Mitsubishi Rayon Company, Limited

Nitto Chemical Industry Co., Ltd.

Teturo Nakahama

Kiyobumi Takahashi

Hiroshi Yamamoto

Yasuyuki Takayanagi

Chelating agent and detergent comprising the same

The present invention relates to a biodegradable amino-carboxylic acid chelating agent excellent in biodegradability and for use as a chelating agent, which is in the form of a solid, aqueous solution or slurry excellent in handling ability, wherein the chelating agent comprises a detergent composition having excellent detergency and high biodegradability.

Disclosed is a biodegradable chelating agent which comprises a compound of the following formula &lsqb;1&rsqb; and at least one compound selected from the group consisting of aspartic acid, maleic acid, acrylic acid, malic acid, glycine, glycolic acid, iminodiacetic acid, nitrilotriacetic acid, &agr;-alanine, &agr;-alanine, iminodipropionic acid, fumaric acid, a synthetic starting amino acid and a synthetic intermediate amino acid and a salt thereof in an amount of 8% by weight or less based on the compound of the formula &lsqb;1&rsqb;:

Aspartic acid is reacted with prussic acid and formaldehyde to give an amino-polycarboxylic acid or a salt thereof represented by-the following formula: ##STR1## wherein each of R.sup.1 and R.sup.2 represents a hydrogen atom, an alkali metal or an ammonium group; and each of R.sup.3 and R.sup.4 represents a hydrogen atom or --CH.sub.2 --COOR.sup.1, provided that R.sup.3 and R.sup.4 do not represent a hydrogen atom simultaneously. The amino-polycarboxylic acid which is readily biodegradable and has an excellent chelating ability can be obtained from aspartic acid in a high yield and in a high purity.

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Iwaki, Japan

Teturo Nakahama