Obtaining very pure maleic anhydride from crude maleic anhydride
CA 1292720 C · Owner: Basf Aktiengesellschaft · Inventors: Seubert, Rolf; Fischer, Karl; Zimmerling, Dieter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
7 - O.Z. 0050/37548, Abstract of the Disclosure: Very pure maleic anhydride having a stable color is obtained by fractional distillation of crude maleic anhydride by a method in which the maleic anhydride vapor separated off from low boilers and high boilers is partially condensed so that from 0.5 to 15% by weight of the maleic anhydride vapor is separated off from the vapor phase as a liquid precondensate and, the remaining very pure maleic anhydride vapor is then completely condensed.
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted December 3, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 3, 2008.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.