Preparation method of anhydrous solid peroxy acid for epsilon-caprolactone production

Abstract

The invention provides a preparation method of anhydrous solid peroxy acid for epsilon-caprolactone production, which comprises the following steps: (1) taking C4H4O3 and a solvent in a three-necked flask, fully dissolving C4H4O3 under mechanical stirring, slowly dropwise adding H2O2, fully reacting in a water bath, carrying out suction filtration after the reaction is finished to obtain a white granular solid, washing with the solvent, and drying to obtain the anhydrous solid peroxy acid for epsilon-caprolactone production; the solid peroxysuccinic acid is obtained. (2) dissolving a peroxysuccinic acid solid and CH3COOH, after the dissolution is completed, filtering the reaction liquid to separate the solid from the liquid, leaving the solid for later use, taking the liquid, adding a drying agent into the liquid, fully stirring in a water bath, after the drying is completed, filtering, and mixing and dissolving the liquid and the solid for later use to obtain a dried peroxysuccinic acid-CH3COOH mixed solution; according to the invention, the drying process of the drying agent on the peroxysuccinic acid is realized, and the possible industrial safety problem of a vacuum drying mode is avoided.

Description

Technical Field

[0001] The invention relates to the field of peracid preparation, and in particular to a method for preparing anhydrous solid peracid for producing epsilon-caprolactone. Background Art

[0002] ε-caprolactone is a widely used chemical intermediate. It can bring excellent chemical properties to the synthetic product through the synthesis reaction and has a wide range of applications in the field of materials. BV oxidation is the main way to produce ε-caprolactone in industry today. ε-caprolactone is obtained by oxidizing cyclohexanone. Peroxyacid is the best oxidant, mainly including peroxy CH 3 COOH, peroxybenzoic acid, peroxysuccinic acid, etc.

[0003] During the cyclohexanone oxidation reaction, the water in the system has a great impact on ε-caprolactone. High water content will lead to the hydrolysis of ε-caprolactone. Therefore, in the ε-caprolactone synthesis process, the water removal process of peroxyacid is very important. Common drying methods can remove the moisture in peroxyacid to a great extent, but they are accompanied by safety issues in industry. The accumulation heat of peroxyacid can lead to the risk of explosion. Developing a process for drying peroxyacid with a desiccant is safer and easier to operate than the vacuum drying process. Summary of the invention

[0004] The technical problem to be solved by the present invention is: using a desiccant to dry peroxysuccinic acid to solve the safety problems of high accumulation heat and easy explosion in traditional vacuum drying.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] (1) Take C 4 H 4 O 3 and solvent in a three-necked flask and stir mechanically to make C 4 H 4 O 3 Dissolve thoroughly, then slowly drip H 2 O 2 , react fully in a water bath, filter after the reaction to obtain a white granular solid, wash with a solvent to obtain solid peroxysuccinic acid.

[0007] (2) Take the peroxysuccinic acid solid and CH 3 COOH is dissolved, and after the dissolution is complete, the reaction liquid is filtered to separate the solid and the liquid, and the solid is reserved for use. The liquid is taken and a desiccant is added thereto, and the mixture is stirred fully in a water bath. After the drying is complete, the liquid is filtered and mixed with the reserved solid to obtain dry peroxysuccinic acid -CH 3 COOH mixed solution.

[0008] In the above method, the solvent is a halogenated alkane, which can dissolve succinic anhydride smoothly and ensure the rapid progress of the oxidation reaction.

[0009] In the above method, the solvent is CH 2 Cl 2 , C 2 H 4 Cl 2 or CCl 4 .

[0010] In the above method, the solvent is an aromatic hydrocarbon, which can dissolve succinic anhydride smoothly and ensure the rapid progress of the oxidation reaction.

[0011] In the above method, the solvent aromatic hydrocarbon is C 7 H 8 , C 6 H 4 Cl 2 or C 6 H 6 .

[0012] In the above method, the desiccant is a metal salt or anhydride, which can effectively remove moisture from the solution.

[0013] In the above method, the metal salt or acid anhydride is Na 2 SO 4 MgSO 4 , C 4 H 4 O or C 4 H 6 O 3 .

[0014] In the above method, the following drying process can be used:

[0015] Take the peracid solution into a three-necked flask, add 5-20g of desiccant, stir mechanically in a water bath at 25-40℃ for 0.5-2h, and filter to obtain an anhydrous peracid solution.

[0016] In the above step (2), the liquid and the reserved solid can be mixed in a mass ratio of 5:2 to obtain dry peroxysuccinic acid-CH 3 COOH mixed solution.

[0017] The method provided by the invention can synthesize solid peroxysuccinic acid for use in the preparation of epsilon-caprolactone.

[0018] Compared with the prior art, the present invention has the following main advantages:

[0019] (1) High safety and easy operation:

[0020] In the past, peroxysuccinic acid was mainly dried by vacuum drying, which has the advantage of greatly reducing the drying temperature and removing the moisture in the peroxysuccinic acid more fully. However, the vacuum drying process directly dries the peroxysuccinic acid, which is easy to decompose, so this operation process is accompanied by the risk of explosion, and this process is difficult to operate in industrial production.

[0021] The process of drying peroxysuccinic acid by using a desiccant has the advantage that the peroxysuccinic acid flows in liquid throughout the process and there is no high-temperature treatment process. Compared with the vacuum drying process, it is safer and easier to operate.

[0022] (2) The present invention realizes the drying process of peroxysuccinic acid by a desiccant, avoids the possible safety problems of the vacuum drying method in industry, and is easy to operate.

[0023] This process uses peroxysuccinic acid as the solute and acetic acid as the solvent, mixes to obtain a peroxyacid solution, adds a metal salt or anhydride as a desiccant, removes moisture from the solution, and obtains a dry peroxysuccinic acid-acetic acid mixed solution after filtration, which can be directly used for the synthesis of ε-caprolactone at low temperature and without vacuum requirements. DETAILED DESCRIPTION

[0024] At present, the indirect oxidation method generally adopts a two-step method, first using a certain concentration of hydrogen peroxide to oxidize the indirect oxidant, and then using the generated peracid to oxidize cyclohexanone to produce ε-caprolactone. Since ε-caprolactone is easily hydrolyzed to form caproic acid, it seriously affects the quality of the product. Although the solid peracid method can remove most of the water in the first step of preparing caprolactone, there is still a part of free water and bound water in the product. Since solid peracid is easy to decompose and release a lot of heat, how to safely and efficiently remove the small amount of free water and bound water in it is a key technical problem that restricts this process.

[0025] The present invention adopts the solvent of the second step of the caprolactone synthesis process to dissolve the water-containing solid peroxy acid, and then removes a small amount of water in the peroxy acid through a desiccant adsorption process. The advantage of this process is that the peroxysuccinic acid flows in the liquid throughout the process, and there is no high-temperature treatment process. Compared with the traditional vacuum drying process, it is safer and easier to operate, and has lower energy consumption.

[0026] The method provided by the present invention is further described below in conjunction with specific embodiments, which is only to illustrate the technical concept and features of the present invention, but does not constitute any limitation to the present invention.

[0027] Example 1

[0028] Take 25gC 4 H 4 O 3 and 160mlCH 2Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 15 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred at 35°C (speed of 300 rpm) for 2 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.76%, the caprolactone yield could reach 77.67%, and the selectivity could reach 77.86%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.82%, the caprolactone yield was 78.12%, and the selectivity was 78.26%.

[0029] This embodiment adopts the following desiccant drying process:

[0030] Take the peroxyacid solution in a three-necked flask and add 15g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 2 h, and filtered to obtain an anhydrous peracid solution.

[0031] The machine may be a paddle stirrer or a spiral stirrer, the same as in the following embodiments.

[0032] Example 2

[0033] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 20 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 35°C for 1.5 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.99%, the caprolactone yield could reach 74.34%, and the selectivity could reach 74.35%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.91%, the caprolactone yield was 76.14%, and the selectivity was 76.21%.

[0034] This embodiment adopts the following desiccant drying process:

[0035] Take the peroxyacid solution in a three-necked flask and add 20g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 1.5 h, and filtered to obtain an anhydrous peracid solution.

[0036] Example 3

[0037] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 15 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred at 40°C (speed of 300 rpm) for 2 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.98%, the caprolactone yield could reach 81.44%, and the selectivity could reach 81.46%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.96%, the caprolactone yield was 84.56%, and the selectivity was 84.59%.

[0038] This embodiment adopts the following desiccant drying process:

[0039] Take the peroxyacid solution in a three-necked flask and add 15g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 40°C for 2 h, and filtered to obtain an anhydrous peracid solution.

[0040] Example 4

[0041] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 15 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 25°C for 2 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.97%, the caprolactone yield could reach 71.5%, and the selectivity could reach 71.52%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.97%, the caprolactone yield was 73.12%, and the selectivity was 73.14%.

[0042] This embodiment adopts the following desiccant drying process:

[0043] Take the peroxyacid solution in a three-necked flask and add 15g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 25°C for 2 h, and filtered to obtain an anhydrous peracid solution.

[0044] Example 5

[0045] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1.5 h. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 20 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 35°C for 1.5 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.99%, the caprolactone yield could reach 74.44%, and the selectivity could reach 74.45%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.99%, the caprolactone yield was 75.34%, and the selectivity was 75.35%.

[0046] This embodiment adopts the following desiccant drying process:

[0047] Take the peroxyacid solution in a three-necked flask and add 20g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 1.5 h, and filtered to obtain an anhydrous peracid solution.

[0048] Example 6

[0049] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1.25 h. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 20 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 35°C for 1.5 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.98%, the caprolactone yield could reach 74.13%, and the selectivity could reach 74.14%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.84%, the caprolactone yield was 76.15%, and the selectivity was 76.27%.

[0050] This embodiment adopts the following desiccant drying process:

[0051] Take the peroxyacid solution in a three-necked flask and add 20g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 1.5 h, and filtered to obtain an anhydrous peracid solution.

[0052] Example 7

[0053] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 5 g Na 2 SO 4 The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 35°C for 1.5 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.98%, the caprolactone yield could reach 62.23%, and the selectivity could reach 62.64%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.99%, the caprolactone yield was 65.35%, and the selectivity was 65.36%.

[0054] This embodiment adopts the following desiccant drying process:

[0055] Take the peroxyacid solution in a three-necked flask and add 5g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 1.5 h, and filtered to obtain an anhydrous peracid solution.

[0056] Example 8

[0057] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 10 g Na2 SO 4 The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 35°C for 1.5 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.97%, the caprolactone yield could reach 72.23%, and the selectivity could reach 73.25%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.98%, the caprolactone yield was 73.13%, and the selectivity was 73.14%.

[0058] This embodiment adopts the following desiccant drying process:

[0059] Take the peroxyacid solution in a three-necked flask and add 10g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 1.5 h, and filtered to obtain an anhydrous peracid solution.

[0060] Example 9

[0061] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 15 g Na 2 SO 4The solid was used as a desiccant and mechanically stirred at 35°C (speed of 300 rpm) for 2 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.76%, the caprolactone yield could reach 77.67%, and the selectivity could reach 77.86%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.81%, the caprolactone yield was 78.34%, and the selectivity was 78.49%.

[0062] This embodiment adopts the following desiccant drying process:

[0063] Take the peroxyacid solution in a three-necked flask and add 15g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 2 h, and filtered to obtain an anhydrous peracid solution.

[0064] Example 10

[0065] Take 25gC 4 H 4 O 3 and 160mlCH 2 Cl 2 In a three-necked flask, C 4 H 4 O 3 Dissolve thoroughly, then slowly drop 17g of 50% H 2 O 2 , reacted fully at 35 °C, and after the reaction was completed, a white granular solid was obtained by filtration with a vacuum pump. 2 Cl 2 Wash and dry at 60℃ under vacuum to obtain solid peroxysuccinic acid. Take 46.832g of the non-vacuum dried peroxysuccinic acid solid and mix with 110ml CH 3 COOH was dissolved at 35°C for 1 hour. After the dissolution was complete, the solid and liquid were separated by filtration. The solid was reserved for later use. 15 g Na 2 SO 4The solid was used as a desiccant and mechanically stirred (speed: 300 rpm) at 35°C for 0.5 h. After drying, the mixture was filtered and the liquid was mixed with the reserved solid to obtain peroxysuccinic acid -CH 3 COOH mixed solution. Take 9.814g cyclohexanone and 3 drops of C 6 H 7 N in a three-necked flask, slowly add peroxysuccinic acid -CH 3 The COOH mixed solution was mechanically stirred (speed was 300 ml / min) while maintaining the reaction temperature at 55°C. The addition was completed within 30 minutes and the reaction was continued for 3 hours. After the reaction was completed, the cyclohexanone conversion rate could reach 99.99%, the caprolactone yield could reach 69.45%, and the selectivity could reach 69.46%. Under the same conditions, the vacuum drying process was sampled and analyzed, and the cyclohexanone conversion rate was 99.99%, the caprolactone yield was 71.12%, and the selectivity was 71.13%.

[0066] This embodiment adopts the following desiccant drying process:

[0067] Take the peroxyacid solution in a three-necked flask and add 15g Na 2 SO 4 The solid was mechanically stirred (at a speed of 300 rpm) in a water bath at 35°C for 0.5 h, and filtered to obtain an anhydrous peracid solution.

Claims

1. A method for preparing anhydrous solid peroxyacid for the production of ε-caprolactone, characterized in that: A method comprising the following steps is employed: (1) C4H4O3 and a solvent are placed in a three-necked flask, and the C4H4O3 is fully dissolved under mechanical stirring, and then H2O2 is slowly added dropwise to react fully under a water bath. After the reaction is completed, a white granular solid is obtained by suction filtration, and the solid peroxysuccinic acid is obtained by washing with a solvent; (2) Dissolve the peroxysuccinic acid solid in CH3COOH. After the dissolution is complete, filter the reaction solution to separate the solid and the liquid, keep the solid for later use, take the liquid and add a desiccant thereto, stir well in a water bath, filter the liquid and mix it with the solid for later use, and obtain a dry peroxysuccinic acid-CH3COOH mixed solution after drying.

2. The method according to claim 1, characterized in that The solvent is a halogenated alkane.

3. The method according to claim 2, characterized in that The solvent is CH2Cl2, C2H4Cl2 or CCl4.

4. The method according to claim 1, characterized in that: The solvent is an aromatic hydrocarbon.

5. The method according to claim 4, characterized in that The solvent aromatic hydrocarbon is C7H8, C6H4Cl2 or C6H6.

6. The method according to claim 1, characterized in that The desiccant is a metal salt or an acid anhydride.

7. The method according to claim 6, characterized in that The metal salt or acid anhydride is Na2SO4, MgSO4, C4H4O or C4H6O3.

8. The method according to claim 1, characterized in that The following drying process is used: Take the peracid solution into a three-necked flask, add 5-20g of desiccant, stir mechanically in a water bath at 25-40℃ for 0.5-2h, and filter to obtain an anhydrous peracid solution.

9. The method according to claim 1, characterized in that: In step (2), the liquid and the reserved solid are mixed in a mass ratio of 5:2 to obtain a dry peroxysuccinic acid-CH3COOH mixed solution.

10. The method according to any one of claims 1 to 9, characterized in that Application of peroxysuccinic acid-CH3COOH mixed solution in the preparation of ε-caprolactone.