Ajinomoto Co., Ltd.

Harutoshi Ohura

Shinichi Kishimoto

Takehiko Kataoka

Akihiko Yasaki

Tadashi Takemoto

Masayoshi Naruse

Haruo Kawasaki

Yoshinobu Uchida

Makoto Nishikawa

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

In producing granules of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a particle size of falling within a determined particle size range by compaction granulation, formation of fine powdery .alpha.-APM is prevented by breaking the compacted .alpha.-APM so that the one-pass yield of the granules is elevated and the sieving efficiency is elevated. In a method of preparing granules of .alpha.-L-aspartyl-L-phenylalanine methyl ester by compaction granulation of the ester singly or along with a vehicle of not more than the same amount of the ester, after the compaction or after having roughly broken the compacted material, the material is broken down so as to pass through a screen or perforated plate having pores with a diameter falling within the range of from 1 mm to 10 mm and then further broken and classified.

Method of preparing granules of dipeptide

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.

Distillation method of separating organic solvents

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Yokkaichi, Japan

Harutoshi Ohura