PEP Review 83-1-3
Published: November 1983
Aminocarboxylic acids and their alkali metal salts are widely used as chelating agents. Among these, nitrilotriacetic acid (mainly as its trisodium salt monohydrate) is particularly effective as a detergent builder and in various industrial and institutional applications such as water treatment, textile processing, and surface cleansing. However, its growth in the United States has been retarded by a long history (dating back to the late sixties) of doubts about its safety.
In this review we examine the production economics of trisodium nitriloacetate monohydrate. The manufacturing processes used consist of a three-stage reaction system. Hexamethylenetetramine is first made from NH3 and formaldehyde for conversion to nitrotriacetonitrile by further reaction with HCN and formaldehyde. The final product is made by the saponification of the nitrile with aqueous NaOH.