 14wt% peroxypropionic acid, 43wt% ethyl propionate, and 2wt% water. According to measurement and calculation, the conversion rate of hydrogen peroxide is 80%, and the selectivity of peroxypropionic acid is 90%.

[0113] Comparative Application Example 2

[0114] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 133 g of the peroxyacid product obtained in Comparative Example 2 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 90%, the selectivity of the caprolactone was 85%, and the yield of the caprolactone was 76.5%.

[0115] Comparative Example 3

[0116] The method of Example 1 is implemented, except that the NaA molecular sieve membrane assembly 2 in the reaction distillation tower is replaced with a ZSM-5 molecular sieve membrane. The peroxyacid product collected in the anhydrous peroxyacid receiving tank 16 contains 39wt% propionic acid, 18.1wt% peroxypropionic acid, 40.9wt% ethyl propionate, and 2wt% water. According to measurement and calculation, the conversion rate of hydrogen peroxide is 85%, and the selectivity of peroxypropionic acid is 91%.

[0117] Comparative Application Example 3

[0118] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 106.5 g of the peroxyacid product obtained in Comparative Example 3 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 89%, the selectivity of the caprolactone was 90%, and the yield of the caprolactone was 80.1%.

[0119] Comparative Example 4

[0120] The method is implemented in the manner of Example 1, except that the acidic resin bed 7 and the NaA molecular sieve membrane assembly 2 are not arranged at intervals. Specifically, three acidic resin beds 7 are connected in sequence, and three NaA molecular sieve membrane assemblies 2 are connected in sequence. From top to bottom, the top of the first acidic resin bed 7 is connected to the first structured packing layer 6, and the bottom of the third acidic resin bed 7 is connected to the first NaA molecular sieve membrane assembly 2. The peroxy acid product collected in the anhydrous peroxy acid receiving tank 16 contains 41.2wt% of propionic acid, 15wt% of peroxy propionic acid, 41.8wt% of ethyl propionate, and 2wt% of water. After measurement and calculation, the conversion rate of hydrogen peroxide is 49.4%, and the selectivity of peroxy propionic acid is 50%.

[0121] Comparative Application Example 4

[0122] 20 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C., magnetic stirring was turned on, and the stirring speed was 300 rpm. 128.5 g of the peroxyacid product obtained in Comparative Example 4 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 h. The reaction was then allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 95%, the selectivity of the caprolactone was 80%, and the yield of the caprolactone was 76%.

[0123] The system of the present invention is used to prepare anhydrous peroxyacid, which can effectively reduce the energy consumption of a reaction distillation tower, accelerate the reaction speed, prevent the decomposition and explosion of peroxide, and effectively avoid the loss of a catalyst in the later stage. When the obtained anhydrous peroxyacid is used to oxidize cyclohexanone to prepare caprolactone, the polycondensation reaction of caprolactone will not occur, thereby improving the selectivity and yield of caprolactone. The selectivity of caprolactone is greater than 98%, and the yield is greater than 97%.

[0124] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A system for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane module, characterized in that: The system comprises a reaction distillation tower, wherein the reaction distillation tower is provided with a tower top region (12), a first structured packing layer (6), a plurality of reaction separation components and a tower bottom region (14) in order from top to bottom, the reaction separation component comprises an acid resin bed (7) and a NaA molecular sieve membrane component (2) located below the acid resin bed (7), the first structured packing layer (6) has a mixed material inlet (1) of an organic acid with a C3 or higher content and hydrogen peroxide, and the acid resin bed (7) has an organic solvent inlet (4).

2. The system according to claim 1, characterized in that The total height of the acidic resin bed (7) is 10-30% of the height of the reactive distillation tower.

3. The system according to claim 1 or 2, characterized in that: The number of the reaction separation components is 2-4.

4. The system according to any one of claims 1 to 3, characterized in that: The acidic resin bed (7) also has a hydrogen peroxide inlet (3); Preferably, the NaA molecular sieve membrane assembly (2) has a first water outlet (8).

5. The system according to any one of claims 1 to 4, characterized in that: The system further comprises a condenser (5) and a phase separator (10), wherein the tower top region (12) is sequentially connected to the condenser (5) and the phase separator (10) via a connecting pipe; Preferably, the phase separator (10) has a second water outlet (11).

6. The system according to claim 5, characterized in that The organic solvent inlet (4) is in communication with the phase separator (10) and is used to transport the organic solvent output from the phase separator (10) to the acidic resin bed (7).

7. The system according to any one of claims 1 to 6, characterized in that: The system further comprises a second structured packing layer (13), the bottom of which is connected to the tower bottom zone (14).

8. The system according to any one of claims 1 to 7, characterized in that: The system further comprises a reboiler (15) and an anhydrous peroxyacid receiving tank (16), and the tower bottom zone (14) is connected to the reboiler (15) and the anhydrous peroxyacid receiving tank (16) in sequence through a connecting pipe.

9. A method for preparing anhydrous peroxyacids above C3 by coupling a resin bed with a NaA membrane assembly, characterized in that: The method is implemented in the system described in any one of claims 1 to 8, characterized in that the method comprises: transporting an organic acid of C3 or above and hydrogen peroxide to the first structured packing layer (6), and then entering the acidic resin bed (7) for reaction, the product obtained by the reaction is separated by the NaA molecular sieve membrane component (2), the anhydrous peroxyacid solution obtained by separation enters the bottom zone (14) of the tower, the separated water forms an azeotropic mixture with the organic solvent transported to the acidic resin bed (7) through the organic solvent inlet (4), and the azeotropic mixture enters the top zone (12) of the tower.

10. The method according to claim 9, characterized in that The weight ratio of the C3 or higher organic acid to hydrogen peroxide is 1-4:1, preferably 2-3:1; Preferably, the concentration of the hydrogen peroxide is 30-70% by weight.

11. The method according to claim 9 or 10, characterized in that: The feed conditions of the C3 or higher organic acid and hydrogen peroxide include: feed temperature of 20-40°C, feed flow rate of 2-5kg / h; Preferably, the temperature of the bottom zone (14) is 60-70°C.

12. The method according to any one of claims 9 to 11, characterized in that: The reaction conditions include: temperature of 40-80° C. and pressure of 5-20 KPa.

13. The method according to any one of claims 9 to 12, characterized in that: The C3 or higher organic acid is propionic acid and / or butyric acid; Preferably, the organic solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, methylene chloride and acetonitrile.

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