Process for the production of 2,3,5-trimethylhydroquinone diesters
CA 2297357 A1 · Owner: Degussa-Huls Aktiengesellschaft · Inventors: Huthmacher, Klaus; Markowz, Georg; Krill, Steffen
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a process for the production of 2,3,5-trimethylhydroquinone diesters by aromatisation of 2,6,6-trimethyl-2-cyclohexene-1,4-dione (4-oxoisophorone ketoisophorone, KIP) with an acylating agent and an acidic soluble or insoluble catalyst, which process may be operated alternatively continuously or discontinuously. A carboxylic anhydride having a C1 to C9 alkyl residue is used as the acylating agent, and after the reaction a, portion of the resultant carboxylic acid optionally may be removed by distillation. The reaction solution is cooled the product which has crystallised out is separated and washed, and the filtrate is returned to the reaction.
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 January 27, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 27, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 27, 2022.
- 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.