Mitsui Toatsu Chemicals, Incorporated

Ryoichi Taneda

Hiroyuki Itoh

Yoshitsugu Kono

Usaji Takaki

Tsugio Watanabe

Hiroshi Ichiki

Disclosed herein is a crystallization apparatus for use in the crystallization of L-.alpha.-aspartyl-L-phenylalanine methyl ester. The stirring blade of the crystallization apparatus is composed of a band plate member for sweeping the bottom of a vessel and rod- or band plate-members arranged thereon and extending substantially vertically and horizontally.

Process for the crystallizing L-.alpha.-aspartyl-L-phenylalanine methyl

There is here disclosed a method for obtaining high-purity cinnamic acid containing less metals from crude cinnamic acid containing a metallic catalyst which is a mixture prepared by the synthetic reaction of a cinnamic acid ester. A disclosed purifying means is the combination of alkali hydrolysis, active carbon adsorption, solvent extraction and precipitation with an acid.

Method for obtaining high-purity cinnamic acid

A process for purifying tryptophan is disclosed. In the process of the present invention, tryptophan is recrystallized in water-containing acetic acid. By the process of the present invention, tryptophan with high purity may be obtained with high yield without condensation or neutralization.

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Omuta, Japan

Ryoichi Taneda