US 2013/0296609 A1Published application

Method for producing xylylenediamine

AssigneeMitsubishi Gas Chemical Company, Inc.

InventorsTatsuyuki Kumano, Yukiya Ibi, Kuniaki Arasuna, Shinichi Nagao

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Abstract

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.

Claims11

Dependent claims

A method for producing xylylenediamine, comprising:

(i) bringing a xylene-ammoxidation reaction gas comprising a dicyanobenzene, which is obtained by ammoxidizing an xylene via an ammoxidation reaction, into direct contact with an organic solvent, thereby obtaining a dicyanobenzene-absorbed liquid comprising carboxylic acids;
(ii) bringing the dicyanobenzene-absorbed liquid into contact with a basic aqueous solution comprising a base under a temperature of 140° C. or lower, and extracting into an aqueous phase a water-soluble salt formed by a neutralization reaction between the base and the carboxylic acids in the dicyanobenzene-absorbed liquid, thereby obtaining a solution mixture of the dicyanobenzene-absorbed liquid and the basic aqueous solution;
(iii) separating the solution mixture of the dicyanobenzene-absorbed liquid and the basic aqueous solution into an organic phase and an aqueous phase;
(iv) distilling the organic phase, thereby separating part or all of components having a boiling point lower than a boiling point of the dicyanobenzene-absorbed liquid to obtain a molten dicyanobenzene;
and
(v) dissolving the molten dicyanobenzene in a solvent, followed by a liquid phase hydrogenation in the presence of a hydrogenation catalyst, thereby obtaining the xylylenediamine.

3 more elements

Dependencies are inferred from the claim text.