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:
Apr. 29, 2003
Filed:
May. 22, 2000
UBE Industries, Ltd., Yamaguchi, JP;
Abstract
A refined dihydroxyaryl compound, for example, catechol, having a high degree of purity and a very low metal content is produced by evaporating a starting dihydroxyaryl compound in a distillation column, condensing the vapor fraction in a condenser connected to a top outlet of the distillation column, and collecting the condensed fraction from the condenser into a storage tank through a conduit, wherein the condenser and optionally the conduit and/or the storage tank have inside surfaces thereof formed from a metal material containing at least 25% by weight of nickel, and the condensed dihydroxyaryl compound fraction is brought into contact with the specific nickel (25% or more)-containing metal inside surface.