CN102274740A - Novel method for preparing metal cyanide nanoparticles - Google Patents

Abstract

The invention discloses a green synthesis method for preparing gold cyanide (AuCN) and other transition metal cyanide (such as AgCN, CuCN, Pt(CN) ₄ , Pd(CN) ₂ , Ru(CN) ₄ , etc.) nanoparticles method. Nano-gold (or nano-silver, nano-silver oxide, nano-copper, nano-copper oxide, nano-ruthenium, nano-platinum, nano-palladium and other transition metal nanoparticles) is loaded on a conventional porous carrier (silica, alumina, titanium oxide, carbon , porous materials such as polymers), and mixed with benzaldehyde (or benzyl alcohol, hydrogen peroxide) and acetonitrile to form a suspension system, and synthesize transition metal cyanide nanoparticles in the next step of ultraviolet light irradiation. The product is uniformly dispersed, crystallized well, and the particle size is 1-100 nanometers.

Description

A new method for preparing metal cyanide nanoparticles

technical field

The invention relates to a new preparation method of metal cyanide nanoparticles.

Background technique

Cyanide refers to the substance containing cyano group (-C≡N) in the compound molecule. According to whether the element or group connected to the cyano group is organic or inorganic, cyanide can be divided into two categories, namely organic cyanide and inorganic cyanide. The former is called nitrile, and the latter is often referred to simply as cyanide. Cyanide is an important gold leaching solvent in the gold industry, and most gold production enterprises use cyanide. Among them, the representative cyanides are Prussian blue, gold cyanide and so on.

Here we take gold cyanide as an example. The chemical formula of gold cyanide is AuCN, the molecular weight is 222.98, the specific gravity is 7.12, and the English name is Gold(I) Cyanide. It is a chain-like inorganic polymer, and it is a hexagonal lemon yellow fine crystal. It is stable in dry air, but it decomposes when heated. And free gold is unstable when exposed to light in a wet state, insoluble in water and dilute acids, but soluble in solutions such as alkali metal cyanide, potassium hydroxide or ammonia water, and also soluble in solutions of sodium thiosulfate or ammonium sulfide . Gold cyanide is widely used in chemical analysis, electroplating, electronics and other industries. In 1783, Carl Wilhelm Scheele discovered that gold can be dissolved in sodium cyanide to obtain the corresponding gold cyanide salt. This reaction was later called "Elsner Equation ", and its reaction pathway is as follows:

4 Au + 8 NaCN + O ₂ + 2 H ₂ O → 4 Na[Au(CN) ₂ ] + 4 NaOH

In order to obtain the corresponding AuCN solid precipitation, it is necessary to add acid for a second reaction:

KAu(CN) ₂ + HCl = AuCN + HCN + KCl

In the metallurgical industry, this reaction process is called the MacArthur-Forrest process. Because the obtained products (such as Na[Au(CN) ₂ ] and K[Au(CN) ₂ , etc.) are soluble in water, it is beneficial to extract high-quality gold, silver and other precious metals. However, since this reaction involves highly toxic cyanide, such as NaCN, HCN, etc., it will cause great pollution to the environment, so many countries have banned the use of such chemical reactions to extract gold ore. So far, a green and facile one-step synthetic chemistry method for the preparation of AuCN that can replace the above process has not been developed in the world.

In terms of theoretical research, many scholars have analyzed the crystal of AuCN. Since cyanides are generally highly toxic products, little consideration has been given to their use as catalysts. Recently, Oyama et al. found that Na[Au(CN) ₂ ] has a catalytic hydrogenation effect similar to that of Pt (ChemCatChem 2010, 2, 1582 – 1586), which aroused the interest of the catalytic community. However, so far, no one has publicly reported the preparation of AuCN nanoparticles and their applications in catalysis and other fields. In addition, Au cyanide can also be used in biopharmaceuticals and medicine, such as the treatment of arthritis, and even has the prospect of treating cancer and AIDS (Chem. Rev. 1999, 99, 2589−2600).

Contents of the invention

Since the MacArthur-Forrest process cannot be used to synthesize AuCN (AgCN, CuCN, Pt(CN) ₄ , Pd(CN) ₂ , Ru(CN) _{4 ,} etc.) Cyanide nanoparticles.

Concrete technical scheme of the present invention is as follows:

The present invention is a kind of new method for preparing metal cyanide nano-particles, and the preparation steps of this method are as follows:

1) Mix supported metal (or metal oxide) nanoparticles, acetonitrile, and benzaldehyde (or benzyl alcohol, hydrogen peroxide) in different molar ratios, and the relative content molar ratio is: metal (metal oxide) nanoparticles/benzene Formaldehyde (or benzyl alcohol, hydrogen peroxide) / acetonitrile = 0.1~2.0/1~10/100;

2) Place the above suspension under a 350-watt mercury lamp, stir and illuminate for 1 to 20 hours;

3) The product is centrifuged and dried to obtain loaded metal cyanide nanoparticles.

The metal or metal oxide nanoparticles in the present invention are Au, Ag, Ag ₂ O, Cu, Cu ₂ O, Ru, Pt or Pd.

The metal or metal oxide nanoparticles described in the present invention are nanoparticles with a diameter of 1 to 50 nanometers, and are loaded on a conventional porous carrier, and the porous carrier is silicon dioxide, aluminum oxide, titanium oxide, carbon or high Molecularly porous materials.

The chemical formula of the nano metal cyanide in the present invention is AuCN, AgCN, CuCN, Pt(CN) ₄ , Pd(CN) ₂ or Ru(CN) ₄ , and the particle diameter is 1-100 nanometers.

The beneficial effects of the present invention are as follows: 1) The present invention abandons the highly toxic substances widely used in the traditional metallurgical industry, such as NaCN and KCN, does not pollute the environment, and the reaction process is simple and extremely green; 2) The cyanide is prepared in the present invention In the process, green raw materials, acetonitrile and benzyl alcohol (or benzaldehyde, hydrogen peroxide) are used; 3) The present invention does not involve the generation of toxic gas, hydrocyanic acid (HCN); 4) The reaction conditions of the present invention are mild, that is, room temperature 5) The present invention can synthesize supported metal cyanide nanoparticles in one step on the porous material, and the particle size is controllable; 6) The present invention can not only use zero-valent metals as reactants, but also high-valent metal oxides As reactants, metal cyanide nanoparticles were prepared.

Description of drawings

Fig. 1 is the transmission electron micrograph of the AuCN nanoparticle gained in embodiment 1;

Fig. 2 is the XRD collection of illustrative plates of embodiment 2 gained AuCN nanoparticles;

Fig. 3 is the XPS collection of illustrative plates of embodiment 3 gained AuCN nanoparticles;

Fig. 4 is the XRD spectrum of the AgCN nanoparticles obtained in Example 4.

Detailed ways

The present invention is a kind of novel method for preparing metal cyanide nano-particles, and its specific steps are as follows:

1. First, load nano-gold (or other metal/metal oxide nanoparticles) on a porous carrier (porous materials such as silica, alumina, titanium oxide, carbon, and polymer);

2. Mix the above materials with acetonitrile and benzaldehyde (or benzyl alcohol, hydrogen peroxide), and control the metal mass to 1-500 mg; the molar weight of acetonitrile is 0.0125-0.125 moles; The concentration is 0.008-0.08 mol/liter. stir;

3. Place the above suspension under a 350-watt mercury lamp, stir and illuminate, and the illumination time is 1 to 20 hours;

4. The product is centrifuged and dried to obtain loaded nano-gold cyanide (or other metal cyanide).

The technical solutions of the present invention will be further described below through specific examples.

Example 1

First, mix 10 mg nano-gold-loaded mesoporous silica, 2 mL acetonitrile, and 100 μmol benzaldehyde, and stir; place the above suspension under a 350-watt mercury lamp, stir and illuminate, and the illumination time is 2 hours , the color of the solid gradually changed from red to green; the product was centrifuged and dried to obtain nano-gold cyanide-loaded mesoporous silica. Fig. 1 is this nano-gold cyanide TEM photo, from which it can be obtained that the product is nanoparticles, uniformly dispersed, and the particle diameter is 10-30 nanometers.

Example 2

Mix 100 mg of supported gold nanoparticles, 4 mL of acetonitrile, and 200 μmol of benzyl alcohol together and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 5 hours, and the color of the solid is determined by The red color gradually changed to green; the product was centrifuged and dried to obtain loaded nano-gold cyanide. Figure 2 is the XRD spectrum of the nano-gold cyanide, the product is pure gold cyanide, the chemical formula is AuCN.

Example 3

Mix 500 mg of supported gold nanoparticles, 5 mL of acetonitrile, and 500 μmol of hydrogen peroxide, and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 10 hours, and the color of the solid changes from red to Gradually turn into green or even white; the product is centrifuged and dried to obtain loaded nano-gold cyanide. Figure 3 is the XPS spectrum of AuCN nanoparticles, showing that the peak positions of Au4f _5/2 and Au4f _7/2 correspond to the positions of Au(I).

Example 4

Mix 200 mg of loaded nano-silver, 4 mL of acetonitrile, and 200 μmol of hydrogen peroxide together, and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate, and the illumination time is 6 hours, and the color of the solid gradually fades , the product is centrifuged and dried to obtain loaded nano-silver cyanide. Figure 4 is the XRD spectrum of the nano silver cyanide, the product is pure silver cyanide, the chemical formula is AgCN.

Example 5

Mix 100 mg of supported nano-silver oxide-supported mesoporous silica, 4 mL of acetonitrile, and 200 μmol of hydrogen peroxide, and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate, and the illumination time is After 5 hours, the color of the solid gradually became lighter, and the product was centrifuged and dried to obtain loaded nano-silver cyanide.

Example 6

Mix 60 mg of loaded nano-ruthenium, 4 mL of acetonitrile, and 200 μmol of benzyl alcohol together and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 12 hours, and the product is centrifuged, After drying treatment, the loaded nanometer ruthenium cyanide is obtained.

Example 7

Mix 50 mg of loaded nano-platinum, 4 mL of acetonitrile, and 400 μmol of benzyl alcohol together and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 20 hours, and the product is centrifuged, The loaded nano platinum cyanide is obtained after drying treatment.

Example 8

Mix 40 mg of loaded nano-palladium, 4 mL of acetonitrile, and 100 μmol of benzyl alcohol together and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 12 hours, and the product is centrifuged, After drying, the loaded nano palladium cyanide is obtained.

Example 9

Mix 100 mg of loaded nano-ruthenium, 4 mL of acetonitrile, and 200 μmol of hydrogen peroxide together, and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 12 hours, and the product is centrifuged and dried After treatment, the loaded nanometer ruthenium cyanide is obtained.

Example 10

Mix 50 mg of loaded nano-platinum, 5 mL of acetonitrile, and 100 μmol of hydrogen peroxide together, and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 20 hours, and the product is centrifuged and dried After treatment, the loaded nano-platinum cyanide is obtained.

Example 11

Mix 30 mg of loaded nano-platinum, 2 mL of acetonitrile, and 200 μmol of benzyl alcohol together and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate for 20 hours, and the product is centrifuged, The loaded nano platinum cyanide is obtained after drying treatment.

Example 12

Mix 60 mg of supported nano-cuprous oxide, 5 mL of acetonitrile, and 200 μmol of benzyl alcohol together, and stir; then place the above suspension under a 350-watt mercury lamp, stir and illuminate, and the illumination time is 12 hours. After centrifugation and drying, the loaded nano-cuprous cyanide is obtained.

Claims (5)

1. A novel method for preparing metal cyanide nanoparticles, characterized in that the preparation steps of the method are as follows: 1) Loaded metal (or metal oxide) nanoparticles (Au, Ag, Ag ₂ O, Cu, Cu ₂ O, Ru, Pt, Pd, etc.), acetonitrile, benzaldehyde (or benzyl alcohol, hydrogen peroxide) mixed together, the relative content molar ratio is: metal (metal oxide) nanoparticles / benzaldehyde (or benzyl alcohol, hydrogen peroxide) / acetonitrile = 0.1~2.0/1~10/100; 2) Place the above suspension under a 350-watt mercury lamp, stir and illuminate for 1 to 20 hours; 3) The product is centrifuged and dried to obtain loaded metal cyanide nanoparticles. 2. The new method for preparing metal cyanide nanoparticles according to claim 1, characterized in that, loaded metal (metal oxide) nanoparticles, characterized in that: the metal or metal oxide nanoparticles (or Nano silver, nano silver oxide, nano copper, etc.) is Au, Ag, Ag ₂ O, Cu, Cu ₂ O, Ru, Pt or Pd. 3. The novel method for preparing metal cyanide nanoparticles according to claim 1 or 2, characterized in that the metal or metal oxide nanoparticles have a diameter of 1 to 50 nanometers and are loaded on a conventional on a porous carrier. 4. The new method for preparing metal cyanide nanoparticles according to claim 3, characterized in that, the porous carrier is silicon dioxide, aluminum oxide, titanium oxide, carbon or polymer porous material. 5. the novel method for preparing metal cyanide nanoparticles according to claim 4, is characterized in that, described nanometer metal cyanide chemical formula is AuCN, AgCN, CuCN, Pt(CN) ₄ , Pd(CN) ₂ or Ru(CN) ₄ , the particle size is 1-100 nanometers.

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