Process for the production of high purity iridium(III)chloride hydrate

Abstract

Process for the production of high purity iridium(III) chloride hydrate, comprising the steps of: (1) providing at least one material selected from the group consisting of solid H.sub.2[IrCl.sub.6] hydrate, aqueous, at least 1 wt. % H.sub.2[IrCl.sub.6] solution, and solid IrCl.sub.4 hydrate; (2) adding, to the at least one material provided in step (1), at least one monohydroxy compound selected from the group consisting of monohydroxy compounds that are miscible with water at any ratio, primary monoalcohols comprising 4 to 6 carbon atoms, and secondary monoalcohols comprising 4 to 6 carbon atoms at a molar ratio of Ir(IV):monohydroxy compound=1:0.6 to 1000, and allowing to react for 0.2 to 48 hours in a temperature range from 20 to 120° C., followed by removing volatile components from the reaction mixture thus formed.

Claims

1. A process for the production of high purity iridium(III) chloride hydrate having the formula IrCl.sub.3.Math.×H.sub.2O.Math.yHCl, wherein x=1.5 to 5 and y=0 to 1, the process comprising: (1) providing at least one material selected from the group consisting of solid H2[IrC16] hydrate, aqueous, at least 1 wt. % H.sub.2[IrCl.sub.6] solution, and solid IrCl.sub.4 hydrate; (2) adding, to the at least one material provided in step (1), at least one monohydroxy compound selected from the group consisting of monohydroxy compounds that are miscible with water at any ratio, primary monoalcohols comprising 4 to 6 carbon atoms, and secondary monoalcohols comprising 4 to 6 carbon atoms at a molar ratio of Ir(IV): monohydroxy compound from 1: 0.6 to 1_1000, and allowing to react for 0.2 to 48 hours in a temperature range from 20 to 120° C., followed by removing volatile components from the reaction mixture thus formed.

2. The process of claim 1, whereby the at least one monohydroxy compound is selected from the group consisting of methanol, ethanol, and isopropanol.

3. The process of claim 1, whereby the molar ratio of Ir(IV): monohydroxy compound(s) is from 1: 0.6 to 1:100.

4. The process of claim 1, whereby the reaction temperature is 50 to 100° C.

5. The process of claim 1, whereby the reaction time is in the range of 0.5 to 6 hours.

6. The process of claim 1, whereby step (2) is terminated, before a formation of metallic iridium commences.

7. The process of claim 1, whereby the course of the reaction and/or completion of the reaction is/are monitored by ESR spectroscopy.

8. The process of claim 1, whereby selection of chemical and physical parameters of the process takes place specifically through the application of ESR spectroscopy, such that step (2) ends or can be terminated, before a formation of metallic iridium commences.

9. The process of claim 1, whereby the volatile components are removed by distillation or evaporation.

10. The process of claim 9, whereby the distillation or evaporation takes place at temperatures in the range of 30 to 120° C. acting from outside on the container containing the reaction mixture thus formed.

11. The process of claim 9, whereby the distillation or evaporation takes place supported by a vacuum.

Description

EXAMPLES

Example 1 (Production of High Purity Iridium(III) Chloride Hydrate)

(1) A total of 86.65 g aqueous H.sub.2[IrCl.sub.6] solution (Ir content 24.8 wt. %) were weighed in a 2000 mL flask, and 22.27 g ethanol were added. The flask was attached to a rotary evaporator and the content of the flask was heated to a temperature of 71° C. The condensate tank was closed such that any condensate produced would reflux. After 4.5 hours at 71° C., the pressure was reduced to 80 mbar and the volatile components were removed for 40 hours at a heating bath temperature of 80° C. An olive-green amorphous solid was obtained as the product. There was no formation of metallic iridium.

(2) Elemental Analysis of the Product:

(3) Iridium: 52.9 wt. %

(4) Hydrogen: 1.6 wt. %

(5) Chlorine: 33.6 wt. %

(6) Oxygen: 11.0 wt. %

(7) The ratio of Ir(III) to Ir(IV) in the product thus obtained, determined by ESR spectroscopy, was ≥99.9%: ≤0.1%.

(8) Further Examples 2 to 4 were treated analogous to Example 1. There was no formation of metallic iridium in any of the examples. The following table shows an overview of Examples 1 to 4.

(9) TABLE-US-00001 Example 1 Example 2 Material provided in step (1) 86.65 g aqueous H.sub.2[IrCl.sub.6] 86.96 g aqueous H.sub.2[IrCl.sub.6] solution (Ir content 24.8 solution (Ir content 23.0 wt. %, 92% Ir(IV):8% Ir(III)) wt. %, 93% Ir(IV):7% Ir(III)) Monohydroxy compound 22.27 g ethanol 4.47 g ethanol Reaction time (h) 4.5 14 Reaction temperature (° C.) 71 73 Duration of the removal of 40 38 volatile components (h) Heating bath temperature 80 (at 80 mbar) 80 (at 80 mbar) (° C.) Product data: Ir (wt. %) 52.9 51.9 H (wt. %) 1.6 2.4 Cl (wt. %) 33.6 32.2 O (wt. %) 11.0 16.8 Ir(III):Ir(IV) (by ESR ≥99.9%:≤0.1% ≥99.9%:≤0.1% spectroscopy) Example 3 Example 4 Material provided in step (1) 40.9 g aqueous H.sub.2[IrCl.sub.6] 41.46 g aqueous H.sub.2[IrCl.sub.6] solution (Ir content 22.0 solution (Ir content 21.7 wt. %, 94% Ir(IV):6% Ir(III)) wt. %, 93% Ir(IV):7% Ir(III)) Monohydroxy compound 13.23 g isopropanol 13.1 g 1-butanol Reaction time (h) 5.5 5 Reaction temperature (° C.) 70 72 Duration of the removal of 24 26 volatile components (h) Heating bath temperature 80 (at 60 mbar) 80 (at 50 mbar) (° C.) Product data: Ir (wt. %) 53.9 54.2 H (wt. %) 1.4 1.4 Cl (wt. %) 31.8 30.7 O (wt. %) 9.1 9.5 Ir(III):Ir(IV) (by ESR ≥99.9%:≤0.1% ≥99.9%:≤0.1% spectroscopy)