Process for preparing trans-chrysanthemic acid
AssigneeSumitomo Chemical Company, Limited
InventorsGohu Suzukamo, Masami Fukao, Tsuneyuki Nagase, Horosuke Toshioka
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Abstract
A process for preparing trans-chrysanthemic acid which comprises reacting a mixture of alkyl trans-chrysanthemate and alkyl cis-chrysanthemate with an equimolar amount or less of an alkali with respect to the trans-isomer in the presence of water or an alcohol to hydrolyze the trans-isomer predominantly and separating the hydrolyzed trans-isomer from the unreacted cis-isomer.
Claims6
A process for preparing an enriched trans-chrysanthemic acid from a mixture of alkyl trans-chrysanthemate and alkyl cis-chrysanthemate which comprises reacting said mixture with an alkali metal hydroxide or an alkali metal alcoholate in an amount of from 0.5 to 1 mole based on 1 mole of the trans-isomer in the presence of water or an alcohol at a temperature of from 10.degree. to 150.degree. C to hydrolyze the trans-isomer predominantly and separating the hydrolyzed product from the unreacted alkyl chrysanthemate to obtain an enriched trans-chrysanthemic acid.
A process for preparing an enriched trans-chrysanthemic acid from a mixture of alkyl trans-chrysanthemate and alkyl cis-chrysanthemate which comprises the step of (1) reacting said mixture with an alkali metal hydroxide or an alkali metal alcoholate in an amount of from 0.5 to 1 mole based on 1 mole of the trans-isomer at a temperature of from 10.degree. to 150.degree. C to hydrolyze the trans-isomer predominantly, (2) separating the hydrolyzed product from the unreacted alkyl chrysanthemate to obtain an enriched trans-chrysanthemic acid and (3) epimerizing the alkyl cis-chrysanthemate in the unreacted alkyl chrysanthemate and recycling the epimerized product to step (1).
Dependencies are inferred from the claim text.