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Expired Canadian patentCanada

Process for the production of polyalkylaromatic polysulfonic acids and recovery by heavy phase separation

CA 1255695 A · Owner: King Industries, Inc. · Inventors: Gallacher, Lawrence V.; Condos, Harry N.

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

This invention relates to novel processes for the production of enhanced yields of polyalkylaromatic polysulfonic acids. More particularly, the invention pertains to processes for sulfonating polyalkylaromatic compounds employing sulfuric acid treatment and recovering the polyalkylaromatic polysulfonic acid produced thereby after formation of a three phase system by the addition of controlled amounts of water causing the, polysulfonic acid to accumulate in the bottom layer with which it is readily separated.

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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 June 13, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 13, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 26, 1985
GrantedJune 13, 1989
Term endedJune 13, 2006
Patent numberCA 1255695 A
Classification (IPC)C07C303/44 +1 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedJune 26, 1985Patent grantedJune 13, 1989Term endedJune 13, 2006

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.