Process for preparation of metal chelates of aminopolycarboxylic acid compounds

Claim 1

AN IMPROVED METHOD FOR PRODUCING METAL CHELATES OF AMONIOPOLYCARBOXYLIC ACID COMPOUNDS WHICH CONSISTS ESSENTIALLY OF (1) MIXING TOGETHER AND AGITATING AN UP TO ABOUT 0.25 MOLAR AQUEOUS SOLUTION OF A SALT OF A CHELATABLE METAL AND A SULFONIC ACID CATION EXCHANGE RESIN TO EXCHANGE ON SAID RESIN THE CHELATABLE METAL CATION, (2) MIXING IN A BATCH PROCESS AT TEMPERATURE UP TO 100*C. SAID CHELATABLE METAL BEARING CATION EXCHANGE RESIN WITH AN AMINOPOLYCARBOXYLIC ACID CHELATING AGENT IN AN AMOUNT SUBSTANTIALLY STOICHIOMETRIC WITH THE AMOUNT OF CHALATABLE METAL SALT EMPLOYED IN AN AQUEOUS SOLUTION CONTAINING AT LEAST 10 PERCENT BY WEIGHT OF THE CHELATING AGENT FOR ABOUT FROM 1 TO 4 HOURS TO PRODUCE A METAL CHELATE OF SAID AMINOPOLYCARBOXYLIC ACID COMPOUND, AND (3) SEPARATING THE RESIN RETAINING SAID CHELATE FROM THE REACTION MIXTURE AND WASHING THE RESIN WITH WATER TO ELUTE THE DESIRED METAL CHELATE OF AMINOPOLYCARBOXYLIC ACID COMPOUND THEREFROM AND TO RECOVER SAME IN THE AQUEOUS EFFLUENT.