Ajinomoto Co., Ltd.

Akihiko Yasaki

Shinichi Kishimoto

Takehiko Kataoka

Harutoshi Ohura

Masayoshi Naruse

Toshihisa Kato

Haruo Kawasaki

Yoshinobu Uchida

A process for obtaining dry crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a water content of about 2 wt. % to about 6 wt. % based on the weight of the wet crystals is disclosed. This process comprises exposing wet crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester, having a water content not greater than 50 wt. % based on the weight of the wet crystals and obtained by the crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester from an unagitated solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester, to a flow of air having a temperature of 80.degree. C. to 200.degree. C.

Process for preparing dry crystals of the methyl ester of

Granules of .alpha.-L-aspartyl-L-phenylalanine methyl ester, containing IB crystals of the ester and having a grain size of from 100 to 1400 .mu.m have improved water solubility.

Granules of .alpha.-L-aspartyl-L-phenylalanine methyl ester

A method for the solid-liquid separation of a suspension of .alpha.-L-aspartyl-L-phenylalanine methyl ester (.alpha.-APM) or its hydrochloride salt (.alpha.-APM.HCl), wherein an aqueous suspension of .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrochloride salt is subjected to continuous separation by vacuum filtration.

Method of preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester or

The present invention discloses a method to separate each component from a mixed solution of organic solvents obtained during the production of .alpha.-L-aspartyl-L-phenylalanine methyl ester, which is useful as a sweetener, namely, a mixed solution of acetic acid and toluene or a mixed solution of acetic acid, toluene and formic acid, recovering each component with a high recovery ratio with as small number of operations as possible. The method rationalizes the process and is highly valuable in practical use. When each component is separated and recovered from a mixed solution containing acetic acid and toluene as the main components, acetic acid and toluene are separated by azeotropic distillation using water as an azeotropic solvent, and when each component is separated and recovered from a mixed solution containing acetic acid, toluene and formic acid as the main components, (a) the mixed solution is distilled and formic acid is recovered from the top of the column and a mixed solution of acetic acid and toluene is recovered from the bottom of the column; and (b) the mixed solution obtained from the bottom is distilled by using water as an azeotropic solvent and toluene is recovered from the top of the column and acetic acid is recovered from the bottom of the column.

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Kawasaki, Japan

Akihiko Yasaki