Method for producing dihydroxyindoles
AssigneeKao Corporation
InventorsNorihiro Ito, Masayoshi Nakamoto
Life of this patent
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Abstract
A method for producing dihydroxyindoles includes: a step 1 of obtaining an aqueous first solution including DHIs obtained by causing DOPAs to react with hexacyanoferrate(III); a step 2 of obtaining an oleaginous second solution in which DHIs are extracted in an extraction solvent by mixing the first solution obtained in the step 1 with the extraction solvent; and a step 3 of obtaining an aqueous third solution by evaporating the extraction solvent from a mixture of the second solution obtained in the step 2 and water. The extraction of DHIs in the step 2 is performed in a tank A. After the second solution is discharged from the tank A, the second solution is supplied to a tank B, and then the step 3 is performed in the tank B.
Claims15
A method for producing dihydroxyindoles, comprising:
- a step 1 of obtaining an aqueous first solution including dihydroxyindoles obtained by causing at least a material selected from the group consisting of 3-(3,4-dihydroxyphenyl)alanine and a derivative of 3-(3,4-dihydroxyphenyl)alanine to react with hexacyanoferrate(III);
- a step 2 of obtaining an oleaginous second solution in which the dihydroxyindoles are extracted in an extraction solvent by mixing the first solution obtained in the step 1 with the extraction solvent;
- and
- a step 3 of obtaining an aqueous third solution by evaporating the extraction solvent from a mixture of the second solution obtained in the step 2 and water, wherein
- the dihydroxyindoles are extracted in a tank A in the step 2, the second solution is discharged from the tank A, the second solution is supplied to a tank B, and then the step 3 is performed in the tank B.
Dependencies are inferred from the claim text.