METHOD OF PRODUCING MIXTURES OF CHELATING AGENTS Russian patent published in 2019 - IPC C07C227/18 C07C229/16 C09K8/35 C11D3/33 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a chelating agent according to general formula (I) R¹-C(COOX¹)-N(CH₂COOX¹)₂ (I), which contains at least one compound of general formulas (IIIa) - (IIIb) R₁-CH(COOX₁)-N(CH₂COOX₁)(CH₂CONH₂) (III a) R-CH(COOX₁)-N(CH₂CONH₂)₂ (III b), where R¹ is selected from C₁-C₄-alkyl, X¹ is (M_xH_1-x), wherein M is selected from an alkali metal, x is in range from 0.6 to 1. Method comprises the following steps: (a) providing solid substance, suspension or solution of compound according to general formula (IIa) R¹-CH(COOX²)-N(CH₂CN)₂ (IIa), where X² is (M_yH_1-y), wherein M is selected from an alkali metal, y is in range from 0 to 1, (b) contacting said solid substance or suspension or solution with an aqueous solution of an alkali metal hydroxide, wherein molar ratio of alkali metal ions to nitrile groups ranges from 0.7:1 to 0.9:1, and (c) reacting said compound according to general formula (IIa) with said alkali metal hydroxide.

EFFECT: disclosed method provides chelating agents and can be made in devices made from or containing parts made from stainless steel, wherein said parts are exposed to reaction mixture of saponification step.

6 cl, 1 tbl, 1 ex