Process for the preparation of 2,2-dimethylpropane-1,3-diol
CA 2032323 C · Owner: Hoechst Aktiengesellschaft · Inventors: Lappe,Peter; Springer, Helmut; Dambkes, Georg
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for the preparation of 2,2-dimethylpropane-1,3-diol by an addition reaction between isobutyraldehyde and formaldehyde in the presence of tertiary amines as the catalyst, hydrogenation of the reaction mixture and subsequent distillation. Before the distillation, formaldehyde is added to the hydrogenation product to remove troublesome basic impurities.
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 14, 1990 and granted April 28, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 14, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 14, 2012.
- 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.