Basf Aktiengesellschaft

Walter Boehm

Gerhard Hamprecht

Karl-Heinz Koenig

Gerd Husslein

Manfred Gaeng

A process for the preparation of 2,4-dichloro- or 2-methyl-4-chlorophenoxyacetic acid or .alpha.-2,4-dichloro- or .alpha.-2-methyl-4-chlorophenoxypropionic acid by reacting phenoxyacetic or 2-methylphenoxyacetic acid or .alpha.-phenoxypropionic or .alpha.-2-methylphenoxypropionic acid with chlorine in water, wherein phenoxyacetic acid or phenoxypropionic acid is precipitated from an aqueous solution thereof, chlorine gas is passed into the resulting suspension of phenoxyacetic or 2-methylphenoxyacetic acid or .alpha.-phenoxypropionic or .alpha.-2-methylphenoxypropionic acid in water at from 30.degree. to 70.degree. C. at a rate not exceeding the rate at which it is consumed in the suspension, until from 100 to 110% of the theoretically required amount of chlorine gas has been taken up by the suspension, and the 2,4-dichloro- or 2-methyl-4-chloro-phenoxyacetic acid or .alpha.-2,4-dichloro- or .alpha.-2-methyl-4-chloro-phenoxypropionic acid is isolated from the suspension.

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Kirchheim, Germany

Walter Boehm