KR810001553B1 - Process for recovering and regeneration of rodium catalyst - Google Patents

Abstract

This method describes the process of recovering and regeneration of Rodium compd. used as catalyst in the chem. reaction. Thus, in recovery of Rodium from the reaction residue, the reaction residue is heated and decompd. after adding of inorg. acids such as H2SO4 or HNO3 or the mixt. of these acids and recovered the Rodium compd. by using alkali metal hydroxide such as NaOH or KOH, or NH4OH.

Description

Recovery and Regeneration of Rhodium Compounds Used as Catalysts in Chemical Reactions

The present invention is a method of separating the final product in the reaction using a rhodium compound as a catalyst and recovering the rhodium from the remaining two liquids to be used for the reaction again.

Rhodium compound catalysts which are widely used in various reactions are one of the platinum group metal compounds. These platinum group metal compounds are limited resources and expensive precious metals, making the recovery and regeneration of catalysts used in the chemical industry essential. In general, the following considerations should be taken into account when the catalyst is degenerated.

First, if it does not serve as a catalyst,

Second, there is no need to be given in any particular form, it can be divided into the case of participating in the reaction by changing to the activated form during the reaction of the various types of compounds in the reactor.

However, even in the second case, the catalyst loss caused by the accelerated use ultimately needs to be recycled in a specific form as in the first case.

Since the recovery and regeneration methods of rhodium compounds known to date are different from each reaction condition and the final product of the reactants of the reaction, a method suitable for each reaction can not be recovered and regenerated using only one method. There was a drawback to using it.

It is a feature of the present invention to overcome this disadvantage that the rhodium compounds used in most chemical reactions can be applied to recovery and regeneration in a certain form, and the recovery rate is also high. More specifically, the method is as follows. After separating the final product and removing the solvent by using an evaporator and a vacuum pump to remove the solvent, and refluxed to adjust the pH to alkali metal hydroxides such as sodium hydroxide, potassium hydroxide or ammonium hydroxide, and left at room temperature for one day to rhodium compound The sediment contained subsides. After filtering this, the cake was dried in a vacuum oven for one day, and then placed in a decomposition flask to decompose organic matter with an appropriate amount of inorganic acid. In this case, the inorganic acid refers to sulfuric acid and nitric acid, but each may be used alone, or two acids may be mixed and used. The organically decomposed turbidity is transferred to a quartz crucible and alkali metal hydroxide or ammonium hydroxide is added. Insert until it no longer reacts and heat with gas bunnies. The solution in the crucible is heated to a clear yellow color, cooled to room temperature, dissolved in distilled water, transferred to a beaker, and then added with alkali metal hydroxide or ammonium hydroxide. When you add it, an orange precipitate begins to form. Add alkali metal hydroxide or ammonium hydroxide until no orange precipitates anymore, leave for one day, and filter. Hydrochloric acid is added to the filtered precipitate to completely dissolve it and then dried in a water bath until no smell of hydrochloric acid is obtained to obtain a hydrate of rhodium chloride (RhC1 ₃ H ₂ O).

The following examples will illustrate, but are not limited to, the present invention in more detail.

EXAMPLE

In the reaction where the rhodium compound was used as a catalyst, 100 g of the remaining liquid (the rhodium contained 40 mg (0.151 m mole) in the case of hydrate of rhodium chloride) after evaporation of the solvent by an evaporator was dissolved in sodium hydroxide. The solution is adjusted to pH 6.5, refluxed and left to filter at room temperature for one day. 20 sulfuric acid was added to the filtered cake and nitric acid was added while heating to completely decompose the organic matter. Transfer the solution to a quartz crucible, add sodium hydroxide, heat and cool. Dissolve this in distilled water, add sodium hydroxide, filter the precipitate, and add hydrochloric acid to dissolve the precipitate. Hydrochloric acid was blown into the water bath and 39 mg (0.148 m mole) of rhodium chloride trihydrate was obtained. The resulting recovery of rhodium chloride trihydrate (RhC1 _3. 3H ₂ O) was 97.5%.

Claims (1)

In recovering rhodium from the reaction residue, an inorganic acid is added to the reaction residue, followed by heating and decomposition, and recovering the rhodium compound in a high yield using an alkali metal hydroxide or ammonium hydroxide as a catalyst. Recovery and Regeneration Method of Rhodium Compound Used. Herein, inorganic acid refers to sulfuric acid, nitric acid or a mixture of two acids, and alkali metal hydroxide refers to sodium hydroxide and potassium hydroxide.