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Expired European patentEurope

Process for the preparation of substituted sulphonic acids and/or sulphonates

EP 0446971 B1 · Applicant: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.

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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 10, 1991 and granted July 27, 1994. A European patent lasts at most 20 years from filing, so its term ended January 10, 2011.
  • 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 10, 2016.
  • 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 10, 1991
PublishedSeptember 18, 1991
GrantedJuly 27, 1994
Term endedJanuary 10, 2011
Application numberEP 91200036
Classification (CPC)C07C319/14 +1 more

Timeline

Timeline From EPO dates

1992199419961998200020022004200620082010Application filedJan 10, 1991PublishedSep 18, 1991Patent grantedJuly 27, 1994Term endedJan 10, 2011

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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