Japan Synthetic Rubber Co., Ltd.

Masao Kariya

Minoru Matsubara

Toshio Omori

Norihiko Adachi

Tohru Masukawa

Tohru Kodama

Miki Fukuta

A process for producing cis-4,5-dihydro-4,5-dihydroxyphthalic acid which comprises producing cis-4,5-dihydro-4,5-dihydroxyphthalic acid and/or a salt thereof from phthalic acid and/or a salt thereof using a microorganism whose activity to decompose cis-4,5-dihydro-4,5-dihydroxyphthalic acid and/or a salt thereof has disappeared or diminished, acidifying the product system unless it is acidic, and then extracting therefrom cis-4,5-dihydro-4,5-dihydroxyphthalic acid with such an organic solvent that it is miscible with water in any proportion and the mixture of the organic solvent with water can be separated into two layers upon adding a salt thereto, in the presence of a salt, or with an alcohol having 4 carbon atoms. The process enables one to produce cis-4,5-dihydro-4,5-dihydroxyphthalic acid from phthalic acid and/or its salt in a high yield.

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Toride, Japan

Masao Kariya