A catalyst composition and a method of making a peroxy acid

Abstract

The application belongs to the technical field of chemical product production, and particularly relates to a catalyst composition and a method for preparing peroxy acid. The catalyst composition contains an acidic catalyst and a stabilizer, wherein the stabilizer is a nitrogen-containing alkaline compound with a lone pair of electrons on the N atom. The specific catalyst composition can be used to prepare peroxy acid, and the conversion rate of hydrogen peroxide is greater than 95%, the selectivity of the prepared peroxy acid is greater than 70%, and the final obtained peroxy acid product is used to prepare caprolactone, so that the conversion rate of cyclohexanone is greater than 95%, and the selectivity of the prepared caprolactone is greater than 95%.

Description

Technical Field

[0001] This invention relates to the field of chemical product manufacturing technology, specifically to a catalyst composition and a method for preparing peroxyacid. Background Technology

[0002] Peroxyacid is a high-performance oxidant that can be used as a highly effective disinfectant or sterilizer in daily life, as well as a bleaching agent for bleaching textiles, paper, paraffin and oils. Industrially, it is mainly used to oxidize cyclohexanone to produce caprolactone.

[0003] The synthesis reaction of peroxyacids is RCOOH + H₂O₂ → RCOOOH + H₂O. This reaction is a nucleophilic reaction. Due to the weak affinity of hydrogen peroxide, it is difficult for it to undergo nucleophilic reactions with the carbonyl positions of organic acids, resulting in limited reaction kinetics and a low reaction rate. In the production of peroxyacids, heteropoly acids, nitric acid, and sulfuric acid are usually used as catalysts to improve reaction efficiency.

[0004] Since the peroxy acid synthesis reaction is a homogeneous reaction, the acidic catalyst remains in the product solution and cannot be separated. The residual catalyst will affect the quality of the peroxy acid product. For example, when it is used to synthesize caprolactone, the residual protic acid catalyst will promote the condensation of caprolactone, which will greatly reduce the selectivity of the reaction (Note: here it mainly refers to peroxypropionic acid and peroxy acids with higher molecular weight. In fact, peroxyformic acid and peracetic acid have lower boiling points and can be extracted from the top of the column by distillation. The remaining catalyst is extracted from the bottom of the column). When the peroxy acid does not contain a strong acid catalyst, its selectivity is higher when synthesizing caprolactone. The reaction process is shown in formula (1). However, when the peroxy acid contains a strong acid catalyst, its selectivity is lower when synthesizing caprolactone. Caprolactone will generate various isomerization products and various oligomers such as dimers and trimers.

[0005]

[0006] Patent application CN1034500C discloses a method for synthesizing peroxypropionic acid using boric acid as a catalyst. Boric acid is a weak acid, and its influence on downstream caprolactone synthesis is also relatively weak, resulting in minimal side reactions. However, the weak acidity of boric acid limits the synthesis efficiency of peroxyacid. Patent application CN103570667A discloses a continuous method for preparing caprolactone. This method uses boric acid as a catalyst and hydrogen peroxide as an oxidant, continuously oxidizing organic carboxylic acids in multiple reactive distillation columns to obtain peroxyacid. The peroxyacid is then continuously introduced into multiple stirred tanks connected in series for reaction to obtain a caprolactone solution. While boric acid, being a weak acid, has a relatively small impact on caprolactone polymerization, its catalytic efficiency for peroxyacid synthesis is low. The series connection of multiple reactive distillation columns increases energy consumption and is also unfavorable for industrial production. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies in peroxyacid oxidation processes, such as low peroxyacid synthesis efficiency and the presence of residual acidic catalyst in the peroxyacid feed solution. This leads to low selectivity and reduced yield of caprolactone when the peroxyacid feed solution is used to oxidize cyclohexanone. Therefore, this invention proposes a catalyst composition and a method for preparing peroxyacid. This composition incorporates an acidic catalyst to promote peroxyacid synthesis, and also includes a specific alkaline stabilizer to obtain a stable peroxyacid product. Using this specific catalyst composition, the conversion rate of hydrogen peroxide can be >95%, and the selectivity of the prepared peroxyacid can be >70%. The final peroxyacid product is then used to prepare caprolactone, achieving a cyclohexanone conversion rate >95% and a caprolactone selectivity >95%.

[0008] The first aspect of the present invention provides a catalyst composition comprising an acidic catalyst and a stabilizer, wherein the acidic catalyst and the stabilizer are stored independently, wherein the stabilizer is a nitrogen-containing basic compound and the N atom has a lone pair of electrons.

[0009] Preferably, the molar ratio of the stabilizer to the acidic catalyst is 1 to 30:1, more preferably 3 to 10:1.

[0010] Preferably, the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, dimethylpyridine, pyrrole, indole, acridine, carbazole and quinoline.

[0011] Preferably, the acidic catalyst is selected from one or more of sulfuric acid, nitric acid, heteropolyacids, and isopolyacids. More preferably, the heteropolyacid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid. Even more preferably, the isopolyacid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid, and dodecamolybdic acid.

[0012] A second aspect of the present invention provides a method for preparing peroxyacid, the method utilizing the peroxyacid composition described above, the method comprising the following steps:

[0013] (1) Mix organic solvent, organic acid, hydrogen peroxide and acidic catalyst to obtain peroxy acid synthesis solution;

[0014] (2) The peroxy acid synthesis solution is reacted with a stabilizer;

[0015] The stabilizer is a nitrogen-containing basic compound, and the N atom has a lone pair of electrons.

[0016] Preferably, the molar ratio of the stabilizer to the acidic catalyst is 1 to 30:1, more preferably 3 to 10:1.

[0017] Preferably, the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, dimethylpyridine, pyrrole, indole, acridine, carbazole and quinoline.

[0018] Preferably, the acidic catalyst is selected from one or more of sulfuric acid, nitric acid, heteropolyacids, and isopolyacids. More preferably, the heteropolyacid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid. Even more preferably, the isopolyacid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid, and dodecamolybdic acid.

[0019] Preferably, based on the total weight of the organic solvent, organic acid, hydrogen peroxide, and acidic catalyst (100% by weight), the content of the organic solvent is 5-70% by weight, and the content of the organic acid is...

[0020] The content of hydrogen peroxide is 5-70% by weight, and the content of acidic catalyst is 0.01-15% by weight. More preferably, based on the total weight of the organic solvent, organic acid, hydrogen peroxide, and acidic catalyst as 100% by weight, the content of the organic solvent is 10-50% by weight, the content of the organic acid is 10-50% by weight, the content of hydrogen peroxide is 10-60% by weight, and the content of acidic catalyst is 0.05-10% by weight.

[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-hexane, dioxane, dichlorohexane, cyclohexane, benzene, and acetonitrile.

[0022] Preferably, the organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid.

[0023] Preferably, in step (1), the mixing conditions include: a temperature of 0 to 130°C, a time of 0.05 to 30 h, and an absolute pressure of 0.001 to 1 MPa.

[0024] Preferably, the concentration of peroxy acid in the peroxy acid synthesis solution is 5-50% by weight.

[0025] Preferably, in step (2), the reaction conditions include: a temperature of 10 to 50°C, a time of 0.2 to 1.5 h, and an absolute pressure of 0.1 to 0.3 MPa.

[0026] Preferably, the concentration of the hydrogen peroxide is 10-80% by weight, more preferably 25-50% by weight.

[0027] The catalyst composition of this invention combines a specific catalyst with a specific stabilizer, utilizing the principle of neutralization or complexation reaction between the catalyst and the stabilizer. Then, according to the method described in this invention, the catalyst composition is applied to a process for preparing peroxyacid. First, a composition containing a specific organic solvent, organic acid, hydrogen peroxide, and acidic catalyst is reacted under certain conditions to obtain a peroxyacid synthesis solution. Then, the synthesis solution is further reacted with a specific stabilizer to eliminate H+ in the synthesis solution. + The concentration of hydrogen peroxide is increased to improve the quality and stability of the peroxy acid product, resulting in a hydrogen peroxide conversion rate >95% and a peroxy acid selectivity >70%. This peroxy acid is then used to prepare caprolactone, resulting in a cyclohexanone conversion rate >95% and a caprolactone selectivity >95%. Detailed Implementation

[0028] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0029] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] The first aspect of the present invention provides a catalyst composition comprising an acidic catalyst and a stabilizer, wherein the acidic catalyst and the stabilizer are stored independently, wherein the stabilizer is a nitrogen-containing basic compound and the N atom has a lone pair of electrons.

[0031] To ensure that the selectivity of the prepared peroxy acid product is >70%, and to use this peroxy acid in the preparation of caprolactone, achieving a cyclohexanone conversion >95% and a caprolactone selectivity >95%, the amounts of the stabilizer and the acidic catalyst need to be controlled within a certain range. In a specific embodiment, the molar ratio of the stabilizer to the acidic catalyst is 1–30:1. In a preferred embodiment, the ratio of the stabilizer to the acidic catalyst is 3–10:1, for example, 3:1, 4:1, 5:1, or 6:1.

[0032] 1, 7:1, 8:1, 9:1 or 10:1.

[0033] To eliminate residual acidic solution during peroxyacid synthesis and improve the stability and quality of peroxyacid products, in the composition of this invention, in specific embodiments, the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, dimethylpyridine, pyrrole, indole, acridine, carbazole, and quinoline. In this document, the heterocyclic compounds in the stabilizer include, but are not limited to, the heterocyclic compounds described above, and may include substitutions of various functional groups. In a preferred embodiment, the stabilizer is selected from one or more of pyridine, aniline, ethylamine, isopropylamine, and ethanolamine.

[0034] To improve the synthesis efficiency of peroxy acids and optimize the quality and stability of peroxy acid products, in the composition described in this invention, in a specific embodiment, the acidic catalyst can be a catalyst that releases H+. + The protic acid. In a preferred embodiment, the acidic catalyst is selected from one or more of sulfuric acid, nitric acid, heteropolyacids and isopolyacids, and specifically, boric acid and / or metaboric acid may be optionally added.

[0035] In the compositions described in this invention, in specific embodiments, the heteropolyacids and isopolyacids can be conventional choices in the art and may include elemental modification and doping. Hereinafter, the heteropolyacid refers to a polyoxometalate formed by the condensation of different types of oxyacid ions, and the isopolyacid refers to a metal oxometalate formed by the condensation of the same type of oxyacid ion. In preferred embodiments, the heteropolyacid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid, and the isopolyacid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid, and dodecamolybdic acid.

[0036] A second aspect of the present invention provides a method for preparing peroxyacid, the method comprising the following steps:

[0037] (1) Mix organic solvent, organic acid, hydrogen peroxide and acidic catalyst to obtain peroxy acid synthesis solution;

[0038] (2) The peroxy acid synthesis solution is reacted with a stabilizer;

[0039] The stabilizer is a nitrogen-containing basic compound, and the N atom has a lone pair of electrons.

[0040] In the method described in this invention, to improve the quality and stability of the peroxy acid product, ensuring that the selectivity of the prepared peroxy acid is >70%, and using this peroxy acid to prepare caprolactone, achieving a cyclohexanone conversion rate >95% and a caprolactone selectivity >95%, in a specific embodiment, the molar ratio of the stabilizer to the acidic catalyst is 1–30:1. In a preferred embodiment, the molar ratio of the stabilizer to the acidic catalyst is 3–10:1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1.

[0041] To improve the synthesis efficiency of peroxy acids and optimize the quality of peroxy acid products, in the method described in this invention, in a specific embodiment, the acidic catalyst can be a catalyst that releases H+. + The protic acid. In a preferred embodiment, the acidic catalyst is selected from one or more of sulfuric acid, nitric acid, heteropolyacids and isopolyacids, and specifically, boric acid and / or metaboric acid may be optionally added.

[0042] In the method described in this invention, in specific embodiments, the heteropolyacid and the isopolyacid can be conventional choices in the art, and may include elemental modification and doping. In a preferred embodiment, the heteropolyacid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid. In a more preferred embodiment, the isopolyacid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid, and dodecamolybdic acid.

[0043] To eliminate residual acidic solution during the synthesis of peroxyacid and improve the stability and quality of the peroxyacid product, in the method described in this invention, in specific embodiments, the stabilizer is selected from one or more of methylamine, ethylamine, triethylamine, trimethylamine, ethylenediamine, urea, ethanolamine, isopropylamine, tert-butylamine, aniline, benzylamine, cyclohexylamine, pyridine, dimethylpyridine, pyrrole, indole, acridine, carbazole, and quinoline. In a preferred embodiment, the stabilizer is selected from one or more of pyridine, aniline, ethylamine, isopropylamine, and ethanolamine.

[0044] To improve the conversion rate of hydrogen peroxide in the synthesis of peroxyacid and to improve the quality of the peroxyacid product, the ratio of the organic solvent, organic acid, hydrogen peroxide, and acidic catalyst should be controlled within a certain range. In the method of this invention, in a specific embodiment, based on the total weight of the organic solvent, organic acid, hydrogen peroxide, and acidic 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 acidic catalyst is 0.01-15% by weight.

[0045] In the method of the present invention, in a preferred embodiment, based on the total weight of the organic solvent, organic acid, hydrogen peroxide and acidic catalyst as 100% by weight, the content of the organic solvent is 10-50% by weight, the content of the organic acid is 10-50% by weight, the content of the hydrogen peroxide is 10-60% by weight, and the content of the acidic catalyst is 0.05-10% by weight.

[0046] In the method described in this invention, in order to form an azeotrope with water and, upon cooling, form an oil-water two-phase solvent to facilitate solvent separation and recovery, 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-hexane, dioxane, dichlorohexane, cyclohexane, benzene, and acetonitrile. In a preferred embodiment, the organic solvent is selected from one or more of dichlorohexane, ethyl propionate, cyclohexane, and benzene.

[0047] In the method described in this invention, in specific embodiments, as long as the organic acid is in the liquid phase or soluble in a solvent, it can be an organic acid with relatively high acidity in the art. In a preferred embodiment, the organic acid is selected from one or more of formic acid, acetic acid, propionic acid, and butyric acid.

[0048] In the method described in this invention, in a specific embodiment, the hydrogen peroxide is a conventional oxidizing solvent. In a preferred embodiment, the concentration of the hydrogen peroxide is 10-80% by weight. In a more preferred embodiment, the concentration of the hydrogen peroxide is 25-50% by weight, for example, 25%, 30%, 40%, or 50% by weight.

[0049] In the method described in this invention, in a specific embodiment, in step (1), the organic solvent, organic acid, hydrogen peroxide, and acidic catalyst can be introduced into the reactor separately and then mixed with other materials. In a preferred embodiment, the organic solvent, organic acid, hydrogen peroxide, and acidic catalyst can be mixed in pairs and then mixed with other materials.

[0050] In the method described in this invention, in a specific embodiment, the mixing conditions in step (1) include: a temperature of 0 to 130°C, a reaction residence time of 0.05 to 30 h, and an absolute pressure of 0.001 to 1 MPa.

[0051] In the method described in this invention, in a specific embodiment, the reactor used in step (1) can be a microchannel reactor, a fixed-bed reactor, a batch reactor, a reactive distillation column, a static mixing reactor, or a membrane reactor. In a preferred embodiment, the reactor used in the method can be one of the reactors described in the specific embodiment, or a combination of multiple reactors. In a more preferred embodiment, the reaction process in the reactor is batch or continuous.

[0052] In the method described in this invention, in a specific embodiment, in step (1), when the reactor used for the reaction is a microchannel reactor, a fixed-bed reactor, a batch reactor, a reactive distillation column, a static mixing reactor, or a membrane reactor, the reaction temperature is 35 to 80°C in order to increase the reaction rate and avoid the decomposition of peroxy acid and hydrogen peroxide.

[0053] In the method described in this invention, in a specific embodiment, in step (1), when the reactor used for the reaction is a distillation column or a reactive distillation column, the temperature of the column section containing hydrogen peroxide and peroxy acid is 35 to 85°C.

[0054] In the method described in this invention, in a specific embodiment, in step (1), when the reactor used for the reaction is a microchannel reactor, a fixed-bed reactor, a batch reactor, or a static mixing reactor, the absolute pressure of the reaction is 0.01 to 1 MPa, preferably 0.05 to 0.5 MPa.

[0055] In the method described in this invention, in a specific embodiment, in step (1), when the reactor used for the reaction is a distillation column or a reactive distillation column, the absolute pressure of the reaction is 0.001 to 0.5 MPa, preferably 0.002 to 0.2 MPa.

[0056] In the method described in this invention, in a preferred embodiment, under preferred material formulation and reaction conditions, the reaction residence time can also be controlled within a certain range, and the selectivity and efficiency of the prepared peroxy acid will be improved. In step (1), the reaction residence time is 0.1 to 10 h.

[0057] In the method described in this invention, in a specific embodiment, in step (1), the concentration of peroxy acid in the peroxy acid synthesis solution is 5 to 50% by weight, for example, it can be 5% by weight, 10% by weight, 20% by weight, 30% by weight, 40% by weight, 45% by weight or 50% by weight.

[0058] In the method described in this invention, in a specific embodiment, in step (1), the peroxy acid synthesis solution can be either an aqueous peroxy acid or an anhydrous peroxy acid. In this text, aqueous peroxy acid refers to peroxy acid products where water is not separated; the water includes water introduced by the raw hydrogen peroxide, water generated during the reaction, and water added to adjust the concentration of the diluted product. Anhydrous peroxy acid refers to peroxy acid products where water has been removed; the removed water includes water introduced by the hydrogen peroxide and water generated during the reaction. There are no special requirements for the dehydration method; it can be removed by azeotropic distillation, membrane separation, or adsorption using adsorption materials. The water content in the dehydrated product is less than 0.9% by weight.

[0059] In the method described in this invention, in a specific embodiment, the reaction conditions in step (2) include: a temperature of -20 to 70°C, for example, -20°C, 0°C, 25°C, 30°C, 40°C, 50°C, 55°C, 60°C, or 70°C; a time of 0.1 to 10 hours, for example, 0.1 hours, 0.2 hours, 0.5 hours, 1 hour, 2 hours, 5 hours, or 10 hours; and an absolute pressure of 0 to 0.5 MPa, for example, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, or 0.5 MPa.

[0060] In the method of the present invention, in a preferred embodiment, the reaction conditions in step (2) include: a temperature of 0–70°C, a time of 0.1–3 h, and an absolute pressure of 0.1–0.5 MPa. In a more preferred embodiment, the reaction conditions in step (2) include: a temperature of 10–50°C, a time of 0.2–1.5 h, and an absolute pressure of 0.1–0.3 MPa.

[0061] In the method of the present invention, in step (2), during the specific operation, the stabilizer is added to the peroxy acid synthesis solution under stirring conditions. Specifically, the stirring conditions include a speed of 10 to 600 rpm and a time of 0.1 to 10 h.

[0062] In the method described in this invention, during the specific operation process, the peroxyacid solution obtained in step (2) is stored at 0°C, and the daily decomposition rate of the peroxyacid is less than 0.05%.

[0063] In the method described in this invention, in a specific embodiment, the pH value of the solution obtained in step (2) is -1 to 3, for example, it can be -1, 0.1, 1, 2, 2.5 or 3.

[0064] In the method described in this invention, caprolactone is prepared by reacting the peroxy acid solution obtained in step (2) with cyclohexanone. In the specific operation process, cyclohexanone is first stirred at a temperature of 10-80°C, and the peroxy acid solution is slowly added dropwise at a stirring speed of 10-600 rpm. After the peroxy acid solution is added dropwise, the mixture of the peroxy acid solution and the cyclohexanone is reacted at 10-80°C and 0.1-0.5 MPa for 1-10 h. Specifically, the molar ratio of peroxy acid to cyclohexanone in the peroxy acid solution is 0.5-3:1.

[0065] The following examples further illustrate the method for preparing peroxyacid according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0066] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0067] Phosphotungstic acid: Purchased from Sinopharm Reagent, product purity > 99.9%;

[0068] Decatungstic acid: Purchased from Sinopharm Reagent, product purity > 99.9%;

[0069] Pyridine: Purchased from Sinopharm Reagent, product purity > 99.9%;

[0070] Cyclohexanone: Purchased from Sinopharm Reagent Co., Ltd., product purity > 99.9%.

[0071] Test example:

[0072] For the analysis methods of peroxides such as hydrogen peroxide and peroxyacid, refer to the national standard "Peracetic Acid Solution GB / T19104-2021";

[0073] For analytical methods of materials such as caprolactone and cyclohexanone, refer to the industry standard "Industrial ε-caprolactone HG / T 5618-2019";

[0074] The formula for calculating the conversion rate of cyclohexanone is: 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%;

[0075] The formula for calculating the selectivity of caprolactone is: 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)*100%.

[0076] Example 1

[0077] (1) Weigh 150g of ethyl propionate, 150g of propionic acid and 100g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 0.5g of phosphotungstic acid (heteropoly acid) to the reaction vessel and react at 70℃ and 0.1MPa absolute pressure for 1h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0078] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and 0.04 g of pyridine (stabilizer) was added at a stirring speed of 100 rpm to make the molar ratio of pyridine to phosphotungstic acid (heteropolyacid) 3:1. After the addition of pyridine was completed, the mixture of peroxypropionic acid synthesis solution and pyridine was reacted at 50 °C and an absolute pressure of 0.1 MPa for 1 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.3%, the selectivity of peroxypropionic acid was 92%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 31.1%.

[0079] Application Example 1

[0080] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxypropionic acid solution obtained in Example 1 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and an absolute pressure of 0.1 MPa for 5 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 99.9%, and the selectivity of caprolactone was 98%.

[0081] Example 2

[0082] (1) Weigh 150g of ethyl propionate, 150g of propionic acid and 100g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 0.5g of phosphomolybdic acid (heteropoly acid) to the reaction vessel and react at 70℃ and 0.1MPa absolute pressure for 1h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0083] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and pyridine was added at a stirring speed of 300 rpm to make the molar ratio of pyridine to phosphomolybdic acid (heteropoly acid) 10:1. After the addition of pyridine was completed, the mixture of peroxypropionic acid synthesis solution and pyridine was reacted at 25°C and an absolute pressure of 0.1 MPa for 1 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.2%, the selectivity of the peroxypropionic acid solution was 84%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 28.4%.

[0084] Application Example 2

[0085] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 50 rpm, and the peroxypropionic acid solution obtained in Example 2 was slowly added dropwise to the cyclohexanone. The molar ratio of peroxypropionic acid to cyclohexanone was 1.05:1. The addition was completed after 0.5 hours. The reaction was then maintained at 65°C and an absolute pressure of 0.1 MPa for 4.5 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 99.9%, and the selectivity of caprolactone was 97%.

[0086] Example 3

[0087] (1) Weigh 150g of ethyl propionate, 40.05g of propionic acid and 200.25g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 10g of decatungstic acid (isopolyacid) to the reaction vessel and react at 70℃ and 0.1MPa absolute pressure for 1h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0088] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and quinoline (stabilizer) was added at a stirring speed of 100 rpm to make the molar ratio of quinoline to decatungstic acid (isopolyacid) 30:1. After the addition of quinoline was completed, the mixture of peroxypropionic acid synthesis solution and quinoline was reacted at 50°C and an absolute pressure of 0.15 MPa for 1 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.3%, the selectivity of the peroxypropionic acid solution was 75%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 25.3%.

[0089] Application Example 3

[0090] 100g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 300 rpm, and the peroxypropionic acid solution obtained in Example 3 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then maintained at 65°C and an absolute pressure of 0.4 MPa for 2 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 97.5%, and the selectivity of caprolactone was 98%.

[0091] Example 4

[0092] The procedure was carried out as described in Example 1, except that in step (1), 0.5 g of sulfuric acid (98 wt%) was added to the reactor and the reaction was carried out at 0°C and an absolute pressure of 0.5 MPa for 15 h. In step (2), the stabilizer was replaced with aniline, and the molar ratio of aniline to sulfuric acid (acidic catalyst) was 15:1. The specific operation process includes the following steps:

[0093] (1) Weigh 150g of ethyl propionate, 150g of propionic acid and 100g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 0.5g of sulfuric acid (98wt%) to the reaction vessel and react at 0℃ and 0.5MPa for 15h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0094] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and 7.17 g of aniline (stabilizer) was added at a stirring speed of 200 rpm, so that the molar ratio of aniline to sulfuric acid (acidic catalyst) was 15:1. After the addition of aniline was completed, the mixture of peroxypropionic acid synthesis solution and aniline was reacted at 60 °C and an absolute pressure of 0.5 MPa for 1 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.5%, the selectivity of the peroxypropionic acid solution was 90%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 30.4%.

[0095] Application Example 4

[0096] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 300 rpm. The molar ratio of peroxypropionic acid to cyclohexanone was 1.03:1. The peroxypropionic acid solution obtained in Example 4 was slowly added dropwise to the cyclohexanone, and the addition was completed after 0.5 hours. The reaction was then maintained at 50°C and an absolute pressure of 0.1 MPa for 4 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 99.9%, and the selectivity of caprolactone was 99.8%.

[0097] Example 5

[0098] The procedure was carried out as described in Example 1, except that in step (1), 0.5 g of phosphotungstic acid (heteropolyacid) was added to the reactor and reacted at 130°C and 1 MPa absolute pressure for 20 h, and the stabilizer was replaced with ethanolamine. The specific operation process includes the following steps:

[0099] (1) Weigh 150g of ethyl propionate, 150g of propionic acid and 100g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 0.5g of phosphotungstic acid (heteropoly acid) to the reaction vessel and react at 13℃ and 1MPa absolute pressure for 20h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0100] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and ethanolamine (stabilizer) was added at a stirring speed of 300 rpm to make the molar ratio of ethanolamine to phosphotungstic acid (heteropolyacid) 6:1. After the addition of ethanolamine was completed, the mixture of peroxypropionic acid synthesis solution and ethanolamine was reacted at 70°C and an absolute pressure of 0.5 MPa for 1 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.2%, the selectivity of the peroxypropionic acid solution was 85%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 28.7%.

[0101] Application Example 5

[0102] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 350 rpm, and the peroxypropionic acid solution obtained in Example 5 was slowly added dropwise to the cyclohexanone, wherein the molar ratio of peroxypropionic acid to cyclohexanone was 1.02:1. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and an absolute pressure of 0.1 MPa for 5.5 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 99.3%, and the selectivity of caprolactone was 98%.

[0103] Example 6

[0104] The procedure is carried out in accordance with Example 1, except that in step (1), the reaction conditions in the reactive distillation column and the molar ratio of stabilizer to acid catalyst are adjusted. The specific operation includes the following steps:

[0105] (1) Weigh 150g of ethyl propionate, 150g of propionic acid and 100g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 0.5g of phosphotungstic acid (heteropoly acid) to the reaction vessel and react at 70℃ and 0.1MPa absolute pressure for 1h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 70℃, the top temperature to 27℃, and the absolute pressure to 0.01MPa. During the reaction, the reaction is held for 5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0106] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and 0.08 g of pyridine (stabilizer) was added at a stirring speed of 100 rpm to make the molar ratio of pyridine to phosphotungstic acid (heteropolyacid) 6:1. After the addition of pyridine was completed, the mixture of peroxypropionic acid synthesis solution and pyridine was reacted at 55°C and an absolute pressure of 0.1 MPa for 1 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.7%, the selectivity of the peroxypropionic acid solution was 95%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 32.1%.

[0107] Application Example 6

[0108] 50g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxypropionic acid solution obtained in Example 6 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then allowed to proceed at 55°C and 0.1 MPa for 5.5 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 99.8%, and the selectivity of caprolactone was 97.8%.

[0109] Example 7

[0110] The procedure is carried out in accordance with Example 1, except that ethyl propionate is replaced with acetonitrile, propionic acid is replaced with butyric acid, and heteropolyacid is replaced with nitric acid. The specific operation includes the following steps:

[0111] (1) Weigh out 150g of acetonitrile, 150g of butyric acid and 100g of hydrogen peroxide (90wt%) and place them in a reaction vessel. Add 0.5g of nitric acid (25wt%) to the reaction vessel. The reaction was carried out at 35°C and 0.1 MPa for 1 hour to obtain an aqueous peroxybutyric acid product. The aqueous peroxyacetic acid product was then placed in a reactive distillation column with the bottom temperature set to 80°C, the top temperature set to 35°C, and the absolute pressure set to 0.015 MPa. During the reaction, the reaction was held for 1.5 hours. Acetonitrile and water formed an azeotrope and entered the top condenser. The condensed material was in the form of an oil-water two-phase mixture. Acetonitrile was completely refluxed as the oil phase, and the aqueous phase was completely collected. The resulting anhydrous peroxyacetic acid product was collected from the bottom of the column to obtain a peroxybutyric acid synthesis solution.

[0112] (2) The peroxybutyric acid synthesis solution obtained in step (1) was placed in a batch reactor, and pyridine (stabilizer) was added at a stirring speed of 100 rpm to make the molar ratio of pyridine to nitric acid 3:1. After the addition of pyridine was completed, the mixture of peroxybutyric acid synthesis solution and pyridine was reacted at 50°C and an absolute pressure of 0.1 MPa for 1 h to obtain a peroxybutyric acid solution. The conversion rate of hydrogen peroxide was calculated to be 98%, the selectivity of the peroxybutyric acid solution was 74%, and the concentration of peroxypropionic acid in the peroxybutyric acid solution was 25%.

[0113] Application Example 7

[0114] 50g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxybutyric acid solution obtained in Example 7 was slowly added dropwise to the cyclohexanone at a molar ratio of 1:1. The addition was completed after 2.5 hours, and the reaction was then maintained at 55°C and an absolute pressure of 0.1 MPa for 5 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 98.3%, and the selectivity of caprolactone was 98%.

[0115] Example 8

[0116] The procedure is carried out in accordance with Example 1, except that the reaction conditions between the peroxypropionic acid synthesis solution and the stabilizer in step (2) are changed. The specific operation includes the following steps:

[0117] (1) Weigh 150g of ethyl propionate, 150g of propionic acid and 100g of hydrogen peroxide (50wt%) and place them in a reaction vessel. Add 0.5g of phosphotungstic acid (heteropoly acid) to the reaction vessel and react at 70℃ and 0.1MPa absolute pressure for 1h to obtain a water-containing peroxypropionic acid product. Then place the water-containing peroxypropionic acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Ethyl propionate and water form an azeotrope and enter the top condenser. The condensed material is an oil-water two-phase mixture. Ethyl propionate is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxypropionic acid synthesis solution.

[0118] (2) The peroxypropionic acid synthesis solution obtained in step (1) was placed in a batch reactor, and 0.04 g of pyridine (stabilizer) was added at a stirring speed of 100 rpm to make the molar ratio of pyridine to phosphotungstic acid (heteropolyacid) 3:1. After the addition of pyridine was completed, the mixture of peroxypropionic acid synthesis solution and pyridine was reacted at 30°C and an absolute pressure of 0.1 MPa for 0.2 h to obtain a peroxypropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.3%, the selectivity of the peroxypropionic acid solution was 92%, and the concentration of peroxypropionic acid in the peroxypropionic acid solution was 31.1%.

[0119] Application Example 8

[0120] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxypropionic acid solution obtained in Example 8 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and an absolute pressure of 0.1 MPa for 2 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 99.9%, and the selectivity of caprolactone was 96.7%.

[0121] Example 9

[0122] The procedure is carried out as described in Example 7, except that, based on the total weight of acetonitrile, butyric acid, hydrogen peroxide, and nitric acid as 100% by weight, the content of acetonitrile is 50% by weight, the content of butyric acid is 35% by weight, the content of hydrogen peroxide is 10% by weight, and the content of nitric acid is 5% by weight. The specific operation process includes the following steps:

[0123] (1) Weigh 205g acetonitrile, 143.5g butyric acid and 41g hydrogen peroxide (80wt%) and place them in a reaction vessel. Add 10.5g nitric acid (25wt%) to the reaction vessel and react at 70℃ and 0.1MPa for 1h to obtain a water-containing peroxybutyric acid product. Then place the water-containing peroxybutyric acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 80℃, the top temperature to 35℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 1.5h. Acetonitrile and water form an azeotrope and enter the top condenser. The condensed material is in the form of an oil-water two-phase mixture. Acetonitrile is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxybutyric acid synthesis solution.

[0124] (2) The peroxybutyric acid synthesis solution obtained in step (1) was placed in a batch reactor, and pyridine (stabilizer) was added at a stirring speed of 100 rpm to make the molar ratio of pyridine to nitric acid 10:1. After the addition of pyridine was completed, the mixture of peroxybutyric acid synthesis solution and pyridine was reacted at 50°C and an absolute pressure of 0.1 MPa for 1 h to obtain a peroxybutyric acid solution. The conversion rate of hydrogen peroxide was calculated to be 99%, the selectivity of the peroxybutyric acid solution was 70%, and the concentration of peracetic acid in the peroxypropionic acid solution was 23.6%.

[0125] Application Example 9

[0126] 50g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxybutyric acid solution obtained in Example 9 was slowly added dropwise to the cyclohexanone. The molar ratio of peroxybutyric acid to cyclohexanone was 0.95:1. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and an absolute pressure of 0.1 MPa for 2 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 97.9%, and the selectivity of caprolactone was 97.6%.

[0127] Example 10

[0128] The procedure is carried out as described in Example 7, except that in step (1), the reaction conditions in the reactor and the reactive distillation column, as well as the molar ratio of stabilizer to acid catalyst, are adjusted. The specific operation includes the following steps:

[0129] (1) Weigh 150g acetonitrile, 150g butyric acid and 100g hydrogen peroxide (90wt%) and place them in a reaction vessel. Add 0.5g nitric acid (25wt%) to the reaction vessel and react at 20℃ and 1MPa absolute pressure for 2h to obtain a water-containing peroxybutyric acid product. Then place the water-containing peroxybutyric acid product in a reactive distillation column. Set the bottom temperature of the reactive distillation column to 35℃, the top temperature to 85℃, and the absolute pressure to 0.015MPa. During the reaction, the reaction is held for 3h. Acetonitrile and water form an azeotrope and enter the top condenser. The condensed material is in the form of an oil-water two-phase mixture. Acetonitrile is completely refluxed as the oil phase and the water phase is completely extracted. The anhydrous peroxy acid product is extracted from the bottom of the column to obtain a peroxybutyric acid synthesis solution.

[0130] (2) The peroxybutyric acid synthesis solution obtained in step (1) was placed in a batch reactor, and pyridine (stabilizer) was added at a stirring speed of 200 rpm to make the molar ratio of pyridine to nitric acid 6:1. After the addition of pyridine was completed, the mixture of peroxybutyric acid synthesis solution and pyridine was reacted at 25°C and an absolute pressure of 0.1 MPa for 1 h to obtain a peroxybutyric acid solution. The conversion rate of hydrogen peroxide was calculated to be 98.5%, the selectivity of the peroxybutyric acid solution was 72%, and the concentration of peroxybutyric acid in the peroxybutyric acid solution was 24.3%.

[0131] Application Example 10

[0132] 50g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxybutyric acid solution obtained in Example 10 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and an absolute pressure of 0.1 MPa for 2 hours to obtain a caprolactone solution. The conversion rate of cyclohexanone was calculated to be 96%, and the selectivity of caprolactone was 95%.

[0133] Comparative Example 1

[0134] The procedure was carried out as described in Example 1, except that only step (1) was performed, and step (2) was omitted, to obtain a perpropionic acid solution. The calculated conversion rate of hydrogen peroxide was 97.5%, the selectivity of the perpropionic acid solution was 82%, and the concentration of perpropionic acid in the perpropionic acid solution was 27.7%.

[0135] Application Comparative Example 1

[0136] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxypropionic acid solution obtained in Comparative Example 1 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 h, and the reaction was then maintained at 45°C and 0.1 MPa for 2 h to obtain a caprolactone solution. The conversion rate of cyclohexanone was 73%, and the selectivity of caprolactone was 27.5%.

[0137] Comparative Example 2

[0138] The procedure was carried out as described in Example 1, except that in step (2), the pyridine was replaced with ammonium chloride to obtain a perpropionic acid solution. The conversion rate of hydrogen peroxide was calculated to be 99.2%, the selectivity of the perpropionic acid solution was 91%, and the concentration of perpropionic acid in the perpropionic acid solution was 30.7%.

[0139] Application Comparative Example 2

[0140] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxypropionic acid solution obtained in Comparative Example 2 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and 0.1 MPa for 1 hour to obtain a caprolactone solution. The conversion rate of cyclohexanone was 85%, and the selectivity of caprolactone was 17.2%.

[0141] Comparative Example 3

[0142] The procedure was carried out as described in Example 1, except that in step (2), the pyridine was replaced with ethanol to obtain a perpropionic acid solution. The calculated conversion rate of hydrogen peroxide was 99.3%, the selectivity of the perpropionic acid was 92%, and the concentration of perpropionic acid in the perpropionic acid solution was 31.1%.

[0143] Application Comparative Example 3

[0144] 98g of cyclohexanone was weighed and placed in a batch reactor, and the temperature was raised to 50°C. A magnetic stirrer was started at 200 rpm, and the peroxypropionic acid solution obtained in Comparative Example 3 was slowly added dropwise to the cyclohexanone. The addition was completed after 0.5 hours, and the reaction was then maintained at 55°C and 0.1 MPa for 1 hour to obtain a caprolactone solution. The conversion rate of cyclohexanone was 89.2%, and the selectivity of caprolactone was 15%.

[0145] Table 1

[0146]

[0147] As can be seen from Table 1, the preparation of peroxy acid products using the composition and method described in this invention can improve the conversion rate of hydrogen peroxide during the reaction process, resulting in a hydrogen peroxide conversion rate >95% and a selectivity of >70% for the prepared peroxy acid products. Furthermore, when the peroxy acid products are used to prepare caprolactone, the conversion rate of cyclohexanone is >95% and the selectivity of the prepared caprolactone is >95%.

[0148] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing peroxyacid, characterized in that, The method includes the following steps: (1) Mix organic solvent, organic acid, hydrogen peroxide and acidic catalyst to obtain peroxy acid synthesis solution; (2) The peroxy acid synthesis solution is reacted with a stabilizer; The stabilizer is a nitrogen-containing basic compound, and the N atom has a lone pair of electrons; the acidic catalyst is selected from one or more of sulfuric acid, nitric acid, heteropolyacids and isopolyacids; the molar ratio of the stabilizer to the acidic catalyst is 1~30:

1.

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, dimethylpyridine, pyrrole, indole, acridine, carbazole and quinoline.

3. The method according to claim 1 or 2, characterized in that, The heteropolyacid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, and silicotungstic acid.

4. The method according to claim 1 or 2, characterized in that, The isopolyacid is selected from one or more of decatungstic acid, heptatungstic acid, octamolybdic acid, and dodecamolybdic acid.

5. The method according to claim 1, characterized in that, Based on the total weight of the organic solvent, organic acid, hydrogen peroxide, and acidic 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 acidic catalyst is 0.01-15% by weight.

6. The method according to claim 5, characterized in that, Based on the total weight of the organic solvent, organic acid, hydrogen peroxide, and acidic catalyst as 100% by weight, the content of the organic solvent is 10-50% by weight, the content of the organic acid is 10-50% by weight, the content of the hydrogen peroxide is 10-60% by weight, and the content of the acidic catalyst is 0.05-10% by weight.

7. The method according to claim 1, characterized in that, 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-hexane, dioxane, dichlorohexane, cyclohexane, benzene, and acetonitrile.

8. The method according to claim 1, characterized in that, The organic acid is selected from one or more of formic acid, acetic acid, propionic acid and butyric acid.

9. The method according to claim 5 or 7, characterized in that, In step (1), the mixing conditions include: temperature of 0~130℃, time of 0.05~30h, and absolute pressure of 0.001~1MPa.

10. The method according to claim 1, characterized in that, The concentration of peroxy acid in the peroxy acid synthesis solution is 5-50% by weight.

11. The method according to claim 1, characterized in that, In step (2), the reaction conditions include: temperature of 10~50℃, time of 0.2~1.5h, and absolute pressure of 0.1~0.3MPa.

12. The method according to claim 1, characterized in that, The concentration of the hydrogen peroxide is 10-80% by weight.

13. The method according to claim 12, characterized in that, The concentration of the hydrogen peroxide is 25-50% by weight.

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