METHOD OF PRODUCING TRI-ALKALINE SALTS OF METHYLGLYCINE-N,N-DIACETIC ACID WITH NEGLIGIBLE CONTENT OF BY-PRODUCTS Russian patent published in 2010 - IPC C07C227/26 C07C229/16 

FIELD: chemistry.

SUBSTANCE: method involves the following stages: (a) mixing methylglycine nitrile diacetonitrile with water alkali at temperature ≤30°C; (b) a reaction taking place in aqueous alkaline suspension of methylglycine nitrile diacetonitrile at temperature between 10 and 30°C for 0.1-10 hours, which is accompanied by formation of a solution; (c) a reaction taking place in the solution obtained at step (b) at temperature between 30 and 40°C for 0.1-10 hours; (e) if necessary, a reaction is carried out in the solution obtained at step (c) at temperature between 110 and 200°C for 5-60 minutes under pressure corresponding the said temperature; (f) hydrolysis and separation of ammonia from the solution obtained at step (c) or (e) through stripping at temperature between 90 and 105°C with addition of water in order to keep salt concentration at a level lower than 45 wt % for removal of ammonia formed in the process.

EFFECT: method enables to obtain tri-alkaline salt of methylglycine-N,N-diacetic acid with negligible content of by-products.

4 cl, 4 ex