Denki Kagaku Kogyo Kabushiki Kaisha

Iwao Kibayashi

Hideaki Yamada

Yoshiaki Ishimatsu

Masahisa Ikemi

Chiyuki Fujii

Teruzo Miyoshi

Tetsuya Ando

Yoshio Kosai

Mitsukuni Ayabe

Tunehiko Shimizui

Hideki Hirano

Haruo Gomi

Masaaki Kato

Hideyuki Udagawa

Noriaki Koizumi

A precursor of phenylalanine containing as a major component 5-benzylhydantoin is prepared by reacting, in an aqueous medium, a bisulfite addition salt of phenylacetaldehyde with cyanide and carbonate ions, each being in a molar ratio of equimol or more to said bisulfite addition salt and ammonium ion in a molar ratio of 2 or more to said carbonate ion. The thus prepared precursor of phenylalanine may be converted into phenylalanine by a hydrolysis under a basic or acidic condition.

Process for the preparation of hydantoin precursor of phenylalanine

Disclosed is a process for preparing L-threonine which comprises causing D-threonine-aldolase, or D-threonine-aldolase and L-allothreonine-aldolase to act on a solution containing at least DL-threonine thereby obtaining L-threonine from a mixture containing at least DL-threonine.

Process for preparing L-threonine

A cement composition is provided which comprises a cement, and 0.1 to 2.5% by weight, based on the weight of said cement, of a dextrin having a cold-water solubility of from 10 to 80% by weight. The cement composition of the invention suppresses heat of hydration, so that the cement mortar or concrete do not crack due to the heat of hydration.

Cement composition containing dextrin

A method of preparing citraconic acid and derivatives thereof comprising reacting methylsuccinic acid and derivatives thereof (such as an acid halide, an acid anhydride, a monoester and a diester) with chlorine in the absence of or in the presence of a catalyst at a temperature ranging from about 100.degree. to 500.degree.C.

Method for preparation of citraconic acid and derivatives thereof

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Machida, Japan

Iwao Kibayashi