PURPOSE: To produce high-purity L,L-ethylenediaminedisuccinic acid (EDDS) excellent in biodegradability in high yield in a process good in reproducibility by using an industrially readily available glyoxal and L-aspartic acid as raw materials.
CONSTITUTION: This method for producing an alkali metallic salt of L,L-EDDS is to condense one molecule of glyoxal with 2 molecules of L-aspartic acid under neutral to alkaline conditions, produce a Schiff base and then reduce the resultant Schiff base according to catalytic hydrogenation in the presence of a catalyst. Furthermore, the method for producing the L,L-EDDS is to similarly produce the Schiff base, subsequently reduce the Schiff base according to the catalytic hydrogenation, then deposit the resultant compound with a mineral acid and crystallize the compound or produce the Schiff base, then reduce the Schiff base with a metallic hydroxide and subsequently deposit the compound with the mineral acid and crystallize the compound.
KOIDE SATOSHI
TAKAYANAGI YASUYUKI
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