Mitsubishi Gas Chemical Company, Inc.

Yukiya Ibi

Tatsuyuki Kumano

Shinichi Nagao

Natsumi Wakita

Kuniaki Arasuna

Emi Noguchi

The object is to prevent deterioration and loss of dicyanobenzene in producing dicyanobenzene by ammoxidation of xylene to thereby achieve industrial and economical advantage in producing of dicyanobenzene. The method for producing dicyanobenzene of the present invention includes: contacting a xylene-ammoxidation reaction gas containing dicyanobenzene in ammoxidation of xylene with an organic solvent so as to obtain a dicyanobenzene-absorbing solution; contacting the dicyanobenzene-absorbing solution with a basic aqueous solution containing a salt such as ammonium carbonate so as to extract a water-soluble salt formed by neutralization reaction between carboxylic acid in the dicyanobenzene-absorbing solution and a base in the basic aqueous solution into an aqueous phase; separating the mixture of the dicyanobenzene-absorbing solution and the basic aqueous solution into an organic phase and an aqueous phase; decomposing the salt such as ammonium carbonate contained in the organic phase for separation of the salt from the organic phase; and distilling the organic phase to separate low boiling point compounds contained in the organic phase from the organic phase so as to obtain dicyanobenzene.

Method and apparatus for producing dicyanobenzene

Provided is a method for stably and economically producing xylylenediamine with a high yield and long catalyst service life by hydrogenating dicyanobenzene that is obtained by ammoxidating xylene. By bringing an aqueous basic solution into contact with a dicyanobenzene-absorbed liquid, which is obtained by bringing an ammoxidation reaction gas into contact with an organic solvent, under specified temperature conditions, and subjecting a base and a carboxylic acid in the dicyanobenzene-absorbed liquid to a neutralization reaction so as to form an aqueous phase that contains a water-soluble salt, and then subjecting an organic phase and the aqueous phase to liquid-liquid separation so as to remove the aqueous phase, it is possible to remove the carboxylic acid contained in the dicyanobenzene-absorbed liquid with high selectivity while inhibiting loss of the dicyanobenzene. By subjecting the raw material dicyanobenzene, which is obtained by separating low boiling point compounds from the post liquid-liquid separation organic phase by distillation under reduced pressure, to hydrogenation, xylylenediamine is produced with a high yield and the service life of the hydrogenation catalyst is extended.

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Kurashiki, Japan

Yukiya Ibi