| abstract |
The present invention relates to a method for preparing a complexing agent, the method comprising the following steps: (a) providing a nitrile according to formula (la) or (lb) In which M is selected from alkali metals and hydrogen and combinations thereof, (b) saponifying to a total alkali amount of 2.5 mol to 2.9 mol of alkali metal hydroxide per mol of nitrile according to formula (Ia) or (Ib), respectively, and to a pH value in the range of 9.5 to 11.5 at the end of step (b), respectively. step, (c) adding an alkali metal hydroxide in an amount such that the total alkali content is, respectively, from 2.9 mol to 3.15 mol per mol of nitrile according to Formula (Ia) or (Ib), and (d) allowing further conversions. |