Formaldehyde → Dihydrobenzoxazine

Participants

Reaction Steps

To a reactor are charged 66 parts of paraformaldehyde, 66 parts of methanol and 1 part of potassium hydroxide. The mixture is warmed and stirred until the paraform dissolves. While the temperature is maintained in the 25°-35° C. range, 93 parts of aniline are added to the paraform solution. Upon completion of the aniline addition the reaction is stirred for 15 minutes and then 114 parts of bisphenol A are added. The reaction is heated to atmospheric reflux and refluxed for 1 hour. After 1 hour, toluene (100 parts) is added to the reaction mixture while it is being cooled. A water layer forms which is removed. The toluene is removed by heating and applying reduced pressure until a temperature of 90° C. at 7 kPa pressure is reached. The appropriate solvent is added at this point. The devolitilized resin has a % closed dihydrobenzoxazine ring of 87%, and a calculated equivalent weight of 262.

Provenance & Evidence