Patent ID: 6107518
Filing Date: 2000-08-22
Classification: C07C,D21C

Abstract:
Process for the preparation of iminodisuccinic acid alkali metal salts, wherein maleic anhydride (MA), alkali metal hydroxide (MeOH), ammonia (NH.sub.3) and water are reacted in a molar ratio of MA:MeOH:NH.sub.3 :H.sub.2 O=2:0.1-4:1.1-6:5-30 at temperatures of 70-170.degree. C., under pressures of 1-80 bar over reaction times of 0.1-100 h, ammonia and water are distilled off from the reaction mixture at temperatures of 50-170.degree. C. under pressures of 0.1-50 bar in the course of 0.1-50 h, with the addition of water and 0-4 mol of MeOH per 2 mol of MA originally employed, and after the distillation water is added in an amount such that the solution formed contains a solids content of 5-60%, based on the total weight of the solution.