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. 27, 1976
Filed:
Sep. 14, 1973
Kazutoshi Inada, Minami-ashigara, JA;
Masatoshi Sugiyama, Odawara, JA;
Yasuo Nishigaki, Odawara, JA;
Sugihiko Tada, Minami-ashigara, JA;
Fuji Photo Film Co., Ltd., Minami-ashigara, JA;
Abstract
Crude hydroquinone containing impurities is purified in a sublimation purification apparatus where the crude hydroquinone is introduced into a stirred and fluidized bed, a carrier gas which is inert to the hydroquinone is passed therethrough, and the temperature therein is kept at about 110.degree.-170.degree.C whereby crude hydroquinone is sublimed, and thereafter a mixed gas consisting of the sublimed vapor and the carrier gas is introduced into a condenser at a temperature at about 25.degree.-90.degree.C whereby the hydroquinone only is fractionally solidified. After the sublimation purification, hydroquinone of high purity can be collected.