RU2698030C1 - Method of producing a silver suspension - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to a method of producing a suspension of silver used in production of aseptic agents and textile products. Method includes the following steps: obtaining a suspension of silver oxalate with concentration of silver oxalate particles of 5–55 g/l by dispersing silver oxalate in a dispersed medium at a temperature of -5 to 0 °C, containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in ratio of 1:1, wherein the content of the stabilizer in the dispersion medium is 1 wt%; obtaining a suspension containing silver nanoparticles and a dispersion medium containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in ratio of 1:1, wherein the content of the stabilizer in the dispersion medium is 1 wt%, and concentration of silver nanoparticles of 5–50 g/l, by adding to obtained suspension of silver oxalate solution of diethylamine in ethyl alcohol, containing 80 wt% of diethylamine and subsequent precipitation with formic acid.

EFFECT: increase in suspension stability time at which no precipitate containing silver particles precipitates in it, and increased time of increasing silver particles size.

1 cl, 4 ex

Description

FIELD OF TECHNOLOGY

The invention relates to a method for producing a suspension of silver used in the production of aseptic agents and textile products.

BACKGROUND

A known method of obtaining a suspension of silver, disclosed in US 3277002 A, publ. 10/04/1966. A method of obtaining a suspension of silver includes mixing silver alkoxide and / or a solution of silver carbonate in alcohol, hydrolysis of silver alkoxide and the removal of volatile substances.

The disadvantage of this method is the low stability of the resulting suspension of silver.

In addition, there is a known method for producing silver dispersion disclosed in the article “Facile synthesis of high silver content MOD ink by using silver oxalate precursor for inkjet printing applications” Yue Dong, Xiaodong Li, Shaohong Liu, Qi Zhua, Ji-Guang Li, Xudong Sun Thin Solid Films 589 (2015) 381–387 (prototype) obtained from a mixture of silver oxalate, ethylamine, ethylene glycol and ethyl alcohol

The disadvantages of the above disclosed method is that the resulting silver suspension has low stability, since after receiving the silver suspension the precipitate of silver particles precipitates rather quickly and the particle size increases to 100-500 nm.

SUMMARY OF THE INVENTION

The objective of the claimed invention is to develop a stable dispersion of silver.

The technical result of the invention is to increase the stability time of the suspension, in which it does not precipitate sediment containing silver particles, and increase the time to increase the size of silver particles.

The specified technical result is achieved due to the fact that the method of obtaining a suspension of silver nanoparticles includes the following steps:

- obtaining a suspension of silver oxalate with a concentration of 5-55 g / l, by dispersing the previously obtained and dried silver oxalate in a dispersion medium at a temperature of from -5 to 0 ° C, containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1 : 1, while the content of the stabilizer in the dispersion medium is 1 wt. %;

- obtaining a suspension containing silver nanoparticles and a dispersion medium containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1, while the stabilizer content in the dispersion medium is 1 wt. %, with a concentration of silver particles of 5-50 g / l, by introducing into the resulting suspension of silver oxalate a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine, and subsequent precipitation with formic acid.

As a stabilizer, a solution of a structured polymer poly (1-carbamoylethylene) is used, with the number of monomer units n = 30000-50000 in neopentyl glycol diacrylate. The concentration of the polymer in neopentyl glycol diacrylate in the range from 50 to 70 wt.%. Or, a solution of methyl ammonium salt of a copolymer of isobutylene and carboxymethyl cellulose in methoxypropyl acetate is used. The concentration of the copolymer in methoxypropyl acetate in the range from 50 to 70 wt.%.

DETAILED DESCRIPTION OF THE INVENTION

A method of obtaining a suspension of silver nanoparticles includes the following steps:

- obtaining a suspension of silver oxalate with a concentration of 5-55 g / l, by dispersing silver oxalate with a particle size of 10-50 microns in a dispersion medium at a temperature of from -5 to 0 ° C, containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1, while the content of the stabilizer in the dispersion medium is 1 wt. %;

- obtaining a suspension containing silver nanoparticles and a dispersion medium containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1, while the stabilizer content in the dispersion medium is 1 wt. %, with a concentration of silver particles of 5-50 g / l, by introducing into the resulting suspension of silver oxalate a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine, and subsequent precipitation with formic acid.

To prepare a dispersion medium, first prepare a container, for example, a flask, which is washed with running water, then flask is washed with a solution of potassium dichromate in sulfuric acid (concentration of 160-180 g of potassium dichromate per 1 liter of sulfuric acid), after which the flask is washed with distilled water to remove the residual potassium dichromate solution, and then carry out the final washing of the flask with acetone. Then, a solvent is prepared in the flask, for this purpose ethylene glycol and ethyl alcohol are mixed at a ratio of 1: 1, and the flask is placed on a tile and the solvent is drained for 30 minutes at a temperature of 150 ° C to evaporate water from it, while a trap is installed over the flask with phosphorus oxide. During the drying process, temperature control is carried out so that the solvent does not boil, but only warms up with the implementation of the evaporation of water from it. Then, 1 wt. % stabilizer and with stirring receive a dispersion medium.

Example 1

To obtain a suspension of nanosilver particles with a concentration of silver particles of 5 g / l, a solution of sodium oxalate is first prepared, for this 3.1 g of sodium oxalate powder and 100 ml of water are mixed. To accelerate the dissolution of sodium oxalate, the solution is heated to 80 ° C. A silver solution is prepared by dissolving 7.9 g of silver nitrate in 100 g of distilled water. The resulting clear solutions are mixed, resulting in a white precipitate of silver oxalate. The precipitate is filtered off either on filter paper or on a crystalline filter. The precipitate must be thoroughly washed with sodium nitrate. The mass of the obtained silver oxalate precipitate is 7.04 g. The obtained and dried silver oxalate precipitate is introduced into the stabilizer mixture — a solution of poly (1-carbamoylethylene), with n with the number of monomer units n = 30000-50000 in neopentyl glycol diacrylate, with a polymer concentration of 50 wt. % and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1 (49.5 wt.% ethylene glycol and 49.5 wt.% ethyl alcohol), while the content of the stabilizer in the dispersion medium is 1 wt. %, and carry out dispersion at a temperature of -5 ° C.

Then, 5 ml of a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine, resulting in a complex compound - silver diammonium hydroxide.

Then, the resulting complex compound is precipitated by adding 5 ml of formic acid and obtaining a suspension of nanosilver particles with a concentration of silver particles of 5 g / l and a size of 25 nm.

Within three weeks, subject to storage conditions, the particle size of the nanosilver in the suspension increases to 70 nm, which suggests that the resulting suspension of nanosilver particles has a high stability time, compared with the prototype.

Example 2

Example 2 is similar to example 1 except that a suspension of nanosilver particles with a concentration of silver particles of 10 g / l and a particle size of 30 nm is obtained. To do this, mix 6.2 g of sodium oxalate powder and 200 ml of water. To accelerate the dissolution of sodium oxalate, the solution is heated to 80 ° C. A silver solution is prepared by dissolving 15.8 g of silver nitrate in 150 g of distilled water. The resulting clear solutions are mixed, resulting in a white precipitate of silver oxalate. The precipitate is filtered off either on filter paper or on a crystalline filter. The precipitate must be thoroughly washed with sodium nitrate. The mass of the obtained precipitate of silver oxalate is 14.07 g. The obtained and dried precipitate of silver oxalate is introduced into the stabilizer mixture — a solution of poly (1-carbamoylethylene), with the number of monomer units n = 30000-50000 in neopentyl glycol diacrylate, with a polymer concentration of 60 wt. % and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1 (49.5 wt.% ethylene glycol and 49.5 wt.% ethyl alcohol), while the content of the stabilizer in the dispersion medium is 1 wt. %, and carry out dispersion at a temperature of -5 ° C.

Then in the resulting suspension of silver oxalate add 10 ml of a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine and 8 ml of formic acid.

Within three weeks, subject to storage conditions, the size of the nanosilver particles in the suspension increase to 70 nm, which indicates that the resulting suspension of nanosilver particles has a high stability time, compared with the prototype.

Example 3

Example 3 is similar to example 1 except that a suspension of nanosilver particles with a silver particle concentration of 25 g / l and a particle size of 40 nm is obtained. To do this, mix 15.5 g of sodium oxalate powder and 400 ml of water. To accelerate the dissolution of sodium oxalate, the solution is heated to 80 ° C. A silver solution is prepared by dissolving 39.5 g of silver nitrate in 300 g of distilled water. The resulting clear solutions are mixed, resulting in a white precipitate of silver oxalate. The precipitate is filtered off either on filter paper or on a crystalline filter. The precipitate must be thoroughly washed with sodium nitrate. The mass of the obtained silver oxalate precipitate is 35.175 g. The obtained and dried silver oxalate precipitate is introduced into the stabilizer mixture — a solution of poly (1-carbamoylethylene), with the number of monomer units n = 30000-50000 in neopentyl glycol diacrylate, with a polymer concentration of 70 wt. % and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1 (49.5 wt.% ethylene glycol and 49.5 wt.% ethyl alcohol), while the content of the stabilizer in the dispersion medium is 1 wt. %, and carry out dispersion at a temperature of -5 ° C.

Then in the resulting suspension of silver oxalate add 20 ml of a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine and 20 ml of formic acid.

Within three weeks, subject to storage conditions, the particle size of the nanosilver in the suspension increases to 70 nm, which suggests that the resulting suspension of nanosilver particles has a high stability time, compared with the prototype.

Example 4

Example 4 is similar to example 1 except that a suspension of nanosilver particles with a concentration of silver particles of 50 g / l and a particle size of 40 nm is obtained. To do this, mix 31 g of powder of sodium oxalate and 700 ml of water. To accelerate the dissolution of sodium oxalate, the solution is heated to 80 ° C. A silver solution is prepared by dissolving 80 g of silver nitrate in 500 g of distilled water. The resulting clear solutions are mixed, resulting in a white precipitate of silver oxalate. The precipitate is filtered off either on filter paper or on a crystalline filter. The precipitate must be thoroughly washed with sodium nitrate. The mass of the obtained precipitate of silver oxalate is 70.25 g. The obtained and dried precipitate of silver oxalate is introduced into a stabilizer mixture — a methyl ammonium salt of a copolymer of isobutylene and carboxymethyl cellulose and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a 1: 1 ratio (49.5 wt.% Ethylene glycol and 49.5 wt.% Ethyl alcohol), while the stabilizer content in the dispersion medium is 1 wt. %, and carry out dispersion at a temperature of -5 ° C.

Then in the resulting suspension of silver oxalate add 40 ml of a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine and 40 ml of formic acid.

Within three weeks, subject to storage conditions, the particle size of the nanosilver in the suspension increases to 70 nm, which suggests that the resulting suspension of nanosilver particles has a high stability time, compared with the prototype.

The invention has been disclosed above with reference to a specific embodiment. Other specialists may be obvious to other embodiments of the invention, without changing its essence, as it is disclosed in the present description. Accordingly, the invention should be considered limited in scope only below by the following claims.

Claims (4)

1. A method of obtaining a suspension of silver nanoparticles, comprising the following steps: obtaining a suspension of silver oxalate with a concentration of particles of silver oxalate 5-55 g / l by dispersing silver oxalate in a dispersion medium at a temperature of from -5 to 0 ° C, containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1, the content of the stabilizer in the dispersion medium is 1 wt. % and obtaining a suspension of silver nanoparticles in a dispersion medium containing a mixture of a stabilizer and an anhydrous solvent containing ethylene glycol and ethyl alcohol in a ratio of 1: 1, while the stabilizer content in the dispersion medium is 1 wt. %, with a concentration of silver nanoparticles of 5-50 g / l, by introducing into the resulting suspension of silver oxalate a solution of diethylamine in ethyl alcohol containing 80 wt. % diethylamine, and subsequent precipitation with formic acid. 2. The method according to p. 1, characterized in that the stabilizer is a solution of poly (1-carbamoylethylene) with the number of monomer units n = 30000-50000 in neopentyl glycol diacrylate or a 2-methyl-ammonium salt of isobutylene-carboxymethyl cellulose copolymer in methoxypropyl acetate.