Toyo Ink Manufacturing Company

Shinichi Azuma

Shigeki Kato

Hideo Shimizu

Mikio Hayashi

Takanori Miyake

Takashi Kano

Hitoshi Maki

Masatoshi Momose

A process for producing highly pure 6,13-dihydroquinacridone, which is a suitable intermediate for effectively producing a quinacridone pigment, for a short period of time at high yields, the process comprising providing a cylindrical reactor, providing an atmosphere free of oxygen in the cylindrical reactor, heating the cylindrical reactor so that the temperature of at least a surface of an inner wall of a cylinder of the cylindrical reactor is in the range of from 250.degree. to 400.degree. C., introducing a powder of 2,5-di(arylamino)-3,6-dihydroterephthalic acid dialkyl ester or a mixture of 2,5-di(arylamino)-3,6-dihydroterephthalic acid dialkyl ester with a liquid through a feed port provided in an upper portion of the cylindrical reactor, keeping the powder or the mixture in substantial contact with the inner wall of the cylindrical reactor so that an intramolecular alcohol-elimination reaction of the 2,5-di(arylamino)-3,6-dihydroterephthalic acid dialkyl ester takes place to form 6,13-dihydroquinacridone, and taking out the 6,13-dihydroquinacridone through an outlet provided in a lower portion of the cylindrical reactor.

Process for the production of 6,13-dihydroquinacridones and apparatus

A process for producing a metal phthalocyanine pigment which comprises the steps of: reacting phthalic anhydride or a derivative thereof with urea or a derivative thereof with heating in the presence of a catalyst either in the presence or absence of an organic solvent; adding to the reaction mixture of the preceding step a metal or its compound capable of constituting the core of the metal phthalocyanine either alone or together with urea or a derivative thereof, without isolating the reaction product from the reaction mixture of the preceding step; and allowing the reaction mixture to react while simultaneously applying a mechanical grinding force in the presence or absence of a grinding agent.

Process for producing metal phthalocyanine pigment

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Tokyo, Japan

Shinichi Azuma