Kao Corporation

Masaji Yamanishi

Kohshiro Sotoya

Makoto Kubo

Kazuhiko Okabe

Masanobu Tanigaki

Hajime Hirota

A surface active agent comprising a specific type of secondary amidoamino acid or ammonium ion or triethanolammonium salt thereof, ##STR1## as a major component, and not more than 0.2 mole of an inorganic salt per 100 gm of said secondary amidoamino acid or 100 gm of a salt thereof as converted to the acid type secondary amidoamino acid. The surface active agent can be prepared by subjecting the alkali metal salt of secondary amidoamino acid, usually containing a great amount of impurities such as sodium chloride, to electrodialysis. It has excellent compatibility with various additives such as water-soluble polymer due to its low ionic strength and yet exhibits a good low-temperature stability when made into an aqueous solution owing to its low Krafft point.

Surface active secondary amidoamino acid or salt compounds

A novel process for preparing an alkanolammonium salt or ammonium salt of an amino acid surface active agent or an acylated amino acid surface active agent. In the process, an alkali metal salt of an amino acid surface active agent or acylated amino acid surface active agent is subjected to electrodialysis in the presence of a mineral acid salt of an alkanolamine or ammonia, or a mixture of an alkanolamine or ammonia and a mineral acid. By-products which are produced during the preparation of the above surface active agents can be mostly removed to outside during the electrodialysis and are thus purified conveniently.

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Wakayama, Japan

Masaji Yamanishi