Title:
METHOD FOR PRODUCING PYROMELLITIC DIANHYDRIDE
Document Type and Number:
Japanese Patent JP2008297226
Kind Code:
A
Abstract:
To provide a commercially advantageous production method of high-purity pyromellitic dianhydride.
The production method of pyromellitic dianhydride comprises dissolving, in a solvent, crude pyromellitic acid containing insoluble fine powders to obtain a crude pyromellitic acid solution, filtering the crude solution through a filter having a pore size of 0.1-20 m to obtain a pyromellitic acid solution containing insoluble fine powders of at least 0.5 m in an amount of at most 1105 pieces per gram, and heating the pyromellitic acid solution in a liquid medium to cause a dehydration ring-closure reaction, or obtaining a crystal of pyromellitic acid from the pyromellitic acid solution and subjecting it to a heating dehydration reaction.
Inventors:
OGAWA HIROSHI
Application Number:
JP2007143139A
Publication Date:
December 11, 2008
Filing Date:
May 30, 2007
Export Citation:
Assignee:
MITSUBISHI GAS CHEMICAL CO
International Classes:
C07D493/04
Domestic Patent References:
| JPH03294272A | 1991-12-25 | |||
| JP2007051131A | 2007-03-01 | |||
| JPS6395264A | 1988-04-26 |
Foreign References:
| WO1994019725A1 | 1994-09-01 |
Other References:
JPN6012048711; 緒方章: 化学実験操作法上巻 第２７版, 1963, 第２５１-２５２頁
JPN6012048712; 日本化学会編: 化学便覧 応用化学編 第６版 , 200301, 第４章第１７６頁
JPN6012048712; 日本化学会編: 化学便覧 応用化学編 第６版 , 200301, 第４章第１７６頁
Attorney, Agent or Firm:
Takashi Nagai
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