Process for the preparation of 2,4-dichloro-5-fluorobenzonitrile and 2,6-dichloro-3-fluorobenzonitrile
AssigneeBayer Aktiengesellschaft
InventorsFerdinand Hagedorn, Helmut Fiege, Reinhard Lantzsch
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Abstract
A mixture of 2,4-dichloro-5-fluorotoluene and 2,6-dichloro-3-fluorotoluene which cannot be separated in an economically efficient manner and can be reacted individually to give the corresponding benzonitriles is subjected according to the invention to ammoxidation in the form of this mixture and then separated at the stage of the benzonitriles by methods known to the person skilled in the art.
Claims8
A process for the preparation of 2,4-dichloro-5-fluorobenzonitrile and 2,6-dichloro-3-fluorobenzonitrile, in which a mixture of 2,4-dichloro-5-fluorotoluene and 2,6-dichloro-3-fluorotoluene is reacted with ammonia, air and steam in a molar ratio of dichloro-fluorotoluene:ammonia:air:steam=1:1-3:7.5-15:0-10 in the gas phase at a temperature of 350.degree. to 550.degree. C. on an ammoxidation catalyst to give a product mixture of said nitriles.
Dependencies are inferred from the claim text.