JP2983075B2 - Method for producing hexaammineiridium trihydroxide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing hexaammineiridium trihydroxide (hereinafter referred to as "HAIrTH").

[0002]

2. Description of the Related Art Conventionally, as a method for producing HAIrTH, silver oxide was added to a hexaammineiridium trichloride solution, and chloride ions were separated by filtration as a precipitate of silver chloride to obtain a HAIrTH solution. Since the reaction between the added silver and the chloride ion does not easily react in an equivalent amount, it is difficult to determine the amount of added silver oxide, and there is a disadvantage that the added silver remains in the solution.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the conventional method, and it is an object of the present invention to provide hexaammineiridium (II).
I) An object of the present invention is to provide a method for producing a HAIrTH solution containing less impurities by exchanging chloride ions and hydroxide ions by bringing a chloride solution into contact with an anion exchange resin.

[0004]

SUMMARY OF THE INVENTION According to the present invention, an aqueous ammonia solution is added to an iridium (III) chloride solution, and the mixture is heated and reacted under pressure to produce hexaammineiridium (III).
A method for producing hexaammineiridium trihydroxide, comprising: synthesizing a chloride solution, heating the synthesized solution to make it weakly ammoniacal, and then bringing the solution into contact with an anion exchange resin, wherein the anion exchange resin is This is a method for producing hexaammineiridium trihydroxide which has been previously treated to the OH ion type and the amount of anion exchange resin to be contacted is twice or more the theoretical exchange amount.

To synthesize a hexaammine iridium (III) chloride solution, an excess of aqueous ammonia is added to an iridium (III) chloride solution, and the reaction is carried out under a pressure of, for example, 1.5 to 5 kg / cm in an autoclave. ^The composition can be synthesized by heating to 100 to 150 ° C. under the pressure of ² and keeping the state for one day or more to react. Then, heating is performed at a temperature of 90 to 98 ° C. to remove excess ammonia, and when the pH of the hexaammine iridium (III) chloride solution becomes 7.5 to 9.0, the heating is stopped and the temperature is lowered to room temperature. By cooling, the desired hexaammineiridium (III) chloride solution can be synthesized. The pH is set to 7.5 to 8.0 to make it weakly ammoniacal in order to complete stable anion exchange at the time of contact with an anion exchange resin as the following operation.

On the other hand, it is preferable to use a strong base anion exchange resin as the anion exchange resin, for example, Diaion SA10A or Diaion SA12A manufactured by Mitsubishi Kasei Kogyo. Before contacting the synthesized hexaammine iridium (III) chloride solution with the anion exchange resin, the method of keeping the anion exchange resin in the OH ion type is, for example, one of the methods described below.
Fill the column with 1 liter of anion exchange resin,
Pass 3 liters of about 5% sodium hydroxide solution at space velocity SV = 2, and then pass pure water also at SV = 2, and pass pure water until the pH of the effluent becomes 7. It is necessary to perform pure water flow until pH = 7,
Also includes removal of sodium ions.

Next, a method of contacting the synthesized hexaammine iridium (III) chloride solution with an anion exchange resin in the form of OH ions may be carried out, for example, by mixing and stirring in a beaker and contacting the solution. It is a simple method to pass the synthesized hexaammine iridium (III) chloride solution through the anion exchange resin layer packed in the column as in the operation to make it into an ion type, and it saves the trouble such as separation. Is more preferable.
Further, the liquid passing speed may be a space velocity SV = 0.1 to 0.5, more preferably SV = 0.2.

The reason why the amount of the anion exchange resin is at least twice the theoretical amount of the anion exchange is due to the relation with the anion exchange equilibrium. It is an indispensable point for perfection. Therefore, the concentration of the synthesized hexaammine iridium (III) chloride solution passed through the anion exchange resin is not particularly limited, but a thin solution requires a concentration operation, and a concentrated solution requires Crystals may be generated, preferably from 40 g / l to
It is preferable to adjust to 100 g / l.

According to the above method, it is possible to produce a HAIrTH solution containing very little impurities. Hereinafter, examples according to the present invention will be described, but the examples do not limit the present invention.

[0010]

Example 1 Chloride iridic acid solution (20 g as Ir)
Ammonia water (28%) 400 in 120 ml
ml in an autoclave and the pressure is increased to 1.5 to 5 kg.
/ Cm ² , a heating temperature of 130 ° C., and stirring at 500 rpm for 24 hours. Next, the solution after the reaction was cooled and filtered, and the filtrate was placed in a beaker and heated to 95 ° C. in a hot water bath. When the pH of the filtrate reached 8.7, the heating was stopped.
Cooled to room temperature. Then, 4 liters of a strong base anion exchange resin (manufactured by Mitsubishi Kasei Kogyo Co., Ltd .: Diaion SA10A) in which the cooled filtrate was previously converted to an OH ion type was charged with a diameter of 5
The space packed into a layer packed in a 0 mm glass column
= 0.2. After passing the solution, pure water was passed through the anion exchange resin layer at SV = 0.2, and the solution was extruded and washed.
2.5 liters of H solution was obtained. 2 of the HARhTH solution
of the hydrochloric acid required for the titration, the amount of O per 1 mol of iridium was determined based on the amount of hydrochloric acid required for the titration.
H ions were almost 3 mol, and it was confirmed that the ions were HAIrTH. The solution had a chlorine ion concentration of 10
It was 0 mg / l or less.

[0011]

Example 2 Chloride iridic acid solution (20 g as Ir)
Ammonia water (28%) 400 in 120 ml
ml in an autoclave to increase the pressure to 1.5 to 5 kg.
/ Cm ² , a heating temperature of 130 ° C., and stirring at 500 rpm for 48 hours. Then, the solution after the reaction was cooled and filtered, and the filtrate was placed in a beaker and heated to 95 ° C. in a hot water bath. When the pH of the filtrate reached 8.0, the heating was stopped.
Cooled to room temperature. Then, 4 liters of a strong base anion exchange resin (manufactured by Mitsubishi Kasei Kogyo Co., Ltd .: Diaion SA10A) in which the cooled filtrate was previously converted to an OH ion type was charged with a diameter of 5
The space packed into a layer packed in a 0 mm glass column
= 0.2. After passing the solution, pure water was passed through the anion exchange resin layer at SV = 0.2, extrusion washed, and HAIrT
2.5 liters of H solution was obtained. 2 of the HAIrTH solution
of the hydrochloric acid required for the titration, the amount of O per 1 mol of iridium was determined based on the amount of hydrochloric acid required for the titration.
H ions were almost 3 mol, and it was confirmed that the ions were HAIrTH. The solution had a chlorine ion concentration of 10
It was 0 mg / l or less.

[0012]

Conventional example: 400 ml of aqueous ammonia (28%) in 120 ml of an iridium chloride solution (containing 20 g as Rh)
And the pressure is increased to 1.5 to 5 kg / c in the autoclave.
m ² , heating temperature of 120 ° C., stirring at 500 rpm, 2
The reaction was performed for 4 hours. Next, the solution after the reaction was cooled and filtered, and the filtrate was put into a beaker and heated to 95 ° C. in a hot water bath. When the pH of the filtrate reached 7.2, the heating was stopped and cooled to room temperature. Then, silver oxide powder was added to the cooled filtrate under stirring, and when it was confirmed that white precipitation of silver chloride did not occur, the addition of silver oxide was stopped, and the mixture was separated by filtration and washed with pure water. Most of the filtrate was a HAIrTH solution, but contained 100 mg / l of silver in the solution.
Chloride ion was contained at 100 mg / l.

[0013]

As is apparent from the above description, in the conventional method, silver oxide is added, and the precipitate of silver chloride is separated by filtration to obtain HAIr.
Although a TH solution was produced, the HAIrTH solution contained many impurities due to silver remaining in the solution. However, according to the method of the present invention, chloride ions in the solution can be extremely reduced, Since no silver oxide is used,
That is, a stable product having a small amount of impurities in a solution can be produced.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C01G 55/00 CA (STN)

Claims (2)

(57) [Claims] 1. An excess of aqueous ammonia is added to an iridium (III) chloride solution, and the mixture is heated and reacted under pressure to synthesize a hexaammineiridium (III) chloride solution, and the synthesized solution is heated. A method for producing hexaammineiridium trihydroxide, which is made weakly ammoniacal and then brought into contact with an anion exchange resin. 2. The hexaammine iridium according to claim 1, wherein the anion exchange resin has been previously treated to an OH ion type, and the amount of the anion exchange resin to be contacted is at least twice the theoretical exchange amount. A method for producing trihydroxide.