Process for preparing sulphonated dispersants
CA 2005278 A1 · Owner: Snamprogetti S.P.A. · Inventors: Prevedello, Aldo; Donati, Elio; Marcotullio, Armando
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Sulphonated dispersants are prepared by a process comprising: - bringing liquid or gaseous sulphur trioxide into contact under sulphonation conditions with a solution of a tar in liquid sulphur dioxide, - removing the sulphur dioxide from the reaction mixture by vaporization and recovering the sulphonated tar and, - salifying the sulphonated tar with an aqueous solution of an alkaline metal hydroxide or ammonium hydroxide. The sulphonated dispersants prepared in this manner are completely water soluble and are particularly useful as fluidifying and stabilizing agents in aqueous dispersions of solids such as coal and cement.
Read the whole patent
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
- Filed December 12, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 12, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 12, 2011.
- 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
Timeline From CIPO dates
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.