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:
Jan. 21, 2003
Filed:
Sep. 17, 2001
Susumu Otsuka, Niigata, JP;
Takuji Shitara, Niigata, JP;
Fumisada Kosuge, Niigata, JP;
Kazuhiko Amakawa, Niigata, JP;
Mitsubishi Gas Chemical Co. Inc., Tokyo, JP;
Abstract
In a method for separating isophthalonitrile from a gas produced by causing m-xylene to react with ammonia and oxygen-containing gas in the presence of a catalyst, the gas is brought into contact with an organic solvent having a boiling point lower than that of isophthalonitrile; a liquid in which isophthalonitrile is trapped in a trapping step is distilled, to thereby recover isophthalonitrile and the organic solvent from the top of the column and separate at the bottom of the column impurities having boiling points higher than that of isophthalonitrile; and the organic solvent is recovered from the top of the rectification column and liquefied isophthalonitrile of high purity is recovered at the bottom of the column. Thus, loss of isophthalonitrile and plugging of a vacuum-evacuation system caused by isophthalonitrile migrating from a condensation system during distillation under reduced pressure can be prevented, and high-purity isophthalonitrile can be produced at high yield constantly for a long period of time.