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:
Jul. 04, 2000
Filed:
Feb. 26, 1998
Kazuhiko Sakamoto, Himeji, JP;
Fumio Shibusawa, Himeji, JP;
Sei Nakahara, Himeji, JP;
Takahiro Takeda, Himeji, JP;
Masatoshi Ueoka, Himeji, JP;
Nippon Shokubai Co Ltd, Osaka, JP;
Abstract
An improved method which enables stable and effective recovery of acrylic acid over a prolonged period is provided, said method comprising contacting an acrylic acid-containing gas obtained upon gas-phase catalytic oxidation of propylene and/or acrolein, with water, whereby collecting the acrylic acid in form of an aqueous solution, introducing said aqueous solution into an azeotropic separation column and distilling it in the presence of an azeotropic solvent to isolate and recover the acrylic acid, in which polymerization of the acrylic acid in the azeotropic separation column is prevented. Said method is characterized by using as the azeotropic solvent either a mixed solvent composed of solvent A (eg., ethyl acrylate, methyl methacrylate, etc.) and solvent B (eg., toluene, heptane, etc.) (first embodiment) or the solvent A alone (second embodiment).