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:
Nov. 11, 2003
Filed:
Jul. 02, 2002
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
In a method for producing xylylenediamine by hydrogenating phthalonitrile separated from a gas produced by causing xylene to react with ammonia and oxygen-containing gas in the presence of a catalyst, (1) the gas is brought into contact with an organic solvent to trap phthalonitrile; (2) a liquid in which phthalonitrile is trapped is distilled, to thereby recover phthalonitrile 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 phthalonitrile; (3) the organic solvent is recovered from the top of the column and liquefied phthalonitrile of high purity is recovered at the bottom of the column; and (4) the phthalonitrile is hydrogenated after mixing with liquid ammonia and at least one solvent selected from aromatic hydrocarbon and saturated hydrocarbon. Thus, high-purity phthalonitrile is produced at high yield industrially efficiently.