Process for the preparation of pyrazole
CA 1161443 A · Owner: Bayer Aktiengesellschaft · Inventors: Weber, Erhard; Heinemann, Ulrich; Lantzsch, Reinhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for the preparation of pyrazole by reacting hydrazine hydrate with acrolein in an aqueous-organic medium at a temperature between 20°C and 80°C and, oxidising the 2-pyrazoline formed of the formula, (I), either directly, or where appropriate after first being isolated, with chlorine or an alkali metal hypochlorite or an alkaline earth metal hypochlorite in water or an aqueous-organic medium at a temperature between 0°C and 60°C, if necessary in the presence of a catalyst. Le A 20 593
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
- Granted January 31, 1984. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 31, 2001.
- 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.