Process for the isolation of paraffin sulfonates poor in alkalisulfates and sulfuric acid from paraffin sulfoxidation-reaction mixtures without the necessary production of sodium sulfate

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

Why it's free to use

• Filed November 13, 1987 and granted January 29, 1992. A European patent lasts at most 20 years from filing, so its term ended November 13, 2007.
• A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by May 13, 2013.
• We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.