阅读说明：本技术 一种半胱氨亚金酸固体的制备方法 (Preparation method of cysteine aurous acid solid ) 是由 杨防祖 金磊 杨家强 詹东平 吴德印 田中群 于 2020-03-06 设计创作，主要内容包括：本发明公开了一种半胱氨亚金酸固体的制备方法,其制备原料包括三价金物料、还原剂和半胱氨酸。该原料中的三价金物料也可用单质金与王水制备,该原料中的金源也可直接使用亚硫酸金钠或亚硫酸金钾。该还原剂为具有弱还原性的有机或无机化合物,能够选择性还原三价金物料为一价金化合物,以避免生成单质金。在本发明提供的一种半胱氨亚金酸固体的制备方法中,半胱氨酸能够稳定地配位一价金离子。本发明制备方法简单可控,重复性好,耗时短。(The invention discloses a preparation method of cysteine aurous acid solid, and the preparation raw materials comprise trivalent gold material, reducing agent and cysteine. The trivalent gold material in the raw material can also be prepared from simple substance gold and aqua regia, and the gold source in the raw material can also be directly prepared from sodium gold sulfite or potassium gold sulfite. The reducing agent is an organic or inorganic compound with weak reducibility, and can selectively reduce trivalent gold materials into monovalent gold compounds so as to avoid generating simple substance gold. In the preparation method of the cysteine aurous acid solid, cysteine can stably coordinate monovalent gold ions. The preparation method is simple and controllable, good in repeatability and short in time consumption.)

1. A preparation method of cysteine aurous acid solid is characterized by comprising the following steps: the method comprises the following steps:

(1) dissolving a trivalent gold material in deionized water to obtain a trivalent gold solution, dissolving a reducing agent in deionized water to obtain a reducing agent solution, slowly adding the trivalent gold solution into the reducing agent solution, and adjusting the pH to 8.5-12.0 by using an alkaline pH regulator solution to obtain a monovalent gold solution; or dissolving sodium gold sulfite or potassium gold sulfite in deionized water to obtain monovalent gold solution.

(2) Adding the solid or the aqueous solution of cysteine into the monovalent gold solution, fully stirring, adjusting the pH to 8.5-12.0 by using an alkaline pH regulator solution, and then fixing the volume to obtain a crude product solution of cysteine aurous salt;

(3) adjusting the pH value of the crude product solution to 0.5-4.5 by using an acidic pH regulator solution, and obtaining a solid precipitate of cysteine after reduced pressure filtration or centrifugal filtration;

(4) fully washing the solid precipitate with deionized water, drying at 50-70 deg.C for 6-12h to obtain cysteine aurous acid solid, and adding alkaline pH regulator solution into the cysteine aurous acid solid to obtain cysteine aurous acid salt solution.

2. The method according to claim 1, wherein the concentration of gold in the green solution is 0.04-110 g/L.

3. The method of claim 1, wherein: in the step (1), the trivalent gold material includes a product obtained by dissolving simple substance gold in aqua regia and removing residual nitric acid, tetrachloroauric acid, an alkali metal salt of tetrachloroauric acid, or an ammonium salt of tetrachloroauric acid.

4. The method of claim 1, wherein: the reducing agent in the step (1) can not directly reduce the trivalent gold material into simple substance gold.

5. The process according to claim 4, wherein the reducing agent comprises at least one member selected from the group consisting of pyrosulfurous acid, alkali metal salts of pyrosulfurous acid, ammonium salts of pyrosulfurous acid, thiosulfuric acid, alkali metal salts of thiosulfuric acid, ammonium salts of thiosulfuric acid, sulfurous acid, alkali metal salts of sulfurous acid, ammonium salts of sulfurous acid, hypophosphorous acid, alkali metal salts of hypophosphorous acid, ammonium salts of hypophosphorous acid, phenols, alkali metal phenolates and ammonium phenolates, and the concentration of the reducing agent in the solution of the crude product is from 0.005 to 100 g/L.

6. The process according to claim 1, wherein the basic pH adjusting agent in the step (1) is an alkali metal hydroxide or aqueous ammonia, and the concentration of the basic pH adjusting agent in the solution of the crude product is 0.1 to 200 g/L.

7. The method of claim 1, wherein: the acidic pH regulator in the step (3) is sulfuric acid, hydrochloric acid or nitric acid.

8. The method of claim 7, wherein: the volume concentration of the acidic pH regulator solution is 5-40%.

9. The method according to claim 1, wherein the cysteine is L-cysteine or D-cysteine, and the concentration of the aqueous solution of cysteine is 0.05 to 280 g/L.

10. The method of claim 1, wherein: the mol ratio of the reducing agent, the cysteine and the trivalent gold ions in the trivalent gold material is 0.25-2: 2-4: 1.

Technical Field

The invention belongs to the field of compound preparation, and particularly relates to a preparation method of cysteine aurous acid solid.

Background

Compared with a trivalent gold material, the monovalent gold compound has more advantages in the fields of fluorescent materials, drug treatment, catalysis, cyanide-free electroplating and the like, Au (I) -mercaptide compounds can be used for clinically treating tuberculosis in the field of drug treatment, Au (I) -phosphine compounds can be used for treating rheumatoid arthritis, the cure rate of the compounds reaches 70%, in the field of catalysis, 6s orbital contraction, L UMO orbital energy reduction and electronegativity enhancement of monovalent gold ions are realized, 5d orbital expansion, electron repulsion force reduction and HOMO orbital level increase are realized, so that the monovalent gold ions can easily activate an n-system such as alkyne and alkene, in the field of cyanide-free electroplating, reduction of the monovalent gold ions only needs to obtain one electron, the current utilization efficiency is high, and a plating layer has no gold intermediate inclusion.

To date, monovalent gold compounds have been obtained primarily by selective reduction of trivalent gold materials. CN105671515A discloses a simple preparation method of a monovalent gold nanoparticle/three-dimensional graphene/foamed nickel composite structure. The method takes chloroauric acid as a gold source and sodium borohydride as a reducing agent to obtain a monovalent gold compound. CN 108441901A discloses a gold electroplating solution of cyanide-free organic solvent, in a non-aqueous solvent, chloroauric acid is used as a gold source, and sodium borohydride, ascorbic acid, oxalic acid or thiourea is used as a reducing agent to obtain a monovalent gold electroplating solution. However, the reducing agents such as sodium borohydride and ascorbic acid have strong reducing power, so that the stability of monovalent gold ions cannot be guaranteed, and the monovalent gold ions are easily reduced into simple gold continuously.

CN 103253697a discloses a method for preparing monovalent gold compounds, which uses soluble compounds containing mercapto group as reducing agents to selectively reduce trivalent gold ions. But the sulfhydryl soluble compound used by the method is oxidized into a dithio compound and can also be coordinated with monovalent gold ions, and the final product is a mixture; in addition, the process needs high-temperature heating, evaporation concentration and even decompression reflux for 10 hours, and the operation steps are complicated. CN 103288121A discloses a method for synthesizing a monovalent gold complex by inverse disproportionation reaction, which takes trivalent gold material and simple substance gold as raw materials to synthesize a monovalent gold compound by inverse disproportionation reaction, and the method also needs high-temperature heating and reflux maintaining, and the time consumption can reach 160h at most. In addition, no matter the univalent gold compound generated by selectively reducing the trivalent gold ions or the univalent gold compound generated by inverse disproportionation, the univalent gold ions are easy to generate disproportionation reaction at high temperature to generate simple gold and trivalent gold materials.

Cysteine has nitrogen, oxygen and sulfur atoms providing a lone electron pair of coordination, can be stably coordinated with monovalent gold ions, and has a coordination number of 2. Through the calculation of a density functional theory, the specific coordination atom is a sulfur atom, and the formed complex is very stable.

In a word, although the preparation methods of the univalent gold compounds at the present stage have respective characteristics, the preparation methods also have the obvious defects of poor stability of univalent gold ions, complex operation and the like. Therefore, the preparation method of the aurous compound, which has the advantages of good stability, simplicity, controllability, good repeatability and short time consumption, has important practical significance.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a preparation method of cysteine aurous acid solid.

The technical scheme of the invention is as follows:

a preparation method of cysteine aurous acid solid comprises the following steps:

(1) dissolving a trivalent gold material in deionized water to obtain a trivalent gold solution, dissolving a reducing agent in deionized water to obtain a reducing agent solution, slowly adding the trivalent gold solution into the reducing agent solution, and adjusting the pH to 8.5-12.0 by using an alkaline pH regulator solution to obtain a monovalent gold solution; or dissolving sodium gold sulfite or potassium gold sulfite in deionized water to obtain monovalent gold solution.

(2) Adding the solid or the water solution of cysteine into the monovalent gold solution, fully stirring, adjusting the pH to 8.5-12.0 by using an alkaline pH regulator solution, and then fixing the volume to obtain a cysteine aurous salt crude product solution with the concentration of 0.1-200 g/L;

(3) adjusting the pH value of the crude product solution to 0.5-4.5 by using an acidic pH regulator solution, and obtaining a solid precipitate of cysteine after reduced pressure filtration or centrifugal filtration;

(4) fully washing the solid precipitate with deionized water, drying at 50-70 deg.C for 6-12h to obtain cysteine aurous acid solid, and adding alkaline pH regulator solution into the cysteine aurous acid solid to obtain cysteine aurous acid salt solution.

In a preferred embodiment of the invention, the concentration of gold elements in the crude solution is between 0.04 and 110 g/L.

In a preferred embodiment of the invention, the trivalent gold material comprises the product of dissolving elemental gold in aqua regia and removing the remaining nitric acid, tetrachloroauric acid, an alkali metal salt of tetrachloroauric acid, or an ammonium salt of tetrachloroauric acid.

In a preferred embodiment of the present invention, the reducing agent in step (1) is not capable of directly reducing the above-mentioned trivalent gold material to elemental gold.

Further preferably, the reducing agent includes at least one of pyrosulfurous acid, an alkali metal salt of pyrosulfurous acid, an ammonium salt of pyrosulfurous acid, thiosulfuric acid, an alkali metal salt of thiosulfuric acid, an ammonium salt of thiosulfuric acid, sulfurous acid, an alkali metal salt of sulfurous acid, ammonium salt of sulfurous acid, hypophosphorous acid, an alkali metal salt of hypophosphorous acid, an ammonium salt of hypophosphorous acid, phenols, alkali metal phenolates, and ammonium phenolates, and the concentration of the reducing agent in the crude product solution is 0.005 to 100 g/L.

In a preferred embodiment of the present invention, the basic pH adjusting agent in the step (1) is an alkali metal hydroxide or aqueous ammonia, and the concentration of the basic pH adjusting agent in the crude product solution is 0.1 to 200 g/L.

In a preferred embodiment of the present invention, the acidic pH adjusting agent in the step (3) is sulfuric acid, hydrochloric acid or nitric acid.

Further preferably, the volume concentration of the acidic pH regulator solution is 5-40%.

In a preferred embodiment of the invention, the cysteine is L-cysteine or D-cysteine, and the concentration of the aqueous solution of cysteine is 0.05-280 g/L.

In a preferred embodiment of the invention, the molar ratio of the reducing agent, cysteine and trivalent gold ions in the trivalent gold material is 0.25-2: 2-4: 1.

The cysteine aurous solid or cysteine aurous salt solution prepared by the invention is stored in a sealing way at room temperature.

The appearance of the prepared cysteine aurous solid precipitate is blocky white gray, and the cysteine aurous solid precipitate can be shaped into powder after being rolled; the prepared cysteine aurous salt solution is transparent and colorless in appearance.

In the step (1), the reducing agent has weak reducibility and can selectively reduce the trivalent gold material into a monovalent gold compound; the molar concentration ratio of the reducing agent to the trivalent gold ions in the trivalent gold material is lower than 0.25: 1, and all the trivalent gold material cannot be reduced into a monovalent gold compound; the molar concentration ratio of the reducing agent to the trivalent gold ions is higher than 2: 1, and the reducing agent is remained in the solution, which can cause the monovalent gold compound to be continuously reduced into the simple gold. The content of the reducing agent is optimized to reduce the trivalent gold ions into equivalent values of monovalent gold ions.

If the pH is lower than 8.5 in the step (1), the monovalent gold compound is continuously reduced to zero-valent gold nanoparticles; if the pH is higher than 12.0, excessive hydroxide radicals will perform a coordination reaction with the trivalent gold ions in the trivalent gold material, which will make it difficult for the reducing agent to destroy the complex structure of the trivalent gold ions and the hydroxide radicals. In addition, through operations such as uniform stirring, slow addition of the trivalent gold material into a reducing agent solution and the like, trivalent gold ions in the trivalent gold material can be prevented from being directly reduced into zero-valent gold nanoparticles due to overhigh concentration of local reducing agents.

In the step (1), gold sodium sulfite or gold potassium sulfite can be directly used to prepare the monovalent gold solution. However, since commercial gold sodium sulfite or gold potassium sulfite is often a solution containing a large amount of free sulfite, the gold sodium sulfite or gold potassium sulfiteRefers to free sulfite SO₃ ^2-The concentration of (a) is 0.1-5 g/L of a gold sodium sulfite or gold potassium sulfite solution.

In the step (2), the coordination ratio of the cysteine to the monovalent gold ions in the monovalent gold solution is 2: 1. The molar concentration of the trivalent gold ions in the trivalent gold material is the molar concentration of the monovalent gold ions in the monovalent gold compound. When the molar concentration ratio of the cysteine to the trivalent gold ions is less than 2: 1, the cysteine cannot sufficiently and stably perform a coordination reaction with all the monovalent gold ions in the monovalent gold solution; when the molar concentration ratio of the cysteine to the trivalent gold ion is higher than 4: 1, the cysteine in excess will exceed its solubility range, which will result in the formation of a mixed precipitate of the cysteine and cysteine in the subsequent steps, which is difficult to separate and purify.

In the above step (3), the purpose of the reduced pressure filtration or the centrifugal filtration is to rapidly realize the solid-liquid separation.

The invention has the beneficial effects that:

1. the method is simple and controllable, good in repeatability and short in time consumption.

2. The cysteine aurous acid solid and salt solution prepared by the method has good stability and high yield, and can be used in the fields of fluorescent materials, drug therapy, catalysis, cyanide-free gold electroplating and the like.

Drawings

FIG. 1 is a photograph of a cysteine-aurous solid obtained in example 1 of the present invention.

FIG. 2 is a photograph of a cysteine-aurous salt solution obtained in example 1 of the present invention.

Detailed Description

The following examples are given for the purpose of illustration and are not intended to limit the scope of the present invention.