JP3457682B2 - Noble metal hydrosol and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a conductivity at room temperature of 50 .mu.s in which hydrogenation catalysts , combustion catalysts for purification of exhaust gas, electroless plating catalysts, and ionic impurities which can be used for dyeing are removed as much as possible. / Cm or less noble metal hydrosol and a method for producing the same.

[0002]

2. Description of the Related Art As is well known, a noble metal hydrosol is an extremely fine and uniform noble metal colloidal particle dispersed in an aqueous dispersion medium, and is used as a hydrogenation catalyst , a combustion catalyst for exhaust gas purification, an electroless plating catalyst. It has been widely used for dyeing.

Recently, as one of the methods for producing a noble metal hydrosol, a method has been proposed in which an aqueous solution of a noble metal salt is subjected to reduction treatment in the presence of a surfactant to obtain a noble metal hydrosol (Japanese Patent Laid-Open No. 59-120249). Has been done.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
By utilizing the method described in 20249, it is possible to obtain a noble metal hydrosol containing extremely fine and uniform noble metal colloidal particles and stable for a long period of time. However, in the obtained noble metal hydrosol, Na ions and chlorine are contained. There is a problem that a large amount of ionic impurities such as ions and nitrate ions remain, and inevitably only those having high conductivity are obtained.

The reason why a large amount of ionic impurities remain is that water-soluble chlorides such as chloroauric acid, silver nitrate, chloroplatinic acid, palladium (II) chloride, rhodium (III) chloride and ruthenium chloride are used as starting materials for precious metal hydrosols. It is considered that this is due to the fact that the substances and nitrates are used, and that the surfactants, water-soluble polymers and reducing agents used when forming the noble metal hydrosol inevitably contain Na ions and chlorine ions.

Ionic impurities such as Na ions and chlorine ions, which directly affect the conductivity value of the noble metal hydrosol, remain in the noble metal hydrosol at a level of several hundred ppm, and such ionic impurities are present in a large amount. When using noble metal hydrosols for hydrogenation catalysts , combustion catalysts for exhaust gas purification, electroless plating catalysts, dyeing, etc., the presence of residual ionic impurities causes the elution of the plating substrate material, catalytic action, and dyeing. It adversely affects the subsequent robustness. This is described, for example, in Chemical Review No. 34: Catalyst design (published by the Japan Society for Publishing, 1982), "13. Catalyst for cleaning automobile exhaust gas", 5.4 "Selection of catalytically active substance", "When chlorine-containing substance is used as Pt compound, It is reported that the activity increases as the residual Cl is removed, and that when a raw material containing no chlorine such as [Pt (NH ₃ ) ₄ ] (NO ₃ ) ₂ is used, the activity is high regardless of the treatment. ” Is as described.

The present invention aims to solve the above problems of conventional noble metal hydrosols.

[0008]

In order to solve the above technical problems, the present inventors have conducted extensive studies over a long period of time, and as a result, have found that an aqueous solution of a noble metal salt is treated with a surfactant and / or a highly water-soluble solution. Focusing on a large amount of ionic impurities contained in the noble metal hydrosol obtained by the reduction treatment in the presence of molecules, and contacting the noble metal hydrosol with an ion exchange resin to capture the ionic impurities It was found that ionic impurities can be removed, and the conductivity is small, and a precious metal hydrosol suitable for combustion catalysts such as hydrogenation catalysts and exhaust gas purification, electroless plating catalysts and dyeing can be obtained, and the present invention has been completed. It was

That is, the present invention relates to precious metal colloidal particles selected from gold, silver, platinum, palladium, rhodium and ruthenium and a cationic surfactant, an anionic surfactant, a nonionic surfactant and a water-soluble agent. Na ion which is an ionic impurity and contains one or more kinds of ionic polymers
And the total amount of Cl ions is 20 ppm or less,
Noble metal hydrosol and gold, silver, platinum, palladium, which has a conductivity of 50 μs / cm or less at room temperature,
Reduction treatment of an aqueous solution of a noble metal salt selected from rhodium and ruthenium in the presence of one or more of cationic surfactants, anionic surfactants, nonionic surfactants and water-soluble polymers. to form a precious metal hydrosol, then the <br/>, characterized in that as much as possible remove ionic impurities the noble metal hydrosol is contacted with the ion exchange resin contained in the said precious metal hydrosol A method for producing a noble metal hydrosol.

Next, various conditions for carrying out the present invention will be described.

The noble metal hydrosol of the present invention can be prepared by the following method.

That is, while stirring an aqueous solution of a noble metal salt selected from gold, silver, platinum, palladium, rhodium and ruthenium, a cationic surface active agent, an anionic surface active agent and a nonionic surface active agent are added thereto. A dispersion-stable and transparent noble metal hydrosol can be obtained by adding one or two or more of an agent and a water-soluble polymer and subsequently adding a reducing agent for reduction treatment.

Noble metal salts that can be used as starting materials include water-soluble chlorides and nitrates of noble metals, such as chloroplatinic acid, silver nitrate, chloroauric acid, palladium (II) chloride and rhodium chloride (III). ) And ruthenium (III) chloride can be used. Further, it is used so that the concentration of the noble metal salt in the hydrosol is in the range of 0.01 to 10 mmol / l.

As the surfactant and the water-soluble polymer, a cationic surfactant such as stearyltrimethylammonium chloride, an anionic surfactant such as sodium dodecylbenzenesulfonate, polyethylene glycol mono-p-nonylphenyl ether, etc. Nonionic surfactants such as and water-soluble polymers such as polyvinyl alcohol and polyvinylpyrrolidone can be used. In use, these surfactants and water-soluble polymers can be used alone or in combination of two or more. The concentration of the surfactant and the water-soluble polymer is used in the range of 0.005 to 0.1%.

The reducing treatment can be carried out by a known method using a reducing agent, and examples of the reducing agent include alkali metal borohydrides such as sodium borohydride and potassium borohydride, and boron such as dimethylamine borane. In addition to the system-based reducing agent, a phosphorus-based reducing agent such as sodium hypophosphite, formaldehyde, hydrazine and the like are used. The amount of the reducing agent is equimolar or more, preferably 2 to 4 times the molar amount of the noble metal salt as the starting material.

The noble metal hydrosol having a conductivity at room temperature of 50 μs / cm or less in which ionic impurities are removed as much as possible in the present invention can be prepared by the following method.

That is, the noble metal hydrosol obtained by the above method is brought into contact with an ion exchange resin to remove ionic impurities remaining in the noble metal hydrosol as much as possible, so that the conductivity of 50 μs / cm or less at room temperature. A noble metal hydrosol having a certain degree is obtained.

The conductivity of the noble metal hydrosol is 50 μs / c
In order to reduce the amount to m or less, it is necessary to remove the ionic impurities remaining in the noble metal hydrosol so that the total amount of Na ions and Cl ions is 20 ppm or less.

As the ion exchange resin used, generally used ion exchange resins can be used. For example,
H-type cation exchange resin, OH-type anion exchange resin and the like can be used. Further, an ion exchange resin can be appropriately selected according to the type of ionic impurities remaining in the noble metal hydrosol, and two or more ion exchange resins can be used in combination.

The amount of the ion exchange resin is preferably at least a theoretical equivalent for ion exchange of the ionic impurities remaining in the noble metal hydrosol.

In order to bring the noble metal hydrosol into contact with the ion exchange resin, the ionic impurity-containing noble metal hydrosol may be passed through one or more columns filled with the ion exchange resin.

[0022]

The most important point in the present invention is ion exchange of a noble metal hydrosol containing one or more of a cationic surfactant, an anionic surfactant, a nonionic surfactant and a water-soluble polymer. When brought into contact with a resin, the ionic impurities remaining in the noble metal hydrosol can be efficiently captured by the ion exchange resin, so that the ionic impurities can be removed as much as possible and the conductivity at room temperature can be reduced. The fact is that a noble metal hydrosol having a degree of 50 μs / cm or less is obtained.

[0023]

The present invention will be described below with reference to examples.

The room temperature conductivity in the examples is measured by using a personal SC meter (Model SC82: manufactured by Yokogawa Electric Co., Ltd.).

Example 1 10 ml of a 0.1 mol / l chloroauric acid aqueous solution was added to 886 ml of ion-exchanged water, and the mixture was further stirred for 5 minutes.
% Stearyltrimethylammonium chloride solution 4 ml, and then 0.04 mol / l sodium borohydride aqueous solution 100 ml was dripped, the color of the solution suddenly changed to red, gold concentration 1.0 mmol / l, Na
1 l of gold hydrosol containing 95 ppm ion and 170 ppm Cl ion and having a conductivity at room temperature of 550 μs / cm
Got

First, 100 ml of the above gold hydrosol was
Strongly acidic cation exchange resin (trade name: Amberlite I
R-120B: manufactured by Organo Co., Ltd. was passed through a small column filled with 10 ml of an ion-exchange resin regenerated into an H-type cation-exchange resin by a conventional method at a flow rate of 3 ml / min, and then after passing the liquid. The above-mentioned gold hydrosol was further filled with 10 ml of a regenerated ion-exchange resin of a strong base anion exchange resin (trade name: Amberlite IR-400: manufactured by Organo Co., Ltd.) which was regenerated into an OH-type anion exchange resin by a conventional method. The solution was passed through the small column at a flow rate of 3 ml / min. After the ion exchange treatment, the gold hydrosol was below the Na ion detection limit, Cl
It contained 1 ppm of ions and had a room temperature conductivity of 11 μs / cm.

Example 2 10 ml of a 0.1 mol / l silver nitrate aqueous solution was added to 886 ml of ion-exchanged water, and the mixture was further stirred at 5% with vigorous stirring.
Sodium dodecylbenzene sulfonate aqueous solution 4ml
After adding 100 ml of 0.04 mol / l sodium borohydride aqueous solution, the color of the solution suddenly changes to yellow, the silver concentration is 1.0 mmol / l, the Na ion content is 105 ppm, and the conductivity at room temperature is 1 l of a silver hydrosol with 230 μs / cm was obtained.

1 l of the above-mentioned silver hydrosol was mixed with a strongly acidic cation exchange resin (trade name: Amberlite IR-120).
B: Organo Co., Ltd. was passed through a column filled with 100 ml of regenerated ion exchange resin of H-type cation exchange resin by a conventional method at a flow rate of 10 ml / min. In the silver hydrosol after the ion exchange treatment, Na ion was below the detection limit and the conductivity at room temperature was 10 μs / cm.

Example 3 10 ml of a 0.1 mol / l chloroplatinic acid aqueous solution was added to 886 ml of ion-exchanged water, and 5% of polyethylene glycol-p-nonylphenyl ether (polymerization of polyethylene glycolicol portion was further added with vigorous stirring. (Degree = 10)
After adding 4 ml of the aqueous solution and adding 100 ml of 0.04 mol / l aqueous solution of sodium borohydride, the color of the solution suddenly changed to black brown and the platinum concentration was 1.0 mmol / l.
l, Na ion 92ppm, Cl ion 280ppm
1 l of platinum hydrosol was obtained which contained room temperature conductivity of 750 μs / cm.

100 ml of the above platinum hydrosol was first ion-exchanged by regenerating a strongly acidic cation exchange resin (trade name: Amberlite IR-120B: manufactured by Organo Co.) into an H-type cation exchange resin by a conventional method. Pass it through a small column filled with 10 ml of resin at a flow rate of 3 ml / min,
Next, the platinum hydrosol after passing the liquid is further treated with a strongly basic anion exchange resin (trade name: Amberlite IR-40).
0: Organo Co., Ltd. was passed through a small column filled with 10 ml of regenerated ion exchange resin of OH type anion exchange resin by a conventional method at a flow rate of 3 ml / min. The platinum hydrosol after the ion exchange treatment contained Na ion detection limit or less, Cl ion 0.5 ppm, and had a room temperature conductivity of 8 μm.
It was s / cm.

Example 4 25 ml of a 0.1 mol / l palladium chloride aqueous solution was added to 715 ml of ion-exchanged water, 10 ml of a 5% polyvinyl alcohol aqueous solution was further added with vigorous stirring, and then 0.04 mol / l of hydrogen was added. When 250 ml of an aqueous solution of sodium borohydride was dripped, the color of the solution suddenly changed to blackish brown, the palladium concentration was 2.5 mmol / l, 520 ppm of Na ion and 620 ppm of Cl ion were contained, and the conductivity of the room temperature palladium hydrosol was 2200 μs / cm. 1 l was obtained.

First, 1 l of the above-mentioned palladium hydrosol was regenerated into a H-type cation exchange resin by a conventional method from a strongly acidic cation exchange resin (trade name: Amberlite IR-120B: manufactured by Organo Corporation). Ion exchange resin 100 ml
Flow through the column packed with at a flow rate of 10 ml / min,
Next, the palladium hydrosol after passing the liquid is further subjected to a strongly basic anion exchange resin (trade name: Amberlite IR
-400: Organo Co., Ltd. was passed through a column filled with 500 ml of regenerated ion exchange resin of OH type anion exchange resin by a conventional method at a flow rate of 25 ml / min. After the ion exchange treatment, the palladium hydrosol contained below the Na ion detection limit, 0.5 ppm of Cl ions, and had a room temperature conductivity of 14 μs / cm.

Example 5 10 ml of a 0.1 mol / l rhodium chloride aqueous solution was added to 886 ml of ion-exchanged water, and 4 ml of a 5% sodium lauryl sulfate aqueous solution was further added with vigorous stirring, and then 0.04 mol / l of When 100 ml of an aqueous solution of sodium borohydride was dropped, the color of the solution suddenly changed to black, the rhodium concentration was 1.0 mmol / l, the Na ion contained 110 ppm and the Cl ion contained 142 ppm, and the room temperature conductivity was 520 μs / cm. Sol 1
1 was obtained.

First, 1 l of the above rhodium hydrosol was regenerated into a H-type cation exchange resin by a conventional method from a strongly acidic cation exchange resin (trade name: Amberlite IR-120B: manufactured by Organo Corporation). Ion exchange resin 100 ml
Flow through the column packed with at a flow rate of 10 ml / min,
Next, the rhodium hydrosol after passing the liquid is further treated with a strongly basic anion exchange resin (trade name: Amberlite IR-
400: Organo Co., Ltd. was passed through a column filled with 100 ml of regenerated ion exchange resin of OH type anion exchange resin by a conventional method at a flow rate of 12 ml / min. The rhodium hydrosol after the ion exchange treatment contained Cl ions of 2 ppm or less at the Na ion detection limit or less, and had a room temperature conductivity of 20 μs / cm.

Example 6 25 ml of a 0.1 mol / l aqueous solution of ruthenium chloride was added to 715 ml of ion-exchanged water, 10 ml of a 5% aqueous solution of stearyltrimethylammonium chloride was further added with vigorous stirring, and then 0.04 mol / l was added. When 250 ml of sodium borohydride aqueous solution is dripped, the color of the solution suddenly changes to red black and the ruthenium concentration is 2.5.
It contains 230 ppm of Na ion and 625 ppm of Cl ion at a mmol / l, and has a room temperature conductivity of 1710 μs / cm
1 l of ruthenium hydrosol was obtained.

1 l of the above-mentioned ruthenium hydrosol was first regenerated into a H-type cation exchange resin by a conventional method using a strongly acidic cation exchange resin (trade name: Amberlite IR-120B: manufactured by Organo Co.). Ion exchange resin 100 ml
Flow through the column packed with at a flow rate of 10 ml / min,
Then, the ruthenium hydrosol after passing the liquid is further treated with a strongly basic anion exchange resin (trade name: Amberlite IR
-400: Organo Co., Ltd. was passed through a column filled with 500 ml of regenerated ion exchange resin of OH type anion exchange resin by a conventional method at a flow rate of 25 ml / min. The ruthenium hydrosol after the ion exchange treatment contained 0.5 ppm or less of Cl ions below the Na ion detection limit, and had a room temperature conductivity of 15 μs / cm.

[0037]

As described above, according to the present invention,
As shown in the above-mentioned Examples, a large amount of ionic impurities such as Na ions and Cl ions, which adversely affect the cause of elution of the plated substrate material, the catalytic action and the loss of fastness after dyeing, remain. By contacting the noble metal hydrosol with the ion exchange resin, the ionic impurities in the noble metal hydrosol can be efficiently trapped, so that the ionic impurities in the noble metal hydrosol are removed as much as possible, and the conductivity of the noble metal hydrosol at room temperature is reduced. It can be 50 μs / cm or less.

Therefore, the noble metal hydrosol according to the method of the present invention is suitable as a currently required hydrogenation catalyst , combustion catalyst for exhaust gas purification, electroless plating catalyst and dyeing material.

Continued front page       (56) References JP-A-59-120249 (JP, A)                 JP-A-63-283743 (JP, A)                 JP-A-2-258032 (JP, A)                 JP 54-119374 (JP, A)                 Japanese Patent Publication Sho 49-14448 (JP, B1)                 US Patent 3992512 (US, A)

Claims (2)

(57) [Claims] 1. A noble metal colloidal particle selected from gold, silver, platinum, palladium, rhodium and ruthenium, a cationic surfactant, an anionic surfactant, a nonionic surfactant and a water-soluble polymer. Na ion and Cl ion, which are one or more kinds and are ionic impurities
And a total room temperature conductivity of 20 ppm or less and room temperature conductivity of 50 μs / cm or less. 2. An aqueous solution of a noble metal salt selected from gold, silver, platinum, palladium, rhodium and ruthenium is added to a cationic surface active agent, an anionic surface active agent, a nonionic surface active agent and a water-soluble high-solubility solution. The noble metal hydrosol is subjected to reduction treatment in the presence of one or more molecules to form a noble metal hydrosol, and then the noble metal hydrosol is contacted with an ion exchange resin to minimize the ionic impurities contained in the noble metal hydrosol. The method for producing a noble metal hydrosol according to claim 1 , characterized in that the noble metal hydrosol is removed.