Process for producing cyclic ureas
CA 1283101 C · Owner: Wada, Masaru · Inventors: Kajimoto, Nobuyuki; Wada, Masaru; Nagata, Teruyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for producing a cyclic urea by reacting a diamine directly with phosgene with a high yield and a cheap cost is provided, which process comprises reacting a diamine expressed by the Formula, R-HN-R'-NH-R wherein R represents hydrogen atom or a lower alkyl group and R' represents dimethylene group, trimethylene group tetramethylene group or a lower alkyl group-substituted dimethylene group, trimethylene group or tetramethylene group except for three particular combinations of R with R', with phosgene substantially in the presence of water and a dehydrochlorinating agent to obtain a cyclic urea expressed by the formula, wherein R and R' are as defined above.
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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 April 16, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 16, 2008.
- 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.