Method for the preparation of a solution of rhodium 2-ethylhexanoate, comprising the steps a) preparing an aqueous solution of an alkali salt of 2-ethylhexanoate by adding 2-ethylhexanoic acid to an aqueous alkali hydroxide solution at room temperature in a first reaction vessel, wherein the molar ratio of 2-ethylhexanoic acid to alkali hydroxide is 1.0:1.0 to 1.1:1.0 (mol/mol); b) providing a rhodium precursor selected from rhodium chloride hydrate RhCl 3 ∗ xH 2 O, rhodium chloride solution H 3 [RhCl 6] ∗ (H 2 O) n, and rhodium nitrate solution Rh(NO 3) 3 ∗ (H 2 O) n, as well as mixtures thereof, in a second reaction vessel; c) mixing the aqueous solution of the alkali salt of 2-ethylhexanoate and the aqueous solution of the rhodium precursor at an internal temperature of the reaction vessel of 20-30 °C to obtain a mixture; d) heating of the mixture from step c) - to an internal temperature of the reaction vessel of 80-90 °C, if the Rh precursor is Rh chloride solution or Rh chloride hydrate, or - to an internal temperature of 80-100 °C, if the Rh precursor is Rh nitrate, to obtain a suspension; e) cooling of the suspension from step d) while stirring - to an internal temperature of 40-50 °C, if the Rh precursor is Rh chloride solution or Rh chloride hydrate, or - to an internal temperature of 55-65 °C, if the Rh precursor is Rh nitrate f) adding an alcohol that is immiscible with water, a carboxylic acid that is immiscible with water, or a mixture thereof, while stirring, g) stirring for 30 min. to 3 h, i) draining off the bottom, aqueous phase, j) washing the top, product-containing organic phase with aqueous mineral acid, if the Rh precursor in the step contains rhodium chloride hydrate RhCl 3 ∗ xH 2 O and/or rhodium chloride solution H 3 [RhCl 6] ∗ (H 2 O) n. a) preparing an aqueous solution of an alkali salt of 2-ethylhexanoate by adding 2-ethylhexanoic acid to an aqueous alkali hydroxide solution at room temperature in a first reaction vessel, wherein the molar ratio of 2-ethylhexanoic acid to alkali hydroxide is 1.0:1.0 to 1.1:1.0 (mol/mol); b) providing a rhodium precursor selected from rhodium chloride hydrate RhCl 3 ∗ xH 2 O, rhodium chloride solution H 3 [RhCl 6] ∗ (H 2 O) n, and rhodium nitrate solution Rh(NO 3) 3 ∗ (H 2 O) n, as well as mixtures thereof, in a second reaction vessel; c) mixing the aqueous solution of the alkali salt of 2-ethylhexanoate and the aqueous solution of the rhodium precursor at an internal temperature of the reaction vessel of 20-30 °C to obtain a mixture; d) heating of the mixture from step c) - to an internal temperature of the reaction vessel of 80-90 °C, if the Rh precursor is Rh chloride solution or Rh chloride hydrate, or - to an internal temperature of 80-100 °C, if the Rh precursor is Rh nitrate, to obtain a suspension; - to an internal temperature of the reaction vessel of 80-90 °C, if the Rh precursor is Rh chloride solution or Rh chloride hydrate, or - to an internal temperature of 80-100 °C, if the Rh precursor is Rh nitrate, e) cooling of the suspension from step d) while stirring - to an internal temperature of 40-50 °C, if the Rh precursor is Rh chloride solution or Rh chloride hydrate, or - to an internal temperature of 55-65 °C, if the Rh precursor is Rh nitrate - to an internal temperature of 40-50 °C, if the Rh precursor is Rh chloride solution or Rh chloride hydrate, or - to an internal temperature of 55-65 °C, if the Rh precursor is Rh nitrate f) adding an alcohol that is immiscible with water, a carboxylic acid that is immiscible with water, or a mixture thereof, while stirring, g) stirring for 30 min. to 3 h, i) draining off the bottom, aqueous phase, j) washing the top, product-containing organic phase with aqueous mineral acid, if the Rh precursor in the step contains rhodium chloride hydrate RhCl 3 ∗ xH 2 O and/or rhodium chloride solution H 3 [RhCl 6] ∗ (H 2 O) n.