Method for preparing peroxy acid

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a method for preparing peroxy acid. The method comprises the following steps: S1, carrying out reaction on organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor, and introducing a product obtained by the reaction into a first reactive distillation tower for reaction; s2, reacting the product obtained in the step S1 in a second pre-reactor, and introducing the product into a second reactive distillation tower for reaction after the reaction is finished; s3, the product obtained in the step S2 and a stabilizer are subjected to a reaction in a mixer, the stabilizer is a nitrogen-containing alkaline compound, lone pair electrons exist on N atoms, and the catalyst is selected from one or two or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid. By adopting the method to prepare the peroxy acid solution, the selectivity and yield of peroxy acid can be improved, and the total conversion rate of hydrogen peroxide is gt; the selectivity of peroxy acid is gt; meanwhile, caprolactone is prepared by using the peroxy acid to dissolve cyclohexanone oxide liquid, and the conversion rate of cyclohexanone is gt; the selectivity of the obtained caprolactone is gt; 85%.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing peroxy acid, and in particular to a method for continuously preparing peroxy acid. Background Art

[0002] Organic peroxyacid is an oxidant with excellent performance. It is used as a highly effective disinfectant and sterilizer in daily life. It can also be used as a bleaching agent for the bleaching of textiles, paper, paraffin, and oils. In industry, it is mainly used to oxidize cyclohexanone to produce caprolactone. The peroxyacid synthesis reaction formula is RCOOH+H2O2→RCOOOH+H2O. This reaction is a nucleophilic reaction and also a balanced reaction. Due to the weak affinity of hydrogen peroxide, it is difficult to react nucleophilically with the carbonyl position of organic acid, resulting in limited reaction kinetics and low reaction rate. At the same time, in the peroxyacid production process, heteropolyacids, nitric acid, sulfuric acid, etc. are usually used as catalysts to improve the reaction efficiency. However, this reaction is a homogeneous reaction, and the acid catalyst remains in the product solution and cannot be separated. The residual catalyst will affect the quality of the product peroxyacid.

[0003] CN1034500C discloses a method for synthesizing peroxypropionic acid using boric acid as a catalyst, the acidity of boric acid is weak, and the synthetic effect of bringing it into the downstream on caprolactone is also weak, and no excessive side reactions will be produced, but the weak acidity of boric acid will limit the synthesis efficiency of peroxyacid, and the residence time of materials in the reaction distillation tower during the synthesis is extremely long, and the risk of decomposition out of control is high due to the long reaction time. CN103570667A discloses a method for continuously preparing caprolactone, using boric acid as a catalyst, hydrogen peroxide as an oxidant, and continuously oxidizing organic carboxylic acids in multiple reaction distillation towers to obtain peroxyacid, and then continuously introducing peroxyacid and cyclohexanone into multiple series stirring tanks to react to obtain caprolactone solution. Boric acid is a weak acid that has little effect on the polymerization of caprolactone, but its catalytic peroxyacid synthesis efficiency is low, and multiple reaction distillation towers are connected in series to increase energy consumption, which is also not conducive to industrial production. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the use of weak acid catalysts in the prior art when preparing peroxyacids will lead to a long reaction residence time or increase energy consumption by connecting multiple reaction distillation towers in series, and the problem that the residual acid catalyst in the peroxyacid product affects the quality of caprolactone when preparing caprolactone, thereby proposing a method for preparing peroxyacids. The method firstly passes a peroxyacid raw material containing a specific acid catalyst into two pre-reactors-reaction distillation towers connected in series for reaction, and then reacts the finally obtained peroxyacid synthetic solution with a specific stabilizer to obtain a stable peroxyacid solution. The peroxyacid solution is prepared by the method of the present invention, which can improve the selectivity and yield of the peroxyacid, so that the total conversion rate of hydrogen peroxide is greater than 95%, and the selectivity of the peroxyacid is greater than 65%. At the same time, when the peroxyacid solution is used to oxidize cyclohexanone to prepare caprolactone, the conversion rate of cyclohexanone is greater than 85%, and the selectivity of the obtained caprolactone is greater than 85%.

[0005] The present invention provides a method for preparing peroxyacid, which comprises the following steps:

[0006] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor, and then passing the obtained reaction product into a first reactive distillation tower for reaction;

[0007] S2, passing the bottom product of the first reaction distillation tower into a second pre-reactor for reaction, and then passing the obtained reaction product into a second reaction distillation tower for reaction;

[0008] S3, reacting the bottom product of the second reaction distillation tower with a stabilizer,

[0009] Wherein, the stabilizer is a nitrogen-containing basic compound, and the N atom has a lone pair of electrons.

[0010] The catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid.

[0011] Preferably, the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline.

[0012] Preferably, the molar ratio of the stabilizer to the catalyst is 0.5-30:1.

[0013] Preferably, the first pre-reactor and the second pre-reactor are each independently selected from a microchannel reactor, a fixed bed reactor, a tank reactor, a static mixing reactor or a membrane reactor.

[0014] Preferably, the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid.

[0015] Preferably, the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile.

[0016] Preferably, in step S1, based on the total weight of the solvent, organic acid, hydrogen peroxide and catalyst as 100 weight %, the content of the solvent is 5-70 weight %, the content of the organic acid is 5-70 weight %, the content of the hydrogen peroxide is 5-70 weight %, and the content of the catalyst is 0.01-15 weight %.

[0017] Preferably, the isopoly acid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid and dodecamolybdic acid.

[0018] Preferably, the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid.

[0019] Preferably, the concentration of peroxyacid in the solution obtained by the reaction in step S3 is 5-35% by weight.

[0020] Preferably, the reaction conditions of the first pre-reactor include: temperature of 0-100° C., pressure of 0.1-0.5 MPa, and residence time of 0.05-5 h.

[0021] Preferably, the reaction conditions of the second pre-reactor include: temperature of 0-100°C, pressure of 0.1-0.5 MPa, and residence time of 0.05-5h.

[0022] Preferably, the reaction conditions of the first reactive distillation tower include: temperature of 25-75°C, pressure of 0.002-0.2 MPa, and residence time of 0.05-2.5 h.

[0023] Preferably, the reaction conditions of the second reactive distillation tower include: temperature of 35-85°C, pressure of 0.002-0.2MPa, and residence time of 0.05-3h.

[0024] Preferably, in step S3, the reaction conditions include: temperature of -20-65°C and time of 0.1-3h.

[0025] In the method of the present invention, by reacting a peracid raw material containing a specific acid catalyst in two pre-reactor-reaction distillation tower devices connected in series in sequence, efficient synthesis of peracid can be achieved. At the same time, since the synthesis process in the pre-reactor does not consume additional energy, and the two pre-reactor-reaction distillation tower devices connected in series are combined, energy consumption can be reduced, which is conducive to industrial production. The finally obtained peracid synthesis solution is reacted with a specific stabilizer to optimize the quality of the peracid synthesis solution. Caprolactone is prepared using the optimized peracid synthesis solution to obtain caprolactone with high selectivity and high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of a system for preparing peroxyacid according to one embodiment of the present invention.

[0027] Description of Reference Numerals

[0028] 1. First pre-reactor; 2. First reaction distillation tower; 3. Second pre-reactor; 4. Second reaction distillation tower; 5. Mixer. DETAILED DESCRIPTION

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The present invention provides a method for preparing peroxyacid, which comprises the following steps:

[0033] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0034] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0035] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer,

[0036] Wherein, the stabilizer is a nitrogen-containing basic compound, and the N atom has a lone pair of electrons.

[0037] The catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid.

[0038] In the method of the present invention, in a specific embodiment, the organic acid can be a conventional choice in the art, as long as it is liquid or soluble in a solvent. In a preferred embodiment, the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid.

[0039] In the method of the present invention, in a specific embodiment, hydrogen peroxide is used as a source of hydrogen peroxide. Specifically, the concentration of the hydrogen peroxide is 10-90% by weight, preferably 25-50%.

[0040] In the method of the present invention, in a specific embodiment, the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile.

[0041] In the method of the present invention, if anhydrous peroxyacid is to be produced, it is preferred to use a solvent that can form an azeotrope with water and can form an oil-water two-phase substance with water after cooling, so as to facilitate the separation and recovery of the solvent. In a preferred embodiment, the solvent is selected from one or more of ethyl propionate, dichloromethane and cyclohexane.

[0042] In the method of the present invention, in a specific embodiment, the isopolyacid and heteropolyacid have no special requirements and may contain element doping modification.

[0043] In the method of the present invention, in a preferred embodiment, the isopoly acid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid and dodecamolybdic acid.

[0044] In the method of the present invention, in a preferred embodiment, the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid.

[0045] In the method of the present invention, in a specific embodiment, in step S1, based on the total weight of the solvent, organic acid, hydrogen peroxide and catalyst as 100 weight%, the content of the solvent is 5-70 weight%, the content of the organic acid is 5-70 weight%, the content of the hydrogen peroxide is 5-70 weight%, and the content of the catalyst is 0.01-15 weight%.

[0046] In order to improve the synthesis efficiency of peroxyacid and reduce energy consumption, in a preferred embodiment, in step S1, based on the total weight of the solvent, organic acid, hydrogen peroxide and catalyst as 100 weight%, the content of the solvent is 10-50 weight%, for example, 10 weight%, 20 weight%, 27 weight%, 40 weight% or 50 weight%; the content of the organic acid is 10-50 weight%, for example, 10 weight%, 20 weight%, 30 weight%, 46 weight%, 50 weight%; the content of the hydrogen peroxide is 10-60 weight%, for example, 10 weight%, 20 weight%, 27 weight%, 40 weight% or 50 weight%; the content of the catalyst is 0.05-10 weight%, for example, 0.05 weight%, 0.1 weight%, 1 weight%, 2 weight%, 5 weight% or 10 weight%.

[0047] In the method of the present invention, in a specific embodiment, the first pre-reactor 1 is selected from a microchannel reactor, a fixed bed reactor, a tank reactor, a static mixing reactor or a membrane reactor. Specifically, the first pre-reactor 1 can be a combination of one reactor or multiple reactors. In the specific operation process, the organic acid, hydrogen peroxide, catalyst and solvent are fed into the first pre-reactor 1 separately or in mixture, and the feed temperature is controlled to be 20-30°C, and the feed flow rate is 0.1-10kg / h.

[0048] In the method of the present invention, in a specific embodiment, the reaction conditions of the first pre-reactor 1 include: temperature of 0-100°C, pressure of 0.1-0.5 MPa, residence time of 0.05-5h. In a preferred case, the temperature is 35-80°C.

[0049] In the method of the present invention, in a specific embodiment, in step S1, the concentration of peroxy acid in the product obtained by the reaction in the first pre-reactor 1 is 5-10% by weight.

[0050] In the first pre-reactor 1, the reaction of preparing peracid by organic acid, hydrogen peroxide, catalyst and solvent reaches or approaches chemical equilibrium. In order to make the reaction continue to move forward and improve the synthesis efficiency of peracid, in the method of the present invention, in a specific embodiment, the product obtained by the reaction in the first pre-reactor 1 is passed into the first reactive distillation tower 2 for reaction.

[0051] In the method of the present invention, in a specific embodiment, the first reaction distillation tower 2 can be a conventional choice in the art. The first reaction distillation tower 2 is provided with 15-50 theoretical plates. In the specific operation process, the product obtained from the first pre-reactor 1 is input into the first reaction distillation tower 2, and the feeding position is the middle and lower part of the first reaction distillation tower 2. At the same time, materials can be supplemented according to demand during the reaction process. The materials include organic acids, hydrogen peroxide, catalysts and solvents. Specifically, the feeding position of the supplementary materials is the upper part of the first reaction distillation tower 2, and the feeding temperature of the supplementary materials is 10-50°C, and the feed flow rate is 0.1-10kg / h.

[0052] In the method of the present invention, in a specific embodiment, the reaction conditions of the first reactive distillation tower 2 include: a temperature of 25-75°C, a pressure of 0.002-0.2MPa, and a residence time of 0.05-2.5h. In a preferred embodiment, the residence time is 0.3-1h. The reaction temperature here refers to the temperature of the tower section containing hydrogen peroxide and peroxyacid.

[0053] In the method of the present invention, in the specific operation process, in the first reaction distillation tower 2, the water generated by the reaction is mixed with the solvent having water properties to form an azeotrope and enters the top of the tower. The temperature of the top of the tower is 25-30°C. The azeotrope is condensed at the top of the tower and phase-separated in a phase separator. The oil phase (solvent) obtained by phase separation is completely refluxed, that is, refluxed to the first reaction distillation tower 2 for reuse, the water obtained by phase separation is extracted, and the product generated by the reaction is extracted from the bottom of the tower. The extraction temperature of the bottom of the tower is 50-75°C. The product is a peroxyacid product that has not reached chemical equilibrium.

[0054] In the method of the present invention, in a specific embodiment, in step S1, the concentration of peroxy acid in the product obtained by the reaction in the first reaction distillation tower 2 is 5-10% by weight.

[0055] In order to improve the synthesis efficiency of peroxyacid, in the method of the present invention, in a specific embodiment, the bottom product of the first reaction distillation tower 2 is introduced into the second pre-reactor 3 for reaction.

[0056] In the method of the present invention, in a specific embodiment, the second pre-reactor 3 is selected from a microchannel reactor, a fixed bed reactor, a tank reactor, a static mixing reactor or a membrane reactor. Specifically, the second pre-reactor 3 can be a combination of one reactor or multiple reactors. In the specific operation process, the bottom product of the first reaction distillation tower 2 is passed into the second pre-reactor 3, and the feed temperature is controlled to be 20-30°C and the feed flow rate is 0.2-20kg / h.

[0057] In the method of the present invention, in a specific embodiment, the reaction conditions of the second pre-reactor 3 include: temperature of 0-100°C, pressure of 0.1-0.5MPa, residence time of 0.05-5h. In a preferred case, the temperature is 35-80°C.

[0058] In the method of the present invention, in a specific embodiment, in step S2, the concentration of peroxy acid in the product obtained by the reaction in the second pre-reactor 3 is 15-20% by weight.

[0059] In the method of the present invention, in a specific embodiment, the second reaction distillation tower 4 can be a conventional choice in the art. The second reaction distillation tower 4 is provided with 15-45 theoretical plates. In the specific operation process, the product obtained from the second pre-reactor 3 is input into the second reaction distillation tower 4, and the feeding position is the middle and lower part of the second reaction distillation tower 4. During the reaction process, materials can be supplemented according to demand, and the materials include organic acids, hydrogen peroxide, catalysts and solvents. Specifically, the feeding position of the supplementary materials is the upper part of the second reaction distillation tower 4, and the feeding temperature of the supplementary materials is 10-50°C, and the feed flow rate is 0.1-10kg / h.

[0060] In the method of the present invention, in a specific embodiment, the reaction conditions of the second reaction distillation tower 4 include: temperature of 35-85°C, pressure of 0.002-0.2MPa, and residence time of 0.05-30h. In a preferred embodiment, the residence time is 0.1-10h. The reaction temperature here refers to the temperature of the tower section containing hydrogen peroxide and peroxyacid.

[0061] In the method of the present invention, in the specific operation process, in the second reaction distillation tower 4, the water generated by the reaction is mixed with the solvent having water properties to form an azeotrope and enters the top of the tower. The temperature of the top of the tower is 25-30°C. The azeotrope is condensed at the top of the tower and phase-separated in a phase separator. The oil phase (solvent) obtained by phase separation is completely refluxed, that is, refluxed to the second reaction distillation tower 4 for reuse. The water obtained by phase separation is extracted, and the product generated by the reaction is extracted from the bottom of the tower. The extraction temperature of the bottom of the tower is 55-85°C. The product is a peroxyacid product that has reached chemical equilibrium.

[0062] In the method of the present invention, in a specific embodiment, in step S1, the concentration of peroxy acid in the product obtained by the reaction in the second reaction distillation tower 4 is 20-35% by weight.

[0063] In order to optimize the quality of the finally obtained peracid product and improve its stability, the optimized peracid product can be used to prepare caprolactone with higher selectivity and yield. In the method of the present invention, in a specific embodiment, the bottom product of the second reaction distillation tower 4 is reacted with a stabilizer. In a specific embodiment, the molar ratio of the stabilizer to the catalyst is 0.5-30:1. In a preferred embodiment, the molar ratio of the stabilizer to the catalyst is 1-10:1, for example, 1:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1.

[0064] In the method of the present invention, in a specific embodiment, the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline. In a preferred embodiment, the stabilizer is selected from one or more of pyridine, ethylamine, cyclohexylamine and urea.

[0065] In the method of the present invention, in a specific embodiment, the reaction in step S3 can be carried out in a mixer 5, and the mixer 5 can be a conventional choice in the art. In a preferred embodiment, the mixer 5 is a static mixer or a reactor with a stirring function.

[0066] In the method of the present invention, in a specific embodiment, in step S3, the reaction conditions include: temperature of -20-60°C, time of 0.1-3h.

[0067] In the method of the present invention, in a specific embodiment, the pH value of the solution obtained by the reaction in step S3 is -1 to 3.

[0068] According to a first embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0069] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0070] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0071] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is a nitrogen-containing alkaline compound, and the N atom has a lone pair of electrons, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopoly acid and heteropoly acid.

[0072] According to a second embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0073] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0074] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0075] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacids and heteropolyacids.

[0076] According to a third embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0077] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0078] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0079] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacids and heteropolyacids; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a fixed bed reactor, a kettle reactor, a static mixing reactor or a membrane reactor.

[0080] According to a fourth embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0081] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0082] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0083] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacids and heteropolyacids; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a fixed bed reactor, a kettle reactor, a static mixing reactor or a membrane reactor; the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid, and the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile.

[0084] According to a fifth embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0085] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0086] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0087] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a fixed bed reactor, a kettle reactor, a static mixing reactor or a membrane reactor ; The organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid, and the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile; based on the total weight of the organic solvent, organic acid, hydrogen peroxide and catalyst as 100 weight%, the content of the organic solvent is 5-70 weight%, the content of the organic acid is 5-70 weight%, the content of the hydrogen peroxide is 5-70 weight%, and the content of the catalyst is 0.01-15 weight%.

[0088] According to a sixth embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0089] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0090] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0091] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacids and heteropolyacids; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a fixed bed reactor, a tank reactor, a static mixing reactor or a membrane reactor; the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid, and the The solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile; based on the total weight of the organic solvent, organic acid, hydrogen peroxide and catalyst as 100 weight%, the content of the organic solvent is 5-70 weight%, the content of the organic acid is 5-70 weight%, the content of the hydrogen peroxide is 5-70 weight%, and the content of the catalyst is 0.01-15 weight%; the isopoly acid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid and dodecamolybdic acid, and the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid.

[0092] According to a seventh embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0093] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0094] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0095] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacids and heteropolyacids; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a fixed bed reactor, a kettle reactor, a static mixing reactor or a membrane reactor; the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid, and the solvent is selected from ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane one or more of alkane and acetonitrile; based on the total weight of the organic solvent, organic acid, hydrogen peroxide and catalyst as 100 weight %, the content of the organic solvent is 5-70 weight %, the content of the organic acid is 5-70 weight %, the content of the hydrogen peroxide is 5-70 weight %, and the content of the catalyst is 0.01-15 weight %; the isopoly acid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid and dodecamolybdic acid, and the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid; the reaction conditions of the first pre-reactor 1 include: temperature of 0-100 ° C, pressure of 0.1-0.5 MPa, residence time of 0.05-5h, and the reaction conditions of the second pre-reactor 3 include: temperature of 0-100 ° C, pressure of 0.1-0.5 MPa, residence time of 0.05-5h.

[0096] According to an eighth embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0097] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0098] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0099] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from micro-channel The organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid; the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile; based on the total weight of the organic solvent, organic acid, hydrogen peroxide and catalyst as 100% by weight, the content of the organic solvent is 5- 70% by weight, the content of the organic acid is 5-70% by weight, the content of the hydrogen peroxide is 5-70% by weight, and the content of the catalyst is 0.01-15% by weight; the isopoly acid is selected from one or more of decatungstic acid, heptungstic acid, octamolybdic acid and dodecamolybdic acid, and the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid; the reaction conditions of the first pre-reactor 1 include: temperature of 0-100°C, pressure of 0.1-0.5MPa, residence time of 0.05- 5h, the reaction conditions of the second pre-reactor 3 include: temperature of 0-100°C, pressure of 0.1-0.5MPa, and residence time of 0.05-5h; the reaction conditions of the first reaction distillation tower 2 include: temperature of 25-75°C, pressure of 0.002-0.2MPa, and residence time of 0.05-2.5h, and the reaction conditions of the second reaction distillation tower 4 include: temperature of 35-85°C, pressure of 0.002-0.2MPa, and residence time of 0.05-3h.

[0100] According to a ninth embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0101] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0102] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0103] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a solid A fixed bed reactor, a kettle reactor, a static mixing reactor or a membrane reactor; the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid, and the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile; based on the total weight of the organic solvent, organic acid, hydrogen peroxide and catalyst as 100 weight %, the content of the organic solvent is 5-70 weight %, the content of the organic acid is 10 weight %. The content is 5-70% by weight, the content of the hydrogen peroxide is 5-70% by weight, and the content of the catalyst is 0.01-15% by weight; the isopoly acid is selected from one or more of decatungstic acid, heptungstic acid, octamolybdic acid and dodecamolybdic acid, and the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid; the reaction conditions of the first pre-reactor 1 include: temperature of 0-100°C, pressure of 0.1-0.5MPa, residence time of 0.05-5h, and the reaction conditions of the second pre-reactor 3 include : temperature is 0-100°C, pressure is 0.1-0.5MPa, and residence time is 0.05-5h; the reaction conditions of the first reaction distillation tower 2 include: temperature is 25-75°C, pressure is 0.002-0.2MPa, residence time is 0.05-2.5h, the reaction conditions of the second reaction distillation tower 4 include: temperature is 35-85°C, pressure is 0.002-0.2MPa, residence time is 0.05-3h; the molar ratio of the stabilizer to the catalyst is 0.5-30:1.

[0104] According to a tenth embodiment of the present invention, the method for preparing peroxyacid comprises the following steps:

[0105] S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor 1, and then passing the obtained reaction product into a first reactive distillation tower 2 for reaction;

[0106] S2, passing the bottom product of the first reaction distillation tower 2 into the second pre-reactor 3 for reaction, and then passing the obtained reaction product into the second reaction distillation tower 4 for reaction;

[0107] S3, reacting the bottom product of the second reaction distillation tower 4 with a stabilizer, wherein the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline, and the catalyst is selected from one or more of sulfuric acid, nitric acid, isopolyacid and heteropolyacid; the first pre-reactor 1 and the second pre-reactor 3 are each independently selected from a microchannel reactor, a fixed bed reactor, a kettle reactor , a static mixing reactor or a membrane reactor; the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid, and the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile; based on the total weight of the organic solvent, the organic acid, the hydrogen peroxide and the catalyst as 100 weight%, the content of the organic solvent is 5-70 weight%, the content of the organic acid is 5-70 weight%, the content of the hydrogen peroxide is 5- 70% by weight, the content of the catalyst is 0.01-15% by weight; the isopoly acid is selected from one or more of decatungstic acid, heptungstic acid, octamolybdic acid and dodecamolybdic acid, and the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid; the reaction conditions of the first pre-reactor 1 include: temperature of 0-100°C, pressure of 0.1-0.5MPa, residence time of 0.05-5h, the reaction conditions of the second pre-reactor 3 include: temperature of 0-100°C, pressure of 0.1-0.5MPa, residence time of 0.0 5-5h; the reaction conditions of the first reaction distillation tower 2 include: temperature of 25-75°C, pressure of 0.002-0.2MPa, residence time of 0.05-2.5h, the reaction conditions of the second reaction distillation tower 4 include: reaction temperature of 35-85°C, reaction pressure of 0.002-0.2MPa, reaction residence time of 0.05-3h; the molar ratio of the stabilizer to the catalyst is 0.5-30:1; in step S3, the reaction conditions include: temperature of -20-65°C, time of 0.1-3h.

[0108] The following examples further illustrate the method for preparing 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.

[0109] Test Case

[0110] The analysis method of peroxides such as hydrogen peroxide and peracid refers to the national standard "Peracetic acid solution GB / T19104-2021"

[0111] The analysis methods of materials such as caprolactone and cyclohexanone refer to the industry standard "Industrial ε-caprolactone HG / T 5618-2019"

[0112] The conversion rate of cyclohexanone is calculated as follows: X = (A 环己酮的初始峰面积 -A 反应后结束后环己酮峰面积 ) / A 环己酮的初始峰面积 *100%;

[0113] The selectivity calculation formula of caprolactone: S = A 己内酯峰面积 / (A 己内酯峰面积 *C 1校正因子 +A 剩余环己酮峰面积 *C 2校正因子 +A 重组分峰面积 *C 3校正因子 ).

[0114] Embodiment and comparative example prepare the method for peroxyacid in such as Figure 1 is implemented in the system shown.

[0115] Example 1

[0116] Preparation of peroxyacid:

[0117] S1. Control the feed temperature to 25° C., continuously introduce 1.7 kg / h of propionic acid, 1.0 kg / h of hydrogen peroxide (concentration of 50 wt %), 1.0 kg / h of ethyl propionate and 0.02 kg / h of sulfuric acid (concentration of 98 wt %) into the microchannel reactor, and react at 60° C. and 0.1 MPa for 1.5 h. After the reaction, the product is introduced into a reaction distillation tower having 30 theoretical plates through the 15th theoretical plate, and 0.8 kg / h of propionic acid and 0.7 kg / h of ethyl propionate are added to the 10th theoretical plate. , and react at 50°C, 0.01MPa for 10h, the generated water and ethyl propionate form an azeotrope and enter the top of the tower, and are condensed at the top of the tower at 27°C, and phase separation is carried out in a phase separation tank, the reflux ratio is 0.34, the water phase is extracted, and ethyl propionate is refluxed to the reaction distillation tower, and the obtained product is extracted from the bottom of the tower at 63°C, the bottom distillation rate is 3.4kg / h, and the flow rate of the product is 1.983kg / h of propionic acid, 0.288kg / h of hydrogen peroxide, 0.083kg / h of water, 0.04kg / h of ethyl propionate, and 0.56kg / h of peroxypropionic acid;

[0118] S2, the product obtained in step S1 is continuously introduced into the next microchannel reactor, and reacted at 60°C, 0.1MPa for 1.5h, after the reaction is completed, the product is introduced into a reaction distillation tower provided with 30 theoretical plates through the 15th theoretical plate, and propionic acid with a flow rate of 1.5kg / h and ethyl propionate with 2kg / h are added to the 10th theoretical plate, and reacted at 50°C, 0.01MPa for 10h, the generated water and ethyl propionate form an azeotrope and enter the top of the tower, and at 1 The reaction mixture is condensed at a temperature of 5°C at the top of the tower, and phases are separated in a phase separation tank. The reflux ratio is 1, the water phase is extracted, and ethyl propionate is refluxed into a reactive distillation tower. The obtained product is extracted from the bottom of the tower at 59.4°C, and the bottom distillation rate is 2.5 kg / h. The flow rate of the product is 3.07 kg / h of propionic acid, 0.04 kg / h of hydrogen peroxide, 0.01 kg / h of water, 0.20 kg / h of ethyl propionate, 1.06 kg / h of peroxypropionic acid and 0.019 kg / h of concentrated sulfuric acid;

[0119] S3, the product obtained in step S2 is continuously introduced into a tank reactor, and pyridine with a flow rate of 0.19 kg / h is added into the reactor, and the reaction is carried out at 50° C. for 0.5 h. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide is 99.5%, and the selectivity of peroxypropionic acid is 82%.

[0120] Application Example 1

[0121] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 100 rpm, and the peroxypropionic acid solution obtained in Example 1 was slowly added dropwise to the cyclohexanone, with a molar ratio of peroxy acid to cyclohexanone of 1.02:1. The addition was completed after 0.5 h, and 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%, and the selectivity of the caprolactone was 99%.

[0122] Example 2

[0123] Preparation of peroxyacid:

[0124] S1, control the feed temperature to 30 ℃, feed flow rate of 1.7kg / h butyric acid, 1.0kg / h hydrogen peroxide (concentration of 50 weight %), 1.0kg / h acetonitrile and 0.02kg / h sulfuric acid (concentration of 98 weight %) are passed into the microchannel reactor together, and react at 10 ℃, 0.5MPa for 4.5h, after the reaction is completed, the product is passed through the 20th theoretical plate into a reaction distillation tower provided with 30 theoretical plates, and the 10th theoretical plate is supplemented with a flow rate of 0.8kg / h butyric acid and 0.7kg / h acetonitrile, and then reacted at 80 ℃, 0.1MPa for 20h, the generated water and acetonitrile form an azeotrope and enter the tower top, and condense at the tower top at 27 ℃, phase separation is carried out in a phase separation tank, the water phase is extracted, the oil phase, i.e., acetonitrile, is fully refluxed to the reaction distillation tower, and the obtained product is extracted from the bottom of the tower at 63 ℃;

[0125] S2, the bottom product of the reaction distillation tower in step S1 is continuously passed into the next microchannel reactor, and reacted at 60°C and 0.1MPa for 1.5h. After the reaction is completed, the product is passed through the 15th theoretical plate into a reaction distillation tower provided with 30 theoretical plates, and butyric acid with a flow rate of 1.5kg / h and acetonitrile with a flow rate of 2kg / h are added to the 10th theoretical plate, and then reacted at 50°C and 0.01MPa for 10h, the generated water and acetonitrile form an azeotrope and enter the top of the tower, and condensed at the top of the tower at 15°C, phase separation is performed in a phase separation tank, the reflux ratio is 1, the water phase is extracted, and the acetonitrile is refluxed to the reaction distillation tower, and the obtained product is extracted from the bottom of the tower at 59.4°C;

[0126] S3, the bottom product of the reaction distillation tower in step S2 is continuously introduced into a tank reactor, and pyridine with a flow rate of 0.15 kg / h is added into the reactor, and the reaction is carried out at 45° C. for 0.5 h. During the peroxybutyric acid process, the total conversion rate of hydrogen peroxide is 99%, and the selectivity of peroxybutyric acid is 75%.

[0127] Application Example 2

[0128] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 300 rpm, and the peroxybutyric acid solution obtained in Example 2 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxybutyric acid to cyclohexanone was 1.01:1, and the addition was completed for 0.5 h. The reaction was then allowed to stand at 45° C. and 0.3 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 98.5%, and the selectivity of the caprolactone was 97.3%.

[0129] Example 3

[0130] The method of Example 1 was followed, except that pyridine in step S3 was replaced by quinoline. During the synthesis of the peroxy acid, the total conversion rate of hydrogen peroxide was 99.5%, and the selectivity of peroxypropionic acid was 82%.

[0131] Application Example 3

[0132] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 100 rpm, and the peroxypropionic acid solution obtained in Example 3 was slowly added dropwise to the cyclohexanone, with a molar ratio of peroxypropionic acid to cyclohexanone of 1.1:1. The addition was completed after 0.5 h, and the reaction was then allowed to stand at 60° C. and 0.1 MPa for 5 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 98.9%, and the selectivity of the caprolactone was 98.5%.

[0133] Example 4

[0134] The method of Example 1 was followed, except that pyridine in step S3 was replaced by methylamine. During the synthesis of the peroxy acid, the total conversion rate of hydrogen peroxide was 99.3%, and the selectivity of peroxypropionic acid was 81%.

[0135] Application Example 4

[0136] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 200 rpm, and the peroxypropionic acid solution obtained in Example 4 was slowly added dropwise to the cyclohexanone, with a molar ratio of peroxypropionic acid to cyclohexanone of 0.9:1. The addition was completed after 0.5 h, and the reaction was then allowed to stand at 45° C. and 0.1 MPa for 5 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 88%, and the selectivity of the caprolactone was 96.5%.

[0137] Example 5

[0138] The method of Example 1 was followed, except that urea was used to replace pyridine in step S3. During the synthesis of the peroxy acid, the total conversion rate of hydrogen peroxide was 98.9%, and the selectivity of peroxypropionic acid was 81.8%.

[0139] Application Example 5

[0140] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 500 rpm, and the peroxypropionic acid solution obtained in Example 5 was slowly added dropwise to the cyclohexanone, with a molar ratio of peroxypropionic acid to cyclohexanone of 0.95:1. The addition was completed after 1.5 hours, and the reaction was then allowed to stand at 60° C. and 0.1 MPa for 4.5 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was 93%, and the selectivity of the caprolactone was 97.2%.

[0141] Example 6

[0142] The method of Example 1 was followed, except that the sulfuric acid (concentration of 98 wt%) in step S1 was replaced by nitric acid (concentration of 25 wt%). During the synthesis of the peroxy acid, the total conversion rate of hydrogen peroxide was 95.2%, and the selectivity of peroxypropionic acid was 75.9%.

[0143] Application Example 6

[0144] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 250 rpm, and the peroxypropionic acid solution obtained in Example 6 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxypropionic acid to cyclohexanone was 1.5:1, 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 98.5%, and the selectivity of the caprolactone was 88%.

[0145] Example 7

[0146] The method of Example 1 was followed, except that the sulfuric acid (concentration of 98 wt%) in step S1 was replaced by phosphotungstic acid (heteropoly acid). During the synthesis of the peroxy acid, the total conversion rate of hydrogen peroxide was 95.2%, and the selectivity of peroxypropionic acid was 65.2%.

[0147] Application Example 7

[0148] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 350 rpm, and the peroxypropionic acid solution obtained in Example 7 was slowly added dropwise to the cyclohexanone, with a molar ratio of peroxypropionic acid to cyclohexanone of 1.3:1. The addition was completed after 1.5 hours, and the reaction was then allowed to stand at 70° C. and 0.1 MPa for 2 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.7%, and the selectivity of the caprolactone was 88.2%.

[0149] Example 8

[0150] The method of Example 1 was followed, except that the sulfuric acid (concentration of 98 wt%) in step S1 was replaced by decatungstic acid (isopoly acid). During the synthesis of the peroxy acid, the total conversion rate of hydrogen peroxide was 97.1%, and the selectivity of peroxypropionic acid was 65.3%.

[0151] Application Example 8

[0152] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 450 rpm, and the peroxypropionic acid solution obtained in Example 8 was slowly added dropwise to the cyclohexanone, with a molar ratio of peroxypropionic acid to cyclohexanone of 1:1. The addition was completed after 1.5 hours, and the reaction was then allowed to stand at 60° C. and 0.2 MPa for 2 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was 98.3%, and the selectivity of the caprolactone was 97.3%.

[0153] Example 9

[0154] The method was implemented in the same manner as in Example 1, except that in step S3, pyridine was added to the reactor at a flow rate of 0.15 kg / h. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide was 99.4%, and the selectivity of peroxypropionic acid was 82.1%.

[0155] Application Example 9

[0156] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 220 rpm, and the peroxypropionic acid solution obtained in Example 9 was slowly added dropwise to the cyclohexanone for 0.5 h, and then the reaction was continued at 40° C. and 0.5 MPa for 6 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.8%, and the selectivity of the caprolactone was 94.5%.

[0157] Example 10

[0158] The method was implemented in the same manner as in Example 1, except that in step S3, pyridine was added to the reactor at a flow rate of 0.57 kg / h. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide was 99.6%, and the selectivity of peroxypropionic acid was 82.8%.

[0159] Application Example 10

[0160] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 350 rpm, and the peroxypropionic acid solution obtained in Example 10 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxypropionic acid to cyclohexanone was 1.05:1, and the addition was completed for 0.5 h. The reaction was then allowed to stand at 60° C. and 0.1 MPa for 4 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.7%, and the selectivity of the caprolactone was 99.1%.

[0161] Embodiment 11

[0162] The method of Example 1 was followed, except that the microchannel reactors in step S1 and step S2 were replaced with membrane reactors. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide was 99.1%, and the selectivity of peroxypropionic acid was 82.1%.

[0163] Application Example 11

[0164] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 100 rpm, and the peroxypropionic acid solution obtained in Example 11 was slowly added dropwise to the cyclohexanone. The addition was completed after 1.5 hours, and the reaction was continued at 35° C. and 0.1 MPa for 20 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was 98.9%, and the selectivity of the caprolactone was 97.3%.

[0165] Comparative Example 1

[0166] The method of Example 1 was followed, except that the sulfuric acid in step S1 was replaced by boric acid. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide was 65.1%, and the selectivity of peroxypropionic acid was 52.2%.

[0167] Comparative application example 1

[0168] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 60 rpm, and the peroxypropionic acid solution obtained in Comparative Example 1 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxypropionic acid to cyclohexanone was 2:1, and the addition was completed for 0.5 h, and then the reaction was stopped at 60° C. and 0.1 MPa for 3.5 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.3%, and the selectivity of the caprolactone was 28%.

[0169] Comparative Example 2

[0170] The method of Example 1 was followed, except that step S3 was omitted. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide was 99.2%, and the selectivity of peroxypropionic acid was 82.2%.

[0171] Comparative Application Example 2

[0172] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 380 rpm, and the peroxypropionic acid solution obtained in Comparative Example 2 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxypropionic acid to cyclohexanone was 1:1, and the addition was completed for 0.5 h, and then the reaction was allowed to stand at 50° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.9%, and the selectivity of the caprolactone was 15.3%.

[0173] Comparative Example 3

[0174] The method of Example 1 was followed, except that pyridine in step S3 was replaced by ethanol. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide was 99.4%, and the selectivity of peroxypropionic acid was 82.5%.

[0175] Comparative Application Example 3

[0176] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 100 rpm, and the peroxypropionic acid solution obtained in Comparative Example 3 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxypropionic acid to cyclohexanone was 1.3:1, and the addition was completed for 0.5 h, and then the reaction was stopped at 60° C. and 0.5 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 99.8%, and the selectivity of the caprolactone was 9.5%.

[0177] Comparative Example 4

[0178] The method of Example 1 is implemented, except that step S2 is not performed, and the bottom product of the first reaction distillation tower 2 in step S1 is directly reacted with the stabilizer in the mixer 5. During the synthesis of peroxypropionic acid, the total conversion rate of hydrogen peroxide is 15%, and the selectivity of peroxypropionic acid is 95.5%.

[0179] Comparative Application Example 4

[0180] 98 g of cyclohexanone was weighed and placed in a tank reactor, and the temperature was raised to 50° C. The magnetic stirring was turned on at a stirring speed of 250 rpm, and the peroxypropionic acid solution obtained in Comparative Example 4 was slowly added dropwise to the cyclohexanone, the molar ratio of peroxypropionic acid to cyclohexanone was 1:1, and the addition was completed for 0.5 h, and then the reaction was allowed to stand at 60° C. and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 98.8%, and the selectivity of the caprolactone was 6.3%.

[0181] Table 1

[0182]

[0183] As can be seen from Table 1, the method of the present invention is used to prepare the peracid solution, which can improve the selectivity and yield of the peracid, so that the total conversion rate of hydrogen peroxide is greater than 95%, and the selectivity of the peracid is greater than 65%. At the same time, the peracid solution is used to oxidize cyclohexanone to prepare caprolactone, and the conversion rate of cyclohexanone is greater than 85%, and the selectivity of the obtained caprolactone is greater than 85%.

[0184] 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 method for preparing peroxyacid, characterized in that: The method comprises the following steps: S1, reacting an organic acid, hydrogen peroxide, a catalyst and a solvent in a first pre-reactor (1), and then passing the obtained reaction product into a first reactive distillation tower (2) for reaction; S2, passing the bottom product of the first reaction distillation tower (2) into a second pre-reactor (3) for reaction, and then passing the obtained reaction product into a second reaction distillation tower (4) for reaction; S3, reacting the bottom product of the second reaction distillation tower (4) with a stabilizer, Wherein, the stabilizer is a nitrogen-containing basic compound, and the N atom has a lone pair of electrons. The catalyst is selected from one or more of sulfuric acid, nitric acid, isopoly acid and heteropoly acid.

2. The method according to claim 1, characterized in that The stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, lutidine, pyrrole, indole, acridine, carbazole and quinoline.

3. The method according to claim 1 or 2, characterized in that: The molar ratio of the stabilizer to the catalyst is 0.5-30:

1.

4. The method according to any one of claims 1 to 3, characterized in that: The first pre-reactor (1) and the second pre-reactor (3) are each independently selected from a microchannel reactor, a fixed bed reactor, a tank reactor, a static mixing reactor or a membrane reactor.

5. The method according to any one of claims 1 to 4, characterized in that: The organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid; Preferably, the solvent is selected from one or more of ethyl acetate, propyl acetate, isobutyl acetate, cyclohexane, benzene, propyl propionate, isopropyl propionate, ethyl propionate, butyl acetate, n-ethane, dichloromethane and acetonitrile.

6. The method according to any one of claims 1 to 5, characterized in that: In step S1, based on the total weight of the solvent, organic acid, hydrogen peroxide and catalyst as 100 weight %, the content of the solvent is 5-70 weight %, the content of the organic acid is 5-70 weight %, the content of the hydrogen peroxide is 5-70 weight %, and the content of the catalyst is 0.01-15 weight %.

7. The method according to any one of claims 1 to 6, characterized in that: The isopoly acid is selected from one or more of decatungstic acid, heptungstic acid, octamolybdic acid and dodecamolybdic acid; Preferably, the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid and silicotungstic acid.

8. The method according to any one of claims 1 to 7, characterized in that: The concentration of peroxyacid in the solution obtained by the reaction in step S3 is 5-35% by weight.

9. The method according to any one of claims 1 to 8, characterized in that: The reaction conditions of the first pre-reactor (1) include: temperature of 0-100°C, pressure of 0.1-0.5MPa, and residence time of 0.05-5h; Preferably, the reaction conditions of the second pre-reactor (3) include: temperature of 0-100°C, pressure of 0.1-0.5 MPa, and residence time of 0.05-5h.

10. The method according to any one of claims 1 to 9, characterized in that: The reaction conditions of the first reactive distillation tower (2) include: temperature of 25-75°C, pressure of 0.002-0.2MPa, and residence time of 0.05-2.5h; Preferably, the reaction conditions of the second reactive distillation tower (4) include: temperature of 35-85°C, pressure of 0.002-0.2 MPa, and residence time of 0.05-3 h.

11. The method according to any one of claims 1 to 10, characterized in that: In step S3, the reaction conditions include: temperature of -20-65°C and time of 0.1-3h.

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