Biodegradable chelating agent and preparation method thereof

The invention provides a biodegradable chelating agent and a preparation method thereof. The preparation method is characterized by comprising the following steps: 1) firstly, weighing chloroacetic acid and water, then slowly dropwise adding liquid caustic soda while controlling the temperature not to exceed 45 DEG C, and reacting to prepare sodium chloroacetate; (2) preparing a disodium L-glutamate solution by reacting metered deionized water, L-glutamic acid and caustic soda liquid, adding a catalyst, and then heating to 85 DEG C; (3) simultaneously adding the material in the step (1) and the prepared liquid caustic soda into the mixture in the step (2), controlling the dripping speed of the material and the prepared liquid caustic soda and the pH value of a reaction system, and controlling the pH value to be 9.5-10.5; and 4) after the dropwise addition is finished, reacting for 1 hour, then heating to 95 DEG C, continuously reacting for 3 hours, and after the reaction is finished, cooling to room temperature to directly obtain a finished product of the GLDA green chelating agent solution. The operation is simple, the process is stable, the product quality is high, the performance is good, and the biodegradable chelating agent has huge application prospects and market economic benefits.