The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 06, 2000
Filed:
Dec. 30, 1996
Makoto Takagawa, Tsukuba, JP;
Ryusuke Shigematsu, Tsukuba, JP;
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
There are disclosed an industrially advantageous process for efficiently producing highly pure 2,6-dimethylnaphthalene (DMN) in high yield from a mixture of DMN by carrying out in turn, the steps of isomerizing a mixture of DMN in the presence of a catalyst; crystallizing the isomerization reaction product in the presence of a solvent (e.g. an aliphatic or alicyclic saturated hydrocarbon) to precipitate 2,6-DMN crystal; isolating and recovering the 2,6-DMN thus precipitated; and distilling the mother liquor formed after the isolation of the crystal to obtain DMN fraction by removing the components having a higher boiling point than DMN and the components having a lower boiling point than DMN, while at least part of the DMN fraction is returned to the isomerization step and circulated through the process; a process for producing a 2,6-naphthalenedicarboxylic acid by subjecting the 2,6-DMN obtained by the above process to liquid-phase oxidation; and a process for producing 2,6-naphthalenedicarboxylic acid ester by esterifying 2,6-naphthalenedicarboxylic acid thus produced.