JP2588591B2 - Method for producing hexaammineiridium salt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a raw material for producing various iridium complex compounds, a raw material for electroless plating or electroplating of iridium, and a hexagon used as a raw material for iridium catalyst. The present invention relates to a method for producing an ammine iridium salt.

(Prior art and its problems) Conventionally, as a method for producing hexaammine iridium (III) chloride ([Ir (NH ₃ ) ₆ ] Cl ₃ ), there has been proposed a method in which a nitrate of hexaammine iridium (III) is salified and produced. And chloropentaammine iridium (III) chloride by further amminating.

Among the conventional methods, the latter involves dissolving iridium (III) chloride in water, adding ammonium chloride and ammonium carbonate in a reaction vessel equipped with a reflux condenser, and refluxing on a water bath.

Then, after refluxing under a pressure of 50 to 100 mmHg for 5 to 5.5 hours, the formed precipitate is filtered and extracted with dilute hydrochloric acid to remove simultaneously formed heterogeneous iridium compounds ([IrCl ₂ (NH ₃ ) ₄ ] Cl). The remaining solid is dissolved in hot water, filtered, and the filtrate is concentrated by heating, and hydrochloric acid is added to precipitate crystals.

After the precipitate is recrystallized, it is washed with hydrochloric acid, then with alcohol and dried to obtain chloropentaammineiridium (III) salt.

Ammonia water was added to the iridium (III) salt, sealed in a glass tube, and heated in an electric furnace at 140 ° C. for 48 hours.
Crystals of hexaammineiridium (III) chloride can be obtained.

As a disadvantage of the above-mentioned production method, an operation of extracting with dilute hydrochloric acid is necessary to remove different iridium compounds ([IrCl ₂ (NH ₃ ) ₄ ] Cl) which are formed at the same time, resulting in a low production yield and pure chloropentaammine. -It is necessary to produce an iridium (III) salt, and the production efficiency is poor.

In the former, the pure chloropentaammineiridium (III) salt obtained by the above method is reacted with phosphate and then nitric acid is added thereto to form hexaammineiridium (II).
Concentrated hydrochloric acid was added to the mixture, followed by repeated heating and evaporation, and concentrated to dryness. After dissolving about 10 times the amount of water, the mixture was heated to 0 ° C.
When 15 times the amount of fuming hydrochloric acid is added, crystals of hexaammineiridium (III) chloride can be obtained.

This method has the disadvantage that the operation is more complicated and the production efficiency is lower than the above method.

(Object of the Invention) The present invention has been made in order to solve the above-mentioned drawbacks of the conventional method, and is intended to improve the production yield and to provide a simple chloropentaammine iridium (III) salt without producing it. It is intended to provide a method for producing hexaammineiridium (III) chloride in a short time by a simple method.

(Means for solving the problem) After reacting ammonia with the iridium (III) chloride solution, hydrochloric acid is added to form a precipitate, and the precipitate is heated in an aqueous ammonia at 100 to 150 ° C under pressure to precipitate. Is dissolved, and the solution is filtered and concentrated, and then acetone is added for crystallization, thereby producing a hexaammineiridium salt.

 Hereinafter, the present invention will be described in detail.

The raw material of iridium used in the present invention is iridium (III) chloride crystal or iridium (III) chloride solution dissolved in dilute hydrochloric acid or water to obtain 100 to 300 g / iridium.
Concentration.

Next, 28% aqueous ammonia and ammonium chloride and / or ammonium carbonate are added, and the mixture is heated under stirring in a reaction vessel equipped with a reflux to amminate.

The amount of ammonium to be added is 2-3 based on the amount of iridium.
The amount may be doubled, and the method of addition is not particularly limited, but the method of adding in several portions is more preferable.

The heating temperature is about 70 ° C. in an oil bath or a hot water bath, and the heating time is 25 to 30 hours to complete the reaction.

Next, the precipitate was separated by filtration, and then the precipitate was added to the filtrate.
When 0.7% to 1.2 times the volume of the filtrate is added to the filtrate, a yellow precipitate is formed.

The precipitate is filtered, and the filtrate is concentrated by heating to precipitate crystals and flesh-colored precipitate, and the crystals and flesh-colored precipitate are filtered.

The flesh color precipitate and the crystals are treated with dilute hydrochloric acid and filtered to obtain only flesh color precipitate.

Next, the flesh color precipitate and the yellow precipitate obtained above are washed with alcohol, and then transferred to a pressure vessel, 28% aqueous ammonia is added 7 to 12 times the amount of iridium, and the temperature is 100 to 1 with stirring.
The reaction is carried out while maintaining the temperature at 50 ° C. and the pressure at 20 to 25 atm.

If the amount of aqueous ammonia added is less than 7 times, it is not enough.
If it is more than twice, it is excessive and the reagent is wasted.

The reaction does not proceed at a heating temperature of 100 ° C. or less, and a special vessel or heating device is required for the reaction at a temperature of 150 ° C. or more.

At a pressure of 20 atm or less, the reaction does not proceed, and at a pressure of 25 atm or more, the reaction vessel becomes large in size, which is not convenient.

 A reaction time of at least 20 hours is sufficient.

After the reaction is completed, the mixture is filtered to remove impurities, the filtrate is concentrated to remove excess ammonia, and acetone is added in an amount of 5 to 5 times the concentration of the filtrate to form a white precipitate.

The color precipitate is filtered, washed with acetone, and then dried in a vacuum drier to obtain high-purity hexaammineiridium (III) chloride.

Hereinafter, examples of the present invention will be described, but the examples do not limit the present invention.

(Example 1) Iridium (III) chloride crystal was reduced to 50 g as iridium.
Dissolve by adding 50 ml of 35% hydrochloric acid and 130 ml of water, and transfer to a flask equipped with a reflux condenser.
l, 200 ml of water, 29.5 g of ammonium chloride and 50.7 g of ammonium carbonate, and heat at 65 ° C. in an oil bath with stirring.

After 6.5 hours, add 19.4 g of ammonium chloride and 52.0 g of ammonium carbonate, and continue heating.After 20 hours, add 17.3 g of ammonium chloride, 34.8 g of ammonium carbonate, and continue heating.
After an hour, the flask was removed and cooled, and the solution was filtered.

When 35% hydrochloric acid (1) was added to the filtrate and stirred, a yellow precipitate was formed. The precipitate was filtered, and the filtrate was transferred to an evaporator, concentrated by heating to form a precipitate of crystals and flesh color, cooled, and filtered.

(Example 2) In the same manner as in Example 1, 50 g of iridium (III) chloride crystal as iridium was dissolved by adding 50 ml of 35% hydrochloric acid and 130 ml of water, and the solution was transferred to a flask equipped with a reflux condenser.
% Ammonia water 100ml, water 300ml and ammonium chloride 51.1
g and 93.5 g of ammonium carbonate are added and heated at 65 ° C. in an oil bath with stirring.

After 12 hours, 11.0 g of ammonium chloride and 68.3 g of ammonium carbonate were added and heating was continued. After 24 hours, the flask was taken out and cooled, and the solution was filtered.

When 35% hydrochloric acid (1) was added to the filtrate and stirred, a yellow precipitate was formed. The precipitate was filtered, and the filtrate was transferred to an evaporator, concentrated by heating to form a precipitate of crystals and flesh color, cooled, and filtered.

Next, the crystals obtained in Example 1 and the flesh-colored precipitate were combined with the crystals obtained in Example 2 and the flesh-colored precipitate, and 500 ml of 3N hydrochloric acid was added.
Heat to 0 ° C and filter to obtain only a flesh colored precipitate.

After the yellow precipitate and the flesh-colored precipitate obtained in Example 1 and Example 2 were washed with ethanol, the precipitate was transferred into an autoclave containing a glass container as a pressure container, and 28% aqueous ammonia was added thereto. 500 ml was added and reacted by heating in an oil bath.

The heating temperature was 145 ° C. and the pressure was 30 atm. After cooling for 24 hours, the mixture was filtered, the filtrate was put into a beaker, and concentrated by heating on a hot plate to a volume of about 300 ml.

After cooling, acetone 2 was added and stirred to produce a white precipitate, which was filtered and washed with acetone.

After the white precipitate was dried in a vacuum dryer, the obtained white precipitate was weighed to give 63.6 g and the yield as iridium was 41%. X-ray diffraction, thermal analysis and XPS analysis showed that Ammine iridium (III) chloride ([Ir (NH ₃ ) ₆ ] Cl ₃ ).

(Example 3) In the same manner as in Example 1, iridium (III) chloride crystals were dissolved as iridium in 50 g by adding 50 ml of 35% hydrochloric acid and 130 ml of water, and transferred to a flask equipped with a reflux condenser.
100 ml of aqueous ammonia and 200 ml of water are added and heated at 60 ° C. in an oil bath with stirring.

Between 2 hours and 8.5 hours, 28% aqueous ammonia was added four times in 100 ml portions and heating was continued. After 15 hours, ammonium carbonate was added.
33.8 g was added thereto and reacted at a heating temperature of 70 ° C., 29 hours later, the flask was taken out and cooled, and the solution was filtered.

When 500 ml of 35% hydrochloric acid was added to the filtrate and stirred, a yellow precipitate was formed. The precipitate was filtered, and the filtrate was transferred to an evaporator, concentrated by heating to form a precipitate of crystals and flesh color, cooled, and filtered.

Next, 500 ml of 3N-hydrochloric acid was added, and the mixture was allowed to stand for 2 hours and filtered to obtain only a flesh-colored precipitate.

The yellow precipitate and the flesh-colored precipitate were washed with ethanol, and the precipitates were transferred into an autoclave containing a glass container as a pressurized container.
l was added and reacted by heating in an oil bath.

The heating temperature was 130 ° C. and the pressure was 25 atm. After 30 hours, the mixture was cooled and filtered. The filtrate was placed in a beaker, and concentrated by heating on a hot plate to a volume of about 200 ml.

After cooling, 1.5 parts of acetone were added and stirred to produce a white precipitate, which was filtered and washed with acetone.

The white precipitate was dried in a vacuum dryer, and the obtained white precipitate was weighed. The yield was 36.0 g and the yield as iridium was 35%. X-ray diffraction, thermal analysis and XPS analysis showed that Ammine iridium (III) chloride ([Ir (NH ₃ ) ₆ ] Cl ₃ ).

(Effects of the Invention) The present invention provides a high-purity [Ir (N
H _{3) 5} Cl] in After taken out Cl _2, in the method of further methods and [Ir (NH ₃ that ammine reduction) _6] (NO _{3) 3} compounds are converted to chloro complexes, long time to manufacture However, the production yield was as low as about 30%, but these problems could be solved with simple operations. Even if heterogeneous iridium ammine chloro complex and ammonium chloride were mixed as impurities, the problem was not solved. High purity hexaammine iridium (III) chloride ([Ir (NH ₃ ) ₆ ]
Cl ₃ ) can be obtained with an improved yield of about 35% to 40%, so that the production time is shortened and the effect is great.

According to the present invention, production of various iridium compounds and utilization for catalysts and the like can be greatly expected.

Claims (1)

(57) [Claims] 1. After reacting ammonia with an iridium (III) chloride solution, a precipitate is formed by adding hydrochloric acid, and the precipitate is heated at 100 to 150 ° C. under pressure in aqueous ammonia to dissolve the precipitate. A method for producing a hexaammineiridium salt, which comprises filtering a solution, concentrating the solution, and then crystallizing the solution by adding acetone.