Caprolactam compound liquid and application thereof, and method for transporting and storing caprolactam
The use of caprolactam compound solution has solved the problems of high cost and high energy consumption in long-distance transportation of caprolactam, maintained liquid stability, reduced transportation costs and ensured the quality of downstream polymerization.
Patent Information
- Application Number
- CN202510862371.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-11-07
AI Technical Summary
Existing technologies for transporting caprolactam involve high costs and high energy consumption, especially during long-distance transport where it is difficult to maintain the stability of the liquid structure, which affects the quality of downstream polymerization.
The solution uses caprolactam compound, containing caprolactam and component A (such as acetone, butanone, cyclohexanone, etc.). By controlling the freezing point between -30℃ and 35℃, and transporting and storing it at 5-30℃ and 20-60% relative humidity, the liquid stability is ensured.
This technology enables caprolactam to maintain a stable liquid structure at low temperatures for extended periods, reducing transportation costs without affecting the quality of downstream polymerization.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of transportation and storage of chemical products, in particular to a caprolactam compound liquid and application, and a method for transporting and storing caprolactam. BACKGROUND
[0002] Caprolactam is an important chemical raw material, and its main use is to produce synthetic resins such as nylon 6 and nylon 66 through polymerization. At present, the manufacturers of caprolactam and downstream polymerization customers are scattered in different places. Due to the limitation of transportation cost and distance, the industry is under pressure.
[0003] The melting point of caprolactam is 68-71℃, and it is solid at room temperature. There are two ways to transport caprolactam at present: (1) transporting in liquid form, which requires using high-temperature (above 80℃) tank trucks for heat preservation transportation, and the tank truck is dedicated to a specific purpose. It is also necessary to ensure the sealing and cleanliness of the container to prevent leakage and contamination of the goods. This transportation method has great limitations, especially for northern areas in winter. The heat preservation time of the constant temperature tank truck is limited (about 10 hours), which has great challenges and limitations for long-distance transportation, and the cost of constant temperature tank truck transportation is high. (2) Transporting in solid form, which requires bagging after flaking of caprolactam. This transportation method not only increases the flaking process cost, but also requires melting before polymerization when caprolactam is transported to downstream polymerization plants, further increasing energy consumption. Improving the current transportation method of caprolactam, expanding the radiation radius of caprolactam transportation, and reducing the transportation cost of caprolactam are conducive to the development of new business trade of caprolactam industry.
[0004] To achieve low-cost long-distance transportation of liquid caprolactam, the following problems need to be solved: (1) Caprolactam needs to maintain a stable liquid structure under low-temperature conditions and not be oxidized by air or other media; (2) Caprolactam needs to maintain a stable structure during at least one month of transportation without affecting the quality of downstream polymerization.
[0005] Therefore, it is of great industry challenge and breakthrough significance to effectively solve the problem of low-cost long-distance transportation of liquid caprolactam while maintaining the stability of caprolactam itself. SUMMARY
[0006] The purpose of the present application is to solve the problem of low-cost long-distance transportation of liquid caprolactam.
[0007] In order to achieve the above purpose, the first aspect of the present application provides a caprolactam compound liquid, which contains caprolactam, component A; The component A is selected from acetone, butanone, cyclohexanone, ethyl acetate, butyl acetate, C 6-8 straight-chain alkanes, C1-5 at least one of a linear alkane of C 2-3 at least one of a linear alkane of C The content of the caprolactam is 50-95wt% and the content of the component A is 5-50wt% based on the total mass of the caprolactam compound solution. The freezing point of the caprolactam compound solution is -30-35℃ and the saturated water content is less than 0.1wt%.
[0008] The second aspect of the present application provides a method for preparing the caprolactam compound solution of the first aspect, which comprises mixing caprolactam and component A to obtain the caprolactam compound solution.
[0009] The third aspect of the present application provides the use of the caprolactam compound solution of the first aspect in transporting and / or storing caprolactam.
[0010] The fourth aspect of the present application provides a method for transporting and storing caprolactam, which comprises storing the caprolactam compound solution of the first aspect under sealed conditions at a temperature of 5-30℃ and a relative humidity of 20-60%.
[0011] The caprolactam compound solution provided by the present application has a freezing point in the range of -30-35℃, stable performance, no chemical reaction between the components in the compound solution, and stable structure during storage or transportation for more than 90 days. DETAILED DESCRIPTION
[0012] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges and values should be interpreted as being approximate. The endpoints of the ranges and values are provided as exemplifications of the ranges and values. Other values within the ranges and values are neither practical nor are they to be excluded from the ranges or values. Various embodiments can have different slopes and / or different endpoints.
[0013] As described above, the first aspect of the present application provides a caprolactam compound solution containing caprolactam and component A; The component A is selected from acetone, butanone, cyclohexanone, ethyl acetate, butyl acetate, at least one of a linear alkane of C 6-8 at least one of a linear alkane of C 1-5 at least one of a linear alkane of C 2-3 at least one of a linear alkane of C The content of the caprolactam is 50-95wt% and the content of the component A is 5-50wt% based on the total mass of the caprolactam compound solution. The freezing point of the caprolactam compound solution is -30-35℃ and the saturated water content is less than 0.1wt%.
[0014] The content of the caprolactam in the application can be 50wt%, 53wt%, 55wt%, 57wt%, 60wt%, 63wt%, 65wt%, 67wt%, 70wt%, 73wt%, 75wt%, 77wt%, 80wt%, 83wt%, 85wt%, 87wt%, 90wt%, 93wt%, 95wt%.
[0015] The content of the component A in the application can be 5wt%, 7wt%, 10wt%, 13wt%, 15wt%, 17wt%, 20wt%, 23wt%, 25wt%, 27wt%, 30wt%, 33wt%, 35wt%, 37wt%, 40wt%, 43wt%, 45wt%, 47wt%, 50wt%.
[0016] Preferably, the content of the caprolactam is 70-85wt% and the content of the component A is 15-30wt% based on the total mass of the caprolactam complex solution. The inventors have found that in this preferred case, the freezing point of the obtained caprolactam complex solution is lower, which is more convenient for storage and transportation.
[0017] Preferably, the component A is selected from at least one of acetone, butanone, cyclohexanone, ethyl acetate, butyl acetate, n-hexane, n-octane, methanol, ethanol, propanol, ethylene glycol.
[0018] More preferably, the component A is selected from at least one of acetone, ethyl acetate, n-hexane, n-octane, methanol, ethanol, propanol, ethylene glycol.
[0019] Particularly preferably, the component A is a combination of methanol and ethylene glycol, and the content mass ratio of the methanol to the ethylene glycol is 5-1:1. The inventors have found that in this preferred case, the obtained caprolactam complex solution has more excellent low-temperature storage performance.
[0020] Preferably, the freezing point of the caprolactam complex solution is -30℃ to 5℃.
[0021] As described above, the second aspect of the application provides a method for preparing the caprolactam complex solution of the first aspect, which comprises: mixing caprolactam and component A; obtaining the caprolactam complex solution.
[0022] It should be noted that the definitions and dosages of the caprolactam and the component A in the application are the same as those of the corresponding components in the first aspect, which will not be described here again, and those skilled in the art should not understand it as a limitation of the application.
[0023] In this invention, the method for preparing the caprolactam compound solution is preferably carried out under stirring. There are no particular requirements for the stirring speed and time, as long as the caprolactam and component A are mixed evenly. Those skilled in the art can use parameters known in the art. For example, caprolactam and component A are mixed at 15-30°C and 60-300 rpm for 20-40 minutes.
[0024] As previously stated, a third aspect of the present invention provides the use of the caprolactam compound solution described in the first aspect in the transportation and / or storage of caprolactam.
[0025] As previously stated, a fourth aspect of the present invention provides a method for transporting and storing caprolactam, the method comprising: storing the caprolactam compound solution described in the first aspect under sealed conditions at a temperature of 5-30°C and a relative humidity of 20-60%.
[0026] According to a preferred embodiment, the method further includes: distilling the stored caprolactam compound solution to obtain caprolactam and component A.
[0027] In a preferred embodiment, the distillation conditions include: a temperature of 50-120°C, a time of 1-6 hours, and a reflux ratio of 1-9:1. The inventors have found that under these preferred conditions, caprolactam can be separated from component A more completely, resulting in higher purity caprolactam. Both the separated caprolactam and hydrocarbon component A meet national performance standards and can continue to be used normally.
[0028] The present invention will be described in detail below through examples. Unless otherwise specified, the experimental methods and detection methods involved in the following examples are all conventional experimental methods and detection methods already existing in the prior art. All reagents involved in the following examples are commercially available analytical grade. Room temperature in the following examples refers to 20±2℃.
[0029] The saturated water content of the caprolactam compound solution was determined by the Karl Fischer coulometric method, using a Metrohm 756KF coulometric moisture analyzer.
[0030] Example 1 80 kg of caprolactam and 20 kg of n-hexane were mixed and stirred at room temperature and 150 rpm for 30 min until a clear and transparent solution was obtained, thus obtaining the caprolactam / n-hexane compound solution.
[0031] Take 50 mL of sample and test the freezing point using DSC (differential scanning calorimetry).
[0032] The caprolactam / n-hexane compound liquid was sealed and placed in a constant temperature and humidity test box (relative humidity 50%) at 5℃ for 90 days; then the caprolactam compound liquid stored for 90 days was separated by a rectifying column, and after the rectification was completed, the components A collected at the top of the column and the caprolactam at the bottom of the column were respectively subjected to index detection, the performance of the caprolactam after rectification was tested according to the standard GB / T 13254-2017, and the test results are shown in Tables 1 and 2.
[0033] The remaining examples and comparative examples were carried out by the method similar to that of Example 1, except that the formula of the compound liquid and the rectification conditions were different, and the specific conditions are shown in Table 1.
[0034] Table 1 (1 kg is represented by each weight part)
[0035] Table 1 (continued)
[0036] Table 1 (continued)
[0037] Table 2 Quality indexes of caprolactam after separation of caprolactam compound liquid by rectification equipment
[0038] Table 2 (continued)
[0039] Table 2 (continued)
[0040] From the above results, it can be seen that the caprolactam compound liquid provided by the present application can maintain a stable liquid structure for a long time at a lower temperature.
[0041] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.
Claims
1. A caprolactam complex solution, characterized by, The caprolactam compound liquid contains caprolactam and component A; The component A is selected from at least one of acetone, butanone, cyclohexanone, ethyl acetate, butyl acetate, C 6-8 linear alkanes, C 1-5 monohydric alcohols, C 2-3 dihydric alcohols. The content of the caprolactam is 50-95 wt% and the content of the component A is 5-50 wt% based on the total mass of the caprolactam compound liquid. The freezing point of the caprolactam compound liquid is -30℃ to 35℃ and the saturated water content is less than 0.1 wt%.
2. The caprolactam complexing solution according to claim 1, characterized in that, The content of the caprolactam is 70-85 wt% and the content of the component A is 15-30 wt% based on the total mass of the caprolactam compound liquid.
3. The caprolactam complexing solution according to claim 1 or 2, characterized in that, The component A is at least one of acetone, butanone, cyclohexanone, ethyl acetate, butyl acetate, n-hexane, n-octane, methanol, ethanol, propanol, and ethylene glycol.
4. The caprolactam complex solution according to claim 1 or 2, characterized by The component A is a combination of methanol and ethylene glycol, and the mass ratio of the content of the methanol to the ethylene glycol is 5-1:
1.
5. The caprolactam complexing solution according to any one of claims 1 to 4, characterized in that, The freezing point of the caprolactam compound liquid is -30℃ to 5℃.
6. A process for the preparation of the caprolactam complex solution according to any one of claims 1 to 5, characterized in that The method comprises mixing caprolactam and component A to obtain the caprolactam compound liquid.
7. Use of the caprolactam compound liquid according to any one of claims 1-5 in transporting and / or storing caprolactam.
8. A method of transporting and storing caprolactam, characterized in that, The method comprises storing the caprolactam compound liquid according to any one of claims 1-5 under sealed conditions at a temperature of 5-30℃ and a relative humidity of 20-60%.
9. The method of claim 8, wherein, The method further comprises rectifying the stored caprolactam compound liquid to obtain caprolactam and component A.
10. The method according to claim 8 or 9, characterized in that, The rectification conditions comprise a temperature of 50-120℃, a time of 1-6h, and a reflux ratio of 1-9:1.