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AssigneeAjinomoto Co., Inc.
InventorsEizo Kanatani, Ryosuke Yumioka, Shingo Sanada, Yasushi Kawabata
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The present invention aims at providing a convenient method of producing zinc pyrrolidonecarboxylate dihydrate, which is an industrially useful compound, with high optical purity, a higher yield, and better dissolution property. The present invention also provides a convenient method of producing zinc pyrrolidonecarboxylate dihydrate with higher optical purity, a higher yield, and better solution property by adding a zinc salt to an aqueous medium containing a salt of pyrrolidonecarboxylic acid as a starting material and separating a crystal from the aqueous medium at a specific pH.
A method of producing zinc pyrrolidonecarboxylate dihydrate, which comprises the steps of
A method of evaluating a zinc pyrrolidonecarboxylate dihydrate, which comprises a step of measuring light transmittance of a 10 g/dl aqueous solution thereof.
A zinc pyrrolidonecarboxylate dihydrate with an optical purity ranging from 100% to 95%, wherein a light transmittance of a 10 g/dl aqueous solution thereof at a wavelength of 550 nm is within the range of 94 to 100% under an optical path length of 10 mm.
Dependencies are inferred from the claim text.