Method of condensing n-phenyl carbamates
CA 2022052 A1 · Owner: Mitsui Petrochemical Industries, Ltd. · Inventors: Matsunaga, Fujihisa; Yasuhara, Mitsuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention provides a process for producing 4,4'diphenylmethane dicarbamates through one stage condensation by reacting N-phenyl carbamates with a methylenating agent in presence of a zinc halide as a, catalyst. In accordance with the present invention 4,4'-, diphenylmethane dicarbamates can be produced with high selectivity and in high yield.
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 July 26, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 26, 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.