Preparation method of nylon 512 salt

Abstract

The invention belongs to the technical field of material synthesis, and provides a preparation method of nylon 512 salt. The method comprises the following steps: mixing pentamethylene diamine and absolute ethyl alcohol to obtain a pentamethylene diamine ethanol solution; mixing dodecanedioic acid and a pentamethylene diamine ethanol solution, and reacting to obtain a nylon salt solution to be purified; and sequentially carrying out heating volatilization, cooling crystallization, suction filtration, washing and drying on the to-be-purified nylon salt solution to obtain the nylon 512 salt. A cooling crystallization process is adopted, the reaction conditions of the process are mild, and high temperature and high pressure are not needed, so that the energy consumption is reduced. Compared with the prior art, the technical scheme provided by the invention does not need inert gas protection and does not need to control the pH value in the reaction process, so that the whole salifying process is simpler, more convenient and easier to control.

Description

Technical Field

[0001] The invention relates to the technical field of material synthesis, and in particular to a method for preparing nylon 512 salt. Background Art

[0002] Nylon salt is an indispensable precursor in the preparation of nylon polymers and is crucial to ensuring the quality of the final nylon product. However, under the current technical level, the preparation process of nylon salt faces many challenges, such as high salt formation temperature, long time, easy yellowing, uneven particle size and high energy consumption. These problems have seriously hindered the further development and industrial application of nylon products. Therefore, the development of a low-cost and simple-to-operate process for the preparation of nylon 512 salt is crucial to achieve efficient production and widespread application of nylon products. Summary of the invention

[0003] In view of this, the present invention provides a method for preparing nylon 512 salt, the purpose of which is to solve the technical problems existing in the prior art such as high salt-forming temperature, long time, easy yellowing, uneven particle size and high energy consumption.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] The present invention provides a method for preparing nylon 512 salt, comprising the following steps:

[0006] S1, mixing pentamethylenediamine and anhydrous ethanol to obtain a pentamethylenediamine ethanol solution;

[0007] S2, mixing dodecanedioic acid and pentamethylenediamine ethanol solution and reacting them to obtain a nylon salt solution to be purified;

[0008] S3, heating the nylon salt solution to be purified to volatilize, cooling to crystallize, filtering, washing and drying in sequence to obtain nylon 512 salt.

[0009] Furthermore, in step S1, the mass volume ratio of pentamethylenediamine to anhydrous ethanol is 1-2 g:10-20 mL.

[0010] Furthermore, in step S1, the mixing temperature is 50-60°C.

[0011] Furthermore, in step S2, the reaction temperature is 40-60° C., and the reaction time is 1-4 hours.

[0012] Furthermore, the mass ratio of pentamethylenediamine to dodecanedioic acid is 1-2:3-5.

[0013] Furthermore, in step S3, the temperature of the heating volatilization is 50-60° C., and the time of the heating volatilization is 30-120 min.

[0014] Furthermore, in step S3, the temperature of the cooling crystallization is 1-5°C.

[0015] Furthermore, in step S3, the solvent used for washing includes anhydrous ethanol.

[0016] Furthermore, in step S3, the drying temperature is 60-80° C., and the drying time is 8-15 hours.

[0017] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The present invention adopts a cooling crystallization process, which has mild reaction conditions and does not require high temperature and high pressure, thereby reducing energy consumption. Compared with the prior art, the technical solution of the present invention does not require inert gas protection, nor does it require the pH value of the reaction process to be controlled (because in the prior art, most of the salt-forming processes require the use of a pH meter to monitor and control the pH), making the entire salt-forming process simpler and easier to control. DETAILED DESCRIPTION

[0019] The present invention provides a method for preparing nylon 512 salt, comprising the following steps:

[0020] S1, mixing pentamethylenediamine and anhydrous ethanol to obtain a pentamethylenediamine ethanol solution;

[0021] S2, mixing dodecanedioic acid and pentamethylenediamine ethanol solution and reacting them to obtain a nylon salt solution to be purified;

[0022] S3, heating the nylon salt solution to be purified to volatilize, cooling to crystallize, filtering, washing and drying in sequence to obtain nylon 512 salt.

[0023] In the present invention, in step S1, the mass volume ratio of pentamethylenediamine to anhydrous ethanol is 1-2 g:10-20 mL, preferably 1.2-1.8 g:12-18 mL, and more preferably 1.4-1.6 g:14-16 mL.

[0024] In the present invention, in the step S1, the mixing temperature is 50-60°C, preferably 52-58°C, and more preferably 54-56°C.

[0025] In the present invention, in step S2, the reaction temperature is 40 to 60°C, preferably 45 to 55°C, and more preferably 50°C; the reaction time is 1 to 4 hours, and preferably 2 to 3 hours.

[0026] In the present invention, the mass ratio of pentamethylenediamine to dodecanedioic acid is 1 to 2:3 to 5, preferably 1.2 to 1.8:3.5 to 4.5, and more preferably 1.4 to 1.6:4.

[0027] In the present invention, dodecanedioic acid can be divided into 1 to 4 parts and then added in batches.

[0028] In the present invention, in step S3, the temperature of the heating volatilization is 50-60°C, preferably 52-58°C, and more preferably 54-56°C; the time of the heating volatilization is 30-120 min, preferably 40-100 min, and more preferably 50-80 min.

[0029] In the present invention, in step S3, the temperature of the cooling crystallization is 1 to 5°C, preferably 2 to 4°C, and more preferably 3°C.

[0030] In the present invention, in step S3, the solvent used for washing includes anhydrous ethanol.

[0031] In the present invention, in step S3, the drying temperature is 60 to 80° C., preferably 65 to 75° C., and more preferably 70° C.; the drying time is 8 to 15 hours, and preferably 10 to 12 hours.

[0032] 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.

[0033] Example 1

[0034] Weigh 1.78g of pentamethylenediamine and dissolve it in 15mL of anhydrous ethanol. Stir it thoroughly under stirring in a water bath at 55°C to form an ethanol solution of pentamethylenediamine. Weigh 4.0g of dodecanedioic acid and add it to the ethanol solution of pentamethylenediamine at one time, react at 40°C for 4h to obtain a nylon salt solution to be purified. Stir the nylon salt solution to be purified at 55°C, heat it to volatilize the ethanol, and place it at 4°C for cooling and crystallization after stirring for 1h. After the crystals are precipitated, separate the solid and the liquid by suction filtration, wash the solid with anhydrous ethanol, and place the obtained nylon salt solid in a vacuum oven at 60°C and dry it for 12h to obtain nylon 512 salt. It is calculated that the product yield of this embodiment is 92%, and the nylon 512 salt has a good color and no odor.

[0035] Example 2

[0036] Weigh 1.4g of pentamethylenediamine and dissolve it in 15mL of anhydrous ethanol. Stir it thoroughly under stirring in a water bath at 55°C to form an ethanol solution of pentamethylenediamine. Weigh 3.5g of dodecanedioic acid, divide it into two parts, add it to the ethanol solution of pentamethylenediamine in batches, and react at 45°C for 3h to obtain a nylon salt solution to be purified. Stir the nylon salt solution to be purified at 55°C, heat it to volatilize the ethanol, and place it at 4°C for cooling and crystallization after stirring for 1h. After the crystals are precipitated, separate the solid and the liquid by suction filtration, wash the solid with anhydrous ethanol, and place the obtained nylon salt solid in a vacuum oven at 70°C and dry it for 11h to obtain nylon 512 salt. It is calculated that the product yield of this embodiment is 86%, and the nylon 512 salt has a good color and no odor.

[0037] Example 3

[0038] Weigh 1.6g of pentamethylenediamine and dissolve it in 20mL of anhydrous ethanol. Stir it thoroughly under stirring in a water bath at 55°C to form an ethanol solution of pentamethylenediamine. Weigh 4.5g of dodecanedioic acid, divide it into three parts, add it to the ethanol solution of pentamethylenediamine in batches, and react it at 50°C for 2h to obtain a nylon salt solution to be purified. Stir the nylon salt solution to be purified at 55°C, heat it to volatilize the ethanol, and place it at 3°C ​​for cooling and crystallization after stirring for 1h. After the crystals are precipitated, separate the solid and the liquid by suction filtration, wash the solid with anhydrous ethanol, and place the obtained nylon salt solid in a vacuum oven at 80°C and dry it for 10h to obtain nylon 512 salt. It is calculated that the product yield of this embodiment is 88%, and the nylon 512 salt has a good color and no odor.

[0039] 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 preparing nylon 512 salt, characterized in that: The following steps are involved: S1, mixing pentamethylenediamine and anhydrous ethanol to obtain a pentamethylenediamine ethanol solution; S2, mixing dodecanedioic acid and pentamethylenediamine ethanol solution and reacting them to obtain a nylon salt solution to be purified; S3, heating the nylon salt solution to be purified to volatilize, cooling to crystallize, filtering, washing and drying in sequence to obtain nylon 512 salt.

2. The preparation method according to claim 1, characterized in that: In the step S1, the mass volume ratio of pentamethylenediamine to anhydrous ethanol is 1-2 g:10-20 mL.

3. The preparation method according to claim 2, characterized in that: In the step S1, the mixing temperature is 50-60°C.

4. The preparation method according to any one of claims 1 to 3, characterized in that: In step S2, the reaction temperature is 40-60° C., and the reaction time is 1-4 hours.

5. The preparation method according to claim 4, characterized in that: The mass ratio of pentamethylenediamine to dodecanedioic acid is 1-2:3-5.

6. The preparation method according to claim 2, 3 or 5, characterized in that: In the step S3, the temperature of the heating volatilization is 50-60° C., and the time of the heating volatilization is 30-120 min.

7. The preparation method according to claim 6, characterized in that: In the step S3, the temperature of the cooling crystallization is 1-5°C.

8. The preparation method according to claim 7, characterized in that: In step S3, the solvent used for washing includes anhydrous ethanol.

9. The preparation method according to claim 8, characterized in that: In step S3, the drying temperature is 60-80° C., and the drying time is 8-15 hours.