Preparation method of high-purity alkyl silver sulfonate

Abstract

The invention relates to a preparation method of high-purity silver alkyl sulfonate, which comprises the following steps of: (1) preparing a silver salt solution, namely adding oxidizing acid into a reaction container, then adding water, stirring, preparing into an acid solution, heating to 28-50 DEG C, keeping constant temperature, slowly adding high-purity silver powder or silver scraps into the acid solution, stirring and reacting, and preparing to obtain the silver salt solution; (2) preparing Ag2CO3: dissolving carbonate in distilled water to form a carbonate solution, introducing the carbonate solution into the silver salt solution in a dark environment to obtain an Ag2CO3 precipitate, and washing and filtering for a plurality of times to obtain silver carbonate powder; and (3) preparing the alkyl silver sulfonate: in a dark environment, adding distilled water into alkyl sulfonic acid to prepare an alkyl sulfonic acid solution, then heating to 40-85 DEG C, keeping the constant temperature, adding the silver carbonate powder into the alkyl sulfonic acid solution, stirring and reacting to obtain an alkyl silver sulfonate solution, and then carrying out reduced pressure distillation to prepare the alkyl silver sulfonate with the purity of more than 99.9%. The method is high in reaction speed and low in energy consumption, and the prepared alkyl silver sulfonate product is high in purity, high in yield, short in production period and low in production cost.

Description

Technical Field

[0001] The invention belongs to the technical field of alkyl sulfonate preparation, and particularly relates to a method for preparing high-purity silver alkyl sulfonate. Background Art

[0002] Alkyl sulfonate silver has the advantages of safety, non-toxicity, excellent electrical conductivity, good solderability, etc., and is widely used in electroplating (such as the cyanide-free silver plating electroplating solution and electroplating method disclosed in CN106567109A), surface treatment such as chemical plating, preparation of nano antibacterial silver materials, and catalysts in organic synthesis. Compared with traditional silver plating processes (such as cyanide silver plating processes), alkyl sulfonic acid silver plating has the advantages of good environmental protection, high conductivity, high current density range, high bonding strength, and low toxicity of electroplating solutions. It has the trend of gradually replacing traditional silver plating processes, and the demand for alkyl sulfonate silver will also increase.

[0003] The traditional method for preparing silver alkyl sulfonate is to use electrolysis technology to place silver plates at both ends of the electrolysis device, separated by an ion exchange membrane in the middle, add alkyl sulfonic acid solution to the electrolysis device, electrolyze to produce silver alkyl sulfonate solution at a certain current density, and prepare silver alkyl sulfonate powder by filtering and concentration. However, when it comes to industrial applications, companies need to store a large number of silver ingots, and the price of precious metal silver fluctuates greatly with the market environment, which brings a greater risk of financial loss to the company. At the same time, the factory's electricity demand and other needs increase accordingly, which is easy to cause asset loss, and there are problems such as high production costs, long production cycles, and energy waste. Some other technologies, such as the preparation of silver methyl sulfonate by reacting metallic silver or silver oxide with methanesulfonic acid, have slow reaction speeds and high reaction temperature requirements (>100°C), and are prone to produce black substances, low silver yields, and easy product deterioration. Summary of the invention

[0004] In view of the above problems, the present invention aims to provide a method for preparing high-purity alkyl silver sulfonate which is simple, convenient, has low production cost, short cycle and high yield, and strives to solve the problems of the need to store a large amount of silver ingots for the industrial electrolytic preparation of alkyl silver sulfonate, the waste of energy, low silver yield, easy generation of black matter, high production cost and low safety caused by the high temperature (>100°C) dissolution of silver oxide to prepare alkyl silver sulfonate through a chemical double decomposition reaction.

[0005] The technical solution adopted by the present invention is as follows: A method for preparing high-purity silver alkyl sulfonate comprises the following steps: (1) Preparing a silver salt solution: adding an oxidizing acid to a reaction vessel, then adding distilled water, stirring to prepare an acid solution with a mass concentration of 15% to 35%, heating to 28 to 50°C and maintaining a constant temperature, then slowly adding high-purity silver powder or silver flakes to the acid solution, stirring and reacting within the temperature range for a certain period of time, and preparing a silver salt solution after Ag and the oxidizing acid react completely, and cooling the silver salt solution for standby use; (2) preparing Ag2CO3: dissolving carbonate in distilled water to form a carbonate solution with a mass concentration of 8-14%, introducing the carbonate solution into the silver salt solution obtained in step (1) by using a flow guide device under a light-proof environment, reacting to obtain Ag2CO3 precipitate, washing and filtering the precipitate to obtain white silver carbonate powder; (3) Preparation of silver alkyl sulfonate: Under a light-proof environment, weigh alkyl sulfonic acid, add distilled water to prepare an alkyl sulfonic acid solution with a mass concentration of 25% to 35%, then heat to 40 to 85° C. and maintain a constant temperature, slowly add the silver carbonate powder prepared in step (2) to the alkyl sulfonic acid solution and stir to react to obtain an alkyl sulfonate silver solution, and then perform reduced pressure distillation to prepare an alkyl sulfonate silver with a purity greater than 99.9%.

[0006] Furthermore, the oxidizing acid in step (1) is nitric acid.

[0007] Furthermore, the stirring reaction time after adding the high-purity silver powder or silver flakes into the acid solution is 45 min.

[0008] Furthermore, the purity of the high-purity silver powder or silver flakes in step (1) is ≥99.9%.

[0009] Furthermore, the carbonate in step (2) is one or more of Na2CO3, K2CO3, and Mg2CO3; and the mass ratio of the silver salt solution to the carbonate solution is 1:1 to 1:1.2.

[0010] Furthermore, the precipitate is washed with distilled water for 3 to 5 times.

[0011] Furthermore, the alkyl sulfonic acid in step (3) is one or more of methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, butyl sulfonic acid, and octyl sulfonic acid.

[0012] The present invention utilizes high-purity Ag to react with a nitric acid solution, and then double decomposes with a carbonate solution to prepare a silver carbonate solution, obtains a high-purity silver carbonate powder after washing and filtering, and then dissolves the powder in an alkyl sulfonic acid solution at a relatively low temperature (40-85°C) to prepare a high-purity alkyl sulfonate silver solution. Compared with the existing preparation technology, the preparation process of the present invention is simple, convenient, high in yield, low in energy consumption, short in preparation cycle, and high in quality of the prepared product, avoiding the generation of black matter, and not requiring the production enterprise to store a large amount of silver ingots, which can greatly reduce the production cost. DETAILED DESCRIPTION

[0013] The present invention is further described below with examples. It should be understood by those skilled in the art that the examples are only partial examples of the present invention, not all examples, and are not intended to limit the scope of protection of the present invention. Example 1

[0014] A method for preparing high-purity silver alkyl sulfonate. 114.512 g of a nitric acid solution with a mass fraction of 68% is weighed and added to a four-necked flask, and then distilled water is added, and the mixture is fully mixed to prepare a nitric acid solution with a mass concentration of 15%. Stirring is started, and the temperature is controlled within the range of 40-50°C. Then, 100 g of silver powder with a purity of >99.9% is prepared and slowly added to the four-necked flask, and stirring is started to allow the silver to fully react with the nitric acid solution. The reaction lasts for about 45 minutes, and stirring is stopped after the reaction of the silver powder and the nitric acid in the flask is observed to be complete. The reaction solution is allowed to stand and cool for use. Weigh 54.03 g of sodium carbonate, add distilled water to prepare a sodium carbonate solution with a mass concentration of 8%, use an automatic diversion device, at room temperature and in a light-proof environment, according to the mass ratio of silver salt solution to carbonate solution of 1:1.1, control the flow rate and slowly add the sodium carbonate solution into the four-necked flask, and start the stirring device of the four-necked flask at the same time. After all the sodium carbonate solution is added to the reaction flask, continue to stir and react for 1 h to convert all the silver nitrate in the system into silver carbonate white precipitate. In a light-proof environment, the white precipitate is accurately filtered and washed with distilled water 3 times to remove impurities in the precipitate to obtain white silver carbonate powder (purity ≥99.932%) for standby use. Weigh 297 g of methanesulfonic acid into a reaction device, add distilled water to prepare a methanesulfonic acid solution with a mass concentration of 30%, turn on the stirring and heating device, and when the temperature rises to 45-65°C, slowly add the prepared silver carbonate powder into the reaction device, and react fully for 2 hours under continuous stirring and 50-80°C. After the silver carbonate and methanesulfonic acid have completely reacted, continue to reduce pressure and concentrate at 40-75°C to prepare high-purity silver methanesulfonate.

[0015] The reaction equation of silver powder and nitric acid is as follows: 3Ag + 4HNO3 → 3AgNO3 + 2H2O + NO↑ The reaction equation of silver nitrate and sodium carbonate is as follows: 2AgNO3 + Na2CO3 → Ag2CO3 + 2NaNO3 The reaction equation of silver carbonate and methanesulfonic acid is as follows: Ag2CO3+2CH3SO3H→ 2CH3SO3Ag+CO2↑+H2O. Example 2

[0016] A method for preparing high-purity silver alkyl sulfonate. Weigh 230 g of a nitric acid solution with a mass fraction of 68% and add it to a reaction flask, then add distilled water, mix it thoroughly to prepare a nitric acid solution with a mass concentration of 20%, start stirring, control the temperature within the range of 35-50°C, then prepare about 200 g of silver powder (purity> 99.95%), slowly add it to a four-necked flask, start stirring to allow the silver to fully react with the dilute nitric acid solution for 45 minutes, stop stirring after observing that the reaction of the silver powder and nitric acid in the flask is complete, and let the reaction solution stand and cool for use. Weigh 153.52 g of potassium carbonate, add distilled water to prepare a potassium carbonate solution with a mass concentration of 12%, use an automatic diversion device, at room temperature and in a light-proof environment, control the flow rate to slowly add potassium carbonate into the reaction flask at a mass ratio of silver salt solution to carbonate solution of 1:1.2, and start the stirring device of the reaction flask at the same time. After all the potassium carbonate solution is added to the reaction flask, continue to stir and react for 1 h to convert all the silver nitrate in the system into silver carbonate, which precipitates out in the form of a white precipitate. In a light-proof environment, the white precipitate is precisely filtered and washed with distilled water 4 times to remove impurities in the precipitate to obtain white potassium carbonate powder (purity ≥99.957%) for standby use. Weigh 510 g of propyl sulfonic acid into a reaction device, add distilled water to prepare a propyl sulfonic acid solution with a mass concentration of 35%, turn on the stirring and heating device, and when the temperature rises to 45-65°C, slowly add the prepared silver carbonate powder into the reaction device, and fully react for 2 hours under continuous stirring and 45-65°C. After the silver carbonate and propyl sulfonic acid have completely reacted, continue to reduce pressure and concentrate at 40-65°C to prepare high-purity silver propyl sulfonate. Example 3

[0017] A method for preparing high-purity silver alkyl sulfonate. 344 g of a nitric acid solution with a mass concentration of 68% is weighed and added to a four-necked flask, and then distilled water is added to mix it thoroughly and dilute it into a dilute nitric acid solution of about 30%, and stirring is started, and the temperature is controlled in the range of 40-50°C, and then about 300 g of silver powder (purity> 99.99%) is prepared, and it is slowly added to the four-necked flask, and stirring is started to allow the silver and nitric acid solution to fully react for 45 minutes, and the stirring is stopped after the reaction of the silver powder and nitric acid in the flask is observed to be complete, and the reaction solution is allowed to stand and cool for use. Weigh another 148 g of sodium carbonate, add 905 g of distilled water and stir to dissolve it to prepare a 14% sodium carbonate solution. Use an automatic diversion device to control the flow rate to slowly add potassium carbonate into the reaction flask. At the same time, start the stirring device of the reaction flask. After all the sodium carbonate solution is added to the reaction flask, continue to stir and react at room temperature for 1 h to convert all the silver nitrate in the system into silver carbonate, which precipitates out in the form of a white precipitate. Filter the white precipitate in a light-proof environment and wash it with distilled water 5 times to remove impurities in the precipitate to obtain white potassium carbonate powder (purity ≥99.986%) for standby use. 1226 g of ethylsulfonic acid was weighed into a reaction device, and distilled water was added to prepare an ethylsulfonic acid solution with a mass concentration of 25%. The stirring and heating device was turned on. When the temperature was raised to 45-65°C, the prepared silver carbonate powder was slowly added to the reaction device. Under continuous stirring and maintaining the temperature at 45-65°C, the reaction was fully carried out for 2 hours. The silver carbonate and ethylsulfonic acid were completely reacted. The reduced pressure concentration was continued at 40-65°C to prepare high-purity silver ethylsulfonate. The technical indicators of the high-purity silver alkyl sulfonate obtained in each embodiment are shown in the following table:

[0018] The alkyl sulfonic acid used in the preparation of the alkyl sulfonic acid solution of the present invention may be butyl sulfonic acid, octyl sulfonic acid, or a combination of any two or three of methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, butyl sulfonic acid, and octyl sulfonic acid, in addition to the methyl sulfonic acid, ethyl sulfonic acid, and propyl sulfonic acid mentioned in the embodiments.

[0019] The raw materials used in the method of the present invention can all be commercially available.

[0020] Unless otherwise specified, all percentages described in the present invention are by mass percentages.

Claims

1. A method for preparing high-purity silver alkyl sulfonate, characterized in that: The following steps are involved: (1) Preparing a silver salt solution: adding an oxidizing acid to a reaction vessel, then adding distilled water, stirring to prepare an acid solution with a mass concentration of 15% to 35%, heating to 28 to 50°C and maintaining a constant temperature, then slowly adding high-purity silver powder or silver flakes to the acid solution, stirring and reacting within the temperature range for a certain period of time, and preparing a silver salt solution after Ag and the oxidizing acid react completely, and cooling the silver salt solution for standby use; (2) preparing Ag2CO3: dissolving carbonate in distilled water to form a carbonate solution with a mass concentration of 8-14%, introducing the carbonate solution into the silver salt solution obtained in step (1) by using a flow guide device under a light-proof environment, reacting to obtain Ag2CO3 precipitate, washing and filtering the precipitate to obtain white silver carbonate powder; (3) Preparation of silver alkyl sulfonate: Under a light-proof environment, weigh alkyl sulfonic acid, add distilled water to prepare an alkyl sulfonic acid solution with a mass concentration of 25% to 35%, then heat to 40 to 85° C. and maintain a constant temperature, slowly add the silver carbonate powder prepared in step (2) to the alkyl sulfonic acid solution and stir to react to obtain an alkyl sulfonate silver solution, and then perform reduced pressure distillation to prepare an alkyl sulfonate silver with a purity greater than 99.9%.

2. The method for preparing high-purity silver alkyl sulfonate according to claim 1, characterized in that: The oxidizing acid in step (1) is nitric acid.

3. A method for preparing high-purity silver alkyl sulfonate according to claim 1 or 2, characterized in that: The stirring reaction time after adding the high-purity silver powder or silver flakes to the acid solution in step (1) is at least 45 minutes.

4. A method for preparing high-purity silver alkyl sulfonate according to claim 1 or 2, characterized in that: The purity of the high-purity silver powder or silver flakes in step (1) is ≥99.9%.

5. The method for preparing high-purity silver alkyl sulfonate according to claim 1, characterized in that: In step (2), the carbonate is one or more of Na2CO3, K2CO3, and Mg2CO3; the mass ratio of the silver salt solution to the carbonate solution is 1:1 to 1:1.

2.

6. The method for preparing high-purity silver alkyl sulfonate according to claim 1 or 5, characterized in that: The precipitate is washed with distilled water for 3 to 5 times.

7. The method for preparing high purity silver alkyl sulfonate according to claim 1, characterized in that: The alkyl sulfonic acid in step (3) is one or more of methyl sulfonic acid, ethyl sulfonic acid, propyl sulfonic acid, butyl sulfonic acid and octyl sulfonic acid.

Images