METHOD OF PREPARING SOLID TRISODIUM SALT OF NITRILOTRIMETHYL PHOSPHONIC ACID Russian patent published in 2001 - IPC

FIELD: preparation of crystalline sodium salts of nitrilotrimethyl phosphonic acid, more particularly salt deposition inhibitors in heat power industry, drilling mud components in oil production, purification of wines in food industry, complexing agents in detergent production. SUBSTANCE: method is carried out as follows: nitrilotrimethyl phosphonic acid or disodium salt thereof is neutralized with sodium hydroxide to pH of 5.1-5.6; in this case, concentration of reaction mixture /solution of acid or salt thereof plus alkali or solution thereof as calculated for nitrilotrimethyl acid varies from 25 to 40 wt %, and isolation of desired product is carried out in aqueous methanol medium at reaction mixture to methanol volumetric ratio from 1: 3 to 1:4 followed by filtration and drying of product. When process is carried out with preparation of nitrilotrimethyl phosphonic acid, e.g. by reacting ammonia water, formalin and trivalent phosphorus compounds, nitrilotrimethyl phosphonic acid is first isolated from reaction mixture by crystallization and then dissolved in water and neutralized followed by treatment in methanol. EFFECT: more efficient preparation method. 6 cl, 3 ex, 1 tbl