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Expired European patentEurope

A method of preparing purified alkanesulfonic acid

EP 0505692 B1 · Applicant: ELF ATOCHEM NORTH AMERICA, INC.

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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.

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Why it's free to use

  • Filed January 31, 1992 and granted November 2, 1995. A European patent lasts at most 20 years from filing, so its term ended January 31, 2012.
  • 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 July 31, 2017.
  • 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.
FiledJanuary 31, 1992
PublishedSeptember 30, 1992
GrantedNovember 2, 1995
Term endedJanuary 31, 2012
Application numberEP 92101629
Classification (CPC)C07C303/44

Timeline

Timeline From EPO dates

1993199519971999200120032005200720092011Application filedJan 31, 1992PublishedSep 30, 1992Patent grantedNov 2, 1995Term endedJan 31, 2012

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

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