Title:
PRODUCTION OF PHTHALIC ACID DERIVATIVE
Document Type and Number:
Japanese Patent JP3739119
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To industrially obtain in high purity and yield a phthalic acid derivative useful as an intermediate for polyimides, by heating a specific phthalonitrile derivative under an acidic condition to form a reaction product which is then dissolved in a specific medium and separated, and by heating the product in an acidic medium and then separating the product.
SOLUTION: First, a compound of formula I (X is a halogen) such as 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrafluorobenzene is heated in an acidic aqueous medium to form a product containing a compound A of formula II such as 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene. Subsequently, the product is once dissolved in an medium containing an organic solvent (e.g. containing at least 50wt.% of a ketone) and then separated, and the product is, in turn, heated in an acidic aqueous medium; the above process is repeated, and, finally, the product containing the compound A is separated from the acidic medium.
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Inventors:
Yasunori Okumura
Takashi Yoshinori
Osamu Kaieda
Takashi Yoshinori
Osamu Kaieda
Application Number:
JP26600795A
Publication Date:
January 25, 2006
Filing Date:
October 13, 1995
Export Citation:
Assignee:
Nippon Shokubai Co., Ltd.
International Classes:
C07C65/24; G02B1/04; C07C51/08; (IPC1-7): C07C65/24; C07C51/08; //G02B1/04
Domestic Patent References:
| JP5001148A | ||||
| JP47050098B1 | ||||
| JP9067296A | ||||
| JP62111942A |
Attorney, Agent or Firm:
Mikio Hatta