阅读说明：本技术 一种eddha螯合铁盐的制备方法 (Preparation method of EDDHA chelated iron salt ) 是由 程雪莲 袁志文 李成果 李娟� 张伟 渠永娟 闫成会 于 2020-12-31 设计创作，主要内容包括：本发明涉及化学合成技术领域,具体公开一种EDDHA螯合铁盐的制备方法。所述EDDHA螯合铁盐的制备方法,包括以下工艺步骤：a、将苯酚加热至40-70℃,加入乙二胺和乙醛酸混合均匀,得到初始混合物料；b、向初始混合物料中加入乙醛酸和碱性水溶液,得到反应原料混合物；c、将反应原料混合物加热至60-90℃反应,用萃取溶剂对反应产物进行萃取,得到EDDHA盐溶液；d、EDDHA盐溶液与无机铁盐进行螯合反应得到EDDHA螯合铁盐溶液；e、将EDDHA螯合铁盐溶液进行浓缩、离心分离和烘干处理,得到EDDHA螯合铁盐。本发明提供的EDDHA螯合铁盐的制备方法可得到高纯度、高品质的EDDHA螯合铁盐。(The invention relates to the technical field of chemical synthesis, and particularly discloses a preparation method of EDDHA chelated iron salt. The preparation method of the EDDHA chelated iron salt comprises the following process steps: a. heating phenol to 40-70 ℃, adding ethylenediamine and glyoxylic acid, and uniformly mixing to obtain an initial mixed material; b. adding glyoxylic acid and an alkaline aqueous solution into the initial mixed material to obtain a reaction raw material mixture; c. heating the reaction raw material mixture to 60-90 ℃ for reaction, and extracting a reaction product by using an extraction solvent to obtain an EDDHA salt solution; d. carrying out chelation reaction on the EDDHA salt solution and inorganic iron salt to obtain an EDDHA chelated iron salt solution; e. and concentrating, centrifugally separating and drying the EDDHA chelated iron salt solution to obtain the EDDHA chelated iron salt. The preparation method of the EDDHA chelated iron salt can obtain the high-purity and high-quality EDDHA chelated iron salt.)

1. A preparation method of EDDHA chelated iron salt is characterized by comprising the following steps: the method comprises the following process steps:

a. heating phenol to 40-70 ℃, adding ethylenediamine and glyoxylic acid in a molar ratio of 1:0.8-1.2, and uniformly mixing to obtain an initial mixed material;

b. adding glyoxylic acid and an alkaline aqueous solution into the initial mixed material to obtain a reaction raw material mixture; the molar ratio of the glyoxylic acid to the hydroxide ions in the alkaline aqueous solution is 1: 1-1.05; the molar ratio of the glyoxylic acid to the ethylenediamine in the step a is 0.8-1.2: 1;

c. heating the reaction raw material mixture to 60-90 ℃ for reaction, extracting a reaction product by using an extraction solvent after the reaction is finished, and removing an organic phase to obtain an EDDHA salt solution;

d. under the condition that the pH value is 7.5-9, carrying out a chelating reaction on the EDDHA salt solution and inorganic iron salt to obtain an EDDHA chelated iron salt solution;

e. and concentrating, centrifugally separating and drying the EDDHA chelated iron salt solution to obtain the EDDHA chelated iron salt.

2. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step a, the molar ratio of the phenol to the ethylenediamine is 10-22: 1.

3. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step b, the alkaline aqueous solution is a sodium hydroxide solution or a potassium hydroxide solution with the mass concentration of 31-32%.

4. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step c, the reaction time is 1-5 h.

5. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step c, the extraction solvent is at least one of toluene, carbon tetrachloride and butyl acetate.

6. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step c, the mass ratio of the extraction solvent to the reaction product is 0.1-0.3: 1.

7. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step d, the inorganic salt is ferrous sulfate, and the mass ratio of the EDDHA salt solution to the ferrous sulfate is 18-19.2: 1.

8. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step d, the temperature of the chelation reaction is 30-50 ℃; and/or

In step d, the time of the chelation reaction is 1-2 h.

9. A method of preparing an EDDHA chelating iron salt as claimed in claim 1, wherein: in the step e, the solid-liquid mass ratio of the concentrated EDDHA chelated iron salt solution is 1: 1.4-2.

10. A method of preparing an EDDHA chelating ferric salt as claimed in claim 9, wherein: in step e, the separation factor of the centrifugation is controlled at 2950 of 1500-.

Technical Field

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of EDDHA chelated iron salt.

Background

Iron is one of 7 trace elements required by plant growth, and is a main preparation for curing diseases of plant lobules and yellow leaves. The iron-containing inorganic salt fertilizer applied conventionally has unstable properties, causes low use function, has destructive effect on soil, and is not beneficial to green agriculture and sustainable development. Therefore, the demand for soluble high-purity organic chelated iron fertilizer is urgent in agriculture.

The EDDHA chelated iron salt is high-efficiency, high-quality and super-strong active chelated iron, is used as a trace element fertilizer in agriculture, and is one of the most effective products for treating plant iron deficiency and yellow leaf disease. However, the method for producing EDDHA chelate iron salt uses phenol, ethylenediamine, glyoxylic acid and inorganic salt containing iron as raw materials, and EDDHA chelate iron salt is prepared under an alkaline environment provided by sodium hydroxide or potassium hydroxide, inorganic sodium salt or potassium salt is uncontrollably generated in the reaction process, the purity of EDDHA chelate iron salt is seriously affected by the presence of the inorganic salt, and the use of the poor EDDHA chelate iron salt can damage soil to a certain extent. Meanwhile, the high-quality EDDHA chelating iron salt product has higher requirement on the content of ortho-ortho value, namely when glyoxylic acid is combined with phenol, ortho-H of phenolic hydroxyl is involved in the reaction, but not para-H of the phenolic hydroxyl. However, no suitable production method is available at present to avoid the phenol hydroxyl para-H from participating in the reaction. The current method for preparing the EDDHA chelated iron salt still inevitably has a large amount of phenol hydroxyl para-H to participate in the reaction, and generates a large amount of corresponding impurities, thereby seriously influencing the purity of the EDDHA chelated iron salt. Therefore, how to ensure high purity and high quality of EDDHA chelating iron salts becomes one of the major problems in current research on chelating iron salts.

Disclosure of Invention

Aiming at the problems of the EDDHA chelated iron salt obtained by the existing preparation method, the invention provides the preparation method of the EDDHA chelated iron salt, and the high-purity EDDHA chelated iron salt can be obtained.

In order to achieve the purpose of the invention, the embodiment of the invention adopts the following technical scheme:

a preparation method of EDDHA chelated iron salt comprises the following process steps:

a. heating phenol to 40-70 ℃, adding ethylenediamine and glyoxylic acid in a molar ratio of 1:0.8-1.2, and uniformly mixing to obtain an initial mixed material;

b. adding glyoxylic acid and an alkaline aqueous solution into the initial mixed material to obtain a reaction raw material mixture; in the step, the molar ratio of the glyoxylic acid to the hydroxide ions in the alkaline aqueous solution is 1: 1-1.05; the molar ratio of the glyoxylic acid to the ethylenediamine in the step a is 0.8-1.2: 1;

c. heating the reaction raw material mixture to 60-90 ℃ for reaction, extracting a reaction product by using an extraction solvent after the reaction is finished, and removing an organic phase to obtain an EDDHA salt solution;

d. under the condition that the pH value is 7.5-9, carrying out chelation reaction on the EDDHA salt solution and inorganic iron salt to obtain an EDDHA chelated iron salt solution;

e. and concentrating, centrifugally separating and drying the EDDHA chelated iron salt solution to obtain the EDDHA chelated iron salt.

The prior method for preparing the EDDHA chelated iron salt can generate a large amount of inorganic sodium salt or potassium salt uncontrollably, and a large amount of phenol hydroxyl para-H inevitably participates in the reaction process, and generates a large amount of corresponding impurities, thereby seriously influencing the purity of the EDDHA chelated iron salt. Compared with the prior art, the preparation method of the EDDHA chelated iron salt provided by the invention adopts a two-step method to add glyoxylic acid, sets the adding sequence and the dosage of the ethylenediamine, the glyoxylic acid and the alkaline aqueous solution which are matched with each other, enables the materials to carry out preliminary reaction under different pH conditions, and then heats to 60-90 ℃, so that the ortho-H of the phenolic hydroxyl group in the reaction raw material mixture can be ensured to be combined with the glyoxylic acid, the obtained EDDHA salt contains a higher ortho-H value, and a large amount of impurities generated by the reaction of the para-H of the phenolic hydroxyl group can be obviously reduced. And then, after the organic phase in the reaction product is removed by extraction of the extraction solvent, the EDDHA salt in the water phase can avoid the interference of the organic phase in the process of chelating with the inorganic ferric salt, and the yield of the EDDHA chelated ferric salt can be obviously improved. And then, by utilizing the density difference between the EDDHA chelated iron salt and the inorganic salt, concentrating, centrifugally separating and drying the EDDHA chelated iron salt solution, the inorganic salt in the EDDHA chelated iron salt can be quickly removed, and the EDDHA chelated iron salt with high purity, high quality and high yield is obtained.

Preferably, in step a, the molar ratio of the phenol to the ethylenediamine is 10-22: 1.

Preferably, in step b, the alkaline aqueous solution is a sodium hydroxide solution or a potassium hydroxide solution with a mass concentration of 31-32%.

Preferably, in step c, the reaction time is 1-5 h.

Preferably, in step c, the extraction solvent is at least one of toluene, carbon tetrachloride and butyl acetate.

The selection of the extraction solvent can ensure that the content of phenol in the obtained EDDHA salt solution is less than 2 percent, further reduce the interference of the EDDHA salt solution on the subsequent chelating reaction, and further improve the yield of the EDDHA chelated iron salt.

Preferably, in step c, the mass ratio of the extraction solvent to the reaction product is 0.1-0.3: 1.

Preferably, in the step d, the inorganic salt is ferrous sulfate, and the mass ratio of the EDDHA salt solution to the ferrous sulfate is 18-19.2: 1.

Preferably, the temperature of the chelation reaction in step d is 30-50 ℃.

Preferably, in step d, the time for the chelation reaction is 1-2 h.

Preferably, in the step e, the solid-liquid mass ratio of the concentrated EDDHA chelated iron salt solution is 1: 1.4-2.

The EDDHA chelated iron salt solution obtained by the reaction is concentrated to the solid content, and then is centrifuged, and proper centrifugal force is controlled, so that the EDDHA chelated iron salt and the inorganic salt can be quickly and effectively separated.

Preferably, in step e, the separation factor of the centrifugation is controlled at 2950 of 1500-.

The selection of the centrifugal separation factor can ensure that the light-component inorganic salt and the heavy-component EDDHA chelating iron salt in the EDDHA chelating iron salt solution with the specific solid-liquid mass ratio have certain fluidity, so that the subsequent operation is facilitated. And simultaneously, the high-quality requirement of the heavy component EDDHA chelating iron salt is met.

Drawings

Fig. 1 is a process flow diagram of EDDHA chelating iron salt preparation in example 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A preparation method of EDDHA chelated iron salt comprises the following specific process steps:

564.66g of phenol was added into a 2000ml four-necked flask, and stirred and heated to 40 ℃ and 71.07g of 50 wt% glyoxylic acid and 36g of ethylenediamine were added dropwise at a constant rate for 1.5 h. 71.07g of 50 wt% glyoxylic acid and 75g of 32% alkaline solution (sodium hydroxide solution) are added dropwise at a constant speed at the same time after the end of the addition, and the addition time is 1.5 h. After the dropwise addition is finished, the temperature is raised to 60 ℃, and the temperature is kept for 5 hours to obtain a reaction product. And cooling the reaction product to 42 ℃, adding 540g of water, adding 67.89g of toluene, extracting the reaction product, stirring for 10min, standing for 10min, and separating liquid to obtain a water phase. This extraction was repeated two more times (33.95 g of toluene each time) and the aqueous phases from the three extractions were combined to give 820g of EDDHA-Na solution with an impurity content of 0.44%.

Heating the EDDHA-Na solution after extraction to 30 ℃, dropwise adding 241.22g of 18.75 wt% ferrous sulfate, controlling the pH value of the water phase to be between 8.0 and 8.5 in the dropwise adding process, controlling the dropwise adding temperature to be between 30 and 35 ℃, and controlling the dropwise adding time to be about 1.5 h. After the dropwise addition, the temperature is kept at 30 ℃ for 1h to obtain the chelating solution. Concentrating the chelating solution under negative pressure until the solid-liquid mass ratio is 1:2, and centrifugally settling under the condition that the centrifugal separation factor is 1500 to obtain the light-component inorganic salt and the heavy-component EDDHA chelating iron salt.

The heavy component and the light component are respectively dried to obtain 250.76g of heavy component EDDHA chelating iron salt with the purity of 99.48 percent. 50.74g of light component sodium sulfate, 15.254% of EDDHA chelated iron salt and 98.496% of total conversion rate of raw material ethylenediamine.

Example 2

A preparation method of EDDHA chelated iron salt comprises the following specific process steps:

847g of phenol was added to a 2000ml four-necked flask, the flask was heated to 50 ℃ with stirring, and 88.84g of 50 wt% glyoxylic acid and 36g of ethylenediamine were added dropwise at a uniform rate over 1.5 h. 88.84g of 50 wt% glyoxylic acid and 76.5g of 32% alkaline solution (sodium hydroxide solution) are simultaneously and uniformly added dropwise for 1.5h after the addition. After the dropwise addition, the temperature is raised to 75 ℃, and the temperature is kept for 3 hours to obtain a reaction product. And cooling the reaction product to 42 ℃, adding 540g of water, adding 167.72g of butyl acetate to extract the reaction product, stirring for 15min, standing for 15min, and separating liquid to obtain a water phase. The extraction process was repeated two more times (86.86 g of butyl acetate), and the aqueous phases obtained from the three extractions were combined to obtain 835g of EDDHA-Na solution with an impurity content of 0.37%.

Heating the EDDHA-Na solution after extraction to 40 ℃, dropwise adding 239.43g of 18.75 wt% ferrous sulfate, controlling the pH value of the water phase between 7 and 8 in the dropwise adding process, controlling the dropwise adding temperature between 35 and 40 ℃ and controlling the dropwise adding time to be about 1.5 h. After the dropwise addition, the temperature is kept at 40 ℃ for 1.5h to obtain the chelating solution. Concentrating the chelating solution under negative pressure until the solid-liquid mass ratio is 1:1.6, and centrifugally settling under the condition that the centrifugal separation factor is 2050 to obtain light-component inorganic salt and heavy-component EDDHA chelating iron salt.

The heavy component and the light component are respectively dried to obtain 253g of heavy component EDDHA chelated iron salt with the purity of 99.66%. 46.785g of light component sodium sulfate, 10.933 percent of EDDHA chelated iron salt and 98.520 percent of total conversion rate of raw material ethylenediamine.

Example 3

A preparation method of EDDHA chelated iron salt comprises the following specific process steps:

1242g of phenol is added into a 2000ml four-mouth bottle, stirred and heated to 70 ℃, and 106.6g of 50 wt% glyoxylic acid and 36g of ethylenediamine are added dropwise at a constant speed at the same time, wherein the adding time is 1.5 h. 106.6g of 50 wt% glyoxylic acid and 78.75g of 32% alkaline solution (sodium hydroxide solution) are simultaneously and uniformly added dropwise for 1.5h after the addition. After the dropwise addition, the temperature is raised to 90 ℃, and the temperature is kept for 1h to obtain a reaction product. And cooling the reaction product to 42 ℃, adding 540g of water, adding 316.5g of carbon tetrachloride to extract the reaction product, stirring for 20min, standing for 20min, and separating liquid to obtain a water phase. The extraction process was repeated two more times (158.25 g of carbon tetrachloride each time), and the aqueous phases obtained from the three extractions were combined to obtain 870g of EDDHA-Na solution with an impurity content of 0.41%.

Heating the EDDHA-Na solution after extraction to 50 ℃, dropwise adding 241.67g of 18.75 wt% ferrous sulfate, controlling the pH value of the water phase to be between 8.5 and 9 in the dropwise adding process, controlling the dropwise adding temperature to be between 45 and 50 ℃, and controlling the dropwise adding time to be about 1.5 h. After the dropwise addition, the temperature is kept at 50 ℃ for 2h to obtain the chelating solution. Concentrating the chelating solution under negative pressure until the solid-liquid mass ratio is 1:1.4, and centrifugally settling under the condition that the centrifugal separation factor is 2950 to obtain light-component inorganic salt and heavy-component EDDHA chelating iron salt.

The heavy component and the light component are respectively dried to obtain 248g of heavy component EDDHA chelated iron salt with the purity of 99.70%. 52.5g of light component sodium sulfate, 19.379 percent of EDDHA chelated iron salt and 98.588 percent of total conversion rate of raw material ethylenediamine.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.