Synthesis
Weighed 1.04g of trans-1,2-cyclohexanediamine sulfate product and 2.31g of chloroacetic acid, dissolved in 2.5mL of distilled water. Under the condition of room temperature, add NaOH aqueous solution (5.0mL, 30%) dropwise while stirring, after the dropwise addition, slowly raise the temperature to 70 , keep warm for 2h, then slowly lower the temperature to 50 , control the reaction solution pH=12, keep warm and react for 1h. stop the reaction, cool and let it stand, filter it, dropwise add hydrochloric acid solution (6 mol/L) to the filtrate until the pH=1, stop dropping and continue stirring. 20min, filtration, washing, the resulting product was dried at 105 to obtain trans-1,2-cyclohexanediaminetetraacetic acid crude finished product.
Purification Methods
Dissolve CDTA in aqueous NaOH as its disodium salt, then precipitate it by adding HCl. The free acid is filtered off and boiled with distilled water to remove traces of HCl [Bond & Jones Trans Faraday Soc 55 1310 1959]. Recrystallise it from water and dry it in vacuo.[Beilstein 13 III 10.]
