Preparation method of ultra-pure decamethylene diamine
Through the inert gas bubbling suspension and layered melt crystallization process, the problems of low purity and yield of decanediamine in the traditional process are solved, and the preparation of high-purity decanediamine is achieved, which has environmental and economic advantages.
Patent Information
- Application Number
- CN202510789728.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-09-16
AI Technical Summary
It is difficult to prepare high-purity decanediamine using existing technologies. Traditional processes have low yields, limited purity, high energy consumption, and environmental pollution problems.
The suspension and layer melt crystallization methods with inert gas bubbling are combined with the suspension melt crystallization and layer melt crystallization processes, and the inert gas is used as a protective gas and nucleation site to achieve efficient purification of decanediamine.
The purity of decanediamine reached 99.99%, meeting the performance requirements of downstream materials, improving the yield and reducing costs. At the same time, no three wastes were generated, meeting the requirements of green chemical industry.
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Figure CN120647541A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of preparation of amine compounds, and particularly relates to a method for preparing ultra-high-purity decanediamine. Background Art
[0002] Decanediamine (1,10-diaminodecane) is an organic compound, also known as dodecylamine, with the chemical formula C 10 H 24 N2 is a white or pale yellow crystal with a melting point of 62-63°C and a boiling point of 139-140°C (1.6kPa). It is soluble in ethanol and rapidly forms salts when reacting with carbon dioxide in air. Decanediamine, as a raw material for organic synthesis, is commonly used in polymer polymerization and pharmaceutical refining. It is a key monomer for the synthesis of high-performance polyamides (nylons), epoxy resin curing agents, surfactants, and biomedical materials. It is also an indispensable raw material for high-end engineering plastics (such as gears and bearings), fibers, and specialty films. For example, typical nylon 1010 is formed by the condensation of decanediamine and sebacic acid, which gives it excellent wear resistance, oil resistance, and low-temperature toughness.
[0003] The industrial production system for decanediamine has been developed for over 60 years. Its mainstream technology has long relied on a traditional synthesis route: sebaconitrile as the starting material, Raney nickel as the catalyst, and batch catalytic hydrogenation as the core process. While this route boasts high process maturity and ease of operation, it suffers from significant technical shortcomings, including product yields below 95% (mass fraction) and crude product purities below 97.5%, making it difficult to achieve breakthroughs in key performance indicators.
[0004] Although patent CN117776928A, "A Method for Preparing Decanediamine," uses Cr-modified Raney nickel as a catalyst to catalytically hydrogenate decanedionitrile and ethanol to produce a decanedioniamine product with a purity of 98.0-99.8%, the increasing demands for material performance in downstream applications for decanedioniamine have led to a decanedioniamine monomer purity exceeding 99.9%, a key factor affecting the molecular weight, mechanical properties, and thermal stability of the polymer. Conventional distillation purification requires high temperatures, which can easily cause thermal decomposition (such as deamination or oxidation) of decanedioniamine, disrupting its molecular structure. Furthermore, some impurities form azeotropes with decanedioniamine, making efficient separation difficult with conventional distillation. This results in a limited upper limit on purity (<99.9%). Furthermore, intermittent processes are energy-intensive and require complex wastewater and exhaust gas treatment, making them unsuitable for green chemical processing. Summary of the Invention
[0005] In view of the above problems, the present invention provides a green, environmentally friendly and low-cost method for preparing ultra-high-purity decanediamine (purity ≥99.99%).
[0006] The technical solutions of the present invention are as follows:
[0007] A method for preparing ultra-high-purity decanediamine, characterized by comprising the following steps:
[0008] 1) completely melting the crude decanediamine at 65-70° C. under an inert gas atmosphere, and then performing suspension melt crystallization with inert gas bubbling. During the crystallization process, when the temperature drops to 40-60° C., the temperature is maintained constant; after the crystallization is completed, the slurry is subjected to solid-liquid separation to obtain a crude decanediamine solid phase material;
[0009] 2) completely melting the solid crude decanediamine obtained in step 1) at 65-70° C., and then performing layered melt crystallization with inert gas bubbling, gradually lowering the temperature to 55-61° C. and then maintaining the temperature constant during the crystallization process, and discharging the mother liquor after crystal growth is complete;
[0010] 3) heating the crystals obtained in step 2) to sweat under an inert gas atmosphere, and discharging the sweating liquid after the sweating is completed; then completely melting the crystals at 65-70° C., and the melted product is a decanediamine product with a purity greater than 99.99%.
[0011] Furthermore, in the step 1), the flow rate of the inert gas introduced during the suspension melt crystallization process with inert gas bubbling is controlled at 0.01 to 2 L / min.
[0012] Furthermore, in the step 2), the flow rate of the inert gas introduced during the layered melt crystallization process with inert gas bubbling is controlled at 0.05 to 2 L / min.
[0013] Furthermore, in the step 1), the mass percentage of the crude decanediamine as the raw material is ≥70%; and the residence time of the suspension melt crystallization is 1 to 8 hours.
[0014] Furthermore, in the step 2), the cooling rate is 0.1 to 10 K / h; after cooling, the constant temperature is maintained for 0.5 to 2 hours.
[0015] Furthermore, in step 3), the heating rate of the crystal during sweating is 0.1-30 K / h, the final temperature of the heating is 58-65° C., and the constant temperature time after heating to the final temperature is 0.5-2 h.
[0016] Furthermore, the step 1) further comprises the following operation: recrystallizing the liquid phase obtained by solid-liquid separation according to the crystallization method of this step until the mass percentage of decanediamine is less than 40%, and discharging the residual liquid.
[0017] Furthermore, the step 2) further comprises the following operation: collecting the mother liquor and performing recrystallization as the crystallization raw material of the step 1); the step 3) further comprises the following operation: collecting the sweat liquid and performing recrystallization as the crystallization raw material of the step 2).
[0018] Furthermore, the step 1) further comprises the following operation: the obtained solid phase crude material of decanediamine is crystallized multiple times according to the crystallization method of this step.
[0019] The beneficial effects of the present invention are as follows:
[0020] 1) One advantage of the present invention is that the material is firstly purified by a suspension melt crystallization method under inert gas bubbling and the purity of the mother liquor is reduced, thereby shortening the nucleation time and improving the overall yield while protecting the material from reaction with CO2 in the air; secondly, the material is purified to a purity of more than 99.99% by a layered melt crystallization method under inert gas bubbling, meeting the purity of the decanediamine monomer (≥99.9%) required for material performance in downstream fields.
[0021] 2) The present invention innovatively utilizes inert gas bubbling coupled melt crystallization to prepare ultra-high-purity decanediamine. On the one hand, the inert gas acts as a protective gas to prevent decanediamine from reacting with CO2 in the air to form salts during crystallization. On the other hand, the bubbles can act as heterogeneous nucleation sites to promote the crystal nucleation process, thereby shortening the induction period and increasing the purity of decanediamine to over 99.99%. At the same time, this solves the industry problem faced by those skilled in the art of increasing the purity of decanediamine polymerization-grade monomers while simultaneously increasing yield and reducing costs.
[0022] 3) The present invention is applicable to crude decanediamine (mass percentage ≥ 70%). After the raw materials enter the separation process, the decanediamine obtained in each step with a mass percentage ≥ 40% can be reused. The decanediamine in the entire system of the present invention can be recovered and repurified, with a total recovery rate of up to 99%.
[0023] 4) The process of the present invention does not require the addition of an external solvent, thereby simplifying the operation and reducing costs. The process of the present invention does not generate any three wastes and is environmentally friendly. In addition, the process of the present invention is also flexible and can be adjusted according to actual production needs. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The figure is a simplified process flow diagram for preparing ultra-high-purity decanediamine according to the present invention. Specific implementation plan
[0025] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0026] Example 1
[0027] 1) 436.85 g of a crude decanediamine product having a mass percentage of 97.68% was added to a suspension melt crystallizer and completely melted at 70° C., while simultaneously introducing an inert gas into the crystallizer; the liquid phase formed after the melt was subjected to suspension melt crystallization at a constant temperature of 58° C. by bubbling an inert gas, the flow rate of the inert gas introduced during the crystallization process being controlled at 1 L / min, and the crystallization residence time being 2 h; after the crystallization was completed, the slurry was subjected to solid-liquid separation to obtain a solid phase crude decanediamine material having a mass fraction of approximately 99.43%.
[0028] The liquid phase obtained by solid-liquid separation is recrystallized according to the crystallization method of this step until the mass percentage of decanediamine is less than 40%, and the residual liquid is discharged.
[0029] 2) The crude solid phase of decanediamine obtained in step 1) was completely melted into a liquid at 70°C and then introduced into a layered melt crystallizer for inert gas bubbling crystallization. The inert gas flow rate during crystallization was controlled at 0.5 L / min. During the crystallization process, the temperature was first cooled at a rate of 5 K / h to a final temperature of 60°C, then maintained at 60°C for 1 hour to allow complete crystal growth, after which the mother liquor was discharged. The mother liquor was returned to step 1) as the crystallization feedstock for recrystallization.
[0030] 3) The crystals obtained in step 2) were further subjected to sweating treatment under an inert gas atmosphere at a heating rate of 10 K / h to 64.5° C., then maintained at this temperature for 0.5 h. After completion of the sweating treatment, the sweating liquid was discharged and used as a crystallization raw material for recrystallization in step 2). The sweated crystals were heated to 70° C. to completely melt, yielding pure decanediamine with a mass purity of 99.995%. The total yield of decanediamine was 95.87%.
[0031] Example 2
[0032] 1) 445.39 g of a crude decanediamine product having a mass percentage of 90.27% was added to a suspension melt crystallizer and completely melted at 70° C., while simultaneously introducing an inert gas into the crystallizer; the liquid phase formed after the melt was subjected to suspension melt crystallization at a constant temperature of 53° C. by bubbling an inert gas, the flow rate of the inert gas introduced during the crystallization process being controlled at 1.5 L / min, and the crystallization residence time being 4 hours; after completion of the crystallization, the slurry was subjected to solid-liquid separation to obtain a solid phase crude decanediamine material having a mass fraction of approximately 98.44%.
[0033] The liquid phase obtained by solid-liquid separation is recrystallized according to the crystallization method of this step until the mass percentage of decanediamine is less than 40%, and the residual liquid is discharged.
[0034] 2) The crude solid phase of decanediamine obtained in step 1) was completely melted into a liquid at 70°C and then introduced into a layered melt crystallizer for inert gas bubbling crystallization. The inert gas flow rate during crystallization was controlled at 1 L / min. During the crystallization process, the temperature was first cooled at a rate of 7 K / h to a final temperature of 56°C, then maintained at 56°C for 1.5 hours to complete crystal growth, after which the mother liquor was discharged. The mother liquor was returned to step 1) as the crystallization feedstock for recrystallization.
[0035] 3) The crystals obtained in step 2) were further subjected to sweating treatment under an inert gas atmosphere at a heating rate of 15 K / h to 64.3° C., then maintained at this temperature for 1 hour. After completion of the sweating treatment, the sweating liquid was discharged and used as a crystallization raw material for recrystallization in step 2). The sweated crystals were heated to 70° C. to completely melt, yielding pure decanediamine with a mass purity of 99.992%. The total yield of decanediamine was 80.71%.
[0036] Example 3
[0037] 1) 452.67 g of a crude decanediamine product having a mass percentage of 79.66% was added to a suspension melt crystallizer and completely melted at 68° C., while simultaneously introducing an inert gas into the crystallizer; the liquid phase formed after the melt was subjected to suspension melt crystallization at a constant temperature of 49° C. by bubbling inert gas, the flow rate of the inert gas introduced during the crystallization process being controlled at 2 L / min, and the crystallization residence time being 4 hours; after completion of the crystallization, the slurry was subjected to solid-liquid separation to obtain a solid phase crude decanediamine material having a mass fraction of approximately 96.64%.
[0038] 2) The solid crude decanediamine obtained by the first-stage suspension melt crystallization in step 1) was completely melted into a liquid at 70° C. and then continuously fed into a second-stage inert gas bubbling suspension melt crystallizer. The inert gas flow rate was controlled at 1 L / min, and the liquid phase was kept at a constant temperature of 60° C. and further inert gas bubbling crystallization was performed for 2 hours. After the crystallization was completed, the slurry was subjected to solid-liquid separation to obtain a solid-phase decanediamine product with a mass fraction of approximately 99.06%.
[0039] The liquid phase obtained by solid-liquid separation in steps 1) and 2) is recrystallized according to the crystallization method in step 1) until the mass percentage of decanediamine is less than 40%, and the residual liquid is discharged.
[0040] 3) The decanediamine product obtained by the secondary suspension melt crystallization in step 2) was completely melted into a liquid at 70°C and then introduced into a layered melt crystallizer for inert gas bubbling crystallization. The inert gas flow rate during the crystallization process was controlled at 1.5 L / min. During the crystallization process, the temperature was first cooled at a rate of 2 K / h to a final temperature of 55°C, then maintained at 55°C for 2 hours to complete crystal growth, after which the mother liquor was discharged. The mother liquor was returned to step 1) as the crystallization feedstock for recrystallization.
[0041] 4) The crystals obtained in step 3) were further subjected to sweating treatment under an inert gas atmosphere at a heating rate of 10 K / h to 63.5° C., then maintained at this temperature for 1.5 hours. After completion of the sweating treatment, the sweating liquid was discharged and used as a raw material for recrystallization in step 3). The sweated crystals were heated to 70° C. to completely melt, yielding pure decanediamine with a mass purity of 99.991%. The total yield of decanediamine was 61.28%.
[0042] Example 4
[0043] 1) 458.96 g of a crude decanediamine product having a mass percentage of 66.43% was added to a suspension melt crystallizer and completely melted at 68° C., while simultaneously introducing an inert gas into the crystallizer; the liquid phase formed after the melt was subjected to suspension melt crystallization at a constant temperature of 45° C. by bubbling an inert gas, the flow rate of the inert gas introduced during the crystallization process being controlled at 2 L / min, and the crystallization residence time being 6 hours; after the crystallization was completed, the slurry was subjected to solid-liquid separation to obtain a solid phase crude decanediamine material having a mass fraction of approximately 83.26%.
[0044] 2) The solid crude decanediamine obtained by the first-stage suspension melt crystallization in step 1) was completely melted into a liquid at 68° C. and then continuously fed into a second-stage inert gas bubbling suspension melt crystallizer. The inert gas flow rate was controlled at 1.5 L / min, and the liquid phase was further subjected to inert gas bubbling crystallization at a constant temperature of 60° C. for a residence time of 2 hours. After the crystallization was completed, the slurry was subjected to solid-liquid separation to obtain a solid-phase decanediamine product with a mass fraction of approximately 97.11%.
[0045] 3) The decanediamine product obtained by the secondary suspension melt crystallization in step 2) was completely melted into a liquid at 70° C. and then continuously fed into a tertiary inert gas bubbling suspension melt crystallizer. The inert gas flow rate was controlled at 1 L / min, and the liquid phase was kept at a constant temperature of 60° C. and further inert gas bubbling crystallization was performed for a residence time of 2 hours. After the crystallization was completed, the slurry was subjected to solid-liquid separation to obtain a solid-phase decanediamine product with a mass fraction of approximately 99.28%.
[0046] The liquid phase obtained by solid-liquid separation from step 1) to step 3) is recrystallized according to the crystallization method of step 1) until the mass percentage of decanediamine is less than 40%, and the residual liquid is discharged.
[0047] 4) The decanediamine product obtained by the three-stage suspension melt crystallization in step 3) was completely melted into a liquid at 70°C and then introduced into a layered melt crystallizer for inert gas bubbling crystallization. The inert gas flow rate during the crystallization process was controlled at 2 L / min. During the crystallization process, the temperature was first cooled at a rate of 2 K / h to a final temperature of 55°C, then maintained at 55°C for 2 hours to complete crystal growth, after which the mother liquor was discharged. The mother liquor was returned to step 1) as the crystallization feedstock for recrystallization.
[0048] 5) The crystals obtained in step 4) were further subjected to sweating treatment under an inert gas atmosphere at a heating rate of 8 K / h to 63.5° C., then maintained at this temperature for 2 hours. After completion of the sweating treatment, the sweating liquid was discharged and used as the raw material for recrystallization in step 3). The sweated crystals were heated to 70° C. to completely melt, yielding pure decanediamine with a mass purity of 99.996%. The total yield of decanediamine was 37.68%.
[0049] The present invention uses crude decanediamine of different mass percentages as raw materials to carry out an inert gas bubbling coupled melt crystallization process, and the target purity can be achieved to obtain a pure decanediamine with a mass percentage of> 99.99%. When the raw material purity is lower than 90%, if ultra-high purity needs to be achieved, multi-stage suspension melt crystallization can be performed, but this will also cause problems with rising equipment and operating costs. Therefore, in order to obtain a pure decanediamine of target purity while reducing costs to the greatest extent, the present invention is preferentially applicable to the purification of crude decanediamine with a mass percentage of ≥70%, and is more effective for the purification of crude decanediamine with a mass percentage of ≥90%. In summary, the present invention has the advantages of automated continuous production, low production (cost is only 1 / 3 to 1 / 5 of layered melt crystallization), and high product purity and yield.
Claims
1. A method for preparing ultra-high purity decanediamine, characterized in that The steps include: 1) Under an inert gas atmosphere, the crude decanediamine is completely melted at 65-70° C., and then subjected to suspension melt crystallization with inert gas bubbling. During the crystallization process, the temperature is maintained constant after it drops to 40-60° C.; After the crystallization is completed, the slurry is subjected to solid-liquid separation to obtain a solid phase crude material of decanediamine; 2) completely melting the solid crude decanediamine obtained in step 1) at 65-70° C., and then performing layered melt crystallization with inert gas bubbling, gradually lowering the temperature to 55-61° C. and then maintaining the temperature constant during the crystallization process, and discharging the mother liquor after crystal growth is complete; 3) heating the crystals obtained in step 2) to sweat under an inert gas atmosphere, and discharging the sweating liquid after the sweating is completed; then completely melting the crystals at 65-70° C., and the melted product is a decanediamine product with a purity greater than 99.99%.
2. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: The flow rate of the inert gas introduced during the suspension melt crystallization process with inert gas bubbling is controlled at 0.01 to 2 L / min.
3. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: The flow rate of the inert gas introduced during the layered melt crystallization process with inert gas bubbling is controlled at 0.05 to 2 L / min.
4. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: In the step 1), the mass percentage of the crude decanediamine as the raw material is ≥70%; and the residence time of the suspension melt crystallization is 1 to 8 hours.
5. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: In the step 2), the cooling rate is 0.1 to 10 K / h; after cooling, the constant temperature is maintained for 0.5 to 2 hours.
6. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: In the step 3), the heating rate of the crystal during sweating is 0.1 to 30 K / h, the final temperature of the heating is 58 to 65° C., and the constant temperature time after heating to the final temperature is 0.5 to 2 h.
7. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: The step 1) further comprises the following operations: recrystallizing the liquid phase obtained by solid-liquid separation according to the crystallization method of this step until the mass percentage of decanediamine is less than 40%, and discharging the residual liquid.
8. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: The step 2) further comprises the following operations: collecting the mother liquor and performing recrystallization as the crystallization raw material of the step 1); The step 3) further comprises the following operation: collecting the sweat solution and performing recrystallization as the crystallization raw material of the step 2).
9. The method for preparing ultra-high-purity decanediamine according to claim 1, wherein: The step 1) further comprises the following operation: the obtained solid phase crude material of decanediamine is crystallized multiple times according to the crystallization method of this step.