| abstract |
1354637 Sequestering MONSANTO CO 10 Jan 1972 [11 Jan 1971] 1000/72 Heading C1C [Also in Divisions C2 and D1] As sequestering or " threshold " agents for metal ions (e.g. of Ca, Fe, Co or Cu) in aqueous systems, there are employed compounds of formula wherein R 3 and R 4 are each H, a metal ion or an optionally substituted ammonium ion. Example IV describes calcium sequestration in an aqueous system comprising calcium nitrate, sodium oxalate and sodium hydroxide. |