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:
Aug. 23, 1983
Filed:
Nov. 09, 1981
Konrad von Werner, Burgkirchen, DE;
Alfons Gisser, Burgkirchen, DE;
Hoechst Aktiengesellschaft, , DE;
Abstract
Saturated perfluoroalkane-1-carboxylic acids having 6 to 14 C atoms are prepared by reacting the corresponding 1-iodoperfluoroalkanes at temperatures of 100.degree. to 180.degree. C. with fuming sulfuric acid containing 15 to 45% by weight of dissolved sulfur trioxide. The two liquid phases which are formed are separated. The lighter phase is mixed with 0.3 to 6% of its weight of water and is distilled at a pressure of 0.3 to 100 kPa. The heavier phase is mixed with 0.7 to 1.5 moles of water per mole of sulfur trioxide employed and is cooled to 0.degree. to +30.degree. C. and the precipitated iodine is filtered off. After the addition of sulfur trioxide, the liquid filtrate can be re-used. Perfluoroalkan-1-oic acids are obtained in a high state of purity and the bulk of the iodine is recovered in the elementary form.