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. 17, 1995
Filed:
Mar. 23, 1994
Hiromoto Ohno, Kanagawa, JP;
Tatsuharu Arai, Kanagawa, JP;
Koichi Katamura, Kanagawa, JP;
Sadayoshi Yuge, Kanagawa, JP;
Haruyuki Kawai, Kanagawa, JP;
Yasuaki Morito, Kanagawa, JP;
Showa Denko Kabushiki Kaisha, Tokyo, JP;
Abstract
A process for purifying 1,1,1,2-tetrafluoroethane which comprises allowing an HF-containing 1,1,1,2-tetrafluoroethane-concentrated fraction to contact at a low temperature with hydrofluoric acid which is an extraction solvent and has an HF concentration equal to or higher than an HF concentration at a water-HF azeotropic point, thereby effecting two-phase separation, and subsequently recovering 1,1,1,2-tetrafluoroethane from the separated lower phase, wherein hydrofluoric acid to be used as the extraction solvent has a concentration of from 38 to 70% by weight, and the extraction and two-phase separation steps are effected at a temperature of from -35.degree. to 35.degree. C. According to the purification process, HF can be recovered economically from a 1,1,1,2-tetrafluoroethane fraction containing a small amount of HF.