| 摘要 |
PURPOSE:To separate the titled compound which is a raw material for producing various organic chemicals selectively by using the difference in pKa between the cis- and the trans-isomers, by converting a mixture of the cis- and the trans- isomers of cinnamic acid and a derivative thereof into a metal salt, and reacting the metal salt with a specific amount of an acid. CONSTITUTION:A mixture of the cis- and the trans-isomers of cinnamic acid and a derivative expressed by formula I (R1 and R2 are H or lower alkoxyl) is converted into an alkali metal or alkaline earth metal salt in an aqueous solution. If the mixture is scarcely dissolved, the dissolution is accelerated by heating. A mineral acid in an amount of gram equivalents corresponding to the trans-isomer content is added to the resultant solution to deposit and recover only the trans- isomer from the aqueous solution. An acid is then added to adjust the filtrate to about 1.0pH, and crystals of the cis-isomer are deposited.
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