Formaldehyde → Dihydrobenzoxazine

HRID 637623

Reaction equation

HRID 637623 reaction equation
[CH2:1]=[O:2].[OH-].[K+].[NH2:5][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.O[C:13]1C=CC(C(C2C=CC(O)=CC=2)(C)C)=CC=1>C1(C)C=CC=CC=1.CO>[O:2]1[C:1]2[CH:13]=[CH:7][CH:8]=[CH:9][C:10]=2[CH2:11][CH2:6][NH:5]1

Participants

7

Reactant 4

HCID 712FormaldehydeHCID 6115Aniline2×HCID 6623Bisphenol AHCID 14797Potassium Hydroxide

Product 1

HCID 21887592Dihydrobenzoxazine

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 1140TolueneSolvent

Procedure

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.

Workup

  1. temperatureThe mixture is warmed
  2. dissolutiondissolves
  3. additionare added to the paraform solution
  4. stirringis stirred for 15 minutes
  5. temperatureThe reaction is heated
  6. temperatureto atmospheric reflux
  7. temperaturerefluxed for 1 hour
  8. temperatureis being cooled
  9. customA water layer forms which is removed
  10. customThe toluene is removed
  11. temperatureby heating
  12. customuntil a temperature of 90° C.
  13. additionThe appropriate solvent is added at this point
  14. customclosed dihydrobenzoxazine ring of 87%

Sources & evidence

ORD record
ord-51ce1ec740604c1cb2be25c6918b2d43
Source dataset
uspto-grants-1985_12
Patent number
US04557979

Linked notes

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