A process for separating inorganic and organometallic by-products from a mixture comprising at least one organometallic transition metal compound as product and at least one organometallic by-product and at least one inorganic by-product as by-products, which comprises the steps
- A) admixing the mixture comprising the product, the organometallic by-product and the inorganic by-product with a mixture comprising at least one polar organic extractant and water and separating off the undissolved residue,
- B) washing the residue from step A) with a nonpolar organic extractant or a mixture comprising at least one nonpolar organic extractant and at least one aprotic polar organic solvent and
- C) drying the residue which has been washed in step B) and comprises the organometallic transition metal compound.