Method for isolating polymethyl alkanoic acids and disposal of the resulting wastes

摘要

A process for isolating polymethylolalkanoic acids or monomethylolalkanoic acids of the formula (I) where R are identical or different and are each a substituted or unsubstituted hydrocarbon radical or a methylol group, which have been prepared from the corresponding polymethylolalkanals or monomethylolalkanals of the formula (II) where R are as defined above, by oxidation using an aqueous solution of hydrogen peroxide comprises a) carrying out a crystallization followed by a liquid/solid separation (B) to give the acid as first crystallized material (2a) plus mother liquor (3), b) producing further crystallized material (2b) in the mother liquor (3) and separating the resulting mother liquor (3) from the further crystallized material (2b) in a further solid/liquid separation (C), and c) disposing of the resulting mother liquor (3) which has been depleted in the acid.