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:
Dec. 16, 2003
Filed:
Oct. 15, 2001
Toshihide Senzaki, Kitakyushu, JP;
Takahiro Imamura, Kitakyushu, JP;
Takeshi Takayama, Kitakyushu, JP;
Katsuhide Noguchi, Kitakyushu, JP;
Nippon Steel Chemical Co., Ltd., Tokyo, JP;
Abstract
This invention provides a process for purifying to a high degree of purity aromatic hydrocarbons containing impurities which are difficult to separate by distillation such as sulfur compounds and nitrogen compounds. The process of this invention for purifying aromatic hydrocarbons comprises treating crude aromatic hydrocarbons with a formaldehyde or with a formaldehyde and a phenol in the presence of an acid catalyst to form oligomers, distilling or evaporating the reaction mixture thereby separating the unreacted aromatic hydrocarbons from the oligomers, and crystallizing or washing with an organic solvent the separated aromatic hydrocarbons. In case the target hydrocarbon is naphthalene, it is possible to prepare naphthalene which has a purity of 99.9999 wt % or more, emits little odor, and can be readily flavored by perfumes. Naphthalene of this quality is used to prepare an insecticide of excellent fragrance.