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US 4,058,560 AGranted
Chemical process
AssigneeEthyl Corporation
InventorThomas J. Walter
Life of this patent
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AssigneeEthyl Corporation
InventorThomas J. Walter
Estimating the term…
It is disclosed that the production and recovery of water soluble carboxymethyloxy succinic acid salt from zinc or alkaline earth metal carboxymethyloxy succinic acid salt is enhanced by adding the zinc or alkaline earth metal salt to a carbonate which forms therewith a water soluble carboxymethyloxy succinic acid salt. The treating process, performed in an aqueous system, produces a zinc or alkaline earth metal carbonate precipitiate which is readily and quickly filtered providing a significant improvement in filterability over that experienced when the starting carbonate is added to the alkaline earth metal carboxymethyloxy succinate. Preferably the addition is progressive; that is, the zinc or alkaline earth metal carboxymethyloxy succinate is added to the carbonate gradually so that for the most part the carbonate is present in excess over the other reactant.
In the method of producing the trialkali metal salt of carboxymethyloxy succinic acid by reacting in an aqueous medium, maleic acid and glycolic acid under basic conditions in the presence of zinc or alkaline earth metal ions to produce a zinc or alkaline earth metal salt of carboxymethyloxy succinic acid and treating said zinc or alkaline earth metal salt with alkali metal carbonate thereby forming a reaction mixture containing the trialkali metal salt and zinc or alkaline earth metal carbonate, the improvement of gradually adding zinc or alkaline earth metal salt of carboxymethyloxy succinic acid to the alkali metal carbonate.
Dependencies are inferred from the claim text.