Preparation method and application of cobalt acetate

Abstract

The invention belongs to the technical field of chemical engineering, and particularly relates to a preparation method and application of cobalt acetate, and the method comprises the following steps: putting metal cobalt into a reaction kettle; the method comprises the following steps: mixing acetic acid, hydrogen peroxide and water according to the mass ratio of 1: 1: (6-10), reacting metal cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at the temperature of 90-100 DEG C under the air condition, and filtering to obtain cobalt acetate. Acetic acid, hydrogen peroxide and water are firstly mixed and then react with metal cobalt, so that the cobalt content in cobalt acetate is increased, the impurity content is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and particularly relates to a preparation method and application of cobalt acetate. Background Art

[0002] Cobalt acetate (chemical formula: Co(CH3COO)2) is an important compound with a variety of functions and applications, mainly including: Catalyst: Cobalt acetate is often used as a catalyst in organic synthesis, especially in certain polymerization reactions, and can accelerate the rate of chemical reactions. Pigments: Cobalt acetate can be used to make blue pigments (such as cobalt blue), which are widely used in coatings, ceramics, and plastics. Nutritional supplements: In animal feed, cobalt acetate can be used as a cobalt supplement to promote animal growth and health, especially in the synthesis of vitamin B12. Battery materials: Cobalt acetate has applications in battery materials, especially in cathode materials for lithium-ion batteries and nickel-metal hydride batteries. Biochemical research: In biochemical experiments, cobalt acetate can be used as an activator for certain enzymes.

[0003] The following methods are usually used to prepare cobalt acetate in the prior art:

[0004] (1) Nitric acid method, which usually uses cobalt oxide as raw material and reacts with nitric acid. During the production process of this method, the raw material cobalt oxide contains a lot of impurities, resulting in a low cobalt content in the prepared reaction solution. In addition, this method has high energy consumption, high cost, and a great impact on the environment, and is not suitable for popularization and application.

[0005] (2) Oxygen or air method: oxygen or air is blown into the reactor under the action of a catalyst to prepare cobalt acetate by the reaction of cobalt and acetic acid. However, this preparation method has low efficiency, long reaction time and low cobalt content in the reaction solution.

[0006] In summary, although cobalt acetate has important applications in many fields, the shortcomings in its preparation process also limit the efficiency and sustainability of its production. In view of these problems, it is urgent to increase the cobalt content and reduce the impurity content in the reaction solution in the process of preparing cobalt acetate. Summary of the invention

[0007] The purpose of the present invention is to solve the deficiencies in the prior art and provide a preparation method and application of cobalt acetate.

[0008] In order to achieve the above object, the present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing cobalt acetate, the method comprising the following steps:

[0010] Step S1, adding metallic cobalt into a reaction kettle;

[0011] Step S2, mixing acetic acid, hydrogen peroxide and water in a mass ratio of 1:1:6-10,

[0012] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 90° C.-100° C. under air conditions, and obtaining cobalt acetate after filtering.

[0013] Preferably, the metallic cobalt is a mixture of flake metallic cobalt and spherical metallic cobalt, and the mass ratio thereof is 1:1-5.

[0014] Preferably, before preparing cobalt acetate, the metal cobalt is hot rolled at 700° C.-800° C., and then annealed at 700° C.-800° C. for 0.5 h-1 h.

[0015] Preferably, before preparing cobalt acetate, the metal cobalt is pretreated, and the pretreatment steps are as follows:

[0016] First, the straw is cut into small pieces of equal length, then a sodium hydroxide solution is added and immersed in a vacuum for 12 hours to 24 hours, then it is washed with ultrapure water until it is neutral, then it is vacuum immersed in a hydrochloric acid solution for 12 hours to 24 hours, and it is washed with ultrapure water until it is neutral, and finally, it is vacuum freeze-dried to obtain freeze-dried straw, and the freeze-dried straw is ground into powder;

[0017] The metal cobalt is reacted with nitric acid and then added with powder ground from freeze-dried straw to obtain pretreated metal cobalt.

[0018] Preferably, the mass fraction of the sodium hydroxide solution is 4%-5%.

[0019] Preferably, the mass fraction of the hydrochloric acid is 6%-8%.

[0020] Preferably, the freezing temperature is 70°C-80°C, and the freezing time is 24h-48h.

[0021] Preferably, in step S2, the mass fraction of acetic acid is 1%-3%, and the mass fraction of hydrogen peroxide is 6%-10%.

[0022] In a second aspect, the present invention provides an application of cobalt acetate in a catalyst.

[0023] Furthermore, the catalyst is a catalyst for preparing terephthalic acid from p-xylene by oxidation or a catalyst for preparing trimellitic anhydride from trimellitic anhydride.

[0024] The invention has the following beneficial effects: the invention adopts a mixture of sheet metal cobalt and spherical metal cobalt to replace the traditional method of using cobalt oxide or metal cobalt flakes to prepare cobalt acetate, and acetic acid, hydrogen peroxide and water are first mixed to increase the cobalt content in the prepared cobalt acetate reaction solution, thereby improving the preparation efficiency; in addition, the metal cobalt is pretreated before preparing the cobalt acetate, thereby further increasing the cobalt content in the prepared cobalt acetate reaction solution, reducing the impurity content, improving the reaction efficiency, reducing the concentration of the used acetic acid and hydrogen peroxide, and reducing the cost. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0026] Example 1

[0027] Step S1, adding metal cobalt (m (sheet metal cobalt 9995) and m (spherical metal cobalt) = 1:1) into a reaction kettle;

[0028] Step S2, acetic acid, hydrogen peroxide and water are mixed according to a mass ratio of 3% acetic acid, 10% hydrogen peroxide and water of 1:1:6.

[0029] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 90° C. under air conditions, and obtaining cobalt acetate after filtering.

[0030] Example 2

[0031] Step S1, adding metal cobalt (m (sheet metal cobalt 9995) and m (spherical metal cobalt) = 1:5) into a reaction kettle;

[0032] Step S2, acetic acid, hydrogen peroxide and water are mixed according to a mass ratio of 3% acetic acid, 10% hydrogen peroxide and water of 1:1:10.

[0033] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 100° C. under air conditions, and obtaining cobalt acetate after filtering.

[0034] Example 3

[0035] Step S1, hot rolling the cobalt sheet at 700° C., then annealing at 700° C. for 0.5 h, and then putting the pretreated metal cobalt (cobalt sheet) into a reactor;

[0036] Step S2, mixing acetic acid, hydrogen peroxide and water according to a mass ratio of 2% acetic acid, 8% hydrogen peroxide and water of 1:1:6,

[0037] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 95° C. under air conditions, and obtaining cobalt acetate after filtering.

[0038] Example 4

[0039] Step S1, hot rolling metal cobalt (m (sheet metal cobalt 9995) and m (spherical metal cobalt) = 1:5) at 800° C., and then annealing at 800° C. for 1 hour, and then putting the pretreated metal cobalt into a reactor;

[0040] Step S2, mixing acetic acid, hydrogen peroxide and water according to a mass ratio of 2% acetic acid, 8% hydrogen peroxide and water of 1:1:6,

[0041] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 95° C. under air conditions, and obtaining cobalt acetate after filtering.

[0042] Example 5

[0043] Step S1, first cutting the straw into small pieces of equal length, then adding a 5% by mass sodium hydroxide solution and immersing it in a vacuum for 12 hours, then washing it with ultrapure water until it is neutral, then vacuum immersing it in an 8% by mass hydrochloric acid solution for 12 hours, washing it with ultrapure water until it is neutral, and finally, vacuum freeze drying it at 70° C. to obtain freeze-dried straw, and grinding the freeze-dried straw into powder;

[0044] The metal cobalt (m(flaky metal cobalt 9995) and m(spherical metal cobalt)=1:5) was reacted with nitric acid and then added with freeze-dried straw powder to obtain pretreated metal cobalt;

[0045] Then the pretreated metallic cobalt is put into the reactor;

[0046] Step S2, mixing acetic acid, hydrogen peroxide and water according to the mass ratio of 1% acetic acid, 6% hydrogen peroxide and water being 1:1:6,

[0047] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 95° C. under air conditions, and obtaining cobalt acetate after filtering.

[0048] Example 6

[0049] Step S1, first cutting the straw into small pieces of equal length, then adding a sodium hydroxide solution with a mass fraction of 5% and immersing it in a vacuum for 24 hours, then washing it with ultrapure water until it is neutral, then vacuum immersing it in a hydrochloric acid solution with a mass fraction of 8% for 24 hours, washing it with ultrapure water until it is neutral, and finally, vacuum freeze drying it at 80° C. to obtain freeze-dried straw, and grinding the freeze-dried straw into powder;

[0050] The metal cobalt (m(flaky metal cobalt 9995) and m(spherical metal cobalt)=1:5) was reacted with nitric acid and then added with freeze-dried straw powder to obtain pretreated metal cobalt;

[0051] Then the pretreated metallic cobalt is put into the reactor;

[0052] Step S2, mixing acetic acid, hydrogen peroxide and water according to the mass ratio of 1% acetic acid, 6% hydrogen peroxide and water being 1:1:6,

[0053] Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 95° C. under air conditions, and obtaining cobalt acetate after filtering.

[0054] Comparative Example 1

[0055] Cobalt oxide is used as a raw material, reacted with nitric acid to obtain a cobalt nitrate solution, which is then reacted with a soda ash solution to generate a cobalt carbonate precipitate, which is washed and separated, and then acetic acid is added for acidification. The reaction solution is filtered, the pH is adjusted, and concentrated to obtain cobalt acetate, which is then recrystallized and centrifuged to obtain a finished cobalt acetate product.

[0056] Comparative Example 2

[0057] In a cylindrical reactor with a reflux device, 150 g of acetic anhydride, 20.0 g of cobalt powder, and 1.0 g of a composite catalyst (including 0.7 g of hydroquinone and 0.3 g of potassium persulfate) were added. At normal pressure, 0.12 m of air was blown in. 3 / h, keep the reaction temperature at 55-75°C, react for 90 minutes, filter and separate the pink cobalt salt intermediate product insoluble in acetic anhydride after the reaction is completed, then add distilled water, stir and dissolve, filter again, adjust the pH value of the obtained filtrate to 5.5 with acetic acid, and prepare cobalt acetate solution. The filtrate is returned to the column reactor for recycling.

[0058] The cobalt acetate prepared in Examples 1-6 and Comparative Examples 1-2 was tested for quality, and the results are shown in Table 1;

[0059] Table 1 Comparison of the quality of the products of the embodiments and comparative examples

[0060] Cobalt content% Iron content% Nickel content% Copper content% Zinc content% Example 1 97.5 0.001 0.01 0.0005 0.003 Example 2 97.6 0.0008 0.009 0.0004 0.002 Example 3 98.6 0.0005 0.0005 0.0002 0.001 Example 4 98.8 0.0006 0.0003 0.0003 0.001 Example 5 99.7 0.0004 0.0003 0.0002 0.002 Example 6 99.6 0.0005 0.0004 0.0003 0.001 Comparative Example 1 94.5 0.05 0.06 0.01 0.09 Comparative Example 2 95.0 0.006 0.05 0.008 0.06

[0061] As can be seen from Table 1, the cobalt content in the cobalt acetate product prepared by using cobalt oxide as a raw material in Comparative Example 1 is not high, and it contains more impurities, especially a high iron content. In order to obtain purer cobalt acetate, the energy consumption is large, the cost is high, and there is a great impact on the environment, which is not conducive to industrial production. Compared with Comparative Example 1, the conditions in Comparative Example 2 are milder. Compared with Examples 1 and 2, cobalt powder is first reacted with acetic anhydride before catalysis, while in this embodiment, acetic acid, hydrogen peroxide and water are mixed before reacting with metallic cobalt, thereby shortening the reaction time and increasing the cobalt content in the reaction solution. Improve the production efficiency; Example 1 and Example 1 use a mixture of flake metal cobalt 9995 and spherical metal cobalt to adjust the concentration of the prepared cobalt acetate, and the cobalt content in the reaction solution is relatively high. Examples 3-6 all pre-treat the metal cobalt flakes, further increasing the cobalt content in the reaction solution, reducing impurities such as iron, nickel, and copper, and improving the production efficiency. At the same time, according to Examples 3-6, the metal cobalt pre-treated by Examples 5 and Example 6 can reduce the mass fraction of acetic acid and hydrogen peroxide while ensuring the cobalt content, thereby reducing costs.

[0062] The above shows and describes the basic principles, main features and advantages of the present invention. However, the above is only a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other implementation methods derived by any technician in the field without departing from the technical solution of the present invention should be included in the patent scope of the present invention.

Claims

1. A method for preparing cobalt acetate, characterized in that: The method comprises the following steps: Step S1, adding metallic cobalt into a reaction kettle; Step S2, mixing acetic acid, hydrogen peroxide and water in a mass ratio of 1:1:6-10, Step S3, reacting metallic cobalt with a mixed solution of acetic acid, hydrogen peroxide and water at a temperature of 90° C.-100° C. under air conditions, and obtaining cobalt acetate after filtering.

2. The method for preparing cobalt acetate according to claim 1, characterized in that The metal cobalt is a mixture of flake metal cobalt and spherical metal cobalt, and the mass ratio thereof is 1:1-5.

3. The method for preparing cobalt acetate according to claim 1, characterized in that Before preparing cobalt acetate, the metal cobalt is hot rolled at 700° C.-800° C., and then annealed at 700° C.-800° C. for 0.5 h-1 h.

4. The method for preparing cobalt acetate according to claim 1, characterized in that Before preparing cobalt acetate, the metal cobalt is pretreated, and the steps of the pretreatment are as follows: First, the straw is cut into small pieces of equal length, then a sodium hydroxide solution is added and immersed in a vacuum for 12 hours to 24 hours, then it is washed with ultrapure water until it is neutral, then it is vacuum immersed in a hydrochloric acid solution for 12 hours to 24 hours, and it is washed with ultrapure water until it is neutral, and finally, it is vacuum freeze-dried to obtain freeze-dried straw, and the freeze-dried straw is ground into powder; The metal cobalt is reacted with nitric acid and then added with powder ground from freeze-dried straw to obtain pretreated metal cobalt.

5. The method for preparing cobalt acetate according to claim 4, characterized in that: The mass fraction of the sodium hydroxide solution is 4%-5%.

6. The method for preparing cobalt acetate according to claim 4, characterized in that: The mass fraction of the hydrochloric acid is 6%-8%.

7. The method for preparing cobalt acetate according to claim 4, characterized in that: The freezing temperature is 70°C-80°C, and the freezing time is 24h-48h.

8. The method for preparing cobalt acetate according to claim 1, characterized in that: In step S2, the mass fraction of acetic acid is 1%-3%, and the mass fraction of hydrogen peroxide is 6%-10%.

9. An application of cobalt acetate in a catalyst, characterized in that: The cobalt acetate is prepared by the method according to any one of claims 1 to 8.

10. The use according to claim 9, characterized in that: The catalyst is a catalyst for preparing terephthalic acid from p-xylene through oxidation or a catalyst for preparing trimellitic anhydride from trimellitic anhydride.