Method for synthesizing nylon salt from 1, 5-pentamethylene diamine

Abstract

The invention belongs to the technical field of pentamethylene diamine separation, and provides a method for synthesizing nylon salt from 1, 5-pentamethylene diamine. The method comprises the following steps: mixing a free 1, 5-pentamethylene diamine solution and n-butyl alcohol, and sequentially standing and separating liquid to obtain an extraction phase; performing reduced-pressure rotary evaporation on the extraction phase to obtain a mixed solution; the mixed solution comprises n-butyl alcohol, water and 1, 5-pentanediamine; and mixing the mixed solution with the adipic acid solution, reacting the mixture, and cooling and crystallizing to obtain the nylon salt. The extraction agent can be simultaneously used as a reaction solvent and can directly react in an extraction phase, so that the purification step is omitted, the repeated operation of purifying the pentamethylene diamine from the solvent and adding the pentamethylene diamine back to the solvent is avoided, and the salt forming process is simplified.

Description

Technical Field

[0001] The invention relates to the technical field of pentamethylenediamine separation, and in particular to a method for synthesizing nylon salt from 1,5-pentamethylenediamine. Background Art

[0002] It is a common method to use an extractant to separate 1,5-pentanediamine from the fermentation broth. Pentanediamine is enriched in the extract phase. Similar methods usually use distillation and other methods to separate pentanediamine with higher purity, and then add it to a solvent to react with a dibasic acid to synthesize nylon salt. There is also a method of adding a dibasic acid to the fermentation broth to form a nylon salt and then separating it, but the fermentation broth has a complex composition and the separated salt has low purity.

[0003] The purified 1,5-pentanediamine and dibasic acid usually need to be dissolved in water or alcohol before being recrystallized when synthesizing nylon salts. Figure 1 As shown, from the perspective of 1,5-pentanediamine, it is equivalent to spending a lot of manpower and material resources to extract pentamethylenediamine from water or alcohol and then dissolve it back. Therefore, it is of great significance to obtain a method for directly synthesizing nylon salt from 1,5-pentanediamine, which has a simple process, shortens the salt-forming steps, and improves the purity of nylon salt. Summary of the invention

[0004] The purpose of the present invention is to provide a method for synthesizing nylon salt from 1,5-pentanediamine in order to overcome the deficiencies of the prior art and solve the problem that the process of separating pentamethylenediamine from the synthesized nylon salt is complicated and there are useless steps.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for synthesizing nylon salt from 1,5-pentanediamine, comprising the following steps:

[0007] 1) mixing the free 1,5-pentanediamine solution and n-butanol, allowing the mixture to stand and separating the mixture to obtain an extract phase;

[0008] 2) performing rotary evaporation on the extract phase under reduced pressure to obtain a mixed solution; the mixed solution comprises n-butanol, water and 1,5-pentanediamine;

[0009] 3) The mixed solution is mixed with adipic acid solution, and the mixture is reacted and then cooled and crystallized to obtain nylon salt.

[0010] Preferably, the free 1,5-pentanediamine solution in step 1) comprises a mixture of a 1,5-pentanediamine salt solution and an alkali, a 1,5-pentanediamine fermentation broth or a 1,5-pentanediamine aqueous solution.

[0011] Preferably, in step 1), the volume ratio of the free 1,5-pentanediamine solution to n-butanol is 1:1-5.

[0012] Preferably, the mixing in step 1) is oscillating mixing or stirring mixing, the mixing rate is 40 to 60 r / min, and the mixing time is 0.5 to 1.5 h;

[0013] The standing temperature is 45-55° C., and the standing time is 3-5 hours.

[0014] Preferably, the pressure of the reduced pressure rotary evaporation in step 2) is 10 to 101.3 kPa, the temperature is 100 to 200° C., and the rotation speed is 10 to 50 rpm.

[0015] Preferably, in the adipic acid solution of step 3), the mass fraction of adipic acid is 1-50%, and in the mixture, the molar ratio of 1,5-pentanediamine to adipic acid is 0.5-1.5:0.5-1.5.

[0016] Preferably, the reaction time in step 3) is 0.5 to 5 h, and the reaction temperature is 20 to 30°C.

[0017] Preferably, the mixing temperature in step 3) is 40-50°C, and the cooling crystallization temperature is -20-0°C.

[0018] The beneficial effects of the present invention include the following:

[0019] 1) In the present invention, after the extraction phase is subjected to reduced pressure rotary evaporation, a dibasic acid is added to carry out a salt-forming reaction to synthesize nylon salt, and the reaction can be directly carried out in the extraction phase containing water and alcohol, thereby shortening the salt-forming process. After the reaction is completed, nylon salt crystals are obtained by cooling crystallization and the like.

[0020] 2) The extractant of the present invention has a high extraction efficiency for pentamethylenediamine; there are fewer impurities after extraction or after simple treatment of the extraction phase; it can be used as a reaction solvent for synthesizing nylon salt without reacting with two components. The extractant of the present invention can also be used as a reaction solvent, can react directly in the extraction phase, saves the purification step, simplifies the process steps of synthesizing nylon salt from 1,5-pentamethylenediamine, and reduces costs and increases efficiency.

[0021] 3) The extractant of the present invention is used to extract 1,5-pentanediamine in the free 1,5-pentanediamine solution to obtain an extract phase with simple components, thereby avoiding the repeated operation of purifying pentamethylenediamine from the solvent and adding it back into the solvent, and simplifying the salt-forming process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The invention relates to a salt-forming process for synthesizing nylon salt from pentamethylenediamine fermentation broth in the prior art;

[0023] Figure 2 The invention provides a salt-forming process for synthesizing nylon salt from a free 1,5-pentanediamine solution;

[0024] Figure 3 is a photograph of the nylon 56 salt crystals of Example 1;

[0025] Figure 4 This is the XRD pattern of the nylon 56 salt crystal of Example 1. DETAILED DESCRIPTION

[0026] The present invention provides a method for synthesizing nylon salt from 1,5-pentanediamine, comprising the following steps:

[0027] 1) mixing the free 1,5-pentanediamine solution and n-butanol, allowing the mixture to stand and separating the mixture to obtain an extract phase;

[0028] 2) performing rotary evaporation on the extract phase under reduced pressure to obtain a mixed solution; the mixed solution comprises n-butanol, water and 1,5-pentanediamine;

[0029] 3) The mixed solution is mixed with adipic acid solution, and the mixture is reacted and then cooled and crystallized to obtain nylon salt.

[0030] In the present invention, the free 1,5-pentanediamine solution in step 1) preferably comprises a mixture of a 1,5-pentanediamine salt solution and an alkali, a 1,5-pentanediamine fermentation broth or a 1,5-pentanediamine aqueous solution.

[0031] In the present invention, the components of the free 1,5-pentanediamine solution include, but are not limited to, 1,5-pentanediamine, water, bacterial residues, inorganic salts, alkaline substances and hydrophilic solvents.

[0032] In the present invention, the volume ratio of the free 1,5-pentanediamine solution and n-butanol in step 1) is preferably 1:1-5, more preferably 1:2-4, and more preferably 1:3.

[0033] In the present invention, the mixing in step 1) is preferably shaking mixing or stirring mixing, the mixing rate is preferably 40 to 60 r / min, more preferably 45 to 55 r / min, more preferably 50 r / min, and the mixing time is preferably 0.5 to 1.5 h, more preferably 0.8 to 1.2 h, more preferably 1.0 h;

[0034] The standing temperature is preferably 45 to 55° C., more preferably 48 to 52° C., and more preferably 50° C.; the standing time is preferably 3 to 5 h, more preferably 3.5 to 4.5 h, and more preferably 4.0 h.

[0035] When the extract phase of the present invention contains a small amount of dissolved salt, desalination is performed by filtration, centrifugation, rotary evaporation, etc.

[0036] In the present invention, the pressure of the reduced pressure rotary evaporation in step 2) is preferably 10 to 101.3 kPa, more preferably 30 to 80 kPa, and more preferably 50 to 60 kPa; the temperature of the reduced pressure rotary evaporation is preferably 100 to 200°C, more preferably 120 to 180°C, and more preferably 140 to 150°C; the rotation speed of the reduced pressure rotary evaporation is preferably 10 to 50 rpm, more preferably 20 to 40 rpm, and more preferably 30 rpm.

[0037] In the present invention, in the adipic acid solution of step 3), the mass fraction of adipic acid is preferably 1-50%, more preferably 10-40%, and more preferably 20-30%; in the mixture, the molar ratio of 1,5-pentanediamine to adipic acid is preferably 0.5-1.5:0.5-1.5, more preferably 0.8-1.2:0.8-1.2, and more preferably 1:1.

[0038] In the present invention, the adipic acid solution in step 3) is an aqueous solution of adipic acid.

[0039] In the present invention, the reaction time of step 3) is preferably 0.5 to 5 h, more preferably 1 to 4 h, more preferably 2 to 3 h; the reaction temperature is preferably 20 to 30° C., more preferably 22 to 28° C., more preferably 24 to 25° C.

[0040] In the present invention, the mixing temperature in step 3) is preferably 40 to 50°C, more preferably 42 to 48°C, and more preferably 45 to 46°C; the cooling crystallization temperature is preferably -20 to 0°C, more preferably -15 to -5°C, and more preferably -10°C.

[0041] The salt-forming process of synthesizing nylon salt from free 1,5-pentanediamine solution of the present invention is as follows: Figure 2 shown.

[0042] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0043] Example 1

[0044] The free 1,5-pentanediamine fermentation broth is added to n-butanol (the volume ratio of the free 1,5-pentanediamine fermentation broth to n-butanol is 1:3), the free 1,5-pentanediamine fermentation broth contains 1,5-pentanediamine (the concentration of 1,5-pentanediamine in the fermentation broth is 1.5 mol / L), water, bacterial residues such as Escherichia coli (concentration is 80 g / L), sodium chloride (concentration is 170 g / L), a small amount of sodium hydroxide and inorganic salts added during fermentation (concentration is 20 g / L), and the mixture is stirred and mixed at a rate of 50 r / min for 1 hour. The mixed solution is placed in a separating funnel and allowed to stand at 50° C. for 4 hours before separation to obtain an extraction phase.

[0045] The extract phase was subjected to reduced pressure rotary evaporation under the conditions of 50 kPa pressure, 150 ° C temperature and 30 rpm speed to remove non-volatile components, and a pure liquid mixture of n-butanol, water and 1,5-pentanediamine was obtained. The mixture was added dropwise to adipic acid solution (the mass fraction of adipic acid was 20%) at 45 ° C to obtain a mixture, in which the molar ratio of 1,5-pentanediamine to adipic acid was 1:1. After the mixture was reacted at 25 ° C for 3 hours, it was cooled and crystallized at -20 ° C to obtain nylon 56 salt crystals.

[0046] The photo of the nylon 56 salt crystals of Example 1 is shown in FIG. Figure 3 As shown; the XRD pattern of the nylon 56 salt crystal of Example 1 is as shown Figure 4 shown.

[0047] Example 2

[0048] An aqueous solution of 1,5-pentanediamine was added to n-butanol (the volume ratio of the aqueous solution of 1,5-pentanediamine and n-butanol was 1:2), wherein the aqueous solution of 1,5-pentanediamine contained 1,5-pentanediamine (the concentration of 1,5-pentanediamine in the aqueous solution was 1.2 mol / L), water, bacterial residues such as Escherichia coli (concentration was 50 g / L), sodium chloride (concentration was 150 g / L), a small amount of sodium hydroxide and inorganic salts added during fermentation (concentration was 5 g / L), and the mixture was stirred and mixed at a rate of 45 r / min for 1.5 h. The mixture was placed in a separating funnel and allowed to stand at 45° C. for 4.5 h before separation to obtain an extract phase.

[0049] The extract phase was subjected to reduced pressure rotary evaporation under the conditions of 10 kPa pressure, 120 ° C temperature and 20 rpm speed to remove non-volatile components, and a pure liquid mixture of n-butanol, water and 1,5-pentanediamine was obtained. The mixture was directly poured into adipic acid solution (the mass fraction of adipic acid was 10%) at 42 ° C to obtain a mixture, in which the molar ratio of 1,5-pentanediamine to adipic acid was 1.2:0.8. After the mixture was reacted at 22 ° C for 4 hours, it was cooled and crystallized at -15 ° C to obtain nylon 56 salt crystals.

[0050] Example 3

[0051] A mixture of 1,5-pentanediamine salt solution and alkali is added to n-butanol (the volume ratio of the mixture of 1,5-pentanediamine salt solution and alkali to n-butanol is 1:4), the mixture of 1,5-pentanediamine salt solution and alkali containing 1,5-pentanediamine (the concentration of 1,5-pentanediamine in the mixture is 1.8 mol / L), water, bacterial residues such as Escherichia coli (concentration is 90 g / L), sodium chloride (concentration is 180 g / L), a small amount of sodium hydroxide and inorganic salts added during fermentation (concentration is 20 g / L), and the mixture is stirred and mixed at a rate of 55 r / min for 0.8 h. The mixture is placed in a separating funnel and allowed to stand at 55° C. for 3.5 h before separation to obtain an extract phase.

[0052] The extract phase was subjected to reduced pressure rotary evaporation under the conditions of 80 kPa pressure, 180 ° C temperature and 40 rpm speed to remove non-volatile components, and a pure liquid mixture of n-butanol, water and 1,5-pentanediamine was obtained. The mixture was added to adipic acid solution (the mass fraction of adipic acid was 40%) at 48 ° C to obtain a mixture, in which the molar ratio of 1,5-pentanediamine to adipic acid was 0.8:1.2. The mixture was reacted at 28 ° C for 2 hours and then cooled and crystallized at -10 ° C to obtain nylon 56 salt crystals.

[0053] In the prior art, the method for synthesizing nylon salt from 1,5-pentanediamine is to increase the purity of pentamethylenediamine to more than 99.5% by extractive distillation, and then react with dibasic acid in water or alcohol solvent to form salt. The method of the present invention transfers pentamethylenediamine to an extraction phase to form a pentamethylenediamine solution with relatively simple components, removes impurities from the extraction phase, and then adds dibasic acid to react with it to form nylon salt with high purity. The present invention can directly react in an extraction phase containing water and alcohol, shortening the salt-forming process. After the reaction is completed, nylon salt crystals with high purity are obtained by cooling and crystallizing at -20 to 0°C.

[0054] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synthesizing nylon salt from 1,5-pentanediamine, characterized in that: The following steps are included: 1) mixing the free 1,5-pentanediamine solution and n-butanol, allowing the mixture to stand and separating the mixture to obtain an extract phase; 2) performing rotary evaporation on the extract phase under reduced pressure to obtain a mixed solution; the mixed solution comprises n-butanol, water and 1,5-pentanediamine; 3) The mixed solution is mixed with adipic acid solution, and the mixture is reacted and then cooled and crystallized to obtain nylon salt.

2. The method according to claim 1, characterized in that In step 1), the free 1,5-pentanediamine solution comprises a mixture of a 1,5-pentanediamine salt solution and an alkali, a 1,5-pentanediamine fermentation broth or a 1,5-pentanediamine aqueous solution.

3. The method according to claim 1 or 2, characterized in that: In step 1), the volume ratio of the free 1,5-pentanediamine solution to n-butanol is 1:1-5.

4. The method according to claim 3, characterized in that Step 1) The mixing is performed by shaking or stirring, the mixing rate is 40 to 60 r / min, and the mixing time is 0.5 to 1.5 h; The standing temperature is 45-55° C., and the standing time is 3-5 hours.

5. The method according to claim 4, characterized in that Step 2) The pressure of the reduced pressure rotary evaporation is 10 to 101.3 kPa, the temperature is 100 to 200° C., and the rotation speed is 10 to 50 rpm.

6. The method according to claim 5, characterized in that In step 3), the mass fraction of adipic acid in the adipic acid solution is 1-50%, and the molar ratio of 1,5-pentanediamine to adipic acid in the mixture is 0.5-1.5:0.5-1.

5.

7. The method according to claim 6, characterized in that Step 3) The reaction time is 0.5 to 5 hours, and the reaction temperature is 20 to 30°C.

8. The method according to claim 6 or 7, characterized in that: Step 3) The mixing temperature is 40 to 50°C, and the cooling crystallization temperature is -20 to 0°C.

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